[PATCH WIP 3/3] nvmem: u-boot-env: convert to NVMEM layout

From: Rafał Miłecki
Date: Tue Jul 18 2023 - 12:07:22 EST

From: Rafał Miłecki <rafal@xxxxxxxxxx>

This avoids code duplication (NVMEM device access) and allows reusing
this on top of other NVMEM devices.

Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---
drivers/mtd/mtdcore.c | 7 ++
drivers/nvmem/Kconfig | 15 ++-
drivers/nvmem/Makefile | 2 -
drivers/nvmem/layouts/Kconfig | 10 ++
drivers/nvmem/layouts/Makefile | 1 +
drivers/nvmem/{ => layouts}/u-boot-env.c | 112 +++++++++--------------
6 files changed, 68 insertions(+), 79 deletions(-)
rename drivers/nvmem/{ => layouts}/u-boot-env.c (67%)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 3d781ffb8c32..5f96affdfb0f 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -556,6 +556,13 @@ static int mtd_nvmem_add(struct mtd_info *mtd)
config.ignore_wp = true;
config.priv = mtd;

+ if (IS_ENABLED(NVMEM_U_BOOT_ENV) &&
+ (of_device_is_compatible(node, "u-boot,env") ||
+ of_device_is_compatible(node, "brcm,env"))) {
+ /* FIXME */
+ pr_warn("Missing support for deprecated U-Boot env binding\n");
+ }
+
mtd->nvmem = nvmem_register(&config);
if (IS_ERR(mtd->nvmem)) {
/* Just ignore if there is no NVMEM support in the kernel */
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index da9befa3d6c4..ff99c284a582 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -347,18 +347,15 @@ config NVMEM_SUNXI_SID
will be called nvmem_sunxi_sid.

config NVMEM_U_BOOT_ENV
- tristate "U-Boot environment variables support"
+ bool "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
- as NVMEM cells so they can be referenced by other drivers.
-
- Currently this drivers works only with env variables on top of MTD.
+ This option enables support for the old device tree binding describing
+ U-Boot environment variables block on top of MTD partition.

- If compiled as module it will be called nvmem_u-boot-env.
+ Those bindings have been deprecated in favor of using a proper NVMEM
+ layout.

config NVMEM_UNIPHIER_EFUSE
tristate "UniPhier SoCs eFuse support"
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index cc23ce4ffb1f..2558752fd9a3 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -69,8 +69,6 @@ obj-$(CONFIG_NVMEM_SUNPLUS_OCOTP) += nvmem_sunplus_ocotp.o
nvmem_sunplus_ocotp-y := sunplus-ocotp.o
obj-$(CONFIG_NVMEM_SUNXI_SID) += nvmem_sunxi_sid.o
nvmem_sunxi_sid-y := sunxi_sid.o
-obj-$(CONFIG_NVMEM_U_BOOT_ENV) += nvmem_u-boot-env.o
-nvmem_u-boot-env-y := u-boot-env.o
obj-$(CONFIG_NVMEM_UNIPHIER_EFUSE) += nvmem-uniphier-efuse.o
nvmem-uniphier-efuse-y := uniphier-efuse.o
obj-$(CONFIG_NVMEM_VF610_OCOTP) += nvmem-vf610-ocotp.o
diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig
index 7ff1ee1c1f05..f33999be787e 100644
--- a/drivers/nvmem/layouts/Kconfig
+++ b/drivers/nvmem/layouts/Kconfig
@@ -20,4 +20,14 @@ config NVMEM_LAYOUT_ONIE_TLV

If unsure, say N.

+config NVMEM_LAYOUT_U_BOOT_ENV
+ tristate "U-Boot environment variables layout support"
+ depends on OF
+ 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.
+
endmenu
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/u-boot-env.c b/drivers/nvmem/layouts/u-boot-env.c
similarity index 67%
rename from drivers/nvmem/u-boot-env.c
rename to drivers/nvmem/layouts/u-boot-env.c
index ee9fd9989b6e..32eae6df8d96 100644
--- a/drivers/nvmem/u-boot-env.c
+++ b/drivers/nvmem/layouts/u-boot-env.c
@@ -8,11 +8,9 @@
#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_device.h>
-#include <linux/platform_device.h>
#include <linux/slab.h>

enum u_boot_env_format {
@@ -25,7 +23,7 @@ struct u_boot_env {
struct device *dev;
enum u_boot_env_format format;

- struct mtd_info *mtd;
+ struct nvmem_device *nvmem;

/* Cells */
struct nvmem_cell_info *cells;
@@ -50,28 +48,6 @@ struct u_boot_env_image_broadcom {
uint8_t data[0];
} __packed;

-static int u_boot_env_read(void *context, unsigned int offset, void *val,
- size_t bytes)
-{
- struct u_boot_env *priv = context;
- struct device *dev = priv->dev;
- size_t bytes_read;
- int err;
-
- err = mtd_read(priv->mtd, offset, bytes, &bytes_read, val);
- if (err && !mtd_is_bitflip(err)) {
- dev_err(dev, "Failed to read from mtd: %d\n", err);
- return err;
- }
-
- if (bytes_read != bytes) {
- dev_err(dev, "Failed to read %zu bytes\n", bytes);
- return -EIO;
- }
-
- 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)
{
@@ -95,17 +71,25 @@ static int u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf,
size_t data_offset, size_t data_len)
{
struct device *dev = priv->dev;
+ struct device_node *layout_np;
char *data = buf + data_offset;
char *var, *value, *eq;
+ int err = 0;
int idx;

