[RFC 3/3] iommu: dma-iommu: use common implementation also on ARM architecture
Robin Murphy
robin.murphy at arm.com
Tue Mar 15 11:45:24 UTC 2016
Hi Magnus,
On 15/03/16 11:18, Magnus Damm wrote:
> Hi Marek,
>
> On Fri, Feb 19, 2016 at 5:22 PM, Marek Szyprowski
> <m.szyprowski at samsung.com> wrote:
>> This patch replaces ARM-specific IOMMU-based DMA-mapping implementation
>> with generic IOMMU DMA-mapping code shared with ARM64 architecture. The
>> side-effect of this change is a switch from bitmap-based IO address space
>> management to tree-based code. There should be no functional changes
>> for drivers, which rely on initialization from generic arch_setup_dna_ops()
>> interface. Code, which used old arm_iommu_* functions must be updated to
>> new interface.
>>
>> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
>> ---
>
> Thanks for your efforts and my apologies for late comments. Just FYI
> I'll try your patch (and this series) with the ipmmu-vmsa.c driver on
> 32-bit ARM and see how it goes. Nice not to have to support multiple
> interfaces depending on architecture!
>
> One question that comes to mind is how to handle features.
>
> For instance, the 32-bit ARM code supports DMA_ATTR_FORCE_CONTIGUOUS
> while the shared code in drivers/iommu/dma-iommu.c does not. I assume
> existing users may rely on such features so from my point of view it
> probably makes sense to carry over features from the 32-bit ARM code
> into the shared code before pulling the plug.
Indeed - the patch I posted the other day doing proper scatterlist
merging in the common code is largely to that end.
> I also wonder if it is possible to do a step-by-step migration and
> support both old and new interfaces in the same binary? That may make
> things easier for multiplatform enablement. So far I've managed to
> make one IOMMU driver support both 32-bit ARM and 64-bit ARM with some
> ugly magic, so adjusting 32-bit ARM dma-mapping code to coexist with
> the shared code in drivers/iommu/dma-iommu.c may also be possible. And
> probably involving even more ugly magic. =)
That was also my thought when I tried to look at this a while ago - I
started on some patches moving the bitmap from dma_iommu_mapping into
the iommu_domain->iova_cookie so that the existing code and users could
then be converted to just passing iommu_domains around, after which it
should be fairly painless to swap out the back-end implementation
transparently. That particular effort ground to a halt upon realising
the number of the IOMMU and DRM drivers I'd have no way of testing - if
you're interested I've dug out the diff below from an old
work-in-progress branch (which probably doesn't even compile).
Robin.
>
> Cheers,
>
> / magnus
--->8---
diff --git a/arch/arm/include/asm/device.h b/arch/arm/include/asm/device.h
index 4111592..6ea939c 100644
--- a/arch/arm/include/asm/device.h
+++ b/arch/arm/include/asm/device.h
@@ -14,9 +14,6 @@ struct dev_archdata {
#ifdef CONFIG_IOMMU_API
void *iommu; /* private IOMMU data */
#endif
-#ifdef CONFIG_ARM_DMA_USE_IOMMU
- struct dma_iommu_mapping *mapping;
-#endif
bool dma_coherent;
};
@@ -28,10 +25,4 @@ struct pdev_archdata {
#endif
};
-#ifdef CONFIG_ARM_DMA_USE_IOMMU
-#define to_dma_iommu_mapping(dev) ((dev)->archdata.mapping)
-#else
-#define to_dma_iommu_mapping(dev) NULL
-#endif
-
#endif
diff --git a/arch/arm/include/asm/dma-iommu.h
b/arch/arm/include/asm/dma-iommu.h
index 2ef282f..e15197d 100644
--- a/arch/arm/include/asm/dma-iommu.h
+++ b/arch/arm/include/asm/dma-iommu.h
@@ -24,13 +24,12 @@ struct dma_iommu_mapping {
struct kref kref;
};
-struct dma_iommu_mapping *
+struct iommu_domain *
arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, u64 size);
-void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping);
+void arm_iommu_release_mapping(struct iommu_domain *mapping);
-int arm_iommu_attach_device(struct device *dev,
- struct dma_iommu_mapping *mapping);
+int arm_iommu_attach_device(struct device *dev, struct iommu_domain
*mapping);
void arm_iommu_detach_device(struct device *dev);
#endif /* __KERNEL__ */
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index e62400e..dfb5001 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1246,7 +1246,8 @@ __iommu_alloc_remap(struct page **pages, size_t
size, gfp_t gfp, pgprot_t prot,
static dma_addr_t
__iommu_create_mapping(struct device *dev, struct page **pages, size_t
size)
{
- struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ struct iommu_domain *dom = iommu_get_domain_for_dev(dev);
+ struct dma_iommu_mapping *mapping = dom->iova_cookie;
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
dma_addr_t dma_addr, iova;
int i;
@@ -1268,8 +1269,7 @@ __iommu_create_mapping(struct device *dev, struct
page **pages, size_t size)
break;
len = (j - i) << PAGE_SHIFT;
- ret = iommu_map(mapping->domain, iova, phys, len,
- IOMMU_READ|IOMMU_WRITE);
+ ret = iommu_map(dom, iova, phys, len, IOMMU_READ|IOMMU_WRITE);
if (ret < 0)
goto fail;
iova += len;
@@ -1277,14 +1277,14 @@ __iommu_create_mapping(struct device *dev,
struct page **pages, size_t size)
}
return dma_addr;
fail:
- iommu_unmap(mapping->domain, dma_addr, iova-dma_addr);
