// SPDX-License-Identifier: GPL-2.0
/*
 * Support for V3 Semiconductor PCI Local Bus to PCI Bridge
 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
 *
 * Based on the code from arch/arm/mach-integrator/pci_v3.c
 * Copyright (C) 1999 ARM Limited
 * Copyright (C) 2000-2001 Deep Blue Solutions Ltd
 *
 * Contributors to the old driver include:
 * Russell King <linux@armlinux.org.uk>
 * David A. Rusling <david.rusling@linaro.org> (uHAL, ARM Firmware suite)
 * Rob Herring <robh@kernel.org>
 * Liviu Dudau <Liviu.Dudau@arm.com>
 * Grant Likely <grant.likely@secretlab.ca>
 * Arnd Bergmann <arnd@arndb.de>
 * Bjorn Helgaas <bhelgaas@google.com>
 */
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/irq.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/clk.h>

#define V3_PCI_VENDOR                   0x00000000
#define V3_PCI_DEVICE                   0x00000002
#define V3_PCI_CMD                      0x00000004
#define V3_PCI_STAT                     0x00000006
#define V3_PCI_CC_REV                   0x00000008
#define V3_PCI_HDR_CFG                  0x0000000C
#define V3_PCI_IO_BASE                  0x00000010
#define V3_PCI_BASE0                    0x00000014
#define V3_PCI_BASE1                    0x00000018
#define V3_PCI_SUB_VENDOR               0x0000002C
#define V3_PCI_SUB_ID                   0x0000002E
#define V3_PCI_ROM                      0x00000030
#define V3_PCI_BPARAM                   0x0000003C
#define V3_PCI_MAP0                     0x00000040
#define V3_PCI_MAP1                     0x00000044
#define V3_PCI_INT_STAT                 0x00000048
#define V3_PCI_INT_CFG                  0x0000004C
#define V3_LB_BASE0                     0x00000054
#define V3_LB_BASE1                     0x00000058
#define V3_LB_MAP0                      0x0000005E
#define V3_LB_MAP1                      0x00000062
#define V3_LB_BASE2                     0x00000064
#define V3_LB_MAP2                      0x00000066
#define V3_LB_SIZE                      0x00000068
#define V3_LB_IO_BASE                   0x0000006E
#define V3_FIFO_CFG                     0x00000070
#define V3_FIFO_PRIORITY                0x00000072
#define V3_FIFO_STAT                    0x00000074
#define V3_LB_ISTAT                     0x00000076
#define V3_LB_IMASK                     0x00000077
#define V3_SYSTEM                       0x00000078
#define V3_LB_CFG                       0x0000007A
#define V3_PCI_CFG                      0x0000007C
#define V3_DMA_PCI_ADR0                 0x00000080
#define V3_DMA_PCI_ADR1                 0x00000090
#define V3_DMA_LOCAL_ADR0               0x00000084
#define V3_DMA_LOCAL_ADR1               0x00000094
#define V3_DMA_LENGTH0                  0x00000088
#define V3_DMA_LENGTH1                  0x00000098
#define V3_DMA_CSR0                     0x0000008B
#define V3_DMA_CSR1                     0x0000009B
#define V3_DMA_CTLB_ADR0                0x0000008C
#define V3_DMA_CTLB_ADR1                0x0000009C
#define V3_DMA_DELAY                    0x000000E0
#define V3_MAIL_DATA                    0x000000C0
#define V3_PCI_MAIL_IEWR                0x000000D0
#define V3_PCI_MAIL_IERD                0x000000D2
#define V3_LB_MAIL_IEWR                 0x000000D4
#define V3_LB_MAIL_IERD                 0x000000D6
#define V3_MAIL_WR_STAT                 0x000000D8
#define V3_MAIL_RD_STAT                 0x000000DA
#define V3_QBA_MAP                      0x000000DC

/* PCI STATUS bits */
#define V3_PCI_STAT_PAR_ERR             BIT(15)
#define V3_PCI_STAT_SYS_ERR             BIT(14)
#define V3_PCI_STAT_M_ABORT_ERR         BIT(13)
#define V3_PCI_STAT_T_ABORT_ERR         BIT(12)

/* LB ISTAT bits */
#define V3_LB_ISTAT_MAILBOX             BIT(7)
#define V3_LB_ISTAT_PCI_RD              BIT(6)
#define V3_LB_ISTAT_PCI_WR              BIT(5)
#define V3_LB_ISTAT_PCI_INT             BIT(4)
#define V3_LB_ISTAT_PCI_PERR            BIT(3)
#define V3_LB_ISTAT_I2O_QWR             BIT(2)
#define V3_LB_ISTAT_DMA1                BIT(1)
#define V3_LB_ISTAT_DMA0                BIT(0)

/* PCI COMMAND bits */
#define V3_COMMAND_M_FBB_EN             BIT(9)
#define V3_COMMAND_M_SERR_EN            BIT(8)
#define V3_COMMAND_M_PAR_EN             BIT(6)
#define V3_COMMAND_M_MASTER_EN          BIT(2)
#define V3_COMMAND_M_MEM_EN             BIT(1)
#define V3_COMMAND_M_IO_EN              BIT(0)

