Hi Mikko, On Mon, Mar 07 2011, Mikko Vinni wrote: > Some SD host controllers (noticed on an integrated JMicron SD reader > on an HP Pavilion dv5-1250eo laptop) don't update the dma address > register before signaling a dma interrupt due to a dma boundary. > Detect this and update the register to the next 512KB boundary, > at which the transfer presumably stopped. > > As long as each transfer is at most 512KB in size (on this hardware > the max seems to be 65536 bytes), this fix is needed at most once > per transfer. > > Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=28462 > > Signed-off-by: Mikko Vinni <mmvinni <at> yahoo.com> > --- > Sent on 2011-02-21 21:23:32 GMT > (http://thread.gmane.org/gmane.linux.kernel.mmc/5568/focus=6145) > > Hoping to be able to drop this patch eventually from my own > repo and have the hardware just work with mainline code. > Maybe first in -next if nobody sees any serious problems > straight away? > > This patch should not break anything for anybody whose > hardware isn't already broken. > > drivers/mmc/host/sdhci.c | 24 +++++++++++++++++++++--- > 1 files changed, 21 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index a25db42..8651731 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -1537,9 +1537,27 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask) > * boundaries, but as we can't disable the feature > * we need to at least restart the transfer. > */ > - if (intmask & SDHCI_INT_DMA_END) > - sdhci_writel(host, sdhci_readl(host, SDHCI_DMA_ADDRESS), > - SDHCI_DMA_ADDRESS); > + if (intmask & SDHCI_INT_DMA_END) { > + u32 dmastart, dmanow; > + dmastart = sg_dma_address(host->data->sg); > + dmanow = sdhci_readl(host, SDHCI_DMA_ADDRESS); > + if (dmanow == dmastart) { > + /* > + * HW failed to increase the address. > + * Update to the next 512KB block boundary. > + */ > + dmanow = (dmanow & ~0x7ffff) + 0x80000; > + if (dmanow > dmastart + host->data->blksz * > + host->data->blocks) { > + WARN_ON(1); > + dmanow = dmastart; > + } > + DBG("%s: next DMA address forced " > + "from 0x%08x to 0x%08x\n", > + mmc_hostname(host->mmc), dmastart, dmanow); > + } > + sdhci_writel(host, dmanow, SDHCI_DMA_ADDRESS); > + } > > if (intmask & SDHCI_INT_DATA_END) { > if (host->cmd) { Thanks, I agree, pushed to -next for testing. I'd still appreciate a Reviewed-by: from someone on linux-mmc@, and would like to hear if anyone thinks this needs to be a quirk rather than a generic fix. - Chris. -- Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/> One Laptop Per Child -- 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
