Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932675AbXAWCxa (ORCPT ); Mon, 22 Jan 2007 21:53:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932694AbXAWCxa (ORCPT ); Mon, 22 Jan 2007 21:53:30 -0500 Received: from av5.karneval.cz ([81.27.192.12]:6722 "EHLO av1.karneval.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932675AbXAWCx3 (ORCPT ); Mon, 22 Jan 2007 21:53:29 -0500 From: Pavel Pisa To: Ingo Molnar Subject: Re: [PATCH query] arm: i.MX/MX1 clock event source Date: Tue, 23 Jan 2007 03:52:56 +0100 User-Agent: KMail/1.9.4 Cc: Thomas Gleixner , linux-kernel@vger.kernel.org, Sascha Hauer References: <200701210101.27345.pisa@cmp.felk.cvut.cz> <20070122195924.GD21277@elte.hu> In-Reply-To: <20070122195924.GD21277@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200701230352.57380.pisa@cmp.felk.cvut.cz> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8411 Lines: 272 On Monday 22 January 2007 20:59, Ingo Molnar wrote: > * Pavel Pisa wrote: > > Hello Thomas, Sascha and Ingo > > > > please can you find some time to review next patch > > arm: i.MX/MX1 clock event source > > which has been sent to you and to the ALKML at 2007-01-13. > > > > http://thread.gmane.org/gmane.linux.ports.arm.kernel/29510/focus=29533 > > > > There seems to be some problems, because this patch has not been > > accepted to patch-2.6.20-rc5-rt7.patch, but GENERIC_CLOCKEVENTS are > > set already for i.MX and this results in a problems to run RT kernel > > on this architecture. > > i've added your patch to -rt, but note that there's a new, slightly > incompatible clockevents code in -rt now so you'll need to do some more > (hopefully trivial) fixups for this to build and work. > > Ingo Hello Ingo, thanks for reply. I am attaching updated version of the patch at the end of e-mail. There is problem with missing include in tick-sched.c CC kernel/time/tick-sched.o /usr/src/linux-2.6.20-rc5/kernel/time/tick-sched.c: In function `tick_nohz_handler': /usr/src/linux-2.6.20-rc5/kernel/time/tick-sched.c:330: warning: implicit declaration of function `get_irq_regs' /usr/src/linux-2.6.20-rc5/kernel/time/tick-sched.c:330: warning: initialization makes pointer from integer without a cast /usr/src/linux-2.6.20-rc5/kernel/time/tick-sched.c: In function `tick_sched_timer': /usr/src/linux-2.6.20-rc5/kernel/time/tick-sched.c:425: warning: initialization makes pointer from integer without a cast LD kernel/time/built-in.o --- linux-2.6.20-rc5.orig/kernel/time/tick-sched.c +++ linux-2.6.20-rc5/kernel/time/tick-sched.c @@ -20,6 +20,7 @@ #include #include #include +#include #include "tick-internal.h" And CC arch/arm/kernel/process.o /usr/src/linux-2.6.20-rc5/arch/arm/kernel/process.c: In function `cpu_idle': /usr/src/linux-2.6.20-rc5/arch/arm/kernel/process.c:157: warning: implicit declaration of function `hrtimer_stop_sched_tick' /usr/src/linux-2.6.20-rc5/arch/arm/kernel/process.c:161: warning: implicit declaration of function `hrtimer_restart_sched_tick' --- linux-2.6.20-rc5.orig/arch/arm/kernel/process.c +++ linux-2.6.20-rc5/arch/arm/kernel/process.c @@ -154,11 +154,11 @@ void cpu_idle(void) if (!idle) idle = default_idle; leds_event(led_idle_start); - hrtimer_stop_sched_tick(); + tick_nohz_stop_sched_tick(); while (!need_resched() && !need_resched_delayed()) idle(); leds_event(led_idle_end); - hrtimer_restart_sched_tick(); + tick_nohz_restart_sched_tick(); local_irq_disable(); __preempt_enable_no_resched(); __schedule(); Unfortunately, even with these corrections boot stuck at Memory: 18972KB available (2488K code, 358K data, 92K init) I have not time now to start JTAG debugging session, so I look at that tomorrow or on Friday. It seems, that the interrupts are not coming from device. Best wishes Pavel ========================================================================== Subject: arm: i.MX/MX1 clock event source Support clock event source based on i.MX general purpose timer in free running timer mode. Signed-off-by: Pavel Pisa arch/arm/mach-imx/time.c | 112 ++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 107 insertions(+), 5 deletions(-) Index: linux-2.6.20-rc5/arch/arm/mach-imx/time.c =================================================================== --- linux-2.6.20-rc5.orig/arch/arm/mach-imx/time.c +++ linux-2.6.20-rc5/arch/arm/mach-imx/time.c @@ -15,6 +15,9 @@ #include #include #include +#ifdef CONFIG_GENERIC_CLOCKEVENTS +#include +#endif #include #include @@ -25,6 +28,11 @@ /* Use timer 1 as system timer */ #define TIMER_BASE IMX_TIM1_BASE +#ifdef CONFIG_GENERIC_CLOCKEVENTS +static struct clock_event_device clockevent_imx; +static enum clock_event_mode clockevent_mode = CLOCK_EVT_MODE_PERIODIC; +#endif + static unsigned long evt_diff; /* @@ -33,6 +41,7 @@ static unsigned long evt_diff; static irqreturn_t imx_timer_interrupt(int irq, void *dev_id) { + unsigned long tcmp; uint32_t tstat; /* clear the interrupt */ @@ -42,13 +51,20 @@ imx_timer_interrupt(int irq, void *dev_i if (tstat & TSTAT_COMP) { do { +#ifdef CONFIG_GENERIC_CLOCKEVENTS + if (clockevent_imx.event_handler) + clockevent_imx.event_handler(&clockevent_imx); + if (likely(clockevent_mode != CLOCK_EVT_MODE_PERIODIC)) + break; +#else write_seqlock(&xtime_lock); timer_tick(); write_sequnlock(&xtime_lock); - IMX_TCMP(TIMER_BASE) += evt_diff; +#endif + tcmp = IMX_TCMP(TIMER_BASE) + evt_diff; + IMX_TCMP(TIMER_BASE) = tcmp; - } while (unlikely((int32_t)(IMX_TCMP(TIMER_BASE) - - IMX_TCN(TIMER_BASE)) < 0)); + } while (unlikely((int32_t)(tcmp - IMX_TCN(TIMER_BASE)) < 0)); } return IRQ_HANDLED; @@ -70,7 +86,7 @@ static void __init imx_timer_hardware_in */ IMX_TCTL(TIMER_BASE) = 0; IMX_TPRER(TIMER_BASE) = 0; - IMX_TCMP(TIMER_BASE) = LATCH - 1; + IMX_TCMP(TIMER_BASE) += LATCH; IMX_TCTL(TIMER_BASE) = TCTL_FRR | TCTL_CLK_PCLK1 | TCTL_IRQEN | TCTL_TEN; evt_diff = LATCH; @@ -87,7 +103,7 @@ static struct clocksource clocksource_im .read = imx_get_cycles, .mask = 0xFFFFFFFF, .shift = 20, - .is_continuous = 1, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; static int __init imx_clocksource_init(void) @@ -99,11 +115,97 @@ static int __init imx_clocksource_init(v return 0; } +#ifdef CONFIG_GENERIC_CLOCKEVENTS + +static int imx_set_next_event(unsigned long evt, + struct clock_event_device *unused) +{ + unsigned long tcmp; + evt_diff = evt; + + tcmp = IMX_TCN(TIMER_BASE) + evt; + IMX_TCMP(TIMER_BASE) = tcmp; + + return unlikely((int32_t)(tcmp - IMX_TCN(TIMER_BASE)) < 0) ? -ETIME : 0; +} + +static void imx_set_mode(enum clock_event_mode mode, struct clock_event_device *evt) +{ + unsigned long flags; + + /* + * The timer interrupt generation is disabled at least + * for enough time to call imx_set_next_event() + */ + local_irq_save(flags); + /* Disable interrupt in GPT module */ + IMX_TCTL(TIMER_BASE) &= ~TCTL_IRQEN; + if ((mode != CLOCK_EVT_MODE_PERIODIC) || (mode != clockevent_mode)) { + /* Set event time into far-far future */ + IMX_TCMP(TIMER_BASE) = IMX_TCN(TIMER_BASE) - 3; + /* Clear pending interrupt */ + IMX_TSTAT(TIMER_BASE) &= ~TSTAT_COMP; + } + /* Remember timer mode */ + clockevent_mode = mode; + local_irq_restore(flags); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + /* It seems, that periodic mode expects old ugly latch period */ + evt_diff = LATCH; + IMX_TCMP(TIMER_BASE) = IMX_TCN(TIMER_BASE) + evt_diff; + case CLOCK_EVT_MODE_ONESHOT: + /* + * Do not put overhead of interrupt enable/disable into + * imx_set_next_event(), the core has about 4 minutes + * to call imx_set_next_event() or shutdown clock after + * mode switching + */ + local_irq_save(flags); + IMX_TCTL(TIMER_BASE) |= TCTL_IRQEN; + local_irq_restore(flags); + break; + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_UNUSED: + /* Left event sources disabled, no more interrupts appears */ + break; + } +} + +static struct clock_event_device clockevent_imx = { + .name = "imx_timer1", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .shift = 32, + .set_mode = imx_set_mode, + .set_next_event = imx_set_next_event, + .rating = 200, +}; + +static int __init imx_clockevent_init(void) +{ + clockevent_imx.mult = div_sc(imx_get_perclk1(), NSEC_PER_SEC, + clockevent_imx.shift); + clockevent_imx.max_delta_ns = + clockevent_delta2ns(0xfffffffe, &clockevent_imx); + clockevent_imx.min_delta_ns = + clockevent_delta2ns(0xf, &clockevent_imx); + clockevents_register_device(&clockevent_imx); + + return 0; +} +#endif + + static void __init imx_timer_init(void) { imx_timer_hardware_init(); imx_clocksource_init(); +#ifdef CONFIG_GENERIC_CLOCKEVENTS + imx_clockevent_init(); +#endif + /* * Make irqs happen for the system timer */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/