[PATCH v2 01/11] dmaengine: dw-axi-dmac: fix reading register when runtime suspended

Jisheng Zhang
2023-04-15T10:48:09Z

We should runtime resume the device before calling
axi_chan_is_hw_enable(), otherwise we may see cpu aborts when
accessing registers in axi_chan_is_hw_enable().

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
index 7f3a60e28e38..23a10dbdecb7 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
@@ -462,13 +462,17 @@ static void dw_axi_dma_synchronize(struct dma_chan *dchan)

static int dma_chan_alloc_chan_resources(struct dma_chan *dchan)
{
+ int ret;
struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);

+ pm_runtime_get(chan->chip->dev);
+
/* ASSERT: channel is idle */
if (axi_chan_is_hw_enable(chan)) {
dev_err(chan2dev(chan), "%s is non-idle!\n",
axi_chan_name(chan));
- return -EBUSY;
+ ret = -EBUSY;
+ goto err_busy;
}

/* LLI address must be aligned to a 64-byte boundary */
@@ -478,13 +482,16 @@ static int dma_chan_alloc_chan_resources(struct dma_chan *dchan)
64, 0);
if (!chan->desc_pool) {
dev_err(chan2dev(chan), "No memory for descriptors\n");
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto err_busy;
}
dev_vdbg(dchan2dev(dchan), "%s: allocating\n", axi_chan_name(chan));

- pm_runtime_get(chan->chip->dev);
-
return 0;
+
+err_busy:
+ pm_runtime_put(chan->chip->dev);
+ return ret;
}

static void dma_chan_free_chan_resources(struct dma_chan *dchan)
--
2.39.2