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STM32, STM32 F7, and STM32 L4: Clone Freddie Chopin's I2C change to similar STM32 I2C drivers.

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Save elapsed time before handling I2C in stm32_i2c_sem_waitstop()
   This patch follows the same logic as in previous fix to
   stm32_i2c_sem_waitdone().
   It is possible that a context switch occurs after I2C registers are read
   but before elapsed time is saved in stm32_i2c_sem_waitstop(). It is then
   possible that the registers were read only once with "elapsed time"
   equal 0. When scheduler resumes this thread it is quite possible that
   now "elapsed time" will be well above timeout threshold. In that case
   the function returns and reports a timeout, even though the registers
   were not read "recently".
   Fix this by inverting the order of operations in the loop - save elapsed
   time before reading registers. This way a context switch anywhere in the
   loop will not cause an erroneous "timeout" error.
This commit is contained in:
David Sidrane 2017-03-10 05:07:39 -10:00
parent 3cd66af889
commit acaebb361b
5 changed files with 22 additions and 18 deletions
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8
arch/arm/src/stm32/stm32_i2c.c
View File

@ -729,6 +729,10 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
start = clock_systimer();
do
{
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
/* Check for STOP condition */
cr1 = stm32_i2c_getreg(priv, STM32_I2C_CR1_OFFSET);
@ -744,10 +748,6 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
{
return;
}
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
}
/* Loop until the stop is complete or a timeout occurs. */

7
arch/arm/src/stm32/stm32f30xxx_i2c.c
View File

@ -844,6 +844,10 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
start = clock_systimer();
do
{
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
/* Check for STOP condition */
cr = stm32_i2c_getreg32(priv, STM32_I2C_CR2_OFFSET);
@ -860,9 +864,6 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
return;
}
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
}
/* Loop until the stop is complete or a timeout occurs. */

7
arch/arm/src/stm32/stm32f40xxx_i2c.c
View File

@ -731,6 +731,10 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
start = clock_systimer();
do
{
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
/* Check for STOP condition */
cr1 = stm32_i2c_getreg(priv, STM32_I2C_CR1_OFFSET);
@ -747,9 +751,6 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
return;
}
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
}
/* Loop until the stop is complete or a timeout occurs. */

9
arch/arm/src/stm32f7/stm32_i2c.c
View File

@ -7,7 +7,7 @@
*
* With extensions and modifications for the F1, F2, and F4 by:
*
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
* Copyright (C) 2016-2017 Gregory Nutt. All rights reserved.
* Authors: Gregroy Nutt <gnutt@nuttx.org>
* John Wharington
* David Sidrane <david_s5@nscdg.com>
@ -1034,6 +1034,10 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
start = clock_systimer();
do
{
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
/* Check for STOP condition */
cr = stm32_i2c_getreg32(priv, STM32_I2C_CR2_OFFSET);
@ -1050,9 +1054,6 @@ static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
return;
}
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
}
/* Loop until the stop is complete or a timeout occurs. */

7
arch/arm/src/stm32l4/stm32l4_i2c.c
View File

@ -788,6 +788,10 @@ static inline void stm32l4_i2c_sem_waitstop(FAR struct stm32l4_i2c_priv_s *priv)
start = clock_systimer();
do
{
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
/* Check for STOP condition */
cr = stm32l4_i2c_getreg32(priv, STM32L4_I2C_CR2_OFFSET);
@ -804,9 +808,6 @@ static inline void stm32l4_i2c_sem_waitstop(FAR struct stm32l4_i2c_priv_s *priv)
return;
}
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
}
/* Loop until the stop is complete or a timeout occurs. */