From patchwork Wed Jun 16 12:31:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lindgren X-Patchwork-Id: 462080 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=-13.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNWANTED_LANGUAGE_BODY, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 389EEC49EA4 for ; Wed, 16 Jun 2021 12:31:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EE52613C1 for ; Wed, 16 Jun 2021 12:31:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232620AbhFPMdg (ORCPT ); Wed, 16 Jun 2021 08:33:36 -0400 Received: from muru.com ([72.249.23.125]:46588 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232641AbhFPMde (ORCPT ); Wed, 16 Jun 2021 08:33:34 -0400 Received: from hillo.muru.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTP id C838C8125; Wed, 16 Jun 2021 12:31:36 +0000 (UTC) From: Tony Lindgren To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, Daniel Lezcano , Keerthy , Tero Kristo Subject: [Backport for 5.4.y PATCHv2 4/4] clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940 Date: Wed, 16 Jun 2021 15:31:12 +0300 Message-Id: <20210616123112.65068-4-tony@atomide.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210616123112.65068-1-tony@atomide.com> References: <20210616123112.65068-1-tony@atomide.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 25de4ce5ed02994aea8bc111d133308f6fd62566 upstream. There is a timer wrap issue on dra7 for the ARM architected timer. In a typical clock configuration the timer fails to wrap after 388 days. To work around the issue, we need to use timer-ti-dm percpu timers instead. Let's configure dmtimer3 and 4 as percpu timers by default, and warn about the issue if the dtb is not configured properly. For more information, please see the errata for "AM572x Sitara Processors Silicon Revisions 1.1, 2.0": https://www.ti.com/lit/er/sprz429m/sprz429m.pdf The concept is based on earlier reference patches done by Tero Kristo and Keerthy. Cc: Daniel Lezcano Cc: Keerthy Cc: Tero Kristo [tony@atomide.com: backported to 5.4.y] Signed-off-by: Tony Lindgren --- arch/arm/boot/dts/dra7-l4.dtsi | 4 +-- arch/arm/boot/dts/dra7.dtsi | 20 +++++++++++ arch/arm/mach-omap2/board-generic.c | 4 +-- arch/arm/mach-omap2/timer.c | 53 ++++++++++++++++++++++++++++- drivers/clk/ti/clk-7xx.c | 1 + include/linux/cpuhotplug.h | 1 + 6 files changed, 78 insertions(+), 5 deletions(-) diff --git a/arch/arm/boot/dts/dra7-l4.dtsi b/arch/arm/boot/dts/dra7-l4.dtsi --- a/arch/arm/boot/dts/dra7-l4.dtsi +++ b/arch/arm/boot/dts/dra7-l4.dtsi @@ -1176,7 +1176,7 @@ }; }; - target-module@34000 { /* 0x48034000, ap 7 46.0 */ + timer3_target: target-module@34000 { /* 0x48034000, ap 7 46.0 */ compatible = "ti,sysc-omap4-timer", "ti,sysc"; ti,hwmods = "timer3"; reg = <0x34000 0x4>, @@ -1204,7 +1204,7 @@ }; }; - target-module@36000 { /* 0x48036000, ap 9 4e.0 */ + timer4_target: target-module@36000 { /* 0x48036000, ap 9 4e.0 */ compatible = "ti,sysc-omap4-timer", "ti,sysc"; ti,hwmods = "timer4"; reg = <0x36000 0x4>, diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi --- a/arch/arm/boot/dts/dra7.dtsi +++ b/arch/arm/boot/dts/dra7.dtsi @@ -46,6 +46,7 @@ timer { compatible = "arm,armv7-timer"; + status = "disabled"; /* See ARM architected timer wrap erratum i940 */ interrupts = , , , @@ -766,3 +767,22 @@ #include "dra7-l4.dtsi" #include "dra7xx-clocks.dtsi" + +/* Local timers, see ARM architected timer wrap erratum i940 */ +&timer3_target { + ti,no-reset-on-init; + ti,no-idle; + timer@0 { + assigned-clocks = <&l4per_clkctrl DRA7_L4PER_TIMER3_CLKCTRL 24>; + assigned-clock-parents = <&timer_sys_clk_div>; + }; +}; + +&timer4_target { + ti,no-reset-on-init; + ti,no-idle; + timer@0 { + assigned-clocks = <&l4per_clkctrl DRA7_L4PER_TIMER4_CLKCTRL 24>; + assigned-clock-parents = <&timer_sys_clk_div>; + }; +}; diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c --- a/arch/arm/mach-omap2/board-generic.c +++ b/arch/arm/mach-omap2/board-generic.c @@ -327,7 +327,7 @@ DT_MACHINE_START(DRA74X_DT, "Generic DRA74X (Flattened Device Tree)") .init_late = dra7xx_init_late, .init_irq = omap_gic_of_init, .init_machine = omap_generic_init, - .init_time = omap5_realtime_timer_init, + .init_time = omap3_gptimer_timer_init, .dt_compat = dra74x_boards_compat, .restart = omap44xx_restart, MACHINE_END @@ -350,7 +350,7 @@ DT_MACHINE_START(DRA72X_DT, "Generic DRA72X (Flattened Device Tree)") .init_late = dra7xx_init_late, .init_irq = omap_gic_of_init, .init_machine = omap_generic_init, - .init_time = omap5_realtime_timer_init, + .init_time = omap3_gptimer_timer_init, .dt_compat = dra72x_boards_compat, .restart = omap44xx_restart, MACHINE_END diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c --- a/arch/arm/mach-omap2/timer.c +++ b/arch/arm/mach-omap2/timer.c @@ -42,6 +42,7 @@ #include #include #include +#include #include @@ -420,6 +421,53 @@ static void __init dmtimer_clkevt_init_common(struct dmtimer_clockevent *clkevt, timer->rate); } +static DEFINE_PER_CPU(struct dmtimer_clockevent, dmtimer_percpu_timer); + +static int omap_gptimer_starting_cpu(unsigned int cpu) +{ + struct dmtimer_clockevent *clkevt = per_cpu_ptr(&dmtimer_percpu_timer, cpu); + struct clock_event_device *dev = &clkevt->dev; + struct omap_dm_timer *timer = &clkevt->timer; + + clockevents_config_and_register(dev, timer->rate, 3, ULONG_MAX); + irq_force_affinity(dev->irq, cpumask_of(cpu)); + + return 0; +} + +static int __init dmtimer_percpu_quirk_init(void) +{ + struct dmtimer_clockevent *clkevt; + struct clock_event_device *dev; + struct device_node *arm_timer; + struct omap_dm_timer *timer; + int cpu = 0; + + arm_timer = of_find_compatible_node(NULL, NULL, "arm,armv7-timer"); + if (of_device_is_available(arm_timer)) { + pr_warn_once("ARM architected timer wrap issue i940 detected\n"); + return 0; + } + + for_each_possible_cpu(cpu) { + clkevt = per_cpu_ptr(&dmtimer_percpu_timer, cpu); + dev = &clkevt->dev; + timer = &clkevt->timer; + + dmtimer_clkevt_init_common(clkevt, 0, "timer_sys_ck", + CLOCK_EVT_FEAT_ONESHOT, + cpumask_of(cpu), + "assigned-clock-parents", + 500, "percpu timer"); + } + + cpuhp_setup_state(CPUHP_AP_OMAP_DM_TIMER_STARTING, + "clockevents/omap/gptimer:starting", + omap_gptimer_starting_cpu, NULL); + + return 0; +} + /* Clocksource code */ static struct omap_dm_timer clksrc; static bool use_gptimer_clksrc __initdata; @@ -564,6 +612,9 @@ static void __init __omap_sync32k_timer_init(int clkev_nr, const char *clkev_src 3, /* Timer internal resynch latency */ 0xffffffff); + if (soc_is_dra7xx()) + dmtimer_percpu_quirk_init(); + /* Enable the use of clocksource="gp_timer" kernel parameter */ if (use_gptimer_clksrc || gptimer) omap2_gptimer_clocksource_init(clksrc_nr, clksrc_src, @@ -591,7 +642,7 @@ void __init omap3_secure_sync32k_timer_init(void) #endif /* CONFIG_ARCH_OMAP3 */ #if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX) || \ - defined(CONFIG_SOC_AM43XX) + defined(CONFIG_SOC_AM43XX) || defined(CONFIG_SOC_DRA7XX) void __init omap3_gptimer_timer_init(void) { __omap_sync32k_timer_init(2, "timer_sys_ck", NULL, diff --git a/drivers/clk/ti/clk-7xx.c b/drivers/clk/ti/clk-7xx.c --- a/drivers/clk/ti/clk-7xx.c +++ b/drivers/clk/ti/clk-7xx.c @@ -793,6 +793,7 @@ static struct ti_dt_clk dra7xx_clks[] = { DT_CLK(NULL, "timer_32k_ck", "sys_32k_ck"), DT_CLK(NULL, "sys_clkin_ck", "timer_sys_clk_div"), DT_CLK(NULL, "sys_clkin", "sys_clkin1"), + DT_CLK(NULL, "timer_sys_ck", "timer_sys_clk_div"), DT_CLK(NULL, "atl_dpll_clk_mux", "atl-clkctrl:0000:24"), DT_CLK(NULL, "atl_gfclk_mux", "atl-clkctrl:0000:26"), DT_CLK(NULL, "dcan1_sys_clk_mux", "wkupaon-clkctrl:0068:24"), diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -119,6 +119,7 @@ enum cpuhp_state { CPUHP_AP_ARM_L2X0_STARTING, CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING, CPUHP_AP_ARM_ARCH_TIMER_STARTING, + CPUHP_AP_OMAP_DM_TIMER_STARTING, CPUHP_AP_ARM_GLOBAL_TIMER_STARTING, CPUHP_AP_JCORE_TIMER_STARTING, CPUHP_AP_ARM_TWD_STARTING,