DMA Atomic pool for arm64

For architectures without coherent DMA, memory for DMA may need to be remapped with coherent attributes. Factor out the the remapping code from arm and put it in a common location to reduce code duplication.

As part of this, the arm APIs are now migrated away from ioremap_page_range to the common APIs which use map_vm_area for remapping. This should be an equivalent change and using map_vm_area is more correct as ioremap_page_range is intended to bring in io addresses into the cpu space and not regular kernel managed memory.

Reviewed-by Catalin Marinas <[email protected]>

Signed-off-by Laura Abbott <[email protected]>

---
 arch/arm/mm/dma-mapping.c                | 57 +++++---------------------
 drivers/base/dma-mapping.c               | 68 ++++++++++++++++++++++++++++++++
 include/asm-generic/dma-mapping-common.h |  9 +++++
 3 files changed, 86 insertions(+), 48 deletions(-)

arch/arm/mm/dma-mapping.c +9 -48

index 4c88935..f5190ac 100644
@@ -297,37 +297,19 @@ static void *
 __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
        const void *caller)
 {
-       struct vm_struct *area;
-       unsigned long addr;
-
        /*
         * DMA allocation can be mapped to user space, so lets
         * set VM_USERMAP flags too.
         */
-       area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP,
-                                 caller);
-       if (!area)
-               return NULL;
-       addr = (unsigned long)area->addr;
-       area->phys_addr = __pfn_to_phys(page_to_pfn(page));
-
-       if (ioremap_page_range(addr, addr + size, area->phys_addr, prot)) {
-               vunmap((void *)addr);
-               return NULL;
-       }
-       return (void *)addr;
+       return dma_common_contiguous_remap(page, size,
+                       VM_ARM_DMA_CONSISTENT | VM_USERMAP,
+                       prot, caller);
 }
 
 static void __dma_free_remap(void *cpu_addr, size_t size)
 {
-       unsigned int flags = VM_ARM_DMA_CONSISTENT | VM_USERMAP;
-       struct vm_struct *area = find_vm_area(cpu_addr);
-       if (!area || (area->flags & flags) != flags) {
-               WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
-               return;
-       }
-       unmap_kernel_range((unsigned long)cpu_addr, size);
-       vunmap(cpu_addr);
+       dma_common_free_remap(cpu_addr, size,
+                       VM_ARM_DMA_CONSISTENT | VM_USERMAP);
 }
 
 #define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K

@@ -1261,29 +1243,8 @@ static void *
 __iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot,
                    const void *caller)
 {
-       unsigned int i, nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-       struct vm_struct *area;
-       unsigned long p;
-
-       area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP,
-                                 caller);
-       if (!area)
-               return NULL;
-
-       area->pages = pages;
-       area->nr_pages = nr_pages;
-       p = (unsigned long)area->addr;
-
-       for (i = 0; i < nr_pages; i++) {
-               phys_addr_t phys = __pfn_to_phys(page_to_pfn(pages[i]));
-               if (ioremap_page_range(p, p + PAGE_SIZE, phys, prot))
-                       goto err;
-               p += PAGE_SIZE;
-       }
-       return area->addr;
-err:
-       unmap_kernel_range((unsigned long)area->addr, size);
-       vunmap(area->addr);
+       return dma_common_pages_remap(pages, size,
+                       VM_ARM_DMA_CONSISTENT | VM_USERMAP, prot, caller);
        return NULL;
 }
 

@@ -1491,8 +1452,8 @@ void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
        }
 
        if (!dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) {
-               unmap_kernel_range((unsigned long)cpu_addr, size);
-               vunmap(cpu_addr);
+               dma_common_free_remap(cpu_addr, size,
+                       VM_ARM_DMA_CONSISTENT | VM_USERMAP);
        }
 
        __iommu_remove_mapping(dev, handle, size);

drivers/base/dma-mapping.c +68 -0

index 6cd08e1..1bc46df 100644
@@ -10,6 +10,8 @@
 #include <linux/dma-mapping.h>
 #include <linux/export.h>
 #include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
 #include <asm-generic/dma-coherent.h>
 
