// SPDX-License-Identifier: GPL-2.0
/*
 * Freescale QUICC Engine UART device driver
 *
 * Author: Timur Tabi <timur@freescale.com>
 *
 * Copyright 2007 Freescale Semiconductor, Inc.
 *
 * This driver adds support for UART devices via Freescale's QUICC Engine
 * found on some Freescale SOCs.
 *
 * If Soft-UART support is needed but not already present, then this driver
 * will request and upload the "Soft-UART" microcode upon probe.  The
 * filename of the microcode should be fsl_qe_ucode_uart_X_YZ.bin, where "X"
 * is the name of the SOC (e.g. 8323), and YZ is the revision of the SOC,
 * (e.g. "11" for 1.1).
 */

#include <linux/module.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/dma-mapping.h>

#include <linux/fs_uart_pd.h>
#include <soc/fsl/qe/ucc_slow.h>

#include <linux/firmware.h>
#include <soc/fsl/cpm.h>

#ifdef CONFIG_PPC32
#include <asm/reg.h> /* mfspr, SPRN_SVR */
#endif

/*
 * The GUMR flag for Soft UART.  This would normally be defined in qe.h,
 * but Soft-UART is a hack and we want to keep everything related to it in
 * this file.
 */
#define UCC_SLOW_GUMR_H_SUART           0x00004000      /* Soft-UART */

/*
 * soft_uart is 1 if we need to use Soft-UART mode
 */
static int soft_uart;
/*
 * firmware_loaded is 1 if the firmware has been loaded, 0 otherwise.
 */
static int firmware_loaded;

/* Enable this macro to configure all serial ports in internal loopback
   mode */
/* #define LOOPBACK */

/* The major and minor device numbers are defined in
 * http://www.lanana.org/docs/device-list/devices-2.6+.txt.  For the QE
 * UART, we have major number 204 and minor numbers 46 - 49, which are the
 * same as for the CPM2.  This decision was made because no Freescale part
 * has both a CPM and a QE.
 */
#define SERIAL_QE_MAJOR 204
#define SERIAL_QE_MINOR 46

/* Since we only have minor numbers 46 - 49, there is a hard limit of 4 ports */
#define UCC_MAX_UART    4

/* The number of buffer descriptors for receiving characters. */
#define RX_NUM_FIFO     4

/* The number of buffer descriptors for transmitting characters. */
#define TX_NUM_FIFO     4

/* The maximum size of the character buffer for a single RX BD. */
#define RX_BUF_SIZE     32

/* The maximum size of the character buffer for a single TX BD. */
#define TX_BUF_SIZE     32

/*
 * The number of jiffies to wait after receiving a close command before the
 * device is actually closed.  This allows the last few characters to be
 * sent over the wire.
 */
#define UCC_WAIT_CLOSING 100

struct ucc_uart_pram {
        struct ucc_slow_pram common;
        u8 res1[8];             /* reserved */
        __be16 maxidl;          /* Maximum idle chars */
        __be16 idlc;            /* temp idle counter */
        __be16 brkcr;           /* Break count register */
        __be16 parec;           /* receive parity error counter */
        __be16 frmec;           /* receive framing error counter */
        __be16 nosec;           /* receive noise counter */
        __be16 brkec;           /* receive break condition counter */
        __be16 brkln;           /* last received break length */
        __be16 uaddr[2];        /* UART address character 1 & 2 */
        __be16 rtemp;           /* Temp storage */
        __be16 toseq;           /* Transmit out of sequence char */
        __be16 cchars[8];       /* control characters 1-8 */
        __be16 rccm;            /* receive control character mask */
        __be16 rccr;            /* receive control character register */
        __be16 rlbc;            /* receive last break character */
        __be16 res2;            /* reserved */
        __be32 res3;            /* reserved, should be cleared */
        u8 res4;                /* reserved, should be cleared */
        u8 res5[3];             /* reserved, should be cleared */
        __be32 res6;            /* reserved, should be cleared */
        __be32 res7;            /* reserved, should be cleared */
        __be32 res8;            /* reserved, should be cleared */
        __be32 res9;            /* reserved, should be cleared */
        __be32 res10;           /* reserved, should be cleared */
        __be32 res11;           /* reserved, should be cleared */
        __be32 res12;           /* reserved, should be cleared */
        __be32 res13;           /* reserved, should be cleared */
/* The rest is for Soft-UART only */
        __be16 supsmr;          /* 0x90, Shadow UPSMR */
        __be16 res92;           /* 0x92, reserved, initialize to 0 */
        __be32 rx_state;        /* 0x94, RX state, initialize to 0 */
        __be32 rx_cnt;          /* 0x98, RX count, initialize to 0 */
        u8 rx_length;           /* 0x9C, Char length, set to 1+CL+PEN+1+SL */
        u8 rx_bitmark;          /* 0x9D, reserved, initialize to 0 */
        u8 rx_temp_dlst_qe;     /* 0x9E, reserved, initialize to 0 */
        u8 res14[0xBC - 0x9F];  /* reserved */
        __be32 dump_ptr;        /* 0xBC, Dump pointer */
        __be32 rx_frame_rem;    /* 0xC0, reserved, initialize to 0 */
        u8 rx_frame_rem_size;   /* 0xC4, reserved, initialize to 0 */
        u8 tx_mode;             /* 0xC5, mode, 0=AHDLC, 1=UART */
        __be16 tx_state;        /* 0xC6, TX state */
        u8 res15[0xD0 - 0xC8];  /* reserved */
        __be32 resD0;           /* 0xD0, reserved, initialize to 0 */
        u8 resD4;               /* 0xD4, reserved, initialize to 0 */
        __be16 resD5;           /* 0xD5, reserved, initialize to 0 */
} __attribute__ ((packed));

/* SUPSMR definitions, for Soft-UART only */
#define UCC_UART_SUPSMR_SL              0x8000
#define UCC_UART_SUPSMR_RPM_MASK        0x6000
#define UCC_UART_SUPSMR_RPM_ODD         0x0000
#define UCC_UART_SUPSMR_RPM_LOW         0x2000
#define UCC_UART_SUPSMR_RPM_EVEN        0x4000
#define UCC_UART_SUPSMR_RPM_HIGH        0x6000
#define UCC_UART_SUPSMR_PEN             0x1000
#define UCC_UART_SUPSMR_TPM_MASK        0x0C00
#define UCC_UART_SUPSMR_TPM_ODD         0x0000
#define UCC_UART_SUPSMR_TPM_LOW         0x0400
#define UCC_UART_SUPSMR_TPM_EVEN        0x0800
#define UCC_UART_SUPSMR_TPM_HIGH        0x0C00
#define UCC_UART_SUPSMR_FRZ             0x0100
#define UCC_UART_SUPSMR_UM_MASK         0x00c0
#define UCC_UART_SUPSMR_UM_NORMAL       0x0000
#define UCC_UART_SUPSMR_UM_MAN_MULTI    0x0040
#define UCC_UART_SUPSMR_UM_AUTO_MULTI   0x00c0
#define UCC_UART_SUPSMR_CL_MASK         0x0030
#define UCC_UART_SUPSMR_CL_8            0x0030
#define UCC_UART_SUPSMR_CL_7            0x0020
#define UCC_UART_SUPSMR_CL_6            0x0010
#define UCC_UART_SUPSMR_CL_5            0x0000