/* SYSTEM bits */
#define V3_SYSTEM_M_RST_OUT             BIT(15)
#define V3_SYSTEM_M_LOCK                BIT(14)
#define V3_SYSTEM_UNLOCK                0xa05f

/* PCI CFG bits */
#define V3_PCI_CFG_M_I2O_EN             BIT(15)
#define V3_PCI_CFG_M_IO_REG_DIS         BIT(14)
#define V3_PCI_CFG_M_IO_DIS             BIT(13)
#define V3_PCI_CFG_M_EN3V               BIT(12)
#define V3_PCI_CFG_M_RETRY_EN           BIT(10)
#define V3_PCI_CFG_M_AD_LOW1            BIT(9)
#define V3_PCI_CFG_M_AD_LOW0            BIT(8)
/*
 * This is the value applied to C/BE[3:1], with bit 0 always held 0
 * during DMA access.
 */
#define V3_PCI_CFG_M_RTYPE_SHIFT        5
#define V3_PCI_CFG_M_WTYPE_SHIFT        1
#define V3_PCI_CFG_TYPE_DEFAULT         0x3

/* PCI BASE bits (PCI -> Local Bus) */
#define V3_PCI_BASE_M_ADR_BASE          0xFFF00000U
#define V3_PCI_BASE_M_ADR_BASEL         0x000FFF00U
#define V3_PCI_BASE_M_PREFETCH          BIT(3)
#define V3_PCI_BASE_M_TYPE              (3 << 1)
#define V3_PCI_BASE_M_IO                BIT(0)

/* PCI MAP bits (PCI -> Local bus) */
#define V3_PCI_MAP_M_MAP_ADR            0xFFF00000U
#define V3_PCI_MAP_M_RD_POST_INH        BIT(15)
#define V3_PCI_MAP_M_ROM_SIZE           (3 << 10)
#define V3_PCI_MAP_M_SWAP               (3 << 8)
#define V3_PCI_MAP_M_ADR_SIZE           0x000000F0U
#define V3_PCI_MAP_M_REG_EN             BIT(1)
#define V3_PCI_MAP_M_ENABLE             BIT(0)

/* LB_BASE0,1 bits (Local bus -> PCI) */
#define V3_LB_BASE_ADR_BASE             0xfff00000U
#define V3_LB_BASE_SWAP                 (3 << 8)
#define V3_LB_BASE_ADR_SIZE             (15 << 4)
#define V3_LB_BASE_PREFETCH             BIT(3)
#define V3_LB_BASE_ENABLE               BIT(0)

#define V3_LB_BASE_ADR_SIZE_1MB         (0 << 4)
#define V3_LB_BASE_ADR_SIZE_2MB         (1 << 4)
#define V3_LB_BASE_ADR_SIZE_4MB         (2 << 4)
#define V3_LB_BASE_ADR_SIZE_8MB         (3 << 4)
#define V3_LB_BASE_ADR_SIZE_16MB        (4 << 4)
#define V3_LB_BASE_ADR_SIZE_32MB        (5 << 4)
#define V3_LB_BASE_ADR_SIZE_64MB        (6 << 4)
#define V3_LB_BASE_ADR_SIZE_128MB       (7 << 4)
#define V3_LB_BASE_ADR_SIZE_256MB       (8 << 4)
#define V3_LB_BASE_ADR_SIZE_512MB       (9 << 4)
#define V3_LB_BASE_ADR_SIZE_1GB         (10 << 4)
#define V3_LB_BASE_ADR_SIZE_2GB         (11 << 4)

#define v3_addr_to_lb_base(a)   ((a) & V3_LB_BASE_ADR_BASE)

/* LB_MAP0,1 bits (Local bus -> PCI) */
#define V3_LB_MAP_MAP_ADR               0xfff0U
#define V3_LB_MAP_TYPE                  (7 << 1)
#define V3_LB_MAP_AD_LOW_EN             BIT(0)

#define V3_LB_MAP_TYPE_IACK             (0 << 1)
#define V3_LB_MAP_TYPE_IO               (1 << 1)
#define V3_LB_MAP_TYPE_MEM              (3 << 1)
#define V3_LB_MAP_TYPE_CONFIG           (5 << 1)
#define V3_LB_MAP_TYPE_MEM_MULTIPLE     (6 << 1)

#define v3_addr_to_lb_map(a)    (((a) >> 16) & V3_LB_MAP_MAP_ADR)

/* LB_BASE2 bits (Local bus -> PCI IO) */
#define V3_LB_BASE2_ADR_BASE            0xff00U
#define V3_LB_BASE2_SWAP_AUTO           (3 << 6)
#define V3_LB_BASE2_ENABLE              BIT(0)

#define v3_addr_to_lb_base2(a)  (((a) >> 16) & V3_LB_BASE2_ADR_BASE)

/* LB_MAP2 bits (Local bus -> PCI IO) */
#define V3_LB_MAP2_MAP_ADR              0xff00U

#define v3_addr_to_lb_map2(a)   (((a) >> 16) & V3_LB_MAP2_MAP_ADR)

