On Tue, Aug 01, 2017 at 06:20:43PM +0800, Hanjun Guo wrote: > Hi Lorenzo, > > On 2017/7/31 23:23, Lorenzo Pieralisi wrote: > >IORT named components provide firmware configuration describing > >how many address bits a given device is capable of generating > >to address memory. > > > >Add code to the kernel to retrieve memory address limits > >configuration for IORT named components and configure DMA masks > >accordingly. > > > >Signed-off-by: Lorenzo Pieralisi <[email protected]> > >Cc: Will Deacon <[email protected]> > >Cc: Robin Murphy <[email protected]> > >Cc: Nate Watterson <[email protected]> > >--- > > drivers/acpi/arm64/iort.c | 40 ++++++++++++++++++++++++++++++---------- > > 1 file changed, 30 insertions(+), 10 deletions(-) > > > >diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c > >index 67b85ae..b85d19f 100644 > >--- a/drivers/acpi/arm64/iort.c > >+++ b/drivers/acpi/arm64/iort.c > >@@ -680,6 +680,24 @@ static const struct iommu_ops *iort_iommu_xlate(struct > >device *dev, > > return ret ? NULL : ops; > > } > >+static int nc_dma_get_range(struct device *dev, u64 *size) > >+{ > >+ struct acpi_iort_node *node; > >+ struct acpi_iort_named_component *ncomp; > >+ > >+ node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT, > >+ iort_match_node_callback, dev); > >+ if (!node) > >+ return -ENODEV; > >+ > >+ ncomp = (struct acpi_iort_named_component *)node->node_data; > >+ > >+ *size = ncomp->memory_address_limit >= 64 ? ~0ULL : > >+ 1ULL<<ncomp->memory_address_limit; > > Just a question here, if the IORT table didn't configure this > value properly, will the device working properly? I'm asking this > because in the table of IORT of D05, this value is set to 0 so far > (SAS and network), but I can boot D05 OK with your patch set, not > sure if any further issues.
Then you wonder why I wrote it as a separate patch. Why is that value set to 0 (is that because that's the insane default ?) ? It is a firmware bug and if things work ok with this patch applied either this patch contains a bug or drivers override the DMA masks to cancel out this patch effects. Please fix the firmware. Thanks, Lorenzo
