On 2020-11-19 06:18, Yong Wu wrote:
Add a granule_ignore option when tlb gather for some HW which don't care
about granule when it flush tlb.
Signed-off-by: Yong Wu <yong...@mediatek.com>
---
include/linux/iommu.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 794d4085edd3..1aad32238510 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -171,6 +171,7 @@ enum iommu_dev_features {
* @start: IOVA representing the start of the range to be flushed
* @end: IOVA representing the end of the range to be flushed (exclusive)
* @pgsize: The interval at which to perform the flush
+ * @granule_ignore: For tlb flushing that could be regardless of granule.
*
* This structure is intended to be updated by multiple calls to the
* ->unmap() function in struct iommu_ops before eventually being passed
@@ -180,6 +181,7 @@ struct iommu_iotlb_gather {
unsigned long start;
unsigned long end;
size_t pgsize;
+ bool granule_ignore;
I can't see that this would ever need to vary on a per-unmap-operation
basis, so this doesn't seem like the right level of abstraction. AFAICS
it should simply be hard-coded in the driver logic.
};
/**
@@ -544,7 +546,7 @@ static inline void iommu_iotlb_gather_add_page(struct
iommu_domain *domain,
* a different granularity, then sync the TLB so that the gather
* structure can be rewritten.
*/
- if (gather->pgsize != size ||
+ if ((!gather->granule_ignore && gather->pgsize != size) ||
I also think this is a slippery slope in the wrong direction anyway -
there is likely to be a fair bit of hardware-dependent variation around
how low-level TLB maintenance works (also consider drivers that may want
to convert a sufficiently large range to an "invalidate all" operation),
so if a generic helper function doesn't do the right thing for a given
driver, that driver should simply not use the helper, and directly
implement the logic it does need.
Robin.
end < gather->start || start > gather->end) {
if (gather->pgsize)
iommu_iotlb_sync(domain, gather);
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