drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validationgrafted

amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and
uses the first encoding that validates. YCbCr 4:4:4 is listed before
RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the
"color format" property is left at AUTO, even though RGB fits the same
link.

That contradicts the documented AUTO behaviour for HDMI in enum
drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when
the bandwidth is not available or the mode is 4:2:0-only), which the
amdgpu implementation of the property also describes. It also leaves
the "Broadcast RGB" property without effect on such sinks, since the
quantization range it selects only applies to RGB output.

Try RGB first. The mask still holds every encoding the sink supports,
so a mode that cannot carry RGB falls back exactly as before.

For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced
through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI
sink that advertised it.

Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation")
Suggested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Assisted-by: Claude Code:claude-fable-5-1
Signed-off-by: Adrian Betschart <adrian.betschart@cinemaone.ch>
Reviewed-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7)

7 files changed, 765 insertions, 0 deletions

diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig
new file mode 100644
index 000000000..5e586dfeb
--- /dev/null
+++ b/drivers/nvmem/layouts/Kconfig
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config NVMEM_LAYOUTS
+	bool
+	depends on OF
+
+if NVMEM_LAYOUTS
+
+menu "Layout Types"
+
+config NVMEM_LAYOUT_SL28_VPD
+	tristate "Kontron sl28 VPD layout support"
+	select CRC8
+	help
+	  Say Y here if you want to support the VPD layout of the Kontron
+	  SMARC-sAL28 boards.
+
+	  If unsure, say N.
+
+config NVMEM_LAYOUT_ONIE_TLV
+	tristate "ONIE tlv support"
+	select CRC32
+	help
+	  Say Y here if you want to support the Open Compute Project ONIE
+	  Type-Length-Value standard table.
+
+	  If unsure, say N.
+
+config NVMEM_LAYOUT_U_BOOT_ENV
+	tristate "U-Boot environment variables layout"
+	select CRC32
+	select GENERIC_NET_UTILS
+	help
+	  U-Boot stores its setup as environment variables. This driver adds
+	  support for verifying & exporting such data. It also exposes variables
+	  as NVMEM cells so they can be referenced by other drivers.
+
+	  If unsure, say N.
+
+endmenu
+
+endif
diff --git a/drivers/nvmem/layouts/Makefile b/drivers/nvmem/layouts/Makefile
new file mode 100644
index 000000000..dd6c6c70b
--- /dev/null
+++ b/drivers/nvmem/layouts/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for nvmem layouts.
+#
+
+obj-$(CONFIG_NVMEM_LAYOUTS) += fixed-layout.o
+obj-$(CONFIG_NVMEM_LAYOUT_SL28_VPD) += sl28vpd.o
+obj-$(CONFIG_NVMEM_LAYOUT_ONIE_TLV) += onie-tlv.o
+obj-$(CONFIG_NVMEM_LAYOUT_U_BOOT_ENV) += u-boot-env.o
diff --git a/drivers/nvmem/layouts/fixed-layout.c b/drivers/nvmem/layouts/fixed-layout.c
new file mode 100644
index 000000000..635d448b3
--- /dev/null
+++ b/drivers/nvmem/layouts/fixed-layout.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2026 Bootlin
+ *
+ * Authors: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
+ */
+
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+
+#include "../internals.h"
+
+static int fixed_layout_add_cells(struct nvmem_layout *layout)
+{
+	struct device_node *np;
+	int ret;
+
+	np = of_nvmem_layout_get_container(layout->nvmem);
+	if (!np)
+		return -ENOENT;
+
+	ret = nvmem_add_cells_from_dt(layout->nvmem, np);
+	of_node_put(np);
+
+	return ret;
+}
+
+static int fixed_layout_probe(struct nvmem_layout *layout)
+{
+	layout->add_cells = fixed_layout_add_cells;
+
+	return nvmem_layout_register(layout);
+}
+
+static void fixed_layout_remove(struct nvmem_layout *layout)
+{
+	nvmem_layout_unregister(layout);
+}
+
+static const struct of_device_id fixed_layout_of_match_table[] = {
+	{ .compatible = "fixed-layout", },
+	{},
+};
+
+static struct nvmem_layout_driver fixed_layout_layout = {
+	.driver = {
+		.name = "fixed-layout",
+		.of_match_table = fixed_layout_of_match_table,
+	},
+	.probe = fixed_layout_probe,
+	.remove = fixed_layout_remove,
+};
