From 1fc2dd1864c2b18860fb619caeee758504c3aac8 Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Wed, 1 Jul 2020 16:53:40 +0100 Subject: [PATCH] firmware: arm_scmi: Add notification protocol-registration Add the core SCMI notifications protocol-registration support: allow protocols to register their own set of supported events, during their initialization phase. Notification core can track multiple platform instances by their handles. Link: https://lore.kernel.org/r/20200701155348.52864-2-cristian.marussi@arm.com Reviewed-by: Jonathan Cameron Signed-off-by: Cristian Marussi Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/Makefile | 2 +- drivers/firmware/arm_scmi/common.h | 4 + drivers/firmware/arm_scmi/notify.c | 440 +++++++++++++++++++++++++++++++++++++ drivers/firmware/arm_scmi/notify.h | 56 +++++ include/linux/scmi_protocol.h | 3 + 5 files changed, 504 insertions(+), 1 deletion(-) create mode 100644 drivers/firmware/arm_scmi/notify.c create mode 100644 drivers/firmware/arm_scmi/notify.h diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile index 70c5a8c986a5..6f9cbc4aef22 100644 --- a/drivers/firmware/arm_scmi/Makefile +++ b/drivers/firmware/arm_scmi/Makefile @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0-only obj-y = scmi-bus.o scmi-driver.o scmi-protocols.o scmi-transport.o scmi-bus-y = bus.o -scmi-driver-y = driver.o +scmi-driver-y = driver.o notify.o scmi-transport-y = shmem.o scmi-transport-$(CONFIG_MAILBOX) += mailbox.o scmi-transport-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY) += smc.o diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h index 31fe5a22a011..c113e578cc6c 100644 --- a/drivers/firmware/arm_scmi/common.h +++ b/drivers/firmware/arm_scmi/common.h @@ -6,6 +6,8 @@ * * Copyright (C) 2018 ARM Ltd. */ +#ifndef _SCMI_COMMON_H +#define _SCMI_COMMON_H #include #include @@ -235,3 +237,5 @@ void shmem_fetch_notification(struct scmi_shared_mem __iomem *shmem, void shmem_clear_channel(struct scmi_shared_mem __iomem *shmem); bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem, struct scmi_xfer *xfer); + +#endif /* _SCMI_COMMON_H */ diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c new file mode 100644 index 000000000000..0505433043d8 --- /dev/null +++ b/drivers/firmware/arm_scmi/notify.c @@ -0,0 +1,440 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * System Control and Management Interface (SCMI) Notification support + * + * Copyright (C) 2020 ARM Ltd. + */ +/** + * DOC: Theory of operation + * + * SCMI Protocol specification allows the platform to signal events to + * interested agents via notification messages: this is an implementation + * of the dispatch and delivery of such notifications to the interested users + * inside the Linux kernel. + * + * An SCMI Notification core instance is initialized for each active platform + * instance identified by the means of the usual &struct scmi_handle. + * + * Each SCMI Protocol implementation, during its initialization, registers with + * this core its set of supported events using scmi_register_protocol_events(): + * all the needed descriptors are stored in the &struct registered_protocols and + * &struct registered_events arrays. + */ + +#define dev_fmt(fmt) "SCMI Notifications - " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "notify.h" + +#define SCMI_MAX_PROTO 256 + +#define PROTO_ID_MASK GENMASK(31, 24) +#define EVT_ID_MASK GENMASK(23, 16) +#define SRC_ID_MASK GENMASK(15, 0) + +/* + * Builds an unsigned 32bit key from the given input tuple to be used + * as a key in hashtables. + */ +#define MAKE_HASH_KEY(p, e, s) \ + (FIELD_PREP(PROTO_ID_MASK, (p)) | \ + FIELD_PREP(EVT_ID_MASK, (e)) | \ + FIELD_PREP(SRC_ID_MASK, (s))) + +#define MAKE_ALL_SRCS_KEY(p, e) MAKE_HASH_KEY((p), (e), SRC_ID_MASK) + +struct scmi_registered_events_desc; + +/** + * struct scmi_notify_instance - Represents an instance of the notification + * core + * @gid: GroupID used for devres + * @handle: A reference to the platform instance + * @registered_protocols: A statically allocated array containing pointers to + * all the registered protocol-level specific information + * related to events' handling + * + * Each platform instance, represented by a handle, has its own instance of + * the notification subsystem represented by this structure. + */ +struct scmi_notify_instance { + void *gid; + struct scmi_handle *handle; + struct scmi_registered_events_desc **registered_protocols; +}; + +/** + * struct events_queue - Describes a queue and its associated worker + * @sz: Size in bytes of the related kfifo + * @kfifo: A dedicated Kernel kfifo descriptor + * + * Each protocol has its own dedicated events_queue descriptor. + */ +struct