From abf308e82d73091ea03c6522fd128f54856273a6 Mon Sep 17 00:00:00 2001
From: bunnie <bunnie@kosagi.com>
Date: Sun, 2 May 2021 16:39:08 +0800
Subject: [PATCH] try to trace down issue #61

---
 services/gam/src/status.rs |  1 -
 services/rtc/src/main.rs   | 52 +++++++++++++++++++++++++-------------
 2 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/services/gam/src/status.rs b/services/gam/src/status.rs
index 440ddb32b..6f136640d 100644
--- a/services/gam/src/status.rs
+++ b/services/gam/src/status.rs
@@ -116,7 +116,6 @@ pub fn status_thread(canvas_gid_0: usize, canvas_gid_1: usize, canvas_gid_2: usi
 
     let mut rtc = rtc::Rtc::new(&xns).unwrap();
 
-    // TODO: debug why this is unreliable
     rtc.clear_wakeup_alarm().unwrap(); // clear any wakeup alarm state, if it was set
 
     rtc.hook_rtc_callback(dt_callback).unwrap();
diff --git a/services/rtc/src/main.rs b/services/rtc/src/main.rs
index 16bf770dd..d645ea20e 100644
--- a/services/rtc/src/main.rs
+++ b/services/rtc/src/main.rs
@@ -22,6 +22,8 @@ mod implementation {
     use xous_ipc::Buffer;
     use num_traits::ToPrimitive;
 
+    const BLOCKING_I2C_TIMEOUT_MS: u64 = 50;
+
     const ABRTCMC_I2C_ADR: u8 = 0x68;
     const ABRTCMC_CONTROL1: u8 = 0x00;
     bitflags! {
@@ -245,6 +247,7 @@ mod implementation {
         llio: Llio,
         rtc_alarm_enabled: bool,
         wakeup_alarm_enabled: bool,
+        ticktimer: ticktimer_server::Ticktimer,
     }
 
     impl Rtc {
@@ -256,6 +259,7 @@ mod implementation {
                 llio,
                 rtc_alarm_enabled: false,
                 wakeup_alarm_enabled: false,
+                ticktimer: ticktimer_server::Ticktimer::new().expect("can't connect to ticktimer"),
             }
         }
 
@@ -342,28 +346,40 @@ mod implementation {
             transaction.txbuf = Some(txbuf);
             transaction.txlen = 2;
             transaction.status = I2cStatus::RequestIncoming;
+            transaction.timeout_ms = 50;
 
-            while self.llio.poll_i2c_busy().unwrap() {
-                xous::yield_slice();
-            }
             let mut sent = false;
-            while !sent {
-                match self.llio.send_i2c_request(transaction) {
-                    Ok(status) => {
-                        match status {
-                            I2cStatus::ResponseInProgress => sent = true,
-                            I2cStatus::ResponseBusy => sent = false,
-                            _ => {log::error!("try_send_i2c unhandled response"); return false;},
-                        }
-                    }
-                    _ => {log::error!("try_send_i2c unhandled error"); return false;}
+            let max_retries = 2;
+            let mut retries = 0;
+            while (retries < max_retries) && !sent {
+                while self.llio.poll_i2c_busy().unwrap() {
+                    xous::yield_slice();
                 }
-                xous::yield_slice();
+                let start = self.ticktimer.elapsed_ms();
+                while !sent {
+                    match self.llio.send_i2c_request(transaction) {
+                        Ok(status) => {
+                            match status {
+                                I2cStatus::ResponseInProgress => sent = true,
+                                I2cStatus::ResponseBusy => sent = false,
+                                _ => {log::error!("try_send_i2c unhandled response"); return false;},
+                            }
+                        }
+                        _ => {log::error!("try_send_i2c unhandled error"); return false;}
+                    }
+                    if (self.ticktimer.elapsed_ms() - start > BLOCKING_I2C_TIMEOUT_MS) && !sent {
+                        log::error!("I2C blocking write timed out, try {}/{}", retries+1, max_retries);
+                        break;
+                    }
+                    xous::yield_slice();
+                }
+                while self.llio.poll_i2c_busy().unwrap() {
+                    xous::yield_slice();
+                }
+                retries += 1;
             }
-            while self.llio.poll_i2c_busy().unwrap() {
-                xous::yield_slice();
-            }
-            true
+
+            sent
         }
 
         /// wakeup self after designated number of seconds