Re: [RFC PATCH 32/40] soundwire: intel: add helper for initialization

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On 7/26/19 5:42 AM, Cezary Rojewski wrote:
On 2019-07-26 01:40, Pierre-Louis Bossart wrote:
Move code to helper for reuse in power management routines

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
  drivers/soundwire/intel.c | 16 +++++++++++-----
  1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index c40ab443e723..215dc81cdf73 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -984,6 +984,15 @@ static struct sdw_master_ops sdw_intel_ops = {
      .post_bank_switch = intel_post_bank_switch,
  };
+static int intel_init(struct sdw_intel *sdw)
+{
+    /* Initialize shim and controller */
+    intel_link_power_up(sdw);
+    intel_shim_init(sdw);
+
+    return sdw_cdns_init(&sdw->cdns);
+}

Why don't we check polling status for _link_power_up? I've already met slow starting devices in the past. If polling fails and -EAGAIN is returned, flow of initialization should react appropriately e.g. poll till MAX_TIMEOUT of some sort -or- collapse.

The code does what it states, it initializes the Intel and Cadence IPs.

What you are referring to is a different problem: once the bus starts, then Slave devices will report as attached, and will be enumerated. This will take time. The devices I tested show up immediately and within a couple of ms the bus is operational. But MIPI allows to the sync to take up to 4096 frames, which is 85ms with a 48kHz frame rate, so yes we do need to look into this.

We currently do not have a notification that tells us the bus is back to normal, that's a design flaw - see the last patch of the series where I kicked the can down the road but adding an artificial delay.

So yes good point indeed but on the wrong patch :-)
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