This patch adds a generic interconnect driver for Exynos SoCs in order to provide interconnect functionality for each "samsung,exynos-bus" compatible device.
The SoC topology is a graph (or more specifically, a tree) and its edges are specified using the 'samsung,interconnect-parent' 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 dynamically at runtime. 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.
The bus-width DT property is to determine the interconnect data width and traslate requested bandwidth to clock frequency for each bus.
Signed-off-by: Artur Świgoń a.swigon@samsung.com Signed-off-by: Sylwester Nawrocki s.nawrocki@samsung.com --- Changes for v6: - corrected of_node dereferencing in exynos_icc_get_parent() function, - corrected initialization of icc_node->name so as to avoid direct of_node->name dereferencing, - added parsing of bus-width DT property, - use IS_ERR_OR_NULL in exynos_icc_genberic_remove().
Changes for v5: - adjust to renamed exynos,interconnect-parent-node property, - use automatically generated platform device id as the interconect node id instead of a now unavailable devfreq->id field, - add icc_ prefix to some variables to make the code more self-commenting, - use icc_nodes_remove() instead of icc_node_del() + icc_node_destroy(), - adjust to exynos,interconnect-parent-node property rename to samsung,interconnect-parent, - converted to a separate platform driver in drivers/interconnect. --- drivers/interconnect/Kconfig | 1 + drivers/interconnect/Makefile | 1 + drivers/interconnect/exynos/Kconfig | 6 ++ drivers/interconnect/exynos/Makefile | 4 + drivers/interconnect/exynos/exynos.c | 192 +++++++++++++++++++++++++++++++++++ 5 files changed, 204 insertions(+) create mode 100644 drivers/interconnect/exynos/Kconfig create mode 100644 drivers/interconnect/exynos/Makefile create mode 100644 drivers/interconnect/exynos/exynos.c
diff --git a/drivers/interconnect/Kconfig b/drivers/interconnect/Kconfig index 5b7204e..eca6eda 100644 --- a/drivers/interconnect/Kconfig +++ b/drivers/interconnect/Kconfig @@ -11,6 +11,7 @@ menuconfig INTERCONNECT
if INTERCONNECT
+source "drivers/interconnect/exynos/Kconfig" source "drivers/interconnect/imx/Kconfig" source "drivers/interconnect/qcom/Kconfig"
diff --git a/drivers/interconnect/Makefile b/drivers/interconnect/Makefile index 4825c28..2ba1de6 100644 --- a/drivers/interconnect/Makefile +++ b/drivers/interconnect/Makefile @@ -4,5 +4,6 @@ CFLAGS_core.o := -I$(src) icc-core-objs := core.o
obj-$(CONFIG_INTERCONNECT) += icc-core.o +obj-$(CONFIG_INTERCONNECT_EXYNOS) += exynos/ obj-$(CONFIG_INTERCONNECT_IMX) += imx/ obj-$(CONFIG_INTERCONNECT_QCOM) += qcom/ diff --git a/drivers/interconnect/exynos/Kconfig b/drivers/interconnect/exynos/Kconfig new file mode 100644 index 0000000..e51e52e --- /dev/null +++ b/drivers/interconnect/exynos/Kconfig @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0-only +config INTERCONNECT_EXYNOS + tristate "Exynos generic interconnect driver" + depends on ARCH_EXYNOS || COMPILE_TEST + help + Generic interconnect driver for Exynos SoCs. diff --git a/drivers/interconnect/exynos/Makefile b/drivers/interconnect/exynos/Makefile new file mode 100644 index 0000000..e19d1df --- /dev/null +++ b/drivers/interconnect/exynos/Makefile @@ -0,0 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 +exynos-interconnect-objs := exynos.o + +obj-$(CONFIG_INTERCONNECT_EXYNOS) += exynos-interconnect.o diff --git a/drivers/interconnect/exynos/exynos.c b/drivers/interconnect/exynos/exynos.c new file mode 100644 index 0000000..6c47a62 --- /dev/null +++ b/drivers/interconnect/exynos/exynos.c @@ -0,0 +1,192 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Exynos generic interconnect provider driver + * + * Copyright (c) 2020 Samsung Electronics Co., Ltd. + * + * Authors: Artur Świgoń a.swigon@samsung.com + * Sylwester Nawrocki s.nawrocki@samsung.com + */ +#include <linux/device.h> +#include <linux/interconnect-provider.