On Monday 31 December 2012 06:36 PM, Vaibhav Bedia wrote:
On AM33XX, the mailbox module between the MPU and the
WKUP-M3 co-processor facilitates a one-way communication.
MPU uses the assigned mailbox sub-module to issue the
interrupt to the WKUP-M3 co-processor which then goes
and reads the the IPC data from registers in the control
module.
WKUP-M3 is in the L4_WKUP and does not have any access to
the mailbox module. Due to this limitation, the MPU is
completely responsible for FIFO maintenance and interrupt
generation. MPU needs to ensure that the FIFO does not
overflow by reading back the assigned mailbox sub-module.
This patch adds an API in the mailbox code which the MPU
can use to empty the FIFO by issuing a readback command.
Signed-off-by: Vaibhav Bedia <vaibhav.bedia@xxxxxx>
Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
---
Note: This patch which will be slightly reworked once the mailbox
driver changes are finalized.
Can you expand a bit please ?
drivers/mailbox/mailbox-omap2.c | 19 +++++++++++++++++++
drivers/mailbox/mailbox.c | 36 ++++++++++++++++++++++++++++++++++++
drivers/mailbox/mailbox.h | 3 +++
include/linux/mailbox.h | 1 +
4 files changed, 59 insertions(+), 0 deletions(-)
diff --git a/drivers/mailbox/mailbox-omap2.c b/drivers/mailbox/mailbox-omap2.c
index 6d61159..c732be1 100644
--- a/drivers/mailbox/mailbox-omap2.c
+++ b/drivers/mailbox/mailbox-omap2.c
@@ -125,6 +125,23 @@ static int omap2_mbox_fifo_full(struct mailbox *mbox)
return mbox_read_reg(fifo->fifo_stat);
}
+static int omap2_mbox_fifo_needs_flush(struct mailbox *mbox)
+{
+ struct omap_mbox2_priv *p = mbox->priv;
+ struct omap_mbox2_fifo *fifo = &p->tx_fifo;
+
+ return mbox_read_reg(fifo->msg_stat);
+}
+
+static void omap2_mbox_fifo_readback(struct mailbox *mbox,
+ struct mailbox_msg *msg)
+{
+ struct omap_mbox2_priv *p = mbox->priv;
+ struct omap_mbox2_fifo *fifo = &p->tx_fifo;
+
+ msg->header = mbox_read_reg(fifo->msg);
+}
+
static int ompa2_mbox_poll_for_space(struct mailbox *mbox)
{
if (omap2_mbox_fifo_full(mbox))
@@ -221,6 +238,8 @@ static struct mailbox_ops omap2_mbox_ops = {
.read = omap2_mbox_fifo_read,
.write = omap2_mbox_fifo_write,
.empty = omap2_mbox_fifo_empty,
+ .fifo_needs_flush = omap2_mbox_fifo_needs_flush,
+ .fifo_readback = omap2_mbox_fifo_readback,
.poll_for_space = ompa2_mbox_poll_for_space,
.enable_irq = omap2_mbox_enable_irq,
.disable_irq = omap2_mbox_disable_irq,
diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 2f50226..92c9f68 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -57,6 +57,15 @@ static inline int mbox_empty(struct mailbox *mbox)
{
return mbox->ops->empty(mbox);
}
+static inline int mbox_fifo_needs_flush(struct mailbox *mbox)
+{
+ return mbox->ops->fifo_needs_flush(mbox);
+}
+static inline void mbox_fifo_readback(struct mailbox *mbox,
+ struct mailbox_msg *msg)
+{
+ mbox->ops->fifo_readback(mbox, msg);
+}
/* Mailbox IRQ handle functions */
static inline void ack_mbox_irq(struct mailbox *mbox, mailbox_irq_t irq)
@@ -110,6 +119,33 @@ out:
}
EXPORT_SYMBOL(mailbox_msg_send);
+/*
s/*/**
+ * Flush the Rx FIFO by reading back the messages
+ * Since the normal expectation is that the Rx will do the
+ * reading, add a debug message to indicate if we really flush
+ *
+ * Returns the no. of messages read back
+ */
Just look at the kernel doc style for above
Rest looks fine.
Regards
Santosh
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
