[PATCH V2 4/6] nvmem: u-boot-env: convert to layout driver

From: Rafał Miłecki
Date: Wed Jan 11 2023 - 02:31:38 EST

From: Rafał Miłecki <rafal@xxxxxxxxxx>

U-Boot environment variables can be found on various NVMEM devices (not
just MTD) so convert this driver to a generic layout one.

This way - thanks to using NVMEM generic API - this driver can be reused
in other scenarios.

For backward DT compatibility we need to support the old compatible
brinding string for now. Luckily it's just a one line of code.

Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---
MAINTAINERS | 2 +-
drivers/mtd/mtdcore.c | 7 +-
drivers/nvmem/Kconfig | 14 +-
drivers/nvmem/Makefile | 2 -
drivers/nvmem/layouts/Kconfig | 10 ++
drivers/nvmem/layouts/Makefile | 1 +
drivers/nvmem/layouts/u-boot-env.c | 176 ++++++++++++++++++++++
drivers/nvmem/u-boot-env.c | 233 -----------------------------
8 files changed, 199 insertions(+), 246 deletions(-)
create mode 100644 drivers/nvmem/layouts/u-boot-env.c
delete mode 100644 drivers/nvmem/u-boot-env.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 2e13ee875c77..ace29081c613 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21137,7 +21137,7 @@ U-BOOT ENVIRONMENT VARIABLES
M: Rafał Miłecki <rafal@xxxxxxxxxx>
S: Maintained
F: Documentation/devicetree/bindings/nvmem/layouts/u-boot,env.yaml
-F: drivers/nvmem/u-boot-env.c
+F: drivers/nvmem/layouts/u-boot-env.c

UACCE ACCELERATOR FRAMEWORK
M: Zhangfei Gao <zhangfei.gao@xxxxxxxxxx>
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 0feacb9fbdac..621e0b87b781 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -518,6 +518,11 @@ static int mtd_nvmem_add(struct mtd_info *mtd)
{
struct device_node *node = mtd_get_of_node(mtd);
struct nvmem_config config = {};
+ bool use_dev_of_node = false;
+
+ if (of_device_is_compatible(node, "nvmem-cells") ||
+ (IS_ENABLED(CONFIG_NVMEM_U_BOOT_ENV) && of_device_is_compatible(node, "brcm,env")))
+ use_dev_of_node = true;

config.id = -1;
config.dev = &mtd->dev;
@@ -530,7 +535,7 @@ static int mtd_nvmem_add(struct mtd_info *mtd)
config.read_only = true;
config.root_only = true;
config.ignore_wp = true;
- config.no_of_node = !of_device_is_compatible(node, "nvmem-cells");
+ config.no_of_node = !use_dev_of_node;
config.priv = mtd;

mtd->nvmem = nvmem_register(&config);
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 0e10b5b094b9..980734ba8ddc 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -327,17 +327,13 @@ 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 deprecated binding support"
depends on OF && MTD
- select CRC32
+ 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.
-
- If compiled as module it will be called nvmem_u-boot-env.
+ This option enables support for deprecated DT binding for U-Boot
+ environment variables. It was used by DT files before introducing
+ nvmem-layout node based syntax.

