On 13.08.2015 12:50, Hou Zhiqiang wrote:
-----Original Message----- From: Siva Durga Prasad Paladugu [mailto:siva.durga.paladugu@xilinx.com] Sent: 2015年8月13日 17:18 To: Hou Zhiqiang-B48286; u-boot@lists.denx.de; jteki@openedev.com Cc: Sun York-R58495; Hu Mingkai-B21284; nofooter Subject: RE: [PATCH V6] sf: Turn SPI flash chip into 3-Byte address mode
Hi Zhejiang/Jagan,
I think it would be good to extend this further to support 4-byte addressing in u-boot also. This would be based on the driver, We can get the data that whether the controller supports 4-byte or not from the driver level(through slave struct) and enable 4 byte addressing here based on that.
That is a long way, and I don't think it is necessary for U-Boot. The U-Boot work well using BAR to address more than 16MiB flash. This patch focus on the address mode issue when warm boot up base on the BAR address mode.
Please correct me if I'm wrong, but AFAIU this BAR thing (CONFIG_SPI_FLASH_BAR) doesn't support to address e.g. a 64MiB SPI flash contiguously. Only 16MiB areas. So for example its not possible to put UBI/UBIFS in such a big partition.
I have to support Siva here. We really should try to support this 4-byte mode correctly. This can't be too hard.
Thanks, Stefan