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Message-ID: <CANLsYkyKkFZOnzQBMHUZ=_y-EfcheAfPTdUZYpPWf_EPREeO0A@mail.gmail.com>
Date: Fri, 1 Apr 2016 09:33:03 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Neil Armstrong <narmstrong@...libre.com>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
Daniel Lezcano <daniel.lezcano@...aro.org>, tglx@...utronix.de,
Russell King <rmk+kernel@....linux.org.uk>,
Sudeep Holla <sudeep.holla@....com>
Subject: Re: [PATCH 1/2] clocksource: sp804: Add support for OX810SE 24bit
timer width
On 1 April 2016 at 08:22, Neil Armstrong <narmstrong@...libre.com> wrote:
> In order to support the Dual-Timer on the Oxford Semiconductor OX810SE SoC,
> implement variable counter width, keeping 32bit as default width.
> Add new compatible string oxsemi,ox810se-rps-timer in order to select
> the 24bit counter width.
>
> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
> ---
> drivers/clocksource/timer-sp804.c | 107 ++++++++++++++++++++++++--------------
> include/clocksource/timer-sp804.h | 42 ++++++++++++---
> 2 files changed, 102 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/clocksource/timer-sp804.c b/drivers/clocksource/timer-sp804.c
> index 5f45b9a..e99269a 100644
> --- a/drivers/clocksource/timer-sp804.c
> +++ b/drivers/clocksource/timer-sp804.c
> @@ -77,15 +77,15 @@ void __init sp804_timer_disable(void __iomem *base)
> writel(0, base + TIMER_CTRL);
> }
>
> -void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
> - const char *name,
> - struct clk *clk,
> - int use_sched_clock)
> +void __init __sp804_clocksource_and_sched_clock_init(struct timer_sp804 *sp804,
> + bool use_sched_clock)
> {
> long rate;
> + u32 config = TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC;
> + struct clk *clk = sp804->clocksource_clk;
>
> if (!clk) {
> - clk = clk_get_sys("sp804", name);
> + clk = clk_get_sys("sp804", sp804->name);
> if (IS_ERR(clk)) {
> pr_err("sp804: clock not found: %d\n",
> (int)PTR_ERR(clk));
> @@ -98,19 +98,22 @@ void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
> if (rate < 0)
> return;
>
> + if (sp804->width == 32)
> + config |= TIMER_CTRL_32BIT;
> +
> /* setup timer 0 as free-running clocksource */
> - writel(0, base + TIMER_CTRL);
> - writel(0xffffffff, base + TIMER_LOAD);
> - writel(0xffffffff, base + TIMER_VALUE);
> - writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
> - base + TIMER_CTRL);
> + writel(0, sp804->clocksource_base + TIMER_CTRL);
> + writel(0xffffffff, sp804->clocksource_base + TIMER_LOAD);
> + writel(0xffffffff, sp804->clocksource_base + TIMER_VALUE);
> + writel(config, sp804->clocksource_base + TIMER_CTRL);
>
> - clocksource_mmio_init(base + TIMER_VALUE, name,
> - rate, 200, 32, clocksource_mmio_readl_down);
> + clocksource_mmio_init(sp804->clocksource_base + TIMER_VALUE,
> + sp804->name, rate, 200, sp804->width,
> + clocksource_mmio_readl_down);
>
> if (use_sched_clock) {
> - sched_clock_base = base;
> - sched_clock_register(sp804_read, 32, rate);
> + sched_clock_base = sp804->clocksource_base;
> + sched_clock_register(sp804_read, sp804->width, rate);
> }
> }
>
> @@ -186,15 +189,16 @@ 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(struct timer_sp804 *sp804)
> {
> struct clock_event_device *evt = &sp804_clockevent;
> long rate;
> + struct clk *clk = sp804->clockevent_clk;
>
> if (!clk)
> - clk = clk_get_sys("sp804", name);
> + clk = clk_get_sys("sp804", sp804->name);
> if (IS_ERR(clk)) {
> - pr_err("sp804: %s clock not found: %d\n", name,
> + pr_err("sp804: %s clock not found: %d\n", sp804->name,
> (int)PTR_ERR(clk));
> return;
> }
> @@ -203,26 +207,27 @@ void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struc
> if (rate < 0)
> return;
>
> - clkevt_base = base;
> + clkevt_base = sp804->clockevent_base;
> clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
> - evt->name = name;
> - evt->irq = irq;
> + evt->name = sp804->name;
> + evt->irq = sp804->irq;
> evt->cpumask = cpu_possible_mask;
>
> - writel(0, base + TIMER_CTRL);
> + writel(0, sp804->clockevent_base + TIMER_CTRL);
>
> - setup_irq(irq, &sp804_timer_irq);
> - clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
> + setup_irq(sp804->irq, &sp804_timer_irq);
> + clockevents_config_and_register(evt, rate, 0xf,
> + GENMASK(sp804->width-1, 0));
> }
>
> static void __init sp804_of_init(struct device_node *np)
> {
> static bool initialized = false;
> + struct timer_sp804 sp804;
> void __iomem *base;
> - int irq;
> 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))
> @@ -250,19 +255,33 @@ static void __init sp804_of_init(struct device_node *np)
> } else
> clk2 = clk1;
>
> - irq = irq_of_parse_and_map(np, 0);
> - if (irq <= 0)
> + sp804.irq = irq_of_parse_and_map(np, 0);
> + if (sp804.irq <= 0)
> goto err;
>
> + /* OX810SE Uses a special 24bit width */
> + if (of_device_is_compatible(np, "oxsemi,ox810se-rps-timer"))
> + width = 24;
Wouldn't it be better to add a new optional property for this? If the
property is not specified then we default to a width of 32. Otherwise
the new width is configured. That way we don't have to add a new
compatible string every time (however often) a special width is
encountered.
