diff options
Diffstat (limited to 'drivers/firmware/arm_scmi/driver.c')
| -rw-r--r-- | drivers/firmware/arm_scmi/driver.c | 182 |
1 files changed, 180 insertions, 2 deletions
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 3e748e57deab..c1ec80e00734 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -11,11 +11,12 @@ * various power domain DVFS including the core/cluster, certain system * clocks configuration, thermal sensors and many others. * - * Copyright (C) 2018 ARM Ltd. + * Copyright (C) 2018-2021 ARM Ltd. */ #include <linux/bitmap.h> #include <linux/export.h> +#include <linux/idr.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/ktime.h> @@ -23,6 +24,7 @@ #include <linux/of_address.h> #include <linux/of_device.h> #include <linux/processor.h> +#include <linux/refcount.h> #include <linux/slab.h> #include "common.h" @@ -69,6 +71,21 @@ struct scmi_xfers_info { }; /** + * struct scmi_protocol_instance - Describe an initialized protocol instance. + * @proto: A reference to the protocol descriptor. + * @gid: A reference for per-protocol devres management. + * @users: A refcount to track effective users of this protocol. + * + * Each protocol is initialized independently once for each SCMI platform in + * which is defined by DT and implemented by the SCMI server fw. + */ +struct scmi_protocol_instance { + const struct scmi_protocol *proto; + void *gid; + refcount_t users; +}; + +/** * struct scmi_info - Structure representing a SCMI instance * * @dev: Device pointer @@ -80,6 +97,10 @@ struct scmi_xfers_info { * @rx_minfo: Universal Receive Message management info * @tx_idr: IDR object to map protocol id to Tx channel info pointer * @rx_idr: IDR object to map protocol id to Rx channel info pointer + * @protocols: IDR for protocols' instance descriptors initialized for + * this SCMI instance: populated on protocol's first attempted + * usage. + * @protocols_mtx: A mutex to protect protocols instances initialization. * @protocols_imp: List of protocols implemented, currently maximum of * MAX_PROTOCOLS_IMP elements allocated by the base protocol * @node: List head @@ -94,6 +115,9 @@ struct scmi_info { struct scmi_xfers_info rx_minfo; struct idr tx_idr; struct idr rx_idr; + struct idr protocols; + /* Ensure mutual exclusive access to protocols instance array */ + struct mutex protocols_mtx; u8 *protocols_imp; struct list_head node; int users; @@ -519,6 +543,150 @@ int scmi_version_get(const struct scmi_handle *handle, u8 protocol, return ret; } +/** + * scmi_alloc_init_protocol_instance - Allocate and initialize a protocol + * instance descriptor. + * @info: The reference to the related SCMI instance. + * @proto: The protocol descriptor. + * + * Allocate a new protocol instance descriptor, using the provided @proto + * description, against the specified SCMI instance @info, and initialize it; + * all resources management is handled via a dedicated per-protocol devres + * group. + * + * Context: Assumes to be called with @protocols_mtx already acquired. + * Return: A reference to a freshly allocated and initialized protocol instance + * or ERR_PTR on failure. + */ +static struct scmi_protocol_instance * +scmi_alloc_init_protocol_instance(struct scmi_info *info, + const struct scmi_protocol *proto) +{ + int ret = -ENOMEM; + void *gid; + struct scmi_protocol_instance *pi; + struct scmi_handle *handle = &info->handle; + + /* 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->instance_init(handle); + if (ret) + goto clean; + + ret = idr_alloc(&info->protocols, pi, proto->id, proto->id + 1, + GFP_KERNEL); + if (ret != proto->id) + goto clean; + + devres_close_group(handle->dev, pi->gid); + dev_dbg(handle->dev, "Initialized protocol: 0x%X\n", pi->proto->id); + + return pi; + +clean: + devres_release_group(handle->dev, gid); +out: + return ERR_PTR(ret); +} + +/** + * 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) +{ + struct scmi_protocol_instance *pi; + struct scmi_info *info = handle_to_scmi_info(handle); + + mutex_lock(&info->protocols_mtx); + pi = idr_find(&info->protocols, protocol_id); + + if (pi) { + refcount_inc(&pi->users); + } else { + const struct scmi_protocol *proto; + + /* Fails if protocol not registered on bus */ + proto = scmi_protocol_get(protocol_id); + if (proto) + pi = scmi_alloc_init_protocol_instance(info, proto); + else + pi = ERR_PTR(-ENODEV); + } + mutex_unlock(&info->protocols_mtx); + + return pi; +} + +/** + * scmi_protocol_acquire - 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_protocol_acquire(struct scmi_handle *handle, u8 protocol_id) +{ + return PTR_ERR_OR_ZERO(scmi_get_protocol_instance(handle, protocol_id)); +} + +/** + * scmi_protocol_release - 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_protocol_release(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); + pi = idr_find(&info->protocols, protocol_id); + if (WARN_ON(!pi)) + goto out; + + if (refcount_dec_and_test(&pi->users)) { + void *gid = pi->gid; + + if (pi->proto->instance_deinit) + pi->proto->instance_deinit(handle); + + idr_remove(&info->protocols, protocol_id); + + devres_release_group(handle->dev, gid); + dev_dbg(handle->dev, "De-Initialized protocol: 0x%X\n", + protocol_id); + } + +out: + mutex_unlock(&info->protocols_mtx); +} + void scmi_setup_protocol_implemented(const struct scmi_handle *handle, u8 *prot_imp) { @@ -786,6 +954,8 @@ static int scmi_probe(struct platform_device *pdev) info->dev = dev; info->desc = desc; INIT_LIST_HEAD(&info->node); + idr_init(&info->protocols); + mutex_init(&info->protocols_mtx); platform_set_drvdata(pdev, info); idr_init(&info->tx_idr); @@ -860,6 +1030,10 @@ static int scmi_remove(struct platform_device *pdev) scmi_notification_exit(&info->handle); + mutex_lock(&info->protocols_mtx); + idr_destroy(&info->protocols); + mutex_unlock(&info->protocols_mtx); + /* Safe to free channels since no more users */ ret = idr_for_each(idr, info->desc->ops->chan_free, idr); idr_destroy(&info->tx_idr); @@ -942,6 +1116,8 @@ static int __init scmi_driver_init(void) { scmi_bus_init(); + scmi_base_register(); + scmi_clock_register(); scmi_perf_register(); scmi_power_register(); @@ -956,7 +1132,7 @@ subsys_initcall(scmi_driver_init); static void __exit scmi_driver_exit(void) { - scmi_bus_exit(); + scmi_base_unregister(); scmi_clock_unregister(); scmi_perf_unregister(); @@ -966,6 +1142,8 @@ static void __exit scmi_driver_exit(void) scmi_voltage_unregister(); scmi_system_unregister(); + scmi_bus_exit(); + platform_driver_unregister(&scmi_driver); } module_exit(scmi_driver_exit); |