// SPDX-License-Identifier: GPL-2.0
/*
 * Low-Level PCI Express Support for the SH7786
 *
 *  Copyright (C) 2009 - 2011  Paul Mundt
 */
#define pr_fmt(fmt) "PCI: " fmt

#include <linux/pci.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/async.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/sh_clk.h>
#include <linux/sh_intc.h>
#include <cpu/sh7786.h>
#include "pcie-sh7786.h"
#include <linux/sizes.h>

struct sh7786_pcie_port {
        struct pci_channel      *hose;
        struct clk              *fclk, phy_clk;
        unsigned int            index;
        int                     endpoint;
        int                     link;
};

static struct sh7786_pcie_port *sh7786_pcie_ports;
static unsigned int nr_ports;
static unsigned long dma_pfn_offset;

static struct sh7786_pcie_hwops {
        int (*core_init)(void);
        async_func_t port_init_hw;
} *sh7786_pcie_hwops;

static struct resource sh7786_pci0_resources[] = {
        {
                .name   = "PCIe0 MEM 0",
                .start  = 0xfd000000,
                .end    = 0xfd000000 + SZ_8M - 1,
                .flags  = IORESOURCE_MEM,
        }, {
                .name   = "PCIe0 MEM 1",
                .start  = 0xc0000000,
                .end    = 0xc0000000 + SZ_512M - 1,
                .flags  = IORESOURCE_MEM | IORESOURCE_MEM_32BIT,
        }, {
                .name   = "PCIe0 MEM 2",
                .start  = 0x10000000,
                .end    = 0x10000000 + SZ_64M - 1,
                .flags  = IORESOURCE_MEM,
        }, {
                .name   = "PCIe0 IO",
                .start  = 0xfe100000,
                .end    = 0xfe100000 + SZ_1M - 1,
                .flags  = IORESOURCE_IO,
        },
};

static struct resource sh7786_pci1_resources[] = {
        {
                .name   = "PCIe1 MEM 0",
                .start  = 0xfd800000,
                .end    = 0xfd800000 + SZ_8M - 1,
                .flags  = IORESOURCE_MEM,
        }, {
                .name   = "PCIe1 MEM 1",
                .start  = 0xa0000000,
                .end    = 0xa0000000 + SZ_512M - 1,
                .flags  = IORESOURCE_MEM | IORESOURCE_MEM_32BIT,
        }, {
                .name   = "PCIe1 MEM 2",
                .start  = 0x30000000,
                .end    = 0x30000000 + SZ_256M - 1,
                .flags  = IORESOURCE_MEM | IORESOURCE_MEM_32BIT,
        }, {
                .name   = "PCIe1 IO",
                .start  = 0xfe300000,
                .end    = 0xfe300000 + SZ_1M - 1,
                .flags  = IORESOURCE_IO,
        },
};

static struct resource sh7786_pci2_resources[] = {
        {
                .name   = "PCIe2 MEM 0",
                .start  = 0xfc800000,
                .end    = 0xfc800000 + SZ_4M - 1,
                .flags  = IORESOURCE_MEM,
        }, {
                .name   = "PCIe2 MEM 1",
                .start  = 0x80000000,
                .end    = 0x80000000 + SZ_512M - 1,
                .flags  = IORESOURCE_MEM | IORESOURCE_MEM_32BIT,
        }, {
                .name   = "PCIe2 MEM 2",
                .start  = 0x20000000,
                .end    = 0x20000000 + SZ_256M - 1,
                .flags  = IORESOURCE_MEM | IORESOURCE_MEM_32BIT,
        }, {
                .name   = "PCIe2 IO",
                .start  = 0xfcd00000,
                .end    = 0xfcd00000 + SZ_1M - 1,
                .flags  = IORESOURCE_IO,
        },
};

extern struct pci_ops sh7786_pci_ops;

