root/arch/mips/pci/pci-rt3883.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Ralink RT3662/RT3883 SoC PCI support
 *
 *  Copyright (C) 2011-2013 Gabor Juhos <juhosg@openwrt.org>
 *
 *  Parts of this file are based on Ralink's 2.6.21 BSP
 */

#include <linux/types.h>
#include <linux/pci.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/platform_device.h>

#include <asm/mach-ralink/rt3883.h>
#include <asm/mach-ralink/ralink_regs.h>

#define RT3883_MEMORY_BASE              0x00000000
#define RT3883_MEMORY_SIZE              0x02000000

#define RT3883_PCI_REG_PCICFG           0x00
#define   RT3883_PCICFG_P2P_BR_DEVNUM_M 0xf
#define   RT3883_PCICFG_P2P_BR_DEVNUM_S 16
#define   RT3883_PCICFG_PCIRST          BIT(1)
#define RT3883_PCI_REG_PCIRAW           0x04
#define RT3883_PCI_REG_PCIINT           0x08
#define RT3883_PCI_REG_PCIENA           0x0c

#define RT3883_PCI_REG_CFGADDR          0x20
#define RT3883_PCI_REG_CFGDATA          0x24
#define RT3883_PCI_REG_MEMBASE          0x28
#define RT3883_PCI_REG_IOBASE           0x2c
#define RT3883_PCI_REG_ARBCTL           0x80

#define RT3883_PCI_REG_BASE(_x)         (0x1000 + (_x) * 0x1000)
#define RT3883_PCI_REG_BAR0SETUP(_x)    (RT3883_PCI_REG_BASE((_x)) + 0x10)
#define RT3883_PCI_REG_IMBASEBAR0(_x)   (RT3883_PCI_REG_BASE((_x)) + 0x18)
#define RT3883_PCI_REG_ID(_x)           (RT3883_PCI_REG_BASE((_x)) + 0x30)
#define RT3883_PCI_REG_CLASS(_x)        (RT3883_PCI_REG_BASE((_x)) + 0x34)
#define RT3883_PCI_REG_SUBID(_x)        (RT3883_PCI_REG_BASE((_x)) + 0x38)
#define RT3883_PCI_REG_STATUS(_x)       (RT3883_PCI_REG_BASE((_x)) + 0x50)

#define RT3883_PCI_MODE_NONE    0
#define RT3883_PCI_MODE_PCI     BIT(0)
#define RT3883_PCI_MODE_PCIE    BIT(1)
#define RT3883_PCI_MODE_BOTH    (RT3883_PCI_MODE_PCI | RT3883_PCI_MODE_PCIE)

#define RT3883_PCI_IRQ_COUNT    32

#define RT3883_P2P_BR_DEVNUM    1

struct rt3883_pci_controller {
        void __iomem *base;

        struct device_node *intc_of_node;
        struct irq_domain *irq_domain;

        struct pci_controller pci_controller;
        struct resource io_res;
        struct resource mem_res;

        bool pcie_ready;
};

static inline struct rt3883_pci_controller *
pci_bus_to_rt3883_controller(struct pci_bus *bus)
{
        struct pci_controller *hose;

        hose = (struct pci_controller *) bus->sysdata;
        return container_of(hose, struct rt3883_pci_controller, pci_controller);
}

static inline u32 rt3883_pci_r32(struct rt3883_pci_controller *rpc,
                                 unsigned reg)
{
        return ioread32(rpc->base + reg);
}

static inline void rt3883_pci_w32(struct rt3883_pci_controller *rpc,
                                  u32 val, unsigned reg)
{
        iowrite32(val, rpc->base + reg);
}

static inline u32 rt3883_pci_get_cfgaddr(unsigned int bus, unsigned int slot,
                                         unsigned int func, unsigned int where)
{
        return (bus << 16) | (slot << 11) | (func << 8) | (where & 0xfc) |
               0x80000000;
}

static u32 rt3883_pci_read_cfg32(struct rt3883_pci_controller *rpc,
                               unsigned bus, unsigned slot,
                               unsigned func, unsigned reg)
{
        u32 address;

        address = rt3883_pci_get_cfgaddr(bus, slot, func, reg);

        rt3883_pci_w32(rpc, address, RT3883_PCI_REG_CFGADDR);

        return rt3883_pci_r32(rpc, RT3883_PCI_REG_CFGDATA);
}

static void rt3883_pci_write_cfg32(struct rt3883_pci_controller *rpc,
                                 unsigned bus, unsigned slot,
                                 unsigned func, unsigned reg, u32 val)
{
        u32 address;

