diff options
author | 2016-04-11 10:41:07 +0300 | |
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committer | 2016-04-13 08:17:18 +0300 | |
commit | e09b41010ba33a20a87472ee821fa407a5b8da36 (patch) | |
tree | d10dc367189862e7ca5c592f033dc3726e1df4e3 /kernel/arch/mips/loongson64/loongson-3/hpet.c | |
parent | f93b97fd65072de626c074dbe099a1fff05ce060 (diff) |
These changes are the raw update to linux-4.4.6-rt14. Kernel sources
are taken from kernel.org, and rt patch from the rt wiki download page.
During the rebasing, the following patch collided:
Force tick interrupt and get rid of softirq magic(I70131fb85).
Collisions have been removed because its logic was found on the
source already.
Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>
Diffstat (limited to 'kernel/arch/mips/loongson64/loongson-3/hpet.c')
-rw-r--r-- | kernel/arch/mips/loongson64/loongson-3/hpet.c | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/kernel/arch/mips/loongson64/loongson-3/hpet.c b/kernel/arch/mips/loongson64/loongson-3/hpet.c new file mode 100644 index 000000000..a2631a52c --- /dev/null +++ b/kernel/arch/mips/loongson64/loongson-3/hpet.c @@ -0,0 +1,286 @@ +#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 64 +#define HPET_MIN_PROG_DELTA (HPET_MIN_CYCLES + (HPET_MIN_CYCLES >> 1)) + +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) +{ + unsigned int cnt; + int res; + + cnt = hpet_read(HPET_COUNTER); + cnt += delta; + hpet_write(HPET_T0_CMP, cnt); + + res = (int)(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; +} + +static struct irqaction hpet_irq = { + .handler = hpet_irq_handler, + .flags = IRQF_NOBALANCING | IRQF_TIMER, + .name = "hpet", +}; + +/* + * 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 decodeing 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 int cpu = smp_processor_id(); + struct clock_event_device *cd; + + hpet_setup(); + + cd = &per_cpu(hpet_clockevent_device, cpu); + cd->name = "hpet"; + cd->rating = 320; + 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->min_delta_ns = clockevent_delta2ns(HPET_MIN_PROG_DELTA, cd); + + clockevents_register_device(cd); + setup_irq(HPET_T0_IRQ, &hpet_irq); + pr_info("hpet clock event device register\n"); +} + +static cycle_t hpet_read_counter(struct clocksource *cs) +{ + return (cycle_t)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); |