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Fri, 8 May 2020 13:59:41 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEFEEC05BD0B for ; Fri, 8 May 2020 10:59:40 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id n11so1198778pgl.9 for ; Fri, 08 May 2020 10:59:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=oRpq+jLekVUTOI/QQLf26wWsNl1b7bpxHYpAdZmr4rw=; b=hVWURPAIPfmGWKrNxFIruXSjviWO/yuaURKHe/STcvMBAz+n6q1OPUNQVzqmJrBtX9 tHUylZML8w4w0YaP8mcJk0ov2Zf9wDQoGLlg72Mc0q/wZuEkFv1qsjbz1FQ9s21DpXYv ctDfE5n4gaT2MU/IGGsQGqQzNGp+TQmTW1RgY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=oRpq+jLekVUTOI/QQLf26wWsNl1b7bpxHYpAdZmr4rw=; 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charset=utf-8 Content-Disposition: inline In-Reply-To: <1588919619-21355-3-git-send-email-akashast@codeaurora.org> Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Hi Akash, overall this looks good to me, a few comments inline On Fri, May 08, 2020 at 12:03:34PM +0530, Akash Asthana wrote: > QUP core clock is shared among all the SE drivers present on particular > QUP wrapper, the system will reset(unclocked access) if earlycon used after > QUP core clock is put to 0 from other SE drivers before real console comes > up. > > As earlycon can't vote for it's QUP core need, to fix this add ICC > support to common/QUP wrapper driver and put vote for QUP core from > probe on behalf of earlycon and remove vote during earlycon exit call. > > Signed-off-by: Akash Asthana > Reported-by: Matthias Kaehlcke > --- > Change in V3: > - Add geni_remove_earlycon_icc_vote API that will be used by earlycon > exit function to remove ICC vote for earlyconsole. > - Remove suspend/resume hook for geni-se driver as we are no longer > removing earlyconsole ICC vote from system suspend, we are removing > from earlycon exit. > > Change in V4: > - As per Matthias comment make 'earlycon_wrapper' as static structure. > > Changes in V5: > - Vote for core path only after checking whether "qcom_geni" earlycon is > actually present or not by traversing over structure "console_drivers". > > drivers/soc/qcom/qcom-geni-se.c | 63 +++++++++++++++++++++++++++++++++++ > drivers/tty/serial/qcom_geni_serial.c | 7 ++++ > include/linux/qcom-geni-se.h | 2 ++ > 3 files changed, 72 insertions(+) > > diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c > index 63403bf..66fe6f2 100644 > --- a/drivers/soc/qcom/qcom-geni-se.c > +++ b/drivers/soc/qcom/qcom-geni-se.c > @@ -3,6 +3,7 @@ > > #include > #include > +#include > #include > #include > #include > @@ -90,11 +91,14 @@ struct geni_wrapper { > struct device *dev; > void __iomem *base; > struct clk_bulk_data ahb_clks[NUM_AHB_CLKS]; > + struct geni_icc_path to_core; > }; > > static const char * const icc_path_names[] = {"qup-core", "qup-config", > "qup-memory"}; > > +static struct geni_wrapper *earlycon_wrapper; > + > #define QUP_HW_VER_REG 0x4 > > /* Common SE registers */ > @@ -812,11 +816,33 @@ int geni_icc_disable(struct geni_se *se) > } > EXPORT_SYMBOL(geni_icc_disable); > > +void geni_remove_earlycon_icc_vote(void) > +{ > + struct geni_wrapper *wrapper = earlycon_wrapper; > + struct device_node *parent = of_get_next_parent(wrapper->dev->of_node); Do we need to check that earlycon_wrapper != NULL before dereferencing it? In theory this should not happen, but better be safe. > + struct device_node *child; > + > + for_each_child_of_node(parent, child) { > + if (of_device_is_compatible(child, "qcom,geni-se-qup")) { > + wrapper = platform_get_drvdata(of_find_device_by_node( > + child)); > + icc_put(wrapper->to_core.path); > + wrapper->to_core.path = NULL; nit: setting the path to NULL isn't really needed IIUC. > + } > + } > + of_node_put(parent); > + > + earlycon_wrapper = NULL; > +} > +EXPORT_SYMBOL(geni_remove_earlycon_icc_vote); > + > static int geni_se_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > struct resource *res; > struct geni_wrapper *wrapper; > + struct console *bcon; > + int earlycon_present = 0; use bool & true/false The variable is only used when CONFIG_SERIAL_EARLYCON is set, I think you need to add '__maybe_unused' to avoid a compiler warning then earlycon support is disabled. bikeshed: 'has_earlycon' would be slightly more concise (feel free to ignore). > int ret; > > wrapper = devm_kzalloc(dev, sizeof(*wrapper), GFP_KERNEL); > @@ -839,6 +865,43 @@ static int geni_se_probe(struct platform_device *pdev) > } > } > > +#ifdef CONFIG_SERIAL_EARLYCON > + if (console_drivers) The loop should have curly braces ("use braces when a loop contains more than a single simple statement"), even though the compiler doesn't need them in this case. This is not a loop, but I was told by a maintainer that it equally applies, which makes sense. You could avoid one level of indentation through: if (!console_drivers) goto exit; > + for_each_console(bcon) ditto (braces) > + if (!strcmp(bcon->name, "qcom_geni")) { > + earlycon_present = 1; > + break; > + } > + if (!earlycon_present) > + goto exit; > + > + wrapper->to_core.path = devm_of_icc_get(dev, "qup-core"); > + if (IS_ERR(wrapper->to_core.path)) > + return PTR_ERR(wrapper->to_core.path); > + /* > + * Put minmal BW request on core clocks on behalf of early console. > + * The vote will be removed earlycon exit function. > + * > + * Note: We are putting vote on each QUP wrapper instead only to which > + * earlycon is connected because QUP core clock of different wrapper > + * share same voltage domain. If core1 is put to 0, then core2 will > + * also run at 0, if not voted. Default ICC vote will be removed ASA > + * we touch any of the core clock. > + * core1 = core2 = max(core1, core2) > + */ > + ret = icc_set_bw(wrapper->to_core.path, GENI_DEFAULT_BW, > + GENI_DEFAULT_BW); nit: the indentation is a bit odd. Align with 'wrapper->to_core.path' or a nearby tab stop?