From: Rafał Miłecki <ra...@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 <ra...@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 <ra...@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 <ra...@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 <ra...@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

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