+module_nvmem_layout_driver(fixed_layout_layout);
+
+MODULE_AUTHOR("Mathieu Dubois-Briand");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(of, fixed_layout_of_match_table);
+MODULE_DESCRIPTION("NVMEM fixed-layout driver");
diff --git a/drivers/nvmem/layouts/onie-tlv.c b/drivers/nvmem/layouts/onie-tlv.c
new file mode 100644
index 000000000..8b0f3c1b8
--- /dev/null
+++ b/drivers/nvmem/layouts/onie-tlv.c
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ONIE tlv NVMEM cells provider
+ *
+ * Copyright (C) 2022 Open Compute Group ONIE
+ * Author: Miquel Raynal <miquel.raynal@bootlin.com>
+ * Based on the nvmem driver written by: Vadym Kochan <vadym.kochan@plvision.eu>
+ * Inspired by the first layout written by: Rafał Miłecki <rafal@milecki.pl>
+ */
+
+#include <linux/crc32.h>
+#include <linux/etherdevice.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+
+#define ONIE_TLV_MAX_LEN 2048
+#define ONIE_TLV_CRC_FIELD_SZ 6
+#define ONIE_TLV_CRC_SZ 4
+#define ONIE_TLV_HDR_ID	"TlvInfo"
+
+struct onie_tlv_hdr {
+	u8 id[8];
+	u8 version;
+	__be16 data_len;
+} __packed;
+
+struct onie_tlv {
+	u8 type;
+	u8 len;
+} __packed;
+
+static const char *onie_tlv_cell_name(u8 type)
+{
+	switch (type) {
+	case 0x21:
+		return "product-name";
+	case 0x22:
+		return "part-number";
+	case 0x23:
+		return "serial-number";
+	case 0x24:
+		return "mac-address";
+	case 0x25:
+		return "manufacture-date";
+	case 0x26:
+		return "device-version";
+	case 0x27:
+		return "label-revision";
+	case 0x28:
+		return "platform-name";
+	case 0x29:
+		return "onie-version";
+	case 0x2A:
+		return "num-macs";
+	case 0x2B:
+		return "manufacturer";
+	case 0x2C:
+		return "country-code";
+	case 0x2D:
+		return "vendor";
+	case 0x2E:
+		return "diag-version";
+	case 0x2F:
+		return "service-tag";
+	case 0xFD:
+		return "vendor-extension";
+	case 0xFE:
+		return "crc32";
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+static int onie_tlv_mac_read_cb(void *priv, const char *id, int index,
+				unsigned int offset, void *buf,
+				size_t bytes)
+{
+	eth_addr_add(buf, index);
+
+	return 0;
+}
+
+static nvmem_cell_post_process_t onie_tlv_read_cb(u8 type, u8 *buf)
+{
+	switch (type) {
+	case 0x24:
+		return &onie_tlv_mac_read_cb;
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+static int onie_tlv_add_cells(struct device *dev, struct nvmem_device *nvmem,
+			      size_t data_len, u8 *data)
+{
+	struct nvmem_cell_info cell = {};
+	struct device_node *layout;
+	struct onie_tlv tlv;
+	unsigned int hdr_len = sizeof(struct onie_tlv_hdr);
+	unsigned int offset = 0;
+	int ret;
+
+	layout = of_nvmem_layout_get_container(nvmem);
+	if (!layout)
+		return -ENOENT;
+
+	while (offset < data_len) {
+		memcpy(&tlv, data + offset, sizeof(tlv));
+		if (offset + tlv.len >= data_len) {
+			dev_err(dev, "Out of bounds field (0x%x bytes at 0x%x)\n",
+				tlv.len, hdr_len + offset);
+			break;
+		}
+
+		cell.name = onie_tlv_cell_name(tlv.type);
+		if (!cell.name)
+			goto next;
+
+		cell.offset = hdr_len + offset + sizeof(tlv.type) + sizeof(tlv.len);
+		cell.bytes = tlv.len;
+		cell.np = of_get_child_by_name(layout, cell.name);
+		cell.read_post_process = onie_tlv_read_cb(tlv.type, data + offset + sizeof(tlv));
+
+		ret = nvmem_add_one_cell(nvmem, &cell);
+		if (ret) {
+			of_node_put(layout);
+			return ret;
+		}
+
+next:
+		offset += sizeof(tlv) + tlv.len;
+	}
+
+	of_node_put(layout);
+
+	return 0;
+}
+
+static bool onie_tlv_hdr_is_valid(struct device *dev, struct onie_tlv_hdr *hdr)
+{
+	if (memcmp(hdr->id, ONIE_TLV_HDR_ID, sizeof(hdr->id))) {
+		dev_err(dev, "Invalid header\n");
+		return false;
+	}
+
+	if (hdr->version != 0x1) {
+		dev_err(dev, "Invalid version number\n");
+		return false;
+	}
+
+	return true;
+}
+
+static bool onie_tlv_crc_is_valid(struct device *dev, size_t table_len, u8 *table)
+{
+	struct onie_tlv crc_hdr;
+	u32 read_crc, calc_crc;
+	__be32 crc_be;
+
+	memcpy(&crc_hdr, table + table_len - ONIE_TLV_CRC_FIELD_SZ, sizeof(crc_hdr));
+	if (crc_hdr.type != 0xfe || crc_hdr.len != ONIE_TLV_CRC_SZ) {
+		dev_err(dev, "Invalid CRC field\n");
+		return false;
+	}
+
+	/* The table contains a JAMCRC, which is XOR'ed compared to the original
+	 * CRC32 implementation as known in the Ethernet world.
