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Message-ID: <1242990702.22654.253.camel@zakaz.uk.xensource.com>
Date: Fri, 22 May 2009 12:11:42 +0100
From: Ian Campbell <Ian.Campbell@...citrix.com>
To: Becky Bruce <beckyb@...nel.crashing.org>
CC: Jeremy Fitzhardinge <jeremy@...p.org>,
FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>,
"linuxppc-dev@...abs.org" <linuxppc-dev@...abs.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2 2/3] powerpc: Add support for swiotlb on 32-bit
On Thu, 2009-05-21 at 14:27 -0400, Becky Bruce wrote:
> I can work with that, but it's going to be a bit inefficient, as I
> actually need the dma_addr_t, not the phys_addr_t, so I'll have to
> convert. In every case, this is a conversion I've already done and
> that I need in the calling code as well.
Does
dma_addr_t dma_map_range(struct device *hwdev, phys_addr_t addr,
size_t size);
work for you?
If the range does not need mapping then it returns the dma address, if
you needed to calculate the dma address anyway to figure out if mapping
is required then this is fine. If the range does need mapping then it
returns NULL.
This subsumes many of the phys->dma address conversions which would
otherwise be done in the callers. IMHO this is an architecture specific
detail which should be pushed down into the arch code as much as
possible. The only ones which I don't think can be pushed down are the
ones in swiotlb_virt_to_bus/swiotlb_bus_to_virt.
BTW do you need swiotlb_bus_to_virt to be __weak or is the fact that it
is implemented in terms of swiotlb_bus_to_phys sufficient?
I have an appointment all afternoon and it's a bank holiday on Monday
but here is my WIP patch as an example of what I'm thinking. Obviously
some cleanups are still very much required:
* The Xen specific stuff in arch/x86/include/asm/dma-mapping.h
clearly needs to be properly abstracted away (I just stuck it
there for testing).
* swiotlb_phys_to_bus and swiotlb_bus_to_phys need to move to
arch/*/include/asm/dma-mapping.h instead of being __weak
* Maybe swiotlb_bus_to_virt can become static again.
* Need to finish auditing the handful of non-swiotlb users of
is_buffer_dma_capable.
* It might be possible to implement swiolb_dma_mapping_error
and/or swiotlb_dma_supported in terms of dma_map_range.
* Minor detail: it doesn't actually work at the moment ;-)
Ian.
diff --git a/arch/ia64/include/asm/dma-mapping.h b/arch/ia64/include/asm/dma-mapping.h
index 36c0009..026667f 100644
--- a/arch/ia64/include/asm/dma-mapping.h
+++ b/arch/ia64/include/asm/dma-mapping.h
@@ -174,4 +174,12 @@ dma_cache_sync (struct device *dev, void *vaddr, size_t size,
#define dma_is_consistent(d, h) (1) /* all we do is coherent memory... */
+static inline dma_addr_t dma_map_range(struct device *dev, u64 mask,
+ phys_addr_t addr, size_t size)
+{
+ if (addr + size <= mask)
+ return addr;
+ return 0;
+}
+
#endif /* _ASM_IA64_DMA_MAPPING_H */
diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 916cbb6..b2813ab 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -309,4 +309,20 @@ static inline void dma_free_coherent(struct device *dev, size_t size,
ops->free_coherent(dev, size, vaddr, bus);
}
+static inline dma_addr_t dma_map_range(struct device *dev, u64 mask,
+ phys_addr_t addr, size_t size)
+{
+ dma_addr_t dma_addr;
+#ifdef CONFIG_XEN
+ extern int xen_range_needs_mapping(phys_addr_t paddr, size_t size);
+ if (xen_pv_domain() && xen_range_needs_mapping(addr, size))
+ return 0;
+#endif
+
+ dma_addr = swiotlb_phys_to_bus(dev, addr);
+ if (dma_addr + size <= mask)
+ return 0;
+ return dma_addr;
+}
+
#endif
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 2fffc22..c2b4196 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -145,8 +145,8 @@ again:
if (!page)
return NULL;
- addr = page_to_phys(page);
- if (!is_buffer_dma_capable(dma_mask, addr, size)) {
+ addr = dma_map_range(dev, dma_mask, page_to_phys(page), size);
+ if (!(addr == 0)) {
__free_pages(page, get_order(size));
if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index 1e8920d..6a55770 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -191,13 +191,13 @@ static inline int
need_iommu(struct device *dev, unsigned long addr, size_t size)
{
return force_iommu ||
- !is_buffer_dma_capable(*dev->dma_mask, addr, size);
+ dma_map_range(dev, *dev->dma_mask, addr, size) == 0;
}
static inline int
nonforced_iommu(struct device *dev, unsigned long addr, size_t size)
{
- return !is_buffer_dma_capable(*dev->dma_mask, addr, size);
+ return dma_map_range(dev, *dev->dma_mask, addr, size) == 0;
}
/* Map a single continuous physical area into the IOMMU.
diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
index 71d412a..712ce59 100644
--- a/arch/x86/kernel/pci-nommu.c
+++ b/arch/x86/kernel/pci-nommu.c
@@ -12,13 +12,13 @@
#include <asm/dma.h>
static int
-check_addr(char *name, struct device *hwdev, dma_addr_t bus, size_t size)
+check_addr(char *name, struct device *hwdev, phys_addr_t phys, size_t size)
{
- if (hwdev && !is_buffer_dma_capable(*hwdev->dma_mask, bus, size)) {
+ if (hwdev && dma_map_range(hwdev, *hwdev->dma_mask, phys, size) == 0) {
if (*hwdev->dma_mask >= DMA_BIT_MASK(32))
printk(KERN_ERR
"nommu_%s: overflow %Lx+%zu of device mask %Lx\n",
- name, (long long)bus, size,
+ name, (long long)phys, size,
(long long)*hwdev->dma_mask);
return 0;
}
@@ -30,12 +30,12 @@ static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
enum dma_data_direction dir,
struct dma_attrs *attrs)
{
- dma_addr_t bus = page_to_phys(page) + offset;
+ phys_addr_t phys = page_to_phys(page) + offset;
WARN_ON(size == 0);
- if (!check_addr("map_single", dev, bus, size))
+ if (!check_addr("map_single", dev, phys, size))
return bad_dma_address;
flush_write_buffers();
- return bus;
+ return phys;
}
/* Map a set of buffers described by scatterlist in streaming
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 8083b6a..85dafa1 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -96,11 +96,6 @@ static inline int is_device_dma_capable(struct device *dev)
return dev->dma_mask != NULL && *dev->dma_mask != DMA_MASK_NONE;
}
-static inline int is_buffer_dma_capable(u64 mask, dma_addr_t addr, size_t size)
-{
- return addr + size <= mask;
-}
-
#ifdef CONFIG_HAS_DMA
#include <asm/dma-mapping.h>
#else
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index cec5f62..4fd5185 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -147,17 +147,6 @@ void * __weak swiotlb_bus_to_virt(struct device *hwdev, dma_addr_t address)
return phys_to_virt(swiotlb_bus_to_phys(hwdev, address));
}
-int __weak swiotlb_arch_address_needs_mapping(struct device *hwdev,
- dma_addr_t addr, size_t size)
-{
- return !is_buffer_dma_capable(dma_get_mask(hwdev), addr, size);
-}
-
-int __weak swiotlb_arch_range_needs_mapping(phys_addr_t paddr, size_t size)
-{
- return 0;
-}
-
static void swiotlb_print_info(unsigned long bytes)
{
phys_addr_t pstart, pend;
@@ -318,17 +307,6 @@ cleanup1:
return -ENOMEM;
}
-static inline int
-address_needs_mapping(struct device *hwdev, dma_addr_t addr, size_t size)
-{
- return swiotlb_arch_address_needs_mapping(hwdev, addr, size);
-}
-
-static inline int range_needs_mapping(phys_addr_t paddr, size_t size)
-{
- return swiotlb_force || swiotlb_arch_range_needs_mapping(paddr, size);
-}
-
static int is_swiotlb_buffer(char *addr)
{
return addr >= io_tlb_start && addr < io_tlb_end;
@@ -555,18 +533,17 @@ void *
swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags)
{
- dma_addr_t dev_addr;
+ phys_addr_t phys;
void *ret;
int order = get_order(size);
u64 dma_mask = DMA_BIT_MASK(32);
+ dma_addr_t dma_addr;
if (hwdev && hwdev->coherent_dma_mask)
dma_mask = hwdev->coherent_dma_mask;
ret = (void *)__get_free_pages(flags, order);
- if (ret &&
- !is_buffer_dma_capable(dma_mask, swiotlb_virt_to_bus(hwdev, ret),
- size)) {
+ if (ret && dma_map_range(hwdev, dma_mask, virt_to_phys(ret), size) == 0) {
/*
* The allocated memory isn't reachable by the device.