/* FIFO priority bits */
#define V3_FIFO_PRIO_LOCAL              BIT(12)
#define V3_FIFO_PRIO_LB_RD1_FLUSH_EOB   BIT(10)
#define V3_FIFO_PRIO_LB_RD1_FLUSH_AP1   BIT(11)
#define V3_FIFO_PRIO_LB_RD1_FLUSH_ANY   (BIT(10)|BIT(11))
#define V3_FIFO_PRIO_LB_RD0_FLUSH_EOB   BIT(8)
#define V3_FIFO_PRIO_LB_RD0_FLUSH_AP1   BIT(9)
#define V3_FIFO_PRIO_LB_RD0_FLUSH_ANY   (BIT(8)|BIT(9))
#define V3_FIFO_PRIO_PCI                BIT(4)
#define V3_FIFO_PRIO_PCI_RD1_FLUSH_EOB  BIT(2)
#define V3_FIFO_PRIO_PCI_RD1_FLUSH_AP1  BIT(3)
#define V3_FIFO_PRIO_PCI_RD1_FLUSH_ANY  (BIT(2)|BIT(3))
#define V3_FIFO_PRIO_PCI_RD0_FLUSH_EOB  BIT(0)
#define V3_FIFO_PRIO_PCI_RD0_FLUSH_AP1  BIT(1)
#define V3_FIFO_PRIO_PCI_RD0_FLUSH_ANY  (BIT(0)|BIT(1))

/* Local bus configuration bits */
#define V3_LB_CFG_LB_TO_64_CYCLES       0x0000
#define V3_LB_CFG_LB_TO_256_CYCLES      BIT(13)
#define V3_LB_CFG_LB_TO_512_CYCLES      BIT(14)
#define V3_LB_CFG_LB_TO_1024_CYCLES     (BIT(13)|BIT(14))
#define V3_LB_CFG_LB_RST                BIT(12)
#define V3_LB_CFG_LB_PPC_RDY            BIT(11)
#define V3_LB_CFG_LB_LB_INT             BIT(10)
#define V3_LB_CFG_LB_ERR_EN             BIT(9)
#define V3_LB_CFG_LB_RDY_EN             BIT(8)
#define V3_LB_CFG_LB_BE_IMODE           BIT(7)
#define V3_LB_CFG_LB_BE_OMODE           BIT(6)
#define V3_LB_CFG_LB_ENDIAN             BIT(5)
#define V3_LB_CFG_LB_PARK_EN            BIT(4)
#define V3_LB_CFG_LB_FBB_DIS            BIT(2)

/* ARM Integrator-specific extended control registers */
#define INTEGRATOR_SC_PCI_OFFSET        0x18
#define INTEGRATOR_SC_PCI_ENABLE        BIT(0)
#define INTEGRATOR_SC_PCI_INTCLR        BIT(1)
#define INTEGRATOR_SC_LBFADDR_OFFSET    0x20
#define INTEGRATOR_SC_LBFCODE_OFFSET    0x24

struct v3_pci {
        struct device *dev;
        void __iomem *base;
        void __iomem *config_base;
        struct pci_bus *bus;
        u32 config_mem;
        u32 io_mem;
        u32 non_pre_mem;
        u32 pre_mem;
        phys_addr_t io_bus_addr;
        phys_addr_t non_pre_bus_addr;
        phys_addr_t pre_bus_addr;
        struct regmap *map;
};

/*
 * The V3 PCI interface chip in Integrator provides several windows from
 * local bus memory into the PCI memory areas. Unfortunately, there
 * are not really enough windows for our usage, therefore we reuse
 * one of the windows for access to PCI configuration space. On the
 * Integrator/AP, the memory map is as follows:
 *
 * Local Bus Memory         Usage
 *
 * 40000000 - 4FFFFFFF      PCI memory.  256M non-prefetchable
 * 50000000 - 5FFFFFFF      PCI memory.  256M prefetchable
 * 60000000 - 60FFFFFF      PCI IO.  16M
 * 61000000 - 61FFFFFF      PCI Configuration. 16M
 *
 * There are three V3 windows, each described by a pair of V3 registers.
 * These are LB_BASE0/LB_MAP0, LB_BASE1/LB_MAP1 and LB_BASE2/LB_MAP2.
 * Base0 and Base1 can be used for any type of PCI memory access.   Base2
 * can be used either for PCI I/O or for I20 accesses.  By default, uHAL
 * uses this only for PCI IO space.
 *
 * Normally these spaces are mapped using the following base registers:
 *
 * Usage Local Bus Memory         Base/Map registers used
 *
 * Mem   40000000 - 4FFFFFFF      LB_BASE0/LB_MAP0
 * Mem   50000000 - 5FFFFFFF      LB_BASE1/LB_MAP1
 * IO    60000000 - 60FFFFFF      LB_BASE2/LB_MAP2
 * Cfg   61000000 - 61FFFFFF
 *
 * This means that I20 and PCI configuration space accesses will fail.
 * When PCI configuration accesses are needed (via the uHAL PCI
 * configuration space primitives) we must remap the spaces as follows:
 *
 * Usage Local Bus Memory         Base/Map registers used
 *
 * Mem   40000000 - 4FFFFFFF      LB_BASE0/LB_MAP0
 * Mem   50000000 - 5FFFFFFF      LB_BASE0/LB_MAP0
 * IO    60000000 - 60FFFFFF      LB_BASE2/LB_MAP2
 * Cfg   61000000 - 61FFFFFF      LB_BASE1/LB_MAP1
 *
 * To make this work, the code depends on overlapping windows working.
 * The V3 chip translates an address by checking its range within
 * each of the BASE/MAP pairs in turn (in ascending register number
 * order).  It will use the first matching pair.   So, for example,
 * if the same address is mapped by both LB_BASE0/LB_MAP0 and
 * LB_BASE1/LB_MAP1, the V3 will use the translation from
 * LB_BASE0/LB_MAP0.
 *
 * To allow PCI Configuration space access, the code enlarges the
 * window mapped by LB_BASE0/LB_MAP0 from 256M to 512M.  This occludes
 * the windows currently mapped by LB_BASE1/LB_MAP1 so that it can
 * be remapped for use by configuration cycles.
 *
 * At the end of the PCI Configuration space accesses,
 * LB_BASE1/LB_MAP1 is reset to map PCI Memory.  Finally the window
 * mapped by LB_BASE0/LB_MAP0 is reduced in size from 512M to 256M to
 * reveal the now restored LB_BASE1/LB_MAP1 window.
 *
 * NOTE: We do not set up I2O mapping.  I suspect that this is only
 * for an intelligent (target) device.  Using I2O disables most of
 * the mappings into PCI memory.
 */
static void __iomem *v3_map_bus(struct pci_bus *bus,
                                unsigned int devfn, int offset)
{
        struct v3_pci *v3 = bus->sysdata;
        unsigned int address, mapaddress, busnr;

