/*
 * A driver for the ARM PL022 PrimeCell SSP/SPI bus master.
 *
 * Copyright (C) 2008-2012 ST-Ericsson AB
 * Copyright (C) 2006 STMicroelectronics Pvt. Ltd.
 *
 * Author: Linus Walleij <linus.walleij@stericsson.com>
 *
 * Initial version inspired by:
 *      linux-2.6.17-rc3-mm1/drivers/spi/pxa2xx_spi.c
 * Initial adoption to PL022 by:
 *      Sachin Verma <sachin.verma@st.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/spi/spi.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/amba/bus.h>
#include <linux/amba/pl022.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>
#include <linux/pm_runtime.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/pinctrl/consumer.h>

/*
 * This macro is used to define some register default values.
 * reg is masked with mask, the OR:ed with an (again masked)
 * val shifted sb steps to the left.
 */
#define SSP_WRITE_BITS(reg, val, mask, sb) \
 ((reg) = (((reg) & ~(mask)) | (((val)<<(sb)) & (mask))))

/*
 * This macro is also used to define some default values.
 * It will just shift val by sb steps to the left and mask
 * the result with mask.
 */
#define GEN_MASK_BITS(val, mask, sb) \
 (((val)<<(sb)) & (mask))

#define DRIVE_TX                0
#define DO_NOT_DRIVE_TX         1

#define DO_NOT_QUEUE_DMA        0
#define QUEUE_DMA               1

#define RX_TRANSFER             1
#define TX_TRANSFER             2

/*
 * Macros to access SSP Registers with their offsets
 */
#define SSP_CR0(r)      (r + 0x000)
#define SSP_CR1(r)      (r + 0x004)
#define SSP_DR(r)       (r + 0x008)
#define SSP_SR(r)       (r + 0x00C)
#define SSP_CPSR(r)     (r + 0x010)
#define SSP_IMSC(r)     (r + 0x014)
#define SSP_RIS(r)      (r + 0x018)
#define SSP_MIS(r)      (r + 0x01C)
#define SSP_ICR(r)      (r + 0x020)
#define SSP_DMACR(r)    (r + 0x024)
#define SSP_CSR(r)      (r + 0x030) /* vendor extension */
#define SSP_ITCR(r)     (r + 0x080)
#define SSP_ITIP(r)     (r + 0x084)
#define SSP_ITOP(r)     (r + 0x088)
#define SSP_TDR(r)      (r + 0x08C)

#define SSP_PID0(r)     (r + 0xFE0)
#define SSP_PID1(r)     (r + 0xFE4)
#define SSP_PID2(r)     (r + 0xFE8)
#define SSP_PID3(r)     (r + 0xFEC)

#define SSP_CID0(r)     (r + 0xFF0)
#define SSP_CID1(r)     (r + 0xFF4)
#define SSP_CID2(r)     (r + 0xFF8)
#define SSP_CID3(r)     (r + 0xFFC)

/*
 * SSP Control Register 0  - SSP_CR0
 */
#define SSP_CR0_MASK_DSS        (0x0FUL << 0)
#define SSP_CR0_MASK_FRF        (0x3UL << 4)
#define SSP_CR0_MASK_SPO        (0x1UL << 6)
#define SSP_CR0_MASK_SPH        (0x1UL << 7)
#define SSP_CR0_MASK_SCR        (0xFFUL << 8)

/*
 * The ST version of this block moves som bits
 * in SSP_CR0 and extends it to 32 bits
 */
#define SSP_CR0_MASK_DSS_ST     (0x1FUL << 0)
#define SSP_CR0_MASK_HALFDUP_ST (0x1UL << 5)
#define SSP_CR0_MASK_CSS_ST     (0x1FUL << 16)
#define SSP_CR0_MASK_FRF_ST     (0x3UL << 21)

/*
 * SSP Control Register 0  - SSP_CR1
 */
#define SSP_CR1_MASK_LBM        (0x1UL << 0)
#define SSP_CR1_MASK_SSE        (0x1UL << 1)
#define SSP_CR1_MASK_MS         (0x1UL << 2)
#define SSP_CR1_MASK_SOD        (0x1UL << 3)

/*
 * The ST version of this block adds some bits
 * in SSP_CR1
 */
#define SSP_CR1_MASK_RENDN_ST   (0x1UL << 4)
#define SSP_CR1_MASK_TENDN_ST   (0x1UL << 5)
#define SSP_CR1_MASK_MWAIT_ST   (0x1UL << 6)
#define SSP_CR1_MASK_RXIFLSEL_ST (0x7UL << 7)
#define SSP_CR1_MASK_TXIFLSEL_ST (0x7UL << 10)
/* This one is only in the PL023 variant */
#define SSP_CR1_MASK_FBCLKDEL_ST (0x7UL << 13)

/*
 * SSP Status Register - SSP_SR
 */
#define SSP_SR_MASK_TFE         (0x1UL << 0) /* Transmit FIFO empty */
#define SSP_SR_MASK_TNF         (0x1UL << 1) /* Transmit FIFO not full */
#define SSP_SR_MASK_RNE         (0x1UL << 2) /* Receive FIFO not empty */
#define SSP_SR_MASK_RFF         (0x1UL << 3) /* Receive FIFO full */
#define SSP_SR_MASK_BSY         (0x1UL << 4) /* Busy Flag */

/*
 * SSP Clock Prescale Register  - SSP_CPSR
 */
#define SSP_CPSR_MASK_CPSDVSR   (0xFFUL << 0)

/*
 * SSP Interrupt Mask Set/Clear Register - SSP_IMSC
 */
#define SSP_IMSC_MASK_RORIM (0x1UL << 0) /* Receive Overrun Interrupt mask */
#define SSP_IMSC_MASK_RTIM  (0x1UL << 1) /* Receive timeout Interrupt mask */
#define SSP_IMSC_MASK_RXIM  (0x1UL << 2) /* Receive FIFO Interrupt mask */
#define SSP_IMSC_MASK_TXIM  (0x1UL << 3) /* Transmit FIFO Interrupt mask */

/*
 * SSP Raw Interrupt Status Register - SSP_RIS
 */
/* Receive Overrun Raw Interrupt status */
#define SSP_RIS_MASK_RORRIS             (0x1UL << 0)
/* Receive Timeout Raw Interrupt status */
#define SSP_RIS_MASK_RTRIS              (0x1UL << 1)
/* Receive FIFO Raw Interrupt status */
#define SSP_RIS_MASK_RXRIS              (0x1UL << 2)
/* Transmit FIFO Raw Interrupt status */
#define SSP_RIS_MASK_TXRIS              (0x1UL << 3)

/*
 * SSP Masked Interrupt Status Register - SSP_MIS
 */
/* Receive Overrun Masked Interrupt status */
#define SSP_MIS_MASK_RORMIS             (0x1UL << 0)
/* Receive Timeout Masked Interrupt status */
#define SSP_MIS_MASK_RTMIS              (0x1UL << 1)
/* Receive FIFO Masked Interrupt status */
#define SSP_MIS_MASK_RXMIS              (0x1UL << 2)
/* Transmit FIFO Masked Interrupt status */
#define SSP_MIS_MASK_TXMIS              (0x1UL << 3)

/*
 * SSP Interrupt Clear Register - SSP_ICR
 */
/* Receive Overrun Raw Clear Interrupt bit */
#define SSP_ICR_MASK_RORIC              (0x1UL << 0)
/* Receive Timeout Clear Interrupt bit */
#define SSP_ICR_MASK_RTIC               (0x1UL << 1)

/*
 * SSP DMA Control Register - SSP_DMACR
 */
/* Receive DMA Enable bit */
#define SSP_DMACR_MASK_RXDMAE           (0x1UL << 0)
/* Transmit DMA Enable bit */
#define SSP_DMACR_MASK_TXDMAE           (0x1UL << 1)

/*
 * SSP Chip Select Control Register - SSP_CSR
 * (vendor extension)
 */
#define SSP_CSR_CSVALUE_MASK            (0x1FUL << 0)

/*
 * SSP Integration Test control Register - SSP_ITCR
 */
#define SSP_ITCR_MASK_ITEN              (0x1UL << 0)
#define SSP_ITCR_MASK_TESTFIFO          (0x1UL << 1)

/*
 * SSP Integration Test Input Register - SSP_ITIP
 */
#define ITIP_MASK_SSPRXD                 (0x1UL << 0)
#define ITIP_MASK_SSPFSSIN               (0x1UL << 1)
#define ITIP_MASK_SSPCLKIN               (0x1UL << 2)
#define ITIP_MASK_RXDMAC                 (0x1UL << 3)
#define ITIP_MASK_TXDMAC                 (0x1UL << 4)
#define ITIP_MASK_SSPTXDIN               (0x1UL << 5)

/*
 * SSP Integration Test output Register - SSP_ITOP
 */
#define ITOP_MASK_SSPTXD                 (0x1UL << 0)
#define ITOP_MASK_SSPFSSOUT              (0x1UL << 1)
#define ITOP_MASK_SSPCLKOUT              (0x1UL << 2)
#define ITOP_MASK_SSPOEn                 (0x1UL << 3)
#define ITOP_MASK_SSPCTLOEn              (0x1UL << 4)
#define ITOP_MASK_RORINTR                (0x1UL << 5)
#define ITOP_MASK_RTINTR                 (0x1UL << 6)
#define ITOP_MASK_RXINTR                 (0x1UL << 7)
#define ITOP_MASK_TXINTR                 (0x1UL << 8)
#define ITOP_MASK_INTR                   (0x1UL << 9)
#define ITOP_MASK_RXDMABREQ              (0x1UL << 10)
#define ITOP_MASK_RXDMASREQ              (0x1UL << 11)
#define ITOP_MASK_TXDMABREQ              (0x1UL << 12)
#define ITOP_MASK_TXDMASREQ              (0x1UL << 13)

/*
 * SSP Test Data Register - SSP_TDR
 */
#define TDR_MASK_TESTDATA               (0xFFFFFFFF)

/*
 * Message State
 * we use the spi_message.state (void *) pointer to
 * hold a single state value, that's why all this
 * (void *) casting is done here.
 */
#define STATE_START                     ((void *) 0)
#define STATE_RUNNING                   ((void *) 1)
#define STATE_DONE                      ((void *) 2)
#define STATE_ERROR                     ((void *) -1)

/*
 * SSP State - Whether Enabled or Disabled
 */
#define SSP_DISABLED                    (0)
#define SSP_ENABLED                     (1)

/*
 * SSP DMA State - Whether DMA Enabled or Disabled
 */
#define SSP_DMA_DISABLED                (0)
#define SSP_DMA_ENABLED                 (1)

/*
 * SSP Clock Defaults
 */
#define SSP_DEFAULT_CLKRATE 0x2
#define SSP_DEFAULT_PRESCALE 0x40

/*
 * SSP Clock Parameter ranges
 */
#define CPSDVR_MIN 0x02
#define CPSDVR_MAX 0xFE
#define SCR_MIN 0x00
#define SCR_MAX 0xFF

/*
 * SSP Interrupt related Macros
 */
#define DEFAULT_SSP_REG_IMSC  0x0UL
#define DISABLE_ALL_INTERRUPTS DEFAULT_SSP_REG_IMSC
#define ENABLE_ALL_INTERRUPTS ( \
        SSP_IMSC_MASK_RORIM | \
        SSP_IMSC_MASK_RTIM | \
        SSP_IMSC_MASK_RXIM | \
        SSP_IMSC_MASK_TXIM \
)

