Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933544AbcKCXHD (ORCPT ); Thu, 3 Nov 2016 19:07:03 -0400 Received: from smtprelay2.synopsys.com ([198.182.60.111]:34945 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933038AbcKCXHB (ORCPT ); Thu, 3 Nov 2016 19:07:01 -0400 Subject: Re: [PATCH v2 10/10] clocksource: import ARC timer driver To: Daniel Lezcano References: <1478208701-30923-1-git-send-email-vgupta@synopsys.com> <1478208701-30923-11-git-send-email-vgupta@synopsys.com> <20161103223806.GD15759@mai> <249006fa-262e-f290-7aa1-95f8fa38b47c@synopsys.com> <20161103230146.GF15759@mai> CC: Noam Camus , , , , Newsgroups: gmane.linux.kernel,gmane.linux.kernel.arc From: Vineet Gupta Message-ID: Date: Thu, 3 Nov 2016 16:06:25 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161103230146.GF15759@mai> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.10.161.44] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2263 Lines: 63 On 11/03/2016 04:01 PM, Daniel Lezcano wrote: > On Thu, Nov 03, 2016 at 03:50:21PM -0700, Vineet Gupta wrote: >> On 11/03/2016 03:38 PM, Daniel Lezcano wrote: >>> On Thu, Nov 03, 2016 at 02:31:41PM -0700, Vineet Gupta wrote: >>>> This adds support for >>>> >>>> - CONFIG_ARC_TIMERS : legacy 32-bit TIMER0 and TIMER1 which count UP >>>> from @CNT to @LIMIT, before optionally triggering an interrupt. >>>> These are programmed using ARC auxiliary register interface. >>>> These are present in all ARC cores (ARC700 and ARC HS38) >>>> TIMER0 serves as clockevent for all ARC linux builds. >>>> TIMER1 is used for clocksource in arc700 builds. >>>> >>>> - CONFIG_ARC_TIMERS_64BIT: 64-bit counters, RTC and GFRC found in >>>> ARC HS38 cores. These are independnet IP blocks with different >>>> programming model respectively. >>>> >>>> Signed-off-by: Vineet Gupta >>>> --- >>> >>> [ ... ] >>> >>>> #include >>>> -#include >>>> >>>> #include >>>> #include >>>> @@ -263,7 +248,7 @@ static irqreturn_t timer_irq_handler(int irq, void *dev_id) >>>> * irq_set_chip_and_handler() asked for handle_percpu_devid_irq() >>>> */ >>>> struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device); >>>> - int irq_reenable = clockevent_state_periodic(evt); >>>> + int irq_reenable __maybe_unused = clockevent_state_periodic(evt); >>> >>> Why is needed __maybe_unused ? I see in the previous driver 'irq_reenable' is >>> used or is there a change in the previous patches I missed ? >> >> This is needed when not building for CONFIG_ARC (saw this when building for ARM) >> write_aux_reg() becomes a no-op which causes a warning: >> >> write_aux_reg(ARC_REG_TIMER0_CTRL, irq_reenable | TIMER_CTRL_NH); > > Instead of adding the __maybe_unused, changing in patch 7/10: > > #define read_aux_reg(r) 0 > #define write_aux_reg(r, v) > > by > > static inline int read_aux_reg(void *) > { > return 0; > } > > static inline void write_aux_reg(void *, u32) > { > ; > } > > Should fix the warning. Good point, slight mod preferred as @reg argument is not really a MMIO register so not a pointer but a number instead so I'd prefer u32 for that as well.