On 2014-08-05 09:20, Hannes Petermaier wrote:
hi folks,
i am actually trying to enable the "enhanced data area" on an 4GB emmc device, this i've done successfully with the linux mmc-utils and the card has after this "partitioning" 2GB user-partition.
Linux kernel deals correctly with the card.
U-Boot doesn't:
" MMC: block number 0x301 exceeds max(0x0) spl: mmc blk read err - 0 ### ERROR ### Please RESET the board ### "
So i debugged around and found the capacity-calculation, which i don't fully understand. " if (mmc->high_capacity) { csize = (mmc->csd[1] & 0x3f) << 16 | (mmc->csd[2] & 0xffff0000) >> 16; cmult = 8; } else { csize = (mmc->csd[1] & 0x3ff) << 2 | (mmc->csd[2] & 0xc0000000) >> 30; cmult = (mmc->csd[2] & 0x00038000) >> 15; } " The else path does for my opinion the right calculation according the mmc-specification, the "high_capacity" path i do not understand at all, neither i found some specification for this.
In fact my 4GB card (with 2GB enhanced area) works only with "the else" path. my csd Registers:
MMC-card dection: ocr : 0xc0ff8080 csd[0] : 0xd04f0132 csd[1] : 0x0f5a13ff csd[2] : 0xffffffe7 csd[3] : 0x8a4000f1 c_size : 0x00000000003fffff c_mult : 0x0000000000000008
U-Boot (BuR V2.0)# mmc info Device: OMAP SD/MMC Manufacturer ID: fe OEM: 14e Name: MMC04 Tran Speed: 52000000 Rd Block Len: 512 MMC version 4.41 High Capacity: Yes Capacity: 4 TiB Bus Width: 1-bit
any ideas ?
best regards, Hannes
I've digged a bit deeper and found an (for me, as newbie in this) interesting webpage:
http://www.hjreggel.net/cardspeed/special-sd.html
there i've found the key to understand the "high_capacity" path: "...In CSD Version 2.0, the C_SIZE field was extended to 22 bit. The C_SIZE_MULT was dropped, assuming a preset multiplier of 2^10 . The READ_BL_LEN was kept, but the only value allowed is 9, indicating a block length of 512 bytes."
So the code should be as following:
- if (mmc->high_capacity) { + if (mmc->high_capacity && mmc->read_bl_len == MMC_MAX_BLOCK_LEN) {
i'am correct in my thinking ? please some comment. if yes - i will format a patch for this
best regards, Hannes