Chris, Stephen,

Have you tried using these custom patches from TI? There was a recent LSP 1.20 
patch release from TI to address the SDHC, SDIO support and MMC/SD performance 
improvements. The release is patch level 14 against LSP 1.20.

Thanks
Sneha

________________________________
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Stephen Berry
Sent: Wednesday, August 27, 2008 7:21 PM
To: Chris Stillson
Cc: [email protected]
Subject: Re: SDHC on dm355

Hi Chris,

I've been using the "optional" drivers for SDHC and atheros wireless on our 
DM355 product. But there are issues with it. In order to get the drivers to 
behave with the TI codecs I've had to turn off DMA.

I believe this is related to the errata on the SDIO DMA slots issued by Ti:

2.1.4    SD/SDIO card: How to Read M bytes (M=1, 2, 3) from SD or SDIO card
      Direction: Read from SD or SDIO
      Data size: 32*N+M byte (where M=1, 2, 3 and N=0, 1, 2, 3,...) FIFO size 
is 32 bytes (ACCWD (FIFOCTL
      [4:3] = 0), FIFO trigger level is 256-bits (FIFOLEV (MMCFIFOCTL [2]) =1)
      Reading from SD or SDIO when FIFO Trigger Level FIFOLEV is 256 bits 
causes the
      DRRDY(MMCST0[10]) bit not to be set for the last M bytes of the above 
data size equation and therefore
      the DMA read event and CPU interrupt for RRDY(MMCST0[10]) are not getting 
asserted, but the data in
      FIFO is correct.
      There are two possible methods to work around this limitation.
      1. Include SD status checking and/or SD interrupt enable for TRNDNE 
(MMCST0 [12]) or DATDNE
          (MMCST0 [0])
      2. Use 128-bit FIFO trigger level (i.e. FIFOLEV (MMCFIFOCTL [2]) =0), 
since this is only a problem when
          FIFOLEV is 256 bits.
      Note:

In any case, the drivers should be available as loadable kernel modules with 
the latest distribution. They are also available on the cardaccess web site:
http://www.cardaccess-inc.com/support/wlan/index.php?a=wlan_burt -- along with 
directions on how to build them into your kernel.

The drivers will replace the original kernel drivers and you shouldn't have a 
problem using SDHC... as long as you turn off DMA. Use the no_dma=1 parameter:
    insmod sdio_davinci_hcd.ko no_dma=1

Good luck,

 Steve

Chris Stillson wrote:

Has anyone actually used sdhc card on a dm355? The docs say it isn't

supported, but I'm wondering if it can be worked around.



Chris



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