Otherwise I think the code facelift looks good,
Mathieu
> +
> 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.clockevent_base = base + TIMER_2_BASE;
> + sp804.clocksource_base = base;
> + sp804.clockevent_clk = clk2;
> + sp804.clocksource_clk = clk1;
> } else {
> - __sp804_clockevents_init(base, irq, clk1 , name);
> - __sp804_clocksource_and_sched_clock_init(base + TIMER_2_BASE,
> - name, clk2, 1);
> + sp804.clockevent_base = base;
> + sp804.clocksource_base = base + TIMER_2_BASE;
> + sp804.clockevent_clk = clk1;
> + sp804.clocksource_clk = clk2;
> }
> +
> + sp804.name = of_get_property(np, "compatible", NULL);
> + sp804.width = width;
> +
> + __sp804_clockevents_init(&sp804);
> + __sp804_clocksource_and_sched_clock_init(&sp804, true);
> +
> initialized = true;
>
> return;
> @@ -270,13 +289,13 @@ err:
> iounmap(base);
> }
> CLOCKSOURCE_OF_DECLARE(sp804, "arm,sp804", sp804_of_init);
> +CLOCKSOURCE_OF_DECLARE(ox810se, "oxsemi,ox810se-rps-timer", sp804_of_init);
>
> static void __init integrator_cp_of_init(struct device_node *np)
> {
> static int init_count = 0;
> + struct timer_sp804 sp804;
> void __iomem *base;
> - int irq;
> - const char *name = of_get_property(np, "compatible", NULL);
> struct clk *clk;
>
> base = of_iomap(np, 0);
> @@ -292,14 +311,22 @@ static void __init integrator_cp_of_init(struct device_node *np)
> if (init_count == 2 || !of_device_is_available(np))
> goto err;
>
> - if (!init_count)
> - __sp804_clocksource_and_sched_clock_init(base, name, clk, 0);
> - else {
> - irq = irq_of_parse_and_map(np, 0);
> - if (irq <= 0)
> + sp804.name = of_get_property(np, "compatible", NULL);
> + sp804.width = 32;
> +
> + if (!init_count) {
> + sp804.clocksource_base = base;
> + sp804.clocksource_clk = clk;
> +
> + __sp804_clocksource_and_sched_clock_init(&sp804, false);
> + } else {
> + sp804.clockevent_base = base;
> + sp804.clockevent_clk = clk;
> + sp804.irq = irq_of_parse_and_map(np, 0);
> + if (sp804.irq <= 0)
> goto err;
>
> - __sp804_clockevents_init(base, irq, clk, name);
> + __sp804_clockevents_init(&sp804);
> }
>
> init_count++;
> diff --git a/include/clocksource/timer-sp804.h b/include/clocksource/timer-sp804.h
> index 1f8a1ca..928091b 100644
> --- a/include/clocksource/timer-sp804.h
> +++ b/include/clocksource/timer-sp804.h
> @@ -3,26 +3,54 @@
>
> struct clk;
>
> -void __sp804_clocksource_and_sched_clock_init(void __iomem *,
> - const char *, struct clk *, int);
> -void __sp804_clockevents_init(void __iomem *, unsigned int,
> - struct clk *, const char *);
> +struct timer_sp804 {
> + void __iomem *clockevent_base;
> + void __iomem *clocksource_base;
> + const char *name;
> + struct clk *clockevent_clk;
> + struct clk *clocksource_clk;
> + unsigned int irq;
> + unsigned int width;
> +};
> +
> +void __sp804_clocksource_and_sched_clock_init(struct timer_sp804 *sp804, bool);
> +void __sp804_clockevents_init(struct timer_sp804 *sp804);
> 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);
> + struct timer_sp804 sp804 = {
> + .clocksource_base = base,
> + .name = name,
> + .clocksource_clk = NULL,
> + .width = 32,
> + };
> +
> + __sp804_clocksource_and_sched_clock_init(&sp804, false);
> }
>
> 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);
> + struct timer_sp804 sp804 = {
> + .clocksource_base = base,
> + .name = name,
> + .clocksource_clk = NULL,
> + .width = 32,
> + };
> +
> + __sp804_clocksource_and_sched_clock_init(&sp804, true);
> }
>
> static inline void sp804_clockevents_init(void __iomem *base, unsigned int irq, const char *name)
> {
> - __sp804_clockevents_init(base, irq, NULL, name);
> + struct timer_sp804 sp804 = {
> + .clockevent_base = base,
> + .name = name,
> + .clockevent_clk = NULL,
> + .width = 32,
> + };
>
> + __sp804_clockevents_init(&sp804);
> }
> #endif
> --
> 1.9.1
>
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