[ARM] 3209/1: Configurable DMA-consistent memory region
Patch from Kevin Hilman
This patch increase available DMA-consistent memory allocated by dma_coherent_alloc(). The default remains at 2M (defined in asm/memory.h) and each platform has the ability to override in asm/arch-foo/memory.h.
Signed-off-by: Kevin Hilman <kevin@hilman.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/consistent.c b/arch/arm/mm/consistent.c
index 0513ed1..c2ee18d 100644
--- a/arch/arm/mm/consistent.c
+++ b/arch/arm/mm/consistent.c
@@ -20,15 +20,25 @@
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
+#include <asm/sizes.h>
-#define CONSISTENT_BASE (0xffc00000)
+/* Sanity check size */
+#if (CONSISTENT_DMA_SIZE % SZ_2M)
+#error "CONSISTENT_DMA_SIZE must be multiple of 2MiB"
+#endif
+
#define CONSISTENT_END (0xffe00000)
+#define CONSISTENT_BASE (CONSISTENT_END - CONSISTENT_DMA_SIZE)
+
#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
+#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT)
+#define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT)
+
/*
- * This is the page table (2MB) covering uncached, DMA consistent allocations
+ * These are the page tables (2MB each) covering uncached, DMA consistent allocations
*/
-static pte_t *consistent_pte;
+static pte_t *consistent_pte[NUM_CONSISTENT_PTES];
static DEFINE_SPINLOCK(consistent_lock);
/*
@@ -142,7 +152,7 @@
unsigned long order;
u64 mask = ISA_DMA_THRESHOLD, limit;
- if (!consistent_pte) {
+ if (!consistent_pte[0]) {
printk(KERN_ERR "%s: not initialised\n", __func__);
dump_stack();
return NULL;
@@ -205,9 +215,12 @@
c = vm_region_alloc(&consistent_head, size,
gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
if (c) {
- pte_t *pte = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
+ pte_t *pte;
struct page *end = page + (1 << order);
+ 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;
/*
@@ -226,6 +239,11 @@
set_pte(pte, mk_pte(page, prot));
page++;
pte++;
+ off++;
+ if (off >= PTRS_PER_PTE) {
+ off = 0;
+ pte = consistent_pte[++idx];
+ }
} while (size -= PAGE_SIZE);
/*
@@ -327,6 +345,8 @@
struct vm_region *c;
unsigned long flags, addr;
pte_t *ptep;
+ int idx;
+ u32 off;
WARN_ON(irqs_disabled());
@@ -347,7 +367,9 @@
size = c->vm_end - c->vm_start;
}
- ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
+ 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);
@@ -355,6 +377,11 @@
ptep++;
addr += PAGE_SIZE;
+ off++;
+ if (off >= PTRS_PER_PTE) {
+ off = 0;
+ ptep = consistent_pte[++idx];
+ }
if (!pte_none(pte) && pte_present(pte)) {
pfn = pte_pfn(pte);
@@ -401,11 +428,12 @@
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
- int ret = 0;
+ int ret = 0, i = 0;
+ u32 base = CONSISTENT_BASE;
do {
- pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
- pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE);
+ pgd = pgd_offset(&init_mm, base);
+ pmd = pmd_alloc(&init_mm, pgd, base);
if (!pmd) {
printk(KERN_ERR "%s: no pmd tables\n", __func__);
ret = -ENOMEM;
@@ -413,15 +441,16 @@
}
WARN_ON(!pmd_none(*pmd));
- pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);
+ pte = pte_alloc_kernel(pmd, base);
if (!pte) {
printk(KERN_ERR "%s: no pte tables\n", __func__);
ret = -ENOMEM;
break;
}
- consistent_pte = pte;
- } while (0);
+ consistent_pte[i++] = pte;
+ base += (1 << PGDIR_SHIFT);
+ } while (base < CONSISTENT_END);
return ret;
}