Re: [PATCH 1/2] nvmem: stm32: add warning when upper OTPs are updated

From: Patrick DELAUNAY
Date: Fri Oct 14 2022 - 11:44:32 EST


Hi,

On 10/14/22 17:04, Patrick Delaunay wrote:
As the upper OTPs are ECC protected, they support only one 32 bits word
programming.
For a second modification of this word, these ECC become invalid and
this OTP will be no more accessible, the shadowed value is invalid.

This patch adds a warning to indicate an upper OTP update, because this
operation is dangerous as OTP is not locked by the driver after the first
update to avoid a second update.

Signed-off-by: Patrick Delaunay <patrick.delaunay@xxxxxxxxxxx>
---

drivers/nvmem/stm32-romem.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
index 354be526897f..e3c3c333b5d1 100644
--- a/drivers/nvmem/stm32-romem.c
+++ b/drivers/nvmem/stm32-romem.c
@@ -133,6 +133,9 @@ static int stm32_bsec_write(void *context, unsigned int offset, void *buf,
}
}
+ if (offset + bytes >= priv->lower * 4)


Here I miss a dependency for "priv->lower" with a other preliminary patch for STM32MP13x support.


+ dev_warn(dev, "Update of upper OTPs with ECC protection (word programming, only once)\n");
+
return 0;
}


Sorry,

I will sent a V2 soon


Patrick