From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Artur=20=C5=9Awigo=C5=84?= Subject: [RFC PATCH v2 09/11] devfreq: exynos-bus: Add interconnect functionality to exynos-bus Date: Thu, 19 Sep 2019 16:22:34 +0200 Message-ID: <20190919142236.4071-10-a.swigon@samsung.com> References: <20190919142236.4071-1-a.swigon@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190919142236.4071-1-a.swigon@samsung.com> Sender: linux-kernel-owner@vger.kernel.org To: 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: =?UTF-8?q?Artur=20=C5=9Awigo=C5=84?= , cw00.choi@samsung.com, 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 List-Id: linux-samsung-soc@vger.kernel.org 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); -- 2.17.1