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charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Artur, On 12/20/19 13:56, Artur Świgoń wrote: > This patch adds interconnect functionality to the exynos-bus devfreq > driver. > > The SoC topology is a graph (or, more specifically, a tree) and its > edges are specified using the 'exynos,interconnect-parent-node' in the > DT. Due to unspecified relative probing order, -EPROBE_DEFER may be > propagated to ensure that the parent is probed before its children. > > 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 Just to note that usually the provider consists of multiple nodes and each node represents a single master or slave port on the AXI bus for example. I am not sure whether this represents correctly the Exynos hardware, so it's up to you. > runtime, in probing order (subject to the above-mentioned exception > regarding relative order). This approach allows for using this driver with > various Exynos SoCs. This sounds good. I am wondering whether such dynamic probing would be useful for other platforms too. Then maybe it would make sense to even have a common DT property, but we will see. Is this going to be used only together with devfreq? > 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. How about the case where CONFIG_INTERCONNECT=m. Looks like the build will fail if CONFIG_ARM_EXYNOS_BUS_DEVFREQ=y, so this dependency should be expressed in Kconfig. Thanks, Georgi > > Signed-off-by: Artur Świgoń > --- > drivers/devfreq/exynos-bus.c | 144 +++++++++++++++++++++++++++++++++++ > 1 file changed, 144 insertions(+) > > diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c > index 9fdb188915e8..694a9581dcdb 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 kbps_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; > }; > > /* > @@ -205,6 +216,39 @@ 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 = kbps_to_khz(src->avg_bw); > + s32 dst_freq = kbps_to_khz(dst->avg_bw); > + int ret; > + > + ret = dev_pm_qos_update_request(&src_bus->qos_req, src_freq); > + if (ret < 0) { > + dev_err(src_bus->dev, "failed to update PM QoS request"); > + return ret; > + } > + > + ret = dev_pm_qos_update_request(&dst_bus->qos_req, dst_freq); > + if (ret < 0) { > + dev_err(dst_bus->dev, "failed to update PM QoS request"); > + return ret; > + } > + > + 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) > { > @@ -419,6 +463,96 @@ static int exynos_bus_profile_init_passive(struct exynos_bus *bus, > return 0; > } > > +static struct icc_node *exynos_bus_icc_get_parent(struct exynos_bus *bus) > +{ > + struct device_node *np = bus->dev->of_node; > + struct of_phandle_args args; > + int num, ret; > + > + num = of_count_phandle_with_args(np, "exynos,interconnect-parent-node", > + "#interconnect-cells"); > + if (num != 1) > + return NULL; /* parent nodes are optional */ > + > + ret = of_parse_phandle_with_args(np, "exynos,interconnect-parent-node", > + "#interconnect-cells", 0, &args); > + if (ret < 0) > + return ERR_PTR(ret); > + > + of_node_put(args.np); > + > + return of_icc_get_from_provider(&args); > +} > + > +static int exynos_bus_icc_init(struct exynos_bus *bus) > +{ > + static DEFINE_IDA(ida); > + > + struct device *dev = bus->dev; > + struct icc_provider *provider = &bus->provider; > + struct icc_node *node, *parent_node; > + int id, ret; > + > + /* Initialize the interconnect provider */ > + provider->set = exynos_bus_icc_set; > + provider->aggregate = icc_std_aggregate; > + provider->xlate = exynos_bus_icc_xlate; > + provider->dev = dev; > + provider->inter_set = true; > + provider->data = bus; > + > + ret = icc_provider_add(provider); > + if (ret < 0) > + return ret; > + > + ret = id = ida_alloc(&ida, GFP_KERNEL); > + if (ret < 0) > + goto err_id; > + > + 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); > + > + parent_node = exynos_bus_icc_get_parent(bus); > + if (IS_ERR(parent_node)) { > + ret = PTR_ERR(parent_node); > + goto err_parent; > + } > + > + if (parent_node) { > + ret = icc_link_create(node, parent_node->id); > + if (ret < 0) > + goto err_parent; > + } > + > + ret = dev_pm_qos_add_request(bus->devfreq->dev.parent, &bus->qos_req, > + DEV_PM_QOS_MIN_FREQUENCY, 0); > + if (ret < 0) > + goto err_request; > + > + return 0; > + > +err_request: > + if (parent_node) > + icc_link_destroy(node, parent_node); > +err_parent: > + icc_node_del(node); > + icc_node_destroy(id); > +err_node: > + ida_free(&ida, id); > +err_id: > + icc_provider_del(provider); > + > + return ret; > +} > + > static int exynos_bus_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > @@ -468,6 +602,16 @@ 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) { > + dev_err(dev, "failed to initialize the interconnect provider"); > + 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); >