Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit faadc6e3 authored by Linus Walleij's avatar Linus Walleij
Browse files

dma: coh901318: add devicetree support 



This adds support for probing the COH 901 318 DMA controller
and channels from the device tree.

Contains portions of a sketch patch from Arnd Bergmann.

Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: default avatarVinod Koul <vinod.koul@intel.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent ba078d1b

Documentation/devicetree/bindings/dma/ste-coh901318.txt

0 → 100644
+32 −0
Original line number Diff line number Diff line 
ST-Ericsson COH 901 318 DMA Controller



This is a DMA controller which has begun as a fork of the

ARM PL08x PrimeCell VHDL code.



Required properties:

- compatible: should be "stericsson,coh901318"

- reg: register locations and length

- interrupts: the single DMA IRQ

- #dma-cells: must be set to <1>, as the channels on the

  COH 901 318 are simple and identified by a single number

- dma-channels: the number of DMA channels handled



Example:



dmac: dma-controller@c00020000 {

	compatible = "stericsson,coh901318";

	reg = <0xc0020000 0x1000>;

	interrupt-parent = <&vica>;

	interrupts = <2>;

	#dma-cells = <1>;

	dma-channels = <40>;

};



Consumers example:



uart0: serial@c0013000 {

	compatible = "...";

	(...)

	dmas = <&dmac 17 &dmac 18>;

	dma-names = "tx", "rx";

};

drivers/dma/coh901318.c

+43 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include <linux/uaccess.h>

#include <linux/debugfs.h>

#include <linux/platform_data/dma-coh901318.h>

#include <linux/of_dma.h>



#include "coh901318.h"

#include "dmaengine.h"
@@ -1788,6 +1789,35 @@ bool coh901318_filter_id(struct dma_chan *chan, void *chan_id) 
}

EXPORT_SYMBOL(coh901318_filter_id);



struct coh901318_filter_args {

	struct coh901318_base *base;

	unsigned int ch_nr;

};



static bool coh901318_filter_base_and_id(struct dma_chan *chan, void *data)

{

	struct coh901318_filter_args *args = data;



	if (&args->base->dma_slave == chan->device &&

	    args->ch_nr == to_coh901318_chan(chan)->id)

		return true;



	return false;

}



static struct dma_chan *coh901318_xlate(struct of_phandle_args *dma_spec,

					struct of_dma *ofdma)

{

	struct coh901318_filter_args args = {

		.base = ofdma->of_dma_data,

		.ch_nr = dma_spec->args[0],

	};

	dma_cap_mask_t cap;

	dma_cap_zero(cap);

	dma_cap_set(DMA_SLAVE, cap);



	return dma_request_channel(cap, coh901318_filter_base_and_id, &args);

}

/*

 * DMA channel allocation

 */
@@ -2735,12 +2765,19 @@ static int __init coh901318_probe(struct platform_device *pdev) 
	if (err)

		goto err_register_memcpy;



	err = of_dma_controller_register(pdev->dev.of_node, coh901318_xlate,

					 base);

	if (err)

		goto err_register_of_dma;



	platform_set_drvdata(pdev, base);

	dev_info(&pdev->dev, "Initialized COH901318 DMA on virtual base 0x%08x\n",

		(u32) base->virtbase);



	return err;



 err_register_of_dma:

	dma_async_device_unregister(&base->dma_memcpy);

 err_register_memcpy:

	dma_async_device_unregister(&base->dma_slave);

 err_register_slave:
@@ -2752,17 +2789,23 @@ static int coh901318_remove(struct platform_device *pdev) 
{

	struct coh901318_base *base = platform_get_drvdata(pdev);



	of_dma_controller_free(pdev->dev.of_node);

	dma_async_device_unregister(&base->dma_memcpy);

	dma_async_device_unregister(&base->dma_slave);

	coh901318_pool_destroy(&base->pool);

	return 0;

}



static const struct of_device_id coh901318_dt_match[] = {

	{ .compatible = "stericsson,coh901318" },

	{},

};



static struct platform_driver coh901318_driver = {

	.remove = coh901318_remove,

	.driver = {

		.name	= "coh901318",

		.of_match_table = coh901318_dt_match,

	},

};