#define DEFINE_CONTROLLER(start, idx)                                   \
{                                                                       \
        .pci_ops        = &sh7786_pci_ops,                              \
        .resources      = sh7786_pci##idx##_resources,                  \
        .nr_resources   = ARRAY_SIZE(sh7786_pci##idx##_resources),      \
        .reg_base       = start,                                        \
        .mem_offset     = 0,                                            \
        .io_offset      = 0,                                            \
}

static struct pci_channel sh7786_pci_channels[] = {
        DEFINE_CONTROLLER(0xfe000000, 0),
        DEFINE_CONTROLLER(0xfe200000, 1),
        DEFINE_CONTROLLER(0xfcc00000, 2),
};

static struct clk fixed_pciexclkp = {
        .rate = 100000000,      /* 100 MHz reference clock */
};

static void sh7786_pci_fixup(struct pci_dev *dev)
{
        /*
         * Prevent enumeration of root complex resources.
         */
        if (pci_is_root_bus(dev->bus) && dev->devfn == 0) {
                int i;

                for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
                        dev->resource[i].start  = 0;
                        dev->resource[i].end    = 0;
                        dev->resource[i].flags  = 0;
                }
        }
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_RENESAS, PCI_DEVICE_ID_RENESAS_SH7786,
                         sh7786_pci_fixup);

static int __init phy_wait_for_ack(struct pci_channel *chan)
{
        unsigned int timeout = 100;

        while (timeout--) {
                if (pci_read_reg(chan, SH4A_PCIEPHYADRR) & (1 << BITS_ACK))
                        return 0;

                udelay(100);
        }

        return -ETIMEDOUT;
}

static int __init pci_wait_for_irq(struct pci_channel *chan, unsigned int mask)
{
        unsigned int timeout = 100;

        while (timeout--) {
                if ((pci_read_reg(chan, SH4A_PCIEINTR) & mask) == mask)
                        return 0;

                udelay(100);
        }

        return -ETIMEDOUT;
}

static void __init phy_write_reg(struct pci_channel *chan, unsigned int addr,
                                 unsigned int lane, unsigned int data)
{
        unsigned long phyaddr;

        phyaddr = (1 << BITS_CMD) + ((lane & 0xf) << BITS_LANE) +
                        ((addr & 0xff) << BITS_ADR);

        /* Set write data */
        pci_write_reg(chan, data, SH4A_PCIEPHYDOUTR);
        pci_write_reg(chan, phyaddr, SH4A_PCIEPHYADRR);

        phy_wait_for_ack(chan);

        /* Clear command */
        pci_write_reg(chan, 0, SH4A_PCIEPHYDOUTR);
        pci_write_reg(chan, 0, SH4A_PCIEPHYADRR);

        phy_wait_for_ack(chan);
}

static int __init pcie_clk_init(struct sh7786_pcie_port *port)
{
        struct pci_channel *chan = port->hose;
        struct clk *clk;
        char fclk_name[16];
        int ret;

        /*
         * First register the fixed clock
         */
        ret = clk_register(&fixed_pciexclkp);
        if (unlikely(ret != 0))
                return ret;

        /*
         * Grab the port's function clock, which the PHY clock depends
         * on. clock lookups don't help us much at this point, since no
         * dev_id is available this early. Lame.
         */
        snprintf(fclk_name, sizeof(fclk_name), "pcie%d_fck", port->index);

        port->fclk = clk_get(NULL, fclk_name);
        if (IS_ERR(port->fclk)) {
                ret = PTR_ERR(port->fclk);
                goto err_fclk;
        }

        clk_enable(port->fclk);

        /*
         * And now, set up the PHY clock
         */
        clk = &port->phy_clk;

        memset(clk, 0, sizeof(struct clk));

        clk->parent = &fixed_pciexclkp;
        clk->enable_reg = (void __iomem *)(chan->reg_base + SH4A_PCIEPHYCTLR);
        clk->enable_bit = BITS_CKE;

        ret = sh_clk_mstp_register(clk, 1);
        if (unlikely(ret < 0))
                goto err_phy;

        return 0;

err_phy:
        clk_disable(port->fclk);
        clk_put(port->fclk);
err_fclk:
        clk_unregister(&fixed_pciexclkp);

        return ret;
}

static int __init phy_init(struct sh7786_pcie_port *port)
{
        struct pci_channel *chan = port->hose;
        unsigned int timeout = 100;

        clk_enable(&port->phy_clk);

