On Friday 02 November 2012 06:02 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 by 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>
---
arch/arm/mach-omap2/mailbox.c | 42 ++++++++++++++++++++---------
arch/arm/plat-omap/include/plat/mailbox.h | 3 ++
arch/arm/plat-omap/mailbox.c | 35 ++++++++++++++++++++++++
3 files changed, 67 insertions(+), 13 deletions(-)
diff --git a/arch/arm/mach-omap2/mailbox.c b/arch/arm/mach-omap2/mailbox.c
index 0d97456..f38b4fa 100644
--- a/arch/arm/mach-omap2/mailbox.c
+++ b/arch/arm/mach-omap2/mailbox.c
@@ -123,6 +123,20 @@ static int omap2_mbox_fifo_full(struct omap_mbox *mbox)
return mbox_read_reg(fifo->fifo_stat);
}
+static int omap2_mbox_fifo_needs_flush(struct omap_mbox *mbox)
+{
+ struct omap_mbox2_fifo *fifo =
+ &((struct omap_mbox2_priv *)mbox->priv)->tx_fifo;
type casting is generally avoided in linux code.
+ return mbox_read_reg(fifo->msg_stat);
+}
+
+static mbox_msg_t omap2_mbox_fifo_readback(struct omap_mbox *mbox)
+{
+ struct omap_mbox2_fifo *fifo =
+ &((struct omap_mbox2_priv *)mbox->priv)->tx_fifo;
+ return (mbox_msg_t) mbox_read_reg(fifo->msg);
same here.
+}
+
/* Mailbox IRQ handle functions */
static void omap2_mbox_enable_irq(struct omap_mbox *mbox,
omap_mbox_type_t irq)
@@ -205,19 +219,21 @@ static void omap2_mbox_restore_ctx(struct omap_mbox *mbox)
}
static struct omap_mbox_ops omap2_mbox_ops = {
- .type = OMAP_MBOX_TYPE2,
- .startup = omap2_mbox_startup,
- .shutdown = omap2_mbox_shutdown,
- .fifo_read = omap2_mbox_fifo_read,
- .fifo_write = omap2_mbox_fifo_write,
- .fifo_empty = omap2_mbox_fifo_empty,
- .fifo_full = omap2_mbox_fifo_full,
- .enable_irq = omap2_mbox_enable_irq,
- .disable_irq = omap2_mbox_disable_irq,
- .ack_irq = omap2_mbox_ack_irq,
- .is_irq = omap2_mbox_is_irq,
- .save_ctx = omap2_mbox_save_ctx,
- .restore_ctx = omap2_mbox_restore_ctx,
+ .type = OMAP_MBOX_TYPE2,
+ .startup = omap2_mbox_startup,
+ .shutdown = omap2_mbox_shutdown,
+ .fifo_read = omap2_mbox_fifo_read,
+ .fifo_write = omap2_mbox_fifo_write,
+ .fifo_empty = omap2_mbox_fifo_empty,
+ .fifo_full = omap2_mbox_fifo_full,
+ .fifo_needs_flush = omap2_mbox_fifo_needs_flush,
+ .fifo_readback = omap2_mbox_fifo_readback,
+ .enable_irq = omap2_mbox_enable_irq,
+ .disable_irq = omap2_mbox_disable_irq,
+ .ack_irq = omap2_mbox_ack_irq,
+ .is_irq = omap2_mbox_is_irq,
+ .save_ctx = omap2_mbox_save_ctx,
+ .restore_ctx = omap2_mbox_restore_ctx,
You should do the indentation fix in another patch.
};
/*
diff --git a/arch/arm/plat-omap/include/plat/mailbox.h b/arch/arm/plat-omap/include/plat/mailbox.h
index cc3921e..e136529 100644
--- a/arch/arm/plat-omap/include/plat/mailbox.h
+++ b/arch/arm/plat-omap/include/plat/mailbox.h
@@ -29,6 +29,8 @@ struct omap_mbox_ops {
void (*fifo_write)(struct omap_mbox *mbox, mbox_msg_t msg);
int (*fifo_empty)(struct omap_mbox *mbox);
int (*fifo_full)(struct omap_mbox *mbox);
+ int (*fifo_needs_flush)(struct omap_mbox *mbox);
+ mbox_msg_t (*fifo_readback)(struct omap_mbox *mbox);
Do you think passing the msg structure as an argument and letting the
function populate it will be better instead of returning the msg
structure ? No strong opinion since from read_foo() point of view
what you have done might be right thing. In either case, please
get rid of typecasting.
Regards
Santosh
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