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(+) --- 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, @@ -95,9 +136,15 @@ static int systick_shutdown(struct clock sdev = container_of(evt, struct systick_device, dev); if (sdev->irq_requested) - free_irq(systick.dev.irq, &systick_irqaction); + remove_irq(systick.dev.irq, &systick_irqaction); 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; } @@ -117,34 +164,48 @@ 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) { + const struct of_device_id *match; + int rating = 200; int ret; systick.membase = of_iomap(np, 0); if (!systick.membase) return -ENXIO; - systick_irqaction.name = np->name; - 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("%s: request_irq failed", np->name); 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_irqaction.name = np->name; + 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("%s: running - mult: %d, shift: %d\n", np->name, systick.dev.mult, systick.dev.shift);