2015-04-14 07:05:48

by Rameshwar Sahu

[permalink] [raw]
Subject: [PATCH] dmaengine: xgene-dma: Fix sparse wannings and coccinelle warnings

This patch fixes compilation sparse warnings like incorrect type in assignment
(different base types), cast to restricted __le64, symbol
'__UNIQUE_ID_author__COUNTER__' has multiple initializers etc and
coccinelle warnings (No need to set .owner here. The core will do it.)

This patch is based on slave-dma / for-linus branch.
(commit: 9f2fd0dfa594d857fbdaeda523ff7a46f16567f5 [26/28]
dmaengine: Add support for APM X-Gene SoC DMA engine driver)

Reported-by: kbuild test robot <[email protected]>
Signed-off-by: Rameshwar Prasad Sahu <[email protected]>
---
drivers/dma/xgene-dma.c | 44 +++++++++++++++++++++-----------------------
1 file changed, 21 insertions(+), 23 deletions(-)

diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
index aa61935..59f95db 100755
--- a/drivers/dma/xgene-dma.c
+++ b/drivers/dma/xgene-dma.c
@@ -238,10 +238,10 @@
dev_err(chan->dev, "%s: " fmt, chan->name, ##arg)

struct xgene_dma_desc_hw {
- u64 m0;
- u64 m1;
- u64 m2;
- u64 m3;
+ __le64 m0;
+ __le64 m1;
+ __le64 m2;
+ __le64 m3;
};

enum xgene_dma_ring_cfgsize {
@@ -388,12 +388,12 @@ static bool is_pq_enabled(struct xgene_dma *pdma)
return !(val & XGENE_DMA_PQ_DISABLE_MASK);
}

-static void xgene_dma_cpu_to_le64(u64 *desc, int count)
+static void xgene_dma_cpu_to_le64(struct xgene_dma_desc_hw *desc)
{
- int i;
-
- for (i = 0; i < count; i++)
- desc[i] = cpu_to_le64(desc[i]);
+ desc->m0 = cpu_to_le64(((u64 *)desc)[0]);
+ desc->m1 = cpu_to_le64(((u64 *)desc)[1]);
+ desc->m2 = cpu_to_le64(((u64 *)desc)[2]);
+ desc->m3 = cpu_to_le64(((u64 *)desc)[3]);
}

static u16 xgene_dma_encode_len(u32 len)
@@ -499,9 +499,9 @@ static void xgene_dma_prep_cpy_desc(struct xgene_dma_chan *chan,

skip_additional_src:
/* Hardware stores descriptor in little endian format */
- xgene_dma_cpu_to_le64(desc1, 4);
+ xgene_dma_cpu_to_le64(desc1);
if (desc2)
- xgene_dma_cpu_to_le64(desc2, 4);
+ xgene_dma_cpu_to_le64(desc2);
}

static void xgene_dma_prep_xor_desc(struct xgene_dma_chan *chan,
@@ -540,8 +540,8 @@ static void xgene_dma_prep_xor_desc(struct xgene_dma_chan *chan,
}

/* Hardware stores descriptor in little endian format */
- xgene_dma_cpu_to_le64(desc1, 4);
- xgene_dma_cpu_to_le64(desc2, 4);
+ xgene_dma_cpu_to_le64(desc1);
+ xgene_dma_cpu_to_le64(desc2);

/* Update meta data */
*nbytes = len;
@@ -1895,9 +1895,9 @@ static int xgene_dma_get_resources(struct platform_device *pdev,

pdma->csr_dma = devm_ioremap(&pdev->dev, res->start,
resource_size(res));
- if (IS_ERR(pdma->csr_dma)) {
+ if (!pdma->csr_dma) {
dev_err(&pdev->dev, "Failed to ioremap csr region");
- return PTR_ERR(pdma->csr_dma);
+ return -ENOMEM;
}

/* Get DMA ring csr region */
@@ -1909,9 +1909,9 @@ static int xgene_dma_get_resources(struct platform_device *pdev,

pdma->csr_ring = devm_ioremap(&pdev->dev, res->start,
resource_size(res));
- if (IS_ERR(pdma->csr_ring)) {
+ if (!pdma->csr_ring) {
dev_err(&pdev->dev, "Failed to ioremap ring csr region");
- return PTR_ERR(pdma->csr_ring);
+ return -ENOMEM;
}

/* Get DMA ring cmd csr region */
@@ -1923,9 +1923,9 @@ static int xgene_dma_get_resources(struct platform_device *pdev,

pdma->csr_ring_cmd = devm_ioremap(&pdev->dev, res->start,
resource_size(res));
- if (IS_ERR(pdma->csr_ring_cmd)) {
+ if (!pdma->csr_ring_cmd) {
dev_err(&pdev->dev, "Failed to ioremap ring cmd csr region");
- return PTR_ERR(pdma->csr_ring_cmd);
+ return -ENOMEM;
}

/* Get efuse csr region */
@@ -1937,9 +1937,9 @@ static int xgene_dma_get_resources(struct platform_device *pdev,

pdma->csr_efuse = devm_ioremap(&pdev->dev, res->start,
resource_size(res));
- if (IS_ERR(pdma->csr_efuse)) {
+ if (!pdma->csr_efuse) {
dev_err(&pdev->dev, "Failed to ioremap efuse csr region");
- return PTR_ERR(pdma->csr_efuse);
+ return -ENOMEM;
}

