Messages in this thread | | | Date | Thu, 15 Oct 2020 10:58:30 +0100 | From | Cristian Marussi <> | Subject | Re: [PATCH 01/11] firmware: arm_scmi: review protocol registration interface |
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Hi Vincent,
thanks for the review.
On Thu, Oct 15, 2020 at 11:41:09AM +0200, Vincent Guittot wrote: > 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 ? >
You're right, it's a leftover I think, since initially there was no mutex. I'll remove it in V2.
Thanks
Cristian
> > + 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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