Using the MXS MCI driver with an eight bit capable eMMC results into the 'devinfo' message the interface uses '0' bits for data transfer: barebox:/ devinfo mxs_mci0 resources: num : 0 start : 0x80034000 size : 0x00002000 driver: mxs_mci bus: platform Interface Min. bus clock: 1476 Hz Max. bus clock: 48000000 Hz Current bus clock: 24000000 Hz Bus width: 0 bit The eight bit interface width is stored internally as value '2'. And a two bit '2' ends up into 0xfffffffe when used as an array index. Using an unsigned field instead fixes this issue: barebox:/ devinfo mxs_mci0 resources: num : 0 start : 0x80034000 size : 0x00002000 driver: mxs_mci bus: platform Interface Min. bus clock: 1476 Hz Max. bus clock: 48000000 Hz Current bus clock: 24000000 Hz Bus width: 8 bit Signed-off-by: Juergen Beisert <jbe@xxxxxxxxxxxxxx> diff --git a/drivers/mci/mxs.c b/drivers/mci/mxs.c index c15461c..9dee863 100644 --- a/drivers/mci/mxs.c +++ b/drivers/mci/mxs.c @@ -55,7 +55,7 @@ struct mxs_mci_host { unsigned f_min; unsigned f_max; #endif - int bus_width:2; /* 0 = 1 bit, 1 = 4 bit, 2 = 8 bit */ + unsigned bus_width:2; /* 0 = 1 bit, 1 = 4 bit, 2 = 8 bit */ }; #define to_mxs_mci(mxs) container_of(mxs, struct mxs_mci_host, host) -- Pengutronix e.K. | Juergen Beisert | Linux Solutions for Science and Industry | http://www.pengutronix.de/ | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox