This is a note to let you know that I've just added the patch titled
dmaengine: dw-edma: Fix the ch_count hdma callback
to the 6.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dmaengine-dw-edma-fix-the-ch_count-hdma-callback.patch
and it can be found in the queue-6.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 06acc988c3f7d9850858644cea7b73c5ad21e387
Author: Kory Maincent <kory.maincent@xxxxxxxxxxx>
Date: Mon Jan 29 17:25:57 2024 +0100
dmaengine: dw-edma: Fix the ch_count hdma callback
[ Upstream commit cd665bfc757c71e9b7e0abff0f362d8abd38a805 ]
The current check of ch_en enabled to know the maximum number of available
hardware channels is wrong as it check the number of ch_en register set
but all of them are unset at probe. This register is set at the
dw_hdma_v0_core_start function which is run lately before a DMA transfer.
The HDMA IP have no way to know the number of hardware channels available
like the eDMA IP, then let set it to maximum channels and let the platform
set the right number of channels.
Fixes: e74c39573d35 ("dmaengine: dw-edma: Add support for native HDMA")
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Reviewed-by: Serge Semin <fancer.lancer@xxxxxxxxx>
Signed-off-by: Kory Maincent <kory.maincent@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240129-b4-feature_hdma_mainline-v7-1-8e8c1acb7a46@xxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
index 00b735a0202ab..1f4cb7db54756 100644
--- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
@@ -65,18 +65,12 @@ static void dw_hdma_v0_core_off(struct dw_edma *dw)
static u16 dw_hdma_v0_core_ch_count(struct dw_edma *dw, enum dw_edma_dir dir)
{
- u32 num_ch = 0;
- int id;
-
- for (id = 0; id < HDMA_V0_MAX_NR_CH; id++) {
- if (GET_CH_32(dw, id, dir, ch_en) & BIT(0))
- num_ch++;
- }
-
- if (num_ch > HDMA_V0_MAX_NR_CH)
- num_ch = HDMA_V0_MAX_NR_CH;
-
- return (u16)num_ch;
+ /*
+ * The HDMA IP have no way to know the number of hardware channels
+ * available, we set it to maximum channels and let the platform
+ * set the right number of channels.
+ */
+ return HDMA_V0_MAX_NR_CH;
}
static enum dma_status dw_hdma_v0_core_ch_status(struct dw_edma_chan *chan)
