[RFC PATCH v2 37/58] iommu/io-pgtable: Generalize walker interface

[Mostafa Saleh <smostafa@google.com>]

Add a common struct for walker, which has a callback visitor
with HW agnostic info (phys addr + size).

Add size to walker so it can walk a range of IOVAs.

Also, add a cookie for the arm walker.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 drivers/gpu/drm/msm/msm_iommu.c       |  5 +++-
 drivers/iommu/io-pgtable-arm-common.c | 35 ++++++++++++++++++---------
 include/linux/io-pgtable-arm.h        |  2 +-
 include/linux/io-pgtable.h            | 18 ++++++++++++--
 4 files changed, 45 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
index 3e692818ba1f..8516861dd626 100644
--- a/drivers/gpu/drm/msm/msm_iommu.c
+++ b/drivers/gpu/drm/msm/msm_iommu.c
@@ -200,6 +200,9 @@ msm_iommu_pagetable_walk(struct msm_mmu *mmu, unsigned long iova, uint64_t ptes[
 {
 	struct msm_iommu_pagetable *pagetable;
 	struct arm_lpae_io_pgtable_walk_data wd = {};
+	struct io_pgtable_walk_common walker = {
+		.data = &wd,
+	};
 
 	if (mmu->type != MSM_MMU_IOMMU_PAGETABLE)
 		return -EINVAL;
@@ -209,7 +212,7 @@ msm_iommu_pagetable_walk(struct msm_mmu *mmu, unsigned long iova, uint64_t ptes[
 	if (!pagetable->pgtbl_ops->pgtable_walk)
 		return -EINVAL;
 
-	pagetable->pgtbl_ops->pgtable_walk(pagetable->pgtbl_ops, iova, &wd);
+	pagetable->pgtbl_ops->pgtable_walk(pagetable->pgtbl_ops, iova, 1, &walker);
 
 	for (int i = 0; i < ARRAY_SIZE(wd.ptes); i++)
 		ptes[i] = wd.ptes[i];
diff --git a/drivers/iommu/io-pgtable-arm-common.c b/drivers/iommu/io-pgtable-arm-common.c
index 21ee8ff7c881..4fc0b03494e3 100644
--- a/drivers/iommu/io-pgtable-arm-common.c
+++ b/drivers/iommu/io-pgtable-arm-common.c
@@ -481,7 +481,8 @@ struct iova_to_phys_data {
 static int visit_iova_to_phys(struct io_pgtable_walk_data *walk_data, int lvl,
 			      arm_lpae_iopte *ptep, size_t size)
 {
-	struct iova_to_phys_data *data = walk_data->data;
+	struct io_pgtable_walk_common *walker = walk_data->data;
+	struct iova_to_phys_data *data = walker->data;
 	data->pte = *ptep;
 	data->lvl = lvl;
 	return 0;
@@ -492,8 +493,11 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
 {
 	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
 	struct iova_to_phys_data d;
-	struct io_pgtable_walk_data walk_data = {
+	struct io_pgtable_walk_common walker = {
 		.data = &d,
+	};
+	struct io_pgtable_walk_data walk_data = {
+		.data = &walker,
 		.visit = visit_iova_to_phys,
 		.addr = iova,
 		.end = iova + 1,
@@ -511,23 +515,25 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
 static int visit_pgtable_walk(struct io_pgtable_walk_data *walk_data, int lvl,
 			      arm_lpae_iopte *ptep, size_t size)
 {
-	struct arm_lpae_io_pgtable_walk_data *data = walk_data->data;
-	data->ptes[data->level++] = *ptep;
+	struct io_pgtable_walk_common *walker = walk_data->data;
+	struct arm_lpae_io_pgtable_walk_data *data = walker->data;
+
+	data->ptes[lvl] = *ptep;
+	data->level = lvl + 1;
 	return 0;
 }
 
-static int arm_lpae_pgtable_walk(struct io_pgtable_ops *ops, unsigned long iova, void *wd)
+static int arm_lpae_pgtable_walk(struct io_pgtable_ops *ops, unsigned long iova,
+				 size_t size, struct io_pgtable_walk_common *walker)
 {
 	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
 	struct io_pgtable_walk_data walk_data = {
-		.data = wd,
+		.data = walker,
 		.visit = visit_pgtable_walk,
 		.addr = iova,
-		.end = iova + 1,
+		.end = iova + size,
 	};
 
-	((struct arm_lpae_io_pgtable_walk_data *)wd)->level = 0;
-
 	return __arm_lpae_iopte_walk(data, &walk_data, data->pgd, data->start_level);
 }
 
