// SPDX-License-Identifier: MIT
/*
 * Copyright © 2024 Intel Corporation
 */

#include "i915_drv.h"
#include "i915_reg.h"

#include "intel_rom.h"
#include "intel_uncore.h"

#include <dev/isa/isareg.h>
#include <dev/isa/isavar.h>

#define VGA_BIOS_ADDR   0xc0000
#define VGA_BIOS_LEN    0x10000

struct intel_rom {
        /* for PCI ROM */
        struct pci_dev *pdev;
        void __iomem *oprom;

        /* for SPI */
        struct intel_uncore *uncore;
        loff_t offset;

        size_t size;

        u32 (*read32)(struct intel_rom *rom, loff_t offset);
        u16 (*read16)(struct intel_rom *rom, loff_t offset);
        void (*read_block)(struct intel_rom *rom, void *data, loff_t offset, size_t size);
        void (*free)(struct intel_rom *rom);
};

static u32 spi_read32(struct intel_rom *rom, loff_t offset)
{
        intel_uncore_write(rom->uncore, PRIMARY_SPI_ADDRESS,
                           rom->offset + offset);

        return intel_uncore_read(rom->uncore, PRIMARY_SPI_TRIGGER);
}

static u16 spi_read16(struct intel_rom *rom, loff_t offset)
{
        return spi_read32(rom, offset) & 0xffff;
}

struct intel_rom *intel_rom_spi(struct drm_i915_private *i915)
{
        struct intel_rom *rom;
        u32 static_region;

        rom = kzalloc(sizeof(*rom), GFP_KERNEL);
        if (!rom)
                return NULL;

        rom->uncore = &i915->uncore;

        static_region = intel_uncore_read(rom->uncore, SPI_STATIC_REGIONS);
        static_region &= OPTIONROM_SPI_REGIONID_MASK;
        intel_uncore_write(rom->uncore, PRIMARY_SPI_REGIONID, static_region);

        rom->offset = intel_uncore_read(rom->uncore, OROM_OFFSET) & OROM_OFFSET_MASK;

        rom->size = 0x200000;

        rom->read32 = spi_read32;
        rom->read16 = spi_read16;

        return rom;
}

static u32 pci_read32(struct intel_rom *rom, loff_t offset)
{
        return ioread32(rom->oprom + offset);
}

static u16 pci_read16(struct intel_rom *rom, loff_t offset)
{
        return ioread16(rom->oprom + offset);
}

static void pci_read_block(struct intel_rom *rom, void *data,
                           loff_t offset, size_t size)
{
        memcpy_fromio(data, rom->oprom + offset, size);
}

static void pci_free(struct intel_rom *rom)
{
#ifdef __linux__
        pci_unmap_rom(rom->pdev, rom->oprom);
#endif
}

struct intel_rom *intel_rom_pci(struct drm_i915_private *i915)
{
        struct intel_rom *rom;

        rom = kzalloc(sizeof(*rom), GFP_KERNEL);
        if (!rom)
                return NULL;

        rom->pdev = i915->drm.pdev;

#ifdef __linux__
        rom->oprom = pci_map_rom(rom->pdev, &rom->size);
#else
        rom->oprom = (u8 *)ISA_HOLE_VADDR(VGA_BIOS_ADDR);
        rom->size = VGA_BIOS_LEN;
#endif
        if (!rom->oprom) {
                kfree(rom);
                return NULL;
        }

        rom->read32 = pci_read32;
        rom->read16 = pci_read16;
        rom->read_block = pci_read_block;
        rom->free = pci_free;

        return rom;
}

u32 intel_rom_read32(struct intel_rom *rom, loff_t offset)
{
        return rom->read32(rom, offset);
}

u16 intel_rom_read16(struct intel_rom *rom, loff_t offset)
{
        return rom->read16(rom, offset);
}

void intel_rom_read_block(struct intel_rom *rom, void *data,
                          loff_t offset, size_t size)
{
        u32 *ptr = data;
        loff_t index;

        if (rom->read_block) {
                rom->read_block(rom, data, offset, size);
                return;
        }

        for (index = 0; index < size; index += 4)
                *ptr++ = rom->read32(rom, offset + index);
}

loff_t intel_rom_find(struct intel_rom *rom, u32 needle)
{
        loff_t offset;

        for (offset = 0; offset < rom->size; offset += 4) {
                if (rom->read32(rom, offset) == needle)
                        return offset;
        }

        return -ENOENT;
}

size_t intel_rom_size(struct intel_rom *rom)
{
        return rom->size;
}

void intel_rom_free(struct intel_rom *rom)
{
        if (rom && rom->free)
                rom->free(rom);

        kfree(rom);
}