In order to prepare the clocksource code, let's encapsulate the clockevent code, split the prescaler and timer width code into separate functions.
Signed-off-by: Daniel Lezcano <[email protected]> --- drivers/clocksource/timer-stm32.c | 107 +++++++++++++++++++++++++++++--------- 1 file changed, 82 insertions(+), 25 deletions(-) diff --git a/drivers/clocksource/timer-stm32.c b/drivers/clocksource/timer-stm32.c index baca42c..1891924 100644 --- a/drivers/clocksource/timer-stm32.c +++ b/drivers/clocksource/timer-stm32.c @@ -44,6 +44,42 @@ #define TIM_PSC_MAX USHRT_MAX #define TIM_PSC_CLKRATE 10000 +struct stm32_timer_private { + int bits; +}; + +/** + * stm32_timer_of_bits_set - set accessor helper + * @to: a timer_of structure pointer + * @bits: the number of bits (16 or 32) + * + * Accessor helper to set the number of bits in the timer-of private + * structure. + * + */ +static void stm32_timer_of_bits_set(struct timer_of *to, int bits) +{ + struct stm32_timer_private *pd = to->private_data; + + pd->bits = bits; +} + +/** + * stm32_timer_of_bits_get - get accessor helper + * @to: a timer_of structure pointer + * + * Accessor helper to get the number of bits in the timer-of private + * structure. + * + * Returns an integer corresponding to the number of bits. + */ +static int stm32_timer_of_bits_get(struct timer_of *to) +{ + struct stm32_timer_private *pd = to->private_data; + + return pd->bits; +} + static void stm32_clock_event_disable(struct timer_of *to) { writel_relaxed(0, timer_of_base(to) + TIM_DIER); @@ -124,35 +160,31 @@ static irqreturn_t stm32_clock_event_handler(int irq, void *dev_id) * is a 32bits width, the result will be UINT_MAX, otherwise it will * be truncated by the 16bits register to USHRT_MAX. * - * Returns UINT_MAX if the timer is 32bits width, USHRT_MAX if it is a - * 16bits width. */ -static u32 __init stm32_timer_width(struct timer_of *to) +static void __init stm32_timer_set_width(struct timer_of *to) { + u32 width; + writel_relaxed(UINT_MAX, timer_of_base(to) + TIM_ARR); - return readl_relaxed(timer_of_base(to) + TIM_ARR); + width = readl_relaxed(timer_of_base(to) + TIM_ARR); + + stm32_timer_of_bits_set(to, width == UINT_MAX ? 32 : 16); } -static void __init stm32_clockevent_init(struct timer_of *to) +/** + * stm32_timer_set_prescaler - Compute and set the prescaler register + * @to: a pointer to a timer-of structure + * + * Depending on the timer width, compute the prescaler to always + * target a 10MHz timer rate for the 16bits. 32bits timers are + * considered precise and long enough to not use the prescaler. + */ +static void __init stm32_timer_set_prescaler(struct timer_of *to) { - u32 width = 0; - int prescaler; + int prescaler = 1; - to->clkevt.name = to->np->full_name; - to->clkevt.features = CLOCK_EVT_FEAT_PERIODIC; - to->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; - to->clkevt.set_state_shutdown = stm32_clock_event_shutdown; - to->clkevt.set_state_periodic = stm32_clock_event_set_periodic; - to->clkevt.set_state_oneshot = stm32_clock_event_set_oneshot; - to->clkevt.tick_resume = stm32_clock_event_shutdown; - to->clkevt.set_next_event = stm32_clock_event_set_next_event; - - width = stm32_timer_width(to); - if (width == UINT_MAX) { - prescaler = 1; - to->clkevt.rating = 250; - } else { + if (stm32_timer_of_bits_get(to) != 32) { prescaler = DIV_ROUND_CLOSEST(timer_of_rate(to), TIM_PSC_CLKRATE); /* @@ -161,7 +193,6 @@ static void __init stm32_clockevent_init(struct timer_of *to) * this case. */ prescaler = prescaler < TIM_PSC_MAX ? prescaler : TIM_PSC_MAX; - to->clkevt.rating = 100; } writel_relaxed(prescaler - 1, timer_of_base(to) + TIM_PSC); @@ -171,12 +202,26 @@ static void __init stm32_clockevent_init(struct timer_of *to) /* Adjust rate and period given the prescaler value */ to->of_clk.rate = DIV_ROUND_CLOSEST(to->of_clk.rate, prescaler); to->of_clk.period = DIV_ROUND_UP(to->of_clk.rate, HZ); +} + +static void __init stm32_clockevent_init(struct timer_of *to) +{ + u32 bits = stm32_timer_of_bits_get(to); - clockevents_config_and_register(&to->clkevt, - timer_of_rate(to), 0x1, width); + to->clkevt.name = to->np->full_name; + to->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; + to->clkevt.set_state_shutdown = stm32_clock_event_shutdown; + to->clkevt.set_state_periodic = stm32_clock_event_set_periodic; + to->clkevt.set_state_oneshot = stm32_clock_event_set_oneshot; + to->clkevt.tick_resume = stm32_clock_event_shutdown; + to->clkevt.set_next_event = stm32_clock_event_set_next_event; + to->clkevt.rating = bits == 32 ? 250 : 100; + + clockevents_config_and_register(&to->clkevt, timer_of_rate(to), 0x1, + (1 << bits) - 1); pr_info("%pOF: STM32 clockevent driver initialized (%d bits)\n", - to->np, width == UINT_MAX ? 32 : 16); + to->np, bits); } static int __init stm32_timer_init(struct device_node *node) @@ -196,14 +241,26 @@ static int __init stm32_timer_init(struct device_node *node) if (ret) goto err; + to->private_data = kzalloc(sizeof(struct stm32_timer_private), + GFP_KERNEL); + if (!to->private_data) + goto deinit; + rstc = of_reset_control_get(node, NULL); if (!IS_ERR(rstc)) { reset_control_assert(rstc); reset_control_deassert(rstc); } + stm32_timer_set_width(to); + + stm32_timer_set_prescaler(to); + stm32_clockevent_init(to); return 0; + +deinit: + timer_of_cleanup(to); err: kfree(to); return ret; -- 2.7.4
