Re: [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when initializing a device

[Pierre-Louis Bossart]

Thanks for the review Vinod.

On 12/5/20 1:45 AM, Vinod Koul wrote:
On 03-12-20, 04:46, Bard Liao wrote:
From: Pierre-Louis Bossart <pierre-louis.boss...@linux.intel.com>
When a Slave device is resumed, it may resume the bus and restart the
enumeration. During that process, we absolutely don't want to call
regular read/write routines which will wait for the resume to
complete, otherwise a deadlock occurs.

Fixes: 60ee9be25571 ('soundwire: bus: add PM/no-PM versions of read/write 
functions')

Change looks okay, but not sure why this is a fix for adding no pm
version?

when we added the no_pm version, we missed the two cases below where 
sdw_update() was used and that creates a deadlock. To me that's a 
conceptual bug, we didn't fully use the no_pm versions, hence the Fixes tag.

It's ok to remove the tag if you don't think it's useful/relevant, what 
matters is that we agree on the content.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.boss...@linux.intel.com>
Reviewed-by: Rander Wang <rander.w...@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.l...@linux.intel.com>
---
  drivers/soundwire/bus.c | 16 ++++++++++++++--
  1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index d1e8c3a54976..60c42508c6c6 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -489,6 +489,18 @@ sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
                return buf;
  }
  
+static int sdw_update_no_pm(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
+{
+       int tmp;
+
+       tmp = sdw_read_no_pm(slave, addr);
+       if (tmp < 0)
+               return tmp;
+
+       tmp = (tmp & ~mask) | val;
+       return sdw_write_no_pm(slave, addr, tmp);
+}
+
  /**
   * sdw_nread() - Read "n" contiguous SDW Slave registers
   * @slave: SDW Slave
@@ -1256,7 +1268,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
        val = slave->prop.scp_int1_mask;
  
  	/* Enable SCP interrupts */
-       ret = sdw_update(slave, SDW_SCP_INTMASK1, val, val);
+       ret = sdw_update_no_pm(slave, SDW_SCP_INTMASK1, val, val);
        if (ret < 0) {
                dev_err(slave->bus->dev,
                        "SDW_SCP_INTMASK1 write failed:%d\n", ret);
@@ -1271,7 +1283,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
        val = prop->dp0_prop->imp_def_interrupts;
        val |= SDW_DP0_INT_PORT_READY | SDW_DP0_INT_BRA_FAILURE;
  
-	ret = sdw_update(slave, SDW_DP0_INTMASK, val, val);
+       ret = sdw_update_no_pm(slave, SDW_DP0_INTMASK, val, val);
        if (ret < 0)
                dev_err(slave->bus->dev,
                        "SDW_DP0_INTMASK read failed:%d\n", ret);
--
2.17.1