[U-Boot] [PATCH v4 5/7] arm/mach-bcm283x/mbox: Flush and invalidate dcache when using fw mailbox

[Alexander Stein]

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 at web.de>
Acked-by: Stephen Warren <swarren at wwwdotorg.org>
Tested-by: Stephen Warren <swarren at wwwdotorg.org>
---
Changes in v3:
* Use ARCH_DMA_MINALIGN instead of fixed 32
* Adjust comment in header

Changes in v2:
* Add hint in header about alignment requirements
* Invalidate cache after calling into mailbox
* round size up to next cacheline size

 arch/arm/mach-bcm283x/include/mach/mbox.h | 3 +++
 arch/arm/mach-bcm283x/mbox.c              | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/arch/arm/mach-bcm283x/include/mach/mbox.h b/arch/arm/mach-bcm283x/include/mach/mbox.h
index 54d369c..ff959c8 100644
--- a/arch/arm/mach-bcm283x/include/mach/mbox.h
+++ b/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);
diff --git a/arch/arm/mach-bcm283x/mbox.c b/arch/arm/mach-bcm283x/mbox.c
index 1af9be7..311bd8f 100644
--- a/arch/arm/mach-bcm283x/mbox.c
+++ b/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;
-- 
2.4.6