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Wed, 25 Sep 2019 07:12:45 +0000 (GMT) Message-ID: <9b6a744b732e2cbf95df4da203f94a039a39af21.camel@samsung.com> Subject: Re: [RFC PATCH v2 09/11] devfreq: exynos-bus: Add interconnect functionality to exynos-bus From: Artur =?UTF-8?Q?=C5=9Awigo=C5=84?= To: Chanwoo Choi , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: Artur =?UTF-8?Q?=C5=9Awigo=C5=84?= , myungjoo.ham@samsung.com, inki.dae@samsung.com, sw0312.kim@samsung.com, georgi.djakov@linaro.org, leonard.crestez@nxp.com, m.szyprowski@samsung.com, b.zolnierkie@samsung.com, krzk@kernel.org Date: Wed, 25 Sep 2019 09:12:45 +0200 In-Reply-To: X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: H4sIAAAAAAAAA01SaUwTYRD16x5dqiVLQZkg0diIB/HGhI0HYKJmf3n+QkN0kQ2itCVdwAON HHIrIBjAWo9EkCsNUDkqKhJsxACKAgEFGkjkiCiXgIIiSrsQ/PfmzXvzZpKhMEUz4UIFqUN5 rZoLVpIyvOL1dNNmtWOy37aG2fVM9/1YxJRmFxNM+8QAwTwwvyOY1skRksl6YSSZ9O40nGlq KpEy+ZYxgjF+biOYlio9yYzfNCMmu6lawhjMFinTGZVPMtkZX0gfmjUWJpJsV9tzku1OrpOw T3KusaXDJgmbUlaI2HHjqiPSE7I9AXxwUDiv3ep1Wnb29614LGTq4MWSrnxpJDJ5JiE7Cuid EP8tDU9CMkpB5yMoLTNhYjGBoCavkBSLcQQ9Od+lC5bO1sR5VR6Cjpjq+aIfQdF0O2lVyWkW ckyNmBU70jzoDZU2TNLe8Lbzh8RqcKKHEfS+HLW5Mfq6BAZ0g3OrUBROu8GzvrVWaDdn6Go8 LiZvgqH6FJtCTjvAH5Ojlcbo1RBTftc2BehJKdTcbydE/X5ITXhKitgRBuvK5i9whYaMG7iI Beh72k2I5kgExsdmTGzshld1HwhrGEZvhOKqrSK9DxqjO2w7AG0PH4ccxB3sIb0iCxNpOSTE KUSohKo79qIRILqobX42C2UxejwNrdEt3qL77xbdYupDhBUiZz5MUAXygoeav7BF4FRCmDpw yxmNyojmPq1htm7ShKpn/GsRTSHlMrkPkeSnILhw4ZKqFgGFKZ3kOtc5Sh7AXbrMazWntGHB vFCLVlK40lkesaTnpIIO5EL58zwfwmsXuhLKziUS1RftMntWBBd4se8jDlx+lNqbh5fL9Rmq pX97vFsCoqISZW/6RzUFa92yfUoOh5PN55Z/7fV/sMP3yrtj/pU/zZmcZuTXVQ+V2lR+x7XX b3A0RePhstkycHtFrmYmN9HBsiGGyzy299M6B29DyL24MYt+yr3lkFd09dHpcMmIwTdWiQtn ue3umFbg/gFJ5/arZQMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrFIsWRmVeSWpSXmKPExsVy+t/xe7p5wt2xBt172Czuz2tltNg4Yz2r xfUvz1kt5h85x2px5et7NovpezexWUy6P4HF4vz5DewWK+5+ZLXY9Pgaq8XlXXPYLD73HmG0 mHF+H5PF2iN32S1uN65gs5gx+SWbg4DHplWdbB53ru1h87jffZzJY/OSeo+N73YwefRtWcXo 8XmTXAB7lJ5NUX5pSapCRn5xia1StKGFkZ6hpYWekYmlnqGxeayVkamSvp1NSmpOZllqkb5d gl7G74ntzAU/3Co23FnB3sC4w7yLkZNDQsBE4vaVTuYuRi4OIYGljBIrzh5ihEhISHxcf4MV whaW+HOtiw2i6AmjxNH2T2wgCV4BD4klO84wg9jCAqkSc9ZuB7PZBOwlzt7+xgTSICLwnlHi w/Z37CAOs0Abk8Shvs1AYzk4WARUJXY/VQExOYEa7pwJhljwhVHi9ImZYJuZBTQlWrf/Zoe4 Qkfi7ak+FpB6XgFBib87hCFK5CWat85mnsAoOAtJxyyEqllIqhYwMq9iFEktLc5Nzy021CtO zC0uzUvXS87P3cQIjNdtx35u3sF4aWPwIUYBDkYlHl4H1q5YIdbEsuLK3EOMEhzMSiK8s2SA QrwpiZVVqUX58UWlOanFhxhNgb6ZyCwlmpwPTCV5JfGGpobmFpaG5sbmxmYWSuK8HQIHY4QE 0hNLUrNTUwtSi2D6mDg4pRoYc+qe7TrXcM66S+/4g85rqzPMJbKXzrVvm9s1J2ae26GVOg4L c1l0+nSlfXuUXQLXOQcYP/zj/lFETaFUparp+onTHwOr3Y2d2ViCZfXO71hgl/Hy7Ias+Rqr BN4qPn733Ndv85UQxYLVbyayCDwSfmwtKzDz4omWS0kzW0tDWcS+6/9bzdqhxFKckWioxVxU nAgAgGARVu0CAAA= X-CMS-MailID: 20190925071246eucas1p2df0c05c3910aa1b0de48cf044c2aba1d X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20190919142329eucas1p2e53992eab9ec6b404f716f955b3c228e X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20190919142329eucas1p2e53992eab9ec6b404f716f955b3c228e References: <20190919142236.4071-1-a.swigon@samsung.com> <20190919142236.4071-10-a.swigon@samsung.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Wed, 2019-09-25 at 16:03 +0900, Chanwoo Choi wrote: > Hi, > > I need the time to dig the ICC framework > to understand them detailed. After that, I'll review this. > > Basically, I agree this approach. But, I'm wondering > the existing binding method between 'bus_leftbus' and 'bus_dmc'. > From before, I thought that devfreq framework need to > enhance the binding method between parent devfreq device > and passive devfreq device instead of 'devfreq' property. > > On this patch, use the same binding way between > 'bus_leftbus' and 'bus_dmc' with 'parent' property > as following: > > +++ b/arch/arm/boot/dts/exynos4412-odroid-common.dtsi > @@ -106,6 +106,7 @@ > &bus_leftbus { > devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>; > vdd-supply = <&buck3_reg>; > + parent = <&bus_dmc>; > status = "okay"; > }; > > I'm not sure about continuing to use this method for new feature. > If possible, hope to replace the existing binding style > with new method like of_graph. Actually, I don't know the correct method. Adding the 'parent' binding was the simplest solution to create this RFC to show the concept of using interconnect functionality in devfreq. I agree that a method like of_graph is probably more elegant. I am open to suggestions. > On 19. 9. 19. 오후 11:22, Artur Świgoń wrote: > > From: Artur Świgoń > > > > This patch adds interconnect functionality to the exynos-bus devfreq > > driver. > > > > The SoC topology is a graph (or, more specifically, a tree) and most of > > its edges are taken from the devfreq parent-child hierarchy (cf. > > Documentation/devicetree/bindings/devfreq/exynos-bus.txt). Due to > > unspecified relative probing order, -EPROBE_DEFER may be propagated to > > guarantee that a child is probed before its parent. > > > > Each bus is now an interconnect provider and an interconnect node as well > > (cf. Documentation/interconnect/interconnect.rst), i.e. every bus registers > > itself as a node. Node IDs are not hardcoded but rather assigned at > > runtime, in probing order (subject to the above-mentioned exception > > regarding relative order). This approach allows for using this driver with > > various Exynos SoCs. > > > > Frequencies requested via the interconnect API for a given node are > > propagated to devfreq using dev_pm_qos_update_request(). Please note that > > it is not an error when CONFIG_INTERCONNECT is 'n', in which case all > > interconnect API functions are no-op. > > > > Signed-off-by: Artur Świgoń > > --- > > drivers/devfreq/exynos-bus.c | 153 +++++++++++++++++++++++++++++++++++ > > 1 file changed, 153 insertions(+) > > > > diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c > > index 8d44810cac69..e0232202720d 100644 > > --- a/drivers/devfreq/exynos-bus.c > > +++ b/drivers/devfreq/exynos-bus.c > > @@ -14,14 +14,19 @@ > > #include > > #include > > #include > > +#include > > +#include > > #include > > #include > > #include > > +#include > > #include > > #include > > > > #define DEFAULT_SATURATION_RATIO 40 > > > > +#define icc_units_to_khz(x) ((x) / 8) > > + > > struct exynos_bus { > > struct device *dev; > > > > @@ -35,6 +40,12 @@ struct exynos_bus { > > struct opp_table *opp_table; > > struct clk *clk; > > unsigned int ratio; > > + > > + /* One provider per bus, one node per provider */ > > + struct icc_provider provider; > > + struct icc_node *node; > > + > > + struct dev_pm_qos_request qos_req; > > }; > > > > /* > > @@ -59,6 +70,13 @@ exynos_bus_ops_edev(enable_edev); > > exynos_bus_ops_edev(disable_edev); > > exynos_bus_ops_edev(set_event); > > > > +static int exynos_bus_next_id(void) > > +{ > > + static DEFINE_IDA(exynos_bus_icc_ida); > > + > > + return ida_alloc(&exynos_bus_icc_ida, GFP_KERNEL); > > +} > > + > > static int exynos_bus_get_event(struct exynos_bus *bus, > > struct devfreq_event_data *edata) > > { > > @@ -171,6 +189,38 @@ static void exynos_bus_passive_exit(struct device *dev) > > clk_disable_unprepare(bus->clk); > > } > > > > +static int exynos_bus_icc_set(struct icc_node *src, struct icc_node *dst) > > +{ > > + struct exynos_bus *src_bus = src->data, *dst_bus = dst->data; > > + s32 src_freq = icc_units_to_khz(src->avg_bw); > > + s32 dst_freq = icc_units_to_khz(dst->avg_bw); > > + > > + dev_pm_qos_update_request(&src_bus->qos_req, src_freq); > > + dev_pm_qos_update_request(&dst_bus->qos_req, dst_freq); > > + > > + return 0; > > +} > > + > > +static int exynos_bus_icc_aggregate(struct icc_node *node, u32 tag, u32 