        address = rt3883_pci_get_cfgaddr(bus, slot, func, reg);

        rt3883_pci_w32(rpc, address, RT3883_PCI_REG_CFGADDR);
        rt3883_pci_w32(rpc, val, RT3883_PCI_REG_CFGDATA);
}

static void rt3883_pci_irq_handler(struct irq_desc *desc)
{
        struct rt3883_pci_controller *rpc;
        u32 pending;

        rpc = irq_desc_get_handler_data(desc);

        pending = rt3883_pci_r32(rpc, RT3883_PCI_REG_PCIINT) &
                  rt3883_pci_r32(rpc, RT3883_PCI_REG_PCIENA);

        if (!pending) {
                spurious_interrupt();
                return;
        }

        while (pending) {
                unsigned bit = __ffs(pending);

                generic_handle_domain_irq(rpc->irq_domain, bit);

                pending &= ~BIT(bit);
        }
}

static void rt3883_pci_irq_unmask(struct irq_data *d)
{
        struct rt3883_pci_controller *rpc;
        u32 t;

        rpc = irq_data_get_irq_chip_data(d);

        t = rt3883_pci_r32(rpc, RT3883_PCI_REG_PCIENA);
        rt3883_pci_w32(rpc, t | BIT(d->hwirq), RT3883_PCI_REG_PCIENA);
        /* flush write */
        rt3883_pci_r32(rpc, RT3883_PCI_REG_PCIENA);
}

static void rt3883_pci_irq_mask(struct irq_data *d)
{
        struct rt3883_pci_controller *rpc;
        u32 t;

        rpc = irq_data_get_irq_chip_data(d);

        t = rt3883_pci_r32(rpc, RT3883_PCI_REG_PCIENA);
        rt3883_pci_w32(rpc, t & ~BIT(d->hwirq), RT3883_PCI_REG_PCIENA);
        /* flush write */
        rt3883_pci_r32(rpc, RT3883_PCI_REG_PCIENA);
}

static struct irq_chip rt3883_pci_irq_chip = {
        .name           = "RT3883 PCI",
        .irq_mask       = rt3883_pci_irq_mask,
        .irq_unmask     = rt3883_pci_irq_unmask,
        .irq_mask_ack   = rt3883_pci_irq_mask,
};

static int rt3883_pci_irq_map(struct irq_domain *d, unsigned int irq,
                              irq_hw_number_t hw)
{
        irq_set_chip_and_handler(irq, &rt3883_pci_irq_chip, handle_level_irq);
        irq_set_chip_data(irq, d->host_data);

        return 0;
}

static const struct irq_domain_ops rt3883_pci_irq_domain_ops = {
        .map = rt3883_pci_irq_map,
        .xlate = irq_domain_xlate_onecell,
};

static int rt3883_pci_irq_init(struct device *dev,
                               struct rt3883_pci_controller *rpc)
{
        int irq;

        irq = irq_of_parse_and_map(rpc->intc_of_node, 0);
        if (irq == 0) {
                dev_err(dev, "%pOF has no IRQ", rpc->intc_of_node);
                return -EINVAL;
        }

        /* disable all interrupts */
        rt3883_pci_w32(rpc, 0, RT3883_PCI_REG_PCIENA);

        rpc->irq_domain =
                irq_domain_create_linear(of_fwnode_handle(rpc->intc_of_node),
                                         RT3883_PCI_IRQ_COUNT,
                                         &rt3883_pci_irq_domain_ops,
                                         rpc);
        if (!rpc->irq_domain) {
                dev_err(dev, "unable to add IRQ domain\n");
                return -ENODEV;
        }

        irq_set_chained_handler_and_data(irq, rt3883_pci_irq_handler, rpc);

        return 0;
}

static int rt3883_pci_config_read(struct pci_bus *bus, unsigned int devfn,
                                  int where, int size, u32 *val)
{
        struct rt3883_pci_controller *rpc;
        u32 address;
        u32 data;

        rpc = pci_bus_to_rt3883_controller(bus);

        if (!rpc->pcie_ready && bus->number == 1)
                return PCIBIOS_DEVICE_NOT_FOUND;

        address = rt3883_pci_get_cfgaddr(bus->number, PCI_SLOT(devfn),
                                         PCI_FUNC(devfn), where);

        rt3883_pci_w32(rpc, address, RT3883_PCI_REG_CFGADDR);
        data = rt3883_pci_r32(rpc, RT3883_PCI_REG_CFGDATA);