#define CLEAR_ALL_INTERRUPTS  0x3

#define SPI_POLLING_TIMEOUT 1000

/*
 * The type of reading going on on this chip
 */
enum ssp_reading {
        READING_NULL,
        READING_U8,
        READING_U16,
        READING_U32
};

/**
 * The type of writing going on on this chip
 */
enum ssp_writing {
        WRITING_NULL,
        WRITING_U8,
        WRITING_U16,
        WRITING_U32
};

/**
 * struct vendor_data - vendor-specific config parameters
 * for PL022 derivates
 * @fifodepth: depth of FIFOs (both)
 * @max_bpw: maximum number of bits per word
 * @unidir: supports unidirection transfers
 * @extended_cr: 32 bit wide control register 0 with extra
 * features and extra features in CR1 as found in the ST variants
 * @pl023: supports a subset of the ST extensions called "PL023"
 * @internal_cs_ctrl: supports chip select control register
 */
struct vendor_data {
        int fifodepth;
        int max_bpw;
        bool unidir;
        bool extended_cr;
        bool pl023;
        bool loopback;
        bool internal_cs_ctrl;
};

/**
 * struct pl022 - This is the private SSP driver data structure
 * @adev: AMBA device model hookup
 * @vendor: vendor data for the IP block
 * @phybase: the physical memory where the SSP device resides
 * @virtbase: the virtual memory where the SSP is mapped
 * @clk: outgoing clock "SPICLK" for the SPI bus
 * @master: SPI framework hookup
 * @master_info: controller-specific data from machine setup
 * @pump_transfers: Tasklet used in Interrupt Transfer mode
 * @cur_msg: Pointer to current spi_message being processed
 * @cur_transfer: Pointer to current spi_transfer
 * @cur_chip: pointer to current clients chip(assigned from controller_state)
 * @next_msg_cs_active: the next message in the queue has been examined
 *  and it was found that it uses the same chip select as the previous
 *  message, so we left it active after the previous transfer, and it's
 *  active already.
 * @tx: current position in TX buffer to be read
 * @tx_end: end position in TX buffer to be read
 * @rx: current position in RX buffer to be written
 * @rx_end: end position in RX buffer to be written
 * @read: the type of read currently going on
 * @write: the type of write currently going on
 * @exp_fifo_level: expected FIFO level
 * @dma_rx_channel: optional channel for RX DMA
 * @dma_tx_channel: optional channel for TX DMA
 * @sgt_rx: scattertable for the RX transfer
 * @sgt_tx: scattertable for the TX transfer
 * @dummypage: a dummy page used for driving data on the bus with DMA
 * @cur_cs: current chip select (gpio)
 * @chipselects: list of chipselects (gpios)
 */
struct pl022 {
        struct amba_device              *adev;
        struct vendor_data              *vendor;
        resource_size_t                 phybase;
        void __iomem                    *virtbase;
        struct clk                      *clk;
        struct spi_master               *master;
        struct pl022_ssp_controller     *master_info;
        /* Message per-transfer pump */
        struct tasklet_struct           pump_transfers;
        struct spi_message              *cur_msg;
        struct spi_transfer             *cur_transfer;
        struct chip_data                *cur_chip;
        bool                            next_msg_cs_active;
        void                            *tx;
        void                            *tx_end;
        void                            *rx;
        void                            *rx_end;
        enum ssp_reading                read;
        enum ssp_writing                write;
        u32                             exp_fifo_level;
        enum ssp_rx_level_trig          rx_lev_trig;
        enum ssp_tx_level_trig          tx_lev_trig;
        /* DMA settings */
#ifdef CONFIG_DMA_ENGINE
        struct dma_chan                 *dma_rx_channel;
        struct dma_chan                 *dma_tx_channel;
        struct sg_table                 sgt_rx;
        struct sg_table                 sgt_tx;
        char                            *dummypage;
        bool                            dma_running;
#endif
        int cur_cs;
        int *chipselects;
};

/**
 * struct chip_data - To maintain runtime state of SSP for each client chip
 * @cr0: Value of control register CR0 of SSP - on later ST variants this
 *       register is 32 bits wide rather than just 16
 * @cr1: Value of control register CR1 of SSP
 * @dmacr: Value of DMA control Register of SSP
 * @cpsr: Value of Clock prescale register
 * @n_bytes: how many bytes(power of 2) reqd for a given data width of client
 * @enable_dma: Whether to enable DMA or not
 * @read: function ptr to be used to read when doing xfer for this chip
 * @write: function ptr to be used to write when doing xfer for this chip
 * @cs_control: chip select callback provided by chip
 * @xfer_type: polling/interrupt/DMA
 *
 * Runtime state of the SSP controller, maintained per chip,
 * This would be set according to the current message that would be served
 */
struct chip_data {
        u32 cr0;
        u16 cr1;
        u16 dmacr;
        u16 cpsr;
        u8 n_bytes;
        bool enable_dma;
        enum ssp_reading read;
        enum ssp_writing write;
        void (*cs_control) (u32 command);
        int xfer_type;
};

/**
 * null_cs_control - Dummy chip select function
 * @command: select/delect the chip
 *
 * If no chip select function is provided by client this is used as dummy
 * chip select
 */
static void null_cs_control(u32 command)
{
        pr_debug("pl022: dummy chip select control, CS=0x%x\n", command);
}

/**
 * internal_cs_control - Control chip select signals via SSP_CSR.
 * @pl022: SSP driver private data structure
 * @command: select/delect the chip
 *
 * Used on controller with internal chip select control via SSP_CSR register
 * (vendor extension). Each of the 5 LSB in the register controls one chip
 * select signal.
 */
static void internal_cs_control(struct pl022 *pl022, u32 command)
{
        u32 tmp;

        tmp = readw(SSP_CSR(pl022->virtbase));
        if (command == SSP_CHIP_SELECT)
                tmp &= ~BIT(pl022->cur_cs);
        else
                tmp |= BIT(pl022->cur_cs);
        writew(tmp, SSP_CSR(pl022->virtbase));
}

static void pl022_cs_control(struct pl022 *pl022, u32 command)
{
        if (pl022->vendor->internal_cs_ctrl)
                internal_cs_control(pl022, command);
        else if (gpio_is_valid(pl022->cur_cs))
                gpio_set_value(pl022->cur_cs, command);
        else
                pl022->cur_chip->cs_control(command);
}

/**
 * giveback - current spi_message is over, schedule next message and call
 * callback of this message. Assumes that caller already
 * set message->status; dma and pio irqs are blocked
 * @pl022: SSP driver private data structure
 */
static void giveback(struct pl022 *pl022)
{
        struct spi_transfer *last_transfer;
        pl022->next_msg_cs_active = false;

        last_transfer = list_last_entry(&pl022->cur_msg->transfers,
                                        struct spi_transfer, transfer_list);

        /* Delay if requested before any change in chip select */
        if (last_transfer->delay_usecs)
                /*
                 * FIXME: This runs in interrupt context.
                 * Is this really smart?
                 */
                udelay(last_transfer->delay_usecs);

        if (!last_transfer->cs_change) {
                struct spi_message *next_msg;

                /*
                 * cs_change was not set. We can keep the chip select
                 * enabled if there is message in the queue and it is
                 * for the same spi device.
                 *
                 * We cannot postpone this until pump_messages, because
                 * after calling msg->complete (below) the driver that
                 * sent the current message could be unloaded, which
                 * could invalidate the cs_control() callback...
                 */
                /* get a pointer to the next message, if any */
                next_msg = spi_get_next_queued_message(pl022->master);

                /*
                 * see if the next and current messages point
                 * to the same spi device.
                 */
                if (next_msg && next_msg->spi != pl022->cur_msg->spi)
                        next_msg = NULL;
                if (!next_msg || pl022->cur_msg->state == STATE_ERROR)
                        pl022_cs_control(pl022, SSP_CHIP_DESELECT);
                else
                        pl022->next_msg_cs_active = true;

        }

        pl022->cur_msg = NULL;
        pl022->cur_transfer = NULL;
        pl022->cur_chip = NULL;

        /* disable the SPI/SSP operation */
        writew((readw(SSP_CR1(pl022->virtbase)) &
                (~SSP_CR1_MASK_SSE)), SSP_CR1(pl022->virtbase));

        spi_finalize_current_message(pl022->master);
}

/**
 * flush - flush the FIFO to reach a clean state
 * @pl022: SSP driver private data structure
 */
static int flush(struct pl022 *pl022)
{
        unsigned long limit = loops_per_jiffy << 1;

        dev_dbg(&pl022->adev->dev, "flush\n");
        do {
                while (readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_RNE)
                        readw(SSP_DR(pl022->virtbase));
        } while ((readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_BSY) && limit--);

        pl022->exp_fifo_level = 0;

        return limit;
}

/**
 * restore_state - Load configuration of current chip
 * @pl022: SSP driver private data structure
 */
static void restore_state(struct pl022 *pl022)
{
        struct chip_data *chip = pl022->cur_chip;

        if (pl022->vendor->extended_cr)
                writel(chip->cr0, SSP_CR0(pl022->virtbase));
        else
                writew(chip->cr0, SSP_CR0(pl022->virtbase));
        writew(chip->cr1, SSP_CR1(pl022->virtbase));
        writew(chip->dmacr, SSP_DMACR(pl022->virtbase));
        writew(chip->cpsr, SSP_CPSR(pl022->virtbase));
        writew(DISABLE_ALL_INTERRUPTS, SSP_IMSC(pl022->virtbase));
        writew(CLEAR_ALL_INTERRUPTS, SSP_ICR(pl022->virtbase));
}

/*
 * Default SSP Register Values
 */
#define DEFAULT_SSP_REG_CR0 ( \
        GEN_MASK_BITS(SSP_DATA_BITS_12, SSP_CR0_MASK_DSS, 0)    | \
        GEN_MASK_BITS(SSP_INTERFACE_MOTOROLA_SPI, SSP_CR0_MASK_FRF, 4) | \
        GEN_MASK_BITS(SSP_CLK_POL_IDLE_LOW, SSP_CR0_MASK_SPO, 6) | \
        GEN_MASK_BITS(SSP_CLK_SECOND_EDGE, SSP_CR0_MASK_SPH, 7) | \
        GEN_MASK_BITS(SSP_DEFAULT_CLKRATE, SSP_CR0_MASK_SCR, 8) \
)

/* ST versions have slightly different bit layout */
#define DEFAULT_SSP_REG_CR0_ST ( \
        GEN_MASK_BITS(SSP_DATA_BITS_12, SSP_CR0_MASK_DSS_ST, 0) | \
        GEN_MASK_BITS(SSP_MICROWIRE_CHANNEL_FULL_DUPLEX, SSP_CR0_MASK_HALFDUP_ST, 5) | \
        GEN_MASK_BITS(SSP_CLK_POL_IDLE_LOW, SSP_CR0_MASK_SPO, 6) | \
        GEN_MASK_BITS(SSP_CLK_SECOND_EDGE, SSP_CR0_MASK_SPH, 7) | \
        GEN_MASK_BITS(SSP_DEFAULT_CLKRATE, SSP_CR0_MASK_SCR, 8) | \
        GEN_MASK_BITS(SSP_BITS_8, SSP_CR0_MASK_CSS_ST, 16)      | \
        GEN_MASK_BITS(SSP_INTERFACE_MOTOROLA_SPI, SSP_CR0_MASK_FRF_ST, 21) \
)