#define UCC_UART_TX_STATE_AHDLC         0x00
#define UCC_UART_TX_STATE_UART          0x01
#define UCC_UART_TX_STATE_X1            0x00
#define UCC_UART_TX_STATE_X16           0x80

#define UCC_UART_PRAM_ALIGNMENT 0x100

#define UCC_UART_SIZE_OF_BD     UCC_SLOW_SIZE_OF_BD
#define NUM_CONTROL_CHARS       8

/* Private per-port data structure */
struct uart_qe_port {
        struct uart_port port;
        struct ucc_slow __iomem *uccp;
        struct ucc_uart_pram __iomem *uccup;
        struct ucc_slow_info us_info;
        struct ucc_slow_private *us_private;
        struct device_node *np;
        unsigned int ucc_num;   /* First ucc is 0, not 1 */

        u16 rx_nrfifos;
        u16 rx_fifosize;
        u16 tx_nrfifos;
        u16 tx_fifosize;
        int wait_closing;
        u32 flags;
        struct qe_bd *rx_bd_base;
        struct qe_bd *rx_cur;
        struct qe_bd *tx_bd_base;
        struct qe_bd *tx_cur;
        unsigned char *tx_buf;
        unsigned char *rx_buf;
        void *bd_virt;          /* virtual address of the BD buffers */
        dma_addr_t bd_dma_addr; /* bus address of the BD buffers */
        unsigned int bd_size;   /* size of BD buffer space */
};

static struct uart_driver ucc_uart_driver = {
        .owner          = THIS_MODULE,
        .driver_name    = "ucc_uart",
        .dev_name       = "ttyQE",
        .major          = SERIAL_QE_MAJOR,
        .minor          = SERIAL_QE_MINOR,
        .nr             = UCC_MAX_UART,
};

/*
 * Virtual to physical address translation.
 *
 * Given the virtual address for a character buffer, this function returns
 * the physical (DMA) equivalent.
 */
static inline dma_addr_t cpu2qe_addr(void *addr, struct uart_qe_port *qe_port)
{
        if (likely((addr >= qe_port->bd_virt)) &&
            (addr < (qe_port->bd_virt + qe_port->bd_size)))
                return qe_port->bd_dma_addr + (addr - qe_port->bd_virt);

        /* something nasty happened */
        printk(KERN_ERR "%s: addr=%p\n", __func__, addr);
        BUG();
        return 0;
}

/*
 * Physical to virtual address translation.
 *
 * Given the physical (DMA) address for a character buffer, this function
 * returns the virtual equivalent.
 */
static inline void *qe2cpu_addr(dma_addr_t addr, struct uart_qe_port *qe_port)
{
        /* sanity check */
        if (likely((addr >= qe_port->bd_dma_addr) &&
                   (addr < (qe_port->bd_dma_addr + qe_port->bd_size))))
                return qe_port->bd_virt + (addr - qe_port->bd_dma_addr);

        /* something nasty happened */
        printk(KERN_ERR "%s: addr=%llx\n", __func__, (u64)addr);
        BUG();
        return NULL;
}

/*
 * Return 1 if the QE is done transmitting all buffers for this port
 *
 * This function scans each BD in sequence.  If we find a BD that is not
 * ready (READY=1), then we return 0 indicating that the QE is still sending
 * data.  If we reach the last BD (WRAP=1), then we know we've scanned
 * the entire list, and all BDs are done.
 */
static unsigned int qe_uart_tx_empty(struct uart_port *port)
{
        struct uart_qe_port *qe_port =
                container_of(port, struct uart_qe_port, port);
        struct qe_bd *bdp = qe_port->tx_bd_base;

        while (1) {
                if (qe_ioread16be(&bdp->status) & BD_SC_READY)
                        /* This BD is not done, so return "not done" */
                        return 0;

                if (qe_ioread16be(&bdp->status) & BD_SC_WRAP)
                        /*
                         * This BD is done and it's the last one, so return
                         * "done"
                         */
                        return 1;

                bdp++;
        }
}

/*
 * Set the modem control lines
 *
 * Although the QE can control the modem control lines (e.g. CTS), we
 * don't need that support. This function must exist, however, otherwise
 * the kernel will panic.
 */
void qe_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
}

/*
 * Get the current modem control line status
 *
 * Although the QE can control the modem control lines (e.g. CTS), this
 * driver currently doesn't support that, so we always return Carrier
 * Detect, Data Set Ready, and Clear To Send.
 */
static unsigned int qe_uart_get_mctrl(struct uart_port *port)
{
        return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
}

/*
 * Disable the transmit interrupt.
 *
 * Although this function is called "stop_tx", it does not actually stop
 * transmission of data.  Instead, it tells the QE to not generate an
 * interrupt when the UCC is finished sending characters.
 */
static void qe_uart_stop_tx(struct uart_port *port)
{
        struct uart_qe_port *qe_port =
                container_of(port, struct uart_qe_port, port);

        qe_clrbits_be16(&qe_port->uccp->uccm, UCC_UART_UCCE_TX);
}

/*
 * Transmit as many characters to the HW as possible.
 *
 * This function will attempt to stuff of all the characters from the
 * kernel's transmit buffer into TX BDs.
 *
 * A return value of non-zero indicates that it successfully stuffed all
 * characters from the kernel buffer.
 *
 * A return value of zero indicates that there are still characters in the
 * kernel's buffer that have not been transmitted, but there are no more BDs
 * available.  This function should be called again after a BD has been made
 * available.
 */
static int qe_uart_tx_pump(struct uart_qe_port *qe_port)
{
        struct qe_bd *bdp;
        unsigned char *p;
        unsigned int count;
        struct uart_port *port = &qe_port->port;
        struct circ_buf *xmit = &port->state->xmit;

        /* Handle xon/xoff */
        if (port->x_char) {
                /* Pick next descriptor and fill from buffer */
                bdp = qe_port->tx_cur;

                p = qe2cpu_addr(be32_to_cpu(bdp->buf), qe_port);

                *p++ = port->x_char;
                qe_iowrite16be(1, &bdp->length);
                qe_setbits_be16(&bdp->status, BD_SC_READY);
                /* Get next BD. */
                if (qe_ioread16be(&bdp->status) & BD_SC_WRAP)
                        bdp = qe_port->tx_bd_base;
                else
                        bdp++;
                qe_port->tx_cur = bdp;

                port->icount.tx++;
                port->x_char = 0;
                return 1;
        }

        if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
                qe_uart_stop_tx(port);
                return 0;
        }

