[U-Boot] [PATCH 2/2] panda: Initialize MMC power from TWL6030 in SPL

[Paul Kocialkowski]

Le mercredi 24 août 2016 à 11:24 -0400, Tom Rini a écrit :
> On Wed, Aug 24, 2016 at 04:40:42PM +0200, Paul Kocialkowski wrote:
> > This adds support for initializing MMC power from TWL6030 in SPL, which
> > is required when the bootrom didn't power the MMC device yet and U-Boot
> > is to be loaded from MMC (e.g. after setting boot mode from the SYS_BOOT
> > pins in peripheral boot).
> 
> So you're loading SPL via USB?  If it's via serial I'd much rather just
> use the SPL Y-Modem support instead.  Also:

Right, I'm loading SPL via USB and wish to load u-boot.img via MMC, according to
the SYS_BOOT configuration.

This is useful when e.g. only UART Tx is exported from the device.

> [snip]
> > 
> > +/* MMCSD FS mode is preferred */
> > +#undef CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR
> 
> That's very much not true.  Distro boot is usually done with raw mode
> not FAT.

Fair enough. The problem here is that the omap-common bootcode will assume raw
mode when reading mmc boot media from SYS_BOOT pins. Raw mode is supposed to
fallback to FS mode (which is what I want), but
when CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR is defined, it'll go ahead and try
to load the image. Even if it reads garbage (no valid header), it'll still go
ahead and assume u-boot.bin. In practice, it means that raw mode can never fail
as long as CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR is set.

Setting CONFIG_SPL_ABORT_ON_RAW_IMAGE allows properly returning when no valid
header is found, but it conflicts with CONFIG_SPL_OS_BOOT.

If setting CONFIG_SPL_ABORT_ON_RAW_IMAGE seems agreeable to you (I don't think
anyone cares about u-boot.bin anymore), I could rework the logic there so that
there is no longer a conflict with CONFIG_SPL_OS_BOOT.

What do you think?

-- 
Paul Kocialkowski, developer of low-level free software for embedded devices

Website: https://www.paulk.fr/
Coding blog: https://code.paulk.fr/
Git repositories: https://git.paulk.fr/ https://git.code.paulk.fr/
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