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/*
* Copyright (C) 2007 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <asm/ocd.h>
static long ocd_count;
static spinlock_t ocd_lock;
/**
* ocd_enable - enable on-chip debugging
* @child: task to be debugged
*
* If @child is non-NULL, ocd_enable() first checks if debugging has
* already been enabled for @child, and if it has, does nothing.
*
* If @child is NULL (e.g. when debugging the kernel), or debugging
* has not already been enabled for it, ocd_enable() increments the
* reference count and enables the debugging hardware.
*/
void ocd_enable(struct task_struct *child)
{
u32 dc;
if (child)
pr_debug("ocd_enable: child=%s [%u]\n",
child->comm, child->pid);
else
pr_debug("ocd_enable (no child)\n");
if (!child || !test_and_set_tsk_thread_flag(child, TIF_DEBUG)) {
spin_lock(&ocd_lock);
ocd_count++;
dc = ocd_read(DC);
dc |= (1 << OCD_DC_MM_BIT) | (1 << OCD_DC_DBE_BIT);
ocd_write(DC, dc);
spin_unlock(&ocd_lock);
}
}
/**
* ocd_disable - disable on-chip debugging
* @child: task that was being debugged, but isn't anymore
*
* If @child is non-NULL, ocd_disable() checks if debugging is enabled
* for @child, and if it isn't, does nothing.
*
* If @child is NULL (e.g. when debugging the kernel), or debugging is
* enabled, ocd_disable() decrements the reference count, and if it
* reaches zero, disables the debugging hardware.
*/
void ocd_disable(struct task_struct *child)
{
u32 dc;
if (!child)
pr_debug("ocd_disable (no child)\n");
else if (test_tsk_thread_flag(child, TIF_DEBUG))
pr_debug("ocd_disable: child=%s [%u]\n",
child->comm, child->pid);
if (!child || test_and_clear_tsk_thread_flag(child, TIF_DEBUG)) {
spin_lock(&ocd_lock);
ocd_count--;
WARN_ON(ocd_count < 0);
if (ocd_count <= 0) {
dc = ocd_read(DC);
dc &= ~((1 << OCD_DC_MM_BIT) | (1 << OCD_DC_DBE_BIT));
ocd_write(DC, dc);
}
spin_unlock(&ocd_lock);
}
}
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
#include <linux/module.h>
static struct dentry *ocd_debugfs_root;
static struct dentry *ocd_debugfs_DC;
static struct dentry *ocd_debugfs_DS;
static struct dentry *ocd_debugfs_count;
static int ocd_DC_get(void *data, u64 *val)
{
*val = ocd_read(DC);
return 0;
}
static int ocd_DC_set(void *data, u64 val)
{
ocd_write(DC, val);
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_DC, ocd_DC_get, ocd_DC_set, "0x%08llx\n");
static int ocd_DS_get(void *data, u64 *val)
{
*val = ocd_read(DS);
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_DS, ocd_DS_get, NULL, "0x%08llx\n");
static int ocd_count_get(void *data, u64 *val)
{
*val = ocd_count;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_count, ocd_count_get, NULL, "%lld\n");
static void ocd_debugfs_init(void)
{
struct dentry *root;
root = debugfs_create_dir("ocd", NULL);
if (IS_ERR(root) || !root)
goto err_root;
ocd_debugfs_root = root;
ocd_debugfs_DC = debugfs_create_file("DC", S_IRUSR | S_IWUSR,
root, NULL, &fops_DC);
if (!ocd_debugfs_DC)
goto err_DC;
ocd_debugfs_DS = debugfs_create_file("DS", S_IRUSR, root,
NULL, &fops_DS);
if (!ocd_debugfs_DS)
goto err_DS;
ocd_debugfs_count = debugfs_create_file("count", S_IRUSR, root,
NULL, &fops_count);
if (!ocd_debugfs_count)
goto err_count;
return;
err_count:
debugfs_remove(ocd_debugfs_DS);
err_DS:
debugfs_remove(ocd_debugfs_DC);
err_DC:
debugfs_remove(ocd_debugfs_root);
err_root:
printk(KERN_WARNING "OCD: Failed to create debugfs entries\n");
}
#else
static inline void ocd_debugfs_init(void)
{
}
#endif
static int __init ocd_init(void)
{
spin_lock_init(&ocd_lock);
ocd_debugfs_init();
return 0;
}
arch_initcall(ocd_init);
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