+	 */
+	memcpy(&crc_be, table + table_len - ONIE_TLV_CRC_SZ, ONIE_TLV_CRC_SZ);
+	read_crc = be32_to_cpu(crc_be);
+	calc_crc = crc32(~0, table, table_len - ONIE_TLV_CRC_SZ) ^ 0xFFFFFFFF;
+	if (read_crc != calc_crc) {
+		dev_err(dev, "Invalid CRC read: 0x%08x, expected: 0x%08x\n",
+			read_crc, calc_crc);
+		return false;
+	}
+
+	return true;
+}
+
+static int onie_tlv_parse_table(struct nvmem_layout *layout)
+{
+	struct nvmem_device *nvmem = layout->nvmem;
+	struct device *dev = &layout->dev;
+	struct onie_tlv_hdr hdr;
+	size_t table_len, data_len, hdr_len;
+	u8 *table, *data;
+	int ret;
+
+	ret = nvmem_device_read(nvmem, 0, sizeof(hdr), &hdr);
+	if (ret < 0)
+		return ret;
+
+	if (!onie_tlv_hdr_is_valid(dev, &hdr)) {
+		dev_err(dev, "Invalid ONIE TLV header\n");
+		return -EINVAL;
+	}
+
+	hdr_len = sizeof(hdr.id) + sizeof(hdr.version) + sizeof(hdr.data_len);
+	data_len = be16_to_cpu(hdr.data_len);
+	table_len = hdr_len + data_len;
+	if (table_len > ONIE_TLV_MAX_LEN) {
+		dev_err(dev, "Invalid ONIE TLV data length\n");
+		return -EINVAL;
+	}
+
+	table = devm_kmalloc(dev, table_len, GFP_KERNEL);
+	if (!table)
+		return -ENOMEM;
+
+	ret = nvmem_device_read(nvmem, 0, table_len, table);
+	if (ret != table_len)
+		return ret;
+
+	if (!onie_tlv_crc_is_valid(dev, table_len, table))
+		return -EINVAL;
+
+	data = table + hdr_len;
+	ret = onie_tlv_add_cells(dev, nvmem, data_len, data);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int onie_tlv_probe(struct nvmem_layout *layout)
+{
+	layout->add_cells = onie_tlv_parse_table;
+
+	return nvmem_layout_register(layout);
+}
+
+static void onie_tlv_remove(struct nvmem_layout *layout)
+{
+	nvmem_layout_unregister(layout);
+}
+
+static const struct of_device_id onie_tlv_of_match_table[] = {
+	{ .compatible = "onie,tlv-layout", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, onie_tlv_of_match_table);
+
+static struct nvmem_layout_driver onie_tlv_layout = {
+	.driver = {
+		.name = "onie-tlv-layout",
+		.of_match_table = onie_tlv_of_match_table,
+	},
+	.probe = onie_tlv_probe,
+	.remove = onie_tlv_remove,
+};
+module_nvmem_layout_driver(onie_tlv_layout);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com>");
+MODULE_DESCRIPTION("NVMEM layout driver for Onie TLV table parsing");
diff --git a/drivers/nvmem/layouts/sl28vpd.c b/drivers/nvmem/layouts/sl28vpd.c
new file mode 100644
index 000000000..e93b020b0
--- /dev/null
+++ b/drivers/nvmem/layouts/sl28vpd.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/crc8.h>
+#include <linux/etherdevice.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <uapi/linux/if_ether.h>
+
+#define SL28VPD_MAGIC 'V'
+
+struct sl28vpd_header {
+	u8 magic;
+	u8 version;
+} __packed;
+
+struct sl28vpd_v1 {
+	struct sl28vpd_header header;
+	char serial_number[15];
+	u8 base_mac_address[ETH_ALEN];
+	u8 crc8;
+} __packed;
+
+static int sl28vpd_mac_address_pp(void *priv, const char *id, int index,
