[RFC PATCH 2/3] sunxi: Implement fastboot_get_mmc_device()

[Sean Anderson]

On 5/23/21 8:36 PM, Andre Przywara wrote:
> The default MMC device to use for the fastboot flash command is hard to
> decide at runtime, since the numbering of the MMC devices depends on
> devicetree nodes. On the hardware side, the eMMC is connected to device
> 2, but this might be U-Boot's device 1 or 2, depending on whether the DT
> contains a WiFi node for the hardware MMC1 device.

Can you fix this with aliases? e.g.

aliases {
	mmc0 = &mmc0;
	mmc1 = &mmc1;
	mmc2 = &mmc2;
};

That way the mmcs will always have the same number even if (e.g.) hardware mmc 1 is absent.

--Sean

> 
> To avoid hardcoding this for each board, let's scan all MMC devices, and
> try to find the eMMC device, given that this is enabled. If not, we use
> the SD card.
> 
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
>   board/sunxi/board.c | 37 +++++++++++++++++++++++++++++++++++++
>   1 file changed, 37 insertions(+)
> 
> diff --git a/board/sunxi/board.c b/board/sunxi/board.c
> index 21651a1bfca..5f64887e48b 100644
> --- a/board/sunxi/board.c
> +++ b/board/sunxi/board.c
> @@ -625,6 +625,43 @@ int board_mmc_init(struct bd_info *bis)
>   }
>   #endif
>   
> +#ifdef CONFIG_FASTBOOT_FLASH_MMC
> +int fastboot_get_mmc_device(void)
> +{
> +	struct udevice *dev;
> +	static int mmc_dev = -1;
> +	int sd_card = -1;
> +
> +	if (mmc_dev != -1)
> +		return mmc_dev;
> +
> +	for (uclass_first_device(UCLASS_MMC, &dev);
> +	     dev;
> +	     uclass_next_device(&dev)) {
> +		struct mmc *mmc = mmc_get_mmc_dev(dev);
> +
> +		mmc_init(mmc);
> +		if (!mmc->has_init)
> +			continue;
> +
> +		if (IS_SD(mmc)) {
> +			sd_card = dev->seq_;
> +			continue;
> +		} else {
> +			mmc_dev =  dev->seq_;
> +			break;
> +		}
> +	}
> +
> +	if (mmc_dev == -1)
> +		mmc_dev = sd_card;
> +	if (mmc_dev == -1)
> +		mmc_dev = 0;
> +
> +	return mmc_dev;
> +}
> +#endif
> +
>   #ifdef CONFIG_SPL_BUILD
>   
>   static void sunxi_spl_store_dram_size(phys_addr_t dram_size)
>