msm: iommu: Add functions to map/unmap an address range

Implement the iommu_map_range / iommu_unmap_range ops in
the MSM IOMMU driver.

Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
diff --git a/arch/arm/mach-msm/iommu.c b/arch/arm/mach-msm/iommu.c
index 2f74f8f..c9d8a86 100644
--- a/arch/arm/mach-msm/iommu.c
+++ b/arch/arm/mach-msm/iommu.c
@@ -22,6 +22,7 @@
 #include <linux/slab.h>
 #include <linux/iommu.h>
 #include <linux/clk.h>
+#include <linux/scatterlist.h>
 
 #include <asm/cacheflush.h>
 #include <asm/sizes.h>
@@ -111,6 +112,37 @@
 	return ret;
 }
 
+static int __flush_iotlb(struct iommu_domain *domain)
+{
+	struct msm_priv *priv = domain->priv;
+	struct msm_iommu_drvdata *iommu_drvdata;
+	struct msm_iommu_ctx_drvdata *ctx_drvdata;
+	int ret = 0;
+	int asid;
+
+	list_for_each_entry(ctx_drvdata, &priv->list_attached, attached_elm) {
+		if (!ctx_drvdata->pdev || !ctx_drvdata->pdev->dev.parent)
+			BUG();
+
+		iommu_drvdata = dev_get_drvdata(ctx_drvdata->pdev->dev.parent);
+		if (!iommu_drvdata)
+			BUG();
+
+		ret = __enable_clocks(iommu_drvdata);
+		if (ret)
+			goto fail;
+
+		asid = GET_CONTEXTIDR_ASID(iommu_drvdata->base,
+					   ctx_drvdata->num);
+
+		SET_TLBIASID(iommu_drvdata->base, ctx_drvdata->num, asid);
+		mb();
+		__disable_clocks(iommu_drvdata);
+	}
+fail:
+	return ret;
+}
+
 static void __reset_context(void __iomem *base, int ctx)
 {
 	SET_BPRCOSH(base, ctx, 0);
@@ -374,6 +406,32 @@
 	spin_unlock_irqrestore(&msm_iommu_lock, flags);
 }
 
+static int __get_pgprot(int prot, int len)
+{
+	unsigned int pgprot;
+	int tex, sh;
+
+	sh = (prot & MSM_IOMMU_ATTR_SH) ? 1 : 0;
+	tex = msm_iommu_tex_class[prot & MSM_IOMMU_CP_MASK];
+
+	if (tex < 0 || tex > NUM_TEX_CLASS - 1)
+		return 0;
+
+	if (len == SZ_16M || len == SZ_1M) {
+		pgprot = sh ? FL_SHARED : 0;
+		pgprot |= tex & 0x01 ? FL_BUFFERABLE : 0;
+		pgprot |= tex & 0x02 ? FL_CACHEABLE : 0;
+		pgprot |= tex & 0x04 ? FL_TEX0 : 0;
+	} else	{
+		pgprot = sh ? SL_SHARED : 0;
+		pgprot |= tex & 0x01 ? SL_BUFFERABLE : 0;
+		pgprot |= tex & 0x02 ? SL_CACHEABLE : 0;
+		pgprot |= tex & 0x04 ? SL_TEX0 : 0;
+	}
+
+	return pgprot;
+}
+
 static int msm_iommu_map(struct iommu_domain *domain, unsigned long va,
 			 phys_addr_t pa, int order, int prot)
 {
@@ -387,18 +445,10 @@
 	unsigned long sl_offset;
 	unsigned int pgprot;
 	size_t len = 0x1000UL << order;
-	int ret = 0, tex, sh;
+	int ret = 0;
 
 	spin_lock_irqsave(&msm_iommu_lock, flags);
 
-	sh = (prot & MSM_IOMMU_ATTR_SH) ? 1 : 0;
-	tex = msm_iommu_tex_class[prot & MSM_IOMMU_CP_MASK];
-
-	if (tex < 0 || tex > NUM_TEX_CLASS - 1) {
-		ret = -EINVAL;
-		goto fail;
-	}
-
 	priv = domain->priv;
 	if (!priv) {
 		ret = -EINVAL;
@@ -420,16 +470,11 @@
 		goto fail;
 	}
 
-	if (len == SZ_16M || len == SZ_1M) {
-		pgprot = sh ? FL_SHARED : 0;
-		pgprot |= tex & 0x01 ? FL_BUFFERABLE : 0;
-		pgprot |= tex & 0x02 ? FL_CACHEABLE : 0;
-		pgprot |= tex & 0x04 ? FL_TEX0 : 0;
-	} else	{
-		pgprot = sh ? SL_SHARED : 0;
-		pgprot |= tex & 0x01 ? SL_BUFFERABLE : 0;
-		pgprot |= tex & 0x02 ? SL_CACHEABLE : 0;
-		pgprot |= tex & 0x04 ? SL_TEX0 : 0;
+	pgprot = __get_pgprot(prot, len);
+
+	if (!pgprot) {
+		ret = -EINVAL;
+		goto fail;
 	}
 
 	fl_offset = FL_OFFSET(va);	/* Upper 12 bits */
@@ -626,6 +671,170 @@
 	return ret;
 }
 