        /* Pick next descriptor and fill from buffer */
        bdp = qe_port->tx_cur;

        while (!(qe_ioread16be(&bdp->status) & BD_SC_READY) &&
               (xmit->tail != xmit->head)) {
                count = 0;
                p = qe2cpu_addr(be32_to_cpu(bdp->buf), qe_port);
                while (count < qe_port->tx_fifosize) {
                        *p++ = xmit->buf[xmit->tail];
                        xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                        port->icount.tx++;
                        count++;
                        if (xmit->head == xmit->tail)
                                break;
                }

                qe_iowrite16be(count, &bdp->length);
                qe_setbits_be16(&bdp->status, BD_SC_READY);

                /* Get next BD. */
                if (qe_ioread16be(&bdp->status) & BD_SC_WRAP)
                        bdp = qe_port->tx_bd_base;
                else
                        bdp++;
        }
        qe_port->tx_cur = bdp;

        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                uart_write_wakeup(port);

        if (uart_circ_empty(xmit)) {
                /* The kernel buffer is empty, so turn off TX interrupts.  We
                   don't need to be told when the QE is finished transmitting
                   the data. */
                qe_uart_stop_tx(port);
                return 0;
        }

        return 1;
}

/*
 * Start transmitting data
 *
 * This function will start transmitting any available data, if the port
 * isn't already transmitting data.
 */
static void qe_uart_start_tx(struct uart_port *port)
{
        struct uart_qe_port *qe_port =
                container_of(port, struct uart_qe_port, port);

        /* If we currently are transmitting, then just return */
        if (qe_ioread16be(&qe_port->uccp->uccm) & UCC_UART_UCCE_TX)
                return;

        /* Otherwise, pump the port and start transmission */
        if (qe_uart_tx_pump(qe_port))
                qe_setbits_be16(&qe_port->uccp->uccm, UCC_UART_UCCE_TX);
}

/*
 * Stop transmitting data
 */
static void qe_uart_stop_rx(struct uart_port *port)
{
        struct uart_qe_port *qe_port =
                container_of(port, struct uart_qe_port, port);

        qe_clrbits_be16(&qe_port->uccp->uccm, UCC_UART_UCCE_RX);
}

/* Start or stop sending  break signal
 *
 * This function controls the sending of a break signal.  If break_state=1,
 * then we start sending a break signal.  If break_state=0, then we stop
 * sending the break signal.
 */
static void qe_uart_break_ctl(struct uart_port *port, int break_state)
{
        struct uart_qe_port *qe_port =
                container_of(port, struct uart_qe_port, port);

        if (break_state)
                ucc_slow_stop_tx(qe_port->us_private);
        else
                ucc_slow_restart_tx(qe_port->us_private);
}

/* ISR helper function for receiving character.
 *
 * This function is called by the ISR to handling receiving characters
 */
static void qe_uart_int_rx(struct uart_qe_port *qe_port)
{
        int i;
        unsigned char ch, *cp;
        struct uart_port *port = &qe_port->port;
        struct tty_port *tport = &port->state->port;
        struct qe_bd *bdp;
        u16 status;
        unsigned int flg;

        /* Just loop through the closed BDs and copy the characters into
         * the buffer.
         */
        bdp = qe_port->rx_cur;
        while (1) {
                status = qe_ioread16be(&bdp->status);

                /* If this one is empty, then we assume we've read them all */
                if (status & BD_SC_EMPTY)
                        break;

                /* get number of characters, and check space in RX buffer */
                i = qe_ioread16be(&bdp->length);

                /* If we don't have enough room in RX buffer for the entire BD,
                 * then we try later, which will be the next RX interrupt.
                 */
                if (tty_buffer_request_room(tport, i) < i) {
                        dev_dbg(port->dev, "ucc-uart: no room in RX buffer\n");
                        return;
                }

                /* get pointer */
                cp = qe2cpu_addr(be32_to_cpu(bdp->buf), qe_port);

                /* loop through the buffer */
                while (i-- > 0) {
                        ch = *cp++;
                        port->icount.rx++;
                        flg = TTY_NORMAL;

                        if (!i && status &
                            (BD_SC_BR | BD_SC_FR | BD_SC_PR | BD_SC_OV))
                                goto handle_error;
                        if (uart_handle_sysrq_char(port, ch))
                                continue;

error_return:
                        tty_insert_flip_char(tport, ch, flg);

                }

                /* This BD is ready to be used again. Clear status. get next */
                qe_clrsetbits_be16(&bdp->status,
                                   BD_SC_BR | BD_SC_FR | BD_SC_PR | BD_SC_OV | BD_SC_ID,
                                   BD_SC_EMPTY);
                if (qe_ioread16be(&bdp->status) & BD_SC_WRAP)
                        bdp = qe_port->rx_bd_base;
                else
                        bdp++;

        }

        /* Write back buffer pointer */
        qe_port->rx_cur = bdp;

        /* Activate BH processing */
        tty_flip_buffer_push(tport);

        return;

        /* Error processing */

handle_error:
        /* Statistics */
        if (status & BD_SC_BR)
                port->icount.brk++;
        if (status & BD_SC_PR)
                port->icount.parity++;
        if (status & BD_SC_FR)
                port->icount.frame++;
        if (status & BD_SC_OV)
                port->icount.overrun++;

        /* Mask out ignored conditions */
        status &= port->read_status_mask;

        /* Handle the remaining ones */
        if (status & BD_SC_BR)
                flg = TTY_BREAK;
        else if (status & BD_SC_PR)
                flg = TTY_PARITY;
        else if (status & BD_SC_FR)
                flg = TTY_FRAME;

        /* Overrun does not affect the current character ! */
        if (status & BD_SC_OV)
                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
        port->sysrq = 0;
        goto error_return;
}

/* Interrupt handler
 *
 * This interrupt handler is called after a BD is processed.
 */
static irqreturn_t qe_uart_int(int irq, void *data)
{
        struct uart_qe_port *qe_port = (struct uart_qe_port *) data;
        struct ucc_slow __iomem *uccp = qe_port->uccp;
        u16 events;

        /* Clear the interrupts */
        events = qe_ioread16be(&uccp->ucce);
        qe_iowrite16be(events, &uccp->ucce);

        if (events & UCC_UART_UCCE_BRKE)
                uart_handle_break(&qe_port->port);

        if (events & UCC_UART_UCCE_RX)
                qe_uart_int_rx(qe_port);

        if (events & UCC_UART_UCCE_TX)
                qe_uart_tx_pump(qe_port);

        return events ? IRQ_HANDLED : IRQ_NONE;
}

/* Initialize buffer descriptors
 *
 * This function initializes all of the RX and TX buffer descriptors.
 */
static void qe_uart_initbd(struct uart_qe_port *qe_port)
{
        int i;
        void *bd_virt;
        struct qe_bd *bdp;