/* The PL023 version is slightly different again */
#define DEFAULT_SSP_REG_CR0_ST_PL023 ( \
        GEN_MASK_BITS(SSP_DATA_BITS_12, SSP_CR0_MASK_DSS_ST, 0) | \
        GEN_MASK_BITS(SSP_CLK_POL_IDLE_LOW, SSP_CR0_MASK_SPO, 6) | \
        GEN_MASK_BITS(SSP_CLK_SECOND_EDGE, SSP_CR0_MASK_SPH, 7) | \
        GEN_MASK_BITS(SSP_DEFAULT_CLKRATE, SSP_CR0_MASK_SCR, 8) \
)

#define DEFAULT_SSP_REG_CR1 ( \
        GEN_MASK_BITS(LOOPBACK_DISABLED, SSP_CR1_MASK_LBM, 0) | \
        GEN_MASK_BITS(SSP_DISABLED, SSP_CR1_MASK_SSE, 1) | \
        GEN_MASK_BITS(SSP_MASTER, SSP_CR1_MASK_MS, 2) | \
        GEN_MASK_BITS(DO_NOT_DRIVE_TX, SSP_CR1_MASK_SOD, 3) \
)

/* ST versions extend this register to use all 16 bits */
#define DEFAULT_SSP_REG_CR1_ST ( \
        DEFAULT_SSP_REG_CR1 | \
        GEN_MASK_BITS(SSP_RX_MSB, SSP_CR1_MASK_RENDN_ST, 4) | \
        GEN_MASK_BITS(SSP_TX_MSB, SSP_CR1_MASK_TENDN_ST, 5) | \
        GEN_MASK_BITS(SSP_MWIRE_WAIT_ZERO, SSP_CR1_MASK_MWAIT_ST, 6) |\
        GEN_MASK_BITS(SSP_RX_1_OR_MORE_ELEM, SSP_CR1_MASK_RXIFLSEL_ST, 7) | \
        GEN_MASK_BITS(SSP_TX_1_OR_MORE_EMPTY_LOC, SSP_CR1_MASK_TXIFLSEL_ST, 10) \
)

/*
 * The PL023 variant has further differences: no loopback mode, no microwire
 * support, and a new clock feedback delay setting.
 */
#define DEFAULT_SSP_REG_CR1_ST_PL023 ( \
        GEN_MASK_BITS(SSP_DISABLED, SSP_CR1_MASK_SSE, 1) | \
        GEN_MASK_BITS(SSP_MASTER, SSP_CR1_MASK_MS, 2) | \
        GEN_MASK_BITS(DO_NOT_DRIVE_TX, SSP_CR1_MASK_SOD, 3) | \
        GEN_MASK_BITS(SSP_RX_MSB, SSP_CR1_MASK_RENDN_ST, 4) | \
        GEN_MASK_BITS(SSP_TX_MSB, SSP_CR1_MASK_TENDN_ST, 5) | \
        GEN_MASK_BITS(SSP_RX_1_OR_MORE_ELEM, SSP_CR1_MASK_RXIFLSEL_ST, 7) | \
        GEN_MASK_BITS(SSP_TX_1_OR_MORE_EMPTY_LOC, SSP_CR1_MASK_TXIFLSEL_ST, 10) | \
        GEN_MASK_BITS(SSP_FEEDBACK_CLK_DELAY_NONE, SSP_CR1_MASK_FBCLKDEL_ST, 13) \
)

#define DEFAULT_SSP_REG_CPSR ( \
        GEN_MASK_BITS(SSP_DEFAULT_PRESCALE, SSP_CPSR_MASK_CPSDVSR, 0) \
)

#define DEFAULT_SSP_REG_DMACR (\
        GEN_MASK_BITS(SSP_DMA_DISABLED, SSP_DMACR_MASK_RXDMAE, 0) | \
        GEN_MASK_BITS(SSP_DMA_DISABLED, SSP_DMACR_MASK_TXDMAE, 1) \
)

/**
 * load_ssp_default_config - Load default configuration for SSP
 * @pl022: SSP driver private data structure
 */
static void load_ssp_default_config(struct pl022 *pl022)
{
        if (pl022->vendor->pl023) {
                writel(DEFAULT_SSP_REG_CR0_ST_PL023, SSP_CR0(pl022->virtbase));
                writew(DEFAULT_SSP_REG_CR1_ST_PL023, SSP_CR1(pl022->virtbase));
        } else if (pl022->vendor->extended_cr) {
                writel(DEFAULT_SSP_REG_CR0_ST, SSP_CR0(pl022->virtbase));
                writew(DEFAULT_SSP_REG_CR1_ST, SSP_CR1(pl022->virtbase));
        } else {
                writew(DEFAULT_SSP_REG_CR0, SSP_CR0(pl022->virtbase));
                writew(DEFAULT_SSP_REG_CR1, SSP_CR1(pl022->virtbase));
        }
        writew(DEFAULT_SSP_REG_DMACR, SSP_DMACR(pl022->virtbase));
        writew(DEFAULT_SSP_REG_CPSR, SSP_CPSR(pl022->virtbase));
        writew(DISABLE_ALL_INTERRUPTS, SSP_IMSC(pl022->virtbase));
        writew(CLEAR_ALL_INTERRUPTS, SSP_ICR(pl022->virtbase));
}

/**
 * This will write to TX and read from RX according to the parameters
 * set in pl022.
 */
static void readwriter(struct pl022 *pl022)
{

        /*
         * The FIFO depth is different between primecell variants.
         * I believe filling in too much in the FIFO might cause
         * errons in 8bit wide transfers on ARM variants (just 8 words
         * FIFO, means only 8x8 = 64 bits in FIFO) at least.
         *
         * To prevent this issue, the TX FIFO is only filled to the
         * unused RX FIFO fill length, regardless of what the TX
         * FIFO status flag indicates.
         */
        dev_dbg(&pl022->adev->dev,
                "%s, rx: %p, rxend: %p, tx: %p, txend: %p\n",
                __func__, pl022->rx, pl022->rx_end, pl022->tx, pl022->tx_end);

        /* Read as much as you can */
        while ((readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_RNE)
               && (pl022->rx < pl022->rx_end)) {
                switch (pl022->read) {
                case READING_NULL:
                        readw(SSP_DR(pl022->virtbase));
                        break;
                case READING_U8:
                        *(u8 *) (pl022->rx) =
                                readw(SSP_DR(pl022->virtbase)) & 0xFFU;
                        break;
                case READING_U16:
                        *(u16 *) (pl022->rx) =
                                (u16) readw(SSP_DR(pl022->virtbase));
                        break;
                case READING_U32:
                        *(u32 *) (pl022->rx) =
                                readl(SSP_DR(pl022->virtbase));
                        break;
                }
                pl022->rx += (pl022->cur_chip->n_bytes);
                pl022->exp_fifo_level--;
        }
        /*
         * Write as much as possible up to the RX FIFO size
         */
        while ((pl022->exp_fifo_level < pl022->vendor->fifodepth)
               && (pl022->tx < pl022->tx_end)) {
                switch (pl022->write) {
                case WRITING_NULL:
                        writew(0x0, SSP_DR(pl022->virtbase));
                        break;
                case WRITING_U8:
                        writew(*(u8 *) (pl022->tx), SSP_DR(pl022->virtbase));
                        break;
                case WRITING_U16:
                        writew((*(u16 *) (pl022->tx)), SSP_DR(pl022->virtbase));
                        break;
                case WRITING_U32:
                        writel(*(u32 *) (pl022->tx), SSP_DR(pl022->virtbase));
                        break;
                }
                pl022->tx += (pl022->cur_chip->n_bytes);
                pl022->exp_fifo_level++;
                /*
                 * This inner reader takes care of things appearing in the RX
                 * FIFO as we're transmitting. This will happen a lot since the
                 * clock starts running when you put things into the TX FIFO,
                 * and then things are continuously clocked into the RX FIFO.
                 */
                while ((readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_RNE)
                       && (pl022->rx < pl022->rx_end)) {
                        switch (pl022->read) {
                        case READING_NULL:
                                readw(SSP_DR(pl022->virtbase));
                                break;
                        case READING_U8:
                                *(u8 *) (pl022->rx) =
                                        readw(SSP_DR(pl022->virtbase)) & 0xFFU;
                                break;
                        case READING_U16:
                                *(u16 *) (pl022->rx) =
                                        (u16) readw(SSP_DR(pl022->virtbase));
                                break;
                        case READING_U32:
                                *(u32 *) (pl022->rx) =
                                        readl(SSP_DR(pl022->virtbase));
                                break;
                        }
                        pl022->rx += (pl022->cur_chip->n_bytes);
                        pl022->exp_fifo_level--;
                }
        }
        /*
         * When we exit here the TX FIFO should be full and the RX FIFO
         * should be empty
         */
}

/**
 * next_transfer - Move to the Next transfer in the current spi message
 * @pl022: SSP driver private data structure
 *
 * This function moves though the linked list of spi transfers in the
 * current spi message and returns with the state of current spi
 * message i.e whether its last transfer is done(STATE_DONE) or
 * Next transfer is ready(STATE_RUNNING)
 */
static void *next_transfer(struct pl022 *pl022)
{
        struct spi_message *msg = pl022->cur_msg;
        struct spi_transfer *trans = pl022->cur_transfer;

        /* Move to next transfer */
        if (trans->transfer_list.next != &msg->transfers) {
                pl022->cur_transfer =
                    list_entry(trans->transfer_list.next,
                               struct spi_transfer, transfer_list);
                return STATE_RUNNING;
        }
        return STATE_DONE;
}

/*
 * This DMA functionality is only compiled in if we have
 * access to the generic DMA devices/DMA engine.
 */
#ifdef CONFIG_DMA_ENGINE
static void unmap_free_dma_scatter(struct pl022 *pl022)
{
        /* Unmap and free the SG tables */
        dma_unmap_sg(pl022->dma_tx_channel->device->dev, pl022->sgt_tx.sgl,
                     pl022->sgt_tx.nents, DMA_TO_DEVICE);
        dma_unmap_sg(pl022->dma_rx_channel->device->dev, pl022->sgt_rx.sgl,
                     pl022->sgt_rx.nents, DMA_FROM_DEVICE);
        sg_free_table(&pl022->sgt_rx);
        sg_free_table(&pl022->sgt_tx);
}

static void dma_callback(void *data)
{
        struct pl022 *pl022 = data;
        struct spi_message *msg = pl022->cur_msg;

        BUG_ON(!pl022->sgt_rx.sgl);

#ifdef VERBOSE_DEBUG
        /*
         * Optionally dump out buffers to inspect contents, this is
         * good if you want to convince yourself that the loopback
         * read/write contents are the same, when adopting to a new
         * DMA engine.
         */
        {
                struct scatterlist *sg;
                unsigned int i;

                dma_sync_sg_for_cpu(&pl022->adev->dev,
                                    pl022->sgt_rx.sgl,
                                    pl022->sgt_rx.nents,
                                    DMA_FROM_DEVICE);

                for_each_sg(pl022->sgt_rx.sgl, sg, pl022->sgt_rx.nents, i) {
                        dev_dbg(&pl022->adev->dev, "SPI RX SG ENTRY: %d", i);
                        print_hex_dump(KERN_ERR, "SPI RX: ",
                                       DUMP_PREFIX_OFFSET,
                                       16,
                                       1,
                                       sg_virt(sg),
                                       sg_dma_len(sg),
                                       1);
                }
                for_each_sg(pl022->sgt_tx.sgl, sg, pl022->sgt_tx.nents, i) {
                        dev_dbg(&pl022->adev->dev, "SPI TX SG ENTRY: %d", i);
                        print_hex_dump(KERN_ERR, "SPI TX: ",
                                       DUMP_PREFIX_OFFSET,
                                       16,
                                       1,
                                       sg_virt(sg),
                                       sg_dma_len(sg),
                                       1);
                }
        }
#endif

        unmap_free_dma_scatter(pl022);

