Commit 7d641938 authored May 13, 2015 by Eric Anholt Committed by Jassi Brar Jun 13, 2015

mailbox/bcm2835: Fix mailbox full detection.



With the VC reader blocked and the ARM writing, MAIL0_STA reads empty
permanently while MAIL1_STA goes from empty (0x40000000) to non-empty
(0x00000001-0x00000007) to full (0x80000008).

This bug ended up having no effect on us, because all of our
transactions in the client driver were synchronous and under a mutex.

Suggested-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

parent 07a7dba1

drivers/mailbox/bcm2835-mailbox.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -49,6 +49,7 @@
		#define MAIL0_STA (ARM_0_MAIL0 + 0x18)
		#define MAIL0_CNF (ARM_0_MAIL0 + 0x1C)
		#define MAIL1_WRT (ARM_0_MAIL1 + 0x00)
		#define MAIL1_STA (ARM_0_MAIL1 + 0x18)

		/* Status register: FIFO state. */
		#define ARM_MS_FULL BIT(31)
		@@ -117,7 +118,7 @@ static bool bcm2835_last_tx_done(struct mbox_chan *link)
		bool ret;

		spin_lock(&mbox->lock);
		ret = !(readl(mbox->regs + MAIL0_STA) & ARM_MS_FULL);
		ret = !(readl(mbox->regs + MAIL1_STA) & ARM_MS_FULL);
		spin_unlock(&mbox->lock);
		return ret;
		}