root/arch/mips/pci/pci-ar71xx.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Atheros AR71xx PCI host controller driver
 *
 *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
 *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
 *
 *  Parts of this file are based on Atheros' 2.6.15 BSP
 */

#include <linux/resource.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/pci.h>
#include <linux/pci_regs.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/platform_device.h>

#include <asm/mach-ath79/ar71xx_regs.h>
#include <asm/mach-ath79/ath79.h>

#define AR71XX_PCI_REG_CRP_AD_CBE       0x00
#define AR71XX_PCI_REG_CRP_WRDATA       0x04
#define AR71XX_PCI_REG_CRP_RDDATA       0x08
#define AR71XX_PCI_REG_CFG_AD           0x0c
#define AR71XX_PCI_REG_CFG_CBE          0x10
#define AR71XX_PCI_REG_CFG_WRDATA       0x14
#define AR71XX_PCI_REG_CFG_RDDATA       0x18
#define AR71XX_PCI_REG_PCI_ERR          0x1c
#define AR71XX_PCI_REG_PCI_ERR_ADDR     0x20
#define AR71XX_PCI_REG_AHB_ERR          0x24
#define AR71XX_PCI_REG_AHB_ERR_ADDR     0x28

#define AR71XX_PCI_CRP_CMD_WRITE        0x00010000
#define AR71XX_PCI_CRP_CMD_READ         0x00000000
#define AR71XX_PCI_CFG_CMD_READ         0x0000000a
#define AR71XX_PCI_CFG_CMD_WRITE        0x0000000b

#define AR71XX_PCI_INT_CORE             BIT(4)
#define AR71XX_PCI_INT_DEV2             BIT(2)
#define AR71XX_PCI_INT_DEV1             BIT(1)
#define AR71XX_PCI_INT_DEV0             BIT(0)

#define AR71XX_PCI_IRQ_COUNT            5

struct ar71xx_pci_controller {
        void __iomem *cfg_base;
        int irq;
        int irq_base;
        struct pci_controller pci_ctrl;
        struct resource io_res;
        struct resource mem_res;
};

/* Byte lane enable bits */
static const u8 ar71xx_pci_ble_table[4][4] = {
        {0x0, 0xf, 0xf, 0xf},
        {0xe, 0xd, 0xb, 0x7},
        {0xc, 0xf, 0x3, 0xf},
        {0xf, 0xf, 0xf, 0xf},
};

static const u32 ar71xx_pci_read_mask[8] = {
        0, 0xff, 0xffff, 0, 0xffffffff, 0, 0, 0
};

static inline u32 ar71xx_pci_get_ble(int where, int size, int local)
{
        u32 t;

        t = ar71xx_pci_ble_table[size & 3][where & 3];
        BUG_ON(t == 0xf);
        t <<= (local) ? 20 : 4;

        return t;
}

static inline u32 ar71xx_pci_bus_addr(struct pci_bus *bus, unsigned int devfn,
                                      int where)
{
        u32 ret;

        if (!bus->number) {
                /* type 0 */
                ret = (1 << PCI_SLOT(devfn)) | (PCI_FUNC(devfn) << 8) |
                      (where & ~3);
        } else {
                /* type 1 */
                ret = (bus->number << 16) | (PCI_SLOT(devfn) << 11) |
                      (PCI_FUNC(devfn) << 8) | (where & ~3) | 1;
        }

        return ret;
}

static inline struct ar71xx_pci_controller *
pci_bus_to_ar71xx_controller(struct pci_bus *bus)
{
        struct pci_controller *hose;

        hose = (struct pci_controller *) bus->sysdata;
        return container_of(hose, struct ar71xx_pci_controller, pci_ctrl);
}

static int ar71xx_pci_check_error(struct ar71xx_pci_controller *apc, int quiet)
{
        void __iomem *base = apc->cfg_base;
        u32 pci_err;
        u32 ahb_err;

        pci_err = __raw_readl(base + AR71XX_PCI_REG_PCI_ERR) & 3;
        if (pci_err) {
                if (!quiet) {
                        u32 addr;

                        addr = __raw_readl(base + AR71XX_PCI_REG_PCI_ERR_ADDR);
                        pr_crit("ar71xx: %s bus error %d at addr 0x%x\n",
                                "PCI", pci_err, addr);
                }

                /* clear PCI error status */
                __raw_writel(pci_err, base + AR71XX_PCI_REG_PCI_ERR);
        }

        ahb_err = __raw_readl(base + AR71XX_PCI_REG_AHB_ERR) & 1;
        if (ahb_err) {
                if (!quiet) {
                        u32 addr;

                        addr = __raw_readl(base + AR71XX_PCI_REG_AHB_ERR_ADDR);
                        pr_crit("ar71xx: %s bus error %d at addr 0x%x\n",
                                "AHB", ahb_err, addr);
                }