        /* Initialize the phy */
        phy_write_reg(chan, 0x60, 0xf, 0x004b008b);
        phy_write_reg(chan, 0x61, 0xf, 0x00007b41);
        phy_write_reg(chan, 0x64, 0xf, 0x00ff4f00);
        phy_write_reg(chan, 0x65, 0xf, 0x09070907);
        phy_write_reg(chan, 0x66, 0xf, 0x00000010);
        phy_write_reg(chan, 0x74, 0xf, 0x0007001c);
        phy_write_reg(chan, 0x79, 0xf, 0x01fc000d);
        phy_write_reg(chan, 0xb0, 0xf, 0x00000610);

        /* Deassert Standby */
        phy_write_reg(chan, 0x67, 0x1, 0x00000400);

        /* Disable clock */
        clk_disable(&port->phy_clk);

        while (timeout--) {
                if (pci_read_reg(chan, SH4A_PCIEPHYSR))
                        return 0;

                udelay(100);
        }

        return -ETIMEDOUT;
}

static void __init pcie_reset(struct sh7786_pcie_port *port)
{
        struct pci_channel *chan = port->hose;

        pci_write_reg(chan, 1, SH4A_PCIESRSTR);
        pci_write_reg(chan, 0, SH4A_PCIETCTLR);
        pci_write_reg(chan, 0, SH4A_PCIESRSTR);
        pci_write_reg(chan, 0, SH4A_PCIETXVC0SR);
}

static int __init pcie_init(struct sh7786_pcie_port *port)
{
        struct pci_channel *chan = port->hose;
        unsigned int data;
        phys_addr_t memstart, memend;
        size_t memsize;
        int ret, i, win;

        /* Begin initialization */
        pcie_reset(port);

        /*
         * Initial header for port config space is type 1, set the device
         * class to match. Hardware takes care of propagating the IDSETR
         * settings, so there is no need to bother with a quirk.
         */
        pci_write_reg(chan, PCI_CLASS_BRIDGE_PCI << 16, SH4A_PCIEIDSETR1);

        /* Initialize default capabilities. */
        data = pci_read_reg(chan, SH4A_PCIEEXPCAP0);
        data &= ~(PCI_EXP_FLAGS_TYPE << 16);

        if (port->endpoint)
                data |= PCI_EXP_TYPE_ENDPOINT << 20;
        else
                data |= PCI_EXP_TYPE_ROOT_PORT << 20;

        data |= PCI_CAP_ID_EXP;
        pci_write_reg(chan, data, SH4A_PCIEEXPCAP0);

        /* Enable data link layer active state reporting */
        pci_write_reg(chan, PCI_EXP_LNKCAP_DLLLARC, SH4A_PCIEEXPCAP3);

        /* Enable extended sync and ASPM L0s support */
        data = pci_read_reg(chan, SH4A_PCIEEXPCAP4);
        data &= ~PCI_EXP_LNKCTL_ASPMC;
        data |= PCI_EXP_LNKCTL_ES | 1;
        pci_write_reg(chan, data, SH4A_PCIEEXPCAP4);

        /* Write out the physical slot number */
        data = pci_read_reg(chan, SH4A_PCIEEXPCAP5);
        data &= ~PCI_EXP_SLTCAP_PSN;
        data |= (port->index + 1) << 19;
        pci_write_reg(chan, data, SH4A_PCIEEXPCAP5);

        /* Set the completion timer timeout to the maximum 32ms. */
        data = pci_read_reg(chan, SH4A_PCIETLCTLR);
        data &= ~0x3f00;
        data |= 0x32 << 8;
        pci_write_reg(chan, data, SH4A_PCIETLCTLR);

        /*
         * Set fast training sequences to the maximum 255,
         * and enable MAC data scrambling.
         */
        data = pci_read_reg(chan, SH4A_PCIEMACCTLR);
        data &= ~PCIEMACCTLR_SCR_DIS;
        data |= (0xff << 16);
        pci_write_reg(chan, data, SH4A_PCIEMACCTLR);

        memstart = __pa(memory_start);
        memend   = __pa(memory_end);
        memsize = roundup_pow_of_two(memend - memstart);

        /*
         * The start address must be aligned on its size. So we round
         * it down, and then recalculate the size so that it covers
         * the entire memory.
         */
        memstart = ALIGN_DOWN(memstart, memsize);
        memsize = roundup_pow_of_two(memend - memstart);

        dma_pfn_offset = memstart >> PAGE_SHIFT;

