From patchwork Thu Jun 21 08:15:04 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "J, KEERTHY" X-Patchwork-Id: 10479427 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id CC1F7604D3 for ; Thu, 21 Jun 2018 08:16:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BFA9F28E38 for ; Thu, 21 Jun 2018 08:16:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B40D428FC1; Thu, 21 Jun 2018 08:16:11 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4CE4628E38 for ; Thu, 21 Jun 2018 08:16:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932718AbeFUIPc (ORCPT ); Thu, 21 Jun 2018 04:15:32 -0400 Received: from lelnx194.ext.ti.com ([198.47.27.80]:56983 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932466AbeFUIP3 (ORCPT ); Thu, 21 Jun 2018 04:15:29 -0400 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by lelnx194.ext.ti.com (8.15.1/8.15.1) with ESMTP id w5L8FNZ4006847; Thu, 21 Jun 2018 03:15:23 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1529568923; bh=7+dBmx3ZNMF0bWiqpFdFHnq4km/4emHSVO4TaLZl1GU=; h=From:To:CC:Subject:Date:In-Reply-To:References; b=ph1nKB12QzDiikb5RRr8raxpGJStZEh81Vba8OFzdrBQ/WmuEqyFxeOhhZGARIYQE S3pgKOo5QguciYRS0cCq31vFGdprUISfTSRPmGaqzehEfIJEssKiAO+dP+Eih61P/m mtuvPdj9AYr2SRgSaepK9WoqNddjmSFU0i1N14oU= Received: from DFLE104.ent.ti.com (dfle104.ent.ti.com [10.64.6.25]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id w5L8FNBC006722; Thu, 21 Jun 2018 03:15:23 -0500 Received: from DFLE109.ent.ti.com (10.64.6.30) by DFLE104.ent.ti.com (10.64.6.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1466.3; Thu, 21 Jun 2018 03:15:22 -0500 Received: from dflp32.itg.ti.com (10.64.6.15) by DFLE109.ent.ti.com (10.64.6.30) with Microsoft SMTP Server (version=TLS1_0, cipher=TLS_RSA_WITH_AES_256_CBC_SHA) id 15.1.1466.3 via Frontend Transport; Thu, 21 Jun 2018 03:15:22 -0500 Received: from ula0393675.india.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dflp32.itg.ti.com (8.14.3/8.13.8) with ESMTP id w5L8FCTe025379; Thu, 21 Jun 2018 03:15:20 -0500 From: Keerthy To: , , CC: , , , , , Russ Dill Subject: [PATCH v3 1/4] clk: clk: Add functions to save/restore clock context en-masse Date: Thu, 21 Jun 2018 13:45:04 +0530 Message-ID: <1529568907-19930-2-git-send-email-j-keerthy@ti.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1529568907-19930-1-git-send-email-j-keerthy@ti.com> References: <1529568907-19930-1-git-send-email-j-keerthy@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Russ Dill Deep enough power saving mode can result into losing context of the clock registers also, and they need to be restored once coming back from the power saving mode. Hence add functions to save/restore clock context. Signed-off-by: Keerthy Signed-off-by: Russ Dill --- No Changes in v2 drivers/clk/clk.c | 74 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/clk-provider.h | 7 +++++ include/linux/clk.h | 25 +++++++++++++++ 3 files changed, 106 insertions(+) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index a24a6af..7347e06 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -910,6 +910,80 @@ static int clk_core_enable_lock(struct clk_core *core) return ret; } +static int _clk_save_context(struct clk_core *clk) +{ + struct clk_core *child; + int ret = 0; + + hlist_for_each_entry(child, &clk->children, child_node) { + ret = _clk_save_context(child); + if (ret < 0) + return ret; + } + + if (clk->ops && clk->ops->save_context) + ret = clk->ops->save_context(clk->hw); + + return ret; +} + +static void _clk_restore_context(struct clk_core *clk) +{ + struct clk_core *child; + + if (clk->ops && clk->ops->restore_context) + clk->ops->restore_context(clk->hw); + + hlist_for_each_entry(child, &clk->children, child_node) + _clk_restore_context(child); +} + +/** + * clk_save_context - save clock context for poweroff + * + * Saves the context of the clock register for powerstates in which the + * contents of the registers will be lost. Occurs deep within the suspend + * code. Returns 0 on success. + */ +int clk_save_context(void) +{ + struct clk_core *clk; + int ret; + + hlist_for_each_entry(clk, &clk_root_list, child_node) { + ret = _clk_save_context(clk); + if (ret < 0) + return ret; + } + + hlist_for_each_entry(clk, &clk_orphan_list, child_node) { + ret = _clk_save_context(clk); + if (ret < 0) + return ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(clk_save_context); + +/** + * clk_restore_context - restore clock context after poweroff + * + * Restore the saved clock context upon resume. + * + */ +void clk_restore_context(void) +{ + struct clk_core *clk; + + hlist_for_each_entry(clk, &clk_root_list, child_node) + _clk_restore_context(clk); + + hlist_for_each_entry(clk, &clk_orphan_list, child_node) + _clk_restore_context(clk); +} +EXPORT_SYMBOL_GPL(clk_restore_context); + /** * clk_enable - ungate a clock * @clk: the clk being ungated diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index b7cfa03..7f30d62 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -106,6 +106,11 @@ struct clk_rate_request { * Called with enable_lock held. This function must not * sleep. * + * @save_context: Save the context of the clock in prepration for poweroff. + * + * @restore_context: Restore the context of the clock after a restoration + * of power. + * * @recalc_rate Recalculate the rate of this clock, by querying hardware. The * parent rate is an input parameter. It is up to the caller to * ensure that the prepare_mutex is held across this call. @@ -201,6 +206,8 @@ struct clk_ops { void (*disable)(struct clk_hw *hw); int (*is_enabled)(struct clk_hw *hw); void (*disable_unused)(struct clk_hw *hw); + int (*save_context)(struct clk_hw *hw); + void (*restore_context)(struct clk_hw *hw); unsigned long (*recalc_rate)(struct clk_hw *hw, unsigned long parent_rate); long (*round_rate)(struct clk_hw *hw, unsigned long rate, diff --git a/include/linux/clk.h b/include/linux/clk.h index 0dbd088..70a2662 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -596,6 +596,23 @@ int __must_check clk_bulk_enable(int num_clks, */ struct clk *clk_get_sys(const char *dev_id, const char *con_id); +/** + * clk_save_context - save clock context for poweroff + * + * Saves the context of the clock register for powerstates in which the + * contents of the registers will be lost. Occurs deep within the suspend + * code so locking is not necessary. + */ +int clk_save_context(void); + +/** + * clk_restore_context - restore clock context after poweroff + * + * This occurs with all clocks enabled. Occurs deep within the resume code + * so locking is not necessary. + */ +void clk_restore_context(void); + #else /* !CONFIG_HAVE_CLK */ static inline struct clk *clk_get(struct device *dev, const char *id) @@ -695,6 +712,14 @@ static inline struct clk *clk_get_sys(const char *dev_id, const char *con_id) { return NULL; } + +static inline int clk_save_context(void) +{ + return 0; +} + +static inline void clk_restore_context(void) {} + #endif /* clk_prepare_enable helps cases using clk_enable in non-atomic context. */