[PATCHv5 2/4] iovmm: add superpages support to fixed da address

From: Fernando Guzman Lugo
Date: Mon Oct 25 2010 - 14:39:44 EST


This patch adds superpages support to fixed ad address
inside iommu_kmap function.

Signed-off-by: Fernando Guzman Lugo <x0095840@xxxxxx>
---
arch/arm/plat-omap/iovmm.c | 62 +++++++++++++++++++++++++------------------
1 files changed, 36 insertions(+), 26 deletions(-)

diff --git a/arch/arm/plat-omap/iovmm.c b/arch/arm/plat-omap/iovmm.c
index 34f0012..93a34d9 100644
--- a/arch/arm/plat-omap/iovmm.c
+++ b/arch/arm/plat-omap/iovmm.c
@@ -87,35 +87,43 @@ static size_t sgtable_len(const struct sg_table *sgt)
}
#define sgtable_ok(x) (!!sgtable_len(x))

+static unsigned max_alignment(u32 addr)
+{
+ int i;
+ unsigned pagesize[] = { SZ_16M, SZ_1M, SZ_64K, SZ_4K, };
+ for (i = 0; i < ARRAY_SIZE(pagesize) && addr & (pagesize[i] - 1); i++)
+ ;
+ return (i < ARRAY_SIZE(pagesize)) ? pagesize[i] : 0;
+}
+
/*
* calculate the optimal number sg elements from total bytes based on
* iommu superpages
*/
-static unsigned int sgtable_nents(size_t bytes)
+static unsigned sgtable_nents(size_t bytes, u32 da, u32 pa)
{
- int i;
- unsigned int nr_entries;
- const unsigned long pagesize[] = { SZ_16M, SZ_1M, SZ_64K, SZ_4K, };
+ unsigned nr_entries = 0, ent_sz;

if (!IS_ALIGNED(bytes, PAGE_SIZE)) {
pr_err("%s: wrong size %08x\n", __func__, bytes);
return 0;
}

- nr_entries = 0;
- for (i = 0; i < ARRAY_SIZE(pagesize); i++) {
- if (bytes >= pagesize[i]) {
- nr_entries += (bytes / pagesize[i]);
- bytes %= pagesize[i];
- }
+ while (bytes) {
+ ent_sz = max_alignment(da | pa);
+ ent_sz = min_t(unsigned, ent_sz, iopgsz_max(bytes));
+ nr_entries++;
+ da += ent_sz;
+ pa += ent_sz;
+ bytes -= ent_sz;
}
- BUG_ON(bytes);

return nr_entries;
}

/* allocate and initialize sg_table header(a kind of 'superblock') */
-static struct sg_table *sgtable_alloc(const size_t bytes, u32 flags)
+static struct sg_table *sgtable_alloc(const size_t bytes, u32 flags,
+ u32 da, u32 pa)
{
unsigned int nr_entries;
int err;
@@ -127,9 +135,8 @@ static struct sg_table *sgtable_alloc(const size_t bytes, u32 flags)
if (!IS_ALIGNED(bytes, PAGE_SIZE))
return ERR_PTR(-EINVAL);

- /* FIXME: IOVMF_DA_FIXED should support 'superpages' */
- if ((flags & IOVMF_LINEAR) && (flags & IOVMF_DA_ANON)) {
- nr_entries = sgtable_nents(bytes);
+ if (flags & IOVMF_LINEAR) {
+ nr_entries = sgtable_nents(bytes, da, pa);
if (!nr_entries)
return ERR_PTR(-EINVAL);
} else
@@ -409,7 +416,8 @@ static inline void sgtable_drain_vmalloc(struct sg_table *sgt)
BUG_ON(!sgt);
}

-static void sgtable_fill_kmalloc(struct sg_table *sgt, u32 pa, size_t len)
+static void sgtable_fill_kmalloc(struct sg_table *sgt, u32 pa, u32 da,
+ size_t len)
{
unsigned int i;
struct scatterlist *sg;
@@ -418,9 +426,10 @@ static void sgtable_fill_kmalloc(struct sg_table *sgt, u32 pa, size_t len)
va = phys_to_virt(pa);

for_each_sg(sgt->sgl, sg, sgt->nents, i) {
- size_t bytes;
+ unsigned bytes;

- bytes = iopgsz_max(len);
+ bytes = max_alignment(da | pa);
+ bytes = min_t(unsigned, bytes, iopgsz_max(len));

BUG_ON(!iopgsz_ok(bytes));

@@ -429,6 +438,7 @@ static void sgtable_fill_kmalloc(struct sg_table *sgt, u32 pa, size_t len)
* 'pa' is cotinuous(linear).
*/
pa += bytes;
+ da += bytes;
len -= bytes;
}
BUG_ON(len);
@@ -695,18 +705,18 @@ u32 iommu_vmalloc(struct iommu *obj, u32 da, size_t bytes, u32 flags)
if (!va)
return -ENOMEM;

- sgt = sgtable_alloc(bytes, flags);
+ flags &= IOVMF_HW_MASK;
+ flags |= IOVMF_DISCONT;
+ flags |= IOVMF_ALLOC;
+ flags |= (da ? IOVMF_DA_FIXED : IOVMF_DA_ANON);
+
+ sgt = sgtable_alloc(bytes, flags, da, 0);
if (IS_ERR(sgt)) {
da = PTR_ERR(sgt);
goto err_sgt_alloc;
}
sgtable_fill_vmalloc(sgt, va);

- flags &= IOVMF_HW_MASK;
- flags |= IOVMF_DISCONT;
- flags |= IOVMF_ALLOC;
- flags |= (da ? IOVMF_DA_FIXED : IOVMF_DA_ANON);
-
da = __iommu_vmap(obj, da, sgt, va, bytes, flags);
if (IS_ERR_VALUE(da))
goto err_iommu_vmap;
@@ -746,11 +756,11 @@ static u32 __iommu_kmap(struct iommu *obj, u32 da, u32 pa, void *va,
{
struct sg_table *sgt;

- sgt = sgtable_alloc(bytes, flags);
+ sgt = sgtable_alloc(bytes, flags, da, pa);
if (IS_ERR(sgt))
return PTR_ERR(sgt);

- sgtable_fill_kmalloc(sgt, pa, bytes);
+ sgtable_fill_kmalloc(sgt, pa, da, bytes);

da = map_iommu_region(obj, da, sgt, va, bytes, flags);
if (IS_ERR_VALUE(da)) {
--
1.6.3.3

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