[PATCH RFC 5/9] iommu/io-pgtable-arm: Hook up map_sg()

[Chuck Lever <chuck.lever@oracle.com>]

From: Isaac J. Manjarres <isaacm@codeaurora.org>

Implement the map_sg io-pgtable op for the ARM LPAE io-pgtable
code, so that IOMMU drivers can call it when they need to map
a scatter-gather list.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 drivers/iommu/io-pgtable-arm.c |   86 ++++++++++++++++++++++++++++++++++++++++
 drivers/iommu/iommu.c          |   12 +++---
 include/linux/iommu.h          |    8 ++++
 3 files changed, 101 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 87def58e79b5..0c11529442b8 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -473,6 +473,91 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
 	return ret;
 }
 
+static int arm_lpae_map_by_pgsize(struct io_pgtable_ops *ops,
+				  unsigned long iova, phys_addr_t paddr,
+				  size_t size, int iommu_prot, gfp_t gfp,
+				  size_t *mapped)
+{
+	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
+	struct io_pgtable_cfg *cfg = &data->iop.cfg;
+	arm_lpae_iopte *ptep = data->pgd;
+	int ret, lvl = data->start_level;
+	arm_lpae_iopte prot = arm_lpae_prot_to_pte(data, iommu_prot);
+	unsigned int min_pagesz = 1 << __ffs(cfg->pgsize_bitmap);
+	long iaext = (s64)(iova + size - 1) >> cfg->ias;
+	size_t pgsize;
+
+	if (!IS_ALIGNED(iova | paddr | size, min_pagesz)) {
+		pr_err("unaligned: iova 0x%lx pa %pa size 0x%zx min_pagesz 0x%x\n",
+		       iova, &paddr, size, min_pagesz);
+		return -EINVAL;
+	}
+
+	if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1)
+		iaext = ~iaext;
+	if (WARN_ON(iaext || (paddr + size - 1) >> cfg->oas))
+		return -ERANGE;
+
+	while (size) {
+		pgsize = iommu_pgsize(cfg->pgsize_bitmap, iova | paddr, size);
+		ret = __arm_lpae_map(data, iova, paddr, pgsize, prot, lvl, ptep,
+				     gfp);
+		if (ret)
+			return ret;
+
+		iova += pgsize;
+		paddr += pgsize;
+		*mapped += pgsize;
+		size -= pgsize;
+	}
+
+	return 0;
+}
+
+static int arm_lpae_map_sg(struct io_pgtable_ops *ops, unsigned long iova,
+			   struct scatterlist *sg, unsigned int nents,
+			   int iommu_prot, gfp_t gfp, size_t *mapped)
+{
+
+	size_t len = 0;
+	unsigned int i = 0;
+	int ret;
+	phys_addr_t start;
+
+	*mapped = 0;
+
+	/* If no access, then nothing to do */
+	if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))
+		return 0;
+
+	while (i <= nents) {
+		phys_addr_t s_phys = sg_phys(sg);
+
+		if (len && s_phys != start + len) {
+			ret = arm_lpae_map_by_pgsize(ops, iova + *mapped, start,
+						     len, iommu_prot, gfp,
+						     mapped);
+
+			if (ret)
+				return ret;
+
+			len = 0;
+		}
+
+		if (len) {
+			len += sg->length;
+		} else {
+			len = sg->length;
+			start = s_phys;
+		}
+
+		if (++i < nents)
+			sg = sg_next(sg);
+	}
+
+	return 0;
+}
+
 static void __arm_lpae_free_pgtable(struct arm_lpae_io_pgtable *data, int lvl,
 				    arm_lpae_iopte *ptep)
 {
@@ -750,6 +835,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
 
 	data->iop.ops = (struct io_pgtable_ops) {
 		.map		= arm_lpae_map,
+		.map_sg		= arm_lpae_map_sg,
 		.unmap		= arm_lpae_unmap,
 		.iova_to_phys	= arm_lpae_iova_to_phys,
 	};
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 3d099a31ddca..ed879a4d7fac 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2346,8 +2346,8 @@ phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
 }
 EXPORT_SYMBOL_GPL(iommu_iova_to_phys);
 
-static size_t iommu_pgsize(struct iommu_domain *domain,
-			   unsigned long addr_merge, size_t size)
+size_t iommu_pgsize(unsigned long pgsize_bitmap, unsigned long addr_merge,
+		    size_t size)
 {
 	unsigned int pgsize_idx;
 	size_t pgsize;
@@ -2366,7 +2366,7 @@ static size_t iommu_pgsize(struct iommu_domain *domain,
 	pgsize = (1UL << (pgsize_idx + 1)) - 1;
 
 	/* throw away page sizes not supported by the hardware */
-	pgsize &= domain->pgsize_bitmap;
+	pgsize &= pgsize_bitmap;
 
 	/* make sure we're still sane */
 	BUG_ON(!pgsize);
@@ -2412,7 +2412,8 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
 	pr_debug("map: iova 0x%lx pa %pa size 0x%zx\n", iova, &paddr, size);
 
 	while (size) {
-		size_t pgsize = iommu_pgsize(domain, iova | paddr, size);
+		size_t pgsize = iommu_pgsize(domain->pgsize_bitmap,
+					     iova | paddr, size);
 
 		pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
 			 iova, &paddr, pgsize);
@@ -2500,7 +2501,8 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
 	 * or we hit an area that isn't mapped.
 	 */
 	while (unmapped < size) {
-		size_t pgsize = iommu_pgsize(domain, iova, size - unmapped);
+		size_t pgsize = iommu_pgsize(domain->pgsize_bitmap, iova,
+					     size - unmapped);
 
 		unmapped_page = ops->unmap(domain, iova, pgsize, iotlb_gather);
 		if (!unmapped_page)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 9ce0aa9e236b..cd5f35022a25 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -439,6 +439,8 @@ extern int iommu_sva_unbind_gpasid(struct iommu_domain *domain,
 				   struct device *dev, ioasid_t pasid);
 extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
 extern struct iommu_domain *iommu_get_dma_domain(struct device *dev);
+extern size_t iommu_pgsize(unsigned long pgsize_bitmap, unsigned long addr_mer,
+			   size_t size);
 extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
 		     phys_addr_t paddr, size_t size, int prot);
 extern int iommu_map_atomic(struct iommu_domain *domain, unsigned long iova,
@@ -691,6 +693,12 @@ static inline struct iommu_domain *iommu_get_domain_for_dev(struct device *dev)
 	return NULL;
 }
 
+static inline size_t iommu_pgsize(unsigned long pgsize_bitmap,
+				  unsigned long addr_merge, size_t size)
+{
+	return 0;
+}
+
 static inline int iommu_map(struct iommu_domain *domain, unsigned long iova,
 			    phys_addr_t paddr, size_t size, int prot)
 {


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