events_queue { + size_t sz; + struct kfifo kfifo; +}; + +/** + * struct scmi_event_header - A utility header + * @timestamp: The timestamp, in nanoseconds (boottime), which was associated + * to this event as soon as it entered the SCMI RX ISR + * @evt_id: Event ID (corresponds to the Event MsgID for this Protocol) + * @payld_sz: Effective size of the embedded message payload which follows + * @payld: A reference to the embedded event payload + * + * This header is prepended to each received event message payload before + * queueing it on the related &struct events_queue. + */ +struct scmi_event_header { + u64 timestamp; + u8 evt_id; + size_t payld_sz; + u8 payld[]; +} __packed; + +struct scmi_registered_event; + +/** + * struct scmi_registered_events_desc - Protocol Specific information + * @id: Protocol ID + * @ops: Protocol specific and event-related operations + * @equeue: The embedded per-protocol events_queue + * @ni: A reference to the initialized instance descriptor + * @eh: A reference to pre-allocated buffer to be used as a scratch area by the + * deferred worker when fetching data from the kfifo + * @eh_sz: Size of the pre-allocated buffer @eh + * @in_flight: A reference to an in flight &struct scmi_registered_event + * @num_events: Number of events in @registered_events + * @registered_events: A dynamically allocated array holding all the registered + * events' descriptors, whose fixed-size is determined at + * compile time. + * + * All protocols that register at least one event have their protocol-specific + * information stored here, together with the embedded allocated events_queue. + * These descriptors are stored in the @registered_protocols array at protocol + * registration time. + * + * Once these descriptors are successfully registered, they are NEVER again + * removed or modified since protocols do not unregister ever, so that, once + * we safely grab a NON-NULL reference from the array we can keep it and use it. + */ +struct scmi_registered_events_desc { + u8 id; + const struct scmi_event_ops *ops; + struct events_queue equeue; + struct scmi_notify_instance *ni; + struct scmi_event_header *eh; + size_t eh_sz; + void *in_flight; + int num_events; + struct scmi_registered_event **registered_events; +}; + +/** + * struct scmi_registered_event - Event Specific Information + * @proto: A reference to the associated protocol descriptor + * @evt: A reference to the associated event descriptor (as provided at + * registration time) + * @report: A pre-allocated buffer used by the deferred worker to fill a + * customized event report + * @num_sources: The number of possible sources for this event as stated at + * events' registration time + * @sources: A reference to a dynamically allocated array used to refcount the + * events' enable requests for all the existing sources + * @sources_mtx: A mutex to serialize the access to @sources + * + * All registered events are represented by one of these structures that are + * stored in the @registered_events array at protocol registration time. + * + * Once these descriptors are successfully registered, they are NEVER again + * removed or modified since protocols do not unregister ever, so that once we + * safely grab a NON-NULL reference from the table we can keep it and use it. + */ +struct scmi_registered_event { + struct scmi_registered_events_desc *proto; + const struct scmi_event *evt; + void *report; + u32 num_sources; + refcount_t *sources; + /* locking to serialize the access to sources */ + struct mutex sources_mtx; +}; + +/** + * scmi_kfifo_free() - Devres action helper to free the kfifo + * @kfifo: The kfifo to free + */ +static void scmi_kfifo_free(void *kfifo) +{ + kfifo_free((struct kfifo *)kfifo); +} + +/** + * scmi_initialize_events_queue() - Allocate/Initialize a kfifo buffer + * @ni: A reference to the notification instance to use + * @equeue: The events_queue to initialize + * @sz: Size of the kfifo buffer to allocate + * + * Allocate a buffer for the kfifo and initialize it. + * + * Return: 0 on Success + */ +static int scmi_initialize_events_queue(struct scmi_notify_instance *ni, + struct events_queue *equeue, size_t sz) +{ + if (kfifo_alloc(&equeue->kfifo, sz, GFP_KERNEL)) + return -ENOMEM; + /* Size could have been roundup to power-of-two */ + equeue->sz = kfifo_size(&equeue->kfifo); + + return devm_add_action_or_reset(ni->handle->dev, scmi_kfifo_free, + &equeue->kfifo); +} + +/** + * scmi_allocate_registered_events_desc() - Allocate a registered events' + * descriptor + * @ni: A reference to the &struct scmi_notify_instance notification instance + * to use + * @proto_id: Protocol ID + * @queue_sz: Size of the associated queue to