@@ -537,6 +543,7 @@ static int io_pgtable_visit(struct arm_lpae_io_pgtable *data,
 {
 	struct io_pgtable *iop = &data->iop;
 	arm_lpae_iopte pte = READ_ONCE(*ptep);
+	struct io_pgtable_walk_common *walker = walk_data->data;
 
 	size_t size = ARM_LPAE_BLOCK_SIZE(lvl, data);
 	int ret = walk_data->visit(walk_data, lvl, ptep, size);
@@ -544,6 +551,8 @@ static int io_pgtable_visit(struct arm_lpae_io_pgtable *data,
 		return ret;
 
 	if (iopte_leaf(pte, lvl, iop->fmt)) {
+		if (walker->visit_leaf)
+			walker->visit_leaf(iopte_to_paddr(pte, data), size, walker, ptep);
 		walk_data->addr += size;
 		return 0;
 	}
@@ -585,7 +594,8 @@ static int __arm_lpae_iopte_walk(struct arm_lpae_io_pgtable *data,
 static int visit_dirty(struct io_pgtable_walk_data *walk_data, int lvl,
 		       arm_lpae_iopte *ptep, size_t size)
 {
-	struct iommu_dirty_bitmap *dirty = walk_data->data;
+	struct io_pgtable_walk_common *walker = walk_data->data;
+	struct iommu_dirty_bitmap *dirty = walker->data;
 
 	if (!iopte_leaf(*ptep, lvl, walk_data->iop->fmt))
 		return 0;
@@ -606,9 +616,12 @@ static int arm_lpae_read_and_clear_dirty(struct io_pgtable_ops *ops,
 {
 	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
 	struct io_pgtable_cfg *cfg = &data->iop.cfg;
+	struct io_pgtable_walk_common walker = {
+		.data = dirty,
+	};
 	struct io_pgtable_walk_data walk_data = {
 		.iop = &data->iop,
-		.data = dirty,
+		.data = &walker,
 		.visit = visit_dirty,
 		.flags = flags,
 		.addr = iova,
diff --git a/include/linux/io-pgtable-arm.h b/include/linux/io-pgtable-arm.h
index 88922314157d..9e5878c37d78 100644
--- a/include/linux/io-pgtable-arm.h
+++ b/include/linux/io-pgtable-arm.h
@@ -18,7 +18,7 @@ struct arm_lpae_io_pgtable {
 
 struct io_pgtable_walk_data {
 	struct io_pgtable		*iop;
-	void				*data;
+	struct io_pgtable_walk_common	*data;
 	int (*visit)(struct io_pgtable_walk_data *walk_data, int lvl,
 		     arm_lpae_iopte *ptep, size_t size);
 	unsigned long			flags;
diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index f789234c703b..da50e17b0177 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -185,12 +185,25 @@ struct io_pgtable_cfg {
  *
  * @ptes:     The recorded PTE values from the walk
  * @level:    The level of the last PTE
+ * @cookie:   Cookie set by caller to identify it
  *
  * @level also specifies the last valid index in @ptes
  */
 struct arm_lpae_io_pgtable_walk_data {
 	u64 ptes[4];
 	int level;
+	void *cookie;
+};
+
+/**
+ * struct io_pgtable_walk_common - common information from a pgtable walk
+ * @visit_leaf: callback for each leaf providing it's physical address and size
+ */
+struct io_pgtable_walk_common {
+	void (*visit_leaf)(phys_addr_t paddr, size_t size,
+			   struct io_pgtable_walk_common *data,
+			   void *wd);
+	void *data; /* pointer to walk data as arm_lpae_io_pgtable_walk_data*/
 };
 
 /**
@@ -199,7 +212,7 @@ struct arm_lpae_io_pgtable_walk_data {
  * @map_pages:    Map a physically contiguous range of pages of the same size.
  * @unmap_pages:  Unmap a range of virtually contiguous pages of the same size.
  * @iova_to_phys: Translate iova to physical address.
- * @pgtable_walk: (optional) Perform a page table walk for a given iova.
+ * @pgtable_walk: (optional) Perform a page table walk for a given iova and size.
  *
  * These functions map directly onto the iommu_ops member functions with
  * the same names.
@@ -213,7 +226,8 @@ struct io_pgtable_ops {
 			      struct iommu_iotlb_gather *gather);
 	phys_addr_t (*iova_to_phys)(struct io_pgtable_ops *ops,
 				    unsigned long iova);
-	int (*pgtable_walk)(struct io_pgtable_ops *ops, unsigned long iova, void *wd);
+	int (*pgtable_walk)(struct io_pgtable_ops *ops, unsigned long iova,
+			    size_t size, struct io_pgtable_walk_common *walker);
 	int (*read_and_clear_dirty)(struct io_pgtable_ops *ops,
 				    unsigned long iova, size_t size,
 				    unsigned long flags,
-- 
2.47.0.338.g60cca15819-goog