From patchwork Thu Apr 7 07:44:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Whitchurch X-Patchwork-Id: 558699 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3D7AC433F5 for ; Thu, 7 Apr 2022 07:44:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242070AbiDGHqo (ORCPT ); Thu, 7 Apr 2022 03:46:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242065AbiDGHqn (ORCPT ); Thu, 7 Apr 2022 03:46:43 -0400 Received: from smtp1.axis.com (smtp1.axis.com [195.60.68.17]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 979838A33E; Thu, 7 Apr 2022 00:44:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1649317484; x=1680853484; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=3Nt6l/9HvPB8EWvbnvVd3ZZ20Hk+Zo41nv15TzjFgHI=; b=eHMph5qta/o1xIqnuaph6ezehu7sttEPWYYpgy+lMENpOvJ4lf9tLx9a RLbLnWyLYYSWV5fExZ5laiJvz+BZBcURMfDmqY69inf6e+J4PQ42bbYj+ v84fX4/XalidARPQuyd79CliEpQC6qayPdsX8K8Gj0gDlszPbIY/8aD76 7EpQ29tP5T/FqMcC40nxP9Z2jySLfoKrwheqsQhVCm9wr6E7bRbuDC5Up EqhG+K165HATWNpBUuNWXWT9qN0vq5Wqfpz4kJTkRfDgA7y4eAwaZvKPa Fjtnxxr8Ibpg5A335HzmehaAK0ZDraP2ozfGJapGVoU/Cv4S6HxH4YNoj g==; From: Vincent Whitchurch To: , , CC: , Vincent Whitchurch , , , , , , Subject: [PATCH v3 2/4] clocksource/drivers/exynos_mct: Support frc-shared property Date: Thu, 7 Apr 2022 09:44:30 +0200 Message-ID: <20220407074432.424578-3-vincent.whitchurch@axis.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220407074432.424578-1-vincent.whitchurch@axis.com> References: <20220407074432.424578-1-vincent.whitchurch@axis.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org When the FRC is shared with another main processor, the other processor is assumed to have started it and this processor should not write to the global registers. Signed-off-by: Vincent Whitchurch Reviewed-by: Krzysztof Kozlowski --- Notes: v3: - Split FRC sharing handling from local timer indices handling - Remove addition of global variable. drivers/clocksource/exynos_mct.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index f29c812b70c9..12023831dedf 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -233,9 +233,16 @@ static cycles_t exynos4_read_current_timer(void) } #endif -static int __init exynos4_clocksource_init(void) +static int __init exynos4_clocksource_init(bool frc_shared) { - exynos4_mct_frc_start(); + /* + * When the frc is shared, the main processer should have already + * turned it on and we shouldn't be writing to TCON. + */ + if (frc_shared) + mct_frc.resume = NULL; + else + exynos4_mct_frc_start(); #if defined(CONFIG_ARM) exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer; @@ -605,6 +612,7 @@ static int __init exynos4_timer_interrupts(struct device_node *np, static int __init mct_init_dt(struct device_node *np, unsigned int int_type) { + bool frc_shared = of_property_read_bool(np, "samsung,frc-shared"); int ret; ret = exynos4_timer_resources(np); @@ -615,10 +623,17 @@ static int __init mct_init_dt(struct device_node *np, unsigned int int_type) if (ret) return ret; - ret = exynos4_clocksource_init(); + ret = exynos4_clocksource_init(frc_shared); if (ret) return ret; + /* + * When the FRC is shared with a main processor, this secondary + * processor cannot use the global comparator. + */ + if (frc_shared) + return ret; + return exynos4_clockevent_init(); }