On 22/07/14 19:56, Jassi Brar wrote:
Introduce common framework for client/protocol drivers and
controller drivers of Inter-Processor-Communication (IPC).
Client driver developers should have a look at
include/linux/mailbox_client.h to understand the part of
the API exposed to client drivers.
Similarly controller driver developers should have a look
at include/linux/mailbox_controller.h
Signed-off-by: Jassi Brar <jaswinder.singh@xxxxxxxxxx>
---
MAINTAINERS | 8 +
drivers/mailbox/Makefile | 4 +
drivers/mailbox/mailbox.c | 467 +++++++++++++++++++++++++++++++++++++
include/linux/mailbox_client.h | 45 ++++
include/linux/mailbox_controller.h | 131 +++++++++++
5 files changed, 655 insertions(+)
create mode 100644 drivers/mailbox/mailbox.c
create mode 100644 include/linux/mailbox_client.h
create mode 100644 include/linux/mailbox_controller.h
[...]
diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
new file mode 100644
index 0000000..99c0d23
--- /dev/null
+++ b/drivers/mailbox/mailbox.c
@@ -0,0 +1,467 @@
+/*
+ * Mailbox: Common code for Mailbox controllers and users
+ *
+ * Copyright (C) 2013-2014 Linaro Ltd.
+ * Author: Jassi Brar <jassisinghbrar@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/mailbox_client.h>
+#include <linux/mailbox_controller.h>
+
+#define TXDONE_BY_IRQ (1 << 0) /* controller has remote RTR irq */
+#define TXDONE_BY_POLL (1 << 1) /* controller can read status of last TX */
+#define TXDONE_BY_ACK (1 << 2) /* S/W ACK recevied by Client ticks the TX */
+
+static LIST_HEAD(mbox_cons);
+static DEFINE_MUTEX(con_mutex);
+
+static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
+{
+ int idx;
+ unsigned long flags;
+
+ spin_lock_irqsave(&chan->lock, flags);
+
+ /* See if there is any space left */
+ if (chan->msg_count == MBOX_TX_QUEUE_LEN) {
+ spin_unlock_irqrestore(&chan->lock, flags);
+ return -ENOMEM;
+ }
+
+ idx = chan->msg_free;
+ chan->msg_data[idx] = mssg;
+ chan->msg_count++;
+
+ if (idx == MBOX_TX_QUEUE_LEN - 1)
+ chan->msg_free = 0;
+ else
+ chan->msg_free++;
+
+ spin_unlock_irqrestore(&chan->lock, flags);
+
+ return idx;
+}
+
+static void msg_submit(struct mbox_chan *chan)
+{
+ unsigned count, idx;
+ unsigned long flags;
+ void *data;
+ int err;
+
+ spin_lock_irqsave(&chan->lock, flags);
+
+ if (!chan->msg_count || chan->active_req) {
+ spin_unlock_irqrestore(&chan->lock, flags);
+ return;
+ }
+
+ count = chan->msg_count;
+ idx = chan->msg_free;
+ if (idx >= count)
+ idx -= count;
+ else
+ idx += MBOX_TX_QUEUE_LEN - count;
+
+ data = chan->msg_data[idx];
+
+ /* Try to submit a message to the MBOX controller */
+ err = chan->mbox->ops->send_data(chan, data);
Probably this is discussed already, but again I missed to find it
in archives, so asking here. If the protocol has some payload associated
with the message and controller expects it to be in place before calling
send_data, we essentially end up not using this queue at all by waiting
in the protocol layer(may be in it's own queue)
Instead can we have some kind of chan->cl->prepare_data callback so that
client can prepare payload ? This in turn avoids to implement it's
*own Tx queue* and *reusing the mailbox queue*.
Or am I missing something ?
+ if (!err) {
+ chan->active_req = data;
+ chan->msg_count--;
+ }
+
+ spin_unlock_irqrestore(&chan->lock, flags);
+}
+
+static void tx_tick(struct mbox_chan *chan, int r)
+{
+ unsigned long flags;
+ void *mssg;
+
+ spin_lock_irqsave(&chan->lock, flags);
+ mssg = chan->active_req;
+ chan->active_req = NULL;
+ spin_unlock_irqrestore(&chan->lock, flags);
+
+ /* Submit next message */
+ msg_submit(chan);
+
+ /* Notify the client */
+ if (mssg && chan->cl->tx_done)
+ chan->cl->tx_done(chan->cl, mssg, r);
+
+ if (chan->cl->tx_block)
+ complete(&chan->tx_complete);
+}
+
+static void poll_txdone(unsigned long data)
+{
+ struct mbox_controller *mbox = (struct mbox_controller *)data;
+ bool txdone, resched = false;
+ int i;
+
+ for (i = 0; i < mbox->num_chans; i++) {
+ struct mbox_chan *chan = &mbox->chans[i];
+
+ if (chan->active_req && chan->cl) {
+ resched = true;
+ txdone = chan->mbox->ops->last_tx_done(chan);
+ if (txdone)
+ tx_tick(chan, 0);
What if all the active channels finished Tx(i.e. txdone = 1), we still have
resched = true and add a timer, not really harmful though. But IMO you can
move it to else part instead ?
Regards,
Sudeep
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
