Commit 93ed5544 authored by Thomas Abraham's avatar Thomas Abraham Committed by Kukjin Kim
Browse files

DMA: PL330: Add device tree support 



For PL330 dma controllers instantiated from device tree, the channel
lookup is based on phandle of the dma controller and dma request id
specified by the client node. During probe, the private data of each
channel of the controller is set to point to the device node of the
dma controller. The 'chan_id' of the each channel is used as the
dma request id.

Client driver requesting dma channels specify the phandle of the
dma controller and the request id. The pl330 filter function
converts the phandle to the device node pointer and matches that
with channel's private data. If a match is found, the request id
from the client node and the 'chan_id' of the channel is matched.
A channel is found if both the values match.

Acked-by: default avatarJassi Brar <jassisinghbrar@gmail.com>
Acked-by: default avatarBoojin Kim <boojin.kim@samsung.com>
Signed-off-by: default avatarThomas Abraham <thomas.abraham@linaro.org>
Reviewed-by: default avatarRob Herring <rob.herring@calxeda.com>
Acked-by: default avatarGrant Likely <grant.likely@secretlab.ca>
Acked-by: default avatarVinod Koul <vinod.koul@intel.com>
Signed-off-by: default avatarKukjin Kim <kgene.kim@samsung.com>
parent e1cd8454

Documentation/devicetree/bindings/dma/arm-pl330.txt

0 → 100644
+30 −0
Original line number Diff line number Diff line 
* ARM PrimeCell PL330 DMA Controller



The ARM PrimeCell PL330 DMA controller can move blocks of memory contents

between memory and peripherals or memory to memory.



Required properties:

  - compatible: should include both "arm,pl330" and "arm,primecell".

  - reg: physical base address of the controller and length of memory mapped

    region.

  - interrupts: interrupt number to the cpu.



Example:



	pdma0: pdma@12680000 {

		compatible = "arm,pl330", "arm,primecell";

		reg = <0x12680000 0x1000>;

		interrupts = <99>;

	};



Client drivers (device nodes requiring dma transfers from dev-to-mem or

mem-to-dev) should specify the DMA channel numbers using a two-value pair

as shown below.



  [property name]  = <[phandle of the dma controller] [dma request id]>;



      where 'dma request id' is the dma request number which is connected

      to the client controller. The 'property name' is recommended to be

      of the form <name>-dma-channel.



  Example:  tx-dma-channel = <&pdma0 12>;

drivers/dma/pl330.c

+29 −4
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/amba/pl330.h>

#include <linux/pm_runtime.h>

#include <linux/scatterlist.h>

#include <linux/of.h>



#define NR_DEFAULT_DESC	16
@@ -277,6 +278,20 @@ bool pl330_filter(struct dma_chan *chan, void *param) 
	if (chan->device->dev->driver != &pl330_driver.drv)

		return false;



#ifdef CONFIG_OF

	if (chan->device->dev->of_node) {

		const __be32 *prop_value;

		phandle phandle;

		struct device_node *node;



		prop_value = ((struct property *)param)->value;

		phandle = be32_to_cpup(prop_value++);

		node = of_find_node_by_phandle(phandle);

		return ((chan->private == node) &&

				(chan->chan_id == be32_to_cpup(prop_value)));

	}

#endif



	peri_id = chan->private;

	return *peri_id == (unsigned)param;

}
@@ -855,12 +870,17 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id) 
	INIT_LIST_HEAD(&pd->channels);



	/* Initialize channel parameters */

	num_chan = max(pdat ? pdat->nr_valid_peri : 0, (u8)pi->pcfg.num_chan);

	num_chan = max(pdat ? pdat->nr_valid_peri : (u8)pi->pcfg.num_peri,

			(u8)pi->pcfg.num_chan);

	pdmac->peripherals = kzalloc(num_chan * sizeof(*pch), GFP_KERNEL);



	for (i = 0; i < num_chan; i++) {

		pch = &pdmac->peripherals[i];

		if (!adev->dev.of_node)

			pch->chan.private = pdat ? &pdat->peri_id[i] : NULL;

		else

			pch->chan.private = adev->dev.of_node;



		INIT_LIST_HEAD(&pch->work_list);

		spin_lock_init(&pch->lock);

		pch->pl330_chid = NULL;
@@ -872,10 +892,15 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id) 
	}



	pd->dev = &adev->dev;

	if (pdat)

	if (pdat) {

		pd->cap_mask = pdat->cap_mask;

	else

	} else {

		dma_cap_set(DMA_MEMCPY, pd->cap_mask);

		if (pi->pcfg.num_peri) {

			dma_cap_set(DMA_SLAVE, pd->cap_mask);

			dma_cap_set(DMA_CYCLIC, pd->cap_mask);

		}

	}



	pd->device_alloc_chan_resources = pl330_alloc_chan_resources;

	pd->device_free_chan_resources = pl330_free_chan_resources;

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