[PATCH RFC 6/9] iommu/io-pgtable-arm-v7s: 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 ARMv7s 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-v7s.c |   90 ++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index 1d92ac948db7..8665dabb753b 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -545,6 +545,95 @@ static int arm_v7s_map(struct io_pgtable_ops *ops, unsigned long iova,
 	return ret;
 }
 
+static int arm_v7s_map_by_pgsize(struct io_pgtable_ops *ops,
+				 unsigned long iova, phys_addr_t paddr,
+				 size_t size, int prot, gfp_t gfp,
+				 size_t *mapped)
+{
+	struct arm_v7s_io_pgtable *data = io_pgtable_ops_to_data(ops);
+	struct io_pgtable *iop = &data->iop;
+	struct io_pgtable_cfg *cfg = &iop->cfg;
+	unsigned int min_pagesz = 1 << __ffs(cfg->pgsize_bitmap);
+	int ret;
+	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 (WARN_ON((iova + size - 1) >= (1ULL << cfg->ias) ||
+		    (paddr + size - 1) >= (1ULL << cfg->oas)))
+		return -ERANGE;
+
+	while (size) {
+		pgsize = iommu_pgsize(cfg->pgsize_bitmap, iova | paddr, size);
+		ret = __arm_v7s_map(data, iova, paddr, pgsize, prot, 1,
+				    data->pgd, gfp);
+
+		if (iop->cfg.quirks & IO_PGTABLE_QUIRK_TLBI_ON_MAP) {
+			io_pgtable_tlb_flush_walk(&data->iop, iova, size,
+						  ARM_V7S_BLOCK_SIZE(2));
+		} else {
+			wmb();
+		}
+
+		if (ret)
+			return ret;
+
+		iova += pgsize;
+		paddr += pgsize;
+		*mapped += pgsize;
+		size -= pgsize;
+	}
+
+	return 0;
+}
+
+static int arm_v7s_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_v7s_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_v7s_free_pgtable(struct io_pgtable *iop)
 {
 	struct arm_v7s_io_pgtable *data = io_pgtable_to_data(iop);
@@ -783,6 +872,7 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
 
 	data->iop.ops = (struct io_pgtable_ops) {
 		.map		= arm_v7s_map,
+		.map_sg		= arm_v7s_map_sg,
 		.unmap		= arm_v7s_unmap,
 		.iova_to_phys	= arm_v7s_iova_to_phys,
 	};


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