        /* Set the physical address of the host memory buffers in the buffer
         * descriptors, and the virtual address for us to work with.
         */
        bd_virt = qe_port->bd_virt;
        bdp = qe_port->rx_bd_base;
        qe_port->rx_cur = qe_port->rx_bd_base;
        for (i = 0; i < (qe_port->rx_nrfifos - 1); i++) {
                qe_iowrite16be(BD_SC_EMPTY | BD_SC_INTRPT, &bdp->status);
                qe_iowrite32be(cpu2qe_addr(bd_virt, qe_port), &bdp->buf);
                qe_iowrite16be(0, &bdp->length);
                bd_virt += qe_port->rx_fifosize;
                bdp++;
        }

        /* */
        qe_iowrite16be(BD_SC_WRAP | BD_SC_EMPTY | BD_SC_INTRPT, &bdp->status);
        qe_iowrite32be(cpu2qe_addr(bd_virt, qe_port), &bdp->buf);
        qe_iowrite16be(0, &bdp->length);

        /* Set the physical address of the host memory
         * buffers in the buffer descriptors, and the
         * virtual address for us to work with.
         */
        bd_virt = qe_port->bd_virt +
                L1_CACHE_ALIGN(qe_port->rx_nrfifos * qe_port->rx_fifosize);
        qe_port->tx_cur = qe_port->tx_bd_base;
        bdp = qe_port->tx_bd_base;
        for (i = 0; i < (qe_port->tx_nrfifos - 1); i++) {
                qe_iowrite16be(BD_SC_INTRPT, &bdp->status);
                qe_iowrite32be(cpu2qe_addr(bd_virt, qe_port), &bdp->buf);
                qe_iowrite16be(0, &bdp->length);
                bd_virt += qe_port->tx_fifosize;
                bdp++;
        }

        /* Loopback requires the preamble bit to be set on the first TX BD */
#ifdef LOOPBACK
        qe_setbits_be16(&qe_port->tx_cur->status, BD_SC_P);
#endif

        qe_iowrite16be(BD_SC_WRAP | BD_SC_INTRPT, &bdp->status);
        qe_iowrite32be(cpu2qe_addr(bd_virt, qe_port), &bdp->buf);
        qe_iowrite16be(0, &bdp->length);
}

/*
 * Initialize a UCC for UART.
 *
 * This function configures a given UCC to be used as a UART device. Basic
 * UCC initialization is handled in qe_uart_request_port().  This function
 * does all the UART-specific stuff.
 */
static void qe_uart_init_ucc(struct uart_qe_port *qe_port)
{
        u32 cecr_subblock;
        struct ucc_slow __iomem *uccp = qe_port->uccp;
        struct ucc_uart_pram *uccup = qe_port->uccup;

        unsigned int i;

        /* First, disable TX and RX in the UCC */
        ucc_slow_disable(qe_port->us_private, COMM_DIR_RX_AND_TX);

        /* Program the UCC UART parameter RAM */
        qe_iowrite8(UCC_BMR_GBL | UCC_BMR_BO_BE, &uccup->common.rbmr);
        qe_iowrite8(UCC_BMR_GBL | UCC_BMR_BO_BE, &uccup->common.tbmr);
        qe_iowrite16be(qe_port->rx_fifosize, &uccup->common.mrblr);
        qe_iowrite16be(0x10, &uccup->maxidl);
        qe_iowrite16be(1, &uccup->brkcr);
        qe_iowrite16be(0, &uccup->parec);
        qe_iowrite16be(0, &uccup->frmec);
        qe_iowrite16be(0, &uccup->nosec);
        qe_iowrite16be(0, &uccup->brkec);
        qe_iowrite16be(0, &uccup->uaddr[0]);
        qe_iowrite16be(0, &uccup->uaddr[1]);
        qe_iowrite16be(0, &uccup->toseq);
        for (i = 0; i < 8; i++)
                qe_iowrite16be(0xC000, &uccup->cchars[i]);
        qe_iowrite16be(0xc0ff, &uccup->rccm);

        /* Configure the GUMR registers for UART */
        if (soft_uart) {
                /* Soft-UART requires a 1X multiplier for TX */
                qe_clrsetbits_be32(&uccp->gumr_l,
                                   UCC_SLOW_GUMR_L_MODE_MASK | UCC_SLOW_GUMR_L_TDCR_MASK | UCC_SLOW_GUMR_L_RDCR_MASK,
                                   UCC_SLOW_GUMR_L_MODE_UART | UCC_SLOW_GUMR_L_TDCR_1 | UCC_SLOW_GUMR_L_RDCR_16);

                qe_clrsetbits_be32(&uccp->gumr_h, UCC_SLOW_GUMR_H_RFW,
                                   UCC_SLOW_GUMR_H_TRX | UCC_SLOW_GUMR_H_TTX);
        } else {
                qe_clrsetbits_be32(&uccp->gumr_l,
                                   UCC_SLOW_GUMR_L_MODE_MASK | UCC_SLOW_GUMR_L_TDCR_MASK | UCC_SLOW_GUMR_L_RDCR_MASK,
                                   UCC_SLOW_GUMR_L_MODE_UART | UCC_SLOW_GUMR_L_TDCR_16 | UCC_SLOW_GUMR_L_RDCR_16);

                qe_clrsetbits_be32(&uccp->gumr_h,
                                   UCC_SLOW_GUMR_H_TRX | UCC_SLOW_GUMR_H_TTX,
                                   UCC_SLOW_GUMR_H_RFW);
        }

#ifdef LOOPBACK
        qe_clrsetbits_be32(&uccp->gumr_l, UCC_SLOW_GUMR_L_DIAG_MASK,
                           UCC_SLOW_GUMR_L_DIAG_LOOP);
        qe_clrsetbits_be32(&uccp->gumr_h,
                           UCC_SLOW_GUMR_H_CTSP | UCC_SLOW_GUMR_H_RSYN,
                           UCC_SLOW_GUMR_H_CDS);
#endif

        /* Disable rx interrupts  and clear all pending events.  */
        qe_iowrite16be(0, &uccp->uccm);
        qe_iowrite16be(0xffff, &uccp->ucce);
        qe_iowrite16be(0x7e7e, &uccp->udsr);

        /* Initialize UPSMR */
        qe_iowrite16be(0, &uccp->upsmr);

        if (soft_uart) {
                qe_iowrite16be(0x30, &uccup->supsmr);
                qe_iowrite16be(0, &uccup->res92);
                qe_iowrite32be(0, &uccup->rx_state);
                qe_iowrite32be(0, &uccup->rx_cnt);
                qe_iowrite8(0, &uccup->rx_bitmark);
                qe_iowrite8(10, &uccup->rx_length);
                qe_iowrite32be(0x4000, &uccup->dump_ptr);
                qe_iowrite8(0, &uccup->rx_temp_dlst_qe);
                qe_iowrite32be(0, &uccup->rx_frame_rem);
                qe_iowrite8(0, &uccup->rx_frame_rem_size);
                /* Soft-UART requires TX to be 1X */
                qe_iowrite8(UCC_UART_TX_STATE_UART | UCC_UART_TX_STATE_X1,
                            &uccup->tx_mode);
                qe_iowrite16be(0, &uccup->tx_state);
                qe_iowrite8(0, &uccup->resD4);
                qe_iowrite16be(0, &uccup->resD5);

