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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: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
hifive-unleashed-5.1
Linus Walleij 2013-04-19 13:42:55 +02:00
parent ba078d1bd4
commit faadc6e3d5
2 changed files with 75 additions and 0 deletions
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32
Documentation/devicetree/bindings/dma/ste-coh901318.txt 100644
View File

@ -0,0 +1,32 @@
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";
};

43
drivers/dma/coh901318.c
View File

@ -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,
},
};