+ iommu_unmap(dom, dma_addr, iova-dma_addr);
__free_iova(mapping, dma_addr, size);
return DMA_ERROR_CODE;
}
static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova,
size_t size)
{
- struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ struct iommu_domain *dom = iommu_get_domain_for_dev(dev);
/*
* add optional in-page offset from iova to size and align
@@ -1293,8 +1293,8 @@ static int __iommu_remove_mapping(struct device
*dev, dma_addr_t iova, size_t si
size = PAGE_ALIGN((iova & ~PAGE_MASK) + size);
iova &= PAGE_MASK;
- iommu_unmap(mapping->domain, iova, size);
- __free_iova(mapping, iova, size);
+ iommu_unmap(dom, iova, size);
+ __free_iova(dom->iova_cookie, iova, size);
return 0;
}
@@ -1506,7 +1506,8 @@ static int __map_sg_chunk(struct device *dev,
struct scatterlist *sg,
enum dma_data_direction dir, struct dma_attrs *attrs,
bool is_coherent)
{
- struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ struct iommu_domain *dom = iommu_get_domain_for_dev(dev);
+ struct dma_iommu_mapping *mapping = dom->iova_cookie;
dma_addr_t iova, iova_base;
int ret = 0;
unsigned int count;
@@ -1530,7 +1531,7 @@ static int __map_sg_chunk(struct device *dev,
struct scatterlist *sg,
prot = __dma_direction_to_prot(dir);
- ret = iommu_map(mapping->domain, iova, phys, len, prot);
+ ret = iommu_map(dom, iova, phys, len, prot);
if (ret < 0)
goto fail;
count += len >> PAGE_SHIFT;
@@ -1540,7 +1541,7 @@ static int __map_sg_chunk(struct device *dev,
struct scatterlist *sg,
return 0;
fail:
- iommu_unmap(mapping->domain, iova_base, count * PAGE_SIZE);
+ iommu_unmap(dom, iova_base, count * PAGE_SIZE);
__free_iova(mapping, iova_base, size);
return ret;
}
@@ -1727,7 +1728,8 @@ static dma_addr_t
arm_coherent_iommu_map_page(struct device *dev, struct page *p
unsigned long offset, size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs)
{
- struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ struct iommu_domain *dom = iommu_get_domain_for_dev(dev);
+ struct dma_iommu_mapping *mapping = dom->iova_cookie;
dma_addr_t dma_addr;
int ret, prot, len = PAGE_ALIGN(size + offset);
@@ -1737,7 +1739,7 @@ static dma_addr_t
arm_coherent_iommu_map_page(struct device *dev, struct page *p
prot = __dma_direction_to_prot(dir);
- ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, prot);
+ ret = iommu_map(dom, dma_addr, page_to_phys(page), len, prot);
if (ret < 0)
goto fail;
@@ -1780,7 +1782,7 @@ static void arm_coherent_iommu_unmap_page(struct
device *dev, dma_addr_t handle,
size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs)
{
- struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ struct iommu_domain *dom = iommu_get_domain_for_dev(dev);
dma_addr_t iova = handle & PAGE_MASK;
int offset = handle & ~PAGE_MASK;
int len = PAGE_ALIGN(size + offset);
@@ -1788,8 +1790,8 @@ static void arm_coherent_iommu_unmap_page(struct
device *dev, dma_addr_t handle,
if (!iova)
return;
- iommu_unmap(mapping->domain, iova, len);
- __free_iova(mapping, iova, len);
+ iommu_unmap(dom, iova, len);
+ __free_iova(dom->iova_cookie, iova, len);
}
/**
@@ -1805,9 +1807,9 @@ static void arm_iommu_unmap_page(struct device
*dev, dma_addr_t handle,
size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs)
{
- struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ struct iommu_domain *dom = iommu_get_domain_for_dev(dev);
dma_addr_t iova = handle & PAGE_MASK;
- struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain,
iova));
+ struct page *page = phys_to_page(iommu_iova_to_phys(dom, iova));
int offset = handle & ~PAGE_MASK;
int len = PAGE_ALIGN(size + offset);
@@ -1817,16 +1819,16 @@ static void arm_iommu_unmap_page(struct device
*dev, dma_addr_t handle,
if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
__dma_page_dev_to_cpu(page, offset, size, dir);
- iommu_unmap(mapping->domain, iova, len);
- __free_iova(mapping, iova, len);
+ iommu_unmap(dom, iova, len);
+ __free_iova(dom->iova_cookie, iova, len);
}
static void arm_iommu_sync_single_for_cpu(struct device *dev,
dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
- struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ struct iommu_domain *dom = iommu_get_domain_for_dev(dev);
dma_addr_t iova = handle & PAGE_MASK;
- struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain,
iova));
+ struct page *page = phys_to_page(iommu_iova_to_phys(dom, iova));
unsigned int offset = handle & ~PAGE_MASK;
if (!iova)
@@ -1838,9 +1840,9 @@ static void arm_iommu_sync_single_for_cpu(struct
device *dev,
static void arm_iommu_sync_single_for_device(struct device *dev,
dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
- struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ struct iommu_domain *dom = iommu_get_domain_for_dev(dev);
dma_addr_t iova = handle & PAGE_MASK;
- struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain,
iova));
+ struct page *page = phys_to_page(iommu_iova_to_phys(dom, iova));
unsigned int offset = handle & ~PAGE_MASK;
if (!iova)
@@ -1896,12 +1898,13 @@ struct dma_map_ops iommu_coherent_ops = {
* The client device need to be attached to the mapping with
* arm_iommu_attach_device function.
