@@ -3,11 +3,13 @@
* Copyright (C) 2020 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
*/
+#include <linux/crc32.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of_reserved_mem.h>
#include <linux/platform_device.h>
+#include <linux/slab.h>
struct rmem {
struct device *dev;
@@ -15,6 +17,18 @@ struct rmem {
struct reserved_mem *mem;
};
+struct rmem_match_data {
+ int (*checksum)(struct rmem *priv);
+};
+
+struct __packed rmem_eyeq5_header {
+ u32 magic;
+ u32 version;
+ u32 size;
+};
+
+#define RMEM_EYEQ5_MAGIC ((u32)0xDABBAD00)
+
static int rmem_read(void *context, unsigned int offset,
void *val, size_t bytes)
{
@@ -47,10 +61,66 @@ static int rmem_read(void *context, unsigned int offset,
return 0;
}
+static int rmem_eyeq5_checksum(struct rmem *priv)
+{
+ struct rmem_eyeq5_header header;
+ void *buf __free(kfree) = NULL;
+ u32 computed_crc, *target_crc;
+ size_t data_size;
+ int ret;
+
+ ret = rmem_read(priv, 0, &header, sizeof(header));
+ if (ret)
+ return ret;
+
+ if (header.magic != RMEM_EYEQ5_MAGIC)
+ return -EINVAL;
+
+ /*
+ * Avoid massive kmalloc() if header read is invalid;
+ * the check would be done by the next rmem_read() anyway.
+ */
+ if (header.size > priv->mem->size)
+ return -EINVAL;
+
+ /*
+ * 0 +-------------------+
+ * | Header (12 bytes) | \
+ * +-------------------+ |
+ * | | | data to be CRCed
+ * | ... | |
+ * | | /
+ * data_size +-------------------+
+ * | CRC (4 bytes) |
+ * header.size +-------------------+
+ */
+
+ buf = kmalloc(header.size, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ ret = rmem_read(priv, 0, buf, header.size);
+ if (ret)
+ return ret;
+
+ data_size = header.size - sizeof(*target_crc);
+ target_crc = buf + data_size;
+ computed_crc = crc32(U32_MAX, buf, data_size) ^ U32_MAX;
+
+ if (computed_crc == *target_crc)
+ return 0;
+
+ dev_err(priv->dev,
+ "checksum failed: computed %#x, expected %#x, header (%#x, %#x, %#x)\n",
+ computed_crc, *target_crc, header.magic, header.version, header.size);
+ return -EINVAL;
+}
+
static int rmem_probe(struct platform_device *pdev)
{
struct nvmem_config config = { };
struct device *dev = &pdev->dev;
+ const struct rmem_match_data *match_data = device_get_match_data(dev);
struct reserved_mem *mem;
struct rmem *priv;
@@ -73,10 +143,21 @@ static int rmem_probe(struct platform_device *pdev)
config.size = mem->size;
config.reg_read = rmem_read;
+ if (match_data && match_data->checksum) {
+ int ret = match_data->checksum(priv);
+ if (ret)
+ return ret;
+ }
+
return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
}
+static const struct rmem_match_data rmem_eyeq5_match_data = {
+ .checksum = rmem_eyeq5_checksum,
+};
+
static const struct of_device_id rmem_match[] = {
+ { .compatible = "mobileye,eyeq5-bootloader-config", .data = &rmem_eyeq5_match_data },
{ .compatible = "nvmem-rmem", },
{ /* sentinel */ },
};
Mobileye EyeQ5 has a non-volatile memory region which gets used to store MAC addresses. Its format includes a prefix 12-byte header and a suffix 4-byte CRC. Add an optional ->checksum() callback inside match data; it runs CRC32 onto the content. Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com> --- drivers/nvmem/rmem.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+)