+				  unsigned int offset, void *buf,
+				  size_t bytes)
+{
+	if (bytes != ETH_ALEN)
+		return -EINVAL;
+
+	if (index < 0)
+		return -EINVAL;
+
+	if (!is_valid_ether_addr(buf))
+		return -EINVAL;
+
+	eth_addr_add(buf, index);
+
+	return 0;
+}
+
+static const struct nvmem_cell_info sl28vpd_v1_entries[] = {
+	{
+		.name = "serial-number",
+		.offset = offsetof(struct sl28vpd_v1, serial_number),
+		.bytes = sizeof_field(struct sl28vpd_v1, serial_number),
+	},
+	{
+		.name = "base-mac-address",
+		.offset = offsetof(struct sl28vpd_v1, base_mac_address),
+		.bytes = sizeof_field(struct sl28vpd_v1, base_mac_address),
+		.read_post_process = sl28vpd_mac_address_pp,
+	},
+};
+
+static int sl28vpd_v1_check_crc(struct device *dev, struct nvmem_device *nvmem)
+{
+	struct sl28vpd_v1 data_v1;
+	u8 table[CRC8_TABLE_SIZE];
+	int ret;
+	u8 crc;
+
+	crc8_populate_msb(table, 0x07);
+
+	ret = nvmem_device_read(nvmem, 0, sizeof(data_v1), &data_v1);
+	if (ret < 0)
+		return ret;
+	else if (ret != sizeof(data_v1))
+		return -EIO;
+
+	crc = crc8(table, (void *)&data_v1, sizeof(data_v1) - 1, 0);
+
+	if (crc != data_v1.crc8) {
+		dev_err(dev,
+			"Checksum is invalid (got %02x, expected %02x).\n",
+			crc, data_v1.crc8);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int sl28vpd_add_cells(struct nvmem_layout *layout)
+{
+	struct nvmem_device *nvmem = layout->nvmem;
+	struct device *dev = &layout->dev;
+	const struct nvmem_cell_info *pinfo;
+	struct nvmem_cell_info info = {0};
+	struct device_node *layout_np;
+	struct sl28vpd_header hdr;
+	int ret, i;
+
+	/* check header */
+	ret = nvmem_device_read(nvmem, 0, sizeof(hdr), &hdr);
+	if (ret < 0)
+		return ret;
+	else if (ret != sizeof(hdr))
+		return -EIO;
+
+	if (hdr.magic != SL28VPD_MAGIC) {
+		dev_err(dev, "Invalid magic value (%02x)\n", hdr.magic);
+		return -EINVAL;
+	}
+
+	if (hdr.version != 1) {
+		dev_err(dev, "Version %d is unsupported.\n", hdr.version);
+		return -EINVAL;
+	}
+
+	ret = sl28vpd_v1_check_crc(dev, nvmem);
+	if (ret)
+		return ret;
+
+	layout_np = of_nvmem_layout_get_container(nvmem);
+	if (!layout_np)
+		return -ENOENT;
+
+	for (i = 0; i < ARRAY_SIZE(sl28vpd_v1_entries); i++) {
+		pinfo = &sl28vpd_v1_entries[i];
+
+		info.name = pinfo->name;
+		info.offset = pinfo->offset;
+		info.bytes = pinfo->bytes;
+		info.read_post_process = pinfo->read_post_process;
+		info.np = of_get_child_by_name(layout_np, pinfo->name);
+
+		ret = nvmem_add_one_cell(nvmem, &info);
+		if (ret) {
+			of_node_put(layout_np);
+			return ret;
+		}
+	}
+
+	of_node_put(layout_np);
+
+	return 0;
+}
+
+static int sl28vpd_probe(struct nvmem_layout *layout)
+{
+	layout->add_cells = sl28vpd_add_cells;
+
+	return nvmem_layout_register(layout);
+}
+
+static void sl28vpd_remove(struct nvmem_layout *layout)
+{
+	nvmem_layout_unregister(layout);
+}
+
+static const struct of_device_id sl28vpd_of_match_table[] = {
