[BACKPORT 4.14.y 12/18] mailbox: reset txdone_method TXDONE_BY_POLL if client knows_txdone

From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: stable@vger.kernel.org
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-pm@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-omap@vger.kernel.org, linux-i2c@vger.kernel.org,
	linux-pci@vger.kernel.org, linux-mtd@lists.infradead.org
Subject: [BACKPORT 4.14.y 12/18] mailbox: reset txdone_method TXDONE_BY_POLL if client knows_txdone
Date: Thu,  5 Sep 2019 10:17:53 -0600	[thread overview]
Message-ID: <20190905161759.28036-13-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <20190905161759.28036-1-mathieu.poirier@linaro.org>

From: Sudeep Holla <sudeep.holla@arm.com>

commit 33cd7123ac0ba5360656ae27db453de5b9aa711f upstream

Currently the mailbox framework sets txdone_method to TXDONE_BY_POLL if
the controller sets txdone_by_poll. However some clients can have a
mechanism to do TXDONE_BY_ACK which they can specify by knows_txdone.
However, we endup setting both TXDONE_BY_POLL and TXDONE_BY_ACK in that
case. In such scenario, we may end up with below warnings as the tx
ticker is run both by mailbox framework and the client.

WARNING: CPU: 1 PID: 0 at kernel/time/hrtimer.c:805 hrtimer_forward+0x88/0xd8
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.12.0-rc5 #242
Hardware name: ARM LTD ARM Juno Development Platform
task: ffff8009768ca700 task.stack: ffff8009768f8000
PC is at hrtimer_forward+0x88/0xd8
LR is at txdone_hrtimer+0xd4/0xf8
Call trace:
 hrtimer_forward+0x88/0xd8
 __hrtimer_run_queues+0xe4/0x158
 hrtimer_interrupt+0xa4/0x220
 arch_timer_handler_phys+0x30/0x40
 handle_percpu_devid_irq+0x78/0x130
 generic_handle_irq+0x24/0x38
 __handle_domain_irq+0x5c/0xb8
 gic_handle_irq+0x54/0xa8

This patch fixes the issue by resetting TXDONE_BY_POLL if client has set
knows_txdone.

Cc: Alexey Klimov <alexey.klimov@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/mailbox/mailbox.c | 4 ++--
 drivers/mailbox/pcc.c     | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 44b49a2676f0..055c90b8253c 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -351,7 +351,7 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 	init_completion(&chan->tx_complete);
 
 	if (chan->txdone_method	== TXDONE_BY_POLL && cl->knows_txdone)
-		chan->txdone_method |= TXDONE_BY_ACK;
+		chan->txdone_method = TXDONE_BY_ACK;
 
 	spin_unlock_irqrestore(&chan->lock, flags);
 
@@ -420,7 +420,7 @@ void mbox_free_channel(struct mbox_chan *chan)
 	spin_lock_irqsave(&chan->lock, flags);
 	chan->cl = NULL;
 	chan->active_req = NULL;
-	if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
+	if (chan->txdone_method == TXDONE_BY_ACK)
 		chan->txdone_method = TXDONE_BY_POLL;
 
 	module_put(chan->mbox->dev->driver->owner);
diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index 9b7005e1345e..27c2294be51a 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -266,7 +266,7 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
 	init_completion(&chan->tx_complete);
 
 	if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
-		chan->txdone_method |= TXDONE_BY_ACK;
+		chan->txdone_method = TXDONE_BY_ACK;
 
 	spin_unlock_irqrestore(&chan->lock, flags);
 
@@ -312,7 +312,7 @@ void pcc_mbox_free_channel(struct mbox_chan *chan)
 	spin_lock_irqsave(&chan->lock, flags);
 	chan->cl = NULL;
 	chan->active_req = NULL;
-	if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
+	if (chan->txdone_method == TXDONE_BY_ACK)
 		chan->txdone_method = TXDONE_BY_POLL;
 
 	spin_unlock_irqrestore(&chan->lock, flags);
-- 
2.17.1

