From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9604C54FD0 for ; Mon, 27 Apr 2020 14:31:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 993C2206CD for ; Mon, 27 Apr 2020 14:31:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727848AbgD0Obs (ORCPT ); Mon, 27 Apr 2020 10:31:48 -0400 Received: from muru.com ([72.249.23.125]:51522 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727022AbgD0Obs (ORCPT ); Mon, 27 Apr 2020 10:31:48 -0400 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id E62BE8087; Mon, 27 Apr 2020 14:32:34 +0000 (UTC) Date: Mon, 27 Apr 2020 07:31:44 -0700 From: Tony Lindgren To: Daniel Lezcano Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Keerthy , Lokesh Vutla , Tero Kristo , Thomas Gleixner , "H. Nikolaus Schaller" , Aaro Koskinen , Adam Ford , Andreas Kemnade , Michael Turquette , Stephen Boyd , devicetree@vger.kernel.org, linux-clk@vger.kernel.org, Rob Herring Subject: Re: [PATCH 02/14] clocksource/drivers/timer-ti-dm: Add clockevent and clocksource support Message-ID: <20200427143144.GQ37466@atomide.com> References: <20200417165519.4979-1-tony@atomide.com> <20200417165519.4979-3-tony@atomide.com> <62be90e2-7dbe-410d-4171-c0ad0cddc7a3@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <62be90e2-7dbe-410d-4171-c0ad0cddc7a3@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, * Daniel Lezcano [200427 09:19]: > On 17/04/2020 18:55, Tony Lindgren wrote: > > --- a/Documentation/devicetree/bindings/timer/ti,timer.txt > > +++ b/Documentation/devicetree/bindings/timer/ti,timer.txt > > @@ -14,6 +14,8 @@ Required properties: > > ti,omap5430-timer (applicable to OMAP543x devices) > > ti,am335x-timer (applicable to AM335x devices) > > ti,am335x-timer-1ms (applicable to AM335x devices) > > + ti,dmtimer-clockevent (when used as for clockevent) > > + ti,dmtimer-clocksource (when used as for clocksource) > > Please, submit a separate patch for this. > > Before you resend as is, this will be nacked as clocksource / clockevent > is not a hardware description but a Linux thing. > > Finding a way to characterize that from the DT is an endless discussion > since years, so I suggest to use a single property for the timer eg > and initialize the clocksource and the clockevent in the > driver. Hmm good point. We still need to specify which timer is a clocksource and which one a clockevent somehow. Maybe we could have a generic properties like the clock framework such as: assigned-system-clocksource assigned-system-clockevent Or do we already have something similar that can be used? > > diff --git a/drivers/clocksource/timer-ti-dm-systimer.c b/drivers/clocksource/timer-ti-dm-systimer.c > > new file mode 100644 > > --- /dev/null > > +++ b/drivers/clocksource/timer-ti-dm-systimer.c > > +struct dmtimer_clocksource { > > + struct clocksource dev; > > + struct omap_dm_timer timer; > > The usage of the timer field is to use the __omap_dm_timer_* helpers > function which does a busy looping on the status before read/write the > register. AFAICS, for the clocksource, the posted argument is zero, thus > it is possible to replace the calls to these helpers to a write / read > and perhaps the struct omap_dm_timer could be removed from the > clocksource structure. > > The driver gets obfuscated by calls to helpers which does 'posted' things. > > Why not remove those and handle the case in the driver to make it > self-encapsuled and remove the omap_dm_timer structure usage in this driver. Hmm that's a good comment indeed. If we can just use readl/writel for clockevent and clocksource driver without worrying about the posted mode flags, we can make all the old helpers static for the generic dmtimer driver. I'll take a look. > > +static int dmtimer_systimer_type2_reset(struct omap_dm_timer *timer) > > +{ > > + void __iomem *sysc = timer->io_base + OMAP_TIMER_OCP_CFG_OFFSET; > > + u32 l; > > + > > Isn't missing a write here ? Oops thanks for spotting it. Without that the mode can be whatever left over from the bootloader. > > +static int __init dmtimer_systimer_tag_disabled(struct device_node *np) > > +{ > > + struct property *prop; > > + > > + prop = kzalloc(sizeof(*prop), GFP_KERNEL); > > + if (!prop) > > + return -ENOMEM; > > + > > + prop->name = "status"; > > + prop->value = "disabled"; > > + prop->length = strlen(prop->value); > > + > > + return of_add_property(np, prop); > > Why not add this property in the DT instead ? That sounds hackish Yes that's a good point too. We need to configure the source clock anyways for the clocksource and clockevent in devicetree anyways, so setting it disabled there totally makes sense. > > + dmtimer_systimer_enable(timer); > > + dmtimer_systimer_reset(timer); > > + pr_debug("dmtimer rev %08x sysc %08x\n", readl_relaxed(timer->io_base), > > + readl_relaxed(timer->io_base + OMAP_TIMER_OCP_CFG_OFFSET)); > > + > > + if (of_find_property(np, "ti,timer-alwon", NULL)) > > + timer->capability |= OMAP_TIMER_ALWON; > > Where is used this capability in this driver ? That is just something we should show in dmesg for info as that helps to understand the board specific system timer configuration for PM related issues folks end up reporting. > > +static struct irqaction dmtimer_clockevent_irq = { > > + .name = "gp_timer", > > + .flags = IRQF_TIMER | IRQF_IRQPOLL, > > Why do you need IRQF_IRQPOLL ? I'll check if that's needed. Probably just something that has mutated into the old timer code somehow. > > + pa = of_translate_address(np, of_get_address(np, 0, NULL, NULL)); > > + pr_info("TI gptimer clockevent: %stimer@%08x at %lu Hz\n", > > + timer->capability & OMAP_TIMER_ALWON ? "always-on " : "", > > + pa, timer->rate); > > %pOF instead of of_translate_address ? That just 0 from the interconnect target module here. But doing %pOF on the np->parent should work here and for the clocksource. > > diff --git a/include/clocksource/timer-ti-dm.h b/include/clocksource/timer-ti-dm.h > > --- a/include/clocksource/timer-ti-dm.h > > +++ b/include/clocksource/timer-ti-dm.h > > @@ -97,6 +97,7 @@ struct omap_dm_timer { > > int id; > > int irq; > > struct clk *fclk; > > + struct clk *iclk; > > No need of these clocks in the structure as they are used only to > initialize. OK I'll make them local. Thanks for the review! I'll fix up the other issues you spotted too, they all seem good comments. Regards, Tony