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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/mips/loongson64/hpet.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | arch/mips/loongson64/hpet.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/arch/mips/loongson64/hpet.c b/arch/mips/loongson64/hpet.c new file mode 100644 index 000000000..e42825925 --- /dev/null +++ b/arch/mips/loongson64/hpet.c @@ -0,0 +1,285 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/init.h> +#include <linux/pci.h> +#include <linux/percpu.h> +#include <linux/delay.h> +#include <linux/spinlock.h> +#include <linux/interrupt.h> + +#include <asm/hpet.h> +#include <asm/time.h> + +#define SMBUS_CFG_BASE (loongson_sysconf.ht_control_base + 0x0300a000) +#define SMBUS_PCI_REG40 0x40 +#define SMBUS_PCI_REG64 0x64 +#define SMBUS_PCI_REGB4 0xb4 + +#define HPET_MIN_CYCLES 16 +#define HPET_MIN_PROG_DELTA (HPET_MIN_CYCLES * 12) + +static DEFINE_SPINLOCK(hpet_lock); +DEFINE_PER_CPU(struct clock_event_device, hpet_clockevent_device); + +static unsigned int smbus_read(int offset) +{ + return *(volatile unsigned int *)(SMBUS_CFG_BASE + offset); +} + +static void smbus_write(int offset, int data) +{ + *(volatile unsigned int *)(SMBUS_CFG_BASE + offset) = data; +} + +static void smbus_enable(int offset, int bit) +{ + unsigned int cfg = smbus_read(offset); + + cfg |= bit; + smbus_write(offset, cfg); +} + +static int hpet_read(int offset) +{ + return *(volatile unsigned int *)(HPET_MMIO_ADDR + offset); +} + +static void hpet_write(int offset, int data) +{ + *(volatile unsigned int *)(HPET_MMIO_ADDR + offset) = data; +} + +static void hpet_start_counter(void) +{ + unsigned int cfg = hpet_read(HPET_CFG); + + cfg |= HPET_CFG_ENABLE; + hpet_write(HPET_CFG, cfg); +} + +static void hpet_stop_counter(void) +{ + unsigned int cfg = hpet_read(HPET_CFG); + + cfg &= ~HPET_CFG_ENABLE; + hpet_write(HPET_CFG, cfg); +} + +static void hpet_reset_counter(void) +{ + hpet_write(HPET_COUNTER, 0); + hpet_write(HPET_COUNTER + 4, 0); +} + +static void hpet_restart_counter(void) +{ + hpet_stop_counter(); + hpet_reset_counter(); + hpet_start_counter(); +} + +static void hpet_enable_legacy_int(void) +{ + /* Do nothing on Loongson-3 */ +} + +static int hpet_set_state_periodic(struct clock_event_device *evt) +{ + int cfg; + + spin_lock(&hpet_lock); + + pr_info("set clock event to periodic mode!\n"); + /* stop counter */ + hpet_stop_counter(); + + /* enables the timer0 to generate a periodic interrupt */ + cfg = hpet_read(HPET_T0_CFG); + cfg &= ~HPET_TN_LEVEL; + cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL | + HPET_TN_32BIT; + hpet_write(HPET_T0_CFG, cfg); + + /* set the comparator */ + hpet_write(HPET_T0_CMP, HPET_COMPARE_VAL); + udelay(1); + hpet_write(HPET_T0_CMP, HPET_COMPARE_VAL); + + /* start counter */ + hpet_start_counter(); + + spin_unlock(&hpet_lock); + return 0; +} + +static int hpet_set_state_shutdown(struct clock_event_device *evt) +{ + int cfg; + + spin_lock(&hpet_lock); + + cfg = hpet_read(HPET_T0_CFG); + cfg &= ~HPET_TN_ENABLE; + hpet_write(HPET_T0_CFG, cfg); + + spin_unlock(&hpet_lock); + return 0; +} + +static int hpet_set_state_oneshot(struct clock_event_device *evt) +{ + int cfg; + + spin_lock(&hpet_lock); + + pr_info("set clock event to one shot mode!