nommu: Add noMMU support to the DMA API
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 510c179..b30925f 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -36,7 +36,34 @@
#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT)
#define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT)
+static u64 get_coherent_dma_mask(struct device *dev)
+{
+ u64 mask = ISA_DMA_THRESHOLD;
+ if (dev) {
+ mask = dev->coherent_dma_mask;
+
+ /*
+ * Sanity check the DMA mask - it must be non-zero, and
+ * must be able to be satisfied by a DMA allocation.
+ */
+ if (mask == 0) {
+ dev_warn(dev, "coherent DMA mask is unset\n");
+ return 0;
+ }
+
+ if ((~mask) & ISA_DMA_THRESHOLD) {
+ dev_warn(dev, "coherent DMA mask %#llx is smaller "
+ "than system GFP_DMA mask %#llx\n",
+ mask, (unsigned long long)ISA_DMA_THRESHOLD);
+ return 0;
+ }
+ }
+
+ return mask;
+}
+
+#ifdef CONFIG_MMU
/*
* These are the page tables (2MB each) covering uncached, DMA consistent allocations
*/
@@ -152,7 +179,8 @@
struct page *page;
struct arm_vm_region *c;
unsigned long order;
- u64 mask = ISA_DMA_THRESHOLD, limit;
+ u64 mask = get_coherent_dma_mask(dev);
+ u64 limit;
if (!consistent_pte[0]) {
printk(KERN_ERR "%s: not initialised\n", __func__);
@@ -160,25 +188,8 @@
return NULL;
}
- if (dev) {
- mask = dev->coherent_dma_mask;
-
- /*
- * Sanity check the DMA mask - it must be non-zero, and
- * must be able to be satisfied by a DMA allocation.
- */
- if (mask == 0) {
- dev_warn(dev, "coherent DMA mask is unset\n");
- goto no_page;
- }
-
- if ((~mask) & ISA_DMA_THRESHOLD) {
- dev_warn(dev, "coherent DMA mask %#llx is smaller "
- "than system GFP_DMA mask %#llx\n",
- mask, (unsigned long long)ISA_DMA_THRESHOLD);
- goto no_page;
- }
- }
+ if (!mask)
+ goto no_page;
/*
* Sanity check the allocation size.
@@ -267,6 +278,31 @@
*handle = ~0;
return NULL;
}
+#else /* !CONFIG_MMU */
+static void *
+__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
+ pgprot_t prot)
+{
+ void *virt;
+ u64 mask = get_coherent_dma_mask(dev);
+
+ if (!mask)
+ goto error;
+
+ if (mask != 0xffffffff)
+ gfp |= GFP_DMA;
+ virt = kmalloc(size, gfp);
+ if (!virt)
+ goto error;
+
+ *handle = virt_to_dma(dev, virt);
+ return virt;
+
+error:
+ *handle = ~0;
+ return NULL;
+}
+#endif /* CONFIG_MMU */
/*
* Allocate DMA-coherent memory space and return both the kernel remapped
@@ -311,9 +347,10 @@
static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size)
{
+ int ret = -ENXIO;
+#ifdef CONFIG_MMU
unsigned long flags, user_size, kern_size;
struct arm_vm_region *c;
- int ret = -ENXIO;
user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
@@ -334,6 +371,7 @@
vma->vm_page_prot);
}
}
+#endif /* CONFIG_MMU */
return ret;
}
@@ -358,6 +396,7 @@
* free a page as defined by the above mapping.
* Must not be called with IRQs disabled.
*/
+#ifdef CONFIG_MMU
void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
{
struct arm_vm_region *c;
@@ -444,6 +483,14 @@
__func__, cpu_addr);
dump_stack();
}
+#else /* !CONFIG_MMU */
+void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
+{
+ if (dma_release_from_coherent(dev, get_order(size), cpu_addr))
+ return;
+ kfree(cpu_addr);
+}
+#endif /* CONFIG_MMU */
EXPORT_SYMBOL(dma_free_coherent);
/*
@@ -451,10 +498,12 @@
*/
static int __init consistent_init(void)
{
+ int ret = 0;
+#ifdef CONFIG_MMU
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
- int ret = 0, i = 0;
+ int i = 0;
u32 base = CONSISTENT_BASE;
do {
@@ -477,6 +526,7 @@
consistent_pte[i++] = pte;
base += (1 << PGDIR_SHIFT);
} while (base < CONSISTENT_END);
+#endif /* !CONFIG_MMU */
return ret;
}