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Message-ID: <56EADDED.3020606@linaro.org>
Date: Thu, 17 Mar 2016 17:40:13 +0100
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: Neil Armstrong <narmstrong@...libre.com>,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
tglx@...utronix.de, rmk+kernel@....linux.org.uk,
sudeep.holla@....com
Subject: Re: [PATCH v2 01/18] clocksource: sp804: Add support for non-32bit
width counter
On 03/09/2016 11:24 AM, Neil Armstrong wrote:
> Some vendor variants can implement norrower counter width, add
> an optional DT property changing the clocksource width and the
> clockevent mask, but keeping 32bit as default for legacy interface.
>
> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
> ---
> drivers/clocksource/timer-sp804.c | 38 +++++++++++++++++++++++++++-----------
> include/clocksource/timer-sp804.h | 11 ++++++-----
> 2 files changed, 33 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/clocksource/timer-sp804.c b/drivers/clocksource/timer-sp804.c
> index 5f45b9a..8acf524 100644
> --- a/drivers/clocksource/timer-sp804.c
> +++ b/drivers/clocksource/timer-sp804.c
> @@ -80,7 +80,8 @@ void __init sp804_timer_disable(void __iomem *base)
> void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
> const char *name,
> struct clk *clk,
> - int use_sched_clock)
> + int use_sched_clock,
> + unsigned width)
> {
> long rate;
>
> @@ -93,6 +94,9 @@ void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
> }
> }
>
> + if (!width || width > 32)
> + width = 32;
> +
check comment below in the caller function.
> rate = sp804_get_clock_rate(clk);
>
> if (rate < 0)
> @@ -106,11 +110,11 @@ void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
> base + TIMER_CTRL);
>
> clocksource_mmio_init(base + TIMER_VALUE, name,
> - rate, 200, 32, clocksource_mmio_readl_down);
> + rate, 200, width, clocksource_mmio_readl_down);
>
> if (use_sched_clock) {
> sched_clock_base = base;
> - sched_clock_register(sp804_read, 32, rate);
> + sched_clock_register(sp804_read, width, rate);
> }
> }
>
> @@ -186,7 +190,9 @@ static struct irqaction sp804_timer_irq = {
> .dev_id = &sp804_clockevent,
> };
>
> -void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struct clk *clk, const char *name)
> +void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq,
> + struct clk *clk, const char *name,
> + unsigned width)
> {
> struct clock_event_device *evt = &sp804_clockevent;
> long rate;
> @@ -199,6 +205,9 @@ void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struc
> return;
> }
>
> + if (!width || width > 32)
> + width = 32;
Check comment below in the caller function.
> rate = sp804_get_clock_rate(clk);
> if (rate < 0)
> return;
> @@ -212,7 +221,7 @@ void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struc
> writel(0, base + TIMER_CTRL);
>
> setup_irq(irq, &sp804_timer_irq);
> - clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
> + clockevents_config_and_register(evt, rate, 0xf, GENMASK(width-1, 0));
This GENMASK is strange here. Nothing else than this ?
> }
>
> static void __init sp804_of_init(struct device_node *np)
> @@ -223,6 +232,7 @@ static void __init sp804_of_init(struct device_node *np)
> u32 irq_num = 0;
> struct clk *clk1, *clk2;
> const char *name = of_get_property(np, "compatible", NULL);
> + u32 width = 32;
>
> base = of_iomap(np, 0);
> if (WARN_ON(!base))
> @@ -254,14 +264,19 @@ static void __init sp804_of_init(struct device_node *np)
> if (irq <= 0)
> goto err;
>
> + /* Some vendor variants can have a different counter width */
> + of_property_read_u32(np, "arm,timer-width", &width);
> +
Better to do the sanity check when the value is read.
Here, you can default to 32 if the width is 0 instead of initializing to
32 then read the property and call __sp804_clockevents_init which in
turn check zero or more and set it to 32 again.
> of_property_read_u32(np, "arm,sp804-has-irq", &irq_num);
> if (irq_num == 2) {
> - __sp804_clockevents_init(base + TIMER_2_BASE, irq, clk2, name);
> - __sp804_clocksource_and_sched_clock_init(base, name, clk1, 1);
> + __sp804_clockevents_init(base + TIMER_2_BASE, irq,
> + clk2, name, width);
> + __sp804_clocksource_and_sched_clock_init(base, name,
> + clk1, 1, width);
> } else {
> - __sp804_clockevents_init(base, irq, clk1 , name);
> + __sp804_clockevents_init(base, irq, clk1, name, width);
> __sp804_clocksource_and_sched_clock_init(base + TIMER_2_BASE,
> - name, clk2, 1);
> + name, clk2, 1, width);
> }
> initialized = true;
>
> @@ -293,13 +308,14 @@ static void __init integrator_cp_of_init(struct device_node *np)
> goto err;
>
> if (!init_count)
> - __sp804_clocksource_and_sched_clock_init(base, name, clk, 0);
> + __sp804_clocksource_and_sched_clock_init(base, name,
> + clk, 0, 32);
> else {
> irq = irq_of_parse_and_map(np, 0);
> if (irq <= 0)
> goto err;
>
> - __sp804_clockevents_init(base, irq, clk, name);
> + __sp804_clockevents_init(base, irq, clk, name, 32);
> }
>
> init_count++;
> diff --git a/include/clocksource/timer-sp804.h b/include/clocksource/timer-sp804.h
> index 1f8a1ca..ad71fcb 100644
> --- a/include/clocksource/timer-sp804.h
> +++ b/include/clocksource/timer-sp804.h
> @@ -4,25 +4,26 @@
> struct clk;
>
> void __sp804_clocksource_and_sched_clock_init(void __iomem *,
> - const char *, struct clk *, int);
> + const char *, struct clk *,
> + int, unsigned);
> void __sp804_clockevents_init(void __iomem *, unsigned int,
> - struct clk *, const char *);
> + struct clk *, const char *, unsigned);
> void sp804_timer_disable(void __iomem *);
>
> static inline void sp804_clocksource_init(void __iomem *base, const char *name)
> {
> - __sp804_clocksource_and_sched_clock_init(base, name, NULL, 0);
> + __sp804_clocksource_and_sched_clock_init(base, name, NULL, 0, 32);
> }
>
> static inline void sp804_clocksource_and_sched_clock_init(void __iomem *base,
> const char *name)
> {
> - __sp804_clocksource_and_sched_clock_init(base, name, NULL, 1);
> + __sp804_clocksource_and_sched_clock_init(base, name, NULL, 1, 32);
> }
>
> static inline void sp804_clockevents_init(void __iomem *base, unsigned int irq, const char *name)
> {
> - __sp804_clockevents_init(base, irq, NULL, name);
> + __sp804_clockevents_init(base, irq, NULL, name, 32);
>
> }
> #endif
>
--
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