soundwire: stream: Fix test for DP prepare complete

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@opensource.cirrus.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210618144745.30629-1-rf@opensource.cirrus.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 1eaedaaba09441cc5086d424463e1fae0014d226..1a18308f4ef4f2c22c16d1ea1529660031d6650b 100644 (file)
--- 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;
                }
        }