        busnr = bus->number;
        if (busnr == 0) {
                int slot = PCI_SLOT(devfn);

                /*
                 * local bus segment so need a type 0 config cycle
                 *
                 * build the PCI configuration "address" with one-hot in
                 * A31-A11
                 *
                 * mapaddress:
                 *  3:1 = config cycle (101)
                 *  0   = PCI A1 & A0 are 0 (0)
                 */
                address = PCI_FUNC(devfn) << 8;
                mapaddress = V3_LB_MAP_TYPE_CONFIG;

                if (slot > 12)
                        /*
                         * high order bits are handled by the MAP register
                         */
                        mapaddress |= BIT(slot - 5);
                else
                        /*
                         * low order bits handled directly in the address
                         */
                        address |= BIT(slot + 11);
        } else {
                /*
                 * not the local bus segment so need a type 1 config cycle
                 *
                 * address:
                 *  23:16 = bus number
                 *  15:11 = slot number (7:3 of devfn)
                 *  10:8  = func number (2:0 of devfn)
                 *
                 * mapaddress:
                 *  3:1 = config cycle (101)
                 *  0   = PCI A1 & A0 from host bus (1)
                 */
                mapaddress = V3_LB_MAP_TYPE_CONFIG | V3_LB_MAP_AD_LOW_EN;
                address = (busnr << 16) | (devfn << 8);
        }

        /*
         * Set up base0 to see all 512Mbytes of memory space (not
         * prefetchable), this frees up base1 for re-use by
         * configuration memory
         */
        writel(v3_addr_to_lb_base(v3->non_pre_mem) |
               V3_LB_BASE_ADR_SIZE_512MB | V3_LB_BASE_ENABLE,
               v3->base + V3_LB_BASE0);

        /*
         * Set up base1/map1 to point into configuration space.
         * The config mem is always 16MB.
         */
        writel(v3_addr_to_lb_base(v3->config_mem) |
               V3_LB_BASE_ADR_SIZE_16MB | V3_LB_BASE_ENABLE,
               v3->base + V3_LB_BASE1);
        writew(mapaddress, v3->base + V3_LB_MAP1);

        return v3->config_base + address + offset;
}

static void v3_unmap_bus(struct v3_pci *v3)
{
        /*
         * Reassign base1 for use by prefetchable PCI memory
         */
        writel(v3_addr_to_lb_base(v3->pre_mem) |
               V3_LB_BASE_ADR_SIZE_256MB | V3_LB_BASE_PREFETCH |
               V3_LB_BASE_ENABLE,
               v3->base + V3_LB_BASE1);
        writew(v3_addr_to_lb_map(v3->pre_bus_addr) |
               V3_LB_MAP_TYPE_MEM, /* was V3_LB_MAP_TYPE_MEM_MULTIPLE */
               v3->base + V3_LB_MAP1);

        /*
         * And shrink base0 back to a 256M window (NOTE: MAP0 already correct)
         */
        writel(v3_addr_to_lb_base(v3->non_pre_mem) |
               V3_LB_BASE_ADR_SIZE_256MB | V3_LB_BASE_ENABLE,
               v3->base + V3_LB_BASE0);
}

static int v3_pci_read_config(struct pci_bus *bus, unsigned int fn,
                              int config, int size, u32 *value)
{
        struct v3_pci *v3 = bus->sysdata;
        int ret;

        dev_dbg(&bus->dev,
                "[read]  slt: %.2d, fnc: %d, cnf: 0x%.2X, val (%d bytes): 0x%.8X\n",
                PCI_SLOT(fn), PCI_FUNC(fn), config, size, *value);
        ret = pci_generic_config_read(bus, fn, config, size, value);
        v3_unmap_bus(v3);
        return ret;
}

static int v3_pci_write_config(struct pci_bus *bus, unsigned int fn,
                                    int config, int size, u32 value)
{
        struct v3_pci *v3 = bus->sysdata;
        int ret;

