Skip to content

Commit

Permalink
iommu/exynos: Remove ARM-specific cache flush interface
Browse files Browse the repository at this point in the history 
This patch replaces custom ARM-specific code for performing CPU cache flush
operations with generic code based on DMA-mapping. Domain managing code
is independent of particular SYSMMU device, so the first registered SYSMMU
device is used for DMA-mapping calls. This simplification works fine
because all SYSMMU controllers are in the same address space (where
DMA address equals physical address) and the DMA-mapping calls are done
mainly to flush CPU cache to make changes visible to SYSMMU controllers.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
  • Loading branch information
Marek Szyprowski authored and Joerg Roedel committed Feb 25, 2016
1 parent 58c6f6a commit 5e3435e
Showing 1 changed file with 49 additions and 25 deletions.
74 changes: 49 additions & 25 deletions drivers/iommu/exynos-iommu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,9 +27,6 @@
#include <linux/slab.h>
#include <linux/dma-iommu.h>

#include <asm/cacheflush.h>
#include <asm/pgtable.h>

typedef u32 sysmmu_iova_t;
typedef u32 sysmmu_pte_t;

Expand Down Expand Up @@ -83,6 +80,7 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)
return (iova >> SPAGE_ORDER) & (NUM_LV2ENTRIES - 1);
}

#define LV1TABLE_SIZE (NUM_LV1ENTRIES * sizeof(sysmmu_pte_t))
#define LV2TABLE_SIZE (NUM_LV2ENTRIES * sizeof(sysmmu_pte_t))

#define SPAGES_PER_LPAGE (LPAGE_SIZE / SPAGE_SIZE)
Expand Down Expand Up @@ -134,6 +132,7 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)

#define has_sysmmu(dev) (dev->archdata.iommu != NULL)

static struct device *dma_dev;
static struct kmem_cache *lv2table_kmem_cache;
static sysmmu_pte_t *zero_lv2_table;
#define ZERO_LV2LINK mk_lv1ent_page(virt_to_phys(zero_lv2_table))
Expand Down Expand Up @@ -650,16 +649,19 @@ static struct platform_driver exynos_sysmmu_driver __refdata = {
}
};

static inline void pgtable_flush(void *vastart, void *vaend)
static inline void update_pte(sysmmu_pte_t *ent, sysmmu_pte_t val)
{
dmac_flush_range(vastart, vaend);
outer_flush_range(virt_to_phys(vastart),
virt_to_phys(vaend));
dma_sync_single_for_cpu(dma_dev, virt_to_phys(ent), sizeof(*ent),
DMA_TO_DEVICE);
*ent = val;
dma_sync_single_for_device(dma_dev, virt_to_phys(ent), sizeof(*ent),
DMA_TO_DEVICE);
}

static struct iommu_domain *exynos_iommu_domain_alloc(unsigned type)
{
struct exynos_iommu_domain *domain;
dma_addr_t handle;
int i;


Expand Down Expand Up @@ -694,7 +696,10 @@ static struct iommu_domain *exynos_iommu_domain_alloc(unsigned type)
domain->pgtable[i + 7] = ZERO_LV2LINK;
}

pgtable_flush(domain->pgtable, domain->pgtable + NUM_LV1ENTRIES);
handle = dma_map_single(dma_dev, domain->pgtable, LV1TABLE_SIZE,
DMA_TO_DEVICE);
/* For mapping page table entries we rely on dma == phys */
BUG_ON(handle != virt_to_phys(domain->pgtable));

spin_lock_init(&domain->lock);
spin_lock_init(&domain->pgtablelock);
Expand Down Expand Up @@ -738,10 +743,18 @@ static void exynos_iommu_domain_free(struct iommu_domain *iommu_domain)
if (iommu_domain->type == IOMMU_DOMAIN_DMA)
iommu_put_dma_cookie(iommu_domain);

dma_unmap_single(dma_dev, virt_to_phys(domain->pgtable), LV1TABLE_SIZE,
DMA_TO_DEVICE);

for (i = 0; i < NUM_LV1ENTRIES; i++)
if (lv1ent_page(domain->pgtable + i))
if (lv1ent_page(domain->pgtable + i)) {
phys_addr_t base = lv2table_base(domain->pgtable + i);

dma_unmap_single(dma_dev, base, LV2TABLE_SIZE,
DMA_TO_DEVICE);
kmem_cache_free(lv2table_kmem_cache,
phys_to_virt(lv2table_base(domain->pgtable + i)));
phys_to_virt(base));
}

free_pages((unsigned long)domain->pgtable, 2);
free_pages((unsigned long)domain->lv2entcnt, 1);
Expand Down Expand Up @@ -834,11 +847,10 @@ static sysmmu_pte_t *alloc_lv2entry(struct exynos_iommu_domain *domain,
if (!pent)
return ERR_PTR(-ENOMEM);