        /* Update total bytes transferred */
        msg->actual_length += pl022->cur_transfer->len;
        if (pl022->cur_transfer->cs_change)
                pl022_cs_control(pl022, SSP_CHIP_DESELECT);

        /* Move to next transfer */
        msg->state = next_transfer(pl022);
        tasklet_schedule(&pl022->pump_transfers);
}

static void setup_dma_scatter(struct pl022 *pl022,
                              void *buffer,
                              unsigned int length,
                              struct sg_table *sgtab)
{
        struct scatterlist *sg;
        int bytesleft = length;
        void *bufp = buffer;
        int mapbytes;
        int i;

        if (buffer) {
                for_each_sg(sgtab->sgl, sg, sgtab->nents, i) {
                        /*
                         * If there are less bytes left than what fits
                         * in the current page (plus page alignment offset)
                         * we just feed in this, else we stuff in as much
                         * as we can.
                         */
                        if (bytesleft < (PAGE_SIZE - offset_in_page(bufp)))
                                mapbytes = bytesleft;
                        else
                                mapbytes = PAGE_SIZE - offset_in_page(bufp);
                        sg_set_page(sg, virt_to_page(bufp),
                                    mapbytes, offset_in_page(bufp));
                        bufp += mapbytes;
                        bytesleft -= mapbytes;
                        dev_dbg(&pl022->adev->dev,
                                "set RX/TX target page @ %p, %d bytes, %d left\n",
                                bufp, mapbytes, bytesleft);
                }
        } else {
                /* Map the dummy buffer on every page */
                for_each_sg(sgtab->sgl, sg, sgtab->nents, i) {
                        if (bytesleft < PAGE_SIZE)
                                mapbytes = bytesleft;
                        else
                                mapbytes = PAGE_SIZE;
                        sg_set_page(sg, virt_to_page(pl022->dummypage),
                                    mapbytes, 0);
                        bytesleft -= mapbytes;
                        dev_dbg(&pl022->adev->dev,
                                "set RX/TX to dummy page %d bytes, %d left\n",
                                mapbytes, bytesleft);

                }
        }
        BUG_ON(bytesleft);
}

/**
 * configure_dma - configures the channels for the next transfer
 * @pl022: SSP driver's private data structure
 */
static int configure_dma(struct pl022 *pl022)
{
        struct dma_slave_config rx_conf = {
                .src_addr = SSP_DR(pl022->phybase),
                .direction = DMA_DEV_TO_MEM,
                .device_fc = false,
        };
        struct dma_slave_config tx_conf = {
                .dst_addr = SSP_DR(pl022->phybase),
                .direction = DMA_MEM_TO_DEV,
                .device_fc = false,
        };
        unsigned int pages;
        int ret;
        int rx_sglen, tx_sglen;
        struct dma_chan *rxchan = pl022->dma_rx_channel;
        struct dma_chan *txchan = pl022->dma_tx_channel;
        struct dma_async_tx_descriptor *rxdesc;
        struct dma_async_tx_descriptor *txdesc;

        /* Check that the channels are available */
        if (!rxchan || !txchan)
                return -ENODEV;

        /*
         * If supplied, the DMA burstsize should equal the FIFO trigger level.
         * Notice that the DMA engine uses one-to-one mapping. Since we can
         * not trigger on 2 elements this needs explicit mapping rather than
         * calculation.
         */
        switch (pl022->rx_lev_trig) {
        case SSP_RX_1_OR_MORE_ELEM:
                rx_conf.src_maxburst = 1;
                break;
        case SSP_RX_4_OR_MORE_ELEM:
                rx_conf.src_maxburst = 4;
                break;
        case SSP_RX_8_OR_MORE_ELEM:
                rx_conf.src_maxburst = 8;
                break;
        case SSP_RX_16_OR_MORE_ELEM:
                rx_conf.src_maxburst = 16;
                break;
        case SSP_RX_32_OR_MORE_ELEM:
                rx_conf.src_maxburst = 32;
                break;
        default:
                rx_conf.src_maxburst = pl022->vendor->fifodepth >> 1;
                break;
        }

        switch (pl022->tx_lev_trig) {
        case SSP_TX_1_OR_MORE_EMPTY_LOC:
                tx_conf.dst_maxburst = 1;
                break;
        case SSP_TX_4_OR_MORE_EMPTY_LOC:
                tx_conf.dst_maxburst = 4;
                break;
        case SSP_TX_8_OR_MORE_EMPTY_LOC:
                tx_conf.dst_maxburst = 8;
                break;
        case SSP_TX_16_OR_MORE_EMPTY_LOC:
                tx_conf.dst_maxburst = 16;
                break;
        case SSP_TX_32_OR_MORE_EMPTY_LOC:
                tx_conf.dst_maxburst = 32;
                break;
        default:
                tx_conf.dst_maxburst = pl022->vendor->fifodepth >> 1;
                break;
        }

        switch (pl022->read) {
        case READING_NULL:
                /* Use the same as for writing */

                rx_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_UNDEFINED;
                break;
        case READING_U8:
                rx_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
                break;
        case READING_U16:
                rx_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
                break;
        case READING_U32:
                rx_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
                break;
        }

        switch (pl022->write) {
        case WRITING_NULL:
                /* Use the same as for reading */
                tx_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_UNDEFINED;
                break;
        case WRITING_U8:
                tx_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
                break;
        case WRITING_U16:
                tx_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
                break;
        case WRITING_U32:
                tx_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
                break;
        }

        /* SPI pecularity: we need to read and write the same width */
        if (rx_conf.src_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED)
                rx_conf.src_addr_width = tx_conf.dst_addr_width;
        if (tx_conf.dst_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED)
                tx_conf.dst_addr_width = rx_conf.src_addr_width;
        BUG_ON(rx_conf.src_addr_width != tx_conf.dst_addr_width);

        dmaengine_slave_config(rxchan, &rx_conf);
        dmaengine_slave_config(txchan, &tx_conf);

        /* Create sglists for the transfers */
        pages = DIV_ROUND_UP(pl022->cur_transfer->len, PAGE_SIZE);
        dev_dbg(&pl022->adev->dev, "using %d pages for transfer\n", pages);

        ret = sg_alloc_table(&pl022->sgt_rx, pages, GFP_ATOMIC);
        if (ret)
                goto err_alloc_rx_sg;

        ret = sg_alloc_table(&pl022->sgt_tx, pages, GFP_ATOMIC);
        if (ret)
                goto err_alloc_tx_sg;

        /* Fill in the scatterlists for the RX+TX buffers */
        setup_dma_scatter(pl022, pl022->rx,
                          pl022->cur_transfer->len, &pl022->sgt_rx);
        setup_dma_scatter(pl022, pl022->tx,
                          pl022->cur_transfer->len, &pl022->sgt_tx);

        /* Map DMA buffers */
        rx_sglen = dma_map_sg(rxchan->device->dev, pl022->sgt_rx.sgl,
                           pl022->sgt_rx.nents, DMA_FROM_DEVICE);
        if (!rx_sglen)
                goto err_rx_sgmap;

        tx_sglen = dma_map_sg(txchan->device->dev, pl022->sgt_tx.sgl,
                           pl022->sgt_tx.nents, DMA_TO_DEVICE);
        if (!tx_sglen)
                goto err_tx_sgmap;

        /* Send both scatterlists */
        rxdesc = dmaengine_prep_slave_sg(rxchan,
                                      pl022->sgt_rx.sgl,
                                      rx_sglen,
                                      DMA_DEV_TO_MEM,
                                      DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!rxdesc)
                goto err_rxdesc;

        txdesc = dmaengine_prep_slave_sg(txchan,
                                      pl022->sgt_tx.sgl,
                                      tx_sglen,
                                      DMA_MEM_TO_DEV,
                                      DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!txdesc)
                goto err_txdesc;

        /* Put the callback on the RX transfer only, that should finish last */
        rxdesc->callback = dma_callback;
        rxdesc->callback_param = pl022;

        /* Submit and fire RX and TX with TX last so we're ready to read! */
        dmaengine_submit(rxdesc);
        dmaengine_submit(txdesc);
        dma_async_issue_pending(rxchan);
        dma_async_issue_pending(txchan);
        pl022->dma_running = true;

        return 0;

err_txdesc:
        dmaengine_terminate_all(txchan);
err_rxdesc:
        dmaengine_terminate_all(rxchan);
        dma_unmap_sg(txchan->device->dev, pl022->sgt_tx.sgl,
                     pl022->sgt_tx.nents, DMA_TO_DEVICE);
err_tx_sgmap:
        dma_unmap_sg(rxchan->device->dev, pl022->sgt_rx.sgl,
                     pl022->sgt_rx.nents, DMA_FROM_DEVICE);
err_rx_sgmap:
        sg_free_table(&pl022->sgt_tx);
err_alloc_tx_sg:
        sg_free_table(&pl022->sgt_rx);
err_alloc_rx_sg:
        return -ENOMEM;
}

static int pl022_dma_probe(struct pl022 *pl022)
{
        dma_cap_mask_t mask;

        /* Try to acquire a generic DMA engine slave channel */
        dma_cap_zero(mask);
        dma_cap_set(DMA_SLAVE, mask);
        /*
         * We need both RX and TX channels to do DMA, else do none
         * of them.
         */
        pl022->dma_rx_channel = dma_request_channel(mask,
                                            pl022->master_info->dma_filter,
                                            pl022->master_info->dma_rx_param);
        if (!pl022->dma_rx_channel) {
                dev_dbg(&pl022->adev->dev, "no RX DMA channel!\n");
                goto err_no_rxchan;
        }

        pl022->dma_tx_channel = dma_request_channel(mask,
                                            pl022->master_info->dma_filter,
                                            pl022->master_info->dma_tx_param);
        if (!pl022->dma_tx_channel) {
                dev_dbg(&pl022->adev->dev, "no TX DMA channel!\n");
                goto err_no_txchan;
        }

        pl022->dummypage = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!pl022->dummypage)
                goto err_no_dummypage;

        dev_info(&pl022->adev->dev, "setup for DMA on RX %s, TX %s\n",
                 dma_chan_name(pl022->dma_rx_channel),
                 dma_chan_name(pl022->dma_tx_channel));

        return 0;

err_no_dummypage:
        dma_release_channel(pl022->dma_tx_channel);
err_no_txchan:
        dma_release_channel(pl022->dma_rx_channel);
        pl022->dma_rx_channel = NULL;
err_no_rxchan:
        dev_err(&pl022->adev->dev,
                        "Failed to work in dma mode, work without dma!\n");
        return -ENODEV;
}

static int pl022_dma_autoprobe(struct pl022 *pl022)
{
        struct device *dev = &pl022->adev->dev;
        struct dma_chan *chan;
        int err;

