Le 23/09/2020 à 18:08, Wolfram Sang a écrit :

On Wed, Sep 23, 2020 at 04:08:40PM +0200, nico.vince@gmail.com wrote:

quoted

From: Nicolas VINCENT <redacted>

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 <redacted>

Thanks!

Is someone able to identify a Fixes: tag I could add?

I'd suggest

Fixes: 61045dbe9d8d ("i2c: Add support for I2C bus on Freescale 
CPM1/CPM2 controllers")

Christophe

quoted

---
  drivers/i2c/busses/i2c-cpm.c | 3 +++
  1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-cpm.c b/drivers/i2c/busses/i2c-cpm.c
index 1213e1932ccb..24d584a1c9a7 100644
--- a/drivers/i2c/busses/i2c-cpm.c
+++ b/drivers/i2c/busses/i2c-cpm.c

@@ -65,6 +65,9 @@ struct i2c_ram {
  	char    res1[4];	/* Reserved */
  	ushort  rpbase;		/* Relocation pointer */
  	char    res2[2];	/* Reserved */
+	/* The following elements are only for CPM2 */
+	char    res3[4];	/* Reserved */
+	uint    sdmatmp;	/* Internal */
  };
  
  #define I2COM_START	0x80

-- 
2.17.1