[PATCH] dmaengine: dw-edma: fix endianess confusion

From: Arnd Bergmann
Date: Mon Jun 17 2019 - 09:23:35 EST


When building with 'make C=1', sparse reports an endianess bug:

drivers/dma/dw-edma/dw-edma-v0-debugfs.c:60:30: warning: cast removes address space of expression
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:86:24: warning: incorrect type in argument 1 (different address spaces)
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:86:24: expected void const volatile [noderef] <asn:2>*addr
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:86:24: got void *[assigned] ptr
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:86:24: warning: incorrect type in argument 1 (different address spaces)
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:86:24: expected void const volatile [noderef] <asn:2>*addr
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:86:24: got void *[assigned] ptr
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:86:24: warning: incorrect type in argument 1 (different address spaces)
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:86:24: expected void const volatile [noderef] <asn:2>*addr
drivers/dma/dw-edma/dw-edma-v0-debugfs.c:86:24: got void *[assigned] ptr

The current code is clearly wrong, as it passes an endian-swapped word
into a register function where it gets swapped again. I assume that this
was simply ported from a non-Linux OS, and the swap was done incorrectly.
Replace it with a cast to uintptr_t.

Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/dma/dw-edma/dw-edma-v0-core.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
index 97e3fd41c8a8..d670ebcc37b3 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -195,7 +195,7 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
struct dw_edma_v0_lli __iomem *lli;
struct dw_edma_v0_llp __iomem *llp;
u32 control = 0, i = 0;
- u64 sar, dar, addr;
+ uintptr_t sar, dar, addr;
int j;

lli = chunk->ll_region.vaddr;
@@ -214,11 +214,11 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
/* Transfer size */
SET_LL(&lli[i].transfer_size, child->sz);
/* SAR - low, high */
- sar = cpu_to_le64(child->sar);
+ sar = (uintptr_t)child->sar;
SET_LL(&lli[i].sar_low, lower_32_bits(sar));
SET_LL(&lli[i].sar_high, upper_32_bits(sar));
/* DAR - low, high */
- dar = cpu_to_le64(child->dar);
+ dar = (uintptr_t)child->dar;
SET_LL(&lli[i].dar_low, lower_32_bits(dar));
SET_LL(&lli[i].dar_high, upper_32_bits(dar));
i++;
@@ -232,7 +232,7 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
/* Channel control */
SET_LL(&llp->control, control);
/* Linked list - low, high */
- addr = cpu_to_le64(chunk->ll_region.paddr);
+ addr = (uintptr_t)chunk->ll_region.paddr;
SET_LL(&llp->llp_low, lower_32_bits(addr));
SET_LL(&llp->llp_high, upper_32_bits(addr));
}
@@ -262,7 +262,7 @@ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
SET_CH(dw, chan->dir, chan->id, ch_control1,
(DW_EDMA_V0_CCS | DW_EDMA_V0_LLE));
/* Linked list - low, high */
- llp = cpu_to_le64(chunk->ll_region.paddr);
+ llp = (uintptr_t)chunk->ll_region.paddr;
SET_CH(dw, chan->dir, chan->id, llp_low, lower_32_bits(llp));
SET_CH(dw, chan->dir, chan->id, llp_high, upper_32_bits(llp));
}
--
2.20.0