media: ipu6: optimize the IPU6 MMU unmapping flow

The MMU mapping flow is optimized for improve the performance, the
unmapping flow could also be optimized to follow same flow.

Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

drivers/media/pci/intel/ipu6/ipu6-mmu.c

@@ -257,44 +257,51 @@ static u32 *alloc_l2_pt(struct ipu6_mmu_info *mmu_info)
 static size_t l2_unmap(struct ipu6_mmu_info *mmu_info, unsigned long iova,
 		       phys_addr_t dummy, size_t size)
 {
-	u32 l1_idx = iova >> ISP_L1PT_SHIFT;
+	unsigned int l2_entries;
-	u32 iova_start = iova;
 	unsigned int l2_idx;
-	size_t unmapped = 0;
 	unsigned long flags;
+	u32 l1_idx;
 	u32 *l2_pt;
 
-	dev_dbg(mmu_info->dev, "unmapping l2 page table for l1 index %u (iova 0x%8.8lx)\n",
-		l1_idx, iova);
-
 	spin_lock_irqsave(&mmu_info->lock, flags);
-	if (mmu_info->l1_pt[l1_idx] == mmu_info->dummy_l2_pteval) {
+	for (l1_idx = iova >> ISP_L1PT_SHIFT;
-		spin_unlock_irqrestore(&mmu_info->lock, flags);
+	     size > 0 && l1_idx < ISP_L1PT_PTES; l1_idx++) {
-		dev_err(mmu_info->dev,
-			"unmap iova 0x%8.8lx l1 idx %u which was not mapped\n",
-			iova, l1_idx);
-		return 0;
-	}
-
-	for (l2_idx = (iova_start & ISP_L2PT_MASK) >> ISP_L2PT_SHIFT;
-	     (iova_start & ISP_L1PT_MASK) + (l2_idx << ISP_PAGE_SHIFT)
-		     < iova_start + size && l2_idx < ISP_L2PT_PTES; l2_idx++) {
-		phys_addr_t pteval;
-
-		l2_pt = mmu_info->l2_pts[l1_idx];
-		pteval = TBL_PHYS_ADDR(l2_pt[l2_idx]);
 		dev_dbg(mmu_info->dev,
-			"unmap l2 index %u with pteval 0x%p\n",
+			"unmapping l2 pgtable (l1 index %u (iova 0x%8.8lx))\n",
-			l2_idx, &pteval);
+			l1_idx, iova);
-		l2_pt[l2_idx] = mmu_info->dummy_page_pteval;
 
-		clflush_cache_range((void *)&l2_pt[l2_idx],
+		if (mmu_info->l1_pt[l1_idx] == mmu_info->dummy_l2_pteval) {
-				    sizeof(l2_pt[l2_idx]));
+			dev_err(mmu_info->dev,
-		unmapped++;
+				"unmap not mapped iova 0x%8.8lx l1 index %u\n",
+				iova, l1_idx);
+			continue;
+		}
+		l2_pt = mmu_info->l2_pts[l1_idx];
+
+		l2_entries = 0;
+		for (l2_idx = (iova & ISP_L2PT_MASK) >> ISP_L2PT_SHIFT;
+		     size > 0 && l2_idx < ISP_L2PT_PTES; l2_idx++) {
+			phys_addr_t pteval = TBL_PHYS_ADDR(l2_pt[l2_idx]);
+
+			dev_dbg(mmu_info->dev,
+				"unmap l2 index %u with pteval 0x%p\n",
+				l2_idx, &pteval);
+			l2_pt[l2_idx] = mmu_info->dummy_page_pteval;
+
+			iova += ISP_PAGE_SIZE;
+			size -= ISP_PAGE_SIZE;
+
+			l2_entries++;
+		}
+
+		WARN_ON_ONCE(!l2_entries);
+		clflush_cache_range(&l2_pt[l2_idx - l2_entries],
+				    sizeof(l2_pt[0]) * l2_entries);
 	}
-	spin_unlock_irqrestore(&mmu_info->lock, flags);
 
-	return unmapped << ISP_PAGE_SHIFT;
+	WARN_ON_ONCE(size);
+	spin_unlock_irqrestore(&mmu_info->lock, flags);
+	return l2_entries << ISP_PAGE_SHIFT;
 }
 
 static int l2_map(struct ipu6_mmu_info *mmu_info, unsigned long iova,
@@ -643,40 +650,13 @@ phys_addr_t ipu6_mmu_iova_to_phys(struct ipu6_mmu_info *mmu_info,
 	return phy_addr;
 }
 
-static size_t ipu6_mmu_pgsize(unsigned long pgsize_bitmap,
-			      unsigned long addr_merge, size_t size)
-{
-	unsigned int pgsize_idx;
-	size_t pgsize;
-
-	/* Max page size that still fits into 'size' */
-	pgsize_idx = __fls(size);
-
-	if (likely(addr_merge)) {
-		/* Max page size allowed by address */
-		unsigned int align_pgsize_idx = __ffs(addr_merge);
-
-		pgsize_idx = min(pgsize_idx, align_pgsize_idx);
-	}
-
-	pgsize = (1UL << (pgsize_idx + 1)) - 1;
-	pgsize &= pgsize_bitmap;
-
-	WARN_ON(!pgsize);
-
-	/* pick the biggest page */
-	pgsize_idx = __fls(pgsize);
-	pgsize = 1UL << pgsize_idx;
-
-	return pgsize;
-}
-
 size_t ipu6_mmu_unmap(struct ipu6_mmu_info *mmu_info, unsigned long iova,
 		      size_t size)
 {
-	size_t unmapped_page, unmapped = 0;
 	unsigned int min_pagesz;
 
+	dev_dbg(mmu_info->dev, "unmapping iova 0x%lx size 0x%zx\n", iova, size);
+
 	/* find out the minimum page size supported */
 	min_pagesz = 1 << __ffs(mmu_info->pgsize_bitmap);
 
@@ -688,29 +668,10 @@ size_t ipu6_mmu_unmap(struct ipu6_mmu_info *mmu_info, unsigned long iova,
 	if (!IS_ALIGNED(iova | size, min_pagesz)) {
 		dev_err(NULL, "unaligned: iova 0x%lx size 0x%zx min_pagesz 0x%x\n",
 			iova, size, min_pagesz);
-		return -EINVAL;
+		return 0;
 	}
 
-	/*
+	return __ipu6_mmu_unmap(mmu_info, iova, size);
-	 * Keep iterating until we either unmap 'size' bytes (or more)
-	 * or we hit an area that isn't mapped.
-	 */
-	while (unmapped < size) {
-		size_t pgsize = ipu6_mmu_pgsize(mmu_info->pgsize_bitmap,
-						iova, size - unmapped);
-
-		unmapped_page = __ipu6_mmu_unmap(mmu_info, iova, pgsize);
-		if (!unmapped_page)
-			break;
-
-		dev_dbg(mmu_info->dev, "unmapped: iova 0x%lx size 0x%zx\n",
-			iova, unmapped_page);
-
-		iova += unmapped_page;
-		unmapped += unmapped_page;
-	}
-
-	return unmapped;
 }
 
 int ipu6_mmu_map(struct ipu6_mmu_info *mmu_info, unsigned long iova,