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drivers: timer: add LiteX timer driver

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Add LiteX timer driver with bindings for this device.

Signed-off-by: Filip Kokosinski <fkokosinski@internships.antmicro.com>
Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>
This commit is contained in:
Filip Kokosinski 2019-03-28 14:40:03 +01:00 • committed by Kumar Gala
commit c0c3cdfc57
6 changed files with 116 additions and 0 deletions
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73
drivers/timer/litex_timer.c Normal file
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/*
* Copyright (c) 2018 - 2019 Antmicro <www.antmicro.com>
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <kernel.h>
#include <arch/cpu.h>
#include <device.h>
#include <irq.h>
#include <system_timer.h>
#define TIMER_BASE DT_LITEX_TIMER0_E0002800_BASE_ADDRESS
#define TIMER_LOAD_ADDR ((TIMER_BASE) + 0x00)
#define TIMER_RELOAD_ADDR ((TIMER_BASE) + 0x10)
#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_EV 0x1
#define TIMER_IRQ DT_LITEX_TIMER0_E0002800_IRQ_0
#define TIMER_DISABLE 0x0
#define TIMER_ENABLE 0x1
#define TIMER_VALUE ((CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC) / 100)
static u32_t accumulated_cycle_count;
static void litex_timer_irq_handler(void *device)
{
ARG_UNUSED(device);
int key = irq_lock();
sys_write8(TIMER_EV, TIMER_EV_PENDING_ADDR);
accumulated_cycle_count += sys_clock_hw_cycles_per_tick();
z_clock_announce(1);
irq_unlock(key);
}
u32_t z_timer_cycle_get_32(void)
{
return accumulated_cycle_count;
}
/* tickless kernel is not supported */
u32_t z_clock_elapsed(void)
{
return 0;
}
int z_clock_driver_init(struct device *device)
{
ARG_UNUSED(device);
IRQ_CONNECT(TIMER_IRQ, DT_LITEX_TIMER0_E0002800_IRQ_0_PRIORITY,
litex_timer_irq_handler, NULL, 0);
irq_enable(TIMER_IRQ);
sys_write8(TIMER_DISABLE, TIMER_EN_ADDR);
for (int i = 0; i < 4; i++) {
sys_write8(TIMER_VALUE >> (24 - i * 8),
TIMER_RELOAD_ADDR + i * 0x4);
sys_write8(TIMER_VALUE >> (24 - i * 8),
TIMER_LOAD_ADDR + i * 0x4);
}
sys_write8(TIMER_ENABLE, TIMER_EN_ADDR);
sys_write8(sys_read8(TIMER_EV_PENDING_ADDR), TIMER_EV_PENDING_ADDR);
sys_write8(TIMER_EV, TIMER_EV_ENABLE_ADDR);
return 0;
}