-----Original Message----- From: Trent Piepho tpiepho@impinj.com Sent: Monday, July 16, 2018 3:45 PM To: Henry Beberman Henry.Beberman@microsoft.com; u- boot@lists.denx.de Cc: trini@konsulko.com; fabio.estevam@nxp.com Subject: Re: [U-Boot] [PATCH 01/11] imx: Add bootcmd to load and run UEFI from mmc
On Mon, 2018-07-16 at 22:28 +0000, Henry Beberman wrote:
Hi Trent,
-----Original Message----- From: Trent Piepho tpiepho@impinj.com Sent: Monday, July 16, 2018 10:17 AM To: Henry Beberman Henry.Beberman@microsoft.com; u- boot@lists.denx.de Cc: trini@konsulko.com; fabio.estevam@nxp.com Subject: Re: [U-Boot] [PATCH 01/11] imx: Add bootcmd to load and run UEFI from mmc
On Sat, 2018-07-14 at 00:11 +0000, Henry Beberman wrote:
From: Henry Beberman henry.beberman@microsoft.com
This patch enables i.MX platforms to easily add a boot script to their U-Boot Proper environment to automatically load and execute an EFI firmware from the first FAT partition of an MMC device.
Is there a reason to force the first partition instead of using the EFI partition code to select which partition to boot?
I also wonder, on a Linux system, is there a reason the EFI partition must use FAT?
I need to revise the commit message for this patch. The script is not fixed
to the first partition of the selected MMC, it scans the disk for partitions marked bootable, then checks each one of those until it finds the imxboard_efi.fd binary.
That is indeed very different from first FAT partition. Does bootable only apply legacy MBR partition tables? I didn't think bootable was typically used with GPT tables. There is a bit, but it's not used to mark EFI partitions.
Which brings me back to the partition type. Isn't that the right way to find the EFI?
The is_bootable function in disk/part_efi.c marks a partition as bootable if the partition_type_guid on disk matches the EFI PARTITION_SYSTEM_GUID. The part command with the -bootable flag will return the EFI partition on both GPT and MBR partition schemes. This method is also used by config_distro_bootcmd.h
We could switch over to using the generic load from
CONFIG_CMD_FS_GENERIC if there's demand for non-FAT filesystems. We're currently using fatload because the EFI partitions in our Windows images are always FAT formatted.
You're original search method required the partition be FAT.
I'm happy to switch from the fatload command over to the load command if it will make CONFIG_UEFI_BOOT more widely useful.