[PATCH v3] DMA: shdma: add DT support

Vinod Koul vinod.koul at intel.com
Tue Jun 25 20:51:23 EST 2013


On Tue, Jun 18, 2013 at 06:16:57PM +0200, Guennadi Liakhovetski wrote:
> This patch adds Device Tree support to the shdma driver. No special DT
> properties are used, only standard DMA DT bindings are implemented. Since
> shdma controllers reside on SoCs, their configuration is SoC-specific and
> shall be passed to the driver from the SoC platform data, using the
> auxdata procedure.
> 
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas at gmail.com>
Applied thanks.

Though checkpatch cribbed about space and tabs, fixed up manually...

--
~Vinod
> ---
> 
> v3: reimplementation without a common DMAC multiplexer support in 
> dmaengine core, the multiplexer is now SHDMA local.
> 
>  Documentation/devicetree/bindings/dma/shdma.txt |   75 +++++++++++++++++++++
>  drivers/dma/sh/Makefile                         |    2 +-
>  drivers/dma/sh/shdma-base.c                     |   26 ++++++--
>  drivers/dma/sh/shdma-of.c                       |   82 +++++++++++++++++++++++
>  drivers/dma/sh/shdma.c                          |   31 +++++++--
>  include/linux/shdma-base.h                      |    2 +
>  6 files changed, 205 insertions(+), 13 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/dma/shdma.txt
>  create mode 100644 drivers/dma/sh/shdma-of.c
> 
> diff --git a/Documentation/devicetree/bindings/dma/shdma.txt b/Documentation/devicetree/bindings/dma/shdma.txt
> new file mode 100644
> index 0000000..c15994a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/shdma.txt
> @@ -0,0 +1,75 @@
> +* SHDMA Device Tree bindings
> +
> +Sh-/r-mobile and r-car systems often have multiple identical DMA controller
> +instances, capable of serving any of a common set of DMA slave devices, using
> +the same configuration. To describe this topology we require all compatible
> +SHDMA DT nodes to be placed under a DMA multiplexer node. All such compatible
> +DMAC instances have the same number of channels and use the same DMA
> +descriptors. Therefore respective DMA DT bindings can also all be placed in the
> +multiplexer node. Even if there is only one such DMAC instance on a system, it
> +still has to be placed under such a multiplexer node.
> +
> +* DMA multiplexer
> +
> +Required properties:
> +- compatible:	should be "renesas,shdma-mux"
> +- #dma-cells:	should be <1>, see "dmas" property below
> +
> +Optional properties (currently unused):
> +- dma-channels:	number of DMA channels
> +- dma-requests:	number of DMA request signals
> +
> +* DMA controller
> +
> +Required properties:
> +- compatible:	should be "renesas,shdma"
> +
> +Example:
> +	dmac: dma-mux0 {
> +		compatible = "renesas,shdma-mux";
> +		#dma-cells = <1>;
> +		dma-channels = <6>;
> +		dma-requests = <256>;
> +		reg = <0 0>;	/* Needed for AUXDATA */
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		ranges;
> +
> +		dma0: shdma at fe008020 {
> +			compatible = "renesas,shdma";
> +			reg = <0xfe008020 0x270>,
> +				<0xfe009000 0xc>;
> +			interrupt-parent = <&gic>;
> +			interrupts = <0 34 4
> +					0 28 4
> +					0 29 4
> +					0 30 4
> +					0 31 4
> +					0 32 4
> +					0 33 4>;
> +			interrupt-names = "error",
> +					"ch0", "ch1", "ch2", "ch3",
> +					"ch4", "ch5";
> +		};
> +
> +		dma1: shdma at fe018020 {
> +			...
> +		};
> +
> +		dma2: shdma at fe028020 {
> +			...
> +		};
> +	};
> +
> +* DMA client
> +
> +Required properties:
> +- dmas:		a list of <[DMA multiplexer phandle] [MID/RID value]> pairs,
> +		where MID/RID values are fixed handles, specified in the SoC
> +		manual
> +- dma-names:	a list of DMA channel names, one per "dmas" entry
> +
> +Example:
> +	dmas = <&dmac 0xd1
> +		&dmac 0xd2>;
