[PATCH V2 5/5] nvmem: layouts: add U-Boot env layout

[Rafał Miłecki]

From: Rafał Miłecki <rafal@xxxxxxxxxx>

This patch moves all generic (NVMEM devices independent) code from NVMEM
device driver to NVMEM layout driver. Then it adds a simple NVMEM layout
code on top of it.

Thanks to proper layout it's possible to support U-Boot env data stored
on any kind of NVMEM device.

For backward compatibility with old DT bindings we need to keep old
NVMEM device driver functional. To avoid code duplication a parsing
function is exported and reused in it.

Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---
V2: Support new compatibles & use device_get_match_data() helper

IMPORTANT:
This is based on top of the:
[PATCH v6.8 1/2] nvmem: layouts: refactor .add_cells() callback arguments

 MAINTAINERS                        |   1 +
 drivers/nvmem/Kconfig              |   3 +-
 drivers/nvmem/layouts/Kconfig      |  11 ++
 drivers/nvmem/layouts/Makefile     |   1 +
 drivers/nvmem/layouts/u-boot-env.c | 204 +++++++++++++++++++++++++++++
 drivers/nvmem/layouts/u-boot-env.h |  15 +++
 drivers/nvmem/u-boot-env.c         | 158 +---------------------
 7 files changed, 235 insertions(+), 158 deletions(-)
 create mode 100644 drivers/nvmem/layouts/u-boot-env.c
 create mode 100644 drivers/nvmem/layouts/u-boot-env.h

diff --git a/MAINTAINERS b/MAINTAINERS
index b589218605b4..1f7e6d74cd51 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22282,6 +22282,7 @@ U-BOOT ENVIRONMENT VARIABLES
 M:	Rafał Miłecki <rafal@xxxxxxxxxx>
 S:	Maintained
 F:	Documentation/devicetree/bindings/nvmem/u-boot,env.yaml
+F:	drivers/nvmem/layouts/u-boot-env.c
 F:	drivers/nvmem/u-boot-env.c
 
 UACCE ACCELERATOR FRAMEWORK
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 283134498fbc..d2c384f58028 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -363,8 +363,7 @@ config NVMEM_SUNXI_SID
 config NVMEM_U_BOOT_ENV
 	tristate "U-Boot environment variables support"
 	depends on OF && MTD
-	select CRC32
-	select GENERIC_NET_UTILS
+	select NVMEM_LAYOUT_U_BOOT_ENV
 	help
 	  U-Boot stores its setup as environment variables. This driver adds
 	  support for verifying & exporting such data. It also exposes variables
diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig
index 9c6e672fc350..5e586dfebe47 100644
--- a/drivers/nvmem/layouts/Kconfig
+++ b/drivers/nvmem/layouts/Kconfig
@@ -26,6 +26,17 @@ config NVMEM_LAYOUT_ONIE_TLV
 
 	  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
index 2974bd7d33ed..4940c9db0665 100644
--- a/drivers/nvmem/layouts/Makefile
+++ b/drivers/nvmem/layouts/Makefile
@@ -5,3 +5,4 @@
 