/* Get DMA error interrupt */
@@ -2076,7 +2076,6 @@ static struct platform_driver xgene_dma_driver = {
.remove = xgene_dma_remove,
.driver = {
.name = "X-Gene-DMA",
- .owner = THIS_MODULE,
.of_match_table = xgene_dma_of_match_ptr,
},
};
@@ -2085,6 +2084,5 @@ module_platform_driver(xgene_dma_driver);

MODULE_DESCRIPTION("APM X-Gene SoC DMA driver");
MODULE_AUTHOR("Rameshwar Prasad Sahu <[email protected]>");
-MODULE_AUTHOR("Loc Ho <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.0");
--
1.8.2.1


2015-04-14 08:43:51

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [PATCH] dmaengine: xgene-dma: Fix sparse wannings and coccinelle warnings

On Tuesday 14 April 2015 12:34:00 Rameshwar Prasad Sahu wrote:
> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
> index aa61935..59f95db 100755
> --- a/drivers/dma/xgene-dma.c
> +++ b/drivers/dma/xgene-dma.c
> @@ -238,10 +238,10 @@
> dev_err(chan->dev, "%s: " fmt, chan->name, ##arg)
>
> struct xgene_dma_desc_hw {
> - u64 m0;
> - u64 m1;
> - u64 m2;
> - u64 m3;
> + __le64 m0;
> + __le64 m1;
> + __le64 m2;
> + __le64 m3;
> };

This part looks good.

> enum xgene_dma_ring_cfgsize {
> @@ -388,12 +388,12 @@ static bool is_pq_enabled(struct xgene_dma *pdma)
> return !(val & XGENE_DMA_PQ_DISABLE_MASK);
> }
>
> -static void xgene_dma_cpu_to_le64(u64 *desc, int count)
> +static void xgene_dma_cpu_to_le64(struct xgene_dma_desc_hw *desc)
> {
> - int i;
> -
> - for (i = 0; i < count; i++)
> - desc[i] = cpu_to_le64(desc[i]);
> + desc->m0 = cpu_to_le64(((u64 *)desc)[0]);
> + desc->m1 = cpu_to_le64(((u64 *)desc)[1]);
> + desc->m2 = cpu_to_le64(((u64 *)desc)[2]);
> + desc->m3 = cpu_to_le64(((u64 *)desc)[3]);
> }

This part does not: you are circumventing the checks that are supposed
to help you here, and make things harder to read in the process.

> static u16 xgene_dma_encode_len(u32 len)
> @@ -499,9 +499,9 @@ static void xgene_dma_prep_cpy_desc(struct xgene_dma_chan *chan,
>
> skip_additional_src:
> /* Hardware stores descriptor in little endian format */
> - xgene_dma_cpu_to_le64(desc1, 4);
> + xgene_dma_cpu_to_le64(desc1);
> if (desc2)
> - xgene_dma_cpu_to_le64(desc2, 4);
> + xgene_dma_cpu_to_le64(desc2);
> }
>
> static void xgene_dma_prep_xor_desc(struct xgene_dma_chan *chan,
> @@ -540,8 +540,8 @@ static void xgene_dma_prep_xor_desc(struct xgene_dma_chan *chan,
> }
>
> /* Hardware stores descriptor in little endian format */
> - xgene_dma_cpu_to_le64(desc1, 4);
> - xgene_dma_cpu_to_le64(desc2, 4);
> + xgene_dma_cpu_to_le64(desc1);
> + xgene_dma_cpu_to_le64(desc2);
>
> /* Update meta data */
> *nbytes = len;

All these calls should just be removed, and the accesses to the descriptor
get changed to be little-endian. You can use the opportunity to remove
a lot of the macros that make the code harder to understand, and open-code
them like this:

diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
index aa61935ee706..3e3854559ecc 100755
--- a/drivers/dma/xgene-dma.c
+++ b/drivers/dma/xgene-dma.c
@@ -446,12 +446,12 @@ static void *xgene_dma_lookup_ext8(u64 *desc, int idx)
return (idx % 2) ? (desc + idx - 1) : (desc + idx + 1);
}

-static void xgene_dma_init_desc(void *desc, u16 dst_ring_num)
+static void xgene_dma_init_desc(struct xgene_dma_desc_hw *desc, u16 dst_ring_num)
{
- XGENE_DMA_DESC_C_SET(desc); /* Coherent IO */
- XGENE_DMA_DESC_IN_SET(desc);
- XGENE_DMA_DESC_H0ENQ_NUM_SET(desc, dst_ring_num);
- XGENE_DMA_DESC_RTYPE_SET(desc, XGENE_DMA_RING_OWNER_DMA);
+ desc->m1 |= cpu_to_le64(XGENE_DMA_DESC_C_BIT);
+ desc->m0 |= cpu_to_le64(XGENE_DMA_DESC_IN_BIT);
+ desc->m3 |= cpu_to_le64(dst_ring_num << XGENE_DMA_DESC_HOENQ_NUM_POS);
+ desc->m0 |= cpu_to_le64(dst_ring_num << XGENE_DMA_RING_OWNER_DMA);
}


which will store the descriptors in the right format with correct endianess,
make use of the sparse checking and let the reader see what's actually
going on.

Arnd