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DMA: PL330: Add device tree support

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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: Jassi Brar <jassisinghbrar@gmail.com>
Acked-by: Boojin Kim <boojin.kim@samsung.com>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Reviewed-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
This commit is contained in:
Thomas Abraham 2011-10-24 11:43:31 +02:00 committed by Kukjin Kim
parent e1cd8454da
commit 93ed554412
2 changed files with 59 additions and 4 deletions
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30
Documentation/devicetree/bindings/dma/arm-pl330.txt Normal file
View File

@ -0,0 +1,30 @@
* 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>;

33
drivers/dma/pl330.c
View File

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