kernel-ark/drivers/hsi/hsi.c
Carlos Chinea ec1c56ff81 HSI: hsi: Rework hsi_event interface
Remove custom hack and make use of the notifier chain interfaces for
delivering events from the ports to their associated clients.
Clients that want to receive port events need to register their callbacks
using hsi_register_port_event(). The callbacks can be called in interrupt
context. Use hsi_unregestier_port_event() to undo the registration.

Signed-off-by: Carlos Chinea <carlos.chinea@nokia.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
2012-04-23 14:23:32 +03:00

508 lines
12 KiB
C

/*
* 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");