Le 22/09/2020 à 11:04, nico.vi...@gmail.com a écrit :
From: Nicolas VINCENT <nicolas.vinc...@vossloh.com>

the i2c_ram structure is missing the sdmatmp field mentionned in
datasheet for MPC8272 at paragraph 36.5. With this field missing, the
hardware would write past the allocated memory done through
cpm_muram_alloc for the i2c_ram structure and land in memory allocated
for the buffers descriptors corrupting the cbd_bufaddr field. Since this
field is only set during setup(), the first i2c transaction would work
and the following would send data read from an arbitrary memory
location.

Signed-off-by: Nicolas VINCENT <nicolas.vinc...@vossloh.com>
---
  drivers/i2c/busses/i2c-cpm.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-cpm.c b/drivers/i2c/busses/i2c-cpm.c
index 1213e1932ccb..c5700addbf65 100644
--- a/drivers/i2c/busses/i2c-cpm.c
+++ b/drivers/i2c/busses/i2c-cpm.c
@@ -64,7 +64,8 @@ struct i2c_ram {
        uint    txtmp;          /* Internal */
        char    res1[4];        /* Reserved */
        ushort  rpbase;         /* Relocation pointer */
-       char    res2[2];        /* Reserved */
+       char    res2[6];        /* Reserved */
+       uint    sdmatmp;        /* Internal */

On CPM1, I2C param RAM has size 0x30 (offset 0x1c80-0x1caf)

Your change overlaps the miscellaneous area that contains CP Microcode Revision Number, ref MPC885 Reference Manual §18.7.3

  };
#define I2COM_START 0x80



Christophe

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