caif_shm_u5500.c

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/*
 * Copyright (C) ST-Ericsson AB 2010
 * Contact: Sjur Brendeland / [email protected]
 * Author:  Amarnath Revanna / [email protected]
 * License terms: GNU General Public License (GPL) version 2
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":" fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <mach/mbox-db5500.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);