[PATCH 5.17 0750/1126] dmaengine: hisi_dma: fix MSI allocate fail when reload hisi_dma

From: Greg Kroah-Hartman
Date: Tue Apr 05 2022 - 05:50:49 EST

From: Jie Hai <haijie1@xxxxxxxxxx>

[ Upstream commit b95044b38425f563404234d96bbb20cc6360c7e1 ]

Remove the loaded hisi_dma driver and reload it, the driver fails
to work properly. The following error is reported in the kernel log:

[ 1475.597609] hisi_dma 0000:7b:00.0: Failed to allocate MSI vectors!
[ 1475.604915] hisi_dma: probe of 0000:7b:00.0 failed with error -28

As noted in "The MSI Driver Guide HOWTO"[1], the number of MSI
interrupt must be a power of two. The Kunpeng DMA driver allocates 30
MSI interrupts. As a result, no space left on device is reported
when the driver is reloaded and allocates interrupt vectors from the
interrupt domain.

This patch changes the number of interrupt vectors allocated by
hisi_dma driver to 32 to avoid this problem.

[1] https://www.kernel.org/doc/html/latest/PCI/msi-howto.html

Fixes: e9f08b65250d ("dmaengine: hisilicon: Add Kunpeng DMA engine support")

Signed-off-by: Jie Hai <haijie1@xxxxxxxxxx>
Acked-by: Zhou Wang <wangzhou1@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220216072101.34473-1-haijie1@xxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/dma/hisi_dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/hisi_dma.c b/drivers/dma/hisi_dma.c
index 97c87a7cba87..43817ced3a3e 100644
--- a/drivers/dma/hisi_dma.c
+++ b/drivers/dma/hisi_dma.c
@@ -30,7 +30,7 @@
#define HISI_DMA_MODE 0x217c
#define HISI_DMA_OFFSET 0x100

-#define HISI_DMA_MSI_NUM 30
+#define HISI_DMA_MSI_NUM 32
#define HISI_DMA_CHAN_NUM 30
#define HISI_DMA_Q_DEPTH_VAL 1024