*sent = mk_lv1ent_page(virt_to_phys(pent));
update_pte(sent, mk_lv1ent_page(virt_to_phys(pent)));
kmemleak_ignore(pent);
*pgcounter = NUM_LV2ENTRIES;
pgtable_flush(pent, pent + NUM_LV2ENTRIES);
pgtable_flush(sent, sent + 1);
dma_map_single(dma_dev, pent, LV2TABLE_SIZE, DMA_TO_DEVICE);

/*
* If pre-fetched SLPD is a faulty SLPD in zero_l2_table,
Expand Down Expand Up @@ -891,9 +903,7 @@ static int lv1set_section(struct exynos_iommu_domain *domain,
*pgcnt = 0;
}

*sent = mk_lv1ent_sect(paddr);

pgtable_flush(sent, sent + 1);
update_pte(sent, mk_lv1ent_sect(paddr));

spin_lock(&domain->lock);
if (lv1ent_page_zero(sent)) {
Expand All @@ -917,12 +927,15 @@ static int lv2set_page(sysmmu_pte_t *pent, phys_addr_t paddr, size_t size,
if (WARN_ON(!lv2ent_fault(pent)))
return -EADDRINUSE;

*pent = mk_lv2ent_spage(paddr);
pgtable_flush(pent, pent + 1);
update_pte(pent, mk_lv2ent_spage(paddr));
*pgcnt -= 1;
} else { /* size == LPAGE_SIZE */
int i;
dma_addr_t pent_base = virt_to_phys(pent);

dma_sync_single_for_cpu(dma_dev, pent_base,
sizeof(*pent) * SPAGES_PER_LPAGE,
DMA_TO_DEVICE);
for (i = 0; i < SPAGES_PER_LPAGE; i++, pent++) {
if (WARN_ON(!lv2ent_fault(pent))) {
if (i > 0)
Expand All @@ -932,7 +945,9 @@ static int lv2set_page(sysmmu_pte_t *pent, phys_addr_t paddr, size_t size,

*pent = mk_lv2ent_lpage(paddr);
}
pgtable_flush(pent - SPAGES_PER_LPAGE, pent);
dma_sync_single_for_device(dma_dev, pent_base,
sizeof(*pent) * SPAGES_PER_LPAGE,
DMA_TO_DEVICE);
*pgcnt -= SPAGES_PER_LPAGE;
}

Expand Down Expand Up @@ -1042,8 +1057,7 @@ static size_t exynos_iommu_unmap(struct iommu_domain *iommu_domain,
}

/* workaround for h/w bug in System MMU v3.3 */
*ent = ZERO_LV2LINK;
pgtable_flush(ent, ent + 1);
update_pte(ent, ZERO_LV2LINK);
size = SECT_SIZE;
goto done;
}
Expand All @@ -1064,9 +1078,8 @@ static size_t exynos_iommu_unmap(struct iommu_domain *iommu_domain,
}

if (lv2ent_small(ent)) {
*ent = 0;
update_pte(ent, 0);
size = SPAGE_SIZE;
pgtable_flush(ent, ent + 1);
domain->lv2entcnt[lv1ent_offset(iova)] += 1;
goto done;
}
Expand All @@ -1077,9 +1090,13 @@ static size_t exynos_iommu_unmap(struct iommu_domain *iommu_domain,
goto err;
}

dma_sync_single_for_cpu(dma_dev, virt_to_phys(ent),
sizeof(*ent) * SPAGES_PER_LPAGE,
DMA_TO_DEVICE);
memset(ent, 0, sizeof(*ent) * SPAGES_PER_LPAGE);
pgtable_flush(ent, ent + SPAGES_PER_LPAGE);

dma_sync_single_for_device(dma_dev, virt_to_phys(ent),
sizeof(*ent) * SPAGES_PER_LPAGE,
DMA_TO_DEVICE);
size = LPAGE_SIZE;
domain->lv2entcnt[lv1ent_offset(iova)] += SPAGES_PER_LPAGE;
done:
Expand Down Expand Up @@ -1261,6 +1278,13 @@ static int __init exynos_iommu_of_setup(struct device_node *np)
if (IS_ERR(pdev))
return PTR_ERR(pdev);

/*
* use the first registered sysmmu device for performing
* dma mapping operations on iommu page tables (cpu cache flush)
*/
if (!dma_dev)
dma_dev = &pdev->dev;

of_iommu_set_ops(np, &exynos_iommu_ops);
return 0;
}
Expand Down

0 comments on commit 5e3435e

Please sign in to comment.