avg_bw, > > + u32 peak_bw, u32 *agg_avg, u32 *agg_peak) > > +{ > > + *agg_avg += avg_bw; > > + *agg_peak = max(*agg_peak, peak_bw); > > + > > + return 0; > > +} > > + > > +static struct icc_node *exynos_bus_icc_xlate(struct of_phandle_args *spec, > > + void *data) > > +{ > > + struct exynos_bus *bus = data; > > + > > + if (spec->np != bus->dev->of_node) > > + return ERR_PTR(-EINVAL); > > + > > + return bus->node; > > +} > > + > > static int exynos_bus_parent_parse_of(struct device_node *np, > > struct exynos_bus *bus) > > { > > @@ -366,6 +416,101 @@ static int exynos_bus_profile_init_passive(struct exynos_bus *bus, > > return 0; > > } > > > > +static int exynos_bus_icc_connect(struct exynos_bus *bus) > > +{ > > + struct device_node *np = bus->dev->of_node; > > + struct devfreq *parent_devfreq; > > + struct icc_node *parent_node = NULL; > > + struct of_phandle_args args; > > + int ret = 0; > > + > > + parent_devfreq = devfreq_get_devfreq_by_phandle(bus->dev, 0); > > + if (!IS_ERR(parent_devfreq)) { > > + struct exynos_bus *parent_bus; > > + > > + parent_bus = dev_get_drvdata(parent_devfreq->dev.parent); > > + parent_node = parent_bus->node; > > + } else { > > + /* Look for parent in DT */ > > + int num = of_count_phandle_with_args(np, "parent", > > + "#interconnect-cells"); > > + if (num != 1) > > + goto out; /* 'parent' is optional */ > > + > > + ret = of_parse_phandle_with_args(np, "parent", > > + "#interconnect-cells", > > + 0, &args); > > + if (ret < 0) > > + goto out; > > + > > + of_node_put(args.np); > > + > > + parent_node = of_icc_get_from_provider(&args); > > + if (IS_ERR(parent_node)) { > > + /* May be -EPROBE_DEFER */ > > + ret = PTR_ERR(parent_node); > > + goto out; > > + } > > + } > > > > > + > > + ret = icc_link_create(bus->node, parent_node->id); > > + > > +out: > > + return ret; > > +} > > + > > +static int exynos_bus_icc_init(struct exynos_bus *bus) > > +{ > > + struct device *dev = bus->dev; > > + struct icc_provider *provider = &bus->provider; > > + struct icc_node *node; > > + int id, ret; > > + > > + /* Initialize the interconnect provider */ > > + provider->set = exynos_bus_icc_set; > > + provider->aggregate = exynos_bus_icc_aggregate; > > + provider->xlate = exynos_bus_icc_xlate; > > + provider->dev = dev; > > + provider->data = bus; > > + > > + ret = icc_provider_add(provider); > > + if (ret < 0) > > + goto out; > > + > > + ret = id = exynos_bus_next_id(); > > + if (ret < 0) > > + goto err_node; > > + > > + node = icc_node_create(id); > > + if (IS_ERR(node)) { > > + ret = PTR_ERR(node); > > + goto err_node; > > + } > > + > > + bus->node = node; > > + node->name = dev->of_node->name; > > + node->data = bus; > > + icc_node_add(node, provider); > > + > > + ret = exynos_bus_icc_connect(bus); > > + if (ret < 0) > > + goto err_connect; > > + > > + ret = dev_pm_qos_add_request(bus->devfreq->dev.parent, &bus->qos_req, > > + DEV_PM_QOS_MIN_FREQUENCY, 0); > > + > > +out: > > + return ret; > > + > > +err_connect: > > + icc_node_del(node); > > + icc_node_destroy(id); > > +err_node: > > + icc_provider_del(provider); > > + > > + return ret; > > +} > > + > > static int exynos_bus_probe(struct platform_device *pdev) > > { > > struct device *dev = &pdev->dev; > > @@ -415,6 +560,14 @@ static int exynos_bus_probe(struct platform_device *pdev) > > if (ret < 0) > > goto err; > > > > + /* > > + * Initialize interconnect provider. A return value of -ENOTSUPP means > > + * that CONFIG_INTERCONNECT is disabled. > > + */ > > + ret = exynos_bus_icc_init(bus); > > + if (ret < 0 && ret != -ENOTSUPP) > > + goto err; > > + > > max_state = bus->devfreq->profile->max_state; > > min_freq = (bus->devfreq->profile->freq_table[0] / 1000); > > max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000); > > > > -- Artur Świgoń Samsung R&D Institute Poland Samsung Electronics