* Matt Porter <mporter@xxxxxx> [130110 21:47]: > The EDMA DMAC has a hardware limitation that prevents supporting > scatter gather lists with any number of segments. The DMA Engine > API reports the maximum number of segments a channel can support > via the optional dma_get_channel_caps() API. If the nr_segs > capability is present, the value is used to configure mmc->max_segs > appropriately. Acked-by: Tony Lindgren <tony@xxxxxxxxxxx> > Signed-off-by: Matt Porter <mporter@xxxxxx> > --- > drivers/mmc/host/omap_hsmmc.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c > index e79b12d..f74bd69 100644 > --- a/drivers/mmc/host/omap_hsmmc.c > +++ b/drivers/mmc/host/omap_hsmmc.c > @@ -1769,6 +1769,7 @@ static int omap_hsmmc_probe(struct platform_device *pdev) > const struct of_device_id *match; > dma_cap_mask_t mask; > unsigned tx_req, rx_req; > + struct dmaengine_chan_caps *dma_chan_caps; > struct pinctrl *pinctrl; > > match = of_match_device(of_match_ptr(omap_mmc_of_match), &pdev->dev); > @@ -1935,6 +1936,11 @@ static int omap_hsmmc_probe(struct platform_device *pdev) > goto err_irq; > } > > + /* Some DMA Engines only handle a limited number of SG segments */ > + dma_chan_caps = dma_get_channel_caps(host->rx_chan, DMA_DEV_TO_MEM); > + if (dma_chan_caps && dma_chan_caps->seg_nr) > + mmc->max_segs = dma_chan_caps->seg_nr; > + > /* Request IRQ for MMC operations */ > ret = request_irq(host->irq, omap_hsmmc_irq, 0, > mmc_hostname(mmc), host); > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
