| Message ID | 1423672220-13744-1-git-send-email-bigeasy@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Sebastian Andrzej Siewior <bigeasy <at> linutronix.de> writes:
> So my question is basically, is it okay to read from this partition?
You can read from RPMB only after sending RPMB command (25) according to
RPMB protocol. So the RPMB is not "first class" partition.
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diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index 7466ce098e60..52faf8f4f45f 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -512,6 +512,7 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd) /* * RPMB regions are defined in multiples of 128K. */ +#if 0 card->ext_csd.raw_rpmb_size_mult = ext_csd[EXT_CSD_RPMB_MULT]; if (ext_csd[EXT_CSD_RPMB_MULT] && mmc_host_cmd23(card->host)) { mmc_part_add(card, ext_csd[EXT_CSD_RPMB_MULT] << 17, @@ -519,6 +520,7 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd) "rpmb", 0, false, MMC_BLK_DATA_AREA_RPMB); } +#endif } card->ext_csd.raw_erased_mem_count = ext_csd[EXT_CSD_ERASED_MEM_CONT];
I have here a SK-Hynix eMMC media which is eMMC 5.0 compatible (according to the manual). I read / write the media and haven't noticed anything odd. Then I tried to boot using systemd :) Systemd needs to touch everything and so it tried to read from the rpmb partition. The results were not good. The MMC core sends first CMD18 which ends with -110 after a few secs. CMD17 ends with the same error "immediately". Looking into the "JEDEC STANDARD Embedded Multi-Media Card (eMMC) Electrical Standard (5.01)" / JESD84-B50.1" I read the following in "6.2.2 Command restrictions": |RPMB Partition |o Only commands of classes Class0, Class2 and Class4 are admitted. Still usage of any | other command than CMD0, CMD6, CMD8, CMD12, CMD13, CMD15 or commands | defined in 6.6.25 shall be considered as illegal one. CMD17 + CMD18 are part of Class 2 (and therefore legal) however the later enumeration commands excludes CMD17 + 18 from beeing legal. So my question is basically, is it okay to read from this partition? Here is output of "dd if=/dev/mmcblk0rpmb of=/dev/null count=1" Single read only: [ 625.881087] mmc0: starting CMD6 arg 03b30301 flags 0000049d [ 625.888813] mmc0: req done (CMD6): 0: 00000900 00000000 00000000 00000000 [ 625.895659] mmc0: starting CMD13 arg 00010000 flags 00000195 [ 625.901360] mmc0: req done (CMD13): 0: 00000900 00000000 00000000 00000000 [ 625.908255] mmc0: starting CMD17 arg 00000000 flags 000000b5 [ 625.913934] mmc0: blksz 512 blocks 1 flags 00000200 tsac 150 ms nsac 1000 [ 625.921114] mmc0: req done (CMD17): -110: 00000000 00000000 00000000 00000000 [ 625.928253] mmc0: 0 bytes transferred: 0 [ 625.932547] mmc0: starting CMD13 arg 00010000 flags 00000195 [ 625.938228] mmc0: req done (CMD13): 0: 00400900 00000000 00000000 00000000 [ 625.945129] mmcblk0rpmb: timed out sending r/w cmd command, card status 0x400900 Multi read: [ 14.257869] mmc0: starting CMD6 arg 03b30301 flags 0000049d [ 14.265570] mmc0: req done (CMD6): 0: 00000900 00000000 00000000 00000000 [ 14.272398] mmc0: starting CMD13 arg 00010000 flags 00000195 [ 14.278083] mmc0: req done (CMD13): 0: 00000900 00000000 00000000 00000000 [ 14.284997] <mmc0: starting CMD23 arg 00000020 flags 00000015> [ 14.290846] mmc0: starting CMD18 arg 00000000 flags 000000b5 [ 14.296508] mmc0: blksz 512 blocks 32 flags 00000200 tsac 150 ms nsac 1000 [ 14.303742] mmc0: CMD12 arg 00000000 flags 00000095 [ 19.737209] mmc0: req done <CMD23>: 0: 00000000 00000000 00000000 00000000 [ 19.744089] mmc0: req done (CMD18): 0: 00000900 00000000 00000000 00000000 [ 19.750964] mmc0: 0 bytes transferred: -110 [ 19.755495] mmc0: (CMD12): 0: 00000b00 00000000 00000000 00000000 [ 19.761963] mmc0: starting CMD13 arg 00010000 flags 00000195 [ 19.767646] mmc0: req done (CMD13): 0: 00000900 00000000 00000000 00000000 [ 19.774558] mmcblk0rpmb: error -110 transferring data, sector 0, nr 32, cmd response 0x900, card status 0xb00 and then, there is this dead mode: [ 44.055345] mmc0: starting CMD6 arg 03b30301 flags 0000049d [ 44.063039] mmc0: req done (CMD6): 0: 00000900 00000000 00000000 00000000 [ 44.069849] mmc0: starting CMD13 arg 00010000 flags 00000195 [ 44.075559] mmc0: req done (CMD13): 0: 00000900 00000000 00000000 00000000 [ 44.082460] mmc0: Card stuck in programming state! __mmc_switch [ 44.088386] blk_update_request: I/O error, dev mmcblk0rpmb, sector 0 mostly the same thing as above except that it dies within CMD13. After that it does not boot from eMMC and the eMMC looks dead if I boot differently. A few minutes powerless and everything is back to normal. At this point I am not sure if access to the rpmb is a problem or a problem at surface and I should be chasing something else. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/mmc/core/mmc.c | 2 ++ 1 file changed, 2 insertions(+)