drivers/net/caif/caif_shm_u5500.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Contact: Sjur Brendeland / sjur.brandeland@stericsson.com
   4  * Author:  Amarnath Revanna / amarnath.bangalore.revanna@stericsson.com
   5  * License terms: GNU General Public License (GPL) version 2
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ":" __func__ "():" fmt
   9
  10 #include <linux/version.h>
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/netdevice.h>
  14 #include <mach/mbox.h>
  15 #include <net/caif/caif_shm.h>
  16
  17 MODULE_LICENSE("GPL");
  18 MODULE_DESCRIPTION("CAIF Shared Memory protocol driver");
  19
  20 #define MAX_SHM_INSTANCES       1
  21
  22 enum {
  23         MBX_ACC0,
  24         MBX_ACC1,
  25         MBX_DSP
  26 };
  27
  28 static struct shmdev_layer shmdev_lyr[MAX_SHM_INSTANCES];
  29
  30 static unsigned int shm_start;
  31 static unsigned int shm_size;
  32
  33 module_param(shm_size, uint  , 0440);
  34 MODULE_PARM_DESC(shm_total_size, "Start of SHM shared memory");
  35
  36 module_param(shm_start, uint  , 0440);
  37 MODULE_PARM_DESC(shm_total_start, "Total Size of SHM shared memory");
  38
  39 static int shmdev_send_msg(u32 dev_id, u32 mbx_msg)
  40 {
  41         /* Always block until msg is written successfully */
  42         mbox_send(shmdev_lyr[dev_id].hmbx, mbx_msg, true);
  43         return 0;
  44 }
  45
  46 static int shmdev_mbx_setup(void *pshmdrv_cb, struct shmdev_layer *pshm_dev,
  47                                                          void *pshm_drv)
  48 {
  49         /*
  50          * For UX5500, we have only 1 SHM instance which uses MBX0
  51          * for communication with the peer modem
  52          */
  53         pshm_dev->hmbx = mbox_setup(MBX_ACC0, pshmdrv_cb, pshm_drv);
  54
  55         if (!pshm_dev->hmbx)
  56                 return -ENODEV;
  57         else
  58                 return 0;
  59 }
  60
  61 static int __init caif_shmdev_init(void)
  62 {
  63         int i, result;
  64
  65         /* Loop is currently overkill, there is only one instance */
  66         for (i = 0; i < MAX_SHM_INSTANCES; i++) {
  67
  68                 shmdev_lyr[i].shm_base_addr = shm_start;
  69                 shmdev_lyr[i].shm_total_sz = shm_size;
  70
  71                 if (((char *)shmdev_lyr[i].shm_base_addr == NULL)
  72                                || (shmdev_lyr[i].shm_total_sz <= 0))    {
  73                         pr_warn("ERROR,"
  74                                 "Shared memory Address and/or Size incorrect"
  75                                 ", Bailing out ...\n");
  76                         result = -EINVAL;
  77                         goto clean;
  78                 }
  79
  80                 pr_info("SHM AREA (instance %d) STARTS"
  81                         " AT %p\n", i, (char *)shmdev_lyr[i].shm_base_addr);
  82
  83                 shmdev_lyr[i].shm_id = i;
  84                 shmdev_lyr[i].pshmdev_mbxsend = shmdev_send_msg;
  85                 shmdev_lyr[i].pshmdev_mbxsetup = shmdev_mbx_setup;
  86
  87                 /*
  88                  * Finally, CAIF core module is called with details in place:
  89                  * 1. SHM base address
  90                  * 2. SHM size
  91                  * 3. MBX handle
  92                  */
  93                 result = caif_shmcore_probe(&shmdev_lyr[i]);
  94                 if (result) {
  95                         pr_warn("ERROR[%d],"
  96                                 "Could not probe SHM core (instance %d)"
  97                                 " Bailing out ...\n", result, i);
  98                         goto clean;
  99                 }
 100         }
 101
 102         return 0;
 103
 104 clean:
 105         /*
 106          * For now, we assume that even if one instance of SHM fails, we bail
 107          * out of the driver support completely. For this, we need to release
 108          * any memory allocated and unregister any instance of SHM net device.
 109          */
 110         for (i = 0; i < MAX_SHM_INSTANCES; i++) {
 111                 if (shmdev_lyr[i].pshm_netdev)
 112                         unregister_netdev(shmdev_lyr[i].pshm_netdev);
 113         }
 114         return result;
 115 }
 116
 117 static void __exit caif_shmdev_exit(void)
 118 {
 119         int i;
 120
 121         for (i = 0; i < MAX_SHM_INSTANCES; i++) {
 122                 caif_shmcore_remove(shmdev_lyr[i].pshm_netdev);
 123                 kfree((void *)shmdev_lyr[i].shm_base_addr);
 124         }
 125
 126 }
 127
 128 module_init(caif_shmdev_init);
 129 module_exit(caif_shmdev_exit);