config NVMEM_UNIPHIER_EFUSE
tristate "UniPhier SoCs eFuse support"
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 4cf87ef6c24d..3b827ce96f6d 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -66,8 +66,6 @@ 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 9ad50474cb77..8a38c514943a 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
+ bool "U-Boot environment variables support"
+ select CRC32
+ 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
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..95c314553952
--- /dev/null
+++ b/drivers/nvmem/layouts/u-boot-env.c
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Rafał Miłecki <rafal@xxxxxxxxxx>
+ */
+
+#include <linux/crc32.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.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 {
+ U_BOOT_FORMAT_SINGLE,
+ U_BOOT_FORMAT_REDUNDANT,
+ U_BOOT_FORMAT_BROADCOM,
+};
+
+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;
+ uint8_t data[];
+} __packed;
+
+static int u_boot_env_parse_data(struct device *dev, struct nvmem_device *nvmem, uint8_t *buf,
+ size_t data_offset, size_t data_len)
+{
+ struct device_node *np;
+ char *data = buf + data_offset;
+ char *var, *value, *eq;
+ int err = 0;
+
+ np = of_nvmem_layout_get_container(nvmem);
+ if (!np)
+ return -ENOENT;
+
+ 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) {
+ err = -ENOMEM;
+ break;
+ }
+ info.offset = data_offset + value - data;
+ info.bytes = strlen(value);
+ info.np = of_get_child_by_name(np, info.name);
+
+ err = nvmem_add_one_cell(nvmem, &info);
+ if (err) {
+ dev_err(dev, "Failed to add \"%s\" cell: %d\n", info.name, err);
+ break;
+ }
+ }
+
+ of_node_put(np);
+
+ return err;
+}
+
+static int u_boot_env_add_cells(struct device *dev, struct nvmem_device *nvmem,
+ struct nvmem_layout *layout)
+{
+ 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;
+ size_t bytes;
+ uint8_t *buf;
+ int err;
+
+ format = (uintptr_t)nvmem_layout_get_match_data(nvmem, layout);
+
+ 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 || bytes != dev_size) {
+ dev_err(dev, "Failed to read from NVMEM device: %zd\n", bytes);
+ 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 = 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_data(dev, nvmem, buf, data_offset, data_len);
+ if (err)
+ dev_err(dev, "Failed to parse cells: %d\n", err);
+
+err_kfree:
+ kfree(buf);
+err_out:
+ return err;
+}
+
+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 u_boot_env_layout = {
+ .name = "U-Boot environment variables layout",
+ .of_match_table = u_boot_env_of_match_table,
+ .add_cells = u_boot_env_add_cells,
+};
+
+static int __init u_boot_env_init(void)
+{
+ return nvmem_layout_register(&u_boot_env_layout);
+}
+subsys_initcall(u_boot_env_init);
+
+MODULE_AUTHOR("Rafał Miłecki");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table);
diff --git a/drivers/nvmem/u-boot-env.c b/drivers/nvmem/u-boot-env.c
deleted file mode 100644
index 29b1d87a3c51..000000000000
--- a/drivers/nvmem/u-boot-env.c
+++ /dev/null
@@ -1,233 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Copyright (C) 2022 Rafał Miłecki <rafal@xxxxxxxxxx>
- */
-
-#include <linux/crc32.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 {
- U_BOOT_FORMAT_SINGLE,
- U_BOOT_FORMAT_REDUNDANT,
- U_BOOT_FORMAT_BROADCOM,
-};
-
-struct u_boot_env {
- struct device *dev;
- enum u_boot_env_format format;
-
- struct mtd_info *mtd;
-
- /* Cells */
- struct nvmem_cell_info *cells;
- int ncells;
-};
-
-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;
- 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_add_cells(struct u_boot_env *priv, uint8_t *buf,
- size_t data_offset, size_t data_len)
-{
- struct device *dev = priv->dev;
- char *data = buf + data_offset;
- char *var, *value, *eq;
- int idx;
-
- 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;
-
- for (var = data, idx = 0;
- var < data + data_len && *var;
- var = value + strlen(value) + 1, idx++) {
- eq = strchr(var, '=');
- if (!eq)
- break;
- *eq = '\0';
- value = eq + 1;
-
- priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL);
- if (!priv->cells[idx].name)
- return -ENOMEM;
- 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);
- }
-
- if (WARN_ON(idx != priv->ncells))
- priv->ncells = idx;
-
- return 0;
-}
-
-static int u_boot_env_parse(struct u_boot_env *priv)
-{
- 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;
- uint32_t crc32;
- uint32_t calc;
- size_t bytes;
- uint8_t *buf;
- int err;
-
- buf = kcalloc(1, priv->mtd->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);
- 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 = le32_to_cpu(*(__le32 *)(buf + crc32_offset));
- crc32_data_len = priv->mtd->size - crc32_data_offset;
- data_len = priv->mtd->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[priv->mtd->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 = {
- .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;
-
- priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
- if (!priv)
- return -ENOMEM;
- priv->dev = dev;
-
- priv->format = (uintptr_t)of_device_get_match_data(dev);
-
- 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);
- }
-
- 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));
-}
-
-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 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,
- },
-};
-module_platform_driver(u_boot_env_driver);
-
-MODULE_AUTHOR("Rafał Miłecki");
-MODULE_LICENSE("GPL");
-MODULE_DEVICE_TABLE(of, u_boot_env_of_match_table);
--
2.34.1