Hi Jiada,
On 01/05/2017 08:10 AM, Jiada Wang wrote:
> Previously watermark level is configured to fifosize/2,
> DMA mode can be used only when transfer length can be divided
> by 'watermark level * bpw', which makes DMA mode not practical.
>
> This patch adds new DTS property 'dma-wml', user can configure
> DMA watermark level, by specify 'dma-wml' in corresponding ecspi
> node.
>
> Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt | 2 ++
> drivers/spi/spi-imx.c | 12 ++++++++++--
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt b/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt
> index 8bc95e2..1e9345f 100644
> --- a/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt
> +++ b/Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt
> @@ -19,6 +19,7 @@ See the clock consumer binding,
> - dmas: DMA specifiers for tx and rx dma. See the DMA client binding,
> Documentation/devicetree/bindings/dma/dma.txt
> - dma-names: DMA request names should include "tx" and "rx" if present.
> +- dma-wml: Specifies DMA watermark level
It is supposed to be an optional property, please add a new section.
I'm not sure about the property naming, the property may be considered
as a generic one and then it should not have 'fsl' prefix like yours one,
but then its description should be moved to bindings/spi/spi-bus.txt.
On the other hand for a kind of generic property it might be desirable
to have two properties, DMA RX and DMA TX watermark (threshold) levels.
And the property may be defined as a combined DMA RX / DMA TX watermark
specific to the Freescale ECSPI controller (however I would propose to
separate them, since the hardware allows to do it), but then please add
'fsl' prefix.
>
> Obsolete properties:
> - fsl,spi-num-chipselects : Contains the number of the chipselect
> @@ -35,4 +36,5 @@ ecspi@70010000 {
> <&gpio3 25 0>; /* GPIO3_25 */
> dmas = <&sdma 3 7 1>, <&sdma 4 7 2>;
> dma-names = "rx", "tx";
> + dma-wml = <16>;
Please use tab symbols for indentation.
> };
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index deb782f..5c0ce19 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -929,8 +929,6 @@ static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
> if (of_machine_is_compatible("fsl,imx6dl"))
> return 0;
>
> - spi_imx->wml = spi_imx_get_fifosize(spi_imx) / 2;
> -
> /* Prepare for TX DMA: */
> master->dma_tx = dma_request_slave_channel_reason(dev, "tx");
> if (IS_ERR(master->dma_tx)) {
> @@ -1155,6 +1153,7 @@ static int spi_imx_probe(struct platform_device *pdev)
> struct spi_imx_data *spi_imx;
> struct resource *res;
> int i, ret, irq;
> + u32 wml;
>
> if (!np && !mxc_platform_info) {
> dev_err(&pdev->dev, "can't get the platform data\n");
> @@ -1177,6 +1176,15 @@ static int spi_imx_probe(struct platform_device *pdev)
> spi_imx->devtype_data = of_id ? of_id->data :
> (struct spi_imx_devtype_data *)pdev->id_entry->driver_data;
>
> + if (of_property_read_u32(np, "dma-wml", &wml) == 0) {
> + if (wml > spi_imx_get_fifosize(spi_imx) || wml == 0) {
> + dev_warn(&pdev->dev, "mis-configured dma-wml\n");
> + spi_imx->wml = spi_imx_get_fifosize(spi_imx) / 2;
> + } else
> + spi_imx->wml = wml;
checkpatch should complain regarding missing bracers on the "else" branch.
> + } else
> + spi_imx->wml = spi_imx_get_fifosize(spi_imx) / 2;
> +
Same is here.
Since the setting depends on the availability of DMA feature, it would be
better to read the property out from spi_imx_sdma_init():
spi_imx->wml = spi_imx_get_fifosize(spi_imx) / 2;
if (!of_property_read_u32(np, "dma-wml", &wml)) {
if (!wml || wml > spi_imx_get_fifosize(spi_imx)) /* power of 2 also? */
dev_warn(&pdev->dev, "mis-configured dma-wml\n");
else
spi_imx->wml = wml;
}
> if (mxc_platform_info) {
> master->num_chipselect = mxc_platform_info->num_chipselect;
> master->cs_gpios = devm_kzalloc(&master->dev,
>
For v2 please add to cc list:
* Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
* Shawn Guo <shawn.guo@xxxxxxxxxx>
* Alexander Shiyan <shc_work@xxxxxxx>
--
With best wishes,
Vladimir
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