Getting ready for the MSI interrupts. The pending_tre_count is used
in the interrupt handler to make sure all outstanding requests are
serviced.
The driver will allocate 11 MSI interrupts. Each MSI interrupt can be
assigned to a different CPU. Then, we have a race condition for common
variables as they share the same interrupt handler with a different
cause bit and they can potentially be executed in parallel. Making this
variable atomic so that it can be updated from multiple processor
contexts.
Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
---
drivers/dma/qcom/hidma.h | 2 +-
drivers/dma/qcom/hidma_dbg.c | 3 ++-
drivers/dma/qcom/hidma_ll.c | 13 ++++++-------
3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/dma/qcom/hidma.h b/drivers/dma/qcom/hidma.h
index de61764..181f7e0 100644
--- a/drivers/dma/qcom/hidma.h
+++ b/drivers/dma/qcom/hidma.h
@@ -59,7 +59,7 @@ struct hidma_lldev {
void __iomem *evca; /* Event Channel address */
struct hidma_tre
**pending_tre_list; /* Pointers to pending TREs */
- s32 pending_tre_count; /* Number of TREs pending */
+ atomic_t pending_tre_count; /* Number of TREs pending */
void *tre_ring; /* TRE ring */
dma_addr_t tre_dma; /* TRE ring to be shared with HW */
diff --git a/drivers/dma/qcom/hidma_dbg.c b/drivers/dma/qcom/hidma_dbg.c
index 3d83b99..3bdcb80 100644
--- a/drivers/dma/qcom/hidma_dbg.c
+++ b/drivers/dma/qcom/hidma_dbg.c
@@ -74,7 +74,8 @@ static void hidma_ll_devstats(struct seq_file *s, void *llhndl)
seq_printf(s, "tre_ring_handle=%pap\n", &lldev->tre_dma);
seq_printf(s, "tre_ring_size = 0x%x\n", lldev->tre_ring_size);
seq_printf(s, "tre_processed_off = 0x%x\n", lldev->tre_processed_off);
- seq_printf(s, "pending_tre_count=%d\n", lldev->pending_tre_count);
+ seq_printf(s, "pending_tre_count=%d\n",
+ atomic_read(&lldev->pending_tre_count));
seq_printf(s, "evca=%p\n", lldev->evca);
seq_printf(s, "evre_ring=%p\n", lldev->evre_ring);
seq_printf(s, "evre_ring_handle=%pap\n", &lldev->evre_dma);
diff --git a/drivers/dma/qcom/hidma_ll.c b/drivers/dma/qcom/hidma_ll.c
index e605c90..114409e 100644
--- a/drivers/dma/qcom/hidma_ll.c
+++ b/drivers/dma/qcom/hidma_ll.c
@@ -218,10 +218,9 @@ static int hidma_post_completed(struct hidma_lldev *lldev, int tre_iterator,
* Keep track of pending TREs that SW is expecting to receive
* from HW. We got one now. Decrement our counter.
*/
- lldev->pending_tre_count--;
- if (lldev->pending_tre_count < 0) {
+ if (atomic_dec_return(&lldev->pending_tre_count) < 0) {
dev_warn(lldev->dev, "tre count mismatch on completion");
- lldev->pending_tre_count = 0;
+ atomic_set(&lldev->pending_tre_count, 0);
}
spin_unlock_irqrestore(&lldev->lock, flags);
@@ -328,7 +327,7 @@ void hidma_cleanup_pending_tre(struct hidma_lldev *lldev, u8 err_info,
u32 tre_read_off;
tre_iterator = lldev->tre_processed_off;
- while (lldev->pending_tre_count) {
+ while (atomic_read(&lldev->pending_tre_count)) {
if (hidma_post_completed(lldev, tre_iterator, err_info,
err_code))
break;
@@ -555,7 +554,7 @@ void hidma_ll_queue_request(struct hidma_lldev *lldev, u32 tre_ch)
tre->err_code = 0;
tre->err_info = 0;
tre->queued = 1;
- lldev->pending_tre_count++;
+ atomic_inc(&lldev->pending_tre_count);
lldev->tre_write_offset = (lldev->tre_write_offset + HIDMA_TRE_SIZE)
% lldev->tre_ring_size;
spin_unlock_irqrestore(&lldev->lock, flags);
@@ -650,7 +649,7 @@ int hidma_ll_setup(struct hidma_lldev *lldev)
u32 val;
u32 nr_tres = lldev->nr_tres;
- lldev->pending_tre_count = 0;
+ atomic_set(&lldev->pending_tre_count, 0);
lldev->tre_processed_off = 0;
lldev->evre_processed_off = 0;
lldev->tre_write_offset = 0;
@@ -831,7 +830,7 @@ int hidma_ll_uninit(struct hidma_lldev *lldev)
tasklet_kill(&lldev->task);
memset(lldev->trepool, 0, required_bytes);
lldev->trepool = NULL;
- lldev->pending_tre_count = 0;
+ atomic_set(&lldev->pending_tre_count, 0);
lldev->tre_write_offset = 0;
rc = hidma_ll_reset(lldev);
--
1.9.1
--
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