> +	dma-names = "tx", "rx";
> diff --git a/drivers/dma/sh/Makefile b/drivers/dma/sh/Makefile
> index c07ca46..c962138 100644
> --- a/drivers/dma/sh/Makefile
> +++ b/drivers/dma/sh/Makefile
> @@ -1,3 +1,3 @@
> -obj-$(CONFIG_SH_DMAE_BASE) += shdma-base.o
> +obj-$(CONFIG_SH_DMAE_BASE) += shdma-base.o shdma-of.o
>  obj-$(CONFIG_SH_DMAE) += shdma.o
>  obj-$(CONFIG_SUDMAC) += sudmac.o
> diff --git a/drivers/dma/sh/shdma-base.c b/drivers/dma/sh/shdma-base.c
> index 4acb85a..28ca361 100644
> --- a/drivers/dma/sh/shdma-base.c
> +++ b/drivers/dma/sh/shdma-base.c
> @@ -175,7 +175,18 @@ static int shdma_setup_slave(struct shdma_chan *schan, int slave_id)
>  {
>  	struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
>  	const struct shdma_ops *ops = sdev->ops;
> -	int ret;
> +	int ret, match;
> +
> +	if (schan->dev->of_node) {
> +		match = schan->hw_req;
> +		ret = ops->set_slave(schan, match, true);
> +		if (ret < 0)
> +			return ret;
> +
> +		slave_id = schan->slave_id;
> +	} else {
> +		match = slave_id;
> +	}
>  
>  	if (slave_id < 0 || slave_id >= slave_num)
>  		return -EINVAL;
> @@ -183,7 +194,7 @@ static int shdma_setup_slave(struct shdma_chan *schan, int slave_id)
>  	if (test_and_set_bit(slave_id, shdma_slave_used))
>  		return -EBUSY;
>  
> -	ret = ops->set_slave(schan, slave_id, false);
> +	ret = ops->set_slave(schan, match, false);
>  	if (ret < 0) {
>  		clear_bit(slave_id, shdma_slave_used);
>  		return ret;
> @@ -206,23 +217,26 @@ static int shdma_setup_slave(struct shdma_chan *schan, int slave_id)
>   * services would have to provide their own filters, which first would check
>   * the device driver, similar to how other DMAC drivers, e.g., sa11x0-dma.c, do
>   * this, and only then, in case of a match, call this common filter.
> + * NOTE 2: This filter function is also used in the DT case by shdma_of_xlate().
> + * In that case the MID-RID value is used for slave channel filtering and is
> + * passed to this function in the "arg" parameter.
>   */
>  bool shdma_chan_filter(struct dma_chan *chan, void *arg)
>  {
>  	struct shdma_chan *schan = to_shdma_chan(chan);
>  	struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
>  	const struct shdma_ops *ops = sdev->ops;
> -	int slave_id = (int)arg;
> +	int match = (int)arg;
>  	int ret;
>  
> -	if (slave_id < 0)
> +	if (match < 0)
>  		/* No slave requested - arbitrary channel */
>  		return true;
>  
> -	if (slave_id >= slave_num)
> +	if (!schan->dev->of_node && match >= slave_num)
>  		return false;
>  
> -	ret = ops->set_slave(schan, slave_id, true);
> +	ret = ops->set_slave(schan, match, true);
>  	if (ret < 0)
>  		return false;
>  
> diff --git a/drivers/dma/sh/shdma-of.c b/drivers/dma/sh/shdma-of.c
> new file mode 100644
> index 0000000..9ab869d
> --- /dev/null
> +++ b/drivers/dma/sh/shdma-of.c
> @@ -0,0 +1,82 @@
> +/*
> + * SHDMA Device Tree glue
> + *
> + * Copyright (C) 2013 Renesas Electronics Inc.
> + * Author: Guennadi Liakhovetski <g.liakhovetski at gmx.de>
> + *
> + * This is free software; you can redistribute it and/or modify
> + * it under the terms of version 2 of the GNU General Public License as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/dmaengine.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_dma.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/shdma-base.h>
> +
> +#define to_shdma_chan(c) container_of(c, struct shdma_chan, dma_chan)
> +
> +static struct dma_chan *shdma_of_xlate(struct of_phandle_args *dma_spec,
> +				       struct of_dma *ofdma)
> +{
> +	u32 id = dma_spec->args[0];
> +	dma_cap_mask_t mask;
> +	struct dma_chan *chan;
> +
> +	if (dma_spec->args_count != 1)
> +		return NULL;
> +
> +	dma_cap_zero(mask);
> +	/* Only slave DMA channels can be allocated via DT */
