From patchwork Sun Sep 17 22:40:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Bara X-Patchwork-Id: 724291 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2927712B80 for ; Sun, 17 Sep 2023 22:40:44 +0000 (UTC) Received: from mail-wm1-x333.google.com (mail-wm1-x333.google.com [IPv6:2a00:1450:4864:20::333]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E81912C; Sun, 17 Sep 2023 15:40:42 -0700 (PDT) Received: by mail-wm1-x333.google.com with SMTP id 5b1f17b1804b1-401b5516104so42229985e9.2; Sun, 17 Sep 2023 15:40:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1694990441; x=1695595241; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=kviONp3xwBUSyMm3n9HmjGMrxjEliGN8QJc2qo9i9Gg=; b=EDdjdIGq2P7Xcv8PTewEF6v1RKp/aAo6CdgQlXiuUxJoN1KGwOSCvXSdin+JCy8h6c khklOsRT7uUW9r/H/LKBpi9atO1TixYZUZbqw7tupfo9Y9TNg1qK9LA03g5s5cmdnhTB 7GRVNKZRVy7FU5mpYZirDWPioOpyMYi1ylagszL2Utaja+7cwNirZU3EaZQIMHyb/tko hUaO2UKcNA2gm6QqCiGCDQSBnRy0YLXzdU68ztsltiYrG6batmzBAqTcKbBkIYVZ/jd4 SsT3cN7bI8yk7y8eN/FEn4jPQrh61ekJzoYexDrZKVs/evUeAaa4CMbnV6+QXFYzmCRm nhfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694990441; x=1695595241; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=kviONp3xwBUSyMm3n9HmjGMrxjEliGN8QJc2qo9i9Gg=; b=dSBtFbhFxmgvhygqfB3Y+VjsuhnKFnxgfFTeIm3m2JuwbfcWYCMIhCzzXrAidveUCi KiH/zGOiEmCQ6SfHXgDs6oT139M1L/h0EIs/SFgRJl68IhZU6Ot3xjjkM2IAbiVO0TIv NdIN157uKdSb2FV8V/vMOkrxj4mj2N9eYhx9kLQeFyvehqjDRBHm/4ob+GEdhUktPyF3 YZ5gzF9O0wbUsp5Z72zanmId+Vmd+hkSiICLQEYEtLPYMt/o9CUC/yiOYnaBlwe6IGea gsrDDGivSFaLDbBxjeKI/hqB0NdteR5hHCIxHnRtKVZD/K69t0oqLf2wknPC1NBmSYNw B4/w== X-Gm-Message-State: AOJu0Yyy8fH5syG+MI+u7y3E/6V3G0pfo1piz2YoqLWIXIQ3YWUr8bR5 F6E1IVti8lkVm+tlnueQ1HI= X-Google-Smtp-Source: AGHT+IGI9iHWZr7kzzg0eUkNH07Lgn024wjCqs9NAjnnhsL3UBw49Jv26TH9svgPt6bxfNSbTxu3XQ== X-Received: by 2002:a1c:6a01:0:b0:401:b53e:6c3b with SMTP id f1-20020a1c6a01000000b00401b53e6c3bmr6295687wmc.6.1694990441025; Sun, 17 Sep 2023 15:40:41 -0700 (PDT) Received: from [127.0.1.1] ([91.230.2.244]) by smtp.gmail.com with ESMTPSA id x14-20020a1c7c0e000000b003fe2b081661sm13642931wmc.30.2023.09.17.15.40.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 17 Sep 2023 15:40:40 -0700 (PDT) From: Benjamin Bara Date: Mon, 18 Sep 2023 00:40:07 +0200 Subject: [PATCH 11/13] clk: imx: composite-8m: implement CLK_SET_RATE_PARENT Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20230918-imx8mp-dtsi-v1-11-1d008b3237c0@skidata.com> References: <20230918-imx8mp-dtsi-v1-0-1d008b3237c0@skidata.com> In-Reply-To: <20230918-imx8mp-dtsi-v1-0-1d008b3237c0@skidata.com> To: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Michael Turquette , Stephen Boyd , Russell King , Abel Vesa , Peng Fan Cc: Frank Oltmanns , Maxime Ripard , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, Benjamin Bara X-Mailer: b4 0.12.3 X-Spam-Status: No, score=-1.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net From: Benjamin Bara One of the key parts to enable dynamic clock propagation on the imx8m, are the consumer-facing composites. They currently only divide, therefore the parent must be already quite good in shape to provide a close enough rate. Therefore, the parents are usually hard-assigned in the dt. To workaround that, this commit enables propagation to the parent of the composite. If a rate cannot be reached exactly by only dividing, the parent is asked (for now simply for the exact required rate - no dividers taken into account). If the parent already has a configured rate, it's the parent's job to ensure that all children are satisfied. By using a notifier, the propagation-enabled clocks listen to clock changes coming from the parent. If one is happening, it's the composites job to verify if the rate is satisfying and if it is an intended