arm/mach-bcm283x/mbox: Flush and invalidate dcache when using fw mailbox

When using dcache the setup data for the mailbox must be actually written
into memory before calling into firmware. Thus flush and invalidate the
memory.

Signed-off-by: Alexander Stein <alexanders83@web.de>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>

arch/arm/mach-bcm283x/include/mach/mbox.h

@@ -522,6 +522,9 @@ int bcm2835_mbox_call_raw(u32 chan, u32 send, u32 *recv);
  * a termination value are expected to immediately follow the header in
  * memory, as required by the property protocol.
  *
+ * Each struct bcm2835_mbox_hdr passed must be allocated with
+ * ALLOC_CACHE_ALIGN_BUFFER(x, y, z) to ensure proper cache flush/invalidate.
+ *
  * Returns 0 for success, any other value for error.
  */
 int bcm2835_mbox_call_prop(u32 chan, struct bcm2835_mbox_hdr *buffer);

arch/arm/mach-bcm283x/mbox.c

@@ -111,9 +111,18 @@ int bcm2835_mbox_call_prop(u32 chan, struct bcm2835_mbox_hdr *buffer)
 	dump_buf(buffer);
 #endif
 
+	flush_dcache_range((unsigned long)buffer,
+			   (unsigned long)((void *)buffer +
+			   roundup(buffer->buf_size, ARCH_DMA_MINALIGN)));
+
 	ret = bcm2835_mbox_call_raw(chan, phys_to_bus((u32)buffer), &rbuffer);
 	if (ret)
 		return ret;
+
+	invalidate_dcache_range((unsigned long)buffer,
+				(unsigned long)((void *)buffer +
+				roundup(buffer->buf_size, ARCH_DMA_MINALIGN)));
+
 	if (rbuffer != phys_to_bus((u32)buffer)) {
 		printf("mbox: Response buffer mismatch\n");
 		return -1;