ENGR00217721-3 implement dma_alloc_noncacheable interface

arch/arm/mm part

- After USB driver prime a bulk transfer(whatever IN or OUT, take
  OUT for example) on ep1, only one dTD is primed, an USB Interrupt
  (bit 0 of USBSTS) will be issued, and find that endptcomplete
  register is 0x2 which means an OUT transfer on ep1 is completed,
  at this time the ep1 out queue head status is 0x1e18000, and next
  dtd pointer is 0x1 which means transfer is done and everything is
  OK, while the dTD token status is 0x2008080 which means this dTD
  is still active, not completed yet.
- Audio SDMA and Ethernet have the similar issue
- root cause is not found yet
- work around:
  change the non-cacheable bufferable memory to non-cacheable
  non-bufferable memory to make this issue disappear.

Signed-off-by: Tony LIU <junjie.liu@freescale.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 79e05f69631c..e134cfff3ba1 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -369,6 +369,22 @@ dma_alloc_writethrough(struct device *dev, size_t size, dma_addr_t *handle, gfp_
 }
 EXPORT_SYMBOL(dma_alloc_writethrough);
 
+
+#ifdef CONFIG_FSL_UTP
+/*
+ *  Allocate noncacheable memory space and return both the kernel remapped
+ * virtual and bus address for that space.
+ */
+void *
+dma_alloc_noncacheable(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
+{
+	return __dma_alloc(dev, size, handle, gfp,
+			  /*pgprot_writethrough(pgprot_kernel));*/
+			  pgprot_noncached(pgprot_kernel));
+}
+EXPORT_SYMBOL(dma_alloc_noncacheable);
+#endif
+
 static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
 		    void *cpu_addr, dma_addr_t dma_addr, size_t size)
 {