        dev_dbg(&bus->dev,
                "[write] slt: %.2d, fnc: %d, cnf: 0x%.2X, val (%d bytes): 0x%.8X\n",
                PCI_SLOT(fn), PCI_FUNC(fn), config, size, value);
        ret = pci_generic_config_write(bus, fn, config, size, value);
        v3_unmap_bus(v3);
        return ret;
}

static struct pci_ops v3_pci_ops = {
        .map_bus = v3_map_bus,
        .read = v3_pci_read_config,
        .write = v3_pci_write_config,
};

static irqreturn_t v3_irq(int irq, void *data)
{
        struct v3_pci *v3 = data;
        struct device *dev = v3->dev;
        u32 status;

        status = readw(v3->base + V3_PCI_STAT);
        if (status & V3_PCI_STAT_PAR_ERR)
                dev_err(dev, "parity error interrupt\n");
        if (status & V3_PCI_STAT_SYS_ERR)
                dev_err(dev, "system error interrupt\n");
        if (status & V3_PCI_STAT_M_ABORT_ERR)
                dev_err(dev, "master abort error interrupt\n");
        if (status & V3_PCI_STAT_T_ABORT_ERR)
                dev_err(dev, "target abort error interrupt\n");
        writew(status, v3->base + V3_PCI_STAT);

        status = readb(v3->base + V3_LB_ISTAT);
        if (status & V3_LB_ISTAT_MAILBOX)
                dev_info(dev, "PCI mailbox interrupt\n");
        if (status & V3_LB_ISTAT_PCI_RD)
                dev_err(dev, "PCI target LB->PCI READ abort interrupt\n");
        if (status & V3_LB_ISTAT_PCI_WR)
                dev_err(dev, "PCI target LB->PCI WRITE abort interrupt\n");
        if (status &  V3_LB_ISTAT_PCI_INT)
                dev_info(dev, "PCI pin interrupt\n");
        if (status & V3_LB_ISTAT_PCI_PERR)
                dev_err(dev, "PCI parity error interrupt\n");
        if (status & V3_LB_ISTAT_I2O_QWR)
                dev_info(dev, "I2O inbound post queue interrupt\n");
        if (status & V3_LB_ISTAT_DMA1)
                dev_info(dev, "DMA channel 1 interrupt\n");
        if (status & V3_LB_ISTAT_DMA0)
                dev_info(dev, "DMA channel 0 interrupt\n");
        /* Clear all possible interrupts on the local bus */
        writeb(0, v3->base + V3_LB_ISTAT);
        if (v3->map)
                regmap_write(v3->map, INTEGRATOR_SC_PCI_OFFSET,
                             INTEGRATOR_SC_PCI_ENABLE |
                             INTEGRATOR_SC_PCI_INTCLR);

        return IRQ_HANDLED;
}

static int v3_integrator_init(struct v3_pci *v3)
{
        unsigned int val;

        v3->map =
                syscon_regmap_lookup_by_compatible("arm,integrator-ap-syscon");
        if (IS_ERR(v3->map)) {
                dev_err(v3->dev, "no syscon\n");
                return -ENODEV;
        }

        regmap_read(v3->map, INTEGRATOR_SC_PCI_OFFSET, &val);
        /* Take the PCI bridge out of reset, clear IRQs */
        regmap_write(v3->map, INTEGRATOR_SC_PCI_OFFSET,
                     INTEGRATOR_SC_PCI_ENABLE |
                     INTEGRATOR_SC_PCI_INTCLR);

        if (!(val & INTEGRATOR_SC_PCI_ENABLE)) {
                /* If we were in reset we need to sleep a bit */
                msleep(230);

                /* Set the physical base for the controller itself */
                writel(0x6200, v3->base + V3_LB_IO_BASE);

                /* Wait for the mailbox to settle after reset */
                do {
                        writeb(0xaa, v3->base + V3_MAIL_DATA);
                        writeb(0x55, v3->base + V3_MAIL_DATA + 4);
                } while (readb(v3->base + V3_MAIL_DATA) != 0xaa &&
                         readb(v3->base + V3_MAIL_DATA) != 0x55);
        }

        dev_info(v3->dev, "initialized PCI V3 Integrator/AP integration\n");

        return 0;
}

static int v3_pci_setup_resource(struct v3_pci *v3,
                                 resource_size_t io_base,
                                 struct pci_host_bridge *host,
                                 struct resource_entry *win)
{
        struct device *dev = v3->dev;
        struct resource *mem;
        struct resource *io;
        int ret;

