Hi Chris,
On 12.05.21 23:20, Chris Packham wrote:
On Wed, May 12, 2021 at 8:06 PM Stefan Roese sr@denx.de wrote:
On 12.05.21 09:59, Chris Packham wrote:
On Wed, May 12, 2021 at 7:18 PM Stefan Roese sr@denx.de wrote:
Currently, building U-Boot for x530 fails since the SPL image is too big.
Currently? It's working for me on master. Are there upcoming mvebu changes that push us over the limit?
Yes, I'm working on a pull request right now. Some enhancements to the SPI driver are most likely responsible for the code increase.
This patch reduces the SPL size by changing the following Kconfig options:
Enable CONFIG_SPL_TINY_MEMSET Disable CONFIG_SPI_FLASH_BAR
By disabling CONFIG_SPI_FLASH_BAR, the tiny SPI NOR framework can be used.
I've got a nagging feeling I needed CONFIG_SPI_FLASH_BAR for some reason. Possibly for some alternate part we were looking at, on the other hand it could also be from the db88f6820-amc board which I based the initial defconfig on.
Looking at what CONFIG_SPI_FLASH_BAR does I think we should be safe. We only fit 16MiB parts and aren't likely to start fitting bigger parts unless all the spi-nor vendors decide to stop making ones <16MiB.
Please note that there are better ways to handle the > 16MiB SPI NOR issue. E.g. by using 3 vs 4 byte commands and Serial Flash Discoverable Parameters (SFDP) parsing, which is supported in U-Boot since quite some time. I did not use CONFIG_SPI_FLASH_BAR for a longer time now IIRC.
I think (but am not sure) that the 4 byte command mode upsets the bootrom when booting from spi flash. On and off I've hit a problem on the db-88f6820-amc which does have a 32MiB flash fitted where the bootrom can't fetch the first boot stage on reboot after booting linux (for some kernel versions). Power cycling resolves the problem. I think this might be because the bootrom only speaks the 3 byte protocol and once the chip is put into 4 byte mode the bootrom lacks the ability to change back. None of this affects the x530 so there is no problem with this change. I'm just putting this out there for future mailing list readers.
Yes, this is known issue. Or it was a known issue. Newer version support the stateless 4-byte opcodes, which don't configure the SPI NOR into 4-byte mode. This resolves this problem with the bootrom AFAIR.
Thanks, Stefan