[PATCH 5/8 v4] dma: k3dma: Add support for dma-channel-mask

John Stultz
2019-01-16T17:11:16Z

From: Li Yu <liyu65@hisilicon.com>

Add dma-channel-mask as a property for k3dma, it defines
available dma channels which a non-secure mode driver can use.

One sample usage of this is in Hi3660 SoC. DMA channel 0 is
reserved to lpm3, which is a coprocessor for power management. So
as a result, any request in kernel (which runs on main processor
and in non-secure mode) should start from at least channel 1.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Tanglei Han <hantanglei@huawei.com>
Cc: Zhuangluan Su <suzhuangluan@hisilicon.com>
Cc: Ryan Grachek <ryan@edited.us>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Guodong Xu <guodong.xu@linaro.org>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Li Yu <liyu65@hisilicon.com>
[jstultz: Reworked to use a channel mask]
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v3: Rename to hisi-dma-avail-chan
v4: Rename to dma-channel-mask
---
drivers/dma/k3dma.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/k3dma.c b/drivers/dma/k3dma.c
index b2060bf..ed19b1f 100644
--- a/drivers/dma/k3dma.c
+++ b/drivers/dma/k3dma.c
@@ -111,6 +111,7 @@ struct k3_dma_dev {
struct dma_pool *pool;
u32 dma_channels;
u32 dma_requests;
+ u32 dma_channel_mask;
unsigned int irq;
};

@@ -318,6 +319,9 @@ 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++) {
+ if (!(d->dma_channel_mask & (1<<pch)))
+ continue;
+
p = &d->phy[pch];

if (p->vchan == NULL && !list_empty(&d->chan_pending)) {
@@ -335,6 +339,9 @@ static void k3_dma_tasklet(unsigned long arg)
spin_unlock_irq(&d->lock);

for (pch = 0; pch < d->dma_channels; pch++) {
+ if (!(d->dma_channel_mask & (1<<pch)))
+ continue;
+
if (pch_alloc & (1 << pch)) {
p = &d->phy[pch];
c = p->vchan;
@@ -855,6 +862,13 @@ 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);
+ ret = of_property_read_u32((&op->dev)->of_node,
+ "dma-channel-mask", &d->dma_channel_mask);
+ if (ret) {
+ dev_warn(&op->dev,
+ "dma-channel-mask doesn't exist, considering all as available.\n");
+ d->dma_channel_mask = (u32)~0UL;
+ }
}

if (!(soc_data->flags & K3_FLAG_NOCLK)) {
@@ -886,8 +900,12 @@ static int k3_dma_probe(struct platform_device *op)
return -ENOMEM;

for (i = 0; i < d->dma_channels; i++) {
- struct k3_dma_phy *p = &d->phy[i];
+ struct k3_dma_phy *p;
+
+ if (!(d->dma_channel_mask & (1<<i)))
+ continue;

+ p = &d->phy[i];
p->idx = i;
p->base = d->base + i * 0x40;
}
--
2.7.4