\n"); + cfg = hpet_read(HPET_T0_CFG); + /* + * set timer0 type + * 1 : periodic interrupt + * 0 : non-periodic(oneshot) interrupt + */ + cfg &= ~HPET_TN_PERIODIC; + cfg |= HPET_TN_ENABLE | HPET_TN_32BIT; + hpet_write(HPET_T0_CFG, cfg); + + spin_unlock(&hpet_lock); + return 0; +} + +static int hpet_tick_resume(struct clock_event_device *evt) +{ + spin_lock(&hpet_lock); + hpet_enable_legacy_int(); + spin_unlock(&hpet_lock); + + return 0; +} + +static int hpet_next_event(unsigned long delta, + struct clock_event_device *evt) +{ + u32 cnt; + s32 res; + + cnt = hpet_read(HPET_COUNTER); + cnt += (u32) delta; + hpet_write(HPET_T0_CMP, cnt); + + res = (s32)(cnt - hpet_read(HPET_COUNTER)); + + return res < HPET_MIN_CYCLES ? -ETIME : 0; +} + +static irqreturn_t hpet_irq_handler(int irq, void *data) +{ + int is_irq; + struct clock_event_device *cd; + unsigned int cpu = smp_processor_id(); + + is_irq = hpet_read(HPET_STATUS); + if (is_irq & HPET_T0_IRS) { + /* clear the TIMER0 irq status register */ + hpet_write(HPET_STATUS, HPET_T0_IRS); + cd = &per_cpu(hpet_clockevent_device, cpu); + cd->event_handler(cd); + return IRQ_HANDLED; + } + return IRQ_NONE; +} + +/* + * hpet address assignation and irq setting should be done in bios. + * but pmon don't do this, we just setup here directly. + * The operation under is normal. unfortunately, hpet_setup process + * is before pci initialize. + * + * { + * struct pci_dev *pdev; + * + * pdev = pci_get_device(PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS, NULL); + * pci_write_config_word(pdev, SMBUS_PCI_REGB4, HPET_ADDR); + * + * ... + * } + */ +static void hpet_setup(void) +{ + /* set hpet base address */ + smbus_write(SMBUS_PCI_REGB4, HPET_ADDR); + + /* enable decoding of access to HPET MMIO*/ + smbus_enable(SMBUS_PCI_REG40, (1 << 28)); + + /* HPET irq enable */ + smbus_enable(SMBUS_PCI_REG64, (1 << 10)); + + hpet_enable_legacy_int(); +} + +void __init setup_hpet_timer(void) +{ + unsigned long flags = IRQF_NOBALANCING | IRQF_TIMER; + unsigned int cpu = smp_processor_id(); + struct clock_event_device *cd; + + hpet_setup(); + + cd = &per_cpu(hpet_clockevent_device, cpu); + cd->name = "hpet"; + cd->rating = 100; + cd->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; + cd->set_state_shutdown = hpet_set_state_shutdown; + cd->set_state_periodic = hpet_set_state_periodic; + cd->set_state_oneshot = hpet_set_state_oneshot; + cd->tick_resume = hpet_tick_resume; + cd->set_next_event = hpet_next_event; + cd->irq = HPET_T0_IRQ; + cd->cpumask = cpumask_of(cpu); + clockevent_set_clock(cd, HPET_FREQ); + cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd); + cd->max_delta_ticks = 0x7fffffff; + cd->min_delta_ns = clockevent_delta2ns(HPET_MIN_PROG_DELTA, cd); + cd->min_delta_ticks = HPET_MIN_PROG_DELTA; + + clockevents_register_device(cd); + if (request_irq(HPET_T0_IRQ, hpet_irq_handler, flags, "hpet", NULL)) + pr_err("Failed to request irq %d (hpet)\n", HPET_T0_IRQ); + pr_info("hpet clock event device register\n"); +} + +static u64 hpet_read_counter(struct clocksource *cs) +{ + return (u64)hpet_read(HPET_COUNTER); +} + +static void hpet_suspend(struct clocksource *cs) +{ +} + +static void hpet_resume(struct clocksource *cs) +{ + hpet_setup(); + hpet_restart_counter(); +} + +static struct clocksource csrc_hpet = { + .name = "hpet", + /* mips clocksource rating is less than 300, so hpet is better. */ + .rating = 300, + .read = hpet_read_counter, + .mask = CLOCKSOURCE_MASK(32), + /* oneshot mode work normal with this flag */ + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .suspend = hpet_suspend, + .resume = hpet_resume, + .mult = 0, + .shift = 10, +}; + +int __init init_hpet_clocksource(void) +{ + csrc_hpet.mult = clocksource_hz2mult(HPET_FREQ, csrc_hpet.shift); + return clocksource_register_hz(&csrc_hpet, HPET_FREQ); +} + +arch_initcall(init_hpet_clocksource); |