                /* Set UART mode.
                 * Enable receive and transmit.
                 */

                /* From the microcode errata:
                 * 1.GUMR_L register, set mode=0010 (QMC).
                 * 2.Set GUMR_H[17] bit. (UART/AHDLC mode).
                 * 3.Set GUMR_H[19:20] (Transparent mode)
                 * 4.Clear GUMR_H[26] (RFW)
                 * ...
                 * 6.Receiver must use 16x over sampling
                 */
                qe_clrsetbits_be32(&uccp->gumr_l,
                                   UCC_SLOW_GUMR_L_MODE_MASK | UCC_SLOW_GUMR_L_TDCR_MASK | UCC_SLOW_GUMR_L_RDCR_MASK,
                                   UCC_SLOW_GUMR_L_MODE_QMC | UCC_SLOW_GUMR_L_TDCR_16 | UCC_SLOW_GUMR_L_RDCR_16);

                qe_clrsetbits_be32(&uccp->gumr_h,
                                   UCC_SLOW_GUMR_H_RFW | UCC_SLOW_GUMR_H_RSYN,
                                   UCC_SLOW_GUMR_H_SUART | UCC_SLOW_GUMR_H_TRX | UCC_SLOW_GUMR_H_TTX | UCC_SLOW_GUMR_H_TFL);

#ifdef LOOPBACK
                qe_clrsetbits_be32(&uccp->gumr_l, UCC_SLOW_GUMR_L_DIAG_MASK,
                                   UCC_SLOW_GUMR_L_DIAG_LOOP);
                qe_clrbits_be32(&uccp->gumr_h,
                                UCC_SLOW_GUMR_H_CTSP | UCC_SLOW_GUMR_H_CDS);
#endif

                cecr_subblock = ucc_slow_get_qe_cr_subblock(qe_port->ucc_num);
                qe_issue_cmd(QE_INIT_TX_RX, cecr_subblock,
                        QE_CR_PROTOCOL_UNSPECIFIED, 0);
        } else {
                cecr_subblock = ucc_slow_get_qe_cr_subblock(qe_port->ucc_num);
                qe_issue_cmd(QE_INIT_TX_RX, cecr_subblock,
                        QE_CR_PROTOCOL_UART, 0);
        }
}

/*
 * Initialize the port.
 */
static int qe_uart_startup(struct uart_port *port)
{
        struct uart_qe_port *qe_port =
                container_of(port, struct uart_qe_port, port);
        int ret;

        /*
         * If we're using Soft-UART mode, then we need to make sure the
         * firmware has been uploaded first.
         */
        if (soft_uart && !firmware_loaded) {
                dev_err(port->dev, "Soft-UART firmware not uploaded\n");
                return -ENODEV;
        }

        qe_uart_initbd(qe_port);
        qe_uart_init_ucc(qe_port);

        /* Install interrupt handler. */
        ret = request_irq(port->irq, qe_uart_int, IRQF_SHARED, "ucc-uart",
                qe_port);
        if (ret) {
                dev_err(port->dev, "could not claim IRQ %u\n", port->irq);
                return ret;
        }

        /* Startup rx-int */
        qe_setbits_be16(&qe_port->uccp->uccm, UCC_UART_UCCE_RX);
        ucc_slow_enable(qe_port->us_private, COMM_DIR_RX_AND_TX);

        return 0;
}

/*
 * Shutdown the port.
 */
static void qe_uart_shutdown(struct uart_port *port)
{
        struct uart_qe_port *qe_port =
                container_of(port, struct uart_qe_port, port);
        struct ucc_slow __iomem *uccp = qe_port->uccp;
        unsigned int timeout = 20;

        /* Disable RX and TX */

        /* Wait for all the BDs marked sent */
        while (!qe_uart_tx_empty(port)) {
                if (!--timeout) {
                        dev_warn(port->dev, "shutdown timeout\n");
                        break;
                }
                set_current_state(TASK_UNINTERRUPTIBLE);
                schedule_timeout(2);
        }

        if (qe_port->wait_closing) {
                /* Wait a bit longer */
                set_current_state(TASK_UNINTERRUPTIBLE);
                schedule_timeout(qe_port->wait_closing);
        }

        /* Stop uarts */
        ucc_slow_disable(qe_port->us_private, COMM_DIR_RX_AND_TX);
        qe_clrbits_be16(&uccp->uccm, UCC_UART_UCCE_TX | UCC_UART_UCCE_RX);

        /* Shut them really down and reinit buffer descriptors */
        ucc_slow_graceful_stop_tx(qe_port->us_private);
        qe_uart_initbd(qe_port);

        free_irq(port->irq, qe_port);
}

/*
 * Set the serial port parameters.
 */
static void qe_uart_set_termios(struct uart_port *port,
                                struct ktermios *termios, struct ktermios *old)
{
        struct uart_qe_port *qe_port =
                container_of(port, struct uart_qe_port, port);
        struct ucc_slow __iomem *uccp = qe_port->uccp;
        unsigned int baud;
        unsigned long flags;
        u16 upsmr = qe_ioread16be(&uccp->upsmr);
        struct ucc_uart_pram __iomem *uccup = qe_port->uccup;
        u16 supsmr = qe_ioread16be(&uccup->supsmr);
        u8 char_length = 2; /* 1 + CL + PEN + 1 + SL */

        /* Character length programmed into the mode register is the
         * sum of: 1 start bit, number of data bits, 0 or 1 parity bit,
         * 1 or 2 stop bits, minus 1.
         * The value 'bits' counts this for us.
         */

        /* byte size */
        upsmr &= UCC_UART_UPSMR_CL_MASK;
        supsmr &= UCC_UART_SUPSMR_CL_MASK;

        switch (termios->c_cflag & CSIZE) {
        case CS5:
                upsmr |= UCC_UART_UPSMR_CL_5;
                supsmr |= UCC_UART_SUPSMR_CL_5;
                char_length += 5;
                break;
        case CS6:
                upsmr |= UCC_UART_UPSMR_CL_6;
                supsmr |= UCC_UART_SUPSMR_CL_6;
                char_length += 6;
                break;
        case CS7:
                upsmr |= UCC_UART_UPSMR_CL_7;
                supsmr |= UCC_UART_SUPSMR_CL_7;
                char_length += 7;
                break;
        default:        /* case CS8 */
                upsmr |= UCC_UART_UPSMR_CL_8;
                supsmr |= UCC_UART_SUPSMR_CL_8;
                char_length += 8;
                break;
        }

