On 10/11/2020 12:38, Tom Rini wrote: Hi Tom,
> On Sun, Nov 08, 2020 at 03:48:23PM +0000, André Przywara wrote: >> On 08/11/2020 14:59, Peter Robinson wrote: >> >> Hi, >> >>> On Sun, Nov 8, 2020 at 1:14 PM Andre Przywara <andre.przyw...@arm.com> >>> wrote: >>>> >>>> The eMMC standard describes the concept of boot partitions, consisting >>>> of two storage areas separate from the main user data partition. >>>> The Allwinner BootROM supports loading SPL/Boot0 from such a boot >>>> partition, if that is configured in the eMMC device [1]. >>>> >>>> To load U-Boot proper along with the SPL from there, currently this >>>> requires to enable CONFIG_SUPPORT_EMMC_BOOT, and this means that this >>>> build won't boot from the normal eMMC user partition anymore. >>>> Also the raw MMC sector offset needs to be adjusted manually, preventing >>>> a boot from an SD card. >>>> >>>> This series introduces automatic detection of eMMC boot partition boot. >>>> Patch 3/5 automates the raw MMC sector offset decision, allowing such >>>> a build to also boot from an SD card. >>>> Unfortunately the BootROM does not mark an eMMC boot partition boot >>>> differently from the normal eMMC user data partition boot, so patch 4/5 >>>> introduces a function that repeats the BootROM algorithm, so that the SPL >>>> comes to the same conclusion as the BootROM. This allows to build one >>>> single image that boots from everywhere: eMMC user data, eMMC boot, >>>> SD card, SPI flash. >>>> Patch 1/5 contains a bugfix that's needed in a later patch, patch 2/5 >>>> extends the generic spl_mmc_boot_mode() interface to make 4/5 feasible. >>>> >>>> Without enabling CONFIG_SUPPORT_EMMC_BOOT, the AArch64 SPL grows by >>>> 92 bytes, ARMv7 grows by 36 bytes. With enabling the feature, the size >>>> goes up by 444 bytes (AArch64) and 260 bytes (ARMv7). >>>> Even for AArch64 this is still 4.5 KB below the SPL limit, so patch 5/5 >>>> enables this new mechanism for some boards I could test this on. >>>> >>>> Please have a look and test this if you have a board with eMMC. >>>> I put installation instructions into the linux-sunxi Wiki: >>>> http://linux-sunxi.org/Bootable_eMMC >>> >>> It would probably be good to put that link in the local Allwinner docs >>> so it's easier for people to find. >> >> Yeah, actually as you mention it: >> There does not seem to be some generic README.sunxi file where this >> would belong to. >> >> Jagan: would it make sense to create one, and describe how to get U-Boot >> into the devices (SD card, eMMC, SPI flash, FEL)? That could move some >> parts of README.sunxi64 out of there, since they apply to all Allwinner >> devices. >> >> If people agree that this is the right thing to do, I would be happy to >> send a patch. > > Well, rST file in doc/boards/ and all of that, but, yes please. Ah, thanks for the pointer, looks good. Do we accept symlinks in the tree? There are quite some references to board/sunxi/README.sunxi64 out there. Or shall I keep a stub instead? Cheers, Andre
