From patchwork Wed Aug 12 13:54:31 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Georgi Djakov X-Patchwork-Id: 7001771 X-Patchwork-Delegate: agross@codeaurora.org Return-Path: X-Original-To: patchwork-linux-arm-msm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id E6FB6C05AC for ; Wed, 12 Aug 2015 13:55:24 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CF96F206CE for ; Wed, 12 Aug 2015 13:55:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 432F82066E for ; Wed, 12 Aug 2015 13:55:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754411AbbHLNzM (ORCPT ); Wed, 12 Aug 2015 09:55:12 -0400 Received: from mail-wi0-f174.google.com ([209.85.212.174]:37222 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752819AbbHLNzK (ORCPT ); Wed, 12 Aug 2015 09:55:10 -0400 Received: by wibhh20 with SMTP id hh20so30313971wib.0 for ; Wed, 12 Aug 2015 06:55:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=BMGNAfOvtUAkuuwcpHCkiS9n7TFpJSUkBHlQnxF4MWQ=; b=PZT58jAedm8YLSQVjCc9zLoCjEBsYQW1rWyNjgtSkrVxzDcjzjmMeIo8C13zAhp05Y nLv9mF190GWJHLvm7oJgyKQrSzuzPwazJQDleNKI6FOiOD3qDom37CRd0+OagKt5cRRg w3Q7Q/lRn/6ummbAK5Kisy60dTLrAwDuzWFVfvr5KrOZxD9Y7vlKDzgQSFIRL0vFTRMe BXbchU9WjyGknfJzUu/etwEXNWgd5+gX2Z/XSz+hq0ktB9LO9uI4aaUlIztuzz6RwGEM sgcN97HN1hhrWQdJ7JfQO3/1HvlKlIKeaVUF8x3r2CjCtWSyIHlrZggenwUOdxrbEBIG I8Ew== X-Gm-Message-State: ALoCoQmrfF3Vr8+GxfCuEI5MmA20K9cvGIVvzV2fblPdGRbW5t4j/mQp91+IF0lVeto5CM33eWN8 X-Received: by 10.194.250.69 with SMTP id za5mr67713579wjc.90.1439387709305; Wed, 12 Aug 2015 06:55:09 -0700 (PDT) Received: from mms.wifi.mm-sol.com ([37.157.136.206]) by smtp.googlemail.com with ESMTPSA id z11sm22258547wij.9.2015.08.12.06.55.07 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 Aug 2015 06:55:08 -0700 (PDT) From: Georgi Djakov To: sboyd@codeaurora.org Cc: mturquette@baylibre.com, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, georgi.djakov@linaro.org Subject: [PATCH v3 1/3] clk: Add safe switch hook Date: Wed, 12 Aug 2015 16:54:31 +0300 Message-Id: <1439387673-13015-2-git-send-email-georgi.djakov@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1439387673-13015-1-git-send-email-georgi.djakov@linaro.org> References: <1439387673-13015-1-git-send-email-georgi.djakov@linaro.org> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Stephen Boyd Sometimes clocks can't accept their parent source turning off while the source is reprogrammed to a different rate. Most notably CPU clocks require a way to switch away from the current PLL they're running on, reprogram that PLL to a new rate, and then switch back to the PLL with the new rate once they're done. Add a hook that drivers can implement allowing them to return a 'safe parent' and 'safe frequency' that they can switch their parent to while the upstream source is reprogrammed to support this. Signed-off-by: Stephen Boyd Signed-off-by: Georgi Djakov --- drivers/clk/clk.c | 73 +++++++++++++++++++++++++++++++++++++++--- include/linux/clk-provider.h | 2 ++ 2 files changed, 70 insertions(+), 5 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 128ad748b682..df5f5b65833c 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -51,9 +51,13 @@ struct clk_core { struct clk_core **parents; u8 num_parents; u8 new_parent_index; + u8 safe_parent_index; unsigned long rate; unsigned long req_rate; + unsigned long old_rate; unsigned long new_rate; + unsigned long safe_freq; + struct clk_core *safe_parent; struct clk_core *new_parent; struct clk_core *new_child; unsigned long flags; @@ -1271,7 +1275,9 @@ out: static void clk_calc_subtree(struct clk_core *core, unsigned long new_rate, struct clk_core *new_parent, u8 p_index) { - struct clk_core *child; + struct clk_core *child, *parent; + struct clk_hw *parent_hw; + unsigned long safe_freq = 0; core->new_rate = new_rate; core->new_parent = new_parent; @@ -1281,6 +1287,23 @@ static void clk_calc_subtree(struct clk_core *core, unsigned long new_rate, if (new_parent && new_parent != core->parent) new_parent->new_child = core; + if (core->ops->get_safe_parent) { + parent_hw = core->ops->get_safe_parent(core->hw, &safe_freq); + if (parent_hw) { + parent = parent_hw->core; + p_index = clk_fetch_parent_index(core, parent); + core->safe_parent_index = p_index; + core->safe_parent = parent; + if (safe_freq) + core->safe_freq = safe_freq; + else + core->safe_freq = 0; + } + } else { + core->safe_parent = NULL; + core->safe_freq = 0; + } + hlist_for_each_entry(child, &core->children, child_node) { child->new_rate = clk_recalc(child, new_rate); clk_calc_subtree(child, child->new_rate, NULL, 0); @@ -1393,14 +1416,51 @@ static struct clk_core *clk_propagate_rate_change(struct clk_core *core, unsigned long event) { struct clk_core *child, *tmp_clk, *fail_clk = NULL; + struct clk_core *old_parent; int ret = NOTIFY_DONE; - if (core->rate == core->new_rate) + if (core->rate == core->new_rate && event != POST_RATE_CHANGE) return NULL; + switch (event) { + case PRE_RATE_CHANGE: + if (core->safe_parent) { + if (core->safe_freq) + core->ops->set_rate_and_parent(core->hw, + core->safe_freq, + core->safe_parent->rate, + core->safe_parent_index); + else + core->ops->set_parent(core->hw, + core->safe_parent_index); + } + core->old_rate = core->rate; + break; + case POST_RATE_CHANGE: + if (core->safe_parent) { + old_parent = __clk_set_parent_before(core, + core->new_parent); + if (core->ops->set_rate_and_parent) { + core->ops->set_rate_and_parent(core->hw, + core->new_rate, + core->new_parent ? + core->new_parent->rate : 0, + core->new_parent_index); + } else if (core->ops->set_parent) { + core->ops->set_parent(core->hw, + core->new_parent_index); + } + __clk_set_parent_after(core, core->new_parent, + old_parent); + } + break; + } + if (core->notifier_count) { - ret = __clk_notify(core, event, core->rate, core->new_rate); - if (ret & NOTIFY_STOP_MASK) + if (event != POST_RATE_CHANGE || core->old_rate != core->rate) + ret = __clk_notify(core, event, core->old_rate, + core->new_rate); + if (ret & NOTIFY_STOP_MASK && event != POST_RATE_CHANGE) fail_clk = core; } @@ -1443,7 +1503,8 @@ static void clk_change_rate(struct clk_core *core) else if (core->parent) best_parent_rate = core->parent->rate; - if (core->new_parent && core->new_parent != core->parent) { + if (core->new_parent && core->new_parent != core->parent && + !core->safe_parent) { old_parent = __clk_set_parent_before(core, core->new_parent); trace_clk_set_parent(core, core->new_parent); @@ -1527,6 +1588,8 @@ static int clk_core_set_rate_nolock(struct clk_core *core, core->req_rate = req_rate; + clk_propagate_rate_change(top, POST_RATE_CHANGE); + return ret; } diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 0d3128fbc14e..173f681001f2 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -202,6 +202,8 @@ struct clk_ops { struct clk_rate_request *req); int (*set_parent)(struct clk_hw *hw, u8 index); u8 (*get_parent)(struct clk_hw *hw); + struct clk_hw *(*get_safe_parent)(struct clk_hw *hw, + unsigned long *safe_freq); int (*set_rate)(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate); int (*set_rate_and_parent)(struct clk_hw *hw,