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pm_qos.h> + +#define EXYNOS_ICC_DEFAULT_BUS_WIDTH 8 + +struct exynos_icc_priv { + struct device *dev; + + /* One interconnect node per provider */ + struct icc_provider provider; + struct icc_node *node; + + struct dev_pm_qos_request qos_req; + u32 bus_width; +}; + +static struct icc_node *exynos_icc_get_parent(struct device_node *np) +{ + struct of_phandle_args args; + struct icc_node *icc_np; + int num, ret; + + num = of_count_phandle_with_args(np, "samsung,interconnect-parent", + "#interconnect-cells"); + if (num != 1) + return NULL; /* parent nodes are optional */ + + ret = of_parse_phandle_with_args(np, "samsung,interconnect-parent", + "#interconnect-cells", 0, &args); + if (ret < 0) + return ERR_PTR(ret); + + icc_np = of_icc_get_from_provider(&args); + of_node_put(args.np); + + return icc_np; +} + +static int exynos_generic_icc_set(struct icc_node *src, struct icc_node *dst) +{ + struct exynos_icc_priv *src_priv = src->data, *dst_priv = dst->data; + s32 src_freq = max(src->avg_bw, src->peak_bw) / src_priv->bus_width; + s32 dst_freq = max(dst->avg_bw, dst->peak_bw) / dst_priv->bus_width; + int ret; + + ret = dev_pm_qos_update_request(&src_priv->qos_req, src_freq); + if (ret < 0) { + dev_err(src_priv->dev, "failed to update PM QoS of %s\n", + src->name); + return ret; + } + + ret = dev_pm_qos_update_request(&dst_priv->qos_req, dst_freq); + if (ret < 0) { + dev_err(dst_priv->dev, "failed to update PM QoS of %s\n", + dst->name); + return ret; + } + + return 0; +} + +static struct icc_node *exynos_generic_icc_xlate(struct of_phandle_args *spec, + void *data) +{ + struct exynos_icc_priv *priv = data; + + if (spec->np != priv->dev->parent->of_node) + return ERR_PTR(-EINVAL); + + return priv->node; +} + +static int exynos_generic_icc_remove(struct platform_device *pdev) +{ + struct exynos_icc_priv *priv = platform_get_drvdata(pdev); + struct icc_node *parent_node, *node = priv->node; + + parent_node = exynos_icc_get_parent(priv->dev->parent->of_node); + if (!IS_ERR_OR_NULL(parent_node)) + icc_link_destroy(node, parent_node); + + icc_nodes_remove(&priv->provider); + icc_provider_del(&priv->provider); + + return 0; +} + +static int exynos_generic_icc_probe(struct platform_device *pdev) +{ + struct device *bus_dev = pdev->dev.parent; + struct exynos_icc_priv *priv; + struct icc_provider *provider; + struct icc_node *icc_node, *icc_parent_node; + int ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->dev = &pdev->dev; + platform_set_drvdata(pdev, priv); + + provider = &priv->provider; + + provider->set = exynos_generic_icc_set; + provider->aggregate = icc_std_aggregate; + provider->xlate = exynos_generic_icc_xlate; + provider->dev = bus_dev; + provider->inter_set = true; + provider->data = priv; + + ret = icc_provider_add(provider); + if (ret < 0) + return ret; + + icc_node = icc_node_create(pdev->id); + if (IS_ERR(icc_node)) { + ret = PTR_ERR(icc_node); + goto err_prov_del; + } + + priv->node = icc_node; + icc_node->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn", + bus_dev->of_node); + if (of_property_read_u32(bus_dev->of_node, "bus-width", + &priv->bus_width)) + priv->bus_width = EXYNOS_ICC_DEFAULT_BUS_WIDTH; + + icc_node->data = priv; + icc_node_add(icc_node, provider); + + icc_parent_node = exynos_icc_get_parent(bus_dev->of_node); + if (IS_ERR(icc_parent_node)) { + ret = PTR_ERR(icc_parent_node); + goto err_node_del; + } + if (icc_parent_node) { + ret = icc_link_create(icc_node, icc_parent_node->id); + if (ret < 0) + goto err_node_del; + } + + /* + * Register a PM QoS request for the bus device for which also devfreq + * functionality is registered. + */ + ret = dev_pm_qos_add_request(bus_dev, &priv->qos_req, + DEV_PM_QOS_MIN_FREQUENCY, 0); + if (ret < 0) + goto err_link_destroy; + + return 0; + +err_link_destroy: + if (icc_parent_node) + icc_link_destroy(icc_node, icc_parent_node); +err_node_del: + icc_nodes_remove(provider); +err_prov_del: + icc_provider_del(provider); + + return ret; +} + +static struct platform_driver exynos_generic_icc_driver = { + .driver = { + .name = "exynos-generic-icc", + }, + .probe = exynos_generic_icc_probe, + .remove = exynos_generic_icc_remove, +}; +module_platform_driver(exynos_generic_icc_driver); + +MODULE_DESCRIPTION("Exynos generic interconnect driver"); +MODULE_AUTHOR("Artur Świgoń a.swigon@samsung.com"); +MODULE_AUTHOR("Sylwester Nawrocki s.nawrocki@samsung.com"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:exynos-generic-icc");