        /* automatically configure DMA channels from platform, normally using DT */
        chan = dma_request_slave_channel_reason(dev, "rx");
        if (IS_ERR(chan)) {
                err = PTR_ERR(chan);
                goto err_no_rxchan;
        }

        pl022->dma_rx_channel = chan;

        chan = dma_request_slave_channel_reason(dev, "tx");
        if (IS_ERR(chan)) {
                err = PTR_ERR(chan);
                goto err_no_txchan;
        }

        pl022->dma_tx_channel = chan;

        pl022->dummypage = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!pl022->dummypage) {
                err = -ENOMEM;
                goto err_no_dummypage;
        }

        return 0;

err_no_dummypage:
        dma_release_channel(pl022->dma_tx_channel);
        pl022->dma_tx_channel = NULL;
err_no_txchan:
        dma_release_channel(pl022->dma_rx_channel);
        pl022->dma_rx_channel = NULL;
err_no_rxchan:
        return err;
}
                
static void terminate_dma(struct pl022 *pl022)
{
        struct dma_chan *rxchan = pl022->dma_rx_channel;
        struct dma_chan *txchan = pl022->dma_tx_channel;

        dmaengine_terminate_all(rxchan);
        dmaengine_terminate_all(txchan);
        unmap_free_dma_scatter(pl022);
        pl022->dma_running = false;
}

static void pl022_dma_remove(struct pl022 *pl022)
{
        if (pl022->dma_running)
                terminate_dma(pl022);
        if (pl022->dma_tx_channel)
                dma_release_channel(pl022->dma_tx_channel);
        if (pl022->dma_rx_channel)
                dma_release_channel(pl022->dma_rx_channel);
        kfree(pl022->dummypage);
}

#else
static inline int configure_dma(struct pl022 *pl022)
{
        return -ENODEV;
}

static inline int pl022_dma_autoprobe(struct pl022 *pl022)
{
        return 0;
}

static inline int pl022_dma_probe(struct pl022 *pl022)
{
        return 0;
}

static inline void pl022_dma_remove(struct pl022 *pl022)
{
}
#endif

/**
 * pl022_interrupt_handler - Interrupt handler for SSP controller
 *
 * This function handles interrupts generated for an interrupt based transfer.
 * If a receive overrun (ROR) interrupt is there then we disable SSP, flag the
 * current message's state as STATE_ERROR and schedule the tasklet
 * pump_transfers which will do the postprocessing of the current message by
 * calling giveback(). Otherwise it reads data from RX FIFO till there is no
 * more data, and writes data in TX FIFO till it is not full. If we complete
 * the transfer we move to the next transfer and schedule the tasklet.
 */
static irqreturn_t pl022_interrupt_handler(int irq, void *dev_id)
{
        struct pl022 *pl022 = dev_id;
        struct spi_message *msg = pl022->cur_msg;
        u16 irq_status = 0;

        if (unlikely(!msg)) {
                dev_err(&pl022->adev->dev,
                        "bad message state in interrupt handler");
                /* Never fail */
                return IRQ_HANDLED;
        }

        /* Read the Interrupt Status Register */
        irq_status = readw(SSP_MIS(pl022->virtbase));

        if (unlikely(!irq_status))
                return IRQ_NONE;

        /*
         * This handles the FIFO interrupts, the timeout
         * interrupts are flatly ignored, they cannot be
         * trusted.
         */
        if (unlikely(irq_status & SSP_MIS_MASK_RORMIS)) {
                /*
                 * Overrun interrupt - bail out since our Data has been
                 * corrupted
                 */
                dev_err(&pl022->adev->dev, "FIFO overrun\n");
                if (readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_RFF)
                        dev_err(&pl022->adev->dev,
                                "RXFIFO is full\n");

                /*
                 * Disable and clear interrupts, disable SSP,
                 * mark message with bad status so it can be
                 * retried.
                 */
                writew(DISABLE_ALL_INTERRUPTS,
                       SSP_IMSC(pl022->virtbase));
                writew(CLEAR_ALL_INTERRUPTS, SSP_ICR(pl022->virtbase));
                writew((readw(SSP_CR1(pl022->virtbase)) &
                        (~SSP_CR1_MASK_SSE)), SSP_CR1(pl022->virtbase));
                msg->state = STATE_ERROR;

                /* Schedule message queue handler */
                tasklet_schedule(&pl022->pump_transfers);
                return IRQ_HANDLED;
        }

        readwriter(pl022);

        if (pl022->tx == pl022->tx_end) {
                /* Disable Transmit interrupt, enable receive interrupt */
                writew((readw(SSP_IMSC(pl022->virtbase)) &
                       ~SSP_IMSC_MASK_TXIM) | SSP_IMSC_MASK_RXIM,
                       SSP_IMSC(pl022->virtbase));
        }

        /*
         * Since all transactions must write as much as shall be read,
         * we can conclude the entire transaction once RX is complete.
         * At this point, all TX will always be finished.
         */
        if (pl022->rx >= pl022->rx_end) {
                writew(DISABLE_ALL_INTERRUPTS,
                       SSP_IMSC(pl022->virtbase));
                writew(CLEAR_ALL_INTERRUPTS, SSP_ICR(pl022->virtbase));
                if (unlikely(pl022->rx > pl022->rx_end)) {
                        dev_warn(&pl022->adev->dev, "read %u surplus "
                                 "bytes (did you request an odd "
                                 "number of bytes on a 16bit bus?)\n",
                                 (u32) (pl022->rx - pl022->rx_end));
                }
                /* Update total bytes transferred */
                msg->actual_length += pl022->cur_transfer->len;
                if (pl022->cur_transfer->cs_change)
                        pl022_cs_control(pl022, SSP_CHIP_DESELECT);
                /* Move to next transfer */
                msg->state = next_transfer(pl022);
                tasklet_schedule(&pl022->pump_transfers);
                return IRQ_HANDLED;
        }

        return IRQ_HANDLED;
}

/**
 * This sets up the pointers to memory for the next message to
 * send out on the SPI bus.
 */
static int set_up_next_transfer(struct pl022 *pl022,
                                struct spi_transfer *transfer)
{
        int residue;

        /* Sanity check the message for this bus width */
        residue = pl022->cur_transfer->len % pl022->cur_chip->n_bytes;
        if (unlikely(residue != 0)) {
                dev_err(&pl022->adev->dev,
                        "message of %u bytes to transmit but the current "
                        "chip bus has a data width of %u bytes!\n",
                        pl022->cur_transfer->len,
                        pl022->cur_chip->n_bytes);
                dev_err(&pl022->adev->dev, "skipping this message\n");
                return -EIO;
        }
        pl022->tx = (void *)transfer->tx_buf;
        pl022->tx_end = pl022->tx + pl022->cur_transfer->len;
        pl022->rx = (void *)transfer->rx_buf;
        pl022->rx_end = pl022->rx + pl022->cur_transfer->len;
        pl022->write =
            pl022->tx ? pl022->cur_chip->write : WRITING_NULL;
        pl022->read = pl022->rx ? pl022->cur_chip->read : READING_NULL;
        return 0;
}

/**
 * pump_transfers - Tasklet function which schedules next transfer
 * when running in interrupt or DMA transfer mode.
 * @data: SSP driver private data structure
 *
 */
static void pump_transfers(unsigned long data)
{
        struct pl022 *pl022 = (struct pl022 *) data;
        struct spi_message *message = NULL;
        struct spi_transfer *transfer = NULL;
        struct spi_transfer *previous = NULL;

        /* Get current state information */
        message = pl022->cur_msg;
        transfer = pl022->cur_transfer;

        /* Handle for abort */
        if (message->state == STATE_ERROR) {
                message->status = -EIO;
                giveback(pl022);
                return;
        }

        /* Handle end of message */
        if (message->state == STATE_DONE) {
                message->status = 0;
                giveback(pl022);
                return;
        }

        /* Delay if requested at end of transfer before CS change */
        if (message->state == STATE_RUNNING) {
                previous = list_entry(transfer->transfer_list.prev,
                                        struct spi_transfer,
                                        transfer_list);
                if (previous->delay_usecs)
                        /*
                         * FIXME: This runs in interrupt context.
                         * Is this really smart?
                         */
                        udelay(previous->delay_usecs);

                /* Reselect chip select only if cs_change was requested */
                if (previous->cs_change)
                        pl022_cs_control(pl022, SSP_CHIP_SELECT);
        } else {
                /* STATE_START */
                message->state = STATE_RUNNING;
        }

        if (set_up_next_transfer(pl022, transfer)) {
                message->state = STATE_ERROR;
                message->status = -EIO;
                giveback(pl022);
                return;
        }
        /* Flush the FIFOs and let's go! */
        flush(pl022);

        if (pl022->cur_chip->enable_dma) {
                if (configure_dma(pl022)) {
                        dev_dbg(&pl022->adev->dev,
                                "configuration of DMA failed, fall back to interrupt mode\n");
                        goto err_config_dma;
                }
                return;
        }

err_config_dma:
        /* enable all interrupts except RX */
        writew(ENABLE_ALL_INTERRUPTS & ~SSP_IMSC_MASK_RXIM, SSP_IMSC(pl022->virtbase));
}

static void do_interrupt_dma_transfer(struct pl022 *pl022)
{
        /*
         * Default is to enable all interrupts except RX -
         * this will be enabled once TX is complete
         */
        u32 irqflags = (u32)(ENABLE_ALL_INTERRUPTS & ~SSP_IMSC_MASK_RXIM);

        /* Enable target chip, if not already active */
        if (!pl022->next_msg_cs_active)
                pl022_cs_control(pl022, SSP_CHIP_SELECT);

        if (set_up_next_transfer(pl022, pl022->cur_transfer)) {
                /* Error path */
                pl022->cur_msg->state = STATE_ERROR;
                pl022->cur_msg->status = -EIO;
                giveback(pl022);
                return;
        }
        /* If we're using DMA, set up DMA here */
        if (pl022->cur_chip->enable_dma) {
                /* Configure DMA transfer */
                if (configure_dma(pl022)) {
                        dev_dbg(&pl022->adev->dev,
                                "configuration of DMA failed, fall back to interrupt mode\n");
                        goto err_config_dma;
                }
                /* Disable interrupts in DMA mode, IRQ from DMA controller */
                irqflags = DISABLE_ALL_INTERRUPTS;
        }
err_config_dma:
        /* Enable SSP, turn on interrupts */
        writew((readw(SSP_CR1(pl022->virtbase)) | SSP_CR1_MASK_SSE),
               SSP_CR1(pl022->virtbase));
        writew(irqflags, SSP_IMSC(pl022->virtbase));
}

static void do_polling_transfer(struct pl022 *pl022)
{
        struct spi_message *message = NULL;
        struct spi_transfer *transfer = NULL;
        struct spi_transfer *previous = NULL;
        struct chip_data *chip;
        unsigned long time, timeout;

        chip = pl022->cur_chip;
        message = pl022->cur_msg;

        while (message->state != STATE_DONE) {
                /* Handle for abort */
                if (message->state == STATE_ERROR)
                        break;
                transfer = pl022->cur_transfer;

                /* Delay if requested at end of transfer */
                if (message->state == STATE_RUNNING) {
                        previous =
                            list_entry(transfer->transfer_list.prev,
                                       struct spi_transfer, transfer_list);
                        if (previous->delay_usecs)
                                udelay(previous->delay_usecs);
                        if (previous->cs_change)
                                pl022_cs_control(pl022, SSP_CHIP_SELECT);
                } else {
                        /* STATE_START */
                        message->state = STATE_RUNNING;
                        if (!pl022->next_msg_cs_active)
                                pl022_cs_control(pl022, SSP_CHIP_SELECT);
                }

