[PATCH 4/4] nvmem: layouts: add U-Boot env layout

Rafał Miłecki
2023-12-18T13:37:48Z

From: Rafał Miłecki <rafal@milecki.pl>

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@milecki.pl>
---
MAINTAINERS | 1 +
drivers/nvmem/Kconfig | 3 +-
drivers/nvmem/layouts/Kconfig | 11 ++
drivers/nvmem/layouts/Makefile | 1 +
drivers/nvmem/layouts/u-boot-env.c | 212 +++++++++++++++++++++++++++++
drivers/nvmem/layouts/u-boot-env.h | 15 ++
drivers/nvmem/u-boot-env.c | 155 +--------------------
7 files changed, 243 insertions(+), 155 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@milecki.pl>
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..1787cfaf45f8
--- /dev/null
+++ b/drivers/nvmem/layouts/u-boot-env.c
@@ -0,0 +1,212 @@
+// 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/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 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 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;
+ 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 = kcalloc(1, dev_size, GFP_KERNEL);
+ if (!buf) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+
+ bytes = nvmem_device_read(nvmem, 0, dev_size, buf);
+ if (bytes < 0)
+ return bytes;
+ else if (bytes != dev_size)
+ return -EIO;
+
+ 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 = le32_to_cpu(*(__le32 *)(buf + crc32_offset));
+ 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);
+ if (err)
+ dev_err(dev, "Failed to add cells: %d\n", err);
+
+err_kfree:
+ kfree(buf);
+err_out:
+ return err;
+}
+EXPORT_SYMBOL_GPL(u_boot_env_parse);
+
+static int u_boot_env_add_cells(struct device *dev, struct nvmem_device *nvmem)
+{
+ const struct of_device_id *match;
+ struct device_node *layout_np;
+ enum u_boot_env_format format;
+
+ layout_np = of_nvmem_layout_get_container(nvmem);
+ if (!layout_np)
+ return -ENOENT;
+
+ match = of_match_node(u_boot_env_of_match_table, layout_np);
+ if (!match)
+ return -ENOENT;
+
+ format = (uintptr_t)match->data;
+
+ of_node_put(layout_np);
+
+ return u_boot_env_parse(dev, 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 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 ab8c9bf63d99..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@milecki.pl>
*/

-#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)
{
@@ -69,131 +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;
- 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 = kcalloc(1, dev_size, GFP_KERNEL);
- if (!buf) {
- err = -ENOMEM;
- goto err_out;
- }
-
- bytes = nvmem_device_read(nvmem, 0, dev_size, buf);
- if (bytes < 0)
- return bytes;
- else if (bytes != dev_size)
- return -EIO;
-
- 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 = le32_to_cpu(*(__le32 *)(buf + crc32_offset));
- 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);
- if (err)
- dev_err(dev, "Failed to add cells: %d\n", err);
-
-err_kfree:
- kfree(buf);
-err_out:
- return err;
-}
-
static int u_boot_env_probe(struct platform_device *pdev)
{
struct nvmem_config config = {
@@ -225,7 +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