[U-Boot] [PATCH] spl_mmc: always use find_mmc_device() to get mmc handler

[jason.zhu at rock-chips.com]

Hi,

    We use the aliases to set the MMC device order. For example:
        mmc0 = &emmc;
        mmc1 = &sdmmc;
    These define the MMC order in block layer.
    But in the mmc layer, the MMC device order is defined in the dts MMC node.
    It may make mistake to get MMC device order. So if we use the block layer interface to
access mmc devices, use find_mmc_device to get current devnum but not uclass_get_device.

Thanks and regards,
Jason



jason.zhu at rock-chips.com
 
From: Lokesh Vutla
Date: 2019-07-25 18:39
To: Kever Yang; u-boot at lists.denx.de
CC: jason.zhu at rock-chips.com; Marek Vasut; Tien Fong Chee; Peng Fan
Subject: Re: [U-Boot] [PATCH] spl_mmc: always use find_mmc_device() to get mmc handler
+Peng
 
Hi Kever,
 
On 25/07/19 3:10 PM, Kever Yang wrote:
> Like cmd/mmc.c, the spl_mmc.c are using block driver interface
> like blk_dread() to access mmc devices, we need to get the mmc device
> handler by block driver interface so that we can always get correct
> device number, eg. the alias may change the device number which make
> the device number different in UCLASS_MMC list and UCLASS_BLK list.
> 
> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
> ---
> 
>  common/spl/spl_mmc.c | 9 ---------
>  1 file changed, 9 deletions(-)
> 
> diff --git a/common/spl/spl_mmc.c b/common/spl/spl_mmc.c
> index b3619889f7..3a93e20f04 100644
> --- a/common/spl/spl_mmc.c
> +++ b/common/spl/spl_mmc.c
> @@ -113,9 +113,6 @@ static int spl_mmc_get_device_index(u32 boot_device)
>  
>  static int spl_mmc_find_device(struct mmc **mmcp, u32 boot_device)
>  {
> -#if CONFIG_IS_ENABLED(DM_MMC)
> - struct udevice *dev;
> -#endif
>  int err, mmc_dev;
>  
>  mmc_dev = spl_mmc_get_device_index(boot_device);
> @@ -130,14 +127,8 @@ static int spl_mmc_find_device(struct mmc **mmcp, u32 boot_device)
>  return err;
>  }
>  
> -#if CONFIG_IS_ENABLED(DM_MMC)
> - err = uclass_get_device(UCLASS_MMC, mmc_dev, &dev);
> - if (!err)
> - *mmcp = mmc_get_mmc_dev(dev);
> -#else
>  *mmcp = find_mmc_device(mmc_dev);
>  err = *mmcp ? 0 : -ENODEV;
> -#endif
 
I am not against the change but trying to understand what is the problem you
faced. mmc_initialize() would have initialized the devices based on the seq
number that is provided in DT. So in your case shouldn't uclass_get_device give
the right device or something else triggered this patch?
 
Also we are facing a different problem with mmc_initialize(). Very early in boot
there is no access to any peripheral other than boot peripheral(Need system co
processor to enable peripherals). There are 2 MMC controllers in our devices.
So, SD boot is failing while loading system firmware as mmc_initialize is trying
to probe both the controllers. In SPL, shouldn't we just probe the needed
controller instead of calling mmc_initialize?
 
Thanks and regards,
Lokesh