                /* Configuration Changing Per Transfer */
                if (set_up_next_transfer(pl022, transfer)) {
                        /* Error path */
                        message->state = STATE_ERROR;
                        break;
                }
                /* Flush FIFOs and enable SSP */
                flush(pl022);
                writew((readw(SSP_CR1(pl022->virtbase)) | SSP_CR1_MASK_SSE),
                       SSP_CR1(pl022->virtbase));

                dev_dbg(&pl022->adev->dev, "polling transfer ongoing ...\n");

                timeout = jiffies + msecs_to_jiffies(SPI_POLLING_TIMEOUT);
                while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end) {
                        time = jiffies;
                        readwriter(pl022);
                        if (time_after(time, timeout)) {
                                dev_warn(&pl022->adev->dev,
                                "%s: timeout!\n", __func__);
                                message->state = STATE_ERROR;
                                goto out;
                        }
                        cpu_relax();
                }

                /* Update total byte transferred */
                message->actual_length += pl022->cur_transfer->len;
                if (pl022->cur_transfer->cs_change)
                        pl022_cs_control(pl022, SSP_CHIP_DESELECT);
                /* Move to next transfer */
                message->state = next_transfer(pl022);
        }
out:
        /* Handle end of message */
        if (message->state == STATE_DONE)
                message->status = 0;
        else
                message->status = -EIO;

        giveback(pl022);
        return;
}

static int pl022_transfer_one_message(struct spi_master *master,
                                      struct spi_message *msg)
{
        struct pl022 *pl022 = spi_master_get_devdata(master);

        /* Initial message state */
        pl022->cur_msg = msg;
        msg->state = STATE_START;

        pl022->cur_transfer = list_entry(msg->transfers.next,
                                         struct spi_transfer, transfer_list);

        /* Setup the SPI using the per chip configuration */
        pl022->cur_chip = spi_get_ctldata(msg->spi);
        pl022->cur_cs = pl022->chipselects[msg->spi->chip_select];

        restore_state(pl022);
        flush(pl022);

        if (pl022->cur_chip->xfer_type == POLLING_TRANSFER)
                do_polling_transfer(pl022);
        else
                do_interrupt_dma_transfer(pl022);

        return 0;
}

static int pl022_unprepare_transfer_hardware(struct spi_master *master)
{
        struct pl022 *pl022 = spi_master_get_devdata(master);

        /* nothing more to do - disable spi/ssp and power off */
        writew((readw(SSP_CR1(pl022->virtbase)) &
                (~SSP_CR1_MASK_SSE)), SSP_CR1(pl022->virtbase));

        return 0;
}

static int verify_controller_parameters(struct pl022 *pl022,
                                struct pl022_config_chip const *chip_info)
{
        if ((chip_info->iface < SSP_INTERFACE_MOTOROLA_SPI)
            || (chip_info->iface > SSP_INTERFACE_UNIDIRECTIONAL)) {
                dev_err(&pl022->adev->dev,
                        "interface is configured incorrectly\n");
                return -EINVAL;
        }
        if ((chip_info->iface == SSP_INTERFACE_UNIDIRECTIONAL) &&
            (!pl022->vendor->unidir)) {
                dev_err(&pl022->adev->dev,
                        "unidirectional mode not supported in this "
                        "hardware version\n");
                return -EINVAL;
        }
        if ((chip_info->hierarchy != SSP_MASTER)
            && (chip_info->hierarchy != SSP_SLAVE)) {
                dev_err(&pl022->adev->dev,
                        "hierarchy is configured incorrectly\n");
                return -EINVAL;
        }
        if ((chip_info->com_mode != INTERRUPT_TRANSFER)
            && (chip_info->com_mode != DMA_TRANSFER)
            && (chip_info->com_mode != POLLING_TRANSFER)) {
                dev_err(&pl022->adev->dev,
                        "Communication mode is configured incorrectly\n");
                return -EINVAL;
        }
        switch (chip_info->rx_lev_trig) {
        case SSP_RX_1_OR_MORE_ELEM:
        case SSP_RX_4_OR_MORE_ELEM:
        case SSP_RX_8_OR_MORE_ELEM:
                /* These are always OK, all variants can handle this */
                break;
        case SSP_RX_16_OR_MORE_ELEM:
                if (pl022->vendor->fifodepth < 16) {
                        dev_err(&pl022->adev->dev,
                        "RX FIFO Trigger Level is configured incorrectly\n");
                        return -EINVAL;
                }
                break;
        case SSP_RX_32_OR_MORE_ELEM:
                if (pl022->vendor->fifodepth < 32) {
                        dev_err(&pl022->adev->dev,
                        "RX FIFO Trigger Level is configured incorrectly\n");
                        return -EINVAL;
                }
                break;
        default:
                dev_err(&pl022->adev->dev,
                        "RX FIFO Trigger Level is configured incorrectly\n");
                return -EINVAL;
        }
        switch (chip_info->tx_lev_trig) {
        case SSP_TX_1_OR_MORE_EMPTY_LOC:
        case SSP_TX_4_OR_MORE_EMPTY_LOC:
        case SSP_TX_8_OR_MORE_EMPTY_LOC:
                /* These are always OK, all variants can handle this */
                break;
        case SSP_TX_16_OR_MORE_EMPTY_LOC:
                if (pl022->vendor->fifodepth < 16) {
                        dev_err(&pl022->adev->dev,
                        "TX FIFO Trigger Level is configured incorrectly\n");
                        return -EINVAL;
                }
                break;
        case SSP_TX_32_OR_MORE_EMPTY_LOC:
                if (pl022->vendor->fifodepth < 32) {
                        dev_err(&pl022->adev->dev,
                        "TX FIFO Trigger Level is configured incorrectly\n");
                        return -EINVAL;
                }
                break;
        default:
                dev_err(&pl022->adev->dev,
                        "TX FIFO Trigger Level is configured incorrectly\n");
                return -EINVAL;
        }
        if (chip_info->iface == SSP_INTERFACE_NATIONAL_MICROWIRE) {
                if ((chip_info->ctrl_len < SSP_BITS_4)
                    || (chip_info->ctrl_len > SSP_BITS_32)) {
                        dev_err(&pl022->adev->dev,
                                "CTRL LEN is configured incorrectly\n");
                        return -EINVAL;
                }
                if ((chip_info->wait_state != SSP_MWIRE_WAIT_ZERO)
                    && (chip_info->wait_state != SSP_MWIRE_WAIT_ONE)) {
                        dev_err(&pl022->adev->dev,
                                "Wait State is configured incorrectly\n");
                        return -EINVAL;
                }
                /* Half duplex is only available in the ST Micro version */
                if (pl022->vendor->extended_cr) {
                        if ((chip_info->duplex !=
                             SSP_MICROWIRE_CHANNEL_FULL_DUPLEX)
                            && (chip_info->duplex !=
                                SSP_MICROWIRE_CHANNEL_HALF_DUPLEX)) {
                                dev_err(&pl022->adev->dev,
                                        "Microwire duplex mode is configured incorrectly\n");
                                return -EINVAL;
                        }
                } else {
                        if (chip_info->duplex != SSP_MICROWIRE_CHANNEL_FULL_DUPLEX)
                                dev_err(&pl022->adev->dev,
                                        "Microwire half duplex mode requested,"
                                        " but this is only available in the"
                                        " ST version of PL022\n");
                        return -EINVAL;
                }
        }
        return 0;
}

static inline u32 spi_rate(u32 rate, u16 cpsdvsr, u16 scr)
{
        return rate / (cpsdvsr * (1 + scr));
}

static int calculate_effective_freq(struct pl022 *pl022, int freq, struct
                                    ssp_clock_params * clk_freq)
{
        /* Lets calculate the frequency parameters */
        u16 cpsdvsr = CPSDVR_MIN, scr = SCR_MIN;
        u32 rate, max_tclk, min_tclk, best_freq = 0, best_cpsdvsr = 0,
                best_scr = 0, tmp, found = 0;

        rate = clk_get_rate(pl022->clk);
        /* cpsdvscr = 2 & scr 0 */
        max_tclk = spi_rate(rate, CPSDVR_MIN, SCR_MIN);
        /* cpsdvsr = 254 & scr = 255 */
        min_tclk = spi_rate(rate, CPSDVR_MAX, SCR_MAX);

        if (freq > max_tclk)
                dev_warn(&pl022->adev->dev,
                        "Max speed that can be programmed is %d Hz, you requested %d\n",
                        max_tclk, freq);

        if (freq < min_tclk) {
                dev_err(&pl022->adev->dev,
                        "Requested frequency: %d Hz is less than minimum possible %d Hz\n",
                        freq, min_tclk);
                return -EINVAL;
        }

        /*
         * best_freq will give closest possible available rate (<= requested
         * freq) for all values of scr & cpsdvsr.
         */
        while ((cpsdvsr <= CPSDVR_MAX) && !found) {
                while (scr <= SCR_MAX) {
                        tmp = spi_rate(rate, cpsdvsr, scr);

                        if (tmp > freq) {
                                /* we need lower freq */
                                scr++;
                                continue;
                        }

                        /*
                         * If found exact value, mark found and break.
                         * If found more closer value, update and break.
                         */
                        if (tmp > best_freq) {
                                best_freq = tmp;
                                best_cpsdvsr = cpsdvsr;
                                best_scr = scr;

                                if (tmp == freq)
                                        found = 1;
                        }
                        /*
                         * increased scr will give lower rates, which are not
                         * required
                         */
                        break;
                }
                cpsdvsr += 2;
                scr = SCR_MIN;
        }

        WARN(!best_freq, "pl022: Matching cpsdvsr and scr not found for %d Hz rate \n",
                        freq);

        clk_freq->cpsdvsr = (u8) (best_cpsdvsr & 0xFF);
        clk_freq->scr = (u8) (best_scr & 0xFF);
        dev_dbg(&pl022->adev->dev,
                "SSP Target Frequency is: %u, Effective Frequency is %u\n",
                freq, best_freq);
        dev_dbg(&pl022->adev->dev, "SSP cpsdvsr = %d, scr = %d\n",
                clk_freq->cpsdvsr, clk_freq->scr);

        return 0;
}

/*
 * A piece of default chip info unless the platform
 * supplies it.
 */
static const struct pl022_config_chip pl022_default_chip_info = {
        .com_mode = POLLING_TRANSFER,
        .iface = SSP_INTERFACE_MOTOROLA_SPI,
        .hierarchy = SSP_SLAVE,
        .slave_tx_disable = DO_NOT_DRIVE_TX,
        .rx_lev_trig = SSP_RX_1_OR_MORE_ELEM,
        .tx_lev_trig = SSP_TX_1_OR_MORE_EMPTY_LOC,
        .ctrl_len = SSP_BITS_8,
        .wait_state = SSP_MWIRE_WAIT_ZERO,
        .duplex = SSP_MICROWIRE_CHANNEL_FULL_DUPLEX,
        .cs_control = null_cs_control,
};

/**
 * pl022_setup - setup function registered to SPI master framework
 * @spi: spi device which is requesting setup
 *
 * This function is registered to the SPI framework for this SPI master
 * controller. If it is the first time when setup is called by this device,
 * this function will initialize the runtime state for this chip and save
 * the same in the device structure. Else it will update the runtime info
 * with the updated chip info. Nothing is really being written to the
 * controller hardware here, that is not done until the actual transfer
 * commence.
 */
static int pl022_setup(struct spi_device *spi)
{
        struct pl022_config_chip const *chip_info;
        struct pl022_config_chip chip_info_dt;
        struct chip_data *chip;
        struct ssp_clock_params clk_freq = { .cpsdvsr = 0, .scr = 0};
        int status = 0;
        struct pl022 *pl022 = spi_master_get_devdata(spi->master);
        unsigned int bits = spi->bits_per_word;
        u32 tmp;
        struct device_node *np = spi->dev.of_node;

        if (!spi->max_speed_hz)
                return -EINVAL;

