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driver: refactor the arcv2 timer0 driver

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refactor the arcv2 timer0 driver according to
the latest changes in sys clock dirver.

Signed-off-by: Wayne Ren <wei.ren@synopsys.com>
This commit is contained in:
Wayne Ren 2018-11-22 17:55:27 +08:00 • committed by Anas Nashif
commit fceaf894c4
2 changed files with 95 additions and 435 deletions
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1
drivers/timer/Kconfig
View file

@ -117,6 +117,7 @@ config ARCV2_TIMER
bool "ARC Timer" bool "ARC Timer"
default y default y
depends on ARC depends on ARC
select TICKLESS_CAPABLE
help help
This module implements a kernel device driver for the ARCv2 processor timer 0 This module implements a kernel device driver for the ARCv2 processor timer 0
and provides the standard "system clock driver" interfaces. and provides the standard "system clock driver" interfaces.

529
drivers/timer/arcv2_timer0.c
View file

@ -1,94 +1,46 @@
/* /*
* Copyright (c) 2014-2015 Wind River Systems, Inc. * Copyright (c) 2014-2015 Wind River Systems, Inc.
* Copyright (c) 2018 Synopsys Inc, Inc.
* *
* SPDX-License-Identifier: Apache-2.0 * SPDX-License-Identifier: Apache-2.0
*/ */
/**
* @file
* @brief ARC Timer0 device driver
*
* This module implements a kernel device driver for the ARCv2 processor Timer0
* and provides the standard "system clock driver" interfaces.
*
* If the TICKLESS_IDLE kernel configuration option is enabled, the timer may
* be programmed to wake the system in N >= TICKLESS_IDLE_THRESH ticks. The
* kernel invokes _timer_idle_enter() to program the up counter to trigger an
* interrupt in N ticks. When the timer expires (or when another interrupt is
* detected), the kernel's interrupt stub invokes z_clock_idle_exit() to leave
* the tickless idle state.
*
* @internal
* The ARCv2 processor timer provides a 32-bit incrementing, wrap-to-zero
* counter.
*
* Factors that increase the driver's tickless idle complexity:
* 1. As the Timer0 up-counter is a 32-bit value, the number of ticks for which
* the system can be in tickless idle is limited to 'max_system_ticks'.
*
* 2. The act of entering tickless idle may potentially straddle a tick
* boundary. This can be detected in _timer_idle_enter() after Timer0 is
* programmed with the new limit and acted upon in z_clock_idle_exit().
*
* 3. Tickless idle may be prematurely aborted due to a straddled tick. See
* previous factor.
*
* 4. Tickless idle may end naturally. This is detected and handled in
* z_clock_idle_exit().
*
* 5. Tickless idle may be prematurely aborted due to a non-timer interrupt.
* If this occurs, Timer0 is reprogrammed to trigger at the next tick.
* @endinternal
*/
#include <kernel.h>
#include <arch/cpu.h>
#include <toolchain.h>
#include <linker/sections.h>
#include <misc/__assert.h>
#include <arch/arc/v2/aux_regs.h>
#include <sys_clock.h>
#include <drivers/system_timer.h> #include <drivers/system_timer.h>
#include <stdbool.h> #include <sys_clock.h>
#include <misc/__assert.h> #include <spinlock.h>
#include <arch/arc/v2/aux_regs.h>
#include <soc.h>
/* /*
* note: This implementation assumes Timer0 is present. Be sure * note: This implementation assumes Timer0 is present. Be sure
* to build the ARC CPU with Timer0. * to build the ARC CPU with Timer0.
