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From bd30f19a006fb52bac80c6463c49dd2f4159f4ac Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Sun, 28 Jul 2013 16:26:41 +0200
Subject: [PATCH 06/53] MIPS: ralink: add cpu frequency scaling
This feature will break udelay() and cause the delay loop to have longer delays
when the frequency is scaled causing a performance hit.
Signed-off-by: John Crispin <blogic@openwrt.org>
---
arch/mips/ralink/cevt-rt3352.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
--- a/arch/mips/ralink/cevt-rt3352.c
+++ b/arch/mips/ralink/cevt-rt3352.c
@@ -29,6 +29,10 @@
/* enable the counter */
#define CFG_CNT_EN 0x1
+/* mt7620 frequency scaling defines */
+#define CLK_LUT_CFG 0x40
+#define SLEEP_EN BIT(31)
+
struct systick_device {
void __iomem *membase;
struct clock_event_device dev;
@@ -36,21 +40,53 @@ struct systick_device {
int freq_scale;
};
+static void (*systick_freq_scaling)(struct systick_device *sdev, int status);
+
static int systick_set_oneshot(struct clock_event_device *evt);
static int systick_shutdown(struct clock_event_device *evt);
+static inline void mt7620_freq_scaling(struct systick_device *sdev, int status)
+{
+ if (sdev->freq_scale == status)
+ return;
+
+ sdev->freq_scale = status;
+
+ pr_info("%s: %s autosleep mode\n", sdev->dev.name,
+ (status) ? ("enable") : ("disable"));
+ if (status)
+ rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) | SLEEP_EN, CLK_LUT_CFG);
+ else
+ rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) & ~SLEEP_EN, CLK_LUT_CFG);
+}
+
+static inline unsigned int read_count(struct systick_device *sdev)
+{
+ return ioread32(sdev->membase + SYSTICK_COUNT);
+}
+
+static inline unsigned int read_compare(struct systick_device *sdev)
+{
+ return ioread32(sdev->membase + SYSTICK_COMPARE);
+}
+
+static inline void write_compare(struct systick_device *sdev, unsigned int val)
+{
+ iowrite32(val, sdev->membase + SYSTICK_COMPARE);
+}
+
static int systick_next_event(unsigned long delta,
struct clock_event_device *evt)
{
struct systick_device *sdev;
- u32 count;
+ int res;
sdev = container_of(evt, struct systick_device, dev);
- count = ioread32(sdev->membase + SYSTICK_COUNT);
- count = (count + delta) % SYSTICK_FREQ;
- iowrite32(count, sdev->membase + SYSTICK_COMPARE);
+ delta += read_count(sdev);
+ write_compare(sdev, delta);
+ res = ((int)(read_count(sdev) - delta) >= 0) ? -ETIME : 0;
- return 0;
+ return res;
}
static void systick_event_handler(struct clock_event_device *dev)
@@ -60,20 +96,25 @@ static void systick_event_handler(struct
static irqreturn_t systick_interrupt(int irq, void *dev_id)
{
- struct clock_event_device *dev = (struct clock_event_device *) dev_id;
+ int ret = 0;
+ struct clock_event_device *cdev;
+ struct systick_device *sdev;
- dev->event_handler(dev);
+ if (read_c0_cause() & STATUSF_IP7) {
+ cdev = (struct clock_event_device *) dev_id;
+ sdev = container_of(cdev, struct systick_device, dev);
+
+ /* Clear Count/Compare Interrupt */
+ write_compare(sdev, read_compare(sdev));
+ cdev->event_handler(cdev);
+ ret = 1;
+ }
- return IRQ_HANDLED;
+ return IRQ_RETVAL(ret);
}
static struct systick_device systick = {
.dev = {
- /*
- * cevt-r4k uses 300, make sure systick
- * gets used if available
- */
- .rating = 310,
.features = CLOCK_EVT_FEAT_ONESHOT,
.set_next_event = systick_next_event,
.set_state_shutdown = systick_shutdown,
@@ -91,7 +132,13 @@ static int systick_shutdown(struct clock
if (sdev->irq_requested)
free_irq(systick.dev.irq, &systick.dev);
sdev->irq_requested = 0;
- iowrite32(0, systick.membase + SYSTICK_CONFIG);
+ iowrite32(CFG_CNT_EN, systick.membase + SYSTICK_CONFIG);
+
+ if (systick_freq_scaling)
+ systick_freq_scaling(sdev, 0);
+
+ if (systick_freq_scaling)
+ systick_freq_scaling(sdev, 1);
return 0;
}
@@ -116,33 +163,46 @@ static int systick_set_oneshot(struct cl
return 0;
}
+static const struct of_device_id systick_match[] = {
+ { .compatible = "ralink,mt7620a-systick", .data = mt7620_freq_scaling},
+ {},
+};
+
static int __init ralink_systick_init(struct device_node *np)
{
- int ret;
+ const struct of_device_id *match;
+ int rating = 200;
systick.membase = of_iomap(np, 0);
if (!systick.membase)
return -ENXIO;
- systick.dev.name = np->name;
- clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60);
- systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev);
- systick.dev.max_delta_ticks = 0x7fff;
- systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev);
- systick.dev.min_delta_ticks = 0x3;
+ match = of_match_node(systick_match, np);
+ if (match) {
+ systick_freq_scaling = match->data;
+ /*
+ * cevt-r4k uses 300, make sure systick
+ * gets used if available
+ */
+ rating = 310;
+ }
+
+ /* enable counter than register clock source */
+ iowrite32(CFG_CNT_EN, systick.membase + SYSTICK_CONFIG);
+ clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
+ SYSTICK_FREQ, rating, 16, clocksource_mmio_readl_up);
+
+ /* register clock event */
systick.dev.irq = irq_of_parse_and_map(np, 0);
if (!systick.dev.irq) {
pr_err("%pOFn: request_irq failed", np);
return -EINVAL;
}
- ret = clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
- SYSTICK_FREQ, 301, 16,
- clocksource_mmio_readl_up);
- if (ret)
- return ret;
-
- clockevents_register_device(&systick.dev);
+ systick.dev.name = np->name;
+ systick.dev.rating = rating;
+ systick.dev.cpumask = cpumask_of(0);
+ clockevents_config_and_register(&systick.dev, SYSTICK_FREQ, 0x3, 0x7fff);
pr_info("%pOFn: running - mult: %d, shift: %d\n",
np, systick.dev.mult, systick.dev.shift);
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