        /* Get controller_state if one is supplied */
        chip = spi_get_ctldata(spi);

        if (chip == NULL) {
                chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
                if (!chip)
                        return -ENOMEM;
                dev_dbg(&spi->dev,
                        "allocated memory for controller's runtime state\n");
        }

        /* Get controller data if one is supplied */
        chip_info = spi->controller_data;

        if (chip_info == NULL) {
                if (np) {
                        chip_info_dt = pl022_default_chip_info;

                        chip_info_dt.hierarchy = SSP_MASTER;
                        of_property_read_u32(np, "pl022,interface",
                                &chip_info_dt.iface);
                        of_property_read_u32(np, "pl022,com-mode",
                                &chip_info_dt.com_mode);
                        of_property_read_u32(np, "pl022,rx-level-trig",
                                &chip_info_dt.rx_lev_trig);
                        of_property_read_u32(np, "pl022,tx-level-trig",
                                &chip_info_dt.tx_lev_trig);
                        of_property_read_u32(np, "pl022,ctrl-len",
                                &chip_info_dt.ctrl_len);
                        of_property_read_u32(np, "pl022,wait-state",
                                &chip_info_dt.wait_state);
                        of_property_read_u32(np, "pl022,duplex",
                                &chip_info_dt.duplex);

                        chip_info = &chip_info_dt;
                } else {
                        chip_info = &pl022_default_chip_info;
                        /* spi_board_info.controller_data not is supplied */
                        dev_dbg(&spi->dev,
                                "using default controller_data settings\n");
                }
        } else
                dev_dbg(&spi->dev,
                        "using user supplied controller_data settings\n");

        /*
         * We can override with custom divisors, else we use the board
         * frequency setting
         */
        if ((0 == chip_info->clk_freq.cpsdvsr)
            && (0 == chip_info->clk_freq.scr)) {
                status = calculate_effective_freq(pl022,
                                                  spi->max_speed_hz,
                                                  &clk_freq);
                if (status < 0)
                        goto err_config_params;
        } else {
                memcpy(&clk_freq, &chip_info->clk_freq, sizeof(clk_freq));
                if ((clk_freq.cpsdvsr % 2) != 0)
                        clk_freq.cpsdvsr =
                                clk_freq.cpsdvsr - 1;
        }
        if ((clk_freq.cpsdvsr < CPSDVR_MIN)
            || (clk_freq.cpsdvsr > CPSDVR_MAX)) {
                status = -EINVAL;
                dev_err(&spi->dev,
                        "cpsdvsr is configured incorrectly\n");
                goto err_config_params;
        }

        status = verify_controller_parameters(pl022, chip_info);
        if (status) {
                dev_err(&spi->dev, "controller data is incorrect");
                goto err_config_params;
        }

        pl022->rx_lev_trig = chip_info->rx_lev_trig;
        pl022->tx_lev_trig = chip_info->tx_lev_trig;

        /* Now set controller state based on controller data */
        chip->xfer_type = chip_info->com_mode;
        if (!chip_info->cs_control) {
                chip->cs_control = null_cs_control;
                if (!gpio_is_valid(pl022->chipselects[spi->chip_select]))
                        dev_warn(&spi->dev,
                                 "invalid chip select\n");
        } else
                chip->cs_control = chip_info->cs_control;

        /* Check bits per word with vendor specific range */
        if ((bits <= 3) || (bits > pl022->vendor->max_bpw)) {
                status = -ENOTSUPP;
                dev_err(&spi->dev, "illegal data size for this controller!\n");
                dev_err(&spi->dev, "This controller can only handle 4 <= n <= %d bit words\n",
                                pl022->vendor->max_bpw);
                goto err_config_params;
        } else if (bits <= 8) {
                dev_dbg(&spi->dev, "4 <= n <=8 bits per word\n");
                chip->n_bytes = 1;
                chip->read = READING_U8;
                chip->write = WRITING_U8;
        } else if (bits <= 16) {
                dev_dbg(&spi->dev, "9 <= n <= 16 bits per word\n");
                chip->n_bytes = 2;
                chip->read = READING_U16;
                chip->write = WRITING_U16;
        } else {
                dev_dbg(&spi->dev, "17 <= n <= 32 bits per word\n");
                chip->n_bytes = 4;
                chip->read = READING_U32;
                chip->write = WRITING_U32;
        }

        /* Now Initialize all register settings required for this chip */
        chip->cr0 = 0;
        chip->cr1 = 0;
        chip->dmacr = 0;
        chip->cpsr = 0;
        if ((chip_info->com_mode == DMA_TRANSFER)
            && ((pl022->master_info)->enable_dma)) {
                chip->enable_dma = true;
                dev_dbg(&spi->dev, "DMA mode set in controller state\n");
                SSP_WRITE_BITS(chip->dmacr, SSP_DMA_ENABLED,
                               SSP_DMACR_MASK_RXDMAE, 0);
                SSP_WRITE_BITS(chip->dmacr, SSP_DMA_ENABLED,
                               SSP_DMACR_MASK_TXDMAE, 1);
        } else {
                chip->enable_dma = false;
                dev_dbg(&spi->dev, "DMA mode NOT set in controller state\n");
                SSP_WRITE_BITS(chip->dmacr, SSP_DMA_DISABLED,
                               SSP_DMACR_MASK_RXDMAE, 0);
                SSP_WRITE_BITS(chip->dmacr, SSP_DMA_DISABLED,
                               SSP_DMACR_MASK_TXDMAE, 1);
        }

        chip->cpsr = clk_freq.cpsdvsr;

        /* Special setup for the ST micro extended control registers */
        if (pl022->vendor->extended_cr) {
                u32 etx;

                if (pl022->vendor->pl023) {
                        /* These bits are only in the PL023 */
                        SSP_WRITE_BITS(chip->cr1, chip_info->clkdelay,
                                       SSP_CR1_MASK_FBCLKDEL_ST, 13);
                } else {
                        /* These bits are in the PL022 but not PL023 */
                        SSP_WRITE_BITS(chip->cr0, chip_info->duplex,
                                       SSP_CR0_MASK_HALFDUP_ST, 5);
                        SSP_WRITE_BITS(chip->cr0, chip_info->ctrl_len,
                                       SSP_CR0_MASK_CSS_ST, 16);
                        SSP_WRITE_BITS(chip->cr0, chip_info->iface,
                                       SSP_CR0_MASK_FRF_ST, 21);
                        SSP_WRITE_BITS(chip->cr1, chip_info->wait_state,
                                       SSP_CR1_MASK_MWAIT_ST, 6);
                }
                SSP_WRITE_BITS(chip->cr0, bits - 1,
                               SSP_CR0_MASK_DSS_ST, 0);

                if (spi->mode & SPI_LSB_FIRST) {
                        tmp = SSP_RX_LSB;
                        etx = SSP_TX_LSB;
                } else {
                        tmp = SSP_RX_MSB;
                        etx = SSP_TX_MSB;
                }
                SSP_WRITE_BITS(chip->cr1, tmp, SSP_CR1_MASK_RENDN_ST, 4);
                SSP_WRITE_BITS(chip->cr1, etx, SSP_CR1_MASK_TENDN_ST, 5);
                SSP_WRITE_BITS(chip->cr1, chip_info->rx_lev_trig,
                               SSP_CR1_MASK_RXIFLSEL_ST, 7);
                SSP_WRITE_BITS(chip->cr1, chip_info->tx_lev_trig,
                               SSP_CR1_MASK_TXIFLSEL_ST, 10);
        } else {
                SSP_WRITE_BITS(chip->cr0, bits - 1,
                               SSP_CR0_MASK_DSS, 0);
                SSP_WRITE_BITS(chip->cr0, chip_info->iface,
                               SSP_CR0_MASK_FRF, 4);
        }

        /* Stuff that is common for all versions */
        if (spi->mode & SPI_CPOL)
                tmp = SSP_CLK_POL_IDLE_HIGH;
        else
                tmp = SSP_CLK_POL_IDLE_LOW;
        SSP_WRITE_BITS(chip->cr0, tmp, SSP_CR0_MASK_SPO, 6);

        if (spi->mode & SPI_CPHA)
                tmp = SSP_CLK_SECOND_EDGE;
        else
                tmp = SSP_CLK_FIRST_EDGE;
        SSP_WRITE_BITS(chip->cr0, tmp, SSP_CR0_MASK_SPH, 7);

        SSP_WRITE_BITS(chip->cr0, clk_freq.scr, SSP_CR0_MASK_SCR, 8);
        /* Loopback is available on all versions except PL023 */
        if (pl022->vendor->loopback) {
                if (spi->mode & SPI_LOOP)
                        tmp = LOOPBACK_ENABLED;
                else
                        tmp = LOOPBACK_DISABLED;
                SSP_WRITE_BITS(chip->cr1, tmp, SSP_CR1_MASK_LBM, 0);
        }
        SSP_WRITE_BITS(chip->cr1, SSP_DISABLED, SSP_CR1_MASK_SSE, 1);
        SSP_WRITE_BITS(chip->cr1, chip_info->hierarchy, SSP_CR1_MASK_MS, 2);
        SSP_WRITE_BITS(chip->cr1, chip_info->slave_tx_disable, SSP_CR1_MASK_SOD,
                3);

        /* Save controller_state */
        spi_set_ctldata(spi, chip);
        return status;
 err_config_params:
        spi_set_ctldata(spi, NULL);
        kfree(chip);
        return status;
}

/**
 * pl022_cleanup - cleanup function registered to SPI master framework
 * @spi: spi device which is requesting cleanup
 *
 * This function is registered to the SPI framework for this SPI master
 * controller. It will free the runtime state of chip.
 */
static void pl022_cleanup(struct spi_device *spi)
{
        struct chip_data *chip = spi_get_ctldata(spi);

        spi_set_ctldata(spi, NULL);
        kfree(chip);
}

static struct pl022_ssp_controller *
pl022_platform_data_dt_get(struct device *dev)
{
        struct device_node *np = dev->of_node;
        struct pl022_ssp_controller *pd;
        u32 tmp = 0;

        if (!np) {
                dev_err(dev, "no dt node defined\n");
                return NULL;
        }

        pd = devm_kzalloc(dev, sizeof(struct pl022_ssp_controller), GFP_KERNEL);
        if (!pd)
                return NULL;

        pd->bus_id = -1;
        pd->enable_dma = 1;
        of_property_read_u32(np, "num-cs", &tmp);
        pd->num_chipselect = tmp;
        of_property_read_u32(np, "pl022,autosuspend-delay",
                             &pd->autosuspend_delay);
        pd->rt = of_property_read_bool(np, "pl022,rt");

        return pd;
}

static int pl022_probe(struct amba_device *adev, const struct amba_id *id)
{
        struct device *dev = &adev->dev;
        struct pl022_ssp_controller *platform_info =
                        dev_get_platdata(&adev->dev);
        struct spi_master *master;
        struct pl022 *pl022 = NULL;     /*Data for this driver */
        struct device_node *np = adev->dev.of_node;
        int status = 0, i, num_cs;

        dev_info(&adev->dev,
                 "ARM PL022 driver, device ID: 0x%08x\n", adev->periphid);
        if (!platform_info && IS_ENABLED(CONFIG_OF))
                platform_info = pl022_platform_data_dt_get(dev);

        if (!platform_info) {
                dev_err(dev, "probe: no platform data defined\n");
                return -ENODEV;
        }

        if (platform_info->num_chipselect) {
                num_cs = platform_info->num_chipselect;
        } else {
                dev_err(dev, "probe: no chip select defined\n");
                return -ENODEV;
        }