+	{ .compatible = "kontron,sl28-vpd" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sl28vpd_of_match_table);
+
+static struct nvmem_layout_driver sl28vpd_layout = {
+	.driver = {
+		.name = "kontron-sl28vpd-layout",
+		.of_match_table = sl28vpd_of_match_table,
+	},
+	.probe = sl28vpd_probe,
+	.remove = sl28vpd_remove,
+};
+module_nvmem_layout_driver(sl28vpd_layout);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
+MODULE_DESCRIPTION("NVMEM layout driver for the VPD of Kontron sl28 boards");
diff --git a/drivers/nvmem/layouts/u-boot-env.c b/drivers/nvmem/layouts/u-boot-env.c
new file mode 100644
index 000000000..33ec23503
--- /dev/null
+++ b/drivers/nvmem/layouts/u-boot-env.c
@@ -0,0 +1,211 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 - 2023 Rafał Miłecki <rafal@milecki.pl>
+ */
+
+#include <linux/crc32.h>
+#include <linux/etherdevice.h>
+#include <linux/export.h>
+#include <linux/hex.h>
+#include <linux/if_ether.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#include "u-boot-env.h"
+
+struct u_boot_env_image_single {
+	__le32 crc32;
+	uint8_t data[];
+} __packed;
+
+struct u_boot_env_image_redundant {
+	__le32 crc32;
+	u8 mark;
+	uint8_t data[];
+} __packed;
+
+struct u_boot_env_image_broadcom {
+	__le32 magic;
+	__le32 len;
+	__le32 crc32;
+	DECLARE_FLEX_ARRAY(uint8_t, data);
+} __packed;
+
+static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, int index,
+						unsigned int offset, void *buf, size_t bytes)
+{
+	u8 mac[ETH_ALEN];
+
+	if (!mac_pton(buf, mac))
+		return -EINVAL;
+
+	if (index)
+		eth_addr_add(mac, index);
+
+	ether_addr_copy(buf, mac);
+
+	return 0;
+}
+
+static int u_boot_env_parse_cells(struct device *dev, struct nvmem_device *nvmem, uint8_t *buf,
+				  size_t data_offset, size_t data_len)
+{
+	char *data = buf + data_offset;
+	char *var, *value, *eq;
+
+	for (var = data;
+	     var < data + data_len && *var;
+	     var = value + strlen(value) + 1) {
+		struct nvmem_cell_info info = {};
+
+		eq = strchr(var, '=');
+		if (!eq)
+			break;
+		*eq = '\0';
+		value = eq + 1;
+
+		info.name = devm_kstrdup(dev, var, GFP_KERNEL);
+		if (!info.name)
+			return -ENOMEM;
+		info.offset = data_offset + value - data;
+		info.bytes = strlen(value);
+		info.np = of_get_child_by_name(dev->of_node, info.name);
+		if (!strcmp(var, "ethaddr") && info.bytes == MAC_ADDR_STR_LEN) {
+			info.raw_len = strlen(value);
+			info.bytes = ETH_ALEN;
+			info.read_post_process = u_boot_env_read_post_process_ethaddr;
+		}
+
+		nvmem_add_one_cell(nvmem, &info);
+	}
+
+	return 0;
+}
+
+int u_boot_env_parse(struct device *dev, struct nvmem_device *nvmem,
+		     enum u_boot_env_format format)
+{
+	size_t crc32_data_offset;
+	size_t crc32_data_len;
+	size_t crc32_offset;
+	uint32_t *crc32_addr;
+	size_t data_offset;
+	size_t data_len;
+	size_t dev_size;
+	uint32_t crc32;
+	uint32_t calc;
+	uint8_t *buf;
+	u32 env_size;
+	int bytes;
+	int err;
+
+	dev_size = device_property_read_u32(dev, "env-size", &env_size) ?