        switch (resource_type(win->res)) {
        case IORESOURCE_IO:
                io = win->res;
                io->name = "V3 PCI I/O";
                v3->io_mem = io_base;
                v3->io_bus_addr = io->start - win->offset;
                dev_dbg(dev, "I/O window %pR, bus addr %pap\n",
                        io, &v3->io_bus_addr);
                ret = pci_remap_iospace(io, io_base);
                if (ret) {
                        dev_warn(dev,
                                 "error %d: failed to map resource %pR\n",
                                 ret, io);
                        return ret;
                }
                /* Setup window 2 - PCI I/O */
                writel(v3_addr_to_lb_base2(v3->io_mem) |
                       V3_LB_BASE2_ENABLE,
                       v3->base + V3_LB_BASE2);
                writew(v3_addr_to_lb_map2(v3->io_bus_addr),
                       v3->base + V3_LB_MAP2);
                break;
        case IORESOURCE_MEM:
                mem = win->res;
                if (mem->flags & IORESOURCE_PREFETCH) {
                        mem->name = "V3 PCI PRE-MEM";
                        v3->pre_mem = mem->start;
                        v3->pre_bus_addr = mem->start - win->offset;
                        dev_dbg(dev, "PREFETCHABLE MEM window %pR, bus addr %pap\n",
                                mem, &v3->pre_bus_addr);
                        if (resource_size(mem) != SZ_256M) {
                                dev_err(dev, "prefetchable memory range is not 256MB\n");
                                return -EINVAL;
                        }
                        if (v3->non_pre_mem &&
                            (mem->start != v3->non_pre_mem + SZ_256M)) {
                                dev_err(dev,
                                        "prefetchable memory is not adjacent to non-prefetchable memory\n");
                                return -EINVAL;
                        }
                        /* Setup window 1 - PCI prefetchable memory */
                        writel(v3_addr_to_lb_base(v3->pre_mem) |
                               V3_LB_BASE_ADR_SIZE_256MB |
                               V3_LB_BASE_PREFETCH |
                               V3_LB_BASE_ENABLE,
                               v3->base + V3_LB_BASE1);
                        writew(v3_addr_to_lb_map(v3->pre_bus_addr) |
                               V3_LB_MAP_TYPE_MEM, /* Was V3_LB_MAP_TYPE_MEM_MULTIPLE */
                               v3->base + V3_LB_MAP1);
                } else {
                        mem->name = "V3 PCI NON-PRE-MEM";
                        v3->non_pre_mem = mem->start;
                        v3->non_pre_bus_addr = mem->start - win->offset;
                        dev_dbg(dev, "NON-PREFETCHABLE MEM window %pR, bus addr %pap\n",
                                mem, &v3->non_pre_bus_addr);
                        if (resource_size(mem) != SZ_256M) {
                                dev_err(dev,
                                        "non-prefetchable memory range is not 256MB\n");
                                return -EINVAL;
                        }
                        /* Setup window 0 - PCI non-prefetchable memory */
                        writel(v3_addr_to_lb_base(v3->non_pre_mem) |
                               V3_LB_BASE_ADR_SIZE_256MB |
                               V3_LB_BASE_ENABLE,
                               v3->base + V3_LB_BASE0);
                        writew(v3_addr_to_lb_map(v3->non_pre_bus_addr) |
                               V3_LB_MAP_TYPE_MEM,
                               v3->base + V3_LB_MAP0);
                }
                break;
        case IORESOURCE_BUS:
                dev_dbg(dev, "BUS %pR\n", win->res);
                host->busnr = win->res->start;
                break;
        default:
                dev_info(dev, "Unknown resource type %lu\n",
                         resource_type(win->res));
                break;
        }

        return 0;
}

static int v3_get_dma_range_config(struct v3_pci *v3,
                                   struct of_pci_range *range,
                                   u32 *pci_base, u32 *pci_map)
{
        struct device *dev = v3->dev;
        u64 cpu_end = range->cpu_addr + range->size - 1;
        u64 pci_end = range->pci_addr + range->size - 1;
        u32 val;

        if (range->pci_addr & ~V3_PCI_BASE_M_ADR_BASE) {
                dev_err(dev, "illegal range, only PCI bits 31..20 allowed\n");
                return -EINVAL;
        }
        val = ((u32)range->pci_addr) & V3_PCI_BASE_M_ADR_BASE;
        *pci_base = val;

        if (range->cpu_addr & ~V3_PCI_MAP_M_MAP_ADR) {
                dev_err(dev, "illegal range, only CPU bits 31..20 allowed\n");
                return -EINVAL;
        }
        val = ((u32)range->cpu_addr) & V3_PCI_MAP_M_MAP_ADR;

        switch (range->size) {
        case SZ_1M:
                val |= V3_LB_BASE_ADR_SIZE_1MB;
                break;
        case SZ_2M:
                val |= V3_LB_BASE_ADR_SIZE_2MB;
                break;
        case SZ_4M:
                val |= V3_LB_BASE_ADR_SIZE_4MB;
                break;
        case SZ_8M:
                val |= V3_LB_BASE_ADR_SIZE_8MB;
                break;
        case SZ_16M:
                val |= V3_LB_BASE_ADR_SIZE_16MB;
                break;
        case SZ_32M:
                val |= V3_LB_BASE_ADR_SIZE_32MB;
                break;
        case SZ_64M:
                val |= V3_LB_BASE_ADR_SIZE_64MB;
                break;
        case SZ_128M:
                val |= V3_LB_BASE_ADR_SIZE_128MB;
                break;
        case SZ_256M:
                val |= V3_LB_BASE_ADR_SIZE_256MB;
                break;
        case SZ_512M:
                val |= V3_LB_BASE_ADR_SIZE_512MB;
                break;
        case SZ_1G:
                val |= V3_LB_BASE_ADR_SIZE_1GB;
                break;
        case SZ_2G:
                val |= V3_LB_BASE_ADR_SIZE_2GB;
                break;
        default:
                dev_err(v3->dev, "illegal dma memory chunk size\n");
                return -EINVAL;
                break;
        }
        val |= V3_PCI_MAP_M_REG_EN | V3_PCI_MAP_M_ENABLE;
        *pci_map = val;

