Author: hailfinger Date: 2009-05-26 23:25:08 +0200 (Tue, 26 May 2009) New Revision: 549
Modified: trunk/ichspi.c Log: Use REMS instead of RES in the ICH SPI default opcode table.
RES is Read Electronic Signature (1 Byte, identical for different chips) REMS is Read Electronic Manufacturer Signature (2 Bytes, mostly unique) RDID is Read JEDEC ID (3 bytes, unique)
Of the chips which don't support RDID, a sizable portion supports REMS which gives us both a manufacturer ID and a device ID. This is clearly superior to having only a device ID (the RES case) which has multiple documented collisions.
The RES/REMS problem is aggravated by inconsistent naming in vendor data sheets. What's in a name? Considering that we have 1-byte IDs, 2-byte IDs and 3+byte IDs with varying names but mostly consistent opcodes, it makes sense to set our own standard about how the opcodes are called.
The best way forward would be to have the ICH SPI driver reprogram the opcode menu on the fly if the opcode menu doesn't contain the requested opcode and the opcode menu is not locked. Until that happens, this patch improves detection accuracy by a factor of 256 for some chips.
Signed-off-by: Carl-Daniel Hailfinger c-d.hailfinger.devel.2006@gmx.net
Tested-by: Uwe Hermann with the flash chip "SST SST25VF040.REMS".
Acked-by: Ronald G. Minnich rminnich@gmail.com
Modified: trunk/ichspi.c =================================================================== --- trunk/ichspi.c 2009-05-26 09:48:28 UTC (rev 548) +++ trunk/ichspi.c 2009-05-26 21:25:08 UTC (rev 549) @@ -179,7 +179,7 @@ {JEDEC_READ, SPI_OPCODE_TYPE_READ_WITH_ADDRESS, 0}, // Read Data {JEDEC_BE_D8, SPI_OPCODE_TYPE_WRITE_WITH_ADDRESS, 1}, // Erase Sector {JEDEC_RDSR, SPI_OPCODE_TYPE_READ_NO_ADDRESS, 0}, // Read Device Status Reg - {JEDEC_RES, SPI_OPCODE_TYPE_READ_WITH_ADDRESS, 0}, // Resume Deep Power-Down + {JEDEC_REMS, SPI_OPCODE_TYPE_READ_WITH_ADDRESS, 0}, // Read Electronic Manufacturer Signature {JEDEC_WRSR, SPI_OPCODE_TYPE_WRITE_NO_ADDRESS, 1}, // Write Status Register {JEDEC_RDID, SPI_OPCODE_TYPE_READ_NO_ADDRESS, 0}, // Read JDEC ID {JEDEC_CE_C7, SPI_OPCODE_TYPE_WRITE_NO_ADDRESS, 1}, // Bulk erase