linux-kernel - [RESEND PATCH] firmware: ti_sci: Fix polled mode during system suspend

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Date:   Fri, 21 Oct 2022 21:57:04 +0300
From:   Georgi Vlaev <g-vlaev@...com>
To:     Nishanth Menon <nm@...com>, Tero Kristo <kristo@...nel.org>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        Vignesh Raghavendra <vigneshr@...com>,
        Vibhore Vardhan <vibhore@...com>
CC:     <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, Georgi Vlaev <g-vlaev@...com>
Subject: [RESEND PATCH] firmware: ti_sci: Fix polled mode during system suspend

Commit b9e8a7d950ff ("firmware: ti_sci: Switch transport to polled
mode during system suspend") uses read_poll_timeout_atomic() macro
in ti_sci_do_xfer() to wait for completion when the system is
suspending. The break condition of the macro is set to "true" which
will cause it break immediately when evaluated, likely before the
TISCI xfer is completed, and always return 0. We want to poll here
until "done_state == true".

1) Change the break condition of read_poll_timeout_atomic() to
the bool variable "done_state".

2) The read_poll_timeout_atomic() returns 0 if the break condition
is met or -ETIMEDOUT if not. Since our break condition has changed
to "done_state", we also don't have to check for "!done_state" when
evaluating the return value.

Fixes: b9e8a7d950ff ("firmware: ti_sci: Switch transport to polled mode during system suspend")

Signed-off-by: Georgi Vlaev <g-vlaev@...com>
---
 drivers/firmware/ti_sci.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index ebc32bbd9b83..6281e7153b47 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -429,15 +429,14 @@ static inline int ti_sci_do_xfer(struct ti_sci_info *info,
 		 * during noirq phase, so we must manually poll the completion.
 		 */
 		ret = read_poll_timeout_atomic(try_wait_for_completion, done_state,
-					       true, 1,
+					       done_state, 1,
 					       info->desc->max_rx_timeout_ms * 1000,
 					       false, &xfer->done);
 	}

-	if (ret == -ETIMEDOUT || !done_state) {
+	if (ret == -ETIMEDOUT)
 		dev_err(dev, "Mbox timedout in resp(caller: %pS)\n",
 			(void *)_RET_IP_);
-	}

 	/*
 	 * NOTE: we might prefer not to need the mailbox ticker to manage the

base-commit: 4d48f589d294ddc5e01d3b0dc7cecc55324c05ca
-- 
2.30.2