        /*
         * If there's more than 512MB of memory, we need to roll over to
         * LAR1/LAMR1.
         */
        if (memsize > SZ_512M) {
                pci_write_reg(chan, memstart + SZ_512M, SH4A_PCIELAR1);
                pci_write_reg(chan, ((memsize - SZ_512M) - SZ_256) | 1,
                              SH4A_PCIELAMR1);
                memsize = SZ_512M;
        } else {
                /*
                 * Otherwise just zero it out and disable it.
                 */
                pci_write_reg(chan, 0, SH4A_PCIELAR1);
                pci_write_reg(chan, 0, SH4A_PCIELAMR1);
        }

        /*
         * LAR0/LAMR0 covers up to the first 512MB, which is enough to
         * cover all of lowmem on most platforms.
         */
        pci_write_reg(chan, memstart, SH4A_PCIELAR0);
        pci_write_reg(chan, (memsize - SZ_256) | 1, SH4A_PCIELAMR0);

        /* Finish initialization */
        data = pci_read_reg(chan, SH4A_PCIETCTLR);
        data |= 0x1;
        pci_write_reg(chan, data, SH4A_PCIETCTLR);

        /* Let things settle down a bit.. */
        mdelay(100);

        /* Enable DL_Active Interrupt generation */
        data = pci_read_reg(chan, SH4A_PCIEDLINTENR);
        data |= PCIEDLINTENR_DLL_ACT_ENABLE;
        pci_write_reg(chan, data, SH4A_PCIEDLINTENR);

        /* Disable MAC data scrambling. */
        data = pci_read_reg(chan, SH4A_PCIEMACCTLR);
        data |= PCIEMACCTLR_SCR_DIS | (0xff << 16);
        pci_write_reg(chan, data, SH4A_PCIEMACCTLR);

        /*
         * This will timeout if we don't have a link, but we permit the
         * port to register anyways in order to support hotplug on future
         * hardware.
         */
        ret = pci_wait_for_irq(chan, MASK_INT_TX_CTRL);

        data = pci_read_reg(chan, SH4A_PCIEPCICONF1);
        data &= ~(PCI_STATUS_DEVSEL_MASK << 16);
        data |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER |
                (PCI_STATUS_CAP_LIST | PCI_STATUS_DEVSEL_FAST) << 16;
        pci_write_reg(chan, data, SH4A_PCIEPCICONF1);

        pci_write_reg(chan, 0x80888000, SH4A_PCIETXVC0DCTLR);
        pci_write_reg(chan, 0x00222000, SH4A_PCIERXVC0DCTLR);

        wmb();

        if (ret == 0) {
                data = pci_read_reg(chan, SH4A_PCIEMACSR);
                printk(KERN_NOTICE "PCI: PCIe#%d x%d link detected\n",
                       port->index, (data >> 20) & 0x3f);
        } else
                printk(KERN_NOTICE "PCI: PCIe#%d link down\n",
                       port->index);

        for (i = win = 0; i < chan->nr_resources; i++) {
                struct resource *res = chan->resources + i;
                resource_size_t size;
                u32 mask;

                /*
                 * We can't use the 32-bit mode windows in legacy 29-bit
                 * mode, so just skip them entirely.
                 */
                if ((res->flags & IORESOURCE_MEM_32BIT) && __in_29bit_mode())
                        res->flags |= IORESOURCE_DISABLED;

                if (res->flags & IORESOURCE_DISABLED)
                        continue;

                pci_write_reg(chan, 0x00000000, SH4A_PCIEPTCTLR(win));

