ARMmbed
/
mbed-os
mirror of https://github.com/ARMmbed/mbed-os.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

[Nuvoton] Remove special handling for dummy interrupt in lp_ticker 

It is because dummy interrupt is very rare or pending time caused by it
is very short.
pull/7029/head
ccli8 2018-06-28 16:27:37 +08:00
parent 310a1fe318
commit 1fa3374310
4 changed files with 60 additions and 80 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
targets/TARGET_NUVOTON/TARGET_M451/lp_ticker.c
View File

@ -54,8 +54,21 @@ static volatile uint16_t ticker_inited = 0;
#define TMR_CMP_MIN 2
#define TMR_CMP_MAX 0xFFFFFFu
/* NOTE: When system clock is higher than timer clock, we need to add 3 engine clock
* (recommended by designer) delay to wait for above timer control to take effect. */
/* Synchronization issue with LXT/LIRC-clocked Timer
*
* PCLK : typical HCLK/2
* ECLK (engine clock) : LXT/LIRC for Timer used to implement lp_ticker
*
* When system clock is higher than Timer clock (LXT/LIRC), we need to add delay for ECLK
* domain to take effect:
* 1. Write : typical 1PCLK + 2ECLK
* Read-check doesn't work because it just checks PCLK domain and doesn't check into
* ECLK domain.
* 2. Clear interrupt flag : typical 2PCLK
* It is very rare that we would meet dummy interrupt and get stuck in ISR until
* 'clear interrupt flag' takes effect. The issue is ignorable because the pending
* time is very short (at most 1 dummy interrupt). We won't take special handling for it.
*/
void lp_ticker_init(void)
{
@ -214,25 +227,7 @@ const ticker_info_t* lp_ticker_get_info()
static void tmr1_vec(void)
{
/* NOTE: Avoid blocking in ISR due to wait for "clear interrupt flag"
*
* "clear interrupt flag" needs wait to take effect which isn't added here to avoid
* blocking in ISR.
*
* Continuing above, we will get stuck in ISR due to dummy interrupt until
* "clear interrupt flag" takes effect. To avoid it, we disable interrupt here and enable
* interrupt in lp_ticker_fire_interrupt/lp_ticker_set_interrupt. There is another risk
* that we may get stuck in a loop of ISR and lp_ticker_fire_interrupt/
* lp_ticker_set_interrupt (called by lp_ticker_irq_handler), but actually we don't:
* 1. When lp_ticker_fire_interrupt gets called, it means there is a past event and so this
* interrupt isn't dummy.
* 2. With LPTICKER_DELAY_TICKS enabled, it is lp_ticker_set_interrupt_wrapper rather than
* lp_ticker_set_interrupt that gets straight called. lp_ticker_set_interrupt_wrapper
* guarantees that lp_ticker_set_interrupt won't get re-called in LPTICKER_DELAY_TICKS ticks
* which is just enough for "clear interrupt flag" to take effect.
*/
lp_ticker_clear_interrupt();
lp_ticker_disable_interrupt();
// NOTE: lp_ticker_set_interrupt() may get called in lp_ticker_irq_handler();
lp_ticker_irq_handler();

35
targets/TARGET_NUVOTON/TARGET_M480/lp_ticker.c
View File

@ -54,8 +54,21 @@ static volatile uint16_t ticker_inited = 0;
#define TMR_CMP_MIN 2
#define TMR_CMP_MAX 0xFFFFFFu
/* NOTE: When system clock is higher than timer clock, we need to add 3 engine clock
* (recommended by designer) delay to wait for above timer control to take effect. */
/* Synchronization issue with LXT/LIRC-clocked Timer
*
* PCLK : typical HCLK/2
* ECLK (engine clock) : LXT/LIRC for Timer used to implement lp_ticker
*
* When system clock is higher than Timer clock (LXT/LIRC), we need to add delay for ECLK
* domain to take effect:
* 1. Write : typical 1PCLK + 2ECLK
* Read-check doesn't work because it just checks PCLK domain and doesn't check into
* ECLK domain.
* 2. Clear interrupt flag : typical 2PCLK
* It is very rare that we would meet dummy interrupt and get stuck in ISR until
* 'clear interrupt flag' takes effect. The issue is ignorable because the pending
* time is very short (at most 1 dummy interrupt). We won't take special handling for it.
*/
void lp_ticker_init(void)
{
@ -214,25 +227,7 @@ const ticker_info_t* lp_ticker_get_info()
static void tmr1_vec(void)
{
/* NOTE: Avoid blocking in ISR due to wait for "clear interrupt flag"
*
* "clear interrupt flag" needs wait to take effect which isn't added here to avoid
* blocking in ISR.
*
* Continuing above, we will get stuck in ISR due to dummy interrupt until
* "clear interrupt flag" takes effect. To avoid it, we disable interrupt here and enable
* interrupt in lp_ticker_fire_interrupt/lp_ticker_set_interrupt. There is another risk
* that we may get stuck in a loop of ISR and lp_ticker_fire_interrupt/
* lp_ticker_set_interrupt (called by lp_ticker_irq_handler), but actually we don't:
* 1. When lp_ticker_fire_interrupt gets called, it means there is a past event and so this
* interrupt isn't dummy.
* 2. With LPTICKER_DELAY_TICKS enabled, it is lp_ticker_set_interrupt_wrapper rather than
* lp_ticker_set_interrupt that gets straight called. lp_ticker_set_interrupt_wrapper
* guarantees that lp_ticker_set_interrupt won't get re-called in LPTICKER_DELAY_TICKS ticks
* which is just enough for "clear interrupt flag" to take effect.
*/
lp_ticker_clear_interrupt();
lp_ticker_disable_interrupt();
// NOTE: lp_ticker_set_interrupt() may get called in lp_ticker_irq_handler();
lp_ticker_irq_handler();

