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