This implements write support to imx-ocotp-ele. By default only the
shadow values are written which is harmless and nearly useless (as the
ROM doesn't seem use these values). Real write support is enabled by
setting imx_ocotp0.permanent_write_enable to true. A big warning is
printed and the next write access to /dev/imx_ocotp will then really
burn fuses.
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
drivers/nvmem/imx-ocotp-ele.c | 36 ++++++++++++++++++++++++++++++++++-
1 file changed, 35 insertions(+), 1 deletion(-)
diff --git a/drivers/nvmem/imx-ocotp-ele.c b/drivers/nvmem/imx-ocotp-ele.c
index 9708d3f4bb..b25ab32fea 100644
--- a/drivers/nvmem/imx-ocotp-ele.c
+++ b/drivers/nvmem/imx-ocotp-ele.c
@@ -41,6 +41,7 @@ struct imx_ocotp_priv {
void __iomem *base;
const struct ocotp_devtype_data *data;
struct regmap_config map_config;
+ int permanent_write_enable;
};
static enum fuse_type imx_ocotp_fuse_type(struct imx_ocotp_priv *priv, u32 index)
@@ -92,6 +93,22 @@ static int imx_ocotp_reg_read(void *context, unsigned int offset, unsigned int *
return 0;
};
+static int imx_ocotp_reg_write(void *context, unsigned int offset, unsigned int val)
+{
+ struct imx_ocotp_priv *priv = context;
+ u32 index;
+ int ret;
+
+ index = offset >> 2;
+
+ if (priv->permanent_write_enable)
+ ret = ele_write_fuse(index, val, false, NULL);
+ else
+ ret = ele_write_shadow_fuse(index, val, NULL);
+
+ return ret;
+}
+
static int imx_ocotp_cell_pp(void *context, const char *id, unsigned int offset,
void *data, size_t bytes)
{
@@ -116,6 +133,7 @@ static int imx_ocotp_cell_pp(void *context, const char *id, unsigned int offset,
}
static struct regmap_bus imx_ocotp_regmap_bus = {
+ .reg_write = imx_ocotp_reg_write,
.reg_read = imx_ocotp_reg_read,
};
@@ -132,6 +150,18 @@ static void imx_ocotp_set_unique_machine_id(struct imx_ocotp_priv *priv)
machine_id_set_hashable(unique_id_parts, sizeof(unique_id_parts));
}
+static int permanent_write_enable_set(struct param_d *param, void *ctx)
+{
+ struct imx_ocotp_priv *priv = ctx;
+
+ if (priv->permanent_write_enable) {
+ dev_warn(priv->dev, "Enabling permanent write on fuses.\n");
+ dev_warn(priv->dev, "Writing fuses may damage your device. Be careful!\n");
+ }
+
+ return 0;
+}
+
static int imx_ele_ocotp_probe(struct device *dev)
{
struct imx_ocotp_priv *priv;
@@ -141,6 +171,7 @@ static int imx_ele_ocotp_probe(struct device *dev)
int ret;
priv = xzalloc(sizeof(*priv));
+ priv->dev = dev;
ret = dev_get_drvdata(dev, (const void **)&data);
if (ret)
@@ -165,11 +196,14 @@ static int imx_ele_ocotp_probe(struct device *dev)
if (IS_ENABLED(CONFIG_MACHINE_ID))
imx_ocotp_set_unique_machine_id(priv);
- nvmem = nvmem_regmap_register_with_pp(priv->map, "imx-ocotp",
+ nvmem = nvmem_regmap_register_with_pp(priv->map, "imx_ocotp",
imx_ocotp_cell_pp);
if (IS_ERR(nvmem))
return PTR_ERR(nvmem);
+ dev_add_param_bool(nvmem_device_get_device(nvmem), "permanent_write_enable",
+ permanent_write_enable_set, NULL, &priv->permanent_write_enable, priv);
+
return 0;
}
--
2.39.2