                /* clear AHB error status */
                __raw_writel(ahb_err, base + AR71XX_PCI_REG_AHB_ERR);
        }

        return !!(ahb_err | pci_err);
}

static inline void ar71xx_pci_local_write(struct ar71xx_pci_controller *apc,
                                          int where, int size, u32 value)
{
        void __iomem *base = apc->cfg_base;
        u32 ad_cbe;

        value = value << (8 * (where & 3));

        ad_cbe = AR71XX_PCI_CRP_CMD_WRITE | (where & ~3);
        ad_cbe |= ar71xx_pci_get_ble(where, size, 1);

        __raw_writel(ad_cbe, base + AR71XX_PCI_REG_CRP_AD_CBE);
        __raw_writel(value, base + AR71XX_PCI_REG_CRP_WRDATA);
}

static inline int ar71xx_pci_set_cfgaddr(struct pci_bus *bus,
                                         unsigned int devfn,
                                         int where, int size, u32 cmd)
{
        struct ar71xx_pci_controller *apc = pci_bus_to_ar71xx_controller(bus);
        void __iomem *base = apc->cfg_base;
        u32 addr;

        addr = ar71xx_pci_bus_addr(bus, devfn, where);

        __raw_writel(addr, base + AR71XX_PCI_REG_CFG_AD);
        __raw_writel(cmd | ar71xx_pci_get_ble(where, size, 0),
                     base + AR71XX_PCI_REG_CFG_CBE);

        return ar71xx_pci_check_error(apc, 1);
}

static int ar71xx_pci_read_config(struct pci_bus *bus, unsigned int devfn,
                                  int where, int size, u32 *value)
{
        struct ar71xx_pci_controller *apc = pci_bus_to_ar71xx_controller(bus);
        void __iomem *base = apc->cfg_base;
        u32 data;
        int err;
        int ret;

        ret = PCIBIOS_SUCCESSFUL;
        data = ~0;

        err = ar71xx_pci_set_cfgaddr(bus, devfn, where, size,
                                     AR71XX_PCI_CFG_CMD_READ);
        if (err)
                ret = PCIBIOS_DEVICE_NOT_FOUND;
        else
                data = __raw_readl(base + AR71XX_PCI_REG_CFG_RDDATA);

        *value = (data >> (8 * (where & 3))) & ar71xx_pci_read_mask[size & 7];

        return ret;
}

static int ar71xx_pci_write_config(struct pci_bus *bus, unsigned int devfn,
                                   int where, int size, u32 value)
{
        struct ar71xx_pci_controller *apc = pci_bus_to_ar71xx_controller(bus);
        void __iomem *base = apc->cfg_base;
        int err;
        int ret;

        value = value << (8 * (where & 3));
        ret = PCIBIOS_SUCCESSFUL;

        err = ar71xx_pci_set_cfgaddr(bus, devfn, where, size,
                                     AR71XX_PCI_CFG_CMD_WRITE);
        if (err)
                ret = PCIBIOS_DEVICE_NOT_FOUND;
        else
                __raw_writel(value, base + AR71XX_PCI_REG_CFG_WRDATA);

        return ret;
}

static struct pci_ops ar71xx_pci_ops = {
        .read   = ar71xx_pci_read_config,
        .write  = ar71xx_pci_write_config,
};

static void ar71xx_pci_irq_handler(struct irq_desc *desc)
{
        struct ar71xx_pci_controller *apc;
        void __iomem *base = ath79_reset_base;
        u32 pending;

        apc = irq_desc_get_handler_data(desc);

        pending = __raw_readl(base + AR71XX_RESET_REG_PCI_INT_STATUS) &
                  __raw_readl(base + AR71XX_RESET_REG_PCI_INT_ENABLE);

        if (pending & AR71XX_PCI_INT_DEV0)
                generic_handle_irq(apc->irq_base + 0);

        else if (pending & AR71XX_PCI_INT_DEV1)
                generic_handle_irq(apc->irq_base + 1);

        else if (pending & AR71XX_PCI_INT_DEV2)
                generic_handle_irq(apc->irq_base + 2);

        else if (pending & AR71XX_PCI_INT_CORE)
                generic_handle_irq(apc->irq_base + 4);

        else
                spurious_interrupt();
}

static void ar71xx_pci_irq_unmask(struct irq_data *d)
{
        struct ar71xx_pci_controller *apc;
        unsigned int irq;
        void __iomem *base = ath79_reset_base;
        u32 t;

        apc = irq_data_get_irq_chip_data(d);
        irq = d->irq - apc->irq_base;

        t = __raw_readl(base + AR71XX_RESET_REG_PCI_INT_ENABLE);
        __raw_writel(t | (1 << irq), base + AR71XX_RESET_REG_PCI_INT_ENABLE);

