drm/i915/bios: Extract soc/intel_rom.c

Abstract away the nuts and bolts of the SPI vs. PCI ROM
stuff, and hide it all in soc/intel_rom.c so that the
VBT code doesn't have to care about this stuff.

This leaves intel_bios.c with a single codepath that
can focus on the details related to the VBT layout.

This should have no functional changes.

v2: Rebase due to vbt_signature changes
    Drop unnecessary cast (Jani)

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240923152453.11230-7-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/Makefile

@@ -51,7 +51,8 @@ i915-y += \
 i915-y += \
 	soc/intel_dram.o \
 	soc/intel_gmch.o \
-	soc/intel_pch.o
+	soc/intel_pch.o \
+	soc/intel_rom.o
 
 # core library code
 i915-y += \

drivers/gpu/drm/i915/display/intel_bios.c

@@ -33,12 +33,12 @@
 #include <drm/drm_edid.h>
 #include <drm/drm_fixed.h>
 
+#include "soc/intel_rom.h"
+
 #include "i915_drv.h"
-#include "i915_reg.h"
 #include "intel_display.h"
 #include "intel_display_types.h"
 #include "intel_gmbus.h"
-#include "intel_uncore.h"
 
 #define _INTEL_BIOS_PRIVATE
 #include "intel_vbt_defs.h"
@@ -3056,152 +3056,59 @@ static struct vbt_header *firmware_get_vbt(struct intel_display *display,
 	return vbt;
 }
 
-static u32 intel_spi_read32(struct intel_uncore *uncore, u32 offset)
-{
-	intel_uncore_write(uncore, PRIMARY_SPI_ADDRESS, offset);
-
-	return intel_uncore_read(uncore, PRIMARY_SPI_TRIGGER);
-}
-
-static u16 intel_spi_read16(struct intel_uncore *uncore, u32 offset)
-{
-	return intel_spi_read32(uncore, offset) & 0xffff;
-}
-
-static struct vbt_header *spi_oprom_get_vbt(struct intel_display *display,
-					    size_t *size)
-{
-	struct drm_i915_private *i915 = to_i915(display->drm);
-	u32 count, data, found, store = 0;
-	u32 static_region, oprom_offset;
-	u32 oprom_size = 0x200000;
-	u16 vbt_size;
-	u32 *vbt;
-
-	static_region = intel_uncore_read(&i915->uncore, SPI_STATIC_REGIONS);
-	static_region &= OPTIONROM_SPI_REGIONID_MASK;
-	intel_uncore_write(&i915->uncore, PRIMARY_SPI_REGIONID, static_region);
-
-	oprom_offset = intel_uncore_read(&i915->uncore, OROM_OFFSET);
-	oprom_offset &= OROM_OFFSET_MASK;
-
-	BUILD_BUG_ON(vbt_signature_len != sizeof(vbt_signature) - 1);
-	BUILD_BUG_ON(vbt_signature_len != sizeof(u32));
-
-	for (count = 0; count < oprom_size; count += 4) {
-		data = intel_spi_read32(&i915->uncore, oprom_offset + count);
-		if (data == *((const u32 *)vbt_signature)) {
-			found = oprom_offset + count;
-			break;
-		}
-	}
-
-	if (count >= oprom_size)
-		goto err_not_found;
-
-	if (sizeof(struct vbt_header) > oprom_size - count) {
-		drm_dbg_kms(display->drm, "VBT header incomplete\n");
-		goto err_not_found;
-	}
-
-	/* Get VBT size and allocate space for the VBT */
-	vbt_size = intel_spi_read16(&i915->uncore,
-				    found + offsetof(struct vbt_header, vbt_size));
-
-	if (vbt_size > oprom_size - count) {
-		drm_dbg_kms(display->drm,
-			    "VBT incomplete (vbt_size overflows)\n");
-		goto err_not_found;
-	}
-
-	vbt = kzalloc(round_up(vbt_size, 4), GFP_KERNEL);
-	if (!vbt)
-		goto err_not_found;
-
-	for (count = 0; count < vbt_size; count += 4)
-		*(vbt + store++) = intel_spi_read32(&i915->uncore, found + count);
-
-	if (!intel_bios_is_valid_vbt(display, vbt, vbt_size))
-		goto err_free_vbt;
-
-	drm_dbg_kms(display->drm, "Found valid VBT in SPI flash\n");
-
-	if (size)
-		*size = vbt_size;
-
-	return (struct vbt_header *)vbt;
-
-err_free_vbt:
-	kfree(vbt);
-err_not_found:
-	return NULL;
-}
-
 static struct vbt_header *oprom_get_vbt(struct intel_display *display,
-					size_t *sizep)
+					struct intel_rom *rom,
+					size_t *size, const char *type)
 {
-	struct pci_dev *pdev = to_pci_dev(display->drm->dev);
-	void __iomem *p = NULL, *oprom;
 	struct vbt_header *vbt;
-	u16 vbt_size;
-	size_t i, size;
+	size_t vbt_size;
+	loff_t offset;
 
-	oprom = pci_map_rom(pdev, &size);
-	if (!oprom)
+	if (!rom)
 		return NULL;
 
 	BUILD_BUG_ON(vbt_signature_len != sizeof(vbt_signature) - 1);
 	BUILD_BUG_ON(vbt_signature_len != sizeof(u32));
 
