On 22-06-18, 11:24, Guodong Xu wrote:
> From: Li Yu <liy...@hisilicon.com>
>
> On k3 series of SoC, DMA controller reserves some channels for
> other on-chip coprocessors. By adding support to dma_min_chan, kernel
> will not be able to use these reserved channels.
>
> One example is on Hi3660 platform, channel 0 is reserved to lpm3.
>
> Please also refer to Documentation/devicetree/bindings/dma/k3dma.txt
and if some other platform has channel X marked for co-processor, maybe
a last channel or something in middle, how will this work then?
I am thinking this should be a mask, rather than min.
>
> Signed-off-by: Li Yu <liy...@hisilicon.com>
> Signed-off-by: Guodong Xu <guodong...@linaro.org>
> ---
> drivers/dma/k3dma.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/dma/k3dma.c b/drivers/dma/k3dma.c
> index fa31cccbe04f..13cec12742e3 100644
> --- a/drivers/dma/k3dma.c
> +++ b/drivers/dma/k3dma.c
> @@ -113,6 +113,7 @@ struct k3_dma_dev {
> struct dma_pool *pool;
> u32 dma_channels;
> u32 dma_requests;
> + u32 dma_min_chan;
> unsigned int irq;
> };
>
> @@ -309,7 +310,7 @@ static void k3_dma_tasklet(unsigned long arg)
>
> /* check new channel request in d->chan_pending */
> spin_lock_irq(&d->lock);
> - for (pch = 0; pch < d->dma_channels; pch++) {
> + for (pch = d->dma_min_chan; pch < d->dma_channels; pch++) {
> p = &d->phy[pch];
>
> if (p->vchan == NULL && !list_empty(&d->chan_pending)) {
> @@ -326,7 +327,7 @@ static void k3_dma_tasklet(unsigned long arg)
> }
> spin_unlock_irq(&d->lock);
>
> - for (pch = 0; pch < d->dma_channels; pch++) {
> + for (pch = d->dma_min_chan; pch < d->dma_channels; pch++) {
> if (pch_alloc & (1 << pch)) {
> p = &d->phy[pch];
> c = p->vchan;
> @@ -825,6 +826,8 @@ static int k3_dma_probe(struct platform_device *op)
> "dma-channels", &d->dma_channels);
> of_property_read_u32((&op->dev)->of_node,
> "dma-requests", &d->dma_requests);
> + of_property_read_u32((&op->dev)->of_node,
> + "dma-min-chan", &d->dma_min_chan);
> }
>
> d->clk = devm_clk_get(&op->dev, NULL);
> @@ -848,12 +851,12 @@ static int k3_dma_probe(struct platform_device *op)
> return -ENOMEM;
>
> /* init phy channel */
> - d->phy = devm_kcalloc(&op->dev,
> - d->dma_channels, sizeof(struct k3_dma_phy), GFP_KERNEL);
> + d->phy = devm_kcalloc(&op->dev, (d->dma_channels - d->dma_min_chan),
> + sizeof(struct k3_dma_phy), GFP_KERNEL);
> if (d->phy == NULL)
> return -ENOMEM;
>
> - for (i = 0; i < d->dma_channels; i++) {
> + for (i = d->dma_min_chan; i < d->dma_channels; i++) {
> struct k3_dma_phy *p = &d->phy[i];
>
> p->idx = i;
> --
> 2.17.1
--
~Vinod
