diff options
Diffstat (limited to 'drivers/dahdi/xpp/parport_debug.c')
-rw-r--r-- | drivers/dahdi/xpp/parport_debug.c | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/drivers/dahdi/xpp/parport_debug.c b/drivers/dahdi/xpp/parport_debug.c new file mode 100644 index 0000000..93049ef --- /dev/null +++ b/drivers/dahdi/xpp/parport_debug.c @@ -0,0 +1,113 @@ +/* + * Written by Oron Peled <oron@actcom.co.il> + * Copyright (C) 2007, Xorcom + * + * All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ +#include <linux/version.h> + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +# warning "This module is tested only with 2.6 kernels" +#endif + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/parport.h> +#include "parport_debug.h" + +static struct parport *debug_sync_parport = NULL; +static int parport_toggles[8]; /* 8 bit flip-flop */ + +void flip_parport_bit(unsigned char bitnum) +{ + static unsigned char last_value; + spinlock_t lock = SPIN_LOCK_UNLOCKED; + unsigned long flags; + unsigned char mask; + unsigned char value; + + if(!debug_sync_parport) { + if(printk_ratelimit()) { + printk(KERN_NOTICE "%s: no debug parallel port\n", + THIS_MODULE->name); + } + return; + } + BUG_ON(bitnum > 7); + mask = 1 << bitnum; + spin_lock_irqsave(&lock, flags); + value = last_value & ~mask; + if(parport_toggles[bitnum] % 2) /* square wave */ + value |= mask; + last_value = value; + parport_toggles[bitnum]++; + spin_unlock_irqrestore(&lock, flags); + parport_write_data(debug_sync_parport, value); +} +EXPORT_SYMBOL(flip_parport_bit); + +static void parport_attach(struct parport *port) +{ + printk(KERN_INFO "%s: Using %s for debugging\n", THIS_MODULE->name, port->name); + if(debug_sync_parport) { + printk(KERN_ERR "%s: Using %s, ignore new attachment %s\n", + THIS_MODULE->name, debug_sync_parport->name, port->name); + return; + } + parport_get_port(port); + debug_sync_parport = port; +} + +static void parport_detach(struct parport *port) +{ + printk(KERN_INFO "%s: Releasing %s\n", THIS_MODULE->name, port->name); + if(debug_sync_parport != port) { + printk(KERN_ERR "%s: Using %s, ignore new detachment %s\n", + THIS_MODULE->name, debug_sync_parport->name, port->name); + return; + } + parport_put_port(debug_sync_parport); + debug_sync_parport = NULL; +} + +static struct parport_driver debug_parport_driver = { + .name = "parport_debug", + .attach = parport_attach, + .detach = parport_detach, +}; + +int __init parallel_dbg_init(void) +{ + int ret; + + ret = parport_register_driver(&debug_parport_driver); + return ret; +} + +void __exit parallel_dbg_cleanup(void) +{ + parport_unregister_driver(&debug_parport_driver); +} + +MODULE_DESCRIPTION("Use parallel port to debug drivers"); +MODULE_AUTHOR("Oron Peled <oron@actcom.co.il>"); +MODULE_LICENSE("GPL"); +MODULE_VERSION("$Id:"); + +module_init(parallel_dbg_init); +module_exit(parallel_dbg_cleanup); |