        /* If CSTOPB is set, we want two stop bits */
        if (termios->c_cflag & CSTOPB) {
                upsmr |= UCC_UART_UPSMR_SL;
                supsmr |= UCC_UART_SUPSMR_SL;
                char_length++;  /* + SL */
        }

        if (termios->c_cflag & PARENB) {
                upsmr |= UCC_UART_UPSMR_PEN;
                supsmr |= UCC_UART_SUPSMR_PEN;
                char_length++;  /* + PEN */

                if (!(termios->c_cflag & PARODD)) {
                        upsmr &= ~(UCC_UART_UPSMR_RPM_MASK |
                                   UCC_UART_UPSMR_TPM_MASK);
                        upsmr |= UCC_UART_UPSMR_RPM_EVEN |
                                UCC_UART_UPSMR_TPM_EVEN;
                        supsmr &= ~(UCC_UART_SUPSMR_RPM_MASK |
                                    UCC_UART_SUPSMR_TPM_MASK);
                        supsmr |= UCC_UART_SUPSMR_RPM_EVEN |
                                UCC_UART_SUPSMR_TPM_EVEN;
                }
        }

        /*
         * Set up parity check flag
         */
        port->read_status_mask = BD_SC_EMPTY | BD_SC_OV;
        if (termios->c_iflag & INPCK)
                port->read_status_mask |= BD_SC_FR | BD_SC_PR;
        if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
                port->read_status_mask |= BD_SC_BR;

        /*
         * Characters to ignore
         */
        port->ignore_status_mask = 0;
        if (termios->c_iflag & IGNPAR)
                port->ignore_status_mask |= BD_SC_PR | BD_SC_FR;
        if (termios->c_iflag & IGNBRK) {
                port->ignore_status_mask |= BD_SC_BR;
                /*
                 * If we're ignore parity and break indicators, ignore
                 * overruns too.  (For real raw support).
                 */
                if (termios->c_iflag & IGNPAR)
                        port->ignore_status_mask |= BD_SC_OV;
        }
        /*
         * !!! ignore all characters if CREAD is not set
         */
        if ((termios->c_cflag & CREAD) == 0)
                port->read_status_mask &= ~BD_SC_EMPTY;

        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);

        /* Do we really need a spinlock here? */
        spin_lock_irqsave(&port->lock, flags);

        /* Update the per-port timeout. */
        uart_update_timeout(port, termios->c_cflag, baud);

        qe_iowrite16be(upsmr, &uccp->upsmr);
        if (soft_uart) {
                qe_iowrite16be(supsmr, &uccup->supsmr);
                qe_iowrite8(char_length, &uccup->rx_length);

                /* Soft-UART requires a 1X multiplier for TX */
                qe_setbrg(qe_port->us_info.rx_clock, baud, 16);
                qe_setbrg(qe_port->us_info.tx_clock, baud, 1);
        } else {
                qe_setbrg(qe_port->us_info.rx_clock, baud, 16);
                qe_setbrg(qe_port->us_info.tx_clock, baud, 16);
        }

        spin_unlock_irqrestore(&port->lock, flags);
}

/*
 * Return a pointer to a string that describes what kind of port this is.
 */
static const char *qe_uart_type(struct uart_port *port)
{
        return "QE";
}

/*
 * Allocate any memory and I/O resources required by the port.
 */
static int qe_uart_request_port(struct uart_port *port)
{
        int ret;
        struct uart_qe_port *qe_port =
                container_of(port, struct uart_qe_port, port);
        struct ucc_slow_info *us_info = &qe_port->us_info;
        struct ucc_slow_private *uccs;
        unsigned int rx_size, tx_size;
        void *bd_virt;
        dma_addr_t bd_dma_addr = 0;

        ret = ucc_slow_init(us_info, &uccs);
        if (ret) {
                dev_err(port->dev, "could not initialize UCC%u\n",
                       qe_port->ucc_num);
                return ret;
        }

        qe_port->us_private = uccs;
        qe_port->uccp = uccs->us_regs;
        qe_port->uccup = (struct ucc_uart_pram *) uccs->us_pram;

        qe_port->rx_bd_base = uccs->rx_bd;
        qe_port->tx_bd_base = uccs->tx_bd;

        /*
         * Allocate the transmit and receive data buffers.
         */

        rx_size = L1_CACHE_ALIGN(qe_port->rx_nrfifos * qe_port->rx_fifosize);
        tx_size = L1_CACHE_ALIGN(qe_port->tx_nrfifos * qe_port->tx_fifosize);

        bd_virt = dma_alloc_coherent(port->dev, rx_size + tx_size, &bd_dma_addr,
                GFP_KERNEL);
        if (!bd_virt) {
                dev_err(port->dev, "could not allocate buffer descriptors\n");
                return -ENOMEM;
        }

        qe_port->bd_virt = bd_virt;
        qe_port->bd_dma_addr = bd_dma_addr;
        qe_port->bd_size = rx_size + tx_size;

        qe_port->rx_buf = bd_virt;
        qe_port->tx_buf = qe_port->rx_buf + rx_size;

        return 0;
}

/*
 * Configure the port.
 *
 * We say we're a CPM-type port because that's mostly true.  Once the device
 * is configured, this driver operates almost identically to the CPM serial
 * driver.
 */
static void qe_uart_config_port(struct uart_port *port, int flags)
{
        if (flags & UART_CONFIG_TYPE) {
                port->type = PORT_CPM;
                qe_uart_request_port(port);
        }
}

/*
 * Release any memory and I/O resources that were allocated in
 * qe_uart_request_port().
 */
static void qe_uart_release_port(struct uart_port *port)
{
        struct uart_qe_port *qe_port =
                container_of(port, struct uart_qe_port, port);
        struct ucc_slow_private *uccs = qe_port->us_private;

        dma_free_coherent(port->dev, qe_port->bd_size, qe_port->bd_virt,
                          qe_port->bd_dma_addr);

        ucc_slow_free(uccs);
}

/*
 * Verify that the data in serial_struct is suitable for this device.
 */
static int qe_uart_verify_port(struct uart_port *port,
                               struct serial_struct *ser)
{
        if (ser->type != PORT_UNKNOWN && ser->type != PORT_CPM)
                return -EINVAL;

        if (ser->irq < 0 || ser->irq >= nr_irqs)
                return -EINVAL;

        if (ser->baud_base < 9600)
                return -EINVAL;

        return 0;
}
/* UART operations
 *
 * Details on these functions can be found in Documentation/driver-api/serial/driver.rst
 */
static const struct uart_ops qe_uart_pops = {
        .tx_empty       = qe_uart_tx_empty,
        .set_mctrl      = qe_uart_set_mctrl,
        .get_mctrl      = qe_uart_get_mctrl,
        .stop_tx        = qe_uart_stop_tx,
        .start_tx       = qe_uart_start_tx,
        .stop_rx        = qe_uart_stop_rx,
        .break_ctl      = qe_uart_break_ctl,
        .startup        = qe_uart_startup,
        .shutdown       = qe_uart_shutdown,
        .set_termios    = qe_uart_set_termios,
        .type           = qe_uart_type,
        .release_port   = qe_uart_release_port,
        .request_port   = qe_uart_request_port,
        .config_port    = qe_uart_config_port,
        .verify_port    = qe_uart_verify_port,
};


