From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Gong Subject: Re: [PATCH v5] spi: spi-imx: add DMA support Date: Wed, 10 Sep 2014 19:22:59 +0800 Message-ID: <20140910112258.GA30794@Robin-OptiPlex-780> References: <1410312604-31949-1-git-send-email-b38343@freescale.com> <20140910102105.GR2601@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: , , , , , To: Mark Brown Return-path: Content-Disposition: inline In-Reply-To: <20140910102105.GR2601-GFdadSzt00ze9xe1eoZjHA@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: On Wed, Sep 10, 2014 at 11:21:05AM +0100, Mark Brown wrote: > On Wed, Sep 10, 2014 at 09:30:04AM +0800, Robin Gong wrote: > > > +static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi, > > + struct spi_transfer *transfer) > > +{ > > + struct spi_imx_data *spi_imx = spi_master_get_devdata(master); > > + > > + if (spi_imx->dma_is_inited && (transfer->len > spi_imx->rx_wml) > > + && (transfer->len > spi_imx->tx_wml)) > > + spi_imx->usedma = true; > > + else > > + spi_imx->usedma = false; > > + > > + return spi_imx->usedma; > > +} > > This isn't going to work, anything that looks at the usedma flag will > see the result of the last thing that was checked which may or may not > be the transfer that it's handling. The driver should check to see if > the core mapped the transfer for DMA. Yes, you're right. I should use "transfer->tx_sg->sgl == NULL" or "transfer->rx_sg->sgl == NULL" instead of usedma flag in driver, right? -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html