LXR linux/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
  25static long
  26coreb_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
  51static const struct file_operations coreb_fops = {
  52        .owner          = THIS_MODULE,
  53        .unlocked_ioctl = coreb_ioctl,
  54        .llseek         = noop_llseek,
  55};
  56
  57static struct miscdevice coreb_dev = {
  58        .minor = MISC_DYNAMIC_MINOR,
  59        .name  = "coreb",
  60        .fops  = &coreb_fops,
  61};
  62
  63static int __init bf561_coreb_init(void)
  64{
  65        return misc_register(&coreb_dev);
  66}
  67module_init(bf561_coreb_init);
  68
  69static void __exit bf561_coreb_exit(void)
  70{
  71        misc_deregister(&coreb_dev);
  72}
  73module_exit(bf561_coreb_exit);
  74
  75MODULE_AUTHOR("Bas Vermeulen <bvermeul@blackstar.xs4all.nl>");
  76MODULE_DESCRIPTION("BF561 Core B Support");
  77MODULE_LICENSE("GPL");
  78