Hi,
I'm currently working on a custom board with an at91sam9g45 : I followed the instruction in README.atmel_mci. In U-boot, if I use the command mmcinfo, the system hang. The uSD is working correctly with at91bootstrap and linux. In U-boot everything seems fine, the card exchange a few command and response, and then freeze on the command 55 51 (the first command that will receive some data on DAT0 ) :
U-Boot> mmcinfo mci: bus_hz is 133333333, setting clock 150000 Hz, block size 512 mci: setting clock 260416 Hz, block size 512 mci: bus_hz is 133333333, setting clock 0 Hz, block size 512 mci: setting clock 260416 Hz, block size 512 mci: bus_hz is 133333333, setting clock 260416 Hz, block size 512 mci: setting clock 260416 Hz, block size 512 gen_atmel_mci: CMDR 00001000 ( 0) ARGR 00000000 (SR: 00000000) DEBUG gen_atmel_mci: CMDR 00001048 ( 8) ARGR 000001aa (SR: 00000000) DEBUG gen_atmel_mci: CMDR 00001077 (55) ARGR 00000000 (SR: 00000000) DEBUG gen_atmel_mci: CMDR 00001069 (41) ARGR 40300000 (SR: 00000000) DEBUG gen_atmel_mci: CMDR 00001077 (55) ARGR 00000000 (SR: 00000000) DEBUG gen_atmel_mci: CMDR 00001069 (41) ARGR 40300000 (SR: 00000000) DEBUG gen_atmel_mci: CMDR 00001082 ( 2) ARGR 00000000 (SR: 00000000) DEBUG gen_atmel_mci: CMDR 00001043 ( 3) ARGR 00000000 (SR: 00000000) DEBUG gen_atmel_mci: CMDR 00001089 ( 9) ARGR 88f70000 (SR: 00000000) DEBUG gen_atmel_mci: CMDR 000010c7 ( 7) ARGR 88f70000 (SR: 00000000) DEBUG gen_atmel_mci: CMDR 00001077 (55) ARGR 88f70000 (SR: 00000000) DEBUG gen_atmel_mci: CMDR 00051073 (51) ARGR 00000000 (SR: 00000000) DEBUG Read Data: 00000000: 02 25 00 00 00 00 00 00 .%...... filling rest of block...
then everything freeze ... But if I add some printf to debug , just after the mci_data_op=mci_data_read() in gen_atmel_mci, then everything is OK and I can now use the uSD without any problem. Here is where I add the printf, so uSD is correctly handled :
diff -crbN u-boot-2010.09.orig/drivers/mmc/gen_atmel_mci.c u-boot-2010.09/drivers/mmc/gen_atmel_mci.c *** u-boot-2010.09.orig/drivers/mmc/gen_atmel_mci.c 2010-09-28 23:20:55.000000000 +0200 --- u-boot-2010.09/drivers/mmc/gen_atmel_mci.c 2010-12-04 17:52:59.092770689 +0100 *************** *** 252,257 **** --- 252,258 ---- while (!status && word_count < (sys_blocksize / 4)) { status = mci_data_op(mci, &dummy, error_flags); + printf("status=%x\n",status); word_count++; } if (status) {
The result (status) from mci_data_op (=mci_data_read()) is always 0. It's a bit like if there was a timeout not correctly handled. I had the same sympton on different uSD. Actually U-boot is started by At91Bootstrap, so some HMCI register are probably not at there default value ? Any advice to investigate further ?
best regards,
Eric Cariat