caif-u5500: CAIF shared memory mailbox interface

/*

 * Copyright (C) ST-Ericsson AB 2010

 * Contact: Sjur Brendeland / sjur.brandeland@stericsson.com

 * Author:  Amarnath Revanna / amarnath.bangalore.revanna@stericsson.com

 * License terms: GNU General Public License (GPL) version 2

 */

#define pr_fmt(fmt) KBUILD_MODNAME ":" __func__ "():" fmt

#include <linux/version.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/netdevice.h>

#include <mach/mbox.h>

#include <net/caif/caif_shm.h>

MODULE_LICENSE("GPL");

MODULE_DESCRIPTION("CAIF Shared Memory protocol driver");

#define MAX_SHM_INSTANCES	1

enum {

	MBX_ACC0,

	MBX_ACC1,

	MBX_DSP

};

static struct shmdev_layer shmdev_lyr[MAX_SHM_INSTANCES];

static unsigned int shm_start;

static unsigned int shm_size;

module_param(shm_size, uint  , 0440);

MODULE_PARM_DESC(shm_total_size, "Start of SHM shared memory");

module_param(shm_start, uint  , 0440);

MODULE_PARM_DESC(shm_total_start, "Total Size of SHM shared memory");

static int shmdev_send_msg(u32 dev_id, u32 mbx_msg)

{

	/* Always block until msg is written successfully */

	mbox_send(shmdev_lyr[dev_id].hmbx, mbx_msg, true);

	return 0;

}

static int shmdev_mbx_setup(void *pshmdrv_cb, struct shmdev_layer *pshm_dev,

							 void *pshm_drv)

{

	/*

	 * For UX5500, we have only 1 SHM instance which uses MBX0

	 * for communication with the peer modem

	 */

	pshm_dev->hmbx = mbox_setup(MBX_ACC0, pshmdrv_cb, pshm_drv);

	if (!pshm_dev->hmbx)

		return -ENODEV;

	else

		return 0;

}

static int __init caif_shmdev_init(void)

{

	int i, result;

	/* Loop is currently overkill, there is only one instance */

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

		shmdev_lyr[i].shm_base_addr = shm_start;

		shmdev_lyr[i].shm_total_sz = shm_size;

		if (((char *)shmdev_lyr[i].shm_base_addr == NULL)

			       || (shmdev_lyr[i].shm_total_sz <= 0))	{

			pr_warn("ERROR,"

				"Shared memory Address and/or Size incorrect"

				", Bailing out ...\n");

			result = -EINVAL;

			goto clean;

		}

		pr_info("SHM AREA (instance %d) STARTS"

			" AT %p\n", i, (char *)shmdev_lyr[i].shm_base_addr);

		shmdev_lyr[i].shm_id = i;

		shmdev_lyr[i].pshmdev_mbxsend = shmdev_send_msg;

		shmdev_lyr[i].pshmdev_mbxsetup = shmdev_mbx_setup;

		/*

		 * Finally, CAIF core module is called with details in place:

		 * 1. SHM base address

		 * 2. SHM size

		 * 3. MBX handle

		 */

		result = caif_shmcore_probe(&shmdev_lyr[i]);

		if (result) {

			pr_warn("ERROR[%d],"

				"Could not probe SHM core (instance %d)"

				" Bailing out ...\n", result, i);

			goto clean;

		}

	}

	return 0;

clean:

	/*

	 * For now, we assume that even if one instance of SHM fails, we bail

	 * out of the driver support completely. For this, we need to release

	 * any memory allocated and unregister any instance of SHM net device.

	 */

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

		if (shmdev_lyr[i].pshm_netdev)

			unregister_netdev(shmdev_lyr[i].pshm_netdev);

	}

	return result;

}

static void __exit caif_shmdev_exit(void)

{

	int i;

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

		caif_shmcore_remove(shmdev_lyr[i].pshm_netdev);

		kfree((void *)shmdev_lyr[i].shm_base_addr);

	}

}

module_init(caif_shmdev_init);

module_exit(caif_shmdev_exit);