[PATCH] RFT: ARM: gemini: convert to GENERIC_CLOCKEVENTS
Arnd Bergmann
arnd at arndb.de
Tue Oct 1 07:28:57 EDT 2013
On Tuesday 01 October 2013, Linus Walleij wrote:
> This converts the gemini machine to use generic clockevents
> by rewriting the timer driver.
I've put a few more people on Cc that I think have access to hardware, according
to the openwrt changelog for gemini.
It would be great if someone could test the patch before we apply it.
Arnd
> Cc: arm at kernel.org
> Cc: Hans Ulli Kroll <ulli.kroll at googlemail.com>
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
> ---
> This is flagged as Request for Testing (RFT) as I have no Gemini
> platform. If I do not get help with testing this, the next step
> will be a patch series to delete the platform.
I've suggested removing the platform before, but got the feedback that it's
actively maintained in openwrt. Unfortunately we didn't get much
activity to upstream the patches from
http://git.openwrt.org/?p=openwrt.git;a=tree;f=target/linux/gemini/patches
which are apparently required.
Rather than deleting the platform entirely, I'd be more inclined to accept
any cleanup patches like yours, testing or not, and let the downstream
users deal with fixing it up if it breaks. The ideal case of course would
be for someone to actively maintain the platform again and submit any patches
that are needed.
Arnd
> ---
> arch/arm/Kconfig | 3 +-
> arch/arm/mach-gemini/time.c | 97 +++++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 91 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 1ad6fb6..1a903e6 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -386,8 +386,9 @@ config ARCH_CLPS711X
> config ARCH_GEMINI
> bool "Cortina Systems Gemini"
> select ARCH_REQUIRE_GPIOLIB
> - select ARCH_USES_GETTIMEOFFSET
> + select CLKSRC_MMIO
> select CPU_FA526
> + select GENERIC_CLOCKEVENTS
> select NEED_MACH_GPIO_H
> help
> Support for the Cortina Systems Gemini family SoCs
> diff --git a/arch/arm/mach-gemini/time.c b/arch/arm/mach-gemini/time.c
> index 21dc5a8..0a63c4d 100644
> --- a/arch/arm/mach-gemini/time.c
> +++ b/arch/arm/mach-gemini/time.c
> @@ -13,6 +13,8 @@
> #include <mach/hardware.h>
> #include <mach/global_reg.h>
> #include <asm/mach/time.h>
> +#include <linux/clockchips.h>
> +#include <linux/clocksource.h>
>
> /*
> * Register definitions for the timers
> @@ -33,19 +35,89 @@
> #define TIMER_3_CR_CLOCK (1 << 7)
> #define TIMER_3_CR_INT (1 << 8)
>
> +static unsigned int tick_rate;
> +
> +static int gemini_timer_set_next_event(unsigned long cycles,
> + struct clock_event_device *evt)
> +{
> + u32 cr;
> +
> + cr = readl(TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
> +
> + /* This may be overdoing it, feel free to test without this */
> + cr &= ~TIMER_2_CR_ENABLE;
> + cr &= ~TIMER_2_CR_INT;
> + writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
> +
> + /* Set next event */
> + writel(cycles, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER2_BASE)));
> + writel(cycles, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER2_BASE)));
> + cr |= TIMER_2_CR_ENABLE;
> + cr |= TIMER_2_CR_INT;
> + writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
> +
> + return 0;
> +}
> +
> +static void gemini_timer_set_mode(enum clock_event_mode mode,
> + struct clock_event_device *evt)
> +{
> + u32 period = DIV_ROUND_CLOSEST(tick_rate, HZ);
> + u32 cr;
> +
> + switch (mode) {
> + case CLOCK_EVT_MODE_PERIODIC:
> + /* Start the timer */
> + writel(period,
> + TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER2_BASE)));
> + writel(period,
> + TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER2_BASE)));
> + cr = readl(TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
> + cr |= TIMER_2_CR_ENABLE;
> + cr |= TIMER_2_CR_INT;
> + writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
> + break;
> + case CLOCK_EVT_MODE_ONESHOT:
> + case CLOCK_EVT_MODE_UNUSED:
> + case CLOCK_EVT_MODE_SHUTDOWN:
> + case CLOCK_EVT_MODE_RESUME:
> + /*
> + * Disable also for oneshot: the set_next() call will
> + * arm the timer instead.
> + */
> + cr = readl(TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
> + cr &= ~TIMER_2_CR_ENABLE;
> + cr &= ~TIMER_2_CR_INT;
> + writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
> + break;
> + default:
> + break;
> + }
> +}
> +
> +/* Use TIMER2 as clock event */
> +static struct clock_event_device gemini_clockevent = {
> + .name = "TIMER2",
> + .rating = 300, /* Reasonably fast and accurate clock event */
> + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
> + .set_next_event = gemini_timer_set_next_event,
> + .set_mode = gemini_timer_set_mode,
> +};
> +
> /*
> * IRQ handler for the timer
> */
> static irqreturn_t gemini_timer_interrupt(int irq, void *dev_id)
> {
> - timer_tick();
> + struct clock_event_device *evt = &gemini_clockevent;
>
> + evt->event_handler(evt);
> return IRQ_HANDLED;
> }
>
> static struct irqaction gemini_timer_irq = {
> .name = "Gemini Timer Tick",
> - .flags = IRQF_DISABLED | IRQF_TIMER,
> + .flags = IRQF_TIMER,
> .handler = gemini_timer_interrupt,
> };
>
> @@ -54,9 +126,9 @@ static struct irqaction gemini_timer_irq = {
> */
> void __init gemini_timer_init(void)
> {
> - unsigned int tick_rate, reg_v;
> + u32 reg_v;
>
> - reg_v = __raw_readl(IO_ADDRESS(GEMINI_GLOBAL_BASE + GLOBAL_STATUS));
> + reg_v = readl(IO_ADDRESS(GEMINI_GLOBAL_BASE + GLOBAL_STATUS));
> tick_rate = REG_TO_AHB_SPEED(reg_v) * 1000000;
>
> printk(KERN_INFO "Bus: %dMHz", tick_rate / 1000000);
> @@ -82,8 +154,17 @@ void __init gemini_timer_init(void)
> * Make irqs happen for the system timer
> */
> setup_irq(IRQ_TIMER2, &gemini_timer_irq);
> - /* Start the timer */
> - __raw_writel(tick_rate / HZ, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER2_BASE)));
> - __raw_writel(tick_rate / HZ, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER2_BASE)));
> - __raw_writel(TIMER_2_CR_ENABLE | TIMER_2_CR_INT, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
> +
> + /* Enable and use TIMER1 as clock source */
> + writel(0xffffffff, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER1_BASE)));
> + writel(0xffffffff, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER1_BASE)));
> + writel(TIMER_1_CR_ENABLE, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
> + if (clocksource_mmio_init(TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER1_BASE)),
> + "TIMER1", tick_rate, 300, 32,
> + clocksource_mmio_readl_up))
> + pr_err("timer: failed to initialize gemini clock source\n");
> +
> + /* Configure and register the clockevent */
> + clockevents_config_and_register(&gemini_clockevent, tick_rate,
> + 1, 0xffffffff);
> }
> --
> 1.8.3.1
>
>
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