allocate + * @eh_sz: Size of the event header scratch area to pre-allocate + * @num_events: Number of events to support (size of @registered_events) + * @ops: Pointer to a struct holding references to protocol specific helpers + * needed during events handling + * + * It is supposed to be called only once for each protocol at protocol + * initialization time, so it warns if the requested protocol is found already + * registered. + * + * Return: The allocated and registered descriptor on Success + */ +static struct scmi_registered_events_desc * +scmi_allocate_registered_events_desc(struct scmi_notify_instance *ni, + u8 proto_id, size_t queue_sz, size_t eh_sz, + int num_events, + const struct scmi_event_ops *ops) +{ + int ret; + struct scmi_registered_events_desc *pd; + + /* Ensure protocols are up to date */ + smp_rmb(); + if (WARN_ON(ni->registered_protocols[proto_id])) + return ERR_PTR(-EINVAL); + + pd = devm_kzalloc(ni->handle->dev, sizeof(*pd), GFP_KERNEL); + if (!pd) + return ERR_PTR(-ENOMEM); + pd->id = proto_id; + pd->ops = ops; + pd->ni = ni; + + ret = scmi_initialize_events_queue(ni, &pd->equeue, queue_sz); + if (ret) + return ERR_PTR(ret); + + pd->eh = devm_kzalloc(ni->handle->dev, eh_sz, GFP_KERNEL); + if (!pd->eh) + return ERR_PTR(-ENOMEM); + pd->eh_sz = eh_sz; + + pd->registered_events = devm_kcalloc(ni->handle->dev, num_events, + sizeof(char *), GFP_KERNEL); + if (!pd->registered_events) + return ERR_PTR(-ENOMEM); + pd->num_events = num_events; + + return pd; +} + +/** + * scmi_register_protocol_events() - Register Protocol Events with the core + * @handle: The handle identifying the platform instance against which the + * the protocol's events are registered + * @proto_id: Protocol ID + * @queue_sz: Size in bytes of the associated queue to be allocated + * @ops: Protocol specific event-related operations + * @evt: Event descriptor array + * @num_events: Number of events in @evt array + * @num_sources: Number of possible sources for this protocol on this + * platform. + * + * Used by SCMI Protocols initialization code to register with the notification + * core the list of supported events and their descriptors: takes care to + * pre-allocate and store all needed descriptors, scratch buffers and event + * queues. + * + * Return: 0 on Success + */ +int scmi_register_protocol_events(const struct scmi_handle *handle, + u8 proto_id, size_t queue_sz, + const struct scmi_event_ops *ops, + const struct scmi_event *evt, int num_events, + int num_sources) +{ + int i; + size_t payld_sz = 0; + struct scmi_registered_events_desc *pd; + struct scmi_notify_instance *ni; + + if (!ops || !evt) + return -EINVAL; + + /* Ensure notify_priv is updated */ + smp_rmb(); + if (!handle->notify_priv) + return -ENOMEM; + ni = handle->notify_priv; + + /* Attach to the notification main devres group */ + if (!devres_open_group(ni->handle->dev, ni->gid, GFP_KERNEL)) + return -ENOMEM; + + for (i = 0; i < num_events; i++) + payld_sz = max_t(size_t, payld_sz, evt[i].max_payld_sz); + payld_sz += sizeof(struct scmi_event_header); + + pd = scmi_allocate_registered_events_desc(ni, proto_id, queue_sz, + payld_sz, num_events, ops); + if (IS_ERR(pd)) + goto err; + + for (i = 0; i < num_events; i++, evt++) { + struct scmi_registered_event *r_evt; + + r_evt = devm_kzalloc(ni->handle->dev, sizeof(*r_evt), + GFP_KERNEL); + if (!r_evt) + goto err; + r_evt->proto = pd; + r_evt->evt = evt; + + r_evt->sources = devm_kcalloc(ni->handle->dev, num_sources, + sizeof(refcount_t), GFP_KERNEL); + if (!r_evt->sources) + goto err; + r_evt->num_sources = num_sources; + mutex_init(&r_evt->sources_mtx); + + r_evt->report = devm_kzalloc(ni->handle->dev, + evt->max_report_sz, GFP_KERNEL); + if (!r_evt->report) + goto err; + + pd->registered_events[i] = r_evt; + /* Ensure events are updated */ + smp_wmb(); + dev_dbg(handle->dev, "registered event - %lX\n", + MAKE_ALL_SRCS_KEY(r_evt->proto->id, r_evt->evt->id)); + } + + /* Register protocol and events...it will never be removed */ + ni->registered_protocols[proto_id] = pd; + /* Ensure protocols are updated */ + smp_wmb(); + + devres_close_group(ni->handle->dev, ni->gid); + + return 0; + +err: + dev_warn(handle->dev, "Proto:%X - Registration Failed !