/* * HSI core. * * Copyright (C) 2010 Nokia Corporation. All rights reserved. * * Contact: Carlos Chinea <carlos.chinea@nokia.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * version 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA */ #include <linux/hsi/hsi.h> #include <linux/compiler.h> #include <linux/list.h> #include <linux/kobject.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/notifier.h> #include "hsi_core.h" static ssize_t modalias_show(struct device *dev, struct device_attribute *a __maybe_unused, char *buf) { return sprintf(buf, "hsi:%s\n", dev_name(dev)); } static struct device_attribute hsi_bus_dev_attrs[] = { __ATTR_RO(modalias), __ATTR_NULL, }; static int hsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env) { add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev)); return 0; } static int hsi_bus_match(struct device *dev, struct device_driver *driver) { return strcmp(dev_name(dev), driver->name) == 0; } static struct bus_type hsi_bus_type = { .name = "hsi", .dev_attrs = hsi_bus_dev_attrs, .match = hsi_bus_match, .uevent = hsi_bus_uevent, }; static void hsi_client_release(struct device *dev) { kfree(to_hsi_client(dev)); } static void hsi_new_client(struct hsi_port *port, struct hsi_board_info *info) { struct hsi_client *cl; cl = kzalloc(sizeof(*cl), GFP_KERNEL); if (!cl) return; cl->tx_cfg = info->tx_cfg; cl->rx_cfg = info->rx_cfg; cl->device.bus = &hsi_bus_type; cl->device.parent = &port->device; cl->device.release = hsi_client_release; dev_set_name(&cl->device, info->name); cl->device.platform_data = info->platform_data; if (info->archdata) cl->device.archdata = *info->archdata; if (device_register(&cl->device) < 0) { pr_err("hsi: failed to register client: %s\n", info->name); put_device(&cl->device); } } static void hsi_scan_board_info(struct hsi_controller *hsi) { struct hsi_cl_info *cl_info; struct hsi_port *p; list_for_each_entry(cl_info, &hsi_board_list, list) if (cl_info->info.hsi_id == hsi->id) { p = hsi_find_port_num(hsi, cl_info->info.port); if (!p) continue; hsi_new_client(p, &cl_info->info); } } static int hsi_remove_client(struct device *dev, void *data __maybe_unused) { device_unregister(dev); return 0; } static int hsi_remove_port(struct device *dev, void *data __maybe_unused) { device_for_each_child(dev, NULL, hsi_remove_client); device_unregister(dev); return 0; } static void hsi_controller_release(struct device *dev) { struct hsi_controller *hsi = to_hsi_controller(dev); kfree(hsi->port); kfree(hsi); } static void hsi_port_release(struct device *dev) { kfree(to_hsi_port(dev)); } /** * hsi_unregister_controller - Unregister an HSI controller * @hsi: The HSI controller to register */ void hsi_unregister_controller(struct hsi_controller *hsi) { device_for_each_child(&hsi->device, NULL, hsi_remove_port); device_unregister(&hsi->device); } EXPORT_SYMBOL_GPL(hsi_unregister_controller); /** * hsi_register_controller - Register an HSI controller and its ports * @hsi: The HSI controller to register * * Returns -errno on failure, 0 on success. */ int hsi_register_controller(struct hsi_controller *hsi) { unsigned int i; int err; err = device_add(&hsi->device); if (err < 0) return err; for (i = 0; i < hsi->num_ports; i++) { hsi->port[i]->device.parent = &hsi->device; err = device_add(&hsi->port[i]->device); if (err < 0) goto out; } /* Populate HSI bus with HSI clients */ hsi_scan_board_info(hsi); return 0; out: while (i-- > 0) device_del(&hsi->port[i]->device); device_del(&hsi->device); return err; } EXPORT_SYMBOL_GPL(hsi_register_controller); /** * hsi_register_client_driver - Register an HSI client to the HSI bus * @drv: HSI client driver to register * * Returns -errno on failure, 0 on success. */ int hsi_register_client_driver(struct hsi_client_driver *drv) { drv->driver.bus = &hsi_bus_type; return