Messages in this thread | | | From | Vincent Guittot <> | Date | Thu, 15 Oct 2020 11:41:09 +0200 | Subject | Re: [PATCH 01/11] firmware: arm_scmi: review protocol registration interface |
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On Wed, 14 Oct 2020 at 17:06, Cristian Marussi <cristian.marussi@arm.com> wrote: > > Extend common protocol registration routines and provide some new generic > protocols' init/deinit helpers that tracks protocols' users and automatically > perform the proper initialization/de-initialization on demand. > > Convert all protocols to use new registration schema while modifying only Base > protocol to use also the new initialization helpers. > > All other standard protocols' initialization is still umodified and bound to > SCMI devices probing. > > Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> > ---
[...]
> > +/** > + * scmi_get_protocol_instance - Protocol initialization helper. > + * @handle: A reference to the SCMI platform instance. > + * @protocol_id: The protocol being requested. > + * > + * In case the required protocol has never been requested before for this > + * instance, allocate and initialize all the needed structures while handling > + * resource allocation with a dedicated per-protocol devres subgroup. > + * > + * Return: A reference to an initialized protocol instance or error on failure. > + */ > +static struct scmi_protocol_instance * __must_check > +scmi_get_protocol_instance(struct scmi_handle *handle, u8 protocol_id) > +{ > + int ret = -ENOMEM; > + void *gid; > + struct scmi_protocol_instance *pi; > + struct scmi_info *info = handle_to_scmi_info(handle); > + > + mutex_lock(&info->protocols_mtx); > + /* Ensure protocols has been updated */ > + smp_rmb();
Why do you need this smp_rmb and the smp_wmb below ?
Isn't the mutex not enough ?
> + pi = info->protocols[protocol_id]; > + > + if (!pi) { > + const struct scmi_protocol *proto; > + > + /* Fail if protocol not registered on bus */ > + proto = scmi_get_protocol(protocol_id); > + if (!proto) { > + ret = -EINVAL; > + goto out; > + } > + > + /* Protocol specific devres group */ > + gid = devres_open_group(handle->dev, NULL, GFP_KERNEL); > + if (!gid) > + goto out; > + > + pi = devm_kzalloc(handle->dev, sizeof(*pi), GFP_KERNEL); > + if (!pi) > + goto clean; > + > + pi->gid = gid; > + pi->proto = proto; > + refcount_set(&pi->users, 1); > + /* proto->init is assured NON NULL by scmi_protocol_register */ > + ret = pi->proto->init(handle); > + if (ret) > + goto clean; > + > + info->protocols[protocol_id] = pi; > + /* Ensure initialized protocol is visible */ > + smp_wmb(); > + > + devres_close_group(handle->dev, pi->gid); > + dev_dbg(handle->dev, "Initialized protocol: 0x%X\n", > + protocol_id); > + } else { > + refcount_inc(&pi->users); > + } > + mutex_unlock(&info->protocols_mtx); > + > + return pi; > + > +clean: > + devres_release_group(handle->dev, gid); > +out: > + mutex_unlock(&info->protocols_mtx); > + return ERR_PTR(ret); > +} > + > +/** > + * scmi_acquire_protocol - Protocol acquire > + * @handle: A reference to the SCMI platform instance. > + * @protocol_id: The protocol being requested. > + * > + * Register a new user for the requested protocol on the specified SCMI > + * platform instance, possibly triggering its initialization on first user. > + * > + * Return: 0 if protocol was acquired successfully. > + */ > +int scmi_acquire_protocol(struct scmi_handle *handle, u8 protocol_id) > +{ > + return IS_ERR(scmi_get_protocol_instance(handle, protocol_id)); > +} > + > +/** > + * scmi_release_protocol - Protocol de-initialization helper. > + * @handle: A reference to the SCMI platform instance. > + * @protocol_id: The protocol being requested. > + * > + * Remove one user for the specified protocol and triggers de-initialization > + * and resources de-allocation once the last user has gone. > + */ > +void scmi_release_protocol(struct scmi_handle *handle, u8 protocol_id) > +{ > + struct scmi_info *info = handle_to_scmi_info(handle); > + struct scmi_protocol_instance *pi; > + > + mutex_lock(&info->protocols_mtx); > + /* Ensure protocols has been updated */ > + smp_rmb(); > + pi = info->protocols[protocol_id]; > + if (WARN_ON(!pi)) { > + mutex_unlock(&info->protocols_mtx); > + return; > + } > + > + if (refcount_dec_and_test(&pi->users)) { > + void *gid = pi->gid; > + > + if (pi->proto->deinit) > + pi->proto->deinit(handle); > + > + info->protocols[protocol_id] = NULL; > + /* Ensure deinitialized protocol is visible */ > + smp_wmb(); > + > + devres_release_group(handle->dev, gid); > + dev_dbg(handle->dev, "De-Initialized protocol: 0x%X\n", > + protocol_id); > + } > + mutex_unlock(&info->protocols_mtx); > +} > + > void scmi_setup_protocol_implemented(const struct scmi_handle *handle, > u8 *prot_imp) > { > @@ -785,6 +934,7 @@ static int scmi_probe(struct platform_device *pdev) > info->dev = dev; > info->desc = desc; > INIT_LIST_HEAD(&info->node); > + mutex_init(&info->protocols_mtx); > > platform_set_drvdata(pdev, info); > idr_init(&info->tx_idr); > @@ -805,10 +955,14 @@ static int scmi_probe(struct platform_device *pdev) > if (scmi_notification_init(handle)) > dev_err(dev, "SCMI Notifications NOT available.\n"); > > - ret = scmi_base_protocol_init(handle); > - if (ret) { > - dev_err(dev, "unable to communicate with SCMI(%d)\n", ret); > - return ret; > + /* > + * Trigger SCMI Base protocol initialization. > + * It's mandatory and won't be ever released/deinit until the > + * SCMI stack is shutdown/unloaded as a whole. > + */ > + if (scmi_acquire_protocol(handle, SCMI_PROTOCOL_BASE)) { > + dev_err(dev, "unable to communicate with SCMI\n"); > + return -ENODEV; > } > > mutex_lock(&scmi_list_mutex); > @@ -941,6 +1095,8 @@ static int __init scmi_driver_init(void) > { > scmi_bus_init(); > > + scmi_base_register(); > + > scmi_clock_register(); > scmi_perf_register(); > scmi_power_register(); > @@ -954,7 +1110,7 @@ subsys_initcall(scmi_driver_init); > > static void __exit scmi_driver_exit(void) > { > - scmi_bus_exit(); > + scmi_base_unregister(); > > scmi_clock_unregister(); > scmi_perf_unregister(); > @@ -963,6 +1119,8 @@ static void __exit scmi_driver_exit(void) > scmi_sensors_unregister(); > scmi_system_unregister(); > > + scmi_bus_exit(); > + > platform_driver_unregister(&scmi_driver); > } > module_exit(scmi_driver_exit); > diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c > index c24e427dce0d..eae58b2a92cc 100644 > --- a/drivers/firmware/arm_scmi/notify.c > +++ b/drivers/firmware/arm_scmi/notify.c > @@ -91,10 +91,9 @@ > #include <linux/types.h> > #include <linux/workqueue.h> > > +#include "common.h" > #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) > diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c > index 82fb3babff72..854460a051c2 100644 > --- a/drivers/firmware/arm_scmi/perf.c > +++ b/drivers/firmware/arm_scmi/perf.c > @@ -2,7 +2,7 @@ > /* > * System Control and Management Interface (SCMI) Performance Protocol > * > - * Copyright (C) 2018 ARM Ltd. > + * Copyright (C) 2018-2020 ARM Ltd. > */ > > #define pr_fmt(fmt) "SCMI Notifications PERF - " fmt > @@ -892,4 +892,10 @@ static int scmi_perf_protocol_init(struct scmi_handle *handle) > return 0; > } > > -DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(SCMI_PROTOCOL_PERF, perf) > +static struct scmi_protocol scmi_perf = { > + .id = SCMI_PROTOCOL_PERF, > + .init = &scmi_perf_protocol_init, > + .ops = &perf_ops, > +}; > + > +DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(perf, scmi_perf) > diff --git a/drivers/firmware/arm_scmi/power.c b/drivers/firmware/arm_scmi/power.c > index 1f37258e9bee..42c9c88da07c 100644 > --- a/drivers/firmware/arm_scmi/power.c > +++ b/drivers/firmware/arm_scmi/power.c > @@ -2,7 +2,7 @@ > /* > * System Control and Management Interface (SCMI) Power Protocol > * > - * Copyright (C) 2018 ARM Ltd. > + * Copyright (C) 2018-2020 ARM Ltd. > */ > > #define pr_fmt(fmt) "SCMI Notifications POWER - " fmt > @@ -301,4 +301,10 @@ static int scmi_power_protocol_init(struct scmi_handle *handle) > return 0; > } > > -DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(SCMI_PROTOCOL_POWER, power) > +static struct scmi_protocol scmi_power = { > + .id = SCMI_PROTOCOL_POWER, > + .init = &scmi_power_protocol_init, > + .ops = &power_ops, > +}; > + > +DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(power, scmi_power) > diff --git a/drivers/firmware/arm_scmi/reset.c b/drivers/firmware/arm_scmi/reset.c > index a981a22cfe89..2caf0bdb6fdc 100644 > --- a/drivers/firmware/arm_scmi/reset.c > +++ b/drivers/firmware/arm_scmi/reset.c > @@ -2,7 +2,7 @@ > /* > * System Control and Management Interface (SCMI) Reset Protocol > * > - * Copyright (C) 2019 ARM Ltd. > + * Copyright (C) 2019-2020 ARM Ltd. > */ > > #define pr_fmt(fmt) "SCMI Notifications RESET - " fmt > @@ -311,4 +311,10 @@ static int scmi_reset_protocol_init(struct scmi_handle *handle) > return 0; > } > > -DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(SCMI_PROTOCOL_RESET, reset) > +static struct scmi_protocol scmi_reset = { > + .id = SCMI_PROTOCOL_RESET, > + .init = &scmi_reset_protocol_init, > + .ops = &reset_ops, > +}; > + > +DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(reset, scmi_reset) > diff --git a/drivers/firmware/arm_scmi/sensors.c b/drivers/firmware/arm_scmi/sensors.c > index b4232d611033..dfe3076d2093 100644 > --- a/drivers/firmware/arm_scmi/sensors.c > +++ b/drivers/firmware/arm_scmi/sensors.c > @@ -2,7 +2,7 @@ > /* > * System Control and Management Interface (SCMI) Sensor Protocol > * > - * Copyright (C) 2018 ARM Ltd. > + * Copyright (C) 2018-2020 ARM Ltd. > */ > > #define pr_fmt(fmt) "SCMI Notifications SENSOR - " fmt > @@ -367,4 +367,10 @@ static int scmi_sensors_protocol_init(struct scmi_handle *handle) > return 0; > } > > -DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(SCMI_PROTOCOL_SENSOR, sensors) > +static struct scmi_protocol scmi_sensors = { > + .id = SCMI_PROTOCOL_SENSOR, > + .init = &scmi_sensors_protocol_init, > + .ops = &sensor_ops, > +}; > + > +DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(sensors, scmi_sensors) > diff --git a/drivers/firmware/arm_scmi/system.c b/drivers/firmware/arm_scmi/system.c > index 283e12d5f24b..bcea18bf54ab 100644 > --- a/drivers/firmware/arm_scmi/system.c > +++ b/drivers/firmware/arm_scmi/system.c > @@ -128,4 +128,10 @@ static int scmi_system_protocol_init(struct scmi_handle *handle) > return 0; > } > > -DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(SCMI_PROTOCOL_SYSTEM, system) > +static struct scmi_protocol scmi_system = { > + .id = SCMI_PROTOCOL_SYSTEM, > + .init = &scmi_system_protocol_init, > + .ops = NULL, > +}; > + > +DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(system, scmi_system) > diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h > index 9cd312a1ff92..ca23d682941e 100644 > --- a/include/linux/scmi_protocol.h > +++ b/include/linux/scmi_protocol.h > @@ -376,9 +376,9 @@ static inline void scmi_driver_unregister(struct scmi_driver *driver) {} > #define module_scmi_driver(__scmi_driver) \ > module_driver(__scmi_driver, scmi_register, scmi_unregister) > > -typedef int (*scmi_prot_init_fn_t)(struct scmi_handle *); > -int scmi_protocol_register(int protocol_id, scmi_prot_init_fn_t fn); > -void scmi_protocol_unregister(int protocol_id); > +struct scmi_protocol; > +int scmi_protocol_register(struct scmi_protocol *proto); > +void scmi_protocol_unregister(const struct scmi_protocol *proto); > > /* SCMI Notification API - Custom Event Reports */ > enum scmi_notification_events { > -- > 2.17.1 >
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