\n", proto_id); + /* A failing protocol registration does not trigger full failure */ + devres_close_group(ni->handle->dev, ni->gid); + + return -ENOMEM; +} + +/** + * scmi_notification_init() - Initializes Notification Core Support + * @handle: The handle identifying the platform instance to initialize + * + * This function lays out all the basic resources needed by the notification + * core instance identified by the provided handle: once done, all of the + * SCMI Protocols can register their events with the core during their own + * initializations. + * + * Note that failing to initialize the core notifications support does not + * cause the whole SCMI Protocols stack to fail its initialization. + * + * SCMI Notification Initialization happens in 2 steps: + * * initialization: basic common allocations (this function) + * * registration: protocols asynchronously come into life and registers their + * own supported list of events with the core; this causes + * further per-protocol allocations + * + * Any user's callback registration attempt, referring a still not registered + * event, will be registered as pending and finalized later (if possible) + * by scmi_protocols_late_init() work. + * This allows for lazy initialization of SCMI Protocols due to late (or + * missing) SCMI drivers' modules loading. + * + * Return: 0 on Success + */ +int scmi_notification_init(struct scmi_handle *handle) +{ + void *gid; + struct scmi_notify_instance *ni; + + gid = devres_open_group(handle->dev, NULL, GFP_KERNEL); + if (!gid) + return -ENOMEM; + + ni = devm_kzalloc(handle->dev, sizeof(*ni), GFP_KERNEL); + if (!ni) + goto err; + + ni->gid = gid; + ni->handle = handle; + + ni->registered_protocols = devm_kcalloc(handle->dev, SCMI_MAX_PROTO, + sizeof(char *), GFP_KERNEL); + if (!ni->registered_protocols) + goto err; + + handle->notify_priv = ni; + /* Ensure handle is up to date */ + smp_wmb(); + + dev_info(handle->dev, "Core Enabled.\n"); + + devres_close_group(handle->dev, ni->gid); + + return 0; + +err: + dev_warn(handle->dev, "Initialization Failed.\n"); + devres_release_group(handle->dev, NULL); + return -ENOMEM; +} + +/** + * scmi_notification_exit() - Shutdown and clean Notification core + * @handle: The handle identifying the platform instance to shutdown + */ +void scmi_notification_exit(struct scmi_handle *handle) +{ + struct scmi_notify_instance *ni; + + /* Ensure notify_priv is updated */ + smp_rmb(); + if (!handle->notify_priv) + return; + ni = handle->notify_priv; + + devres_release_group(ni->handle->dev, ni->gid); +} diff --git a/drivers/firmware/arm_scmi/notify.h b/drivers/firmware/arm_scmi/notify.h new file mode 100644 index 000000000000..48702e42995f --- /dev/null +++ b/drivers/firmware/arm_scmi/notify.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * System Control and Management Interface (SCMI) Message Protocol + * notification header file containing some definitions, structures + * and function prototypes related to SCMI Notification handling. + * + * Copyright (C) 2020 ARM Ltd. + */ +#ifndef _SCMI_NOTIFY_H +#define _SCMI_NOTIFY_H + +#include +#include + +#define SCMI_PROTO_QUEUE_SZ 4096 + +/** + * struct scmi_event - Describes an event to be supported + * @id: Event ID + * @max_payld_sz: Max possible size for the payload of a notification message + * @max_report_sz: Max possible size for the report of a notification message + * + * Each SCMI protocol, during its initialization phase, can describe the events + * it wishes to support in a few struct scmi_event and pass them to the core + * using scmi_register_protocol_events(). + */ +struct scmi_event { + u8 id; + size_t max_payld_sz; + size_t max_report_sz; +}; + +/** + * struct scmi_event_ops - Protocol helpers called by the notification core. + * @set_notify_enabled: Enable/disable the required evt_id/src_id notifications + * using the proper custom protocol commands. + * Return 0 on Success + * + * Context: Helpers described in &struct scmi_event_ops are called only in + * process context. + */ +struct scmi_event_ops { + int (*set_notify_enabled)(const struct scmi_handle *handle, + u8 evt_id, u32 src_id, bool enabled); +}; + +int scmi_notification_init(struct scmi_handle *handle); +void scmi_notification_exit(struct scmi_handle *handle); + +int scmi_register_protocol_events(const struct scmi_handle *handle, + u8 proto_id, size_t queue_sz, + const struct scmi_event_ops *ops, + const struct scmi_event *evt, int num_events, + int num_sources); + +#endif /* _SCMI_NOTIFY_H */ diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h index 73911d156a39..9a34b02a9cce 100644 --- a/include/linux/scmi_protocol.h +++ b/include/linux/scmi_protocol.h @@ -233,6 +233,8 @@ struct scmi_reset_ops { * protocol(for internal use only) * @reset_priv: pointer to private data structure specific to reset * protocol(for internal use only) + * @notify_priv: pointer to private data structure specific to notifications + * (for internal use only) */ struct scmi_handle { struct device *dev; @@ -248,6 +250,7 @@ struct scmi_handle { void *power_priv; void *sensor_priv; void *reset_priv; + void *notify_priv; }; enum scmi_std_protocol { -- 2.11.0