iommu/io-pgtable: Add a domain attribute for pagetable configuration

Add a new iommu domain attribute DOMAIN_ATTR_IO_PGTABLE_CFG
for pagetable configuration which initially will be used to
set quirks like for system cache aka last level cache to be
used by client drivers like GPU to set right attributes for
caching the hardware pagetables into the system cache and
later can be extended to include other page table configuration
data.

Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Link: https://lore.kernel.org/r/9190aa16f378fc0a7f8e57b2b9f60b033e7eeb4f.1606287059.git.saiprakash.ranjan@codeaurora.org
Signed-off-by: Will Deacon <will@kernel.org>

include/linux/io-pgtable.h

@@ -208,6 +208,10 @@ struct io_pgtable {
 
 #define io_pgtable_ops_to_pgtable(x) container_of((x), struct io_pgtable, ops)
 
+struct io_pgtable_domain_attr {
+	unsigned long quirks;
+};
+
 static inline void io_pgtable_tlb_flush_all(struct io_pgtable *iop)
 {
 	iop->cfg.tlb->tlb_flush_all(iop->cookie);

include/linux/iommu.h

@@ -118,6 +118,7 @@ enum iommu_attr {
 	DOMAIN_ATTR_FSL_PAMUV1,
 	DOMAIN_ATTR_NESTING,	/* two stages of translation */
 	DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE,
+	DOMAIN_ATTR_IO_PGTABLE_CFG,
 	DOMAIN_ATTR_MAX,
 };