*/ */
#include <soc.h>
#include "legacy_api.h"
#define _ARC_V2_TMR_CTRL_IE 0x1 /* interrupt enable */ #define _ARC_V2_TMR_CTRL_IE 0x1 /* interrupt enable */
#define _ARC_V2_TMR_CTRL_NH 0x2 /* count only while not halted */ #define _ARC_V2_TMR_CTRL_NH 0x2 /* count only while not halted */
#define _ARC_V2_TMR_CTRL_W 0x4 /* watchdog mode enable */ #define _ARC_V2_TMR_CTRL_W 0x4 /* watchdog mode enable */
#define _ARC_V2_TMR_CTRL_IP 0x8 /* interrupt pending flag */ #define _ARC_V2_TMR_CTRL_IP 0x8 /* interrupt pending flag */
/* running total of timer count */ /* Minimum cycles in the future to try to program. */
static u32_t __noinit cycles_per_tick; #define MIN_DELAY 1024
static volatile u32_t accumulated_cycle_count; #define COUNTER_MAX 0xffffffff
static s32_t _sys_idle_elapsed_ticks = 1; #define TIMER_STOPPED 0x0
#define CYC_PER_TICK (CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC \
/ CONFIG_SYS_CLOCK_TICKS_PER_SEC)
#ifdef CONFIG_TICKLESS_IDLE #define MAX_TICKS ((COUNTER_MAX / CYC_PER_TICK) - 1)
static u32_t __noinit max_system_ticks; #define MAX_CYCLES (MAX_TICKS * CYC_PER_TICK)
static u32_t __noinit programmed_ticks;
#ifndef CONFIG_TICKLESS_KERNEL
static u32_t __noinit programmed_limit;
static int straddled_tick_on_idle_enter;
#endif
#endif
#ifdef CONFIG_TICKLESS_KERNEL #define TICKLESS (IS_ENABLED(CONFIG_TICKLESS_KERNEL) && \
static volatile int timer_expired; !IS_ENABLED(CONFIG_QEMU_TICKLESS_WORKAROUND))
#endif
#ifdef CONFIG_DEVICE_POWER_MANAGEMENT static struct k_spinlock lock;
static u32_t arcv2_timer0_device_power_state;
static u32_t saved_limit; static u32_t last_load;
static u32_t saved_control;
#endif static u32_t cycle_count;
static volatile u32_t ctrl_cache; /* overflow bit clears on read! */
/** /**
* *
@ -156,322 +108,44 @@ static ALWAYS_INLINE void timer0_limit_register_set(u32_t count)
_arc_v2_aux_reg_write(_ARC_V2_TMR0_LIMIT, count); _arc_v2_aux_reg_write(_ARC_V2_TMR0_LIMIT, count);
} }
#ifdef CONFIG_TICKLESS_IDLE static u32_t elapsed(void)
static ALWAYS_INLINE void update_accumulated_count(void)
{ {
accumulated_cycle_count += (_sys_idle_elapsed_ticks * cycles_per_tick); u32_t val, ov;
}
#else /* CONFIG_TICKLESS_IDLE */
static ALWAYS_INLINE void update_accumulated_count(void)
{
accumulated_cycle_count += cycles_per_tick;
}
#endif /* CONFIG_TICKLESS_IDLE */
#ifdef CONFIG_TICKLESS_KERNEL do {
static inline void program_max_cycles(void) val = timer0_count_register_get();
{ ctrl_cache = timer0_control_register_get();
timer0_limit_register_set(max_system_ticks * cycles_per_tick); } while (timer0_count_register_get() < val);
timer_expired = 0;
ov = (ctrl_cache & _ARC_V2_TMR_CTRL_IP) ? last_load : 0;
return val + ov;
} }
#endif
/** /**
* *
* @brief System clock periodic tick handler * @brief System clock periodic tick handler
* *
* This routine handles the system clock periodic tick interrupt. It always * This routine handles the system clock tick interrupt. It always
* announces one tick. * announces one tick when TICKLESS is not enabled, or multiple ticks
* when TICKLESS is enabled.