        switch (size) {
        case 1:
                *val = (data >> ((where & 3) << 3)) & 0xff;
                break;
        case 2:
                *val = (data >> ((where & 3) << 3)) & 0xffff;
                break;
        case 4:
                *val = data;
                break;
        }

        return PCIBIOS_SUCCESSFUL;
}

static int rt3883_pci_config_write(struct pci_bus *bus, unsigned int devfn,
                                   int where, int size, u32 val)
{
        struct rt3883_pci_controller *rpc;
        u32 address;
        u32 data;

        rpc = pci_bus_to_rt3883_controller(bus);

        if (!rpc->pcie_ready && bus->number == 1)
                return PCIBIOS_DEVICE_NOT_FOUND;

        address = rt3883_pci_get_cfgaddr(bus->number, PCI_SLOT(devfn),
                                         PCI_FUNC(devfn), where);

        rt3883_pci_w32(rpc, address, RT3883_PCI_REG_CFGADDR);
        data = rt3883_pci_r32(rpc, RT3883_PCI_REG_CFGDATA);

        switch (size) {
        case 1:
                data = (data & ~(0xff << ((where & 3) << 3))) |
                       (val << ((where & 3) << 3));
                break;
        case 2:
                data = (data & ~(0xffff << ((where & 3) << 3))) |
                       (val << ((where & 3) << 3));
                break;
        case 4:
                data = val;
                break;
        }

        rt3883_pci_w32(rpc, data, RT3883_PCI_REG_CFGDATA);

        return PCIBIOS_SUCCESSFUL;
}

static struct pci_ops rt3883_pci_ops = {
        .read   = rt3883_pci_config_read,
        .write  = rt3883_pci_config_write,
};

static void rt3883_pci_preinit(struct rt3883_pci_controller *rpc, unsigned mode)
{
        u32 syscfg1;
        u32 rstctrl;
        u32 clkcfg1;
        u32 t;

        rstctrl = rt_sysc_r32(RT3883_SYSC_REG_RSTCTRL);
        syscfg1 = rt_sysc_r32(RT3883_SYSC_REG_SYSCFG1);
        clkcfg1 = rt_sysc_r32(RT3883_SYSC_REG_CLKCFG1);

        if (mode & RT3883_PCI_MODE_PCIE) {
                rstctrl |= RT3883_RSTCTRL_PCIE;
                rt_sysc_w32(rstctrl, RT3883_SYSC_REG_RSTCTRL);

                /* setup PCI PAD drive mode */
                syscfg1 &= ~(0x30);
                syscfg1 |= (2 << 4);
                rt_sysc_w32(syscfg1, RT3883_SYSC_REG_SYSCFG1);

                t = rt_sysc_r32(RT3883_SYSC_REG_PCIE_CLK_GEN0);
                t &= ~BIT(31);
                rt_sysc_w32(t, RT3883_SYSC_REG_PCIE_CLK_GEN0);

                t = rt_sysc_r32(RT3883_SYSC_REG_PCIE_CLK_GEN1);
                t &= 0x80ffffff;
                rt_sysc_w32(t, RT3883_SYSC_REG_PCIE_CLK_GEN1);

                t = rt_sysc_r32(RT3883_SYSC_REG_PCIE_CLK_GEN1);
                t |= 0xa << 24;
                rt_sysc_w32(t, RT3883_SYSC_REG_PCIE_CLK_GEN1);

                t = rt_sysc_r32(RT3883_SYSC_REG_PCIE_CLK_GEN0);
                t |= BIT(31);
                rt_sysc_w32(t, RT3883_SYSC_REG_PCIE_CLK_GEN0);

                msleep(50);

                rstctrl &= ~RT3883_RSTCTRL_PCIE;
                rt_sysc_w32(rstctrl, RT3883_SYSC_REG_RSTCTRL);
        }

        syscfg1 |= (RT3883_SYSCFG1_PCIE_RC_MODE | RT3883_SYSCFG1_PCI_HOST_MODE);

        clkcfg1 &= ~(RT3883_CLKCFG1_PCI_CLK_EN | RT3883_CLKCFG1_PCIE_CLK_EN);

        if (mode & RT3883_PCI_MODE_PCI) {
                clkcfg1 |= RT3883_CLKCFG1_PCI_CLK_EN;
                rstctrl &= ~RT3883_RSTCTRL_PCI;
        }

        if (mode & RT3883_PCI_MODE_PCIE) {
                clkcfg1 |= RT3883_CLKCFG1_PCIE_CLK_EN;
                rstctrl &= ~RT3883_RSTCTRL_PCIE;
        }

        rt_sysc_w32(syscfg1, RT3883_SYSC_REG_SYSCFG1);
        rt_sysc_w32(rstctrl, RT3883_SYSC_REG_RSTCTRL);
        rt_sysc_w32(clkcfg1, RT3883_SYSC_REG_CLKCFG1);

        msleep(500);

