Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754501AbaLJD1b (ORCPT ); Tue, 9 Dec 2014 22:27:31 -0500 Received: from e8.ny.us.ibm.com ([32.97.182.138]:38962 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754331AbaLJD13 (ORCPT ); Tue, 9 Dec 2014 22:27:29 -0500 Message-ID: <5487BD8B.5060903@linux.vnet.ibm.com> Date: Wed, 10 Dec 2014 08:57:07 +0530 From: Preeti U Murthy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Kevin Hilman , Thomas Gleixner , Viresh Kumar CC: linaro-kernel@lists.linaro.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Frederic Weisbecker Subject: Re: [PATCH 1/2] clockevents: introduce ->set_dev_mode() which can return error References: <1418162614-19182-1-git-send-email-khilman@kernel.org> <1418162614-19182-2-git-send-email-khilman@kernel.org> In-Reply-To: <1418162614-19182-2-git-send-email-khilman@kernel.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14121003-0029-0000-0000-00000160D11D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/10/2014 03:33 AM, Kevin Hilman wrote: > From: Viresh Kumar > > Currently, the ->set_mode() method of a clockevent device is not > allowed to fail, so it has no return value. In order to add new > clockevent modes, and allow the setting of those modes to fail, we > need the clockevent core to be able to detect when setting a mode > fails. > > To allow detection of mode setting failures, introduce a new method > ->set_dev_mode() which can return an error if the given mode is not > supported or fails. > > Since all current modes are still not allowed to fail, the core code > simply WARNs if any modes fail. Future patches that add new mode > support will add proper error recovery based on failure conditions. > > Signed-off-by: Viresh Kumar > Reviewed-by: Kevin Hilman > [khilman: rework changelogs, minor formatting/checkpatch cleanups] > Signed-off-by: Kevin Hilman > --- > include/linux/clockchips.h | 5 ++++- > kernel/time/clockevents.c | 21 ++++++++++++++++++--- > kernel/time/timer_list.c | 5 ++++- > 3 files changed, 26 insertions(+), 5 deletions(-) > > diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h > index 2e4cb67f6e56..d969659cf688 100644 > --- a/include/linux/clockchips.h > +++ b/include/linux/clockchips.h > @@ -81,7 +81,8 @@ enum clock_event_mode { > * @mode: operating mode assigned by the management code > * @features: features > * @retries: number of forced programming retries > - * @set_mode: set mode function > + * @set_dev_mode: set dev mode function > + * @set_mode: set mode function (deprecated, use set_dev_mode instead) > * @broadcast: function to broadcast events > * @min_delta_ticks: minimum delta value in ticks stored for reconfiguration > * @max_delta_ticks: maximum delta value in ticks stored for reconfiguration > @@ -109,6 +110,8 @@ struct clock_event_device { > unsigned long retries; > > void (*broadcast)(const struct cpumask *mask); > + int (*set_dev_mode)(enum clock_event_mode mode, > + struct clock_event_device *); > void (*set_mode)(enum clock_event_mode mode, > struct clock_event_device *); > void (*suspend)(struct clock_event_device *); > diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c > index 55449909f114..f7614041240e 100644 > --- a/kernel/time/clockevents.c > +++ b/kernel/time/clockevents.c > @@ -105,7 +105,16 @@ void clockevents_set_mode(struct clock_event_device *dev, > enum clock_event_mode mode) > { > if (dev->mode != mode) { > - dev->set_mode(mode, dev); > + if (dev->set_dev_mode) { > + int ret = dev->set_dev_mode(mode, dev); > + > + /* Currently available modes shouldn't fail */ > + WARN_ONCE(ret, "Requested mode: %d, error: %d\n", > + mode, ret); > + } else { > + dev->set_mode(mode, dev); > + } > + > dev->mode = mode; > > /* > @@ -448,8 +457,14 @@ int __clockevents_update_freq(struct clock_event_device *dev, u32 freq) > if (dev->mode == CLOCK_EVT_MODE_ONESHOT) > return clockevents_program_event(dev, dev->next_event, false); > > - if (dev->mode == CLOCK_EVT_MODE_PERIODIC) > - dev->set_mode(CLOCK_EVT_MODE_PERIODIC, dev); > + if (dev->mode == CLOCK_EVT_MODE_PERIODIC) { > + /* Shouldn't fail while switching to PERIODIC MODE */ > + if (dev->set_dev_mode) > + WARN_ON_ONCE(dev->set_dev_mode(CLOCK_EVT_MODE_PERIODIC, > + dev)); > + else > + dev->set_mode(CLOCK_EVT_MODE_PERIODIC, dev); > + } > > return 0; > } > diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c > index 61ed862cdd37..957a04951ef0 100644 > --- a/kernel/time/timer_list.c > +++ b/kernel/time/timer_list.c > @@ -229,7 +229,10 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu) > SEQ_printf(m, "\n"); > > SEQ_printf(m, " set_mode: "); > - print_name_offset(m, dev->set_mode); > + if (dev->set_dev_mode) > + print_name_offset(m, dev->set_dev_mode); > + else > + print_name_offset(m, dev->set_mode); > SEQ_printf(m, "\n"); > > SEQ_printf(m, " event_handler: "); > Reviewed-by: Preeti U Murthy -- 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/