[U-Boot] [PATCH v3 5/7] arm/mach-bcm283x/mbox: Flush and invalidate dcache when using fw mailbox

Alexander Stein
2015-07-22T18:23:36Z

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>
---
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