Commit 84092996 authored Jan 29, 2016 by Arnd Bergmann Committed by David S. Miller Jan 29, 2016

net: davinci_cpdma: use dma_addr_t for DMA address

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>

parent 84922d8c

drivers/net/ethernet/ti/davinci_cpdma.c

+6 −6

Original line number	Diff line number	Diff line
		@@ -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 *dev, u32 phys, u32 hw_addr,

		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)