-	/* Scour memory looking for the VBT signature. */
-	for (i = 0; i + 4 < size; i += 4) {
-		if (ioread32(oprom + i) != *((const u32 *)vbt_signature))
-			continue;
+	offset = intel_rom_find(rom, *(const u32 *)vbt_signature);
+	if (offset < 0)
+		goto err_free_rom;
 
-		p = oprom + i;
-		size -= i;
-		break;
-	}
-
-	if (!p)
-		goto err_unmap_oprom;
-
-	if (sizeof(struct vbt_header) > size) {
+	if (sizeof(struct vbt_header) > intel_rom_size(rom) - offset) {
 		drm_dbg_kms(display->drm, "VBT header incomplete\n");
-		goto err_unmap_oprom;
+		goto err_free_rom;
 	}
 
-	vbt_size = ioread16(p + offsetof(struct vbt_header, vbt_size));
-	if (vbt_size > size) {
-		drm_dbg_kms(display->drm,
-			    "VBT incomplete (vbt_size overflows)\n");
-		goto err_unmap_oprom;
+	BUILD_BUG_ON(sizeof(vbt->vbt_size) != sizeof(u16));
+
+	vbt_size = intel_rom_read16(rom, offset + offsetof(struct vbt_header, vbt_size));
+	if (vbt_size > intel_rom_size(rom) - offset) {
+		drm_dbg_kms(display->drm, "VBT incomplete (vbt_size overflows)\n");
+		goto err_free_rom;
 	}
 
-	/* The rest will be validated by intel_bios_is_valid_vbt() */
-	vbt = kmalloc(round_up(vbt_size, 4), GFP_KERNEL);
+	vbt = kzalloc(round_up(vbt_size, 4), GFP_KERNEL);
 	if (!vbt)
-		goto err_unmap_oprom;
+		goto err_free_rom;
 
-	memcpy_fromio(vbt, p, vbt_size);
+	intel_rom_read_block(rom, vbt, offset, vbt_size);
 
 	if (!intel_bios_is_valid_vbt(display, vbt, vbt_size))
 		goto err_free_vbt;
 
-	pci_unmap_rom(pdev, oprom);
+	drm_dbg_kms(display->drm, "Found valid VBT in %s\n", type);
 
-	if (sizep)
-		*sizep = vbt_size;
+	if (size)
+		*size = vbt_size;
 
-	drm_dbg_kms(display->drm, "Found valid VBT in PCI ROM\n");
+	intel_rom_free(rom);
 
 	return vbt;
 
 err_free_vbt:
 	kfree(vbt);
-err_unmap_oprom:
-	pci_unmap_rom(pdev, oprom);
-
+err_free_rom:
+	intel_rom_free(rom);
 	return NULL;
 }
 
@@ -3223,11 +3130,11 @@ static const struct vbt_header *intel_bios_get_vbt(struct intel_display *display
 	 */
 	if (!vbt && IS_DGFX(i915))
 		with_intel_runtime_pm(&i915->runtime_pm, wakeref)
-			vbt = spi_oprom_get_vbt(display, sizep);
+			vbt = oprom_get_vbt(display, intel_rom_spi(i915), sizep, "SPI flash");
 
 	if (!vbt)
 		with_intel_runtime_pm(&i915->runtime_pm, wakeref)
-			vbt = oprom_get_vbt(display, sizep);
+			vbt = oprom_get_vbt(display, intel_rom_pci(i915), sizep, "PCI ROM");
 
 	return vbt;
 }

drivers/gpu/drm/i915/soc/intel_rom.c

@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#include "i915_drv.h"
+#include "i915_reg.h"
+
+#include "intel_rom.h"
+#include "intel_uncore.h"
+
+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)
+{
+	pci_unmap_rom(rom->pdev, rom->oprom);
+}
+
+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 = to_pci_dev(i915->drm.dev);
+
+	rom->oprom = pci_map_rom(rom->pdev, &rom->size);
+	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);
+}

drivers/gpu/drm/i915/soc/intel_rom.h

@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#ifndef __INTEL_ROM_H__
+#define __INTEL_ROM_H__
+
+#include <linux/types.h>
+
+struct drm_i915_private;
+struct intel_rom;
+
+struct intel_rom *intel_rom_spi(struct drm_i915_private *i915);
+struct intel_rom *intel_rom_pci(struct drm_i915_private *i915);
+
+u32 intel_rom_read32(struct intel_rom *rom, loff_t offset);
+u16 intel_rom_read16(struct intel_rom *rom, loff_t offset);
+void intel_rom_read_block(struct intel_rom *rom, void *data,
+			  loff_t offset, size_t size);
+loff_t intel_rom_find(struct intel_rom *rom, u32 needle);
+size_t intel_rom_size(struct intel_rom *rom);
+void intel_rom_free(struct intel_rom *rom);
+
+#endif /* __INTEL_ROM_H__ */

drivers/gpu/drm/xe/Makefile

@@ -180,7 +180,8 @@ xe-$(CONFIG_DRM_XE_DISPLAY) += \
 # SOC code shared with i915
 xe-$(CONFIG_DRM_XE_DISPLAY) += \
 	i915-soc/intel_dram.o \
-	i915-soc/intel_pch.o
+	i915-soc/intel_pch.o \
+	i915-soc/intel_rom.o
 
 # Display code shared with i915
 xe-$(CONFIG_DRM_XE_DISPLAY) += \

drivers/gpu/drm/xe/compat-i915-headers/soc/intel_rom.h

@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#include "../../../i915/soc/intel_rom.h"