From e76ecd496c9b074ab21b17f12494d823a407e89a Mon Sep 17 00:00:00 2001 From: John Crispin 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 --- 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);