From bd30f19a006fb52bac80c6463c49dd2f4159f4ac Mon Sep 17 00:00:00 2001 From: John Crispin 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 --- arch/mips/ralink/cevt-rt3352.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/arch/mips/ralink/cevt-rt3352.c b/arch/mips/ralink/cevt-rt3352.c index a8e70a9..b36888c 100644 --- 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; @@ -36,9 +40,26 @@ 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", 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 int systick_next_event(unsigned long delta, struct clock_event_device *evt) { @@ -99,6 +120,9 @@ static int systick_shutdown(struct clock_event_device *evt) sdev->irq_requested = 0; iowrite32(0, systick.membase + SYSTICK_CONFIG); + if (systick_freq_scaling) + systick_freq_scaling(sdev, 0); + return 0; } @@ -114,15 +138,29 @@ static int systick_set_oneshot(struct clock_event_device *evt) iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN, systick.membase + SYSTICK_CONFIG); + if (systick_freq_scaling) + systick_freq_scaling(sdev, 1); + return 0; } +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); -- 1.7.10.4