driver_register(&drv->driver); } EXPORT_SYMBOL_GPL(hsi_register_client_driver); static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused) { return 0; } static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused) { return 0; } /** * hsi_put_controller - Free an HSI controller * * @hsi: Pointer to the HSI controller to freed * * HSI controller drivers should only use this function if they need * to free their allocated hsi_controller structures before a successful * call to hsi_register_controller. Other use is not allowed. */ void hsi_put_controller(struct hsi_controller *hsi) { unsigned int i; if (!hsi) return; for (i = 0; i < hsi->num_ports; i++) if (hsi->port && hsi->port[i]) put_device(&hsi->port[i]->device); put_device(&hsi->device); } EXPORT_SYMBOL_GPL(hsi_put_controller); /** * hsi_alloc_controller - Allocate an HSI controller and its ports * @n_ports: Number of ports on the HSI controller * @flags: Kernel allocation flags * * Return NULL on failure or a pointer to an hsi_controller on success. */ struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags) { struct hsi_controller *hsi; struct hsi_port **port; unsigned int i; if (!n_ports) return NULL; hsi = kzalloc(sizeof(*hsi), flags); if (!hsi) return NULL; port = kzalloc(sizeof(*port)*n_ports, flags); if (!port) { kfree(hsi); return NULL; } hsi->num_ports = n_ports; hsi->port = port; hsi->device.release = hsi_controller_release; device_initialize(&hsi->device); for (i = 0; i < n_ports; i++) { port[i] = kzalloc(sizeof(**port), flags); if (port[i] == NULL) goto out; port[i]->num = i; port[i]->async = hsi_dummy_msg; port[i]->setup = hsi_dummy_cl; port[i]->flush = hsi_dummy_cl; port[i]->start_tx = hsi_dummy_cl; port[i]->stop_tx = hsi_dummy_cl; port[i]->release = hsi_dummy_cl; mutex_init(&port[i]->lock); ATOMIC_INIT_NOTIFIER_HEAD(&port[i]->n_head); dev_set_name(&port[i]->device, "port%d", i); hsi->port[i]->device.release = hsi_port_release; device_initialize(&hsi->port[i]->device); } return hsi; out: hsi_put_controller(hsi); return NULL; } EXPORT_SYMBOL_GPL(hsi_alloc_controller); /** * hsi_free_msg - Free an HSI message * @msg: Pointer to the HSI message * * Client is responsible to free the buffers pointed by the scatterlists. */ void hsi_free_msg(struct hsi_msg *msg) { if (!msg) return; sg_free_table(&msg->sgt); kfree(msg); } EXPORT_SYMBOL_GPL(hsi_free_msg); /** * hsi_alloc_msg - Allocate an HSI message * @nents: Number of memory entries * @flags: Kernel allocation flags * * nents can be 0. This mainly makes sense for read transfer. * In that case, HSI drivers will call the complete callback when * there is data to be read without consuming it. * * Return NULL on failure or a pointer to an hsi_msg on success. */ struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags) { struct hsi_msg *msg; int err; msg = kzalloc(sizeof(*msg), flags); if (!msg) return NULL; if (!nents) return msg; err = sg_alloc_table(&msg->sgt, nents, flags); if (unlikely(err)) { kfree(msg); msg = NULL; } return msg; } EXPORT_SYMBOL_GPL(hsi_alloc_msg); /** * hsi_async - Submit an HSI transfer to the controller * @cl: HSI client sending the transfer * @msg: The HSI transfer passed to controller * * The HSI message must have the channel, ttype, complete and destructor * fields set beforehand. If nents > 0 then the client has to initialize * also the scatterlists to point to the buffers to write to or read from. * * HSI controllers relay on pre-allocated buffers from their clients and they * do not allocate buffers on their own. * * Once the HSI message transfer finishes, the HSI controller calls the * complete callback with the status and actual_len fields of the HSI message * updated. The complete callback can be called before returning from * hsi_async. * * Returns -errno on failure or 0 on success */ int hsi_async(struct hsi_client *cl, struct hsi_msg *msg) { struct hsi_port *port = hsi_get_port(cl); if (!hsi_port_claimed(cl)) return -EACCES; WARN_ON_ONCE(!msg->destructor || !msg->complete); msg->cl = cl; return port->async(msg); } EXPORT_SYMBOL_GPL(hsi_async); /** * hsi_claim_port - Claim the HSI client's port * @cl: HSI client that wants to claim its port * @share: Flag to indicate if the client wants to share the port or not. * * Returns -errno on failure, 0 on success. */ int hsi_claim_port(struct hsi_client *cl, unsigned int share) { struct hsi_port *port = hsi_get_port(cl); int err = 0; mutex_lock(&port->lock); if ((port->claimed) && (!port->shared || !share)) { err = -EBUSY; goto out; } if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) { err = -ENODEV; goto out; } port->claimed++; port->shared = !!share; cl->pclaimed = 1; out: mutex_unlock(&port->lock); return err; } EXPORT_SYMBOL_GPL(hsi_claim_port); /** * hsi_release_port - Release the HSI client's port * @cl: HSI client which previously claimed its port */ void hsi_release_port(struct hsi_client *cl) { struct hsi_port *port = hsi_get_port(cl); mutex_lock(&port->lock); /* Allow HW driver to do some cleanup */ port->release(cl); if (cl->pclaimed) port->claimed--; BUG_ON(port->claimed < 0); cl->pclaimed = 0; if (!port->claimed) port->shared = 0; module_put(to_hsi_controller(port->device.parent)->owner); mutex_unlock(&port->lock); } EXPORT_SYMBOL_GPL(hsi_release_port); static int hsi_event_notifier_call(struct notifier_block *nb, unsigned long event, void *data __maybe_unused) { struct hsi_client *cl = container_of(nb, struct hsi_client, nb); (*cl->ehandler)(cl, event); return 0; } /** * hsi_register_port_event - Register a client to receive port events * @cl: HSI client that wants to receive port events * @handler: Event handler callback * * Clients should register a callback to be able to receive * events from the ports. Registration should happen after * claiming the port. * The handler can be called in interrupt context. * * Returns -errno on error, or 0 on success. */ int hsi_register_port_event(struct hsi_client *cl, void (*handler)(struct hsi_client *, unsigned long)) { struct hsi_port *port = hsi_get_port(cl); if (!handler || cl->ehandler) return -EINVAL; if (!hsi_port_claimed(cl)) return -EACCES; cl->ehandler = handler; cl->nb.notifier_call = hsi_event_notifier_call; return atomic_notifier_chain_register(&port->n_head, &cl->nb); } EXPORT_SYMBOL_GPL(hsi_register_port_event); /** * hsi_unregister_port_event - Stop receiving port events for a client * @cl: HSI client that wants to stop receiving port events * * Clients should call this function before releasing their associated * port. * * Returns -errno on error, or 0 on success. */ int hsi_unregister_port_event(struct hsi_client *cl) { struct hsi_port *port = hsi_get_port(cl); int err; WARN_ON(!hsi_port_claimed(cl)); err = atomic_notifier_chain_unregister(&port->n_head, &cl->nb); if (!err) cl->ehandler = NULL; return err; } EXPORT_SYMBOL_GPL(hsi_unregister_port_event); /** * hsi_event -Notifies clients about port events * @port: Port where the event occurred * @event: The event type * * Clients should not be concerned about wake line behavior. However, due * to a race condition in HSI HW protocol, clients need to be notified * about wake line changes, so they can implement a workaround for it. * * Events: * HSI_EVENT_START_RX - Incoming wake line high * HSI_EVENT_STOP_RX - Incoming wake line down * * Returns -errno on error, or 0 on success. */ int hsi_event(struct hsi_port *port, unsigned long event) { return atomic_notifier_call_chain(&port->n_head, event, NULL); } EXPORT_SYMBOL_GPL(hsi_event); static int __init hsi_init(void) { return bus_register(&hsi_bus_type); } postcore_initcall(hsi_init); static void __exit hsi_exit(void) { bus_unregister(&hsi_bus_type); } module_exit(hsi_exit); MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>"); MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework"); MODULE_LICENSE("GPL v2");