| Message ID | 20170105061015.7816-1-jiada_wang@mentor.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@mentor.com> > --- > 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@pengutronix.de> * Shawn Guo <shawn.guo@linaro.org> * Alexander Shiyan <shc_work@mail.ru> -- With best wishes, Vladimir -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jan 05, 2017 at 03:10:15PM +0900, 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. Doesn't this just move the problem around a bit - can we not have the driver figure out a more sensible watermark for each transfer rather than fixing one in the DT?
Hello Mark and Vladimir On 01/05/2017 09:58 AM, Mark Brown wrote: > On Thu, Jan 05, 2017 at 03:10:15PM +0900, 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. > Doesn't this just move the problem around a bit - can we not have the > driver figure out a more sensible watermark for each transfer rather > than fixing one in the DT? I would like to submit another version of patch to adjust watermark level based on transfer length. to use largest number (< fifosize / 2 ) which can divide (transfer_length / bytes_per_work). Thanks, Jiada -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 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>; }; 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; + } else + spi_imx->wml = spi_imx_get_fifosize(spi_imx) / 2; + if (mxc_platform_info) { master->num_chipselect = mxc_platform_info->num_chipselect; master->cs_gpios = devm_kzalloc(&master->dev,
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@mentor.com> --- Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt | 2 ++ drivers/spi/spi-imx.c | 12 ++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-)