Hi,
On Sun, Aug 11, 2013 at 3:42 PM, thomas.langer@lantiq.com wrote:
Hi Jagan,
+/* Definitions of the flash commands - Flash insts in ascending order */ +#define ZYNQ_QSPI_FLASH_INST_WRSR 0x01 /* Write status register */ +#define ZYNQ_QSPI_FLASH_INST_PP 0x02 /* Page program */ +#define ZYNQ_QSPI_FLASH_INST_WRDS 0x04 /* Write disable */ +#define ZYNQ_QSPI_FLASH_INST_RDSR1 0x05 /* Read status register 1 */ +#define ZYNQ_QSPI_FLASH_INST_WREN 0x06 /* Write enable */ +#define ZYNQ_QSPI_FLASH_INST_AFR 0x0B /* Fast read data bytes */ +#define ZYNQ_QSPI_FLASH_INST_BE_4K 0x20 /* Erase 4KiB block */ +#define ZYNQ_QSPI_FLASH_INST_RDSR2 0x35 /* Read status register 2 */ +#define ZYNQ_QSPI_FLASH_INST_BE_32K 0x52 /* Erase 32KiB block */ +#define ZYNQ_QSPI_FLASH_INST_RDID 0x9F /* Read JEDEC ID */ +#define ZYNQ_QSPI_FLASH_INST_SE 0xD8 /* Sector erase (usually 64KB)*/
As I have written some time ago, I think it is a bad idea to parse the flash commands in the spi driver! The flash driver, who wants to write these commands and should know the details, which parts of the message needs to be send as dual/quad transfer, should provide this information to the spi driver (probably as flags for spi_xfer())
A first idea for the flags:
- the X refers to different numbers, as required by the flash (depending on the
addressing mode (3/4 byte) or if the address is already sent as DUAL/QUAD) SPI_XFER_X_DUAL SPI_XFER_X_QUAD
So having 0-5 for X should be enough to support all flashes -> 0 if the command is already in DUAL/QUAD mode -> 5 for command + 4byte address (I am not sure about dummy bytes on read)
So for example: switch to dual transfer after first byte: SPI_XFER_1_DUAL switch to QUAD transfer after 4 bytes (e.g. 3byte address): SPI_XFER_4_QUAD
Then only the flash driver needs to know these requirements, depending on manufacturer and chip type, and the spi driver just "reacts" on the flags. Otherwise this driver has to be extended each time a new command is added to the flash driver (as you did in some later patches!)
Thanks for your comments. Yes, I agreed controller doesn't require to know about the flash instructions. I am planning to remove these setup on next coming patch versions.
-- Thanks, Jagan.