[PATCH] soundwire: stream: Fix test for DP prepare complete

From: Richard Fitzgerald
Date: Fri Jun 18 2021 - 10:48:05 EST


In sdw_prep_deprep_slave_ports(), after the wait_for_completion()
the DP prepare status register is read. If this indicates that the
port is now prepared, the code should continue with the port setup.
It is irrelevant whether the wait_for_completion() timed out if the
port is now ready.

The previous implementation would always fail if the
wait_for_completion() timed out, even if the port was reporting
successful prepare.

This patch also fixes a minor bug where the return from sdw_read()
was not checked for error - any error code with LSBits clear could
be misinterpreted as a successful port prepare.

Fixes: 79df15b7d37c ("soundwire: Add helpers for ports operations")
Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/soundwire/stream.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 1eaedaaba094..1a18308f4ef4 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -422,7 +422,6 @@ static int sdw_prep_deprep_slave_ports(struct sdw_bus *bus,
struct completion *port_ready;
struct sdw_dpn_prop *dpn_prop;
struct sdw_prepare_ch prep_ch;
- unsigned int time_left;
bool intr = false;
int ret = 0, val;
u32 addr;
@@ -479,15 +478,15 @@ static int sdw_prep_deprep_slave_ports(struct sdw_bus *bus,

/* Wait for completion on port ready */
port_ready = &s_rt->slave->port_ready[prep_ch.num];
- time_left = wait_for_completion_timeout(port_ready,
- msecs_to_jiffies(dpn_prop->ch_prep_timeout));
+ wait_for_completion_timeout(port_ready,
+ msecs_to_jiffies(dpn_prop->ch_prep_timeout));

val = sdw_read(s_rt->slave, SDW_DPN_PREPARESTATUS(p_rt->num));
- val &= p_rt->ch_mask;
- if (!time_left || val) {
+ if ((val < 0) || (val & p_rt->ch_mask)) {
+ ret = (val < 0) ? val : -ETIMEDOUT;
dev_err(&s_rt->slave->dev,
- "Chn prep failed for port:%d\n", prep_ch.num);
- return -ETIMEDOUT;
+ "Chn prep failed for port %d: %d\n", prep_ch.num, ret);
+ return ret;
}
}

--
2.20.1