        dev_dbg(dev,
                "DMA MEM CPU: 0x%016llx -> 0x%016llx => "
                "PCI: 0x%016llx -> 0x%016llx base %08x map %08x\n",
                range->cpu_addr, cpu_end,
                range->pci_addr, pci_end,
                *pci_base, *pci_map);

        return 0;
}

static int v3_pci_parse_map_dma_ranges(struct v3_pci *v3,
                                       struct device_node *np)
{
        struct of_pci_range range;
        struct of_pci_range_parser parser;
        struct device *dev = v3->dev;
        int i = 0;

        if (of_pci_dma_range_parser_init(&parser, np)) {
                dev_err(dev, "missing dma-ranges property\n");
                return -EINVAL;
        }

        /*
         * Get the dma-ranges from the device tree
         */
        for_each_of_pci_range(&parser, &range) {
                int ret;
                u32 pci_base, pci_map;

                ret = v3_get_dma_range_config(v3, &range, &pci_base, &pci_map);
                if (ret)
                        return ret;

                if (i == 0) {
                        writel(pci_base, v3->base + V3_PCI_BASE0);
                        writel(pci_map, v3->base + V3_PCI_MAP0);
                } else if (i == 1) {
                        writel(pci_base, v3->base + V3_PCI_BASE1);
                        writel(pci_map, v3->base + V3_PCI_MAP1);
                } else {
                        dev_err(dev, "too many ranges, only two supported\n");
                        dev_err(dev, "range %d ignored\n", i);
                }
                i++;
        }
        return 0;
}

static int v3_pci_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        resource_size_t io_base;
        struct resource *regs;
        struct resource_entry *win;
        struct v3_pci *v3;
        struct pci_host_bridge *host;
        struct clk *clk;
        u16 val;
        int irq;
        int ret;
        LIST_HEAD(res);

        host = pci_alloc_host_bridge(sizeof(*v3));
        if (!host)
                return -ENOMEM;

        host->dev.parent = dev;
        host->ops = &v3_pci_ops;
        host->busnr = 0;
        host->msi = NULL;
        host->map_irq = of_irq_parse_and_map_pci;
        host->swizzle_irq = pci_common_swizzle;
        v3 = pci_host_bridge_priv(host);
        host->sysdata = v3;
        v3->dev = dev;

        /* Get and enable host clock */
        clk = devm_clk_get(dev, NULL);
        if (IS_ERR(clk)) {
                dev_err(dev, "clock not found\n");
                return PTR_ERR(clk);
        }
        ret = clk_prepare_enable(clk);
        if (ret) {
                dev_err(dev, "unable to enable clock\n");
                return ret;
        }

        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        v3->base = devm_ioremap_resource(dev, regs);
        if (IS_ERR(v3->base))
                return PTR_ERR(v3->base);
        /*
         * The hardware has a register with the physical base address
         * of the V3 controller itself, verify that this is the same
         * as the physical memory we've remapped it from.
         */
        if (readl(v3->base + V3_LB_IO_BASE) != (regs->start >> 16))
                dev_err(dev, "V3_LB_IO_BASE = %08x but device is @%pR\n",
                        readl(v3->base + V3_LB_IO_BASE), regs);

        /* Configuration space is 16MB directly mapped */
        regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        if (resource_size(regs) != SZ_16M) {
                dev_err(dev, "config mem is not 16MB!\n");
                return -EINVAL;
        }
        v3->config_mem = regs->start;
        v3->config_base = devm_ioremap_resource(dev, regs);
        if (IS_ERR(v3->config_base))
                return PTR_ERR(v3->config_base);

        ret = of_pci_get_host_bridge_resources(np, 0, 0xff, &res, &io_base);
        if (ret)
                return ret;

        ret = devm_request_pci_bus_resources(dev, &res);
        if (ret)
                return ret;

        /* Get and request error IRQ resource */
        irq = platform_get_irq(pdev, 0);
        if (irq <= 0) {
                dev_err(dev, "unable to obtain PCIv3 error IRQ\n");
                return -ENODEV;
        }
        ret = devm_request_irq(dev, irq, v3_irq, 0,
                        "PCIv3 error", v3);
        if (ret < 0) {
                dev_err(dev,
                        "unable to request PCIv3 error IRQ %d (%d)\n",
                        irq, ret);
                return ret;
        }

        /*
         * Unlock V3 registers, but only if they were previously locked.
         */
        if (readw(v3->base + V3_SYSTEM) & V3_SYSTEM_M_LOCK)
                writew(V3_SYSTEM_UNLOCK, v3->base + V3_SYSTEM);

        /* Disable all slave access while we set up the windows */
        val = readw(v3->base + V3_PCI_CMD);
        val &= ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);
        writew(val, v3->base + V3_PCI_CMD);

        /* Put the PCI bus into reset */
        val = readw(v3->base + V3_SYSTEM);
        val &= ~V3_SYSTEM_M_RST_OUT;
        writew(val, v3->base + V3_SYSTEM);

