On Mon, Sep 12, 2011 at 11:59:23PM +0530, Thomas Abraham wrote:
> 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.
>
> Cc: Jassi Brar <jassisinghbrar@xxxxxxxxx>
> Cc: Boojin Kim <boojin.kim@xxxxxxxxxxx>
> Signed-off-by: Thomas Abraham <thomas.abraham@xxxxxxxxxx>
> Reviewed-by: Rob Herring <rob.herring@xxxxxxxxxxx>
> ---
> .../devicetree/bindings/dma/arm-pl330.txt | 29 +++++++++++++++++
> drivers/dma/pl330.c | 33 +++++++++++++++++--
> 2 files changed, 58 insertions(+), 4 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/dma/arm-pl330.txt
>
> diff --git a/Documentation/devicetree/bindings/dma/arm-pl330.txt b/Documentation/devicetree/bindings/dma/arm-pl330.txt
> new file mode 100644
> index 0000000..05b007d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/arm-pl330.txt
> @@ -0,0 +1,29 @@
> +* 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: (from Samsung's Exynos4 processor dtsi file)
> +
> + 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.
> +
> + Example: tx-dma-channel = <&pdma0 12>;
Looks good to me. You may want to specify that the property name
should be in the form: <name>-dma-channel just to enforce a bit of
convention on the users.
> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> index 992bf82..7a4ebf1 100644
> --- a/drivers/dma/pl330.c
> +++ b/drivers/dma/pl330.c
> @@ -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)));
Don't open code this. There is already a function to decode a phandle
property. of_parse_phandle() should do the trick.
Otherwise looks good to me.
g.
> + }
> +#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;
> @@ -874,10 +894,15 @@ 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;
> --
> 1.6.6.rc2
>
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