/*
 * Copyright 2012 Red Hat Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 */
#include "priv.h"

#include <subdev/pci.h>

#define NV_PBUS_IFR_FMT_FIXED0_SIGNATURE_VALUE 0x4947564E	/* "NVGI" */
#define NV_ROM_DIRECTORY_IDENTIFIER 0x44524652			/* "RFRD" */

struct priv {
	struct nvkm_device *device;
	u32 pci_rom_offset;
};

static u32
nvbios_prom_read(void *data, u32 offset, u32 length, struct nvkm_bios *bios)
{
	struct priv *priv = data;
	struct nvkm_device *device = priv->device;
	u32 i;

	/* Make sure we don't try to read past the end of data[] */
	if (offset + length > bios->size)
		return 0;

	/* Make sure the read falls within the 1MB PROM window */
	if (offset + priv->pci_rom_offset + length > 0x00100000)
		return 0;

	for (i = offset; i < offset + length; i += 4)
		*(u32 *)&bios->data[i] = nvkm_rd32(device, 0x300000 + priv->pci_rom_offset + i);
	return length;
}

static void
nvbios_prom_fini(void *data)
{
	struct priv *priv = data;
	struct nvkm_device *device = priv->device;

	nvkm_pci_rom_shadow(device->pci, true);

	kfree(data);
}

static void *
nvbios_prom_init(struct nvkm_bios *bios, const char *name)
{
	struct nvkm_device *device = bios->subdev.device;
	struct priv *priv;
	u32 fixed0;

	/* There is no PROM on NV4x iGPUs */
	if (device->card_type == NV_40 && device->chipset >= 0x4c)
		return ERR_PTR(-ENODEV);

	priv = kzalloc_obj(*priv);
	if (!priv)
		return ERR_PTR(-ENOMEM);

	/* Disable the PCI ROM shadow so that we can read PROM. */
	nvkm_pci_rom_shadow(device->pci, false);

	/*
	 * Check for an IFR header. If present, parse it to find the actual PCI ROM header.
	 *
	 * The IFR header is documented in Documentation/gpu/nova/core/vbios.rst
	 */
	fixed0 = nvkm_rd32(device, 0x300000);
	if (fixed0 == NV_PBUS_IFR_FMT_FIXED0_SIGNATURE_VALUE) {
		u32 fixed1 = nvkm_rd32(device, 0x300004);
		u8 version = (fixed1 >> 8) & 0xff;
		u32 fixed2, data_size, offset, signature;

		switch (version) {
		case 1:
		case 2:
			data_size = (fixed1 >> 16) & 0x7fff;
			priv->pci_rom_offset = nvkm_rd32(device, 0x300000 + data_size + 4);
			break;
		case 3:
			fixed2 = nvkm_rd32(device, 0x300008);
			data_size = fixed2 & 0x000fffff;

			/* ROM directory offset */
			offset = nvkm_rd32(device, 0x300000 + data_size) + 4096;

			signature = nvkm_rd32(device, 0x300000 + offset);
			if (signature != NV_ROM_DIRECTORY_IDENTIFIER) {
				nvkm_error(&bios->subdev, "could not find IFR ROM directory\n");
				goto fail;
			}

			priv->pci_rom_offset = nvkm_rd32(device, 0x300000 + offset + 8);

			break;
		default:
			nvkm_error(&bios->subdev, "unsupported IFR header version %u\n",
				   version);
			goto fail;
		}

		/* Double-check that the offset is valid */
		if (priv->pci_rom_offset >= 0x00100000) {
			nvkm_error(&bios->subdev,
				   "PCI ROM offset of 0x%x is too large\n", priv->pci_rom_offset);
			goto fail;
		}

		/* If there is an IFR header, there must also be a PCI ROM header. */
		signature = nvkm_rd32(device, 0x300000 + priv->pci_rom_offset) & 0xffff;
		if (signature != 0xaa55) {
			nvkm_error(&bios->subdev,
				   "could not find PCI ROM signature at offset 0x%x\n",
				   priv->pci_rom_offset);
			goto fail;
		}
	}

	priv->device = device;
	return priv;

fail:
	nvkm_pci_rom_shadow(device->pci, true);
	kfree(priv);
	return ERR_PTR(-ENODEV);
}

const struct nvbios_source
nvbios_prom = {
	.name = "PROM",
	.init = nvbios_prom_init,
	.fini = nvbios_prom_fini,
	.read = nvbios_prom_read,
	.rw = false,
};