[PATCH 2/3] k3dma: add support to reserved minimum channels

[Guodong Xu]

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

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