On Tue, Jun 12, 2012 at 10:40 AM, Girish K S <girish.shivananjappa@xxxxxxxxxx> wrote: > On 12 June 2012 15:05, Will Newton <will.newton@xxxxxxxxx> wrote: >> On Tue, Jun 12, 2012 at 10:01 AM, Girish K S >> <girish.shivananjappa@xxxxxxxxxx> wrote: >>> On 12 June 2012 14:25, Will Newton <will.newton@xxxxxxxxx> wrote: >>>> On Tue, Jun 12, 2012 at 5:21 AM, Girish K S >>>> <girish.shivananjappa@xxxxxxxxxx> wrote: >>>>> >>>>> In the Current dwmmc driver there is support for selecting IDMAC from >>>>> the menu config option. If the support for IDMAC is enabled in the menu >>>>> config and Hardware configuration register's DMA_INTERFACE field is 0. >>>>> Still the driver will try to do the DMA initialization. >>>>> >>>>> The dw_mci_idmac_init function currently implemented returns only success >>>>> indicating that the DMA initialization is always successful. The current >>>>> patch will add a ciheck for existance of the DMA IP and allow the >>>>> DMA initialization. >>>>> >>>>> Signed-off-by: Girish K S <girish.shivananjappa@xxxxxxxxxx> >>>>> --- >>>>> drivers/mmc/host/dw_mmc.c | 11 ++++++++++- >>>>> 1 files changed, 10 insertions(+), 1 deletions(-) >>>> >>>> This looks ok in principle. I'm wondering if we should only allow >>>> dma_support == 0x01 (DW_DMA) in the IDMAC case? It's not clear from >>>> the TRM what each of the DMA values means and I only have a system >>>> with external DMA support at the moment. >>> My understanding from the TRM >>> if dma_support =1; then use designware dma ip for internal >>> dma_support =2 then use any generic dma ip for internal dma tx >>> this config is only for IDMA support. If there is a external DMA CTRL >>> register should be used explicitly to enable DMA (there is no config >>> available to tell external dma supported). correct me if i am wrong. >> >> That sounds like a reasonable interpretation of the TRM. ;-) >> >> Acked-by: Will Newton <will.newton@xxxxxxxxxx> > I will resend the patch with minor change so that kernel doesnt crash > but use PIO mode and continue even if IDMAC is enabled accidentally. > what s your say? Yes, let's make sure it is robust against errors in configuration. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