*/
@@ -585,19 +562,20 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
}
memset(ret, 0, size);
- dev_addr = swiotlb_virt_to_bus(hwdev, ret);
+ phys = virt_to_phys(ret);
/* Confirm address can be DMA'd by device */
- if (!is_buffer_dma_capable(dma_mask, dev_addr, size)) {
- printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n",
+ dma_addr = dma_map_range(hwdev, dma_mask, phys, size);
+ if (dma_addr == 0) {
+ printk("hwdev DMA mask = 0x%016Lx, physical addr = 0x%016Lx\n",
(unsigned long long)dma_mask,
- (unsigned long long)dev_addr);
+ (unsigned long long)phys);
/* DMA_TO_DEVICE to avoid memcpy in unmap_single */
do_unmap_single(hwdev, ret, size, DMA_TO_DEVICE);
return NULL;
}
- *dma_handle = dev_addr;
+ *dma_handle = dma_addr;
return ret;
}
EXPORT_SYMBOL(swiotlb_alloc_coherent);
@@ -649,7 +627,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
struct dma_attrs *attrs)
{
phys_addr_t phys = page_to_phys(page) + offset;
- dma_addr_t dev_addr = swiotlb_phys_to_bus(dev, phys);
+ dma_addr_t dma_addr;
void *map;
BUG_ON(dir == DMA_NONE);
@@ -658,9 +636,9 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
* we can safely return the device addr and not worry about bounce
* buffering it.
*/
- if (!address_needs_mapping(dev, dev_addr, size) &&
- !range_needs_mapping(phys, size))
- return dev_addr;
+ dma_addr = dma_map_range(dev, dma_get_mask(dev), phys, size);
+ if (dma_addr && !swiotlb_force)
+ return dma_addr;
/*
* Oh well, have to allocate and map a bounce buffer.
@@ -671,15 +649,14 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
map = io_tlb_overflow_buffer;
}
- dev_addr = swiotlb_virt_to_bus(dev, map);
-
/*
* Ensure that the address returned is DMA'ble
*/
- if (address_needs_mapping(dev, dev_addr, size))
+ dma_addr = dma_map_range(dev, dma_get_mask(dev), virt_to_phys(map), size);
+ if (dma_addr == 0)
panic("map_single: bounce buffer is not DMA'ble");
- return dev_addr;
+ return dma_addr;
}
EXPORT_SYMBOL_GPL(swiotlb_map_page);
@@ -820,10 +797,8 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
for_each_sg(sgl, sg, nelems, i) {
phys_addr_t paddr = sg_phys(sg);
- dma_addr_t dev_addr = swiotlb_phys_to_bus(hwdev, paddr);
-
- if (range_needs_mapping(paddr, sg->length) ||
- address_needs_mapping(hwdev, dev_addr, sg->length)) {
+ dma_addr_t dma_addr = dma_map_range(hwdev, dma_get_mask(hwdev), paddr, sg->length);
+ if (dma_addr == 0 || swiotlb_force) {
void *map = map_single(hwdev, sg_phys(sg),
sg->length, dir);
if (!map) {
@@ -835,9 +810,9 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
sgl[0].dma_length = 0;
return 0;
}
- sg->dma_address = swiotlb_virt_to_bus(hwdev, map);
- } else
- sg->dma_address = dev_addr;
+ dma_addr = dma_map_range(hwdev, dma_get_mask(hwdev), virt_to_phys(map), sg->length);
+ }
+ sg->dma_address = dma_addr;
sg->dma_length = sg->length;
}
return nelems;
--
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