#ifdef CONFIG_PPC32
/*
 * Obtain the SOC model number and revision level
 *
 * This function parses the device tree to obtain the SOC model.  It then
 * reads the SVR register to the revision.
 *
 * The device tree stores the SOC model two different ways.
 *
 * The new way is:
 *
 *              cpu@0 {
 *                      compatible = "PowerPC,8323";
 *                      device_type = "cpu";
 *                      ...
 *
 *
 * The old way is:
 *               PowerPC,8323@0 {
 *                      device_type = "cpu";
 *                      ...
 *
 * This code first checks the new way, and then the old way.
 */
static unsigned int soc_info(unsigned int *rev_h, unsigned int *rev_l)
{
        struct device_node *np;
        const char *soc_string;
        unsigned int svr;
        unsigned int soc;

        /* Find the CPU node */
        np = of_find_node_by_type(NULL, "cpu");
        if (!np)
                return 0;
        /* Find the compatible property */
        soc_string = of_get_property(np, "compatible", NULL);
        if (!soc_string)
                /* No compatible property, so try the name. */
                soc_string = np->name;

        /* Extract the SOC number from the "PowerPC," string */
        if ((sscanf(soc_string, "PowerPC,%u", &soc) != 1) || !soc)
                return 0;

        /* Get the revision from the SVR */
        svr = mfspr(SPRN_SVR);
        *rev_h = (svr >> 4) & 0xf;
        *rev_l = svr & 0xf;

        return soc;
}

/*
 * requst_firmware_nowait() callback function
 *
 * This function is called by the kernel when a firmware is made available,
 * or if it times out waiting for the firmware.
 */
static void uart_firmware_cont(const struct firmware *fw, void *context)
{
        struct qe_firmware *firmware;
        struct device *dev = context;
        int ret;

        if (!fw) {
                dev_err(dev, "firmware not found\n");
                return;
        }

        firmware = (struct qe_firmware *) fw->data;

        if (firmware->header.length != fw->size) {
                dev_err(dev, "invalid firmware\n");
                goto out;
        }

        ret = qe_upload_firmware(firmware);
        if (ret) {
                dev_err(dev, "could not load firmware\n");
                goto out;
        }

        firmware_loaded = 1;
 out:
        release_firmware(fw);
}

static int soft_uart_init(struct platform_device *ofdev)
{
        struct device_node *np = ofdev->dev.of_node;
        struct qe_firmware_info *qe_fw_info;
        int ret;

        if (of_find_property(np, "soft-uart", NULL)) {
                dev_dbg(&ofdev->dev, "using Soft-UART mode\n");
                soft_uart = 1;
        } else {
                return 0;
        }

        qe_fw_info = qe_get_firmware_info();

        /* Check if the firmware has been uploaded. */
        if (qe_fw_info && strstr(qe_fw_info->id, "Soft-UART")) {
                firmware_loaded = 1;
        } else {
                char filename[32];
                unsigned int soc;
                unsigned int rev_h;
                unsigned int rev_l;

                soc = soc_info(&rev_h, &rev_l);
                if (!soc) {
                        dev_err(&ofdev->dev, "unknown CPU model\n");
                        return -ENXIO;
                }
                sprintf(filename, "fsl_qe_ucode_uart_%u_%u%u.bin",
                        soc, rev_h, rev_l);

                dev_info(&ofdev->dev, "waiting for firmware %s\n",
                         filename);

                /*
                 * We call request_firmware_nowait instead of
                 * request_firmware so that the driver can load and
                 * initialize the ports without holding up the rest of
                 * the kernel.  If hotplug support is enabled in the
                 * kernel, then we use it.
                 */
                ret = request_firmware_nowait(THIS_MODULE,
                                              FW_ACTION_HOTPLUG, filename, &ofdev->dev,
                                              GFP_KERNEL, &ofdev->dev, uart_firmware_cont);
                if (ret) {
                        dev_err(&ofdev->dev,
                                "could not load firmware %s\n",
                                filename);
                        return ret;
                }
        }
        return 0;
}

#else /* !CONFIG_PPC32 */

static int soft_uart_init(struct platform_device *ofdev)
{
        return 0;
}

#endif


static int ucc_uart_probe(struct platform_device *ofdev)
{
        struct device_node *np = ofdev->dev.of_node;
        const char *sprop;      /* String OF properties */
        struct uart_qe_port *qe_port = NULL;
        struct resource res;
        u32 val;
        int ret;

        /*
         * Determine if we need Soft-UART mode
         */
        ret = soft_uart_init(ofdev);
        if (ret)
                return ret;

        qe_port = kzalloc(sizeof(struct uart_qe_port), GFP_KERNEL);
        if (!qe_port) {
                dev_err(&ofdev->dev, "can't allocate QE port structure\n");
                return -ENOMEM;
        }

        /* Search for IRQ and mapbase */
        ret = of_address_to_resource(np, 0, &res);
        if (ret) {
                dev_err(&ofdev->dev, "missing 'reg' property in device tree\n");
                goto out_free;
        }
        if (!res.start) {
                dev_err(&ofdev->dev, "invalid 'reg' property in device tree\n");
                ret = -EINVAL;
                goto out_free;
        }
        qe_port->port.mapbase = res.start;

        /* Get the UCC number (device ID) */
        /* UCCs are numbered 1-7 */
        if (of_property_read_u32(np, "cell-index", &val)) {
                if (of_property_read_u32(np, "device-id", &val)) {
                        dev_err(&ofdev->dev, "UCC is unspecified in device tree\n");
                        ret = -EINVAL;
                        goto out_free;
                }
        }

        if (val < 1 || val > UCC_MAX_NUM) {
                dev_err(&ofdev->dev, "no support for UCC%u\n", val);
                ret = -ENODEV;
                goto out_free;
        }
        qe_port->ucc_num = val - 1;

        /*
         * In the future, we should not require the BRG to be specified in the
         * device tree.  If no clock-source is specified, then just pick a BRG
         * to use.  This requires a new QE library function that manages BRG
         * assignments.
         */

        sprop = of_get_property(np, "rx-clock-name", NULL);
        if (!sprop) {
                dev_err(&ofdev->dev, "missing rx-clock-name in device tree\n");
                ret = -ENODEV;
                goto out_free;
        }

        qe_port->us_info.rx_clock = qe_clock_source(sprop);
        if ((qe_port->us_info.rx_clock < QE_BRG1) ||
            (qe_port->us_info.rx_clock > QE_BRG16)) {
                dev_err(&ofdev->dev, "rx-clock-name must be a BRG for UART\n");
                ret = -ENODEV;
                goto out_free;
        }

#ifdef LOOPBACK
        /* In internal loopback mode, TX and RX must use the same clock */
        qe_port->us_info.tx_clock = qe_port->us_info.rx_clock;
#else
        sprop = of_get_property(np, "tx-clock-name", NULL);
        if (!sprop) {
                dev_err(&ofdev->dev, "missing tx-clock-name in device tree\n");
                ret = -ENODEV;
                goto out_free;
        }
        qe_port->us_info.tx_clock = qe_clock_source(sprop);
#endif
        if ((qe_port->us_info.tx_clock < QE_BRG1) ||
            (qe_port->us_info.tx_clock > QE_BRG16)) {
                dev_err(&ofdev->dev, "tx-clock-name must be a BRG for UART\n");
                ret = -ENODEV;
                goto out_free;
        }

