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 ":" fmt
   9
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/netdevice.h>
  13 #include <mach/mbox-db5500.h>
  14 #include <net/caif/caif_shm.h>
  15
  16 MODULE_LICENSE("GPL");
  17 MODULE_DESCRIPTION("CAIF Shared Memory protocol driver");
  18
  19 #define MAX_SHM_INSTANCES       1
  20
  21 enum {
  22         MBX_ACC0,
  23         MBX_ACC1,
  24         MBX_DSP
  25 };
  26
  27 static struct shmdev_layer shmdev_lyr[MAX_SHM_INSTANCES];
  28
  29 static unsigned int shm_start;
  30 static unsigned int shm_size;
  31
  32 module_param(shm_size, uint  , 0440);
  33 MODULE_PARM_DESC(shm_total_size, "Start of SHM shared memory");
  34
  35 module_param(shm_start, uint  , 0440);
  36 MODULE_PARM_DESC(shm_total_start, "Total Size of SHM shared memory");
  37
  38 static int shmdev_send_msg(u32 dev_id, u32 mbx_msg)
  39 {
  40         /* Always block until msg is written successfully */
  41         mbox_send(shmdev_lyr[dev_id].hmbx, mbx_msg, true);
  42         return 0;
  43 }
  44
  45 static int shmdev_mbx_setup(void *pshmdrv_cb, struct shmdev_layer *pshm_dev,
  46                                                          void *pshm_drv)
  47 {
  48         /*
  49          * For UX5500, we have only 1 SHM instance which uses MBX0
  50          * for communication with the peer modem
  51          */
  52         pshm_dev->hmbx = mbox_setup(MBX_ACC0, pshmdrv_cb, pshm_drv);
  53
  54         if (!pshm_dev->hmbx)
  55                 return -ENODEV;
  56         else
  57                 return 0;
  58 }
  59
  60 static int __init caif_shmdev_init(void)
  61 {
  62         int i, result;
  63
  64         /* Loop is currently overkill, there is only one instance */
  65         for (i = 0; i < MAX_SHM_INSTANCES; i++) {
  66
  67                 shmdev_lyr[i].shm_base_addr = shm_start;
  68                 shmdev_lyr[i].shm_total_sz = shm_size;
  69
  70                 if (((char *)shmdev_lyr[i].shm_base_addr == NULL)
  71                                || (shmdev_lyr[i].shm_total_sz <= 0))    {
  72                         pr_warn("ERROR,"
  73                                 "Shared memory Address and/or Size incorrect"
  74                                 ", Bailing out ...\n");
  75                         result = -EINVAL;
  76                         goto clean;
  77                 }
  78
  79                 pr_info("SHM AREA (instance %d) STARTS"
  80                         " AT %p\n", i, (char *)shmdev_lyr[i].shm_base_addr);
  81
  82                 shmdev_lyr[i].shm_id = i;
  83                 shmdev_lyr[i].pshmdev_mbxsend = shmdev_send_msg;
  84                 shmdev_lyr[i].pshmdev_mbxsetup = shmdev_mbx_setup;
  85
  86                 /*
  87                  * Finally, CAIF core module is called with details in place:
  88                  * 1. SHM base address
  89                  * 2. SHM size
  90                  * 3. MBX handle
  91                  */
  92                 result = caif_shmcore_probe(&shmdev_lyr[i]);
  93                 if (result) {
  94                         pr_warn("ERROR[%d],"
  95                                 "Could not probe SHM core (instance %d)"
  96                                 " Bailing out ...\n", result, i);
  97                         goto clean;
  98                 }
  99         }
 100
 101         return 0;
 102
 103 clean:
 104         /*
 105          * For now, we assume that even if one instance of SHM fails, we bail
 106          * out of the driver support completely. For this, we need to release
 107          * any memory allocated and unregister any instance of SHM net device.
 108          */
 109         for (i = 0; i < MAX_SHM_INSTANCES; i++) {
 110                 if (shmdev_lyr[i].pshm_netdev)
 111                         unregister_netdev(shmdev_lyr[i].pshm_netdev);
 112         }
 113         return result;
 114 }
 115
 116 static void __exit caif_shmdev_exit(void)
 117 {
 118         int i;
 119
 120         for (i = 0; i < MAX_SHM_INSTANCES; i++) {
 121                 caif_shmcore_remove(shmdev_lyr[i].pshm_netdev);
 122                 kfree((void *)shmdev_lyr[i].shm_base_addr);
 123         }
 124
 125 }
 126
 127 module_init(caif_shmdev_init);
 128 module_exit(caif_shmdev_exit);