        /* Allocate master with space for data */
        master = spi_alloc_master(dev, sizeof(struct pl022));
        if (master == NULL) {
                dev_err(&adev->dev, "probe - cannot alloc SPI master\n");
                return -ENOMEM;
        }

        pl022 = spi_master_get_devdata(master);
        pl022->master = master;
        pl022->master_info = platform_info;
        pl022->adev = adev;
        pl022->vendor = id->data;
        pl022->chipselects = devm_kzalloc(dev, num_cs * sizeof(int),
                                          GFP_KERNEL);
        if (!pl022->chipselects) {
                status = -ENOMEM;
                goto err_no_mem;
        }

        /*
         * Bus Number Which has been Assigned to this SSP controller
         * on this board
         */
        master->bus_num = platform_info->bus_id;
        master->num_chipselect = num_cs;
        master->cleanup = pl022_cleanup;
        master->setup = pl022_setup;
        master->auto_runtime_pm = true;
        master->transfer_one_message = pl022_transfer_one_message;
        master->unprepare_transfer_hardware = pl022_unprepare_transfer_hardware;
        master->rt = platform_info->rt;
        master->dev.of_node = dev->of_node;

        if (platform_info->num_chipselect && platform_info->chipselects) {
                for (i = 0; i < num_cs; i++)
                        pl022->chipselects[i] = platform_info->chipselects[i];
        } else if (pl022->vendor->internal_cs_ctrl) {
                for (i = 0; i < num_cs; i++)
                        pl022->chipselects[i] = i;
        } else if (IS_ENABLED(CONFIG_OF)) {
                for (i = 0; i < num_cs; i++) {
                        int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);

                        if (cs_gpio == -EPROBE_DEFER) {
                                status = -EPROBE_DEFER;
                                goto err_no_gpio;
                        }

                        pl022->chipselects[i] = cs_gpio;

                        if (gpio_is_valid(cs_gpio)) {
                                if (devm_gpio_request(dev, cs_gpio, "ssp-pl022"))
                                        dev_err(&adev->dev,
                                                "could not request %d gpio\n",
                                                cs_gpio);
                                else if (gpio_direction_output(cs_gpio, 1))
                                        dev_err(&adev->dev,
                                                "could not set gpio %d as output\n",
                                                cs_gpio);
                        }
                }
        }

        /*
         * Supports mode 0-3, loopback, and active low CS. Transfers are
         * always MS bit first on the original pl022.
         */
        master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP;
        if (pl022->vendor->extended_cr)
                master->mode_bits |= SPI_LSB_FIRST;

        dev_dbg(&adev->dev, "BUSNO: %d\n", master->bus_num);

        status = amba_request_regions(adev, NULL);
        if (status)
                goto err_no_ioregion;

        pl022->phybase = adev->res.start;
        pl022->virtbase = devm_ioremap(dev, adev->res.start,
                                       resource_size(&adev->res));
        if (pl022->virtbase == NULL) {
                status = -ENOMEM;
                goto err_no_ioremap;
        }
        dev_info(&adev->dev, "mapped registers from %pa to %p\n",
                &adev->res.start, pl022->virtbase);

        pl022->clk = devm_clk_get(&adev->dev, NULL);
        if (IS_ERR(pl022->clk)) {
                status = PTR_ERR(pl022->clk);
                dev_err(&adev->dev, "could not retrieve SSP/SPI bus clock\n");
                goto err_no_clk;
        }

        status = clk_prepare_enable(pl022->clk);
        if (status) {
                dev_err(&adev->dev, "could not enable SSP/SPI bus clock\n");
                goto err_no_clk_en;
        }

        /* Initialize transfer pump */
        tasklet_init(&pl022->pump_transfers, pump_transfers,
                     (unsigned long)pl022);

        /* Disable SSP */
        writew((readw(SSP_CR1(pl022->virtbase)) & (~SSP_CR1_MASK_SSE)),
               SSP_CR1(pl022->virtbase));
        load_ssp_default_config(pl022);

        status = devm_request_irq(dev, adev->irq[0], pl022_interrupt_handler,
                                  0, "pl022", pl022);
        if (status < 0) {
                dev_err(&adev->dev, "probe - cannot get IRQ (%d)\n", status);
                goto err_no_irq;
        }

        /* Get DMA channels, try autoconfiguration first */
        status = pl022_dma_autoprobe(pl022);
        if (status == -EPROBE_DEFER) {
                dev_dbg(dev, "deferring probe to get DMA channel\n");
                goto err_no_irq;
        }

        /* If that failed, use channels from platform_info */
        if (status == 0)
                platform_info->enable_dma = 1;
        else if (platform_info->enable_dma) {
                status = pl022_dma_probe(pl022);
                if (status != 0)
                        platform_info->enable_dma = 0;
        }

        /* Register with the SPI framework */
        amba_set_drvdata(adev, pl022);
        status = devm_spi_register_master(&adev->dev, master);
        if (status != 0) {
                dev_err(&adev->dev,
                        "probe - problem registering spi master\n");
                goto err_spi_register;
        }
        dev_dbg(dev, "probe succeeded\n");

        /* let runtime pm put suspend */
        if (platform_info->autosuspend_delay > 0) {
                dev_info(&adev->dev,
                        "will use autosuspend for runtime pm, delay %dms\n",
                        platform_info->autosuspend_delay);
                pm_runtime_set_autosuspend_delay(dev,
                        platform_info->autosuspend_delay);
                pm_runtime_use_autosuspend(dev);
        }
        pm_runtime_put(dev);

        return 0;

 err_spi_register:
        if (platform_info->enable_dma)
                pl022_dma_remove(pl022);
 err_no_irq:
        clk_disable_unprepare(pl022->clk);
 err_no_clk_en:
 err_no_clk:
 err_no_ioremap:
        amba_release_regions(adev);
 err_no_ioregion:
 err_no_gpio:
 err_no_mem:
        spi_master_put(master);
        return status;
}

static int
pl022_remove(struct amba_device *adev)
{
        struct pl022 *pl022 = amba_get_drvdata(adev);

        if (!pl022)
                return 0;

        /*
         * undo pm_runtime_put() in probe.  I assume that we're not
         * accessing the primecell here.
         */
        pm_runtime_get_noresume(&adev->dev);

        load_ssp_default_config(pl022);
        if (pl022->master_info->enable_dma)
                pl022_dma_remove(pl022);

        clk_disable_unprepare(pl022->clk);
        amba_release_regions(adev);
        tasklet_disable(&pl022->pump_transfers);
        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int pl022_suspend(struct device *dev)
{
        struct pl022 *pl022 = dev_get_drvdata(dev);
        int ret;

        ret = spi_master_suspend(pl022->master);
        if (ret) {
                dev_warn(dev, "cannot suspend master\n");
                return ret;
        }

        ret = pm_runtime_force_suspend(dev);
        if (ret) {
                spi_master_resume(pl022->master);
                return ret;
        }

        pinctrl_pm_select_sleep_state(dev);

        dev_dbg(dev, "suspended\n");
        return 0;
}

static int pl022_resume(struct device *dev)
{
        struct pl022 *pl022 = dev_get_drvdata(dev);
        int ret;

        ret = pm_runtime_force_resume(dev);
        if (ret)
                dev_err(dev, "problem resuming\n");

        /* Start the queue running */
        ret = spi_master_resume(pl022->master);
        if (ret)
                dev_err(dev, "problem starting queue (%d)\n", ret);
        else
                dev_dbg(dev, "resumed\n");

        return ret;
}
#endif

#ifdef CONFIG_PM
static int pl022_runtime_suspend(struct device *dev)
{
        struct pl022 *pl022 = dev_get_drvdata(dev);

        clk_disable_unprepare(pl022->clk);
        pinctrl_pm_select_idle_state(dev);

        return 0;
}

static int pl022_runtime_resume(struct device *dev)
{
        struct pl022 *pl022 = dev_get_drvdata(dev);

        pinctrl_pm_select_default_state(dev);
        clk_prepare_enable(pl022->clk);

        return 0;
}
#endif

static const struct dev_pm_ops pl022_dev_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(pl022_suspend, pl022_resume)
        SET_RUNTIME_PM_OPS(pl022_runtime_suspend, pl022_runtime_resume, NULL)
};

static struct vendor_data vendor_arm = {
        .fifodepth = 8,
        .max_bpw = 16,
        .unidir = false,
        .extended_cr = false,
        .pl023 = false,
        .loopback = true,
        .internal_cs_ctrl = false,
};

static struct vendor_data vendor_st = {
        .fifodepth = 32,
        .max_bpw = 32,
        .unidir = false,
        .extended_cr = true,
        .pl023 = false,
        .loopback = true,
        .internal_cs_ctrl = false,
};

static struct vendor_data vendor_st_pl023 = {
        .fifodepth = 32,
        .max_bpw = 32,
        .unidir = false,
        .extended_cr = true,
        .pl023 = true,
        .loopback = false,
        .internal_cs_ctrl = false,
};

static struct vendor_data vendor_lsi = {
        .fifodepth = 8,
        .max_bpw = 16,
        .unidir = false,
        .extended_cr = false,
        .pl023 = false,
        .loopback = true,
        .internal_cs_ctrl = true,
};

static const struct amba_id pl022_ids[] = {
        {
                /*
                 * ARM PL022 variant, this has a 16bit wide
                 * and 8 locations deep TX/RX FIFO
                 */
                .id     = 0x00041022,
                .mask   = 0x000fffff,
                .data   = &vendor_arm,
        },
        {
                /*
                 * ST Micro derivative, this has 32bit wide
                 * and 32 locations deep TX/RX FIFO
                 */
                .id     = 0x01080022,
                .mask   = 0xffffffff,
                .data   = &vendor_st,
        },
        {
                /*
                 * ST-Ericsson derivative "PL023" (this is not
                 * an official ARM number), this is a PL022 SSP block
                 * stripped to SPI mode only, it has 32bit wide
                 * and 32 locations deep TX/RX FIFO but no extended
                 * CR0/CR1 register
                 */
                .id     = 0x00080023,
                .mask   = 0xffffffff,
                .data   = &vendor_st_pl023,
        },
        {
                /*
                 * PL022 variant that has a chip select control register whih
                 * allows control of 5 output signals nCS[0:4].
                 */
                .id     = 0x000b6022,
                .mask   = 0x000fffff,
                .data   = &vendor_lsi,
        },
        { 0, 0 },
};

MODULE_DEVICE_TABLE(amba, pl022_ids);

static struct amba_driver pl022_driver = {
        .drv = {
                .name   = "ssp-pl022",
                .pm     = &pl022_dev_pm_ops,
        },
        .id_table       = pl022_ids,
        .probe          = pl022_probe,
        .remove         = pl022_remove,
};

static int __init pl022_init(void)
{
        return amba_driver_register(&pl022_driver);
}
subsys_initcall(pl022_init);

static void __exit pl022_exit(void)
{
        amba_driver_unregister(&pl022_driver);
}
module_exit(pl022_exit);

MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
MODULE_DESCRIPTION("PL022 SSP Controller Driver");
MODULE_LICENSE("GPL");