        /*
         * setup the device number of the P2P bridge
         * and de-assert the reset line
         */
        t = (RT3883_P2P_BR_DEVNUM << RT3883_PCICFG_P2P_BR_DEVNUM_S);
        rt3883_pci_w32(rpc, t, RT3883_PCI_REG_PCICFG);

        /* flush write */
        rt3883_pci_r32(rpc, RT3883_PCI_REG_PCICFG);
        msleep(500);

        if (mode & RT3883_PCI_MODE_PCIE) {
                msleep(500);

                t = rt3883_pci_r32(rpc, RT3883_PCI_REG_STATUS(1));

                rpc->pcie_ready = t & BIT(0);

                if (!rpc->pcie_ready) {
                        /* reset the PCIe block */
                        t = rt_sysc_r32(RT3883_SYSC_REG_RSTCTRL);
                        t |= RT3883_RSTCTRL_PCIE;
                        rt_sysc_w32(t, RT3883_SYSC_REG_RSTCTRL);
                        t &= ~RT3883_RSTCTRL_PCIE;
                        rt_sysc_w32(t, RT3883_SYSC_REG_RSTCTRL);

                        /* turn off PCIe clock */
                        t = rt_sysc_r32(RT3883_SYSC_REG_CLKCFG1);
                        t &= ~RT3883_CLKCFG1_PCIE_CLK_EN;
                        rt_sysc_w32(t, RT3883_SYSC_REG_CLKCFG1);

                        t = rt_sysc_r32(RT3883_SYSC_REG_PCIE_CLK_GEN0);
                        t &= ~0xf000c080;
                        rt_sysc_w32(t, RT3883_SYSC_REG_PCIE_CLK_GEN0);
                }
        }

        /* enable PCI arbiter */
        rt3883_pci_w32(rpc, 0x79, RT3883_PCI_REG_ARBCTL);
}

static int rt3883_pci_probe(struct platform_device *pdev)
{
        struct rt3883_pci_controller *rpc;
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct device_node *child;
        u32 val;
        int err;
        int mode;

        rpc = devm_kzalloc(dev, sizeof(*rpc), GFP_KERNEL);
        if (!rpc)
                return -ENOMEM;

        rpc->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(rpc->base))
                return PTR_ERR(rpc->base);

        /* find the interrupt controller child node */
        for_each_child_of_node(np, child) {
                if (of_property_read_bool(child, "interrupt-controller")) {
                        rpc->intc_of_node = child;
                        break;
                }
        }

        if (!rpc->intc_of_node) {
                dev_err(dev, "%pOF has no %s child node",
                        np, "interrupt controller");
                return -EINVAL;
        }

        /* find the PCI host bridge child node */
        for_each_child_of_node(np, child) {
                if (of_node_is_type(child, "pci")) {
                        rpc->pci_controller.of_node = child;
                        break;
                }
        }

        if (!rpc->pci_controller.of_node) {
                dev_err(dev, "%pOF has no %s child node",
                        np, "PCI host bridge");
                err = -EINVAL;
                goto err_put_intc_node;
        }

        mode = RT3883_PCI_MODE_NONE;
        for_each_available_child_of_node(rpc->pci_controller.of_node, child) {
                int devfn;

                if (!of_node_is_type(child, "pci"))
                        continue;

                devfn = of_pci_get_devfn(child);
                if (devfn < 0)
                        continue;

                switch (PCI_SLOT(devfn)) {
                case 1:
                        mode |= RT3883_PCI_MODE_PCIE;
                        break;

                case 17:
                case 18:
                        mode |= RT3883_PCI_MODE_PCI;
                        break;
                }
        }

        if (mode == RT3883_PCI_MODE_NONE) {
                dev_err(dev, "unable to determine PCI mode\n");
                err = -EINVAL;
                goto err_put_hb_node;
        }

        dev_info(dev, "mode:%s%s\n",
                 (mode & RT3883_PCI_MODE_PCI) ? " PCI" : "",
                 (mode & RT3883_PCI_MODE_PCIE) ? " PCIe" : "");

        rt3883_pci_preinit(rpc, mode);

        rpc->pci_controller.pci_ops = &rt3883_pci_ops;
        rpc->pci_controller.io_resource = &rpc->io_res;
        rpc->pci_controller.mem_resource = &rpc->mem_res;

