diff options
Diffstat (limited to 'drivers/clocksource/arm_global_timer.c')
| -rw-r--r-- | drivers/clocksource/arm_global_timer.c | 78 |
1 files changed, 54 insertions, 24 deletions
diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c index 44a61dc6f932..5e3d6bb7e437 100644 --- a/drivers/clocksource/arm_global_timer.c +++ b/drivers/clocksource/arm_global_timer.c @@ -9,6 +9,7 @@ #include <linux/init.h> #include <linux/interrupt.h> +#include <linux/bitfield.h> #include <linux/clocksource.h> #include <linux/clockchips.h> #include <linux/cpu.h> @@ -31,10 +32,7 @@ #define GT_CONTROL_COMP_ENABLE BIT(1) /* banked */ #define GT_CONTROL_IRQ_ENABLE BIT(2) /* banked */ #define GT_CONTROL_AUTO_INC BIT(3) /* banked */ -#define GT_CONTROL_PRESCALER_SHIFT 8 -#define GT_CONTROL_PRESCALER_MAX 0xF -#define GT_CONTROL_PRESCALER_MASK (GT_CONTROL_PRESCALER_MAX << \ - GT_CONTROL_PRESCALER_SHIFT) +#define GT_CONTROL_PRESCALER_MASK GENMASK(15, 8) #define GT_INT_STATUS 0x0c #define GT_INT_STATUS_EVENT_FLAG BIT(0) @@ -52,7 +50,8 @@ */ static void __iomem *gt_base; static struct notifier_block gt_clk_rate_change_nb; -static u32 gt_psv_new, gt_psv_bck, gt_target_rate; +static u32 gt_psv_new, gt_psv_bck; +static unsigned long gt_target_rate; static int gt_ppi; static struct clock_event_device __percpu *gt_evt; @@ -88,7 +87,7 @@ static u64 gt_counter_read(void) return _gt_counter_read(); } -/** +/* * To ensure that updates to comparator value register do not set the * Interrupt Status Register proceed as follows: * 1. Clear the Comp Enable bit in the Timer Control Register. @@ -196,7 +195,6 @@ static int gt_dying_cpu(unsigned int cpu) { struct clock_event_device *clk = this_cpu_ptr(gt_evt); - gt_clockevent_shutdown(clk); disable_percpu_irq(clk->irq); return 0; } @@ -247,7 +245,7 @@ static void gt_write_presc(u32 psv) reg = readl(gt_base + GT_CONTROL); reg &= ~GT_CONTROL_PRESCALER_MASK; - reg |= psv << GT_CONTROL_PRESCALER_SHIFT; + reg |= FIELD_PREP(GT_CONTROL_PRESCALER_MASK, psv); writel(reg, gt_base + GT_CONTROL); } @@ -256,8 +254,7 @@ static u32 gt_read_presc(void) u32 reg; reg = readl(gt_base + GT_CONTROL); - reg &= GT_CONTROL_PRESCALER_MASK; - return reg >> GT_CONTROL_PRESCALER_SHIFT; + return FIELD_GET(GT_CONTROL_PRESCALER_MASK, reg); } static void __init gt_delay_timer_init(void) @@ -266,15 +263,14 @@ static void __init gt_delay_timer_init(void) register_current_timer_delay(>_delay_timer); } -static int __init gt_clocksource_init(void) +static int __init gt_clocksource_init(unsigned int psv) { writel(0, gt_base + GT_CONTROL); writel(0, gt_base + GT_COUNTER0); writel(0, gt_base + GT_COUNTER1); /* set prescaler and enable timer on all the cores */ - writel(((CONFIG_ARM_GT_INITIAL_PRESCALER_VAL - 1) << - GT_CONTROL_PRESCALER_SHIFT) - | GT_CONTROL_TIMER_ENABLE, gt_base + GT_CONTROL); + writel(FIELD_PREP(GT_CONTROL_PRESCALER_MASK, psv - 1) | + GT_CONTROL_TIMER_ENABLE, gt_base + GT_CONTROL); #ifdef CONFIG_CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK sched_clock_register(gt_sched_clock_read, 64, gt_target_rate); @@ -290,18 +286,17 @@ static int gt_clk_rate_change_cb(struct notifier_block *nb, switch (event) { case PRE_RATE_CHANGE: { - int psv; - - psv = DIV_ROUND_CLOSEST(ndata->new_rate, - gt_target_rate); + unsigned long psv; - if (abs(gt_target_rate - (ndata->new_rate / psv)) > MAX_F_ERR) + psv = DIV_ROUND_CLOSEST(ndata->new_rate, gt_target_rate); + if (!psv || + abs(gt_target_rate - (ndata->new_rate / psv)) > MAX_F_ERR) return NOTIFY_BAD; psv--; /* prescaler within legal range? */ - if (psv < 0 || psv > GT_CONTROL_PRESCALER_MAX) + if (!FIELD_FIT(GT_CONTROL_PRESCALER_MASK, psv)) return NOTIFY_BAD; /* @@ -342,11 +337,45 @@ static int gt_clk_rate_change_cb(struct notifier_block *nb, return NOTIFY_DONE; } +struct gt_prescaler_config { + const char *compatible; + unsigned long prescaler; +}; + +static const struct gt_prescaler_config gt_prescaler_configs[] = { + /* + * On am43 the global timer clock is a child of the clock used for CPU + * OPPs, so the initial prescaler has to be compatible with all OPPs + * which are 300, 600, 720, 800 and 1000 with a fixed divider of 2, this + * gives us a GCD of 10. Initial frequency is 1000, so the prescaler is + * 50. + */ + { .compatible = "ti,am43", .prescaler = 50 }, + { .compatible = "xlnx,zynq-7000", .prescaler = 2 }, + { .compatible = NULL } +}; + +static unsigned long gt_get_initial_prescaler_value(struct device_node *np) +{ + const struct gt_prescaler_config *config; + + if (CONFIG_ARM_GT_INITIAL_PRESCALER_VAL != 0) + return CONFIG_ARM_GT_INITIAL_PRESCALER_VAL; + + for (config = gt_prescaler_configs; config->compatible; config++) { + if (of_machine_is_compatible(config->compatible)) + return config->prescaler; + } + + return 1; +} + static int __init global_timer_of_register(struct device_node *np) { struct clk *gt_clk; static unsigned long gt_clk_rate; - int err = 0; + int err; + unsigned long psv; /* * In A9 r2p0 the comparators for each processor with the global timer @@ -382,8 +411,9 @@ static int __init global_timer_of_register(struct device_node *np) goto out_unmap; } + psv = gt_get_initial_prescaler_value(np); gt_clk_rate = clk_get_rate(gt_clk); - gt_target_rate = gt_clk_rate / CONFIG_ARM_GT_INITIAL_PRESCALER_VAL; + gt_target_rate = gt_clk_rate / psv; gt_clk_rate_change_nb.notifier_call = gt_clk_rate_change_cb; err = clk_notifier_register(gt_clk, >_clk_rate_change_nb); @@ -408,10 +438,10 @@ static int __init global_timer_of_register(struct device_node *np) } /* Register and immediately configure the timer on the boot CPU */ - err = gt_clocksource_init(); + err = gt_clocksource_init(psv); if (err) goto out_irq; - + err = cpuhp_setup_state(CPUHP_AP_ARM_GLOBAL_TIMER_STARTING, "clockevents/arm/global_timer:starting", gt_starting_cpu, gt_dying_cpu); |