target/linux/generic/backport-6.1/808-v6.2-0002-nvmem-stm32-add-warning-when-upper-OTPs-are-updated.patch

   1 From d61784e6410f3df2028e6eb91b06ffed37a660e0 Mon Sep 17 00:00:00 2001
   2 From: Patrick Delaunay <patrick.delaunay@foss.st.com>
   3 Date: Fri, 18 Nov 2022 06:39:21 +0000
   4 Subject: [PATCH] nvmem: stm32: add warning when upper OTPs are updated
   5
   6 As the upper OTPs are ECC protected, they support only one 32 bits word
   7 programming.
   8 For a second modification of this word, these ECC become invalid and
   9 this OTP will be no more accessible, the shadowed value is invalid.
  10
  11 This patch adds a warning to indicate an upper OTP update, because this
  12 operation is dangerous as OTP is not locked by the driver after the first
  13 update to avoid a second update.
  14
  15 Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
  16 Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  17 Link: https://lore.kernel.org/r/20221118063932.6418-3-srinivas.kandagatla@linaro.org
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  19 ---
  20  drivers/nvmem/stm32-romem.c | 3 +++
  21  1 file changed, 3 insertions(+)
  22
  23 --- a/drivers/nvmem/stm32-romem.c
  24 +++ b/drivers/nvmem/stm32-romem.c
  25 @@ -132,6 +132,9 @@ static int stm32_bsec_write(void *contex
  26                 }
  27         }
  28
  29 +       if (offset + bytes >= priv->lower * 4)
  30 +               dev_warn(dev, "Update of upper OTPs with ECC protection (word programming, only once)\n");
  31 +
  32         return 0;
  33  }
  34