From: Rafał Miłecki <ra...@milecki.pl>

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 <ra...@milecki.pl>
---
 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 <ra...@milecki.pl>
 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....@linaro.org>
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 <ra...@milecki.pl>
+ */
+
+#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 <ra...@milecki.pl>
- */
-
-#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

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