 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/u-boot-env.c b/drivers/nvmem/layouts/u-boot-env.c
new file mode 100644
index 000000000000..dcd2ffed503c
--- /dev/null
+++ b/drivers/nvmem/layouts/u-boot-env.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 - 2023 Rafał Miłecki <rafal@xxxxxxxxxx>
+ */
+
+#include <linux/crc32.h>
+#include <linux/etherdevice.h>
+#include <linux/export.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 (bytes != 3 * ETH_ALEN - 1)
+		return -EINVAL;
+
+	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.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;
+	__le32 *crc32_addr;
+	size_t data_offset;
+	size_t data_len;
+	size_t dev_size;
+	uint32_t crc32;
+	uint32_t calc;
+	uint8_t *buf;
+	int bytes;
+	int err;
+
+	dev_size = nvmem_dev_size(nvmem);
+
+	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;
+	}
+	crc32_addr = (__le32 *)(buf + crc32_offset);
+	crc32 = le32_to_cpu(*crc32_addr);
+	crc32_data_len = dev_size - crc32_data_offset;
+	data_len = dev_size - data_offset;
+
+	calc = crc32(~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-layout", .data = (void *)U_BOOT_FORMAT_SINGLE, },
+	{ .compatible = "u-boot,env-redundant-bool-layout", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
+	{ .compatible = "u-boot,env-redundant-count-layout", .data = (void *)U_BOOT_FORMAT_REDUNDANT, },
+	{ .compatible = "brcm,env-layout", .data = (void *)U_BOOT_FORMAT_BROADCOM, },
+	{},
+};
+
+static struct nvmem_layout_driver u_boot_env_layout = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.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);
diff --git a/drivers/nvmem/layouts/u-boot-env.h b/drivers/nvmem/layouts/u-boot-env.h
new file mode 100644
index 000000000000..dd5f280ac047
--- /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 */
diff --git a/drivers/nvmem/u-boot-env.c b/drivers/nvmem/u-boot-env.c
index befbab156cda..386b2b255c30 100644
--- a/drivers/nvmem/u-boot-env.c
+++ b/drivers/nvmem/u-boot-env.c
@@ -3,23 +3,15 @@
  * Copyright (C) 2022 Rafał Miłecki <rafal@xxxxxxxxxx>
  */
 
-#include <linux/crc32.h>
-#include <linux/etherdevice.h>
-#include <linux/if_ether.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/mtd/mtd.h>
-#include <linux/nvmem-consumer.h>
 #include <linux/nvmem-provider.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 
-enum u_boot_env_format {
-	U_BOOT_FORMAT_SINGLE,
-	U_BOOT_FORMAT_REDUNDANT,
-	U_BOOT_FORMAT_BROADCOM,
-};
+#include "layouts/u-boot-env.h"
 
 struct u_boot_env {
 	struct device *dev;
@@ -29,24 +21,6 @@ struct u_boot_env {
 	struct mtd_info *mtd;
 };
 
-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(void *context, unsigned int offset, void *val,
 			   size_t bytes)
 {
@@ -69,134 +43,6 @@ static int u_boot_env_read(void *context, unsigned int offset, void *val,
 	return 0;
 }
 
-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 (bytes != 3 * ETH_ALEN - 1)
-		return -EINVAL;
-
-	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_add_cells(struct u_boot_env *priv, uint8_t *buf,
-				size_t data_offset, size_t data_len)
-{
-	struct nvmem_device *nvmem = priv->nvmem;
-	struct device *dev = priv->dev;
-	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.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;
-}
-
-static int u_boot_env_parse(struct u_boot_env *priv)
-{
-	struct nvmem_device *nvmem = priv->nvmem;
-	struct device *dev = priv->dev;
-	size_t crc32_data_offset;
-	size_t crc32_data_len;
-	size_t crc32_offset;
-	__le32 *crc32_addr;
-	size_t data_offset;
-	size_t data_len;
-	size_t dev_size;
-	uint32_t crc32;
-	uint32_t calc;
-	uint8_t *buf;
-	int bytes;
-	int err;
-
-	dev_size = nvmem_dev_size(nvmem);
-
-	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 (priv->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;
-	}
-	crc32_addr = (__le32 *)(buf + crc32_offset);
-	crc32 = le32_to_cpu(*crc32_addr);
-	crc32_data_len = dev_size - crc32_data_offset;
-	data_len = dev_size - data_offset;
-
-	calc = crc32(~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_add_cells(priv, buf, data_offset, data_len);
-
-err_kfree:
-	kfree(buf);
-err_out:
-	return err;
-}
-
 static int u_boot_env_probe(struct platform_device *pdev)
 {
 	struct nvmem_config config = {
@@ -228,7 +74,7 @@ static int u_boot_env_probe(struct platform_device *pdev)
 	if (IS_ERR(priv->nvmem))
 		return PTR_ERR(priv->nvmem);
 
-	return u_boot_env_parse(priv);
+	return u_boot_env_parse(dev, priv->nvmem, priv->format);
 }
 
 static const struct of_device_id u_boot_env_of_match_table[] = {
-- 
2.35.3