Hi Jagan, On Wed, Oct 29, 2014 at 2:16 PM, Jagan Teki <jagannadh.t...@gmail.com> wrote: > Hi Bin, > > This looks odd to me - supporting array slow without support on fast read. > Please check the datasheets, and as per as my knowledge/experience it > should support both.
It is not the flash but the controller only supports array slow read. Yes, odd controller indeed, but supporting fast read needs a dummy cycle which I believe requires the controller to know this fact. > Note: I have tested SST25WF080 with fast read couple of times. It's no surprise. The spi controller you tested should support both fast read and slow read. >>> See below code for more understanding: >>> /* Look for the fastest read cmd */ >>> cmd = fls(params->e_rd_cmd & flash->spi->op_mode_rx); >>> if (cmd) { >>> cmd = spi_read_cmds_array[cmd - 1]; >>> flash->read_cmd = cmd; >>> } else { >>> /* Go for default supported read cmd */ >>> flash->read_cmd = CMD_READ_ARRAY_FAST; >>> } >> >> Yes, I understand the logic here as well. That's why I asked in my >> previous email >> >>> +ARRAY_FAST = 1 << 5, >> >> Whether this one (fast array read) should become 1 << 5. Also I >> started to question whether it is OK to group these command together >> like below >> >> #define RD_EXTN (ARRAY_SLOW | DUAL_OUTPUT_FAST | DUAL_IO_FAST) >> #define RD_FULL (RD_EXTN | QUAD_OUTPUT_FAST | QUAD_IO_FAST) >> >> Again I need cross check flash datasheets. > > Please do - for all [if possible] > OK, will do in v2 patch. Thanks for the comments. Regards, Bin _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot