adafruit-mirror/zephyr
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 9

drivers: i3c: cdns: handle variable length ccc with m0 err

Browse source 
The CDNS will report a M0 error if the data length is not what
it expects, but certain CCCs can have a variable length such as
GETMXDS and GETCAPS. This sets it up to ignore the M0 error if
it sees that ccc was GETMXDS or GETCAPS.

Signed-off-by: Ryan McClelland <ryanmcclelland@meta.com>
This commit is contained in:
Ryan McClelland 2024-04-22 16:20:39 -07:00 committed by Carles Cufí
parent bb66b7b870
commit c75783219f
1 changed files with 34 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

35
drivers/i3c/i3c_cdns.c
View file

@ -1350,9 +1350,42 @@ static void cdns_i3c_complete_transfer(const struct device *dev)
}
break;
case CMDR_M0_ERROR: {
uint8_t ccc = data->xfer.cmds[i].cmd1 & 0xFF;
/*
* The M0 is an illegally formatted CCC. i.e. the Controller
* receives 1 byte instead of 2 with the GETMWL CCC. This can
* be problematic for CCCs that can have variable length such
* as GETMXDS and GETCAPS. Verify the number of bytes received matches
* what's expected from the specification and ignore the error. The IP will
* still retramsit the same CCC and theres nothing that can be done to
* prevent this. It it still up to the application to read `num_xfer` to
* determine the number of bytes returned.
*/
if (ccc == I3C_CCC_GETMXDS) {
/*
* Whether GETMXDS format 1 and format 2 can't be known ahead of
* time which will be returned.
*/
if ((*data->xfer.cmds[i].num_xfer !=
sizeof(((union i3c_ccc_getmxds *)0)->fmt1)) &&
(*data->xfer.cmds[i].num_xfer !=
sizeof(((union i3c_ccc_getmxds *)0)->fmt2))) {
ret = -EIO;
}
} else if (ccc == I3C_CCC_GETCAPS) {
/* GETCAPS can only return 1-4 bytes */
if (*data->xfer.cmds[i].num_xfer > sizeof(union i3c_ccc_getcaps)) {
ret = -EIO;
}
} else {
ret = -EIO;
}
break;
}
case CMDR_DDR_PREAMBLE_ERROR:
case CMDR_DDR_PARITY_ERROR:
case CMDR_M0_ERROR:
case CMDR_M1_ERROR:
case CMDR_M2_ERROR:
case CMDR_NACK_RESP: