Re: [PATCH v5] spi: spi-imx: add DMA support

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Kernel]     [Linux ARM (vger)]     [Linux ARM MSM]     [Linux Omap]     [Linux Arm]     [Linux Tegra]     [Fedora ARM]     [Linux for Samsung SOC]     [eCos]     [Linux Fastboot]     [Gcc Help]     [Git]     [DCCP]     [IETF Announce]     [Security]     [Linux MIPS]     [Yosemite Campsites]

  Powered by Linux