*/
-struct dma_iommu_mapping *
+struct iommu_domain *
arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, u64 size)
{
unsigned int bits = size >> PAGE_SHIFT;
unsigned int bitmap_size = BITS_TO_LONGS(bits) * sizeof(long);
struct dma_iommu_mapping *mapping;
+ struct iommu_domain *dom;
int extensions = 1;
int err = -ENOMEM;
@@ -1938,12 +1941,14 @@ arm_iommu_create_mapping(struct bus_type *bus,
dma_addr_t base, u64 size)
spin_lock_init(&mapping->lock);
- mapping->domain = iommu_domain_alloc(bus);
- if (!mapping->domain)
+ dom = iommu_domain_alloc(bus);
+ if (!dom)
goto err4;
+ mapping->domain = dom;
+ dom->iova_cookie = mapping;
kref_init(&mapping->kref);
- return mapping;
+ return dom;
err4:
kfree(mapping->bitmaps[0]);
err3:
@@ -1986,24 +1991,27 @@ static int extend_iommu_mapping(struct
dma_iommu_mapping *mapping)
return 0;
}
-void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping)
+void arm_iommu_release_mapping(struct iommu_domain *domain)
{
- if (mapping)
+ if (domain) {
+ struct dma_iommu_mapping *mapping = domain->iova_cookie;
+
kref_put(&mapping->kref, release_iommu_mapping);
+ }
}
EXPORT_SYMBOL_GPL(arm_iommu_release_mapping);
static int __arm_iommu_attach_device(struct device *dev,
- struct dma_iommu_mapping *mapping)
+ struct iommu_domain *domain)
{
int err;
+ struct dma_iommu_mapping *mapping = domain->iova_cookie;
- err = iommu_attach_device(mapping->domain, dev);
+ err = iommu_attach_device(domain, dev);
if (err)
return err;
kref_get(&mapping->kref);
- to_dma_iommu_mapping(dev) = mapping;
pr_debug("Attached IOMMU controller to %s device.\n", dev_name(dev));
return 0;
@@ -2023,7 +2031,7 @@ static int __arm_iommu_attach_device(struct device
*dev,
* mapping.
*/
int arm_iommu_attach_device(struct device *dev,
- struct dma_iommu_mapping *mapping)
+ struct iommu_domain *mapping)
{
int err;
@@ -2039,16 +2047,17 @@ EXPORT_SYMBOL_GPL(arm_iommu_attach_device);
static void __arm_iommu_detach_device(struct device *dev)
{
struct dma_iommu_mapping *mapping;
+ struct iommu_domain *dom;
- mapping = to_dma_iommu_mapping(dev);
- if (!mapping) {
+ dom = iommu_get_domain_for_dev(dev);
+ if (!dom) {
dev_warn(dev, "Not attached\n");
return;
}
- iommu_detach_device(mapping->domain, dev);
+ mapping = dom->iova_cookie;
+ iommu_detach_device(dom, dev);
kref_put(&mapping->kref, release_iommu_mapping);
- to_dma_iommu_mapping(dev) = NULL;
pr_debug("Detached IOMMU controller from %s device.\n", dev_name(dev));
}
@@ -2075,7 +2084,7 @@ static struct dma_map_ops
*arm_get_iommu_dma_map_ops(bool coherent)
static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base,
u64 size,
struct iommu_ops *iommu)
{
- struct dma_iommu_mapping *mapping;
+ struct iommu_domain *mapping;
if (!iommu)
return false;
@@ -2099,13 +2108,13 @@ static bool arm_setup_iommu_dma_ops(struct
device *dev, u64 dma_base, u64 size,
static void arm_teardown_iommu_dma_ops(struct device *dev)
{
- struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ struct iommu_domain *mapping = iommu_get_domain_for_dev(dev);
if (!mapping)
return;
__arm_iommu_detach_device(dev);
- arm_iommu_release_mapping(mapping);
+ arm_iommu_release_mapping(mapping->iova_cookie);
}
#else
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