 /*

@@ -267,3 +269,69 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
        return ret;
 }
 EXPORT_SYMBOL(dma_common_mmap);
+
+/*
+ * remaps an allocated contiguous region into another vm_area.
+ * Cannot be used in non-sleeping contexts
+ */
+
+void *dma_common_contiguous_remap(struct page *page, size_t size,
+                       unsigned long vm_flags,
+                       pgprot_t prot, const void *caller)
+{
+       int i;
+       struct page **pages;
+       void *ptr;
+       unsigned long pfn;
+
+       pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
+       if (!pages)
+               return NULL;
+
+       for (i = 0, pfn = page_to_pfn(page); i < (size >> PAGE_SHIFT); i++)
+               pages[i] = pfn_to_page(pfn + i);
+
+       ptr = dma_common_pages_remap(pages, size, vm_flags, prot, caller);
+
+       kfree(pages);
+
+       return ptr;
+}
+
+/*
+ * remaps an array of PAGE_SIZE pages into another vm_area
+ * Cannot be used in non-sleeping contexts
+ */
+void *dma_common_pages_remap(struct page **pages, size_t size,
+                       unsigned long vm_flags, pgprot_t prot,
+                       const void *caller)
+{
+       struct vm_struct *area;
+
+       area = get_vm_area_caller(size, vm_flags, caller);
+       if (!area)
+               return NULL;
+
+       if (map_vm_area(area, prot, pages)) {
+               vunmap(area->addr);
+               return NULL;
+       }
+
+       return area->addr;
+}
+
+/*
+ * unmaps a range previously mapped by dma_common_*_remap
+ */
+void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
+{
+       struct vm_struct *area = find_vm_area(cpu_addr);
+
+       if (!area || (area->flags & vm_flags) != vm_flags) {
+               WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
+               return;
+       }
+
+       unmap_kernel_range((unsigned long)cpu_addr, size);
+       vunmap(cpu_addr);
+}

include/asm-generic/dma-mapping-common.h +9 -1

index de8bf89..a9fd248 100644
@@ -179,6 +179,15 @@ dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
                           void *cpu_addr, dma_addr_t dma_addr, size_t size);
 
+void *dma_common_contiguous_remap(struct page *page, size_t size,
+                       unsigned long vm_flags,
+                       pgprot_t prot, const void *caller);
+
+void *dma_common_pages_remap(struct page **pages, size_t size,
+                       unsigned long vm_flags, pgprot_t prot,
+                       const void *caller);
+void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags);
+
 /**
  * dma_mmap_attrs - map a coherent DMA allocation into user space
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
--

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Quoted 6 lines · Laura Abbott

For architectures without coherent DMA, memory for DMA may need to be remapped with coherent attributes. Factor out the the remapping code from arm and put it in a common location to reduce code duplication.

Quoted 8 lines

As part of this, the arm APIs are now migrated away from ioremap_page_range to the common APIs which use map_vm_area for remapping. This should be an equivalent change and using map_vm_area is more correct as ioremap_page_range is intended to bring in io addresses into the cpu space and not regular kernel managed memory.

Reviewed-by Catalin Marinas <[email protected]>

Signed-off-by Laura Abbott <[email protected]>

This commit in linux-next () breaks the build for metag:

drivers/base/dma-mapping.c: In function ?dma_common_contiguous_remap?:
drivers/base/dma-mapping.c:294: error: implicit declaration of function ?dma_common_pages_remap? drivers/base/dma-mapping.c:294: warning: assignment makes pointer from integer without a cast
drivers/base/dma-mapping.c: At top level:
drivers/base/dma-mapping.c:308: error: conflicting types for ?dma_common_pages_remap?
drivers/base/dma-mapping.c:294: error: previous implicit declaration of ?dma_common_pages_remap? was here

Looks like metag isn't alone either:

$ git grep -L dma-mapping-common arch/*/include/asm/dma-mapping.h
arch/arc/include/asm/dma-mapping.h
arch/avr32/include/asm/dma-mapping.h
arch/blackfin/include/asm/dma-mapping.h
arch/c6x/include/asm/dma-mapping.h
arch/cris/include/asm/dma-mapping.h
arch/frv/include/asm/dma-mapping.h
arch/m68k/include/asm/dma-mapping.h
arch/metag/include/asm/dma-mapping.h
arch/mn10300/include/asm/dma-mapping.h
arch/parisc/include/asm/dma-mapping.h
arch/xtensa/include/asm/dma-mapping.h

I've checked a couple of these arches (blackfin, xtensa) which don't include dma-mapping-common.h and their builds seem to be broken too.

Cheers
James

From 81c9a5504cbc1d72ff1df084d48502b248cd79d0 Mon Sep 17 00:00:00 2001

Quoted 47 lines · James Hogan

Quoted 6 lines · Laura Abbott

For architectures without coherent DMA, memory for DMA may need to be remapped with coherent attributes. Factor out the the remapping code from arm and put it in a common location to reduce code duplication.

Quoted 8 lines

As part of this, the arm APIs are now migrated away from ioremap_page_range to the common APIs which use map_vm_area for remapping. This should be an equivalent change and using map_vm_area is more correct as ioremap_page_range is intended to bring in io addresses into the cpu space and not regular kernel managed memory.

Reviewed-by Catalin Marinas <[email protected]>

Signed-off-by Laura Abbott <[email protected]>

This commit in linux-next () breaks the build for metag:

drivers/base/dma-mapping.c: In function ?dma_common_contiguous_remap?:
drivers/base/dma-mapping.c:294: error: implicit declaration of function ?dma_common_pages_remap? drivers/base/dma-mapping.c:294: warning: assignment makes pointer from integer without a cast
drivers/base/dma-mapping.c: At top level:
drivers/base/dma-mapping.c:308: error: conflicting types for ?dma_common_pages_remap?
drivers/base/dma-mapping.c:294: error: previous implicit declaration of ?dma_common_pages_remap? was here

Looks like metag isn't alone either:

$ git grep -L dma-mapping-common arch/*/include/asm/dma-mapping.h
arch/arc/include/asm/dma-mapping.h
arch/avr32/include/asm/dma-mapping.h
arch/blackfin/include/asm/dma-mapping.h
arch/c6x/include/asm/dma-mapping.h
arch/cris/include/asm/dma-mapping.h
arch/frv/include/asm/dma-mapping.h
arch/m68k/include/asm/dma-mapping.h
arch/metag/include/asm/dma-mapping.h
arch/mn10300/include/asm/dma-mapping.h
arch/parisc/include/asm/dma-mapping.h
arch/xtensa/include/asm/dma-mapping.h

I've checked a couple of these arches (blackfin, xtensa) which don't include dma-mapping-common.h and their builds seem to be broken too.

Quoted 3 lines

Cheers
James

Thanks for the report. Would you mind giving the following patch a test (this is theoretical only but I think it should work)

-----8<------

From 81c9a5504cbc1d72ff1df084d48502b248cd79d0 Mon Sep 17 00:00:00 2001
From: Laura Abbott <[email protected]>
Date: Tue, 26 Aug 2014 09:50:49 -0700
Subject: [PATCH] common: dma-mapping: Swap function order

Fix the order of dma_common_contiguous_remap and dma_common_pages_remap to avoid function declaration errors:

drivers/base/dma-mapping.c: In function 'dma_common_contiguous_remap':
drivers/base/dma-mapping.c:294: error: implicit declaration of function 'dma_common_pages_remap' drivers/base/dma-mapping.c:294: warning: assignment makes pointer from integer without a cast
drivers/base/dma-mapping.c: At top level:
drivers/base/dma-mapping.c:308: error: conflicting types for 'dma_common_pages_remap'
drivers/base/dma-mapping.c:294: error: previous implicit declaration of 'dma_common_pages_remap' was here

Change-Id I65db739114e8f5816a24a279a2ff1a6dc92e2b83

Reported-by James Hogan <[email protected]>

Reported-by kbuild test robot <[email protected]>

Signed-off-by Laura Abbott <[email protected]>

---
 drivers/base/dma-mapping.c | 44 ++++++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

drivers/base/dma-mapping.c +22 -22

index 1bc46df..056fd46 100644
@@ -271,6 +271,28 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 EXPORT_SYMBOL(dma_common_mmap);
 
 /*
+ * remaps an array of PAGE_SIZE pages into another vm_area
+ * Cannot be used in non-sleeping contexts
+ */
+void *dma_common_pages_remap(struct page **pages, size_t size,
+			unsigned long vm_flags, pgprot_t prot,
+			const void *caller)
+{
+	struct vm_struct *area;
+
+	area = get_vm_area_caller(size, vm_flags, caller);
+	if (!area)
+		return NULL;
+
+	if (map_vm_area(area, prot, pages)) {
+		vunmap(area->addr);
+		return NULL;
+	}
+
+	return area->addr;
+}
+
+/*
  * remaps an allocated contiguous region into another vm_area.
  * Cannot be used in non-sleeping contexts
  */

@@ -299,28 +321,6 @@ void *dma_common_contiguous_remap(struct page *page, size_t size,
 }
 
 /*
- * remaps an array of PAGE_SIZE pages into another vm_area
- * Cannot be used in non-sleeping contexts
- */
-void *dma_common_pages_remap(struct page **pages, size_t size,
-			unsigned long vm_flags, pgprot_t prot,
-			const void *caller)
-{
-	struct vm_struct *area;
-
-	area = get_vm_area_caller(size, vm_flags, caller);
-	if (!area)
-		return NULL;
-
-	if (map_vm_area(area, prot, pages)) {
-		vunmap(area->addr);
-		return NULL;
-	}
-
-	return area->addr;
-}
-
-/*
  * unmaps a range previously mapped by dma_common_*_remap
  */
 void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)

Quoted 47 lines · James Hogan

Quoted 6 lines · Laura Abbott

For architectures without coherent DMA, memory for DMA may need to be remapped with coherent attributes. Factor out the the remapping code from arm and put it in a common location to reduce code duplication.

Quoted 8 lines

As part of this, the arm APIs are now migrated away from ioremap_page_range to the common APIs which use map_vm_area for remapping. This should be an equivalent change and using map_vm_area is more correct as ioremap_page_range is intended to bring in io addresses into the cpu space and not regular kernel managed memory.

Reviewed-by Catalin Marinas <[email protected]>

Signed-off-by Laura Abbott <[email protected]>

This commit in linux-next () breaks the build for metag:

drivers/base/dma-mapping.c: In function ?dma_common_contiguous_remap?:
drivers/base/dma-mapping.c:294: error: implicit declaration of function ?dma_common_pages_remap? drivers/base/dma-mapping.c:294: warning: assignment makes pointer from integer without a cast
drivers/base/dma-mapping.c: At top level:
drivers/base/dma-mapping.c:308: error: conflicting types for ?dma_common_pages_remap?
drivers/base/dma-mapping.c:294: error: previous implicit declaration of ?dma_common_pages_remap? was here

Looks like metag isn't alone either:

$ git grep -L dma-mapping-common arch/*/include/asm/dma-mapping.h
arch/arc/include/asm/dma-mapping.h
arch/avr32/include/asm/dma-mapping.h
arch/blackfin/include/asm/dma-mapping.h
arch/c6x/include/asm/dma-mapping.h
arch/cris/include/asm/dma-mapping.h
arch/frv/include/asm/dma-mapping.h
arch/m68k/include/asm/dma-mapping.h
arch/metag/include/asm/dma-mapping.h
arch/mn10300/include/asm/dma-mapping.h
arch/parisc/include/asm/dma-mapping.h
arch/xtensa/include/asm/dma-mapping.h

I've checked a couple of these arches (blackfin, xtensa) which don't include dma-mapping-common.h and their builds seem to be broken too.

Quoted 3 lines

Cheers
James

Thanks for the report. Would you mind giving the following patch a test (this is theoretical only but I think it should work)