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- From e76ecd496c9b074ab21b17f12494d823a407e89a Mon Sep 17 00:00:00 2001
- From: John Crispin <blogic@openwrt.org>
- Date: Sun, 28 Jul 2013 16:26:41 +0200
- Subject: [PATCH 21/57] 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 | 36 ++++++++++++++++++++++++++++++++++++
- 1 file changed, 36 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;
- @@ -36,6 +40,8 @@ struct systick_device {
- int freq_scale;
- };
-
- +static void (*systick_freq_scaling)(struct systick_device *sdev, int status);
- +
- static void systick_set_clock_mode(enum clock_event_mode mode,
- struct clock_event_device *evt);
-
- @@ -87,6 +93,21 @@ static struct irqaction systick_irqactio
- .dev_id = &systick.dev,
- };
-
- +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", systick.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 void systick_set_clock_mode(enum clock_event_mode mode,
- struct clock_event_device *evt)
- {
- @@ -101,9 +122,13 @@ static void systick_set_clock_mode(enum
- sdev->irq_requested = 1;
- iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN,
- systick.membase + SYSTICK_CONFIG);
- + if (systick_freq_scaling)
- + systick_freq_scaling(sdev, 1);
- break;
-
- case CLOCK_EVT_MODE_SHUTDOWN:
- + if (systick_freq_scaling)
- + systick_freq_scaling(sdev, 0);
- if (sdev->irq_requested)
- free_irq(systick.dev.irq, &systick_irqaction);
- sdev->irq_requested = 0;
- @@ -116,12 +141,23 @@ static void systick_set_clock_mode(enum
- }
- }
-
- +static const struct of_device_id systick_match[] = {
- + { .compatible = "ralink,mt7620-systick", .data = mt7620_freq_scaling},
- + {},
- +};
- +
- static void __init ralink_systick_init(struct device_node *np)
- {
- + const struct of_device_id *match;
- +
- systick.membase = of_iomap(np, 0);
- if (!systick.membase)
- return;
-
- + match = of_match_node(systick_match, np);
- + if (match)
- + systick_freq_scaling = match->data;
- +
- systick_irqaction.name = np->name;
- systick.dev.name = np->name;
- clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60);
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