+ layout_np = of_nvmem_layout_get_container(priv->nvmem);
+ if (!layout_np)
+ return -ENOENT;
+
priv->ncells = 0;
for (var = data; var < data + data_len && *var; var += strlen(var) + 1)
priv->ncells++;

priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
- if (!priv->cells)
- return -ENOMEM;
+ if (!priv->cells) {
+ err = -ENOMEM;
+ goto err_of_node_put;
+ }

for (var = data, idx = 0;
var < data + data_len && *var;
@@ -117,11 +101,13 @@ static int u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf,
value = eq + 1;

priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL);
- if (!priv->cells[idx].name)
- return -ENOMEM;
+ if (!priv->cells[idx].name) {
+ err = -ENOMEM;
+ goto err_of_node_put;
+ }
priv->cells[idx].offset = data_offset + value - data;
priv->cells[idx].bytes = strlen(value);
- priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
+ priv->cells[idx].np = of_get_child_by_name(layout_np, priv->cells[idx].name);
if (!strcmp(var, "ethaddr")) {
priv->cells[idx].raw_len = strlen(value);
priv->cells[idx].bytes = ETH_ALEN;
@@ -132,7 +118,10 @@ static int u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf,
if (WARN_ON(idx != priv->ncells))
priv->ncells = idx;

- return 0;
+err_of_node_put:
+ of_node_put(layout_np);
+
+ return err;
}

static int u_boot_env_parse(struct u_boot_env *priv)
@@ -143,21 +132,25 @@ static int u_boot_env_parse(struct u_boot_env *priv)
size_t crc32_offset;
size_t data_offset;
size_t data_len;
+ size_t env_size;
uint32_t crc32;
uint32_t calc;
- size_t bytes;
+ ssize_t bytes;
uint8_t *buf;
int err;

- buf = kcalloc(1, priv->mtd->size, GFP_KERNEL);
+ env_size = nvmem_device_size(priv->nvmem);
+
+ buf = kcalloc(1, env_size, GFP_KERNEL);
if (!buf) {
err = -ENOMEM;
goto err_out;
}

- err = mtd_read(priv->mtd, 0, priv->mtd->size, &bytes, buf);
- if ((err && !mtd_is_bitflip(err)) || bytes != priv->mtd->size) {
- dev_err(dev, "Failed to read from mtd: %d\n", err);
+ bytes = nvmem_device_read(priv->nvmem, 0, env_size, buf);
+ if (bytes < 0 || bytes != env_size) {
+ dev_err(dev, "Failed to read from NVMEM device: %zd\n", bytes);
+ err = -EIO;
goto err_kfree;
}

@@ -179,8 +172,8 @@ static int u_boot_env_parse(struct u_boot_env *priv)
break;
}
crc32 = le32_to_cpu(*(__le32 *)(buf + crc32_offset));
- crc32_data_len = priv->mtd->size - crc32_data_offset;
- data_len = priv->mtd->size - data_offset;
+ crc32_data_len = env_size - crc32_data_offset;
+ data_len = env_size - data_offset;

calc = crc32(~0, buf + crc32_data_offset, crc32_data_len) ^ ~0L;
if (calc != crc32) {
@@ -189,7 +182,7 @@ static int u_boot_env_parse(struct u_boot_env *priv)
goto err_kfree;
}

- buf[priv->mtd->size - 1] = '\0';
+ buf[env_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);
@@ -200,14 +193,9 @@ static int u_boot_env_parse(struct u_boot_env *priv)
return err;
}

-static int u_boot_env_probe(struct platform_device *pdev)
+static int u_boot_env_layout_add_cells(struct device *dev, struct nvmem_device *nvmem,
+ struct nvmem_layout *layout)
{
- struct nvmem_config config = {
- .name = "u-boot-env",
- .reg_read = u_boot_env_read,
- };
- struct device *dev = &pdev->dev;
- struct device_node *np = dev->of_node;
struct u_boot_env *priv;
int err;

@@ -216,28 +204,18 @@ static int u_boot_env_probe(struct platform_device *pdev)
return -ENOMEM;
priv->dev = dev;

- priv->format = (uintptr_t)of_device_get_match_data(dev);
+ priv->format = (uintptr_t)nvmem_layout_get_match_data(nvmem, layout);

- priv->mtd = of_get_mtd_device_by_node(np);
- if (IS_ERR(priv->mtd)) {
- dev_err_probe(dev, PTR_ERR(priv->mtd), "Failed to get %pOF MTD\n", np);
- return PTR_ERR(priv->mtd);
- }
+ priv->nvmem = nvmem;

err = u_boot_env_parse(priv);
if (err)
return err;

- config.dev = dev;
- config.cells = priv->cells;
- config.ncells = priv->ncells;
- config.priv = priv;
- config.size = priv->mtd->size;
-
- return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
+ return 0;
}

-static const struct of_device_id u_boot_env_of_match_table[] = {
+static const struct of_device_id u_boot_env_layout_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, },
@@ -245,15 +223,13 @@ static const struct of_device_id u_boot_env_of_match_table[] = {
{},
};

-static struct platform_driver u_boot_env_driver = {
- .probe = u_boot_env_probe,
- .driver = {
- .name = "u_boot_env",
- .of_match_table = u_boot_env_of_match_table,
- },
+static struct nvmem_layout u_boot_env_layout = {
+ .name = "u_boot_env",
+ .of_match_table = u_boot_env_layout_of_match_table,
+ .add_cells = u_boot_env_layout_add_cells,
};
-module_platform_driver(u_boot_env_driver);
+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_DEVICE_TABLE(of, u_boot_env_layout_of_match_table);
--
2.35.3