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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jie Hai <haijie1@huawei.com>,
        Zhou Wang <wangzhou1@hisilicon.com>,
        Vinod Koul <vkoul@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 614/913] dmaengine: hisi_dma: fix MSI allocate fail when reload hisi_dma
Date:   Tue,  5 Apr 2022 09:27:56 +0200
Message-Id: <20220405070358.246404084@linuxfoundation.org>
In-Reply-To: <20220405070339.801210740@linuxfoundation.org>
References: <20220405070339.801210740@linuxfoundation.org>
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From: Jie Hai <haijie1@huawei.com>

[ 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@huawei.com>
Acked-by: Zhou Wang <wangzhou1@hisilicon.com>
Link: https://lore.kernel.org/r/20220216072101.34473-1-haijie1@huawei.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 c855a0e4f9ff..f680e9b40bf7 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
 
-- 
2.34.1