arch/blackfin/mach-bf561/coreb.c

   1 /* Load firmware into Core B on a BF561
   2  *
   3  * Copyright 2004-2009 Analog Devices Inc.
   4  * Licensed under the GPL-2 or later.
   5  */
   6
   7 /* The Core B reset func requires code in the application that is loaded into
   8  * Core B.  In order to reset, the application needs to install an interrupt
   9  * handler for Supplemental Interrupt 0, that sets RETI to 0xff600000 and
  10  * writes bit 11 of SICB_SYSCR when bit 5 of SICA_SYSCR is 0.  This causes Core
  11  * B to stall when Supplemental Interrupt 0 is set, and will reset PC to
  12  * 0xff600000 when COREB_SRAM_INIT is cleared.
  13  */
  14
  15 #include <linux/device.h>
  16 #include <linux/fs.h>
  17 #include <linux/kernel.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/module.h>
  20
  21 #define CMD_COREB_START         _IO('b', 0)
  22 #define CMD_COREB_STOP          _IO('b', 1)
  23 #define CMD_COREB_RESET         _IO('b', 2)
  24
  25 static long
  26 coreb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  27 {
  28         int ret = 0;
  29
  30         switch (cmd) {
  31         case CMD_COREB_START:
  32                 bfin_write_SYSCR(bfin_read_SYSCR() & ~0x0020);
  33                 break;
  34         case CMD_COREB_STOP:
  35                 bfin_write_SYSCR(bfin_read_SYSCR() | 0x0020);
  36                 bfin_write_SICB_SYSCR(bfin_read_SICB_SYSCR() | 0x0080);
  37                 break;
  38         case CMD_COREB_RESET:
  39                 bfin_write_SICB_SYSCR(bfin_read_SICB_SYSCR() | 0x0080);
  40                 break;
  41         default:
  42                 ret = -EINVAL;
  43                 break;
  44         }
  45
  46         CSYNC();
  47
  48         return ret;
  49 }
  50
  51 static const struct file_operations coreb_fops = {
  52         .owner          = THIS_MODULE,
  53         .unlocked_ioctl = coreb_ioctl,
  54         .llseek         = noop_llseek,
  55 };
  56
  57 static struct miscdevice coreb_dev = {
  58         .minor = MISC_DYNAMIC_MINOR,
  59         .name  = "coreb",
  60         .fops  = &coreb_fops,
  61 };
  62
  63 static int __init bf561_coreb_init(void)
  64 {
  65         return misc_register(&coreb_dev);
  66 }
  67 module_init(bf561_coreb_init);
  68
  69 static void __exit bf561_coreb_exit(void)
  70 {
  71         misc_deregister(&coreb_dev);
  72 }
  73 module_exit(bf561_coreb_exit);
  74
  75 MODULE_AUTHOR("Bas Vermeulen <bvermeul@blackstar.xs4all.nl>");
  76 MODULE_DESCRIPTION("BF561 Core B Support");
  77 MODULE_LICENSE("GPL");