change. Otherwise, countermeasures have to be taken into account (e.g. setting the rate back or aborting the change). Signed-off-by: Benjamin Bara --- drivers/clk/imx/clk-composite-8m.c | 71 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 68 insertions(+), 3 deletions(-) diff --git a/drivers/clk/imx/clk-composite-8m.c b/drivers/clk/imx/clk-composite-8m.c index a121f1285110..068f61df28b1 100644 --- a/drivers/clk/imx/clk-composite-8m.c +++ b/drivers/clk/imx/clk-composite-8m.c @@ -4,6 +4,7 @@ */ #include +#include #include #include #include @@ -119,8 +120,12 @@ static int imx8m_divider_determine_rate(struct clk_hw *hw, struct clk_rate_request *req) { struct clk_divider *divider = to_clk_divider(hw); + struct clk_hw *parent = clk_hw_get_parent(hw); int prediv_value; int div_value; + unsigned long target_rate; + struct clk_rate_request req_parent; + int ret; /* if read only, just return current value */ if (divider->flags & CLK_DIVIDER_READ_ONLY) { @@ -140,9 +145,29 @@ static int imx8m_divider_determine_rate(struct clk_hw *hw, divider->flags, prediv_value * div_value); } - return divider_determine_rate(hw, req, divider->table, - PCG_PREDIV_WIDTH + PCG_DIV_WIDTH, - divider->flags); + target_rate = req->rate; + ret = divider_determine_rate(hw, req, divider->table, + PCG_PREDIV_WIDTH + PCG_DIV_WIDTH, + divider->flags); + if (ret || req->rate == target_rate) + return ret; + + /* + * If re-configuring the parent gives a better rate, do this instead. + * Avoid re-parenting for now, which could be done first if a possible + * parent already has a satisfying rate. The implementation does not + * consider the dividers between the parent and the current clock. + */ + clk_hw_forward_rate_request(hw, req, parent, &req_parent, target_rate); + if (__clk_determine_rate(parent, &req_parent)) + return 0; + + if (abs(req_parent.rate - target_rate) < abs(req->rate - target_rate)) { + req->rate = req_parent.rate; + req->best_parent_rate = req_parent.rate; + } + + return 0; } static const struct clk_ops imx8m_clk_composite_divider_ops = { @@ -198,6 +223,33 @@ static const struct clk_ops imx8m_clk_composite_mux_ops = { .determine_rate = imx8m_clk_composite_mux_determine_rate, }; +static int imx8m_clk_composite_notifier_fn(struct notifier_block *notifier, + unsigned long code, void *data) +{ + struct clk_notifier_data *cnd = data; + struct clk_hw *hw = __clk_get_hw(cnd->clk); + + if (code != PRE_RATE_CHANGE) + return NOTIFY_OK; + + if (!__clk_is_rate_set(cnd->clk)) + return NOTIFY_OK; + + /* + * Consumer of a composite-m8 clock usually use the root clk, a gate + * connected to the composite (e.g. media_ldb and media_ldb_root). + * Therefore, evaluate the trigger's parent too. + */ + if (cnd->clk != cnd->trigger && cnd->clk != clk_get_parent(cnd->trigger)) + return notifier_from_errno(clk_hw_set_rate(hw, cnd->old_rate)); + + return NOTIFY_OK; +} + +static struct notifier_block imx8m_clk_composite_notifier = { + .notifier_call = imx8m_clk_composite_notifier_fn, +}; + struct clk_hw *__imx8m_clk_hw_composite(const char *name, const char * const *parent_names, int num_parents, void __iomem *reg, @@ -211,6 +263,7 @@ struct clk_hw *__imx8m_clk_hw_composite(const char *name, struct clk_mux *mux = NULL; const struct clk_ops *divider_ops; const struct clk_ops *mux_ops; + int ret; mux = kzalloc(sizeof(*mux), GFP_KERNEL); if (!mux) @@ -268,6 +321,18 @@ struct clk_hw *__imx8m_clk_hw_composite(const char *name, if (IS_ERR(hw)) goto fail; + /* + * register a notifier which should switch back to the configured rate + * if the rate is going to be changed unintentionally. + */ + if (flags & CLK_SET_RATE_PARENT) { + ret = clk_notifier_register(hw->clk, &imx8m_clk_composite_notifier); + if (ret) { + hw = ERR_PTR(ret); + goto fail; + } + } + return hw; fail: