diff options
| author | Gavin Shan <gwshan@linux.vnet.ibm.com> | 2014-09-30 12:39:10 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2014-09-30 17:15:20 +1000 |
| commit | fe7e85c6f5ff63a8cd081deb35e58a0bd47589cd (patch) | |
| tree | 65edbf090dcf8da262a0c729d126f50c15ed0823 /arch/powerpc/platforms/powernv/setup.c | |
| parent | 372fb80db93af5d85c750515526d731856e1890c (diff) | |
powerpc/powernv: Override dma_get_required_mask()
The dma_get_required_mask() function is used by some drivers to
query the platform about what DMA mask is needed to cover all of
memory. This is a bit of a strange semantic when we have to choose
between IOMMU translation or bypass, but essentially what it means
is "what DMA mask will give best performances".
Currently, our IOMMU backend always returns a 32-bit mask here, we
don't do anything special to it when we have bypass available. This
causes some drivers to choose a 32-bit mask, thus losing the ability
to use the bypass window, thinking this is more efficient. The problem
was reported from the driver of following device:
0004:03:00.0 0107: 1000:0087 (rev 05)
0004:03:00.0 Serial Attached SCSI controller: LSI Logic / Symbios \
Logic SAS2308 PCI-Express Fusion-MPT SAS-2 (rev 05)
This patch adds an override of that function in order to, instead,
return a 64-bit mask whenever a bypass window is available in order
for drivers to prefer this configuration.
Reported-by: Murali N. Iyer <mniyer@us.ibm.com>
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/platforms/powernv/setup.c')
| -rw-r--r-- | arch/powerpc/platforms/powernv/setup.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c index bb1fc9b8d55e..3f9546d8a51f 100644 --- a/arch/powerpc/platforms/powernv/setup.c +++ b/arch/powerpc/platforms/powernv/setup.c @@ -173,6 +173,14 @@ static int pnv_dma_set_mask(struct device *dev, u64 dma_mask) return __dma_set_mask(dev, dma_mask); } +static u64 pnv_dma_get_required_mask(struct device *dev) +{ + if (dev_is_pci(dev)) + return pnv_pci_dma_get_required_mask(to_pci_dev(dev)); + + return __dma_get_required_mask(dev); +} + static void pnv_shutdown(void) { /* Let the PCI code clear up IODA tables */ @@ -335,6 +343,7 @@ define_machine(powernv) { .power_save = power7_idle, .calibrate_decr = generic_calibrate_decr, .dma_set_mask = pnv_dma_set_mask, + .dma_get_required_mask = pnv_dma_get_required_mask, #ifdef CONFIG_KEXEC .kexec_cpu_down = pnv_kexec_cpu_down, #endif |