[PATCH 4.4 130/137] net: davinci_cpdma: use dma_addr_t for DMA address

Greg Kroah-Hartman
2020-01-02T22:38:58Z

From: Arnd Bergmann <arnd@arndb.de>

commit 84092996673211f16ef3b942a191d7952e9dfea9 upstream.

The davinci_cpdma mixes up physical addresses as seen from the CPU
and DMA addresses as seen from a DMA master, since it can operate
on both normal memory or an on-chip buffer. If dma_addr_t is
different from phys_addr_t, this means we get a compile-time warning
about the type mismatch:

ethernet/ti/davinci_cpdma.c: In function 'cpdma_desc_pool_create':
ethernet/ti/davinci_cpdma.c:182:48: error: passing argument 3 of 'dma_alloc_coherent' from incompatible pointer type [-Werror=incompatible-pointer-types]
pool->cpumap = dma_alloc_coherent(dev, size, &pool->phys,
In file included from ethernet/ti/davinci_cpdma.c:21:0:
dma-mapping.h:398:21: note: expected 'dma_addr_t * {aka long long unsigned int *}' but argument is of type 'phys_addr_t * {aka unsigned int *}'
static inline void *dma_alloc_coherent(struct device *dev, size_t size,

This slightly restructures the code so the address we use for
mapping RAM into a DMA address is always a dma_addr_t, avoiding
the warning. The code is correct even if both types are 32-bit
because the DMA master in this device only supports 32-bit addressing
anyway, independent of the types that are used.

We still assign this value to pool->phys, and that is wrong if
the driver is ever used with an IOMMU, but that value appears to
be never used, so there is no problem really. I've added a couple
of comments about where we do things that are slightly violating
the API.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/ti/davinci_cpdma.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -82,7 +82,7 @@ struct cpdma_desc {

struct cpdma_desc_pool {
phys_addr_t phys;
- u32 hw_addr;
+ dma_addr_t hw_addr;
void __iomem *iomap; /* ioremap map */
void *cpumap; /* dma_alloc map */
int desc_size, mem_size;
@@ -152,7 +152,7 @@ struct cpdma_chan {
* abstract out these details
*/
static struct cpdma_desc_pool *
-cpdma_desc_pool_create(struct device *dev, u32 phys, u32 hw_addr,
+cpdma_desc_pool_create(struct device *dev, u32 phys, dma_addr_t hw_addr,
int size, int align)
{
int bitmap_size;
@@ -176,13 +176,13 @@ cpdma_desc_pool_create(struct device *de

if (phys) {
pool->phys = phys;
- pool->iomap = ioremap(phys, size);
+ pool->iomap = ioremap(phys, size); /* should be memremap? */
pool->hw_addr = hw_addr;
} else {
- pool->cpumap = dma_alloc_coherent(dev, size, &pool->phys,
+ pool->cpumap = dma_alloc_coherent(dev, size, &pool->hw_addr,
GFP_KERNEL);
- pool->iomap = pool->cpumap;
- pool->hw_addr = pool->phys;
+ pool->iomap = (void __iomem __force *)pool->cpumap;
+ pool->phys = pool->hw_addr; /* assumes no IOMMU, don't use this value */
}

if (pool->iomap)