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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-09-08 01:01:14 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-09-08 01:01:14 -0300
commite5fd91f1ef340da553f7a79da9540c3db711c937 (patch)
treeb11842027dc6641da63f4bcc524f8678263304a3 /arch/mips/loongson64/loongson-3/hpet.c
parent2a9b0348e685a63d97486f6749622b61e9e3292f (diff)
Linux-libre 4.2-gnu
Diffstat (limited to 'arch/mips/loongson64/loongson-3/hpet.c')
-rw-r--r--arch/mips/loongson64/loongson-3/hpet.c257
1 files changed, 257 insertions, 0 deletions
diff --git a/arch/mips/loongson64/loongson-3/hpet.c b/arch/mips/loongson64/loongson-3/hpet.c
new file mode 100644
index 000000000..5c21cd3bd
--- /dev/null
+++ b/arch/mips/loongson64/loongson-3/hpet.c
@@ -0,0 +1,257 @@
+#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
+
+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 void hpet_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ int cfg = 0;
+
+ spin_lock(&hpet_lock);
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ 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();
+ break;
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_UNUSED:
+ cfg = hpet_read(HPET_T0_CFG);
+ cfg &= ~HPET_TN_ENABLE;
+ hpet_write(HPET_T0_CFG, cfg);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ 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);
+ break;
+ case CLOCK_EVT_MODE_RESUME:
+ hpet_enable_legacy_int();
+ break;
+ }
+ spin_unlock(&hpet_lock);
+}
+
+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)(hpet_read(HPET_COUNTER) - cnt) > 0) ? -ETIME : 0;
+ return res;
+}
+
+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_mode = hpet_set_mode;
+ 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 = 5000;
+
+ 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);