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drivers: litex_timer: Fix IRQ lock intolerance

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This reimplements z_timer_cycle_get_32() so it works
when IRQs are locked and solves the hung
k_busy_wait() problem.

Fixes #23622.

Signed-off-by: Jakub Cebulski <jcebulski@internships.antmicro.com>
Signed-off-by: Tomasz Gorochowik <tgorochowik@antmicro.com>
Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>

Co-authored-by: Tomasz Gorochowik <tgorochowik@antmicro.com>
This commit is contained in:
Jakub Cebulski 2020-05-18 17:32:22 +02:00 • committed by Carles Cufí
commit 265d2cfa69
1 changed files with 14 additions and 4 deletions
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18
drivers/timer/litex_timer.c
View file

@ -10,6 +10,7 @@
#include <arch/cpu.h>
#include <device.h>
#include <irq.h>
#include <spinlock.h>
#include <drivers/timer/system_timer.h>
#define TIMER_BASE DT_INST_REG_ADDR(0)
@ -18,13 +19,14 @@
#define TIMER_EN_ADDR ((TIMER_BASE) + 0x20)
#define TIMER_EV_PENDING_ADDR ((TIMER_BASE) + 0x3c)
#define TIMER_EV_ENABLE_ADDR ((TIMER_BASE) + 0x40)
#define TIMER_TOTAL_UPDATE ((TIMER_BASE) + 0x44)
#define TIMER_TOTAL ((TIMER_BASE) + 0x48)
#define TIMER_EV 0x1
#define TIMER_IRQ DT_INST_IRQN(0)
#define TIMER_DISABLE 0x0
#define TIMER_ENABLE 0x1
static u32_t accumulated_cycle_count;
#define UPDATE_TOTAL 0x1
static void litex_timer_irq_handler(void *device)
{
@ -32,7 +34,6 @@ static void litex_timer_irq_handler(void *device)
int key = irq_lock();
sys_write8(TIMER_EV, TIMER_EV_PENDING_ADDR);
accumulated_cycle_count += k_ticks_to_cyc_floor32(1);
z_clock_announce(1);
irq_unlock(key);
@ -40,7 +41,16 @@ static void litex_timer_irq_handler(void *device)
u32_t z_timer_cycle_get_32(void)
{
return accumulated_cycle_count;
static struct k_spinlock lock;
u32_t timer_total;
k_spinlock_key_t key = k_spin_lock(&lock);
litex_write8(UPDATE_TOTAL, TIMER_TOTAL_UPDATE);
timer_total = (u32_t)litex_read64(TIMER_TOTAL);
k_spin_unlock(&lock, key);
return timer_total;
}
/* tickless kernel is not supported */