From 38b986290230214382b244c77152f894a4d48c66 Mon Sep 17 00:00:00 2001
From: Augusto Fraga Giachero <augustofg96@gmail.com>
Date: Thu, 25 Jul 2019 08:31:06 -0600
Subject: [PATCH] arch/arm/src/lpc17xx_40xx/lpc17_40_i2c.c:  Abort I2C
 transfers if a timeout has occurred.  If a timeout has occurred in the middle
 of a I2C transfer, the next I2C interrupt should abort any transfers and send
 a stop condition to the corresponding I2C bus. Failed to do so will result in
 memory corruption / undefined behavior as priv->msgs points to a region of
 memory it doesn't owns anymore after lpc17_40_i2c_start returns.

---
 arch/arm/src/lpc17xx_40xx/lpc17_40_i2c.c | 31 ++++++++++++++++++------
 configs/imxrt1060-evk/README.txt         | 11 +++++++++
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/arch/arm/src/lpc17xx_40xx/lpc17_40_i2c.c b/arch/arm/src/lpc17xx_40xx/lpc17_40_i2c.c
index be28ac617a..74d60e8893 100644
--- a/arch/arm/src/lpc17xx_40xx/lpc17_40_i2c.c
+++ b/arch/arm/src/lpc17xx_40xx/lpc17_40_i2c.c
@@ -215,6 +215,10 @@ static int lpc17_40_i2c_start(struct lpc17_40_i2cdev_s *priv)
            priv->base + LPC17_40_I2C_CONCLR_OFFSET);
   putreg32(I2C_CONSET_STA, priv->base + LPC17_40_I2C_CONSET_OFFSET);
 
+  /* Initializes the I2C state machine to a known value */
+
+  priv->state = 0x00;
+
   (void)wd_start(priv->timeout, I2C_TIMEOUT, lpc17_40_i2c_timeout, 1,
                  (uint32_t)priv);
   nxsem_wait(&priv->wait);
@@ -275,7 +279,7 @@ static int lpc17_40_i2c_transfer(FAR struct i2c_master_s *dev,
   struct lpc17_40_i2cdev_s *priv = (struct lpc17_40_i2cdev_s *)dev;
   int ret;
 
-   DEBUGASSERT(dev != NULL && msgs != NULL && count > 0);
+  DEBUGASSERT(dev != NULL && msgs != NULL && count > 0);
 
   /* Get exclusive access to the I2C bus */
 
@@ -348,11 +352,20 @@ static int lpc17_40_i2c_interrupt(int irq, FAR void *context, void *arg)
   state = getreg32(priv->base + LPC17_40_I2C_STAT_OFFSET);
   msg  = priv->msgs;
 
-  priv->state = state;
-  state &= 0xf8;  /* state mask, only 0xX8 is possible */
+  /* Checks if a timeout occurred */
+
+  if (priv->state == 0xff)
+    {
+      state = 0xff;
+    }
+  else
+    {
+      priv->state = state;
+      state &= 0xf8;  /* state mask, only 0xX8 is possible */
+    }
+
   switch (state)
     {
-
     case 0x08:     /* A START condition has been transmitted. */
     case 0x10:     /* A Repeated START condition has been transmitted. */
       /* Set address */
@@ -402,7 +415,8 @@ static int lpc17_40_i2c_interrupt(int irq, FAR void *context, void *arg)
 
     case 0x50:  /* Data byte has been received; ACK has been returned. */
       priv->rdcnt++;
-      msg->buffer[priv->rdcnt - 1] = getreg32(priv->base + LPC17_40_I2C_BUFR_OFFSET);
+      msg->buffer[priv->rdcnt - 1] =
+        getreg32(priv->base + LPC17_40_I2C_BUFR_OFFSET);
 
       if (priv->rdcnt >= (msg->length - 1))
         {
@@ -411,7 +425,8 @@ static int lpc17_40_i2c_interrupt(int irq, FAR void *context, void *arg)
       break;
 
     case 0x58:  /* Data byte has been received; NACK has been returned. */
-      msg->buffer[priv->rdcnt] = getreg32(priv->base + LPC17_40_I2C_BUFR_OFFSET);
+      msg->buffer[priv->rdcnt] =
+        getreg32(priv->base + LPC17_40_I2C_BUFR_OFFSET);
       lpc17_40_stopnext(priv);
       break;
 
@@ -425,7 +440,7 @@ static int lpc17_40_i2c_interrupt(int irq, FAR void *context, void *arg)
   return OK;
 }
 
-/************************************************************************************
+/****************************************************************************
  * Name: lpc17_40_i2c_reset
  *
  * Description:
@@ -437,7 +452,7 @@ static int lpc17_40_i2c_interrupt(int irq, FAR void *context, void *arg)
  * Returned Value:
  *   Zero (OK) on success; a negated errno value on failure.
  *
- ************************************************************************************/
+ ****************************************************************************/
 
 #ifdef CONFIG_I2C_RESET
 static int lpc17_40_i2c_reset(FAR struct i2c_master_s * dev)
diff --git a/configs/imxrt1060-evk/README.txt b/configs/imxrt1060-evk/README.txt
index d9cd222bcc..956d865587 100644
--- a/configs/imxrt1060-evk/README.txt
+++ b/configs/imxrt1060-evk/README.txt
@@ -43,6 +43,7 @@ Contents
 
   o Serial Console
   o LEDs and buttons
+  o J-Link External Debug Probe
   o Configurations
     - Configuration sub-directories
 
@@ -115,6 +116,16 @@ LEDs and buttons
   Only the user button is available to the software.  It is sensed on the
   WAKEUP pin which will be pulled low when the button is pressed.
 
+
+J-Link External Debug Probe
+===========================
+
+  Install the J-Link Debug Host Tools and make sure they are in your search path.
+
+  Attach a J-Link 20-pin connector to J21. Check that jumpers J47 and J48 are
+  off (they are on by default when boards ship from the factory) to ensure SWD
+  signals are disconnected from the OpenSDA microcontroller.
+
 Configurations
 ==============