        /* Load PCI I/O and memory resources from DT */
        pci_load_of_ranges(&rpc->pci_controller,
                           rpc->pci_controller.of_node);

        rt3883_pci_w32(rpc, rpc->mem_res.start, RT3883_PCI_REG_MEMBASE);
        rt3883_pci_w32(rpc, rpc->io_res.start, RT3883_PCI_REG_IOBASE);

        ioport_resource.start = rpc->io_res.start;
        ioport_resource.end = rpc->io_res.end;

        /* PCI */
        rt3883_pci_w32(rpc, 0x03ff0000, RT3883_PCI_REG_BAR0SETUP(0));
        rt3883_pci_w32(rpc, RT3883_MEMORY_BASE, RT3883_PCI_REG_IMBASEBAR0(0));
        rt3883_pci_w32(rpc, 0x08021814, RT3883_PCI_REG_ID(0));
        rt3883_pci_w32(rpc, 0x00800001, RT3883_PCI_REG_CLASS(0));
        rt3883_pci_w32(rpc, 0x28801814, RT3883_PCI_REG_SUBID(0));

        /* PCIe */
        rt3883_pci_w32(rpc, 0x03ff0000, RT3883_PCI_REG_BAR0SETUP(1));
        rt3883_pci_w32(rpc, RT3883_MEMORY_BASE, RT3883_PCI_REG_IMBASEBAR0(1));
        rt3883_pci_w32(rpc, 0x08021814, RT3883_PCI_REG_ID(1));
        rt3883_pci_w32(rpc, 0x06040001, RT3883_PCI_REG_CLASS(1));
        rt3883_pci_w32(rpc, 0x28801814, RT3883_PCI_REG_SUBID(1));

        err = rt3883_pci_irq_init(dev, rpc);
        if (err)
                goto err_put_hb_node;

        /* PCIe */
        val = rt3883_pci_read_cfg32(rpc, 0, 0x01, 0, PCI_COMMAND);
        val |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER;
        rt3883_pci_write_cfg32(rpc, 0, 0x01, 0, PCI_COMMAND, val);

        /* PCI */
        val = rt3883_pci_read_cfg32(rpc, 0, 0x00, 0, PCI_COMMAND);
        val |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER;
        rt3883_pci_write_cfg32(rpc, 0, 0x00, 0, PCI_COMMAND, val);

        if (mode == RT3883_PCI_MODE_PCIE) {
                rt3883_pci_w32(rpc, 0x03ff0001, RT3883_PCI_REG_BAR0SETUP(0));
                rt3883_pci_w32(rpc, 0x03ff0001, RT3883_PCI_REG_BAR0SETUP(1));

                rt3883_pci_write_cfg32(rpc, 0, RT3883_P2P_BR_DEVNUM, 0,
                                       PCI_BASE_ADDRESS_0,
                                       RT3883_MEMORY_BASE);
                /* flush write */
                rt3883_pci_read_cfg32(rpc, 0, RT3883_P2P_BR_DEVNUM, 0,
                                      PCI_BASE_ADDRESS_0);
        } else {
                rt3883_pci_write_cfg32(rpc, 0, RT3883_P2P_BR_DEVNUM, 0,
                                       PCI_IO_BASE, 0x00000101);
        }

        register_pci_controller(&rpc->pci_controller);

        return 0;

err_put_hb_node:
        of_node_put(rpc->pci_controller.of_node);
err_put_intc_node:
        of_node_put(rpc->intc_of_node);
        return err;
}

int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
{
        return of_irq_parse_and_map_pci(dev, slot, pin);
}

int pcibios_plat_dev_init(struct pci_dev *dev)
{
        return 0;
}

static const struct of_device_id rt3883_pci_ids[] = {
        { .compatible = "ralink,rt3883-pci" },
        {},
};

static struct platform_driver rt3883_pci_driver = {
        .probe = rt3883_pci_probe,
        .driver = {
                .name = "rt3883-pci",
                .of_match_table = of_match_ptr(rt3883_pci_ids),
        },
};

static int __init rt3883_pci_init(void)
{
        return platform_driver_register(&rt3883_pci_driver);
}

postcore_initcall(rt3883_pci_init);