* *
* @return N/A * @return N/A
*/ */
void _timer_int_handler(void *unused) void _timer_int_handler(void *unused)
{ {
#ifdef CONFIG_EXECUTION_BENCHMARKING
extern void read_timer_start_of_tick_handler(void);
read_timer_start_of_tick_handler();
#endif
ARG_UNUSED(unused); ARG_UNUSED(unused);
u32_t dticks;
/* clear the interrupt by writing 0 to IP bit of the control register */ /* clear the interrupt by writing 0 to IP bit of the control register */
timer0_control_register_set(_ARC_V2_TMR_CTRL_NH | _ARC_V2_TMR_CTRL_IE); timer0_control_register_set(_ARC_V2_TMR_CTRL_NH | _ARC_V2_TMR_CTRL_IE);
#ifdef CONFIG_TICKLESS_KERNEL cycle_count += last_load;
if (!programmed_ticks) { dticks = last_load / CYC_PER_TICK;
if (_sys_clock_always_on) {
z_tick_set(z_clock_uptime());
program_max_cycles();
}
return;
}
_sys_idle_elapsed_ticks = programmed_ticks; z_clock_announce(TICKLESS ? dticks : 1);
/*
* Clear programmed ticks before announcing elapsed time so
* that recursive calls to _update_elapsed_time() will not
* announce already consumed elapsed time
*/
programmed_ticks = 0;
timer_expired = 1;
z_clock_announce(_sys_idle_elapsed_ticks);
/* z_clock_announce() could cause new programming */
if (!programmed_ticks && _sys_clock_always_on) {
z_tick_set(z_clock_uptime());
program_max_cycles();
}
#else
#if defined(CONFIG_TICKLESS_IDLE)
timer0_limit_register_set(cycles_per_tick - 1);
__ASSERT_EVAL({},
u32_t timer_count = timer0_count_register_get(),
timer_count <= (cycles_per_tick - 1),
"timer_count: %d, limit %d\n", timer_count, cycles_per_tick - 1);
_sys_idle_elapsed_ticks = 1;
z_clock_announce(_sys_idle_elapsed_ticks);
#else
z_clock_announce(_sys_idle_elapsed_ticks);
#endif
update_accumulated_count();
#endif
#ifdef CONFIG_EXECUTION_BENCHMARKING
extern void read_timer_end_of_tick_handler(void);
read_timer_end_of_tick_handler();
#endif
} }
#ifdef CONFIG_TICKLESS_KERNEL
u32_t _get_program_time(void)
{
return programmed_ticks;
}
u32_t _get_remaining_program_time(void)
{
if (programmed_ticks == 0) {
return 0;
}
if (timer0_control_register_get() & _ARC_V2_TMR_CTRL_IP) {
return 0;
}
return programmed_ticks -
(timer0_count_register_get() / cycles_per_tick);
}
u32_t _get_elapsed_program_time(void)
{
if (programmed_ticks == 0) {
return 0;
}
if (timer0_control_register_get() & _ARC_V2_TMR_CTRL_IP) {
return programmed_ticks;
}
return timer0_count_register_get() / cycles_per_tick;
}
void _set_time(u32_t time)
{
if (!time) {
programmed_ticks = 0U;
return;
}
programmed_ticks = time > max_system_ticks ? max_system_ticks : time;
z_tick_set(z_clock_uptime());
timer0_limit_register_set(programmed_ticks * cycles_per_tick);
timer0_count_register_set(0);
timer_expired = 0;
}
void _enable_sys_clock(void)
{
if (!programmed_ticks) {
program_max_cycles();
}
}
static inline u64_t get_elapsed_count(void)
{
u64_t elapsed;
if (timer_expired
|| (timer0_control_register_get() & _ARC_V2_TMR_CTRL_IP)) {
elapsed = timer0_limit_register_get();
} else {
elapsed = timer0_count_register_get();
}
elapsed += z_tick_get() * cycles_per_tick;
return elapsed;
}
u64_t z_clock_uptime(void)
{
return get_elapsed_count() / cycles_per_tick;
}
#endif
#if defined(CONFIG_TICKLESS_IDLE)
/*
* @brief initialize the tickless idle feature
*
* This routine initializes the tickless idle feature.
*
* @return N/A
*/
static void tickless_idle_init(void)
{
/* calculate the max number of ticks with this 32-bit H/W counter */
max_system_ticks = 0xffffffff / cycles_per_tick;
}
/*
* @brief Place the system timer into idle state
*
* Re-program the timer to enter into the idle state for either the given
* number of ticks or the maximum number of ticks that can be programmed
* into hardware.
*
* @return N/A
*/
void _timer_idle_enter(s32_t ticks)
{
#ifdef CONFIG_TICKLESS_KERNEL
if (ticks != K_FOREVER) {
/* Need to reprogram only if current program is smaller */
if (ticks > programmed_ticks) {
_set_time(ticks);
}
} else {
programmed_ticks = 0;
timer0_control_register_set(timer0_control_register_get() &
~_ARC_V2_TMR_CTRL_IE);
}
#else
u32_t status;
if ((ticks == K_FOREVER) || (ticks > max_system_ticks)) {
/*
* The number of cycles until the timer must fire next might not fit
* in the 32-bit counter register. To work around this, program
* the counter to fire in the maximum number of ticks.
*/
ticks = max_system_ticks;
}
programmed_ticks = ticks;
programmed_limit = (programmed_ticks * cycles_per_tick) - 1;
timer0_limit_register_set(programmed_limit);
/*
* If Timer0's IP bit is set, then it is known that we have straddled
* a tick boundary while entering tickless idle.