                /*
                 * The PAMR mask is calculated in units of 256kB, which
                 * keeps things pretty simple.
                 */
                size = resource_size(res);
                mask = (roundup_pow_of_two(size) / SZ_256K) - 1;
                pci_write_reg(chan, mask << 18, SH4A_PCIEPAMR(win));

                pci_write_reg(chan, upper_32_bits(res->start),
                              SH4A_PCIEPARH(win));
                pci_write_reg(chan, lower_32_bits(res->start),
                              SH4A_PCIEPARL(win));

                mask = MASK_PARE;
                if (res->flags & IORESOURCE_IO)
                        mask |= MASK_SPC;

                pci_write_reg(chan, mask, SH4A_PCIEPTCTLR(win));

                win++;
        }

        return 0;
}

int pcibios_map_platform_irq(const struct pci_dev *pdev, u8 slot, u8 pin)
{
        return evt2irq(0xae0);
}

void pcibios_bus_add_device(struct pci_dev *pdev)
{
        pdev->dev.dma_pfn_offset = dma_pfn_offset;
}

static int __init sh7786_pcie_core_init(void)
{
        /* Return the number of ports */
        return test_mode_pin(MODE_PIN12) ? 3 : 2;
}

static void __init sh7786_pcie_init_hw(void *data, async_cookie_t cookie)
{
        struct sh7786_pcie_port *port = data;
        int ret;

        /*
         * Check if we are configured in endpoint or root complex mode,
         * this is a fixed pin setting that applies to all PCIe ports.
         */
        port->endpoint = test_mode_pin(MODE_PIN11);

        /*
         * Setup clocks, needed both for PHY and PCIe registers.
         */
        ret = pcie_clk_init(port);
        if (unlikely(ret < 0)) {
                pr_err("clock initialization failed for port#%d\n",
                       port->index);
                return;
        }

        ret = phy_init(port);
        if (unlikely(ret < 0)) {
                pr_err("phy initialization failed for port#%d\n",
                       port->index);
                return;
        }

        ret = pcie_init(port);
        if (unlikely(ret < 0)) {
                pr_err("core initialization failed for port#%d\n",
                               port->index);
                return;
        }

        /* In the interest of preserving device ordering, synchronize */
        async_synchronize_cookie(cookie);

        register_pci_controller(port->hose);
}

static struct sh7786_pcie_hwops sh7786_65nm_pcie_hwops __initdata = {
        .core_init      = sh7786_pcie_core_init,
        .port_init_hw   = sh7786_pcie_init_hw,
};

static int __init sh7786_pcie_init(void)
{
        struct clk *platclk;
        u32 mm_sel;
        int i;

        printk(KERN_NOTICE "PCI: Starting initialization.\n");

        sh7786_pcie_hwops = &sh7786_65nm_pcie_hwops;

        nr_ports = sh7786_pcie_hwops->core_init();
        BUG_ON(nr_ports > ARRAY_SIZE(sh7786_pci_channels));

        if (unlikely(nr_ports == 0))
                return -ENODEV;

        sh7786_pcie_ports = kcalloc(nr_ports, sizeof(struct sh7786_pcie_port),
                                    GFP_KERNEL);
        if (unlikely(!sh7786_pcie_ports))
                return -ENOMEM;

        /*
         * Fetch any optional platform clock associated with this block.
         *
         * This is a rather nasty hack for boards with spec-mocking FPGAs
         * that have a secondary set of clocks outside of the on-chip
         * ones that need to be accounted for before there is any chance
         * of touching the existing MSTP bits or CPG clocks.
         */
        platclk = clk_get(NULL, "pcie_plat_clk");
        if (IS_ERR(platclk)) {
                /* Sane hardware should probably get a WARN_ON.. */
                platclk = NULL;
        }

        clk_enable(platclk);

        mm_sel = sh7786_mm_sel();

        /*
         * Depending on the MMSELR register value, the PCIe0 MEM 1
         * area may not be available. See Table 13.11 of the SH7786
         * datasheet.
         */
        if (mm_sel != 1 && mm_sel != 2 && mm_sel != 5 && mm_sel != 6)
                sh7786_pci0_resources[2].flags |= IORESOURCE_DISABLED;

        printk(KERN_NOTICE "PCI: probing %d ports.\n", nr_ports);

        for (i = 0; i < nr_ports; i++) {
                struct sh7786_pcie_port *port = sh7786_pcie_ports + i;

                port->index             = i;
                port->hose              = sh7786_pci_channels + i;
                port->hose->io_map_base = port->hose->resources[0].start;

                async_schedule(sh7786_pcie_hwops->port_init_hw, port);
        }

        async_synchronize_full();

        return 0;
}
arch_initcall(sh7786_pcie_init);