+static int msm_iommu_map_range(struct iommu_domain *domain, unsigned int va,
+			       struct scatterlist *sg, unsigned int len,
+			       int prot)
+{
+	unsigned int pa;
+	unsigned int offset = 0;
+	unsigned int pgprot;
+	unsigned long *fl_table;
+	unsigned long *fl_pte;
+	unsigned long fl_offset;
+	unsigned long *sl_table;
+	unsigned long sl_offset, sl_start;
+	unsigned long flags;
+	unsigned int chunk_offset = 0;
+	unsigned int chunk_pa;
+	int ret = 0;
+	struct msm_priv *priv;
+
+	spin_lock_irqsave(&msm_iommu_lock, flags);
+
+	BUG_ON(len & (SZ_4K - 1));
+
+	priv = domain->priv;
+	fl_table = priv->pgtable;
+
+	pgprot = __get_pgprot(prot, SZ_4K);
+
+	if (!pgprot) {
+		ret = -EINVAL;
+		goto fail;
+	}
+
+	fl_offset = FL_OFFSET(va);	/* Upper 12 bits */
+	fl_pte = fl_table + fl_offset;	/* int pointers, 4 bytes */
+
+	sl_table = (unsigned long *) __va(((*fl_pte) & FL_BASE_MASK));
+	sl_offset = SL_OFFSET(va);
+
+	chunk_pa = sg_phys(sg);
+
+	while (offset < len) {
+		/* Set up a 2nd level page table if one doesn't exist */
+		if (*fl_pte == 0) {
+			sl_table = (unsigned long *)
+				 __get_free_pages(GFP_ATOMIC, get_order(SZ_4K));
+
+			if (!sl_table) {
+				pr_debug("Could not allocate second level table\n");
+				ret = -ENOMEM;
+				goto fail;
+			}
+
+			memset(sl_table, 0, SZ_4K);
+			*fl_pte = ((((int)__pa(sl_table)) & FL_BASE_MASK) |
+							    FL_TYPE_TABLE);
+			clean_pte(fl_pte, fl_pte + 1);
+		} else
+			sl_table = (unsigned long *)
+					       __va(((*fl_pte) & FL_BASE_MASK));
+
+		/* Keep track of initial position so we
+		 * don't clean more than we have to
+		 */
+		sl_start = sl_offset;
+
+		/* Build the 2nd level page table */
+		while (offset < len && sl_offset < NUM_SL_PTE) {
+			pa = chunk_pa + chunk_offset;
+			sl_table[sl_offset] = (pa & SL_BASE_MASK_SMALL) |
+					      pgprot | SL_AP0 | SL_AP1 | SL_NG |
+					      SL_SHARED | SL_TYPE_SMALL;
+			sl_offset++;
+			offset += SZ_4K;
+
+			chunk_offset += SZ_4K;
+
+			if (chunk_offset >= sg->length && offset < len) {
+				chunk_offset = 0;
+				sg = sg_next(sg);
+				chunk_pa = sg_phys(sg);
+			}
+		}
+
+		clean_pte(sl_table + sl_start, sl_table + sl_offset);
+
+		fl_pte++;
+		sl_offset = 0;
+	}
+	__flush_iotlb(domain);
+fail:
+	spin_unlock_irqrestore(&msm_iommu_lock, flags);
+	return ret;
+}
+
+
+static int msm_iommu_unmap_range(struct iommu_domain *domain, unsigned int va,
+				 unsigned int len)
+{
+	unsigned int offset = 0;
+	unsigned long *fl_table;
+	unsigned long *fl_pte;
+	unsigned long fl_offset;
+	unsigned long *sl_table;
+	unsigned long sl_start, sl_end;
+	unsigned long flags;
+	int used, i;
+	struct msm_priv *priv;
+
+	spin_lock_irqsave(&msm_iommu_lock, flags);
+
+	BUG_ON(len & (SZ_4K - 1));
+
+	priv = domain->priv;
+	fl_table = priv->pgtable;
+
+	fl_offset = FL_OFFSET(va);	/* Upper 12 bits */
+	fl_pte = fl_table + fl_offset;	/* int pointers, 4 bytes */
+
+	sl_start = SL_OFFSET(va);
+
+	while (offset < len) {
+		sl_table = (unsigned long *) __va(((*fl_pte) & FL_BASE_MASK));
+		sl_end = ((len - offset) / SZ_4K) + sl_start;
+
+		if (sl_end > NUM_SL_PTE)
+			sl_end = NUM_SL_PTE;
+
+		memset(sl_table + sl_start, 0, (sl_end - sl_start) * 4);
+		clean_pte(sl_table + sl_start, sl_table + sl_end);
+
+		offset += (sl_end - sl_start) * SZ_4K;
+
+		/* Unmap and free the 2nd level table if all mappings in it
+		 * were removed. This saves memory, but the table will need
+		 * to be re-allocated the next time someone tries to map these
+		 * VAs.
+		 */
+		used = 0;
+
+		/* If we just unmapped the whole table, don't bother
+		 * seeing if there are still used entries left.
+		 */
+		if (sl_end - sl_start != NUM_SL_PTE)
+			for (i = 0; i < NUM_SL_PTE; i++)
+				if (sl_table[i]) {
+					used = 1;
+					break;
+				}
+		if (!used) {
+			free_page((unsigned long)sl_table);
+			*fl_pte = 0;
+
+			clean_pte(fl_pte, fl_pte + 1);
+		}
+
+		sl_start = 0;
+		fl_pte++;
+	}
+
+	__flush_iotlb(domain);
+	spin_unlock_irqrestore(&msm_iommu_lock, flags);
+	return 0;
+}
+
 static phys_addr_t msm_iommu_iova_to_phys(struct iommu_domain *domain,
 					  unsigned long va)
 {
@@ -754,6 +963,8 @@
 	.detach_dev = msm_iommu_detach_dev,
 	.map = msm_iommu_map,
 	.unmap = msm_iommu_unmap,
+	.map_range = msm_iommu_map_range,
+	.unmap_range = msm_iommu_unmap_range,
 	.iova_to_phys = msm_iommu_iova_to_phys,
 	.domain_has_cap = msm_iommu_domain_has_cap
 };