        /* Get the port number, numbered 0-3 */
        if (of_property_read_u32(np, "port-number", &val)) {
                dev_err(&ofdev->dev, "missing port-number in device tree\n");
                ret = -EINVAL;
                goto out_free;
        }
        qe_port->port.line = val;
        if (qe_port->port.line >= UCC_MAX_UART) {
                dev_err(&ofdev->dev, "port-number must be 0-%u\n",
                        UCC_MAX_UART - 1);
                ret = -EINVAL;
                goto out_free;
        }

        qe_port->port.irq = irq_of_parse_and_map(np, 0);
        if (qe_port->port.irq == 0) {
                dev_err(&ofdev->dev, "could not map IRQ for UCC%u\n",
                       qe_port->ucc_num + 1);
                ret = -EINVAL;
                goto out_free;
        }

        /*
         * Newer device trees have an "fsl,qe" compatible property for the QE
         * node, but we still need to support older device trees.
         */
        np = of_find_compatible_node(NULL, NULL, "fsl,qe");
        if (!np) {
                np = of_find_node_by_type(NULL, "qe");
                if (!np) {
                        dev_err(&ofdev->dev, "could not find 'qe' node\n");
                        ret = -EINVAL;
                        goto out_free;
                }
        }

        if (of_property_read_u32(np, "brg-frequency", &val)) {
                dev_err(&ofdev->dev,
                       "missing brg-frequency in device tree\n");
                ret = -EINVAL;
                goto out_np;
        }

        if (val)
                qe_port->port.uartclk = val;
        else {
                if (!IS_ENABLED(CONFIG_PPC32)) {
                        dev_err(&ofdev->dev,
                                "invalid brg-frequency in device tree\n");
                        ret = -EINVAL;
                        goto out_np;
                }

                /*
                 * Older versions of U-Boot do not initialize the brg-frequency
                 * property, so in this case we assume the BRG frequency is
                 * half the QE bus frequency.
                 */
                if (of_property_read_u32(np, "bus-frequency", &val)) {
                        dev_err(&ofdev->dev,
                                "missing QE bus-frequency in device tree\n");
                        ret = -EINVAL;
                        goto out_np;
                }
                if (val)
                        qe_port->port.uartclk = val / 2;
                else {
                        dev_err(&ofdev->dev,
                                "invalid QE bus-frequency in device tree\n");
                        ret = -EINVAL;
                        goto out_np;
                }
        }

        spin_lock_init(&qe_port->port.lock);
        qe_port->np = np;
        qe_port->port.dev = &ofdev->dev;
        qe_port->port.ops = &qe_uart_pops;
        qe_port->port.iotype = UPIO_MEM;

        qe_port->tx_nrfifos = TX_NUM_FIFO;
        qe_port->tx_fifosize = TX_BUF_SIZE;
        qe_port->rx_nrfifos = RX_NUM_FIFO;
        qe_port->rx_fifosize = RX_BUF_SIZE;

        qe_port->wait_closing = UCC_WAIT_CLOSING;
        qe_port->port.fifosize = 512;
        qe_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;

        qe_port->us_info.ucc_num = qe_port->ucc_num;
        qe_port->us_info.regs = (phys_addr_t) res.start;
        qe_port->us_info.irq = qe_port->port.irq;

        qe_port->us_info.rx_bd_ring_len = qe_port->rx_nrfifos;
        qe_port->us_info.tx_bd_ring_len = qe_port->tx_nrfifos;

        /* Make sure ucc_slow_init() initializes both TX and RX */
        qe_port->us_info.init_tx = 1;
        qe_port->us_info.init_rx = 1;

        /* Add the port to the uart sub-system.  This will cause
         * qe_uart_config_port() to be called, so the us_info structure must
         * be initialized.
         */
        ret = uart_add_one_port(&ucc_uart_driver, &qe_port->port);
        if (ret) {
                dev_err(&ofdev->dev, "could not add /dev/ttyQE%u\n",
                       qe_port->port.line);
                goto out_np;
        }

        platform_set_drvdata(ofdev, qe_port);

        dev_info(&ofdev->dev, "UCC%u assigned to /dev/ttyQE%u\n",
                qe_port->ucc_num + 1, qe_port->port.line);

        /* Display the mknod command for this device */
        dev_dbg(&ofdev->dev, "mknod command is 'mknod /dev/ttyQE%u c %u %u'\n",
               qe_port->port.line, SERIAL_QE_MAJOR,
               SERIAL_QE_MINOR + qe_port->port.line);

        return 0;
out_np:
        of_node_put(np);
out_free:
        kfree(qe_port);
        return ret;
}

static int ucc_uart_remove(struct platform_device *ofdev)
{
        struct uart_qe_port *qe_port = platform_get_drvdata(ofdev);

        dev_info(&ofdev->dev, "removing /dev/ttyQE%u\n", qe_port->port.line);

        uart_remove_one_port(&ucc_uart_driver, &qe_port->port);

        kfree(qe_port);

        return 0;
}

static const struct of_device_id ucc_uart_match[] = {
        {
                .type = "serial",
                .compatible = "ucc_uart",
        },
        {
                .compatible = "fsl,t1040-ucc-uart",
        },
        {},
};
MODULE_DEVICE_TABLE(of, ucc_uart_match);

static struct platform_driver ucc_uart_of_driver = {
        .driver = {
                .name = "ucc_uart",
                .of_match_table    = ucc_uart_match,
        },
        .probe          = ucc_uart_probe,
        .remove         = ucc_uart_remove,
};

static int __init ucc_uart_init(void)
{
        int ret;

        printk(KERN_INFO "Freescale QUICC Engine UART device driver\n");
#ifdef LOOPBACK
        printk(KERN_INFO "ucc-uart: Using loopback mode\n");
#endif

        ret = uart_register_driver(&ucc_uart_driver);
        if (ret) {
                printk(KERN_ERR "ucc-uart: could not register UART driver\n");
                return ret;
        }

        ret = platform_driver_register(&ucc_uart_of_driver);
        if (ret) {
                printk(KERN_ERR
                       "ucc-uart: could not register platform driver\n");
                uart_unregister_driver(&ucc_uart_driver);
        }

        return ret;
}

static void __exit ucc_uart_exit(void)
{
        printk(KERN_INFO
               "Freescale QUICC Engine UART device driver unloading\n");

        platform_driver_unregister(&ucc_uart_of_driver);
        uart_unregister_driver(&ucc_uart_driver);
}

module_init(ucc_uart_init);
module_exit(ucc_uart_exit);

MODULE_DESCRIPTION("Freescale QUICC Engine (QE) UART");
MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_QE_MAJOR);