[PATCH v2 2/7] mailbox: mpfs: switch to txdone_poll

From: Conor Dooley
Date: Fri Jan 20 2023 - 09:40:22 EST


The system controller on PolarFire SoC has no interrupt to signify that
the TX has been completed. The interrupt instead signals that a service
requested by the mailbox client has succeeded. If a service fails, there
will be no interrupt delivered.

Switch to polling the busy register to determine whether transmission
has completed.

Fixes: 83d7b1560810 ("mbox: add polarfire soc system controller mailbox")
Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
---
drivers/mailbox/mailbox-mpfs.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/mailbox/mailbox-mpfs.c b/drivers/mailbox/mailbox-mpfs.c
index d37560e91116..e0e825bdbad9 100644
--- a/drivers/mailbox/mailbox-mpfs.c
+++ b/drivers/mailbox/mailbox-mpfs.c
@@ -79,6 +79,13 @@ static bool mpfs_mbox_busy(struct mpfs_mbox *mbox)
return status & SCB_STATUS_BUSY_MASK;
}

+static bool mpfs_mbox_last_tx_done(struct mbox_chan *chan)
+{
+ struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
+
+ return !mpfs_mbox_busy(mbox);
+}
+
static int mpfs_mbox_send_data(struct mbox_chan *chan, void *data)
{
struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
@@ -183,7 +190,6 @@ static irqreturn_t mpfs_mbox_inbox_isr(int irq, void *data)

mpfs_mbox_rx_data(chan);

- mbox_chan_txdone(chan, 0);
return IRQ_HANDLED;
}

@@ -213,6 +219,7 @@ static const struct mbox_chan_ops mpfs_mbox_ops = {
.send_data = mpfs_mbox_send_data,
.startup = mpfs_mbox_startup,
.shutdown = mpfs_mbox_shutdown,
+ .last_tx_done = mpfs_mbox_last_tx_done,
};

static int mpfs_mbox_probe(struct platform_device *pdev)
@@ -248,7 +255,8 @@ static int mpfs_mbox_probe(struct platform_device *pdev)
mbox->controller.num_chans = 1;
mbox->controller.chans = mbox->chans;
mbox->controller.ops = &mpfs_mbox_ops;
- mbox->controller.txdone_irq = true;
+ mbox->controller.txdone_poll = true;
+ mbox->controller.txpoll_period = 10u;

ret = devm_mbox_controller_register(&pdev->dev, &mbox->controller);
if (ret) {
--
2.39.0