Re: [PATCH v2 4/7] mmc: uniphier-sd: add UniPhier SD/eMMC controller driver

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thu, Aug 16, 2018 at 04:16:36PM +0900, Masahiro Yamada wrote:
> Here is another TMIO MMC variant found in Socionext UniPhier SoCs.
> 
> As commit b6147490e6aa ("mmc: tmio: split core functionality, DMA and
> MFD glue") said, these MMC controllers use the IP from Panasonic.
> 
> However, the MMC controller in the TMIO (Toshiba Mobile IO) MFD chip
> was the first upstreamed user of this IP.  The common driver code
> for this IP is now called 'tmio-mmc-core' in Linux although it is a
> historical misnomer.
> 
> Anyway, this driver select's MMC_TMIO_CORE to borrow the common code
> from tmio-mmc-core.c
> 
> Older UniPhier SoCs (LD4, Pro4, sLD8) support the external DMA engine
> like renesas_sdhi_sys_dmac.c.  The difference is UniPhier SoCs use a
> single DMA channel whereas Renesas chips request separate channels for
> RX and TX.
> 
> Newer UniPhier SoCs (Pro5 and later) support the internal DMA engine
> like renesas_sdhi_internal_dmac.c  The register map is almost the same,
> so I guess Renesas and Socionext use the same internal DMA hardware.
> The main difference is, the register offsets are doubled for Renesas.
> 
>                         Renesas      Socionext
>                         SDHI         UniPhier
>   DM_CM_DTRAN_MODE      0x820        0x410
>   DM_CM_DTRAN_CTRL      0x828        0x414
>   DM_CM_RST             0x830        0x418
>   DM_CM_INFO1           0x840        0x420
>   DM_CM_INFO1_MASK      0x848        0x424
>   DM_CM_INFO2           0x850        0x428
>   DM_CM_INFO2_MASK      0x858        0x42c
>   DM_DTRAN_ADDR         0x880        0x440
>   DM_DTRAN_ADDREX        ---         0x444
> 
> This comes from the difference of host->bus_shift; 2 for Renesas SoCs,
> and 1 for UniPhier SoCs.  Also, the datasheet for UniPhier SoCs defines
> DM_DTRAN_ADDR and DM_DTRAN_ADDREX as two separate registers.
> 
> It could be possible to factor out the DMA common code by introducing
> some hooks to cope with platform quirks, but this patch does not touch
> that for now.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>

Without docs and HW I cannot really review the driver, but it looks good
and it makes sense to me to keep it seperate and not factor out more
SDHI stuff. Thus:

Acked-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>

Attachment: signature.asc
Description: PGP signature


[Index of Archives]     [Linux Memonry Technology]     [Linux USB Devel]     [Linux Media]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux