[PATCH 4/4] ARM: remove consistent dma region and use common vmalloc range for dma allocations
Marek Szyprowski
m.szyprowski at samsung.com
Fri Apr 13 10:05:50 EDT 2012
This patch changes dma-mapping subsystem to use generic vmalloc areas
for all consistent dma allocations. This increases the total size limit
of the consistent allocations and removes platform hacks and a lot of
duplicated code.
Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
Reviewed-by: Kyungmin Park <kyungmin.park at samsung.com>
---
arch/arm/include/asm/dma-mapping.h | 2 +-
arch/arm/mm/dma-mapping.c | 220 +++++++-----------------------------
2 files changed, 40 insertions(+), 182 deletions(-)
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index cb3b7c9..92b0afb 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -210,7 +210,7 @@ int dma_mmap_writecombine(struct device *, struct vm_area_struct *,
* DMA region above it's default value of 2MB. It must be called before the
* memory allocator is initialised, i.e. before any core_initcall.
*/
-extern void __init init_consistent_dma_size(unsigned long size);
+static inline void init_consistent_dma_size(unsigned long size) { }
#ifdef CONFIG_DMABOUNCE
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index db23ae4..74ff839 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -19,6 +19,8 @@
#include <linux/dma-mapping.h>
#include <linux/highmem.h>
#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/io.h>
#include <asm/memory.h>
#include <asm/highmem.h>
@@ -119,204 +121,59 @@ static void __dma_free_buffer(struct page *page, size_t size)
}
#ifdef CONFIG_MMU
-
-#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - consistent_base) >> PAGE_SHIFT)
-#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - consistent_base) >> PMD_SHIFT)
-
-/*
- * These are the page tables (2MB each) covering uncached, DMA consistent allocations
- */
-static pte_t **consistent_pte;
-
-#define DEFAULT_CONSISTENT_DMA_SIZE SZ_2M
-
-unsigned long consistent_base = CONSISTENT_END - DEFAULT_CONSISTENT_DMA_SIZE;
-
-void __init init_consistent_dma_size(unsigned long size)
-{
- unsigned long base = CONSISTENT_END - ALIGN(size, SZ_2M);
-
- BUG_ON(consistent_pte); /* Check we're called before DMA region init */
- BUG_ON(base < VMALLOC_END);
-
- /* Grow region to accommodate specified size */
- if (base < consistent_base)
- consistent_base = base;
-}
-
-#include "vmregion.h"
-
-static struct arm_vmregion_head consistent_head = {
- .vm_lock = __SPIN_LOCK_UNLOCKED(&consistent_head.vm_lock),
- .vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
- .vm_end = CONSISTENT_END,
-};
-
#ifdef CONFIG_HUGETLB_PAGE
#error ARM Coherent DMA allocator does not (yet) support huge TLB
#endif
-/*
- * Initialise the consistent memory allocation.
- */
-static int __init consistent_init(void)
-{
- int ret = 0;
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
- int i = 0;
- unsigned long base = consistent_base;
- unsigned long num_ptes = (CONSISTENT_END - base) >> PMD_SHIFT;
-
- consistent_pte = kmalloc(num_ptes * sizeof(pte_t), GFP_KERNEL);
- if (!consistent_pte) {
- pr_err("%s: no memory\n", __func__);
- return -ENOMEM;
- }
-
- pr_debug("DMA memory: 0x%08lx - 0x%08lx:\n", base, CONSISTENT_END);
- consistent_head.vm_start = base;
-
- do {
- pgd = pgd_offset(&init_mm, base);
-
- pud = pud_alloc(&init_mm, pgd, base);
- if (!pud) {
- printk(KERN_ERR "%s: no pud tables\n", __func__);
- ret = -ENOMEM;
- break;
- }
-
- pmd = pmd_alloc(&init_mm, pud, base);
- if (!pmd) {
- printk(KERN_ERR "%s: no pmd tables\n", __func__);
- ret = -ENOMEM;
- break;
- }
- WARN_ON(!pmd_none(*pmd));
-
- pte = pte_alloc_kernel(pmd, base);
- if (!pte) {
- printk(KERN_ERR "%s: no pte tables\n", __func__);
- ret = -ENOMEM;
- break;
- }
-
- consistent_pte[i++] = pte;
- base += PMD_SIZE;
- } while (base < CONSISTENT_END);
-
- return ret;
-}
-
-core_initcall(consistent_init);
-
static void *
__dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
const void *caller)
{
- struct arm_vmregion *c;
- size_t align;
- int bit;
-
- if (!consistent_pte) {
- printk(KERN_ERR "%s: not initialised\n", __func__);
- dump_stack();
- return NULL;
- }
-
- /*
- * Align the virtual region allocation - maximum alignment is
- * a section size, minimum is a page size. This helps reduce
- * fragmentation of the DMA space, and also prevents allocations
- * smaller than a section from crossing a section boundary.
- */
- bit = fls(size - 1);
- if (bit > SECTION_SHIFT)
- bit = SECTION_SHIFT;
- align = 1 << bit;
-
- /*
- * Allocate a virtual address in the consistent mapping region.
- */
- c = arm_vmregion_alloc(&consistent_head, align, size,
- gfp & ~(__GFP_DMA | __GFP_HIGHMEM), caller);
- if (c) {
- pte_t *pte;
- int idx = CONSISTENT_PTE_INDEX(c->vm_start);
- u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
-
- pte = consistent_pte[idx] + off;
- c->vm_pages = page;
-
- do {
- BUG_ON(!pte_none(*pte));
-
- set_pte_ext(pte, mk_pte(page, prot), 0);
- page++;
- pte++;
- off++;
- if (off >= PTRS_PER_PTE) {
- off = 0;
- pte = consistent_pte[++idx];
- }
- } while (size -= PAGE_SIZE);
-
- dsb();
+ struct vm_struct *area;
+ unsigned long addr;
- return (void *)c->vm_start;
- }
- return NULL;
+ area = get_vm_area_caller(size, VM_DMA | 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;
}
static void __dma_free_remap(void *cpu_addr, size_t size)
{
- struct arm_vmregion *c;
- unsigned long addr;
- pte_t *ptep;
- int idx;
- u32 off;
+ struct vm_struct *area;
+
+ read_lock(&vmlist_lock);
- c = arm_vmregion_find_remove(&consistent_head, (unsigned long)cpu_addr);
- if (!c) {
+ area = find_vm_area(cpu_addr);
+ if (!area) {
printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
__func__, cpu_addr);
dump_stack();
+ read_unlock(&vmlist_lock);
return;
}
- if ((c->vm_end - c->vm_start) != size) {
+ /*
+ * get_vm_area_caller always use additional guard page, so skip it here
+ */
+ if (area->size - PAGE_SIZE != size) {
printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
- __func__, c->vm_end - c->vm_start, size);
+ __func__, area->size, size);
dump_stack();
- size = c->vm_end - c->vm_start;
+ size = area->size;
}
- idx = CONSISTENT_PTE_INDEX(c->vm_start);
- off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
- ptep = consistent_pte[idx] + off;
- addr = c->vm_start;
- do {
- pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
-
- ptep++;
- addr += PAGE_SIZE;
- off++;
- if (off >= PTRS_PER_PTE) {
- off = 0;
- ptep = consistent_pte[++idx];
- }
-
- if (pte_none(pte) || !pte_present(pte))
- printk(KERN_CRIT "%s: bad page in kernel page table\n",
- __func__);
- } while (size -= PAGE_SIZE);
+ unmap_kernel_range((unsigned long)cpu_addr, size);
+ read_unlock(&vmlist_lock);
- flush_tlb_kernel_range(c->vm_start, c->vm_end);
-
- arm_vmregion_free(&consistent_head, c);
+ vunmap(cpu_addr);
}
#else /* !CONFIG_MMU */
@@ -398,25 +255,29 @@ static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
{
int ret = -ENXIO;
#ifdef CONFIG_MMU
+ struct vm_struct *area;
unsigned long user_size, kern_size;
- struct arm_vmregion *c;
+ read_lock(&vmlist_lock);
+ area = find_vm_area(cpu_addr);
user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
- c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
- if (c) {
+ if (area) {
unsigned long off = vma->vm_pgoff;
+ unsigned long phys = __phys_to_pfn(area->phys_addr);
- kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
+ /* skip vmalloc guard page */
+ kern_size = (area->size >> PAGE_SHIFT) - 1;
if (off < kern_size &&
user_size <= (kern_size - off)) {
ret = remap_pfn_range(vma, vma->vm_start,
- page_to_pfn(c->vm_pages) + off,
+ phys + off,
user_size << PAGE_SHIFT,
vma->vm_page_prot);
}
}
+ read_unlock(&vmlist_lock);
#endif /* CONFIG_MMU */
return ret;
@@ -726,9 +587,6 @@ EXPORT_SYMBOL(dma_set_mask);
static int __init dma_debug_do_init(void)
{
-#ifdef CONFIG_MMU
- arm_vmregion_create_proc("dma-mappings", &consistent_head);
-#endif
dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
return 0;
}
--
1.7.1.569.g6f426
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