From 658432e20391414491891450cdb9e3676269fae8 Mon Sep 17 00:00:00 2001
From: Judy Hsiao <judyhsiao@google.com>
Date: Wed, 14 Oct 2020 12:44:12 +0800
Subject: sound_card_init: skip boot time calibration when speakers may be hot

To protect the speaker, we need to skip boot calibration if
the latest speaker play time is less than 3 min.

The CL implements the following logic:
1. CRAS will store the latest shutdown timestamp
   /var/lib/cras/stop.
2. If "(Current time - the latest CRAS shutdown time) < 3 mins",
   we assume the speaker hasn't been replaced, and we don't need to
   recalibrate.
3. If (Current time - the latest CRAS shutdown time) >= 3 mins, we assume
   that the speakers are at thermal equilibrium with the
   temperature measured by the amplifier chip and thus
   it'd be safe to do a calibration.
4. If /var/lib/cras/stop is invalid, we set the speaker volume
   to low and delete the datastore as we can not assume that the
   speakers are not replaced or not heated.

BUG=b:169377240
TEST=tast run ${DUT_IP} soundcardinit.Max98390.*

Change-Id: I7769e955579be96ca7bf4ec048431b4ca61778bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/2475313
Tested-by: Judy Hsiao <judyhsiao@chromium.org>
Reviewed-by: Chih-Yang Hsia <paulhsia@chromium.org>
Commit-Queue: Judy Hsiao <judyhsiao@chromium.org>
Auto-Submit: Judy Hsiao <judyhsiao@chromium.org>
---
 sound_card_init/utils/src/lib.rs | 87 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 sound_card_init/utils/src/lib.rs

(limited to 'sound_card_init/utils/src/lib.rs')

diff --git a/sound_card_init/utils/src/lib.rs b/sound_card_init/utils/src/lib.rs
new file mode 100644
index 00000000..e8edce77
--- /dev/null
+++ b/sound_card_init/utils/src/lib.rs
@@ -0,0 +1,87 @@
+// Copyright 2020 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//! It contains common utils shared within sound_card_init.
+#![deny(missing_docs)]
+
+//! The error definitions for utils.
+pub mod error;
+
+use std::fs::File;
+use std::io::{prelude::*, BufReader, BufWriter};
+use std::path::PathBuf;
+use std::time::Duration;
+
+use crate::error::{Error, Result};
+
+/// The path of datastore.
+pub const DATASTORE_DIR: &str = "/var/lib/sound_card_init";
+
+fn duration_from_file(path: &PathBuf) -> Result<Duration> {
+    let reader =
+        BufReader::new(File::open(&path).map_err(|e| Error::FileIOFailed(path.clone(), e))?);
+    serde_yaml::from_reader(reader).map_err(|e| Error::SerdeError(path.clone(), e))
+}
+
+/// The utils to parse CRAS shutdown time file.
+pub mod shutdown_time {
+    use super::*;
+    // The path of CRAS shutdown time file.
+    const SHUTDOWN_TIME_FILE: &str = "/var/lib/cras/stop";
+
+    /// Reads the unix time from CRAS shutdown time file.
+    pub fn from_file() -> Result<Duration> {
+        duration_from_file(&PathBuf::from(SHUTDOWN_TIME_FILE))
+    }
+}
+
+/// The utils to create and parse sound_card_init run time file.
+pub mod run_time {
+    use std::time::SystemTime;
+
+    use super::*;
+    // The filename of sound_card_init run time file.
+    const RUN_TIME_FILE: &str = "run";
+
+    /// Returns the sound_card_init run time file existence.
+    pub fn exists(snd_card: &str) -> bool {
+        run_time_file(snd_card).exists()
+    }
+
+    /// Reads the unix time from sound_card_init run time file.
+    pub fn from_file(snd_card: &str) -> Result<Duration> {
+        duration_from_file(&run_time_file(snd_card))
+    }
+
+    /// Saves the current unix time to sound_card_init run time file.
+    pub fn now_to_file(snd_card: &str) -> Result<()> {
+        match SystemTime::now().duration_since(SystemTime::UNIX_EPOCH) {
+            Ok(t) => to_file(snd_card, t),
+            Err(e) => Err(Error::SystemTimeError(e)),
+        }
+    }
+
+    /// Saves the unix time to sound_card_init run time file.
+    pub fn to_file(snd_card: &str, duration: Duration) -> Result<()> {
+        let path = run_time_file(snd_card);
+        let mut writer =
+            BufWriter::new(File::create(&path).map_err(|e| Error::FileIOFailed(path.clone(), e))?);
+        writer
+            .write_all(
+                serde_yaml::to_string(&duration)
+                    .map_err(|e| Error::SerdeError(path.clone(), e))?
+                    .as_bytes(),
+            )
+            .map_err(|e| Error::FileIOFailed(path.clone(), e))?;
+        writer
+            .flush()
+            .map_err(|e| Error::FileIOFailed(path.clone(), e))?;
+        Ok(())
+    }
+
+    fn run_time_file(snd_card: &str) -> PathBuf {
+        PathBuf::from(DATASTORE_DIR)
+            .join(snd_card)
+            .join(RUN_TIME_FILE)
+    }
+}
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