/*
* 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
* @cb: 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");
