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[v2,2/3] nvmem: stm32: add warning when upper OTPs are updated

Message ID 20221017174953.v2.2.Ifa806ff30d7c669ba9a3df9c6b64698a2dcc073a@changeid (mailing list archive)
State New, archived
Headers show
Series nvmem: stm32: several minor improvements | expand

Commit Message

Patrick Delaunay Oct. 17, 2022, 3:49 p.m. UTC 
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@foss.st.com>
---

(no changes since v1)

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

diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
index d93baee01d7b..bb8aa72ba2f9 100644
--- a/drivers/nvmem/stm32-romem.c
+++ b/drivers/nvmem/stm32-romem.c
@@ -132,6 +132,9 @@  static int stm32_bsec_write(void *context, unsigned int offset, void *buf,
 		}
 	}
 
+	if (offset + bytes >= priv->lower * 4)
+		dev_warn(dev, "Update of upper OTPs with ECC protection (word programming, only once)\n");
+
 	return 0;
 }