        /* flush write */
        __raw_readl(base + AR71XX_RESET_REG_PCI_INT_ENABLE);
}

static void ar71xx_pci_irq_mask(struct irq_data *d)
{
        struct ar71xx_pci_controller *apc;
        unsigned int irq;
        void __iomem *base = ath79_reset_base;
        u32 t;

        apc = irq_data_get_irq_chip_data(d);
        irq = d->irq - apc->irq_base;

        t = __raw_readl(base + AR71XX_RESET_REG_PCI_INT_ENABLE);
        __raw_writel(t & ~(1 << irq), base + AR71XX_RESET_REG_PCI_INT_ENABLE);

        /* flush write */
        __raw_readl(base + AR71XX_RESET_REG_PCI_INT_ENABLE);
}

static struct irq_chip ar71xx_pci_irq_chip = {
        .name           = "AR71XX PCI",
        .irq_mask       = ar71xx_pci_irq_mask,
        .irq_unmask     = ar71xx_pci_irq_unmask,
        .irq_mask_ack   = ar71xx_pci_irq_mask,
};

static void ar71xx_pci_irq_init(struct ar71xx_pci_controller *apc)
{
        void __iomem *base = ath79_reset_base;
        int i;

        __raw_writel(0, base + AR71XX_RESET_REG_PCI_INT_ENABLE);
        __raw_writel(0, base + AR71XX_RESET_REG_PCI_INT_STATUS);

        BUILD_BUG_ON(ATH79_PCI_IRQ_COUNT < AR71XX_PCI_IRQ_COUNT);

        apc->irq_base = ATH79_PCI_IRQ_BASE;
        for (i = apc->irq_base;
             i < apc->irq_base + AR71XX_PCI_IRQ_COUNT; i++) {
                irq_set_chip_and_handler(i, &ar71xx_pci_irq_chip,
                                         handle_level_irq);
                irq_set_chip_data(i, apc);
        }

        irq_set_chained_handler_and_data(apc->irq, ar71xx_pci_irq_handler,
                                         apc);
}

static void ar71xx_pci_reset(void)
{
        ath79_device_reset_set(AR71XX_RESET_PCI_BUS | AR71XX_RESET_PCI_CORE);
        mdelay(100);

        ath79_device_reset_clear(AR71XX_RESET_PCI_BUS | AR71XX_RESET_PCI_CORE);
        mdelay(100);

        ath79_ddr_set_pci_windows();
        mdelay(100);
}

static int ar71xx_pci_probe(struct platform_device *pdev)
{
        struct ar71xx_pci_controller *apc;
        struct resource *res;
        u32 t;

        apc = devm_kzalloc(&pdev->dev, sizeof(struct ar71xx_pci_controller),
                           GFP_KERNEL);
        if (!apc)
                return -ENOMEM;

        apc->cfg_base = devm_platform_ioremap_resource_byname(pdev,
                                                              "cfg_base");
        if (IS_ERR(apc->cfg_base))
                return PTR_ERR(apc->cfg_base);

        apc->irq = platform_get_irq(pdev, 0);
        if (apc->irq < 0)
                return -EINVAL;

        res = platform_get_resource_byname(pdev, IORESOURCE_IO, "io_base");
        if (!res)
                return -EINVAL;

        apc->io_res.parent = res;
        apc->io_res.name = "PCI IO space";
        apc->io_res.start = res->start;
        apc->io_res.end = res->end;
        apc->io_res.flags = IORESOURCE_IO;

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem_base");
        if (!res)
                return -EINVAL;

        apc->mem_res.parent = res;
        apc->mem_res.name = "PCI memory space";
        apc->mem_res.start = res->start;
        apc->mem_res.end = res->end;
        apc->mem_res.flags = IORESOURCE_MEM;

        ar71xx_pci_reset();

        /* setup COMMAND register */
        t = PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER | PCI_COMMAND_INVALIDATE
          | PCI_COMMAND_PARITY | PCI_COMMAND_SERR | PCI_COMMAND_FAST_BACK;
        ar71xx_pci_local_write(apc, PCI_COMMAND, 4, t);

        /* clear bus errors */
        ar71xx_pci_check_error(apc, 1);

        ar71xx_pci_irq_init(apc);

        apc->pci_ctrl.pci_ops = &ar71xx_pci_ops;
        apc->pci_ctrl.mem_resource = &apc->mem_res;
        apc->pci_ctrl.io_resource = &apc->io_res;

        register_pci_controller(&apc->pci_ctrl);

        return 0;
}

static struct platform_driver ar71xx_pci_driver = {
        .probe = ar71xx_pci_probe,
        .driver = {
                .name = "ar71xx-pci",
        },
};

static int __init ar71xx_pci_init(void)
{
        return platform_driver_register(&ar71xx_pci_driver);
}

postcore_initcall(ar71xx_pci_init);