*/
status = timer0_control_register_get();
if (status & _ARC_V2_TMR_CTRL_IP) {
straddled_tick_on_idle_enter = 1;
}
__ASSERT_EVAL({},
u32_t timer_count = timer0_count_register_get(),
timer_count <= programmed_limit,
"timer_count: %d, limit %d\n", timer_count, programmed_limit);
#endif
}
/*
* @brief handling of tickless idle when interrupted
*
* The routine, called by _SysPowerSaveIdleExit, is responsible for taking the
* timer out of idle mode and generating an interrupt at the next tick
* interval. It is expected that interrupts have been disabled.
*
* RETURNS: N/A
*/
void z_clock_idle_exit(void)
{
#ifdef CONFIG_TICKLESS_KERNEL
if (!programmed_ticks && _sys_clock_always_on) {
if (!(timer0_control_register_get() & _ARC_V2_TMR_CTRL_IE)) {
timer0_control_register_set(_ARC_V2_TMR_CTRL_NH |
_ARC_V2_TMR_CTRL_IE);
}
program_max_cycles();
}
#else
if (straddled_tick_on_idle_enter) {
/* Aborting the tickless idle due to a straddled tick. */
straddled_tick_on_idle_enter = 0;
__ASSERT_EVAL({},
u32_t timer_count = timer0_count_register_get(),
timer_count <= programmed_limit,
"timer_count: %d, limit %d\n", timer_count, programmed_limit);
return;
}
u32_t control;
u32_t current_count;
current_count = timer0_count_register_get();
control = timer0_control_register_get();
if (control & _ARC_V2_TMR_CTRL_IP) {
/*
* The timer has expired. The handler _timer_int_handler() is
* guaranteed to execute. Track the number of elapsed ticks. The
* handler _timer_int_handler() will account for the final tick.
*/
_sys_idle_elapsed_ticks = programmed_ticks - 1;
update_accumulated_count();
z_clock_announce(_sys_idle_elapsed_ticks);
__ASSERT_EVAL({},
u32_t timer_count = timer0_count_register_get(),
timer_count <= programmed_limit,
"timer_count: %d, limit %d\n", timer_count, programmed_limit);
return;
}
/*
* A non-timer interrupt occurred. Announce any
* ticks that have elapsed during the tickless idle.
*/
_sys_idle_elapsed_ticks = current_count / cycles_per_tick;
if (_sys_idle_elapsed_ticks > 0) {
update_accumulated_count();
z_clock_announce(_sys_idle_elapsed_ticks);
}
/*
* Ensure the timer will expire at the end of the next tick in case
* the ISR makes any threads ready to run.
*/
timer0_limit_register_set(cycles_per_tick - 1);
timer0_count_register_set(current_count % cycles_per_tick);
__ASSERT_EVAL({},
u32_t timer_count = timer0_count_register_get(),
timer_count <= (cycles_per_tick - 1),
"timer_count: %d, limit %d\n", timer_count, cycles_per_tick-1);
#endif
}
#else
static void tickless_idle_init(void) {}
#endif /* CONFIG_TICKLESS_IDLE */
/** /**
* *
@ -490,19 +164,12 @@ int z_clock_driver_init(struct device *device)
timer0_control_register_set(0); timer0_control_register_set(0);
timer0_count_register_set(0); timer0_count_register_set(0);
cycles_per_tick = sys_clock_hw_cycles_per_tick(); last_load = CYC_PER_TICK;
IRQ_CONNECT(IRQ_TIMER0, CONFIG_ARCV2_TIMER_IRQ_PRIORITY, IRQ_CONNECT(IRQ_TIMER0, CONFIG_ARCV2_TIMER_IRQ_PRIORITY,
_timer_int_handler, NULL, 0); _timer_int_handler, NULL, 0);
/* timer0_limit_register_set(last_load - 1);
* Set the reload value to achieve the configured tick rate, enable the
* counter and interrupt generation.
*/
tickless_idle_init();
timer0_limit_register_set(cycles_per_tick - 1);
timer0_control_register_set(_ARC_V2_TMR_CTRL_NH | _ARC_V2_TMR_CTRL_IE); timer0_control_register_set(_ARC_V2_TMR_CTRL_NH | _ARC_V2_TMR_CTRL_IE);
/* everything has been configured: safe to enable the interrupt */ /* everything has been configured: safe to enable the interrupt */
@ -512,76 +179,69 @@ int z_clock_driver_init(struct device *device)
return 0; return 0;
} }
#ifdef CONFIG_DEVICE_POWER_MANAGEMENT void z_clock_set_timeout(s32_t ticks, bool idle)
static int sys_clock_suspend(struct device *dev)
{ {
ARG_UNUSED(dev); /* If the kernel allows us to miss tick announcements in idle,
* then shut off
saved_limit = timer0_limit_register_get(); * the counter. (Note: we can assume if idle==true that
saved_control = timer0_control_register_get(); * interrupts are already disabled)
arcv2_timer0_device_power_state = DEVICE_PM_SUSPEND_STATE;
return 0;
}
static int sys_clock_resume(struct device *dev)
{
ARG_UNUSED(dev);
timer0_limit_register_set(saved_limit);
timer0_control_register_set(saved_control);
/*
* It is difficult to accurately know the time spent in DS.
* Expire the timer to get the scheduler called.
*/ */
timer0_count_register_set(saved_limit - 1); if (IS_ENABLED(CONFIG_TICKLESS_IDLE) && idle && ticks == K_FOREVER) {
timer0_control_register_set(0);
arcv2_timer0_device_power_state = DEVICE_PM_ACTIVE_STATE; timer0_count_register_set(0);
timer0_limit_register_set(0);
return 0; last_load = TIMER_STOPPED;
} return;
/*
* Implements the driver control management functionality
* the *context may include IN data or/and OUT data
*/
int z_clock_device_ctrl(struct device *port, u32_t ctrl_command,
void *context)
{
if (ctrl_command == DEVICE_PM_SET_POWER_STATE) {
if (*((u32_t *)context) == DEVICE_PM_SUSPEND_STATE) {
return sys_clock_suspend(port);
} else if (*((u32_t *)context) == DEVICE_PM_ACTIVE_STATE) {
return sys_clock_resume(port);
}
} else if (ctrl_command == DEVICE_PM_GET_POWER_STATE) {
*((u32_t *)context) = arcv2_timer0_device_power_state;
return 0;
} }
return 0; #if defined(CONFIG_TICKLESS_KERNEL) && !defined(CONFIG_QEMU_TICKLESS_WORKAROUND)
} u32_t delay;
#endif /* CONFIG_DEVICE_POWER_MANAGEMENT */
u32_t _timer_cycle_get_32(void) ticks = min(MAX_TICKS, max(ticks - 1, 0));
{
#ifdef CONFIG_TICKLESS_KERNEL
return (u32_t) get_elapsed_count();
#else
u32_t acc, count;
do { /* Desired delay in the future */
acc = accumulated_cycle_count; delay = (ticks == 0) ? MIN_DELAY : ticks * CYC_PER_TICK;
count = timer0_count_register_get();
} while (acc != accumulated_cycle_count);
return acc + count; k_spinlock_key_t key = k_spin_lock(&lock);
delay += elapsed();
/* Round delay up to next tick boundary */
delay = ((delay + CYC_PER_TICK - 1) / CYC_PER_TICK) * CYC_PER_TICK;
last_load = delay;
timer0_limit_register_set(last_load - 1);
timer0_control_register_set(_ARC_V2_TMR_CTRL_NH | _ARC_V2_TMR_CTRL_IE);
k_spin_unlock(&lock, key);
#endif #endif
} }
#if defined(CONFIG_SYSTEM_CLOCK_DISABLE)
u32_t z_clock_elapsed(void)
{
if (!TICKLESS) {
return 0;
}
k_spinlock_key_t key = k_spin_lock(&lock);
u32_t cyc = elapsed();
k_spin_unlock(&lock, key);
return cyc / CYC_PER_TICK;
}
u32_t _timer_cycle_get_32(void)
{
k_spinlock_key_t key = k_spin_lock(&lock);
u32_t ret = elapsed() + cycle_count;
k_spin_unlock(&lock, key);
return ret;
}
/** /**
* *
* @brief Stop announcing ticks into the kernel * @brief Stop announcing ticks into the kernel
@ -609,4 +269,3 @@ void sys_clock_disable(void)
irq_disable(ARCV2_TIMER0_INT_LVL); irq_disable(ARCV2_TIMER0_INT_LVL);
} }
#endif /* CONFIG_SYSTEM_CLOCK_DISABLE */