Commit a056ab8c authored by Carlos Chinea's avatar Carlos Chinea
Browse files

HSI: hsi: Introducing HSI framework 



Adds HSI framework in to the linux kernel.

High Speed Synchronous Serial Interface (HSI) is a
serial interface mainly used for connecting application
engines (APE) with cellular modem engines (CMT) in cellular
handsets.

HSI provides multiplexing for up to 16 logical channels,
low-latency and full duplex communication.

Signed-off-by: default avatarCarlos Chinea <carlos.chinea@nokia.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 805a6af8

drivers/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -52,6 +52,8 @@ source "drivers/i2c/Kconfig" 


source "drivers/spi/Kconfig"



source "drivers/hsi/Kconfig"



source "drivers/pps/Kconfig"



source "drivers/ptp/Kconfig"

drivers/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ obj-$(CONFIG_ATA) += ata/ 
obj-$(CONFIG_TARGET_CORE)	+= target/

obj-$(CONFIG_MTD)		+= mtd/

obj-$(CONFIG_SPI)		+= spi/

obj-y				+= hsi/

obj-y				+= net/

obj-$(CONFIG_ATM)		+= atm/

obj-$(CONFIG_FUSION)		+= message/

drivers/hsi/Kconfig

0 → 100644
+17 −0
Original line number Diff line number Diff line 
#

# HSI driver configuration

#

menuconfig HSI

	tristate "HSI support"

	---help---

	  The "High speed synchronous Serial Interface" is

	  synchronous serial interface used mainly to connect

	  application engines and cellular modems.



if HSI



config HSI_BOARDINFO

	bool

	default y



endif # HSI

drivers/hsi/Makefile

0 → 100644
+5 −0
Original line number Diff line number Diff line 
#

# Makefile for HSI

#

obj-$(CONFIG_HSI_BOARDINFO)	+= hsi_boardinfo.o

obj-$(CONFIG_HSI)		+= hsi.o

drivers/hsi/hsi.c

0 → 100644
+494 −0
Original line number Diff line number Diff line 
/*

 * 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/rwsem.h>

#include <linux/list.h>

#include <linux/spinlock.h>

#include <linux/kobject.h>

#include <linux/slab.h>

#include <linux/string.h>

#include "hsi_core.h"



static struct device_type hsi_ctrl = {

	.name	= "hsi_controller",

};



static struct device_type hsi_cl = {

	.name	= "hsi_client",

};



static struct device_type hsi_port = {

	.name	= "hsi_port",

};



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)

{

	if (dev->type == &hsi_cl)

		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;

	unsigned long flags;



	cl = kzalloc(sizeof(*cl), GFP_KERNEL);

	if (!cl)

		return;

	cl->device.type = &hsi_cl;

	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;

	spin_lock_irqsave(&port->clock, flags);

	list_add_tail(&cl->link, &port->clients);

	spin_unlock_irqrestore(&port->clock, flags);

	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);

		kfree(cl);

	}

}



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)

{

	struct hsi_client *cl = to_hsi_client(dev);

	struct hsi_port *port = to_hsi_port(dev->parent);

	unsigned long flags;



	spin_lock_irqsave(&port->clock, flags);

	list_del(&cl->link);

	spin_unlock_irqrestore(&port->clock, flags);

	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 __maybe_unused)

{

}



static void hsi_port_release(struct device *dev __maybe_unused)

{

}



/**

 * 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;



	hsi->device.type = &hsi_ctrl;

	hsi->device.bus = &hsi_bus_type;

	hsi->device.release = hsi_controller_release;

	err = device_register(&hsi->device);

	if (err < 0)

		return err;

	for (i = 0; i < hsi->num_ports; i++) {

		hsi->port[i].device.parent = &hsi->device;

		hsi->port[i].device.bus = &hsi_bus_type;

		hsi->port[i].device.release = hsi_port_release;

		hsi->port[i].device.type = &hsi_port;

		INIT_LIST_HEAD(&hsi->port[i].clients);

		spin_lock_init(&hsi->port[i].clock);

		err = device_register(&hsi->port[i].device);

		if (err < 0)

			goto out;

	}

	/* Populate HSI bus with HSI clients */

	hsi_scan_board_info(hsi);



	return 0;

out:

	hsi_unregister_controller(hsi);



	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_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;



	port = kzalloc(sizeof(*port)*n_ports, flags);

	if (!port)

		return NULL;

	hsi = kzalloc(sizeof(*hsi), flags);

	if (!hsi)

		goto out;

	for (i = 0; i < n_ports; i++) {

		dev_set_name(&port[i].device, "port%d", i);

		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);

	}

	hsi->num_ports = n_ports;

	hsi->port = port;



	return hsi;

out:

	kfree(port);



	return NULL;

}

EXPORT_SYMBOL_GPL(hsi_alloc_controller);



/**

 * hsi_free_controller - Free an HSI controller

 * @hsi: Pointer to HSI controller

 */

void hsi_free_controller(struct hsi_controller *hsi)

{

	if (!hsi)

		return;



	kfree(hsi->port);

	kfree(hsi);

}

EXPORT_SYMBOL_GPL(hsi_free_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_start_rx(struct hsi_client *cl, void *data __maybe_unused)

{

	if (cl->hsi_start_rx)

		(*cl->hsi_start_rx)(cl);



	return 0;

}



static int hsi_stop_rx(struct hsi_client *cl, void *data __maybe_unused)

{

	if (cl->hsi_stop_rx)

		(*cl->hsi_stop_rx)(cl);



	return 0;

}



static int hsi_port_for_each_client(struct hsi_port *port, void *data,

				int (*fn)(struct hsi_client *cl, void *data))

{

	struct hsi_client *cl;



	spin_lock(&port->clock);

	list_for_each_entry(cl, &port->clients, link) {

		spin_unlock(&port->clock);

		(*fn)(cl, data);

		spin_lock(&port->clock);

	}

	spin_unlock(&port->clock);



	return 0;

}



/**

 * 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

 */

void hsi_event(struct hsi_port *port, unsigned int event)

{

	int (*fn)(struct hsi_client *cl, void *data);



	switch (event) {

	case HSI_EVENT_START_RX:

		fn = hsi_start_rx;

		break;

	case HSI_EVENT_STOP_RX:

		fn = hsi_stop_rx;

		break;

	default:

		return;

	}

	hsi_port_for_each_client(port, NULL, fn);

}

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");

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