        /* Retry until we're ready */
        val = readw(v3->base + V3_PCI_CFG);
        val |= V3_PCI_CFG_M_RETRY_EN;
        writew(val, v3->base + V3_PCI_CFG);

        /* Set up the local bus protocol */
        val = readw(v3->base + V3_LB_CFG);
        val |= V3_LB_CFG_LB_BE_IMODE; /* Byte enable input */
        val |= V3_LB_CFG_LB_BE_OMODE; /* Byte enable output */
        val &= ~V3_LB_CFG_LB_ENDIAN; /* Little endian */
        val &= ~V3_LB_CFG_LB_PPC_RDY; /* TODO: when using on PPC403Gx, set to 1 */
        writew(val, v3->base + V3_LB_CFG);

        /* Enable the PCI bus master */
        val = readw(v3->base + V3_PCI_CMD);
        val |= PCI_COMMAND_MASTER;
        writew(val, v3->base + V3_PCI_CMD);

        /* Get the I/O and memory ranges from DT */
        resource_list_for_each_entry(win, &res) {
                ret = v3_pci_setup_resource(v3, io_base, host, win);
                if (ret) {
                        dev_err(dev, "error setting up resources\n");
                        return ret;
                }
        }
        ret = v3_pci_parse_map_dma_ranges(v3, np);
        if (ret)
                return ret;

        /*
         * Disable PCI to host IO cycles, enable I/O buffers @3.3V,
         * set AD_LOW0 to 1 if one of the LB_MAP registers choose
         * to use this (should be unused).
         */
        writel(0x00000000, v3->base + V3_PCI_IO_BASE);
        val = V3_PCI_CFG_M_IO_REG_DIS | V3_PCI_CFG_M_IO_DIS |
                V3_PCI_CFG_M_EN3V | V3_PCI_CFG_M_AD_LOW0;
        /*
         * DMA read and write from PCI bus commands types
         */
        val |=  V3_PCI_CFG_TYPE_DEFAULT << V3_PCI_CFG_M_RTYPE_SHIFT;
        val |=  V3_PCI_CFG_TYPE_DEFAULT << V3_PCI_CFG_M_WTYPE_SHIFT;
        writew(val, v3->base + V3_PCI_CFG);

        /*
         * Set the V3 FIFO such that writes have higher priority than
         * reads, and local bus write causes local bus read fifo flush
         * on aperture 1. Same for PCI.
         */
        writew(V3_FIFO_PRIO_LB_RD1_FLUSH_AP1 |
               V3_FIFO_PRIO_LB_RD0_FLUSH_AP1 |
               V3_FIFO_PRIO_PCI_RD1_FLUSH_AP1 |
               V3_FIFO_PRIO_PCI_RD0_FLUSH_AP1,
               v3->base + V3_FIFO_PRIORITY);


        /*
         * Clear any error interrupts, and enable parity and write error
         * interrupts
         */
        writeb(0, v3->base + V3_LB_ISTAT);
        val = readw(v3->base + V3_LB_CFG);
        val |= V3_LB_CFG_LB_LB_INT;
        writew(val, v3->base + V3_LB_CFG);
        writeb(V3_LB_ISTAT_PCI_WR | V3_LB_ISTAT_PCI_PERR,
               v3->base + V3_LB_IMASK);

        /* Special Integrator initialization */
        if (of_device_is_compatible(np, "arm,integrator-ap-pci")) {
                ret = v3_integrator_init(v3);
                if (ret)
                        return ret;
        }

        /* Post-init: enable PCI memory and invalidate (master already on) */
        val = readw(v3->base + V3_PCI_CMD);
        val |= PCI_COMMAND_MEMORY | PCI_COMMAND_INVALIDATE;
        writew(val, v3->base + V3_PCI_CMD);

        /* Clear pending interrupts */
        writeb(0, v3->base + V3_LB_ISTAT);
        /* Read or write errors and parity errors cause interrupts */
        writeb(V3_LB_ISTAT_PCI_RD | V3_LB_ISTAT_PCI_WR | V3_LB_ISTAT_PCI_PERR,
               v3->base + V3_LB_IMASK);

        /* Take the PCI bus out of reset so devices can initialize */
        val = readw(v3->base + V3_SYSTEM);
        val |= V3_SYSTEM_M_RST_OUT;
        writew(val, v3->base + V3_SYSTEM);

        /*
         * Re-lock the system register.
         */
        val = readw(v3->base + V3_SYSTEM);
        val |= V3_SYSTEM_M_LOCK;
        writew(val, v3->base + V3_SYSTEM);

        list_splice_init(&res, &host->windows);
        ret = pci_scan_root_bus_bridge(host);
        if (ret) {
                dev_err(dev, "failed to register host: %d\n", ret);
                return ret;
        }
        v3->bus = host->bus;

        pci_bus_assign_resources(v3->bus);
        pci_bus_add_devices(v3->bus);

        return 0;
}

static const struct of_device_id v3_pci_of_match[] = {
        {
                .compatible = "v3,v360epc-pci",
        },
        {},
};

static struct platform_driver v3_pci_driver = {
        .driver = {
                .name = "pci-v3-semi",
                .of_match_table = of_match_ptr(v3_pci_of_match),
                .suppress_bind_attrs = true,
        },
        .probe  = v3_pci_probe,
};
builtin_platform_driver(v3_pci_driver);