> +	dma_cap_set(DMA_SLAVE, mask);
> +
> +	chan = dma_request_channel(mask, shdma_chan_filter, (void *)id);
> +	if (chan)
> +		to_shdma_chan(chan)->hw_req = id;
> +
> +	return chan;
> +}
> +
> +static int shdma_of_probe(struct platform_device *pdev)
> +{
> +	const struct of_dev_auxdata *lookup = pdev->dev.platform_data;
> +	int ret;
> +
> +	if (!lookup)
> +		return -EINVAL;
> +
> +	ret = of_dma_controller_register(pdev->dev.of_node,
> +					 shdma_of_xlate, pdev);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = of_platform_populate(pdev->dev.of_node, NULL, lookup, &pdev->dev);
> +	if (ret < 0)
> +		of_dma_controller_free(pdev->dev.of_node);
> +
> +	return ret;
> +}
> +
> +static const struct of_device_id shdma_of_match[] = {
> +	{ .compatible = "renesas,shdma-mux", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, sh_dmae_of_match);
> +
> +static struct platform_driver shdma_of = {
> +	.driver 	= {
> +		.owner	= THIS_MODULE,
> +		.name	= "shdma-of",
> +		.of_match_table = shdma_of_match,
> +	},
> +	.probe		= shdma_of_probe,
> +};
> +
> +module_platform_driver(shdma_of);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("SH-DMA driver DT glue");
> +MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski at gmx.de>");
> diff --git a/drivers/dma/sh/shdma.c b/drivers/dma/sh/shdma.c
> index a5a1887..b67f45f 100644
> --- a/drivers/dma/sh/shdma.c
> +++ b/drivers/dma/sh/shdma.c
> @@ -301,20 +301,32 @@ static void sh_dmae_setup_xfer(struct shdma_chan *schan,
>  	}
>  }
>  
> +/*
> + * Find a slave channel configuration from the contoller list by either a slave
> + * ID in the non-DT case, or by a MID/RID value in the DT case
> + */
>  static const struct sh_dmae_slave_config *dmae_find_slave(
> -	struct sh_dmae_chan *sh_chan, int slave_id)
> +	struct sh_dmae_chan *sh_chan, int match)
>  {
>  	struct sh_dmae_device *shdev = to_sh_dev(sh_chan);
>  	struct sh_dmae_pdata *pdata = shdev->pdata;
>  	const struct sh_dmae_slave_config *cfg;
>  	int i;
>  
> -	if (slave_id >= SH_DMA_SLAVE_NUMBER)
> -		return NULL;
> +	if (!sh_chan->shdma_chan.dev->of_node) {
> +		if (match >= SH_DMA_SLAVE_NUMBER)
> +			return NULL;
>  
> -	for (i = 0, cfg = pdata->slave; i < pdata->slave_num; i++, cfg++)
> -		if (cfg->slave_id == slave_id)
> -			return cfg;
> +		for (i = 0, cfg = pdata->slave; i < pdata->slave_num; i++, cfg++)
> +			if (cfg->slave_id == match)
> +				return cfg;
> +	} else {
> +		for (i = 0, cfg = pdata->slave; i < pdata->slave_num; i++, cfg++)
> +			if (cfg->mid_rid == match) {
> +				sh_chan->shdma_chan.slave_id = cfg->slave_id;
> +				return cfg;
> +			}
> +	}
>  
>  	return NULL;
>  }
> @@ -920,11 +932,18 @@ static int sh_dmae_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static const struct of_device_id sh_dmae_of_match[] = {
> +	{ .compatible = "renesas,shdma", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, sh_dmae_of_match);
> +
>  static struct platform_driver sh_dmae_driver = {
>  	.driver 	= {
>  		.owner	= THIS_MODULE,
>  		.pm	= &sh_dmae_pm,
>  		.name	= SH_DMAE_DRV_NAME,
> +		.of_match_table = sh_dmae_of_match,
>  	},
>  	.remove		= sh_dmae_remove,
>  	.shutdown	= sh_dmae_shutdown,
> diff --git a/include/linux/shdma-base.h b/include/linux/shdma-base.h
> index 9a93897..382cf71 100644
> --- a/include/linux/shdma-base.h
> +++ b/include/linux/shdma-base.h
> @@ -68,6 +68,8 @@ struct shdma_chan {
>  	int id;				/* Raw id of this channel */
>  	int irq;			/* Channel IRQ */
>  	int slave_id;			/* Client ID for slave DMA */
> +	int hw_req;			/* DMA request line for slave DMA - same
> +					 * as MID/RID, used with DT */
>  	enum shdma_pm_state pm_state;
>  };
>  
> -- 
> 1.7.2.5
> 

-- 


More information about the devicetree-discuss mailing list