> -----Original Message----- > From: [email protected] [mailto:linux-mmc- > [email protected]] On Behalf Of Venkatraman S > Sent: Monday, March 01, 2010 5:26 AM > To: [email protected]; [email protected]; > [email protected] > Subject: [PATCH 01/03] omap hsmmc: prevent race between dma and hsmmc > callback > > It is observed that sometimes the MMC Transfer Complete (TC) is not > received when DMA completion callback is processed (or takes too long > to process) > This patch moves the releasing of DMA channel from dma callback to the > mmc transfer complete handler. > This is observed consistently when descriptor loading is used (see the > rest of the series) > > Signed-off-by: Venkatraman S <[email protected]> > --- > drivers/mmc/host/omap_hsmmc.c | 19 +++++++++++-------- > 1 files changed, 11 insertions(+), 8 deletions(-) > > diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c > index 83f0aff..06337f6 100644 > --- a/drivers/mmc/host/omap_hsmmc.c > +++ b/drivers/mmc/host/omap_hsmmc.c > @@ -1046,8 +1046,18 @@ static irqreturn_t omap_hsmmc_irq(int irq, void > *dev_id) > > if (end_cmd || ((status & CC) && host->cmd)) > omap_hsmmc_cmd_done(host, host->cmd); > - if ((end_trans || (status & TC)) && host->mrq) > + if ((end_trans || (status & TC)) && host->mrq) { > omap_hsmmc_xfer_done(host, data); > + if (host->dma_ch != -1) { > + omap_free_dma(host->dma_ch); > + host->dma_ch = -1;
Why is this necessary? The core is notified of xfer complete only when TC is received which is good enough. > + /* > + * Callback: run in interrupt context. > + * mutex_unlock will throw a kernel warning if used. > + */ > + up(&host->sem); > + } > + } > > spin_unlock(&host->irq_lock); > > @@ -1267,13 +1277,6 @@ static void omap_hsmmc_dma_cb(int lch, u16 > ch_status, void *data) > return; > } > > - omap_free_dma(host->dma_ch); > - host->dma_ch = -1; > - /* > - * DMA Callback: run in interrupt context. > - * mutex_unlock will throw a kernel warning if used. > - */ > - up(&host->sem); > } > > /* > -- > 1.6.3.3 > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
