On 11/23/2016 02:57 PM, James Bottomley wrote:
On Wed, 2016-11-23 at 13:29 -0800, Tushar Dave wrote:
qlogicpti uses '__u32' for dma handle while invoking kernel DMA APIs,
instead of using dma_addr_t. This hasn't caused any 'incompatible
pointer type' warning on SPARC because until now dma_addr_t is of
type u32. However, recent changes in SPARC ATU (iommu) enabled 64bit
DMA and therefore dma_addr_t became of type u64. This makes
'incompatible pointer type' warnings inevitable.
e.g.
drivers/scsi/qlogicpti.c: In function ‘qpti_map_queues’:
drivers/scsi/qlogicpti.c:813: warning: passing argument 3 of
‘dma_alloc_coherent’ from incompatible pointer type
./include/linux/dma-mapping.h:445: note: expected ‘dma_addr_t *’ but
argument is of type ‘__u32 *’
drivers/scsi/qlogicpti.c:822: warning: passing argument 3 of
‘dma_alloc_coherent’ from incompatible pointer type
./include/linux/dma-mapping.h:445: note: expected ‘dma_addr_t *’ but
argument is of type ‘__u32 *’
This patch resolves above compiler warnings.
There appears to be no point to the first three hunks of this diff:
(ushort)(x << 16)
(ushort)(x & 0xffff)
return the same thing whether the type of x is u32 or u64, so there was
no need to alter the original code.
Agree, will make the change.
What's the guarantee, since the device descriptors only cope with 32
bits of physical address, that this driver never gets any dma
address beyond its addressable range? Is it that the sbus can never
be attached to this ATU type IOMMU? If so, saying that in the log
would be useful.
Thanks for catching this.
As per my understanding, I think, all DMA map/unmap go through
ATU (iommu) in sun4v sparc. To guarantee that driver doesn't get DMA
address beyond its addressable range , driver must set dma mask before
requesting any DMA mapping!
I will investigate further and send v2.
Thanks for the review.
-Tushar
James
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