________________________________________
From: Philip Rakity
Sent: Thursday, March 04, 2010 9:01 PM
To: [email protected]
Cc: Lennert Buijtenhek; Nicolas Pitre
Subject: Bug in mmc.c == stops eMMC toshiba from working - sector check not
good
Folks
Toshiba part eMMC -- 2GB fails in standard linux. The part is NOT sector
addressable yet linux tries to do this. See incorrect code below in mmc.c and
notes below
The tosbiha part HAS ext_csd.sectors
from mmc.c
static int mmc_read_ext_csd(struct mmc_card *card)
if (card->ext_csd.rev >= 2) {
card->ext_csd.sectors =
ext_csd[EXT_CSD_SEC_CNT + 0] << 0 |
ext_csd[EXT_CSD_SEC_CNT + 1] << 8 |
ext_csd[EXT_CSD_SEC_CNT + 2] << 16 |
ext_csd[EXT_CSD_SEC_CNT + 3] << 24;
if (card->ext_csd.sectors)
mmc_card_set_blockaddr(card);
}
when set cause code in block.c to not make address byte oriented
static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
.....
brq.cmd.arg = blk_rq_pos(req);
if (!mmc_card_blockaddr(card))
brq.cmd.arg <<= 9;
The Toshiba card HAS ext_csd.sectors even though the CMD1 response says it does
not do sector addressing -- returning the ocr register.
The Simplified Physical Layer Spec defines for the OCR register
bit 29 as reserved and bit 30 as CCS -- High Capacity Card
The JEDEC Standard No. 84-A43 defines the OCR register Table 31 (OCR Register)
bits 29 and 30
00 == byte mode
10 == sector mode
I can change the code to save the ocr on the CMD1 and use the value of bit 30
to select Sector Mode IF there is a sector table.
Are there any other thoughts ?
regards,
Philip
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