+		nvmem_dev_size(nvmem) : (size_t)env_size;
+
+	buf = kzalloc(dev_size, GFP_KERNEL);
+	if (!buf) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+
+	bytes = nvmem_device_read(nvmem, 0, dev_size, buf);
+	if (bytes < 0) {
+		err = bytes;
+		goto err_kfree;
+	} else if (bytes != dev_size) {
+		err = -EIO;
+		goto err_kfree;
+	}
+
+	switch (format) {
+	case U_BOOT_FORMAT_SINGLE:
+		crc32_offset = offsetof(struct u_boot_env_image_single, crc32);
+		crc32_data_offset = offsetof(struct u_boot_env_image_single, data);
+		data_offset = offsetof(struct u_boot_env_image_single, data);
+		break;
+	case U_BOOT_FORMAT_REDUNDANT:
+		crc32_offset = offsetof(struct u_boot_env_image_redundant, crc32);
+		crc32_data_offset = offsetof(struct u_boot_env_image_redundant, data);
+		data_offset = offsetof(struct u_boot_env_image_redundant, data);
+		break;
+	case U_BOOT_FORMAT_BROADCOM:
+		crc32_offset = offsetof(struct u_boot_env_image_broadcom, crc32);
+		crc32_data_offset = offsetof(struct u_boot_env_image_broadcom, data);
+		data_offset = offsetof(struct u_boot_env_image_broadcom, data);
+		break;
+	}
+
+	if (dev_size < data_offset) {
+		dev_err(dev, "Device too small for u-boot-env\n");
+		err = -EIO;
+		goto err_kfree;
+	}
+
+	crc32_addr = (uint32_t *)(buf + crc32_offset);
+	crc32 = *crc32_addr;
+	crc32_data_len = dev_size - crc32_data_offset;
+	data_len = dev_size - data_offset;
+
+	calc = crc32_le(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L;
+	if (calc != crc32) {
+		dev_err(dev, "Invalid calculated CRC32: 0x%08x (expected: 0x%08x)\n", calc, crc32);
+		err = -EINVAL;
+		goto err_kfree;
+	}
+
+	buf[dev_size - 1] = '\0';
+	err = u_boot_env_parse_cells(dev, nvmem, buf, data_offset, data_len);
+
+err_kfree:
+	kfree(buf);
+err_out:
+	return err;
+}
+EXPORT_SYMBOL_GPL(u_boot_env_parse);
+
+static int u_boot_env_add_cells(struct nvmem_layout *layout)
+{
+	struct device *dev = &layout->dev;
+	enum u_boot_env_format format;
+
+	format = (uintptr_t)device_get_match_data(dev);
+
+	return u_boot_env_parse(dev, layout->nvmem, format);
+}
+
+static int u_boot_env_probe(struct nvmem_layout *layout)
+{
+	layout->add_cells = u_boot_env_add_cells;
+
+	return nvmem_layout_register(layout);
+}
+
+static void u_boot_env_remove(struct nvmem_layout *layout)
+{
+	nvmem_layout_unregister(layout);
+}
+
+static const struct of_device_id u_boot_env_of_match_table[] = {
+	{ .compatible = "u-boot,env", .data = (void *)U_BOOT_FORMAT_SINGLE, },
+	{ .compatible = "u-boot,env-redundant-bool", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
+	{ .compatible = "u-boot,env-redundant-count", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
+	{ .compatible = "brcm,env", .data = (void *)U_BOOT_FORMAT_BROADCOM, },
+	{},
+};
+
+static struct nvmem_layout_driver u_boot_env_layout = {
+	.driver = {
+		.name = "u-boot-env-layout",
+		.of_match_table = u_boot_env_of_match_table,
+	},
+	.probe = u_boot_env_probe,
+	.remove = u_boot_env_remove,
+};
+module_nvmem_layout_driver(u_boot_env_layout);
+
+MODULE_AUTHOR("Rafał Miłecki");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table);
+MODULE_DESCRIPTION("NVMEM layout driver for U-Boot environment variables");
diff --git a/drivers/nvmem/layouts/u-boot-env.h b/drivers/nvmem/layouts/u-boot-env.h
new file mode 100644
index 000000000..dd5f280ac
--- /dev/null
+++ b/drivers/nvmem/layouts/u-boot-env.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _LINUX_NVMEM_LAYOUTS_U_BOOT_ENV_H
+#define _LINUX_NVMEM_LAYOUTS_U_BOOT_ENV_H
+
+enum u_boot_env_format {
+	U_BOOT_FORMAT_SINGLE,
+	U_BOOT_FORMAT_REDUNDANT,
+	U_BOOT_FORMAT_BROADCOM,
+};
+
+int u_boot_env_parse(struct device *dev, struct nvmem_device *nvmem,
+		     enum u_boot_env_format format);
+
+#endif  /* ifndef _LINUX_NVMEM_LAYOUTS_U_BOOT_ENV_H */