Hi Jagan,
On Tue, Dec 9, 2014 at 2:04 AM, Jagan Teki jagannadh.teki@gmail.com wrote:
Hi Bin,
On 1 November 2014 at 14:23, Bin Meng bmeng.cn@gmail.com wrote:
Currently if SST flash advertises SST_WP flag in the params table the word program command (ADh) with auto address increment will be used for the flash write op. However some SPI controllers do not support the word program command (like the Intel ICH 7), the byte programm command (02h) has to be used.
A new TX operation mode SPI_OPM_TX_BP is introduced for such SPI controller to use byte program op for SST flash.
We have SST_WP which is word program - for specific flash's (not for controller specific at-least from params data)
Which is this SST_BP relies for ? controller or specific flash ?
SST_BP is flash specific. In current flash params table, I checked every flash datasheet and found that when an SST flash supports WP, it also supports BP. I believe the WP and BP are companion commands. When an SST flash does not support BP/WP, it supports the page program (02h) which uses the same command code as BP. And the page program (02h) is the command selected by U-Boot for SST flashes which do not have SST_WP flag.
However some controllers do not support WP, so that we need the SST_BP flag to let U-Boot selects BP for such controllers, which is what my patch tries to fix.
[snip]
Regards, Bin