35
targets/TARGET_NUVOTON/TARGET_NANO100/lp_ticker.c
View File

@ -56,8 +56,21 @@ static volatile uint16_t ticker_inited = 0;
#define TMR_CMP_MIN 2
#define TMR_CMP_MAX 0xFFFFFFu
/* NOTE: When system clock is higher than timer clock, we need to add 3 engine clock
* (recommended by designer) delay to wait for above timer control to take effect. */
/* Synchronization issue with LXT/LIRC-clocked Timer
*
* PCLK : typical HCLK/2
* ECLK (engine clock) : LXT/LIRC for Timer used to implement lp_ticker
*
* When system clock is higher than Timer clock (LXT/LIRC), we need to add delay for ECLK
* domain to take effect:
* 1. Write : typical 1PCLK + 2ECLK
* Read-check doesn't work because it just checks PCLK domain and doesn't check into
* ECLK domain.
* 2. Clear interrupt flag : typical 2PCLK
* It is very rare that we would meet dummy interrupt and get stuck in ISR until
* 'clear interrupt flag' takes effect. The issue is ignorable because the pending
* time is very short (at most 1 dummy interrupt). We won't take special handling for it.
*/
void lp_ticker_init(void)
{
@ -218,25 +231,7 @@ const ticker_info_t* lp_ticker_get_info()
void TMR1_IRQHandler(void)
{
/* NOTE: Avoid blocking in ISR due to wait for "clear interrupt flag"
*
* "clear interrupt flag" needs wait to take effect which isn't added here to avoid
* blocking in ISR.
*
* Continuing above, we will get stuck in ISR due to dummy interrupt until
* "clear interrupt flag" takes effect. To avoid it, we disable interrupt here and enable
* interrupt in lp_ticker_fire_interrupt/lp_ticker_set_interrupt. There is another risk
* that we may get stuck in a loop of ISR and lp_ticker_fire_interrupt/
* lp_ticker_set_interrupt (called by lp_ticker_irq_handler), but actually we don't:
* 1. When lp_ticker_fire_interrupt gets called, it means there is a past event and so this
* interrupt isn't dummy.
* 2. With LPTICKER_DELAY_TICKS enabled, it is lp_ticker_set_interrupt_wrapper rather than
* lp_ticker_set_interrupt that gets straight called. lp_ticker_set_interrupt_wrapper
* guarantees that lp_ticker_set_interrupt won't get re-called in LPTICKER_DELAY_TICKS ticks
* which is just enough for "clear interrupt flag" to take effect.
*/
lp_ticker_clear_interrupt();
lp_ticker_disable_interrupt();
// NOTE: lp_ticker_set_interrupt() may get called in lp_ticker_irq_handler();
lp_ticker_irq_handler();

35
targets/TARGET_NUVOTON/TARGET_NUC472/lp_ticker.c
View File

@ -54,8 +54,21 @@ static volatile uint16_t ticker_inited = 0;
#define TMR_CMP_MIN 2
#define TMR_CMP_MAX 0xFFFFFFu
/* NOTE: When system clock is higher than timer clock, we need to add 3 engine clock
* (recommended by designer) delay to wait for above timer control to take effect. */
/* Synchronization issue with LXT/LIRC-clocked Timer
*
* PCLK : typical HCLK/2
* ECLK (engine clock) : LXT/LIRC for Timer used to implement lp_ticker
*
* When system clock is higher than Timer clock (LXT/LIRC), we need to add delay for ECLK
* domain to take effect:
* 1. Write : typical 1PCLK + 2ECLK
* Read-check doesn't work because it just checks PCLK domain and doesn't check into
* ECLK domain.
* 2. Clear interrupt flag : typical 2PCLK
* It is very rare that we would meet dummy interrupt and get stuck in ISR until
* 'clear interrupt flag' takes effect. The issue is ignorable because the pending
* time is very short (at most 1 dummy interrupt). We won't take special handling for it.
*/
void lp_ticker_init(void)
{
@ -213,25 +226,7 @@ const ticker_info_t* lp_ticker_get_info()
static void tmr1_vec(void)
{
/* NOTE: Avoid blocking in ISR due to wait for "clear interrupt flag"
*
* "clear interrupt flag" needs wait to take effect which isn't added here to avoid
* blocking in ISR.
*
* Continuing above, we will get stuck in ISR due to dummy interrupt until
* "clear interrupt flag" takes effect. To avoid it, we disable interrupt here and enable
* interrupt in lp_ticker_fire_interrupt/lp_ticker_set_interrupt. There is another risk
* that we may get stuck in a loop of ISR and lp_ticker_fire_interrupt/
* lp_ticker_set_interrupt (called by lp_ticker_irq_handler), but actually we don't:
* 1. When lp_ticker_fire_interrupt gets called, it means there is a past event and so this
* interrupt isn't dummy.
* 2. With LPTICKER_DELAY_TICKS enabled, it is lp_ticker_set_interrupt_wrapper rather than
* lp_ticker_set_interrupt that gets straight called. lp_ticker_set_interrupt_wrapper
* guarantees that lp_ticker_set_interrupt won't get re-called in LPTICKER_DELAY_TICKS ticks
* which is just enough for "clear interrupt flag" to take effect.
*/
lp_ticker_clear_interrupt();
lp_ticker_disable_interrupt();
// NOTE: lp_ticker_set_interrupt() may get called in lp_ticker_irq_handler();
lp_ticker_irq_handler();