v4.19.13 snapshot.
diff --git a/drivers/acpi/acpi_dbg.c b/drivers/acpi/acpi_dbg.c
new file mode 100644
index 0000000..f21c99e
--- /dev/null
+++ b/drivers/acpi/acpi_dbg.c
@@ -0,0 +1,804 @@
+/*
+ * ACPI AML interfacing support
+ *
+ * Copyright (C) 2015, Intel Corporation
+ * Authors: Lv Zheng <lv.zheng@intel.com>
+ *
+ * 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.
+ */
+
+/* #define DEBUG */
+#define pr_fmt(fmt) "ACPI: AML: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/kthread.h>
+#include <linux/proc_fs.h>
+#include <linux/debugfs.h>
+#include <linux/circ_buf.h>
+#include <linux/acpi.h>
+#include "internal.h"
+
+#define ACPI_AML_BUF_ALIGN (sizeof (acpi_size))
+#define ACPI_AML_BUF_SIZE PAGE_SIZE
+
+#define circ_count(circ) \
+ (CIRC_CNT((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE))
+#define circ_count_to_end(circ) \
+ (CIRC_CNT_TO_END((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE))
+#define circ_space(circ) \
+ (CIRC_SPACE((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE))
+#define circ_space_to_end(circ) \
+ (CIRC_SPACE_TO_END((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE))
+
+#define ACPI_AML_OPENED 0x0001
+#define ACPI_AML_CLOSED 0x0002
+#define ACPI_AML_IN_USER 0x0004 /* user space is writing cmd */
+#define ACPI_AML_IN_KERN 0x0008 /* kernel space is reading cmd */
+#define ACPI_AML_OUT_USER 0x0010 /* user space is reading log */
+#define ACPI_AML_OUT_KERN 0x0020 /* kernel space is writing log */
+#define ACPI_AML_USER (ACPI_AML_IN_USER | ACPI_AML_OUT_USER)
+#define ACPI_AML_KERN (ACPI_AML_IN_KERN | ACPI_AML_OUT_KERN)
+#define ACPI_AML_BUSY (ACPI_AML_USER | ACPI_AML_KERN)
+#define ACPI_AML_OPEN (ACPI_AML_OPENED | ACPI_AML_CLOSED)
+
+struct acpi_aml_io {
+ wait_queue_head_t wait;
+ unsigned long flags;
+ unsigned long users;
+ struct mutex lock;
+ struct task_struct *thread;
+ char out_buf[ACPI_AML_BUF_SIZE] __aligned(ACPI_AML_BUF_ALIGN);
+ struct circ_buf out_crc;
+ char in_buf[ACPI_AML_BUF_SIZE] __aligned(ACPI_AML_BUF_ALIGN);
+ struct circ_buf in_crc;
+ acpi_osd_exec_callback function;
+ void *context;
+ unsigned long usages;
+};
+
+static struct acpi_aml_io acpi_aml_io;
+static bool acpi_aml_initialized;
+static struct file *acpi_aml_active_reader;
+static struct dentry *acpi_aml_dentry;
+
+static inline bool __acpi_aml_running(void)
+{
+ return acpi_aml_io.thread ? true : false;
+}
+
+static inline bool __acpi_aml_access_ok(unsigned long flag)
+{
+ /*
+ * The debugger interface is in opened state (OPENED && !CLOSED),
+ * then it is allowed to access the debugger buffers from either
+ * user space or the kernel space.
+ * In addition, for the kernel space, only the debugger thread
+ * (thread ID matched) is allowed to access.
+ */
+ if (!(acpi_aml_io.flags & ACPI_AML_OPENED) ||
+ (acpi_aml_io.flags & ACPI_AML_CLOSED) ||
+ !__acpi_aml_running())
+ return false;
+ if ((flag & ACPI_AML_KERN) &&
+ current != acpi_aml_io.thread)
+ return false;
+ return true;
+}
+
+static inline bool __acpi_aml_readable(struct circ_buf *circ, unsigned long flag)
+{
+ /*
+ * Another read is not in progress and there is data in buffer
+ * available for read.
+ */
+ if (!(acpi_aml_io.flags & flag) && circ_count(circ))
+ return true;
+ return false;
+}
+
+static inline bool __acpi_aml_writable(struct circ_buf *circ, unsigned long flag)
+{
+ /*
+ * Another write is not in progress and there is buffer space
+ * available for write.
+ */
+ if (!(acpi_aml_io.flags & flag) && circ_space(circ))
+ return true;
+ return false;
+}
+
+static inline bool __acpi_aml_busy(void)
+{
+ if (acpi_aml_io.flags & ACPI_AML_BUSY)
+ return true;
+ return false;
+}
+
+static inline bool __acpi_aml_opened(void)
+{
+ if (acpi_aml_io.flags & ACPI_AML_OPEN)
+ return true;
+ return false;
+}
+
+static inline bool __acpi_aml_used(void)
+{
+ return acpi_aml_io.usages ? true : false;
+}
+
+static inline bool acpi_aml_running(void)
+{
+ bool ret;
+
+ mutex_lock(&acpi_aml_io.lock);
+ ret = __acpi_aml_running();
+ mutex_unlock(&acpi_aml_io.lock);
+ return ret;
+}
+
+static bool acpi_aml_busy(void)
+{
+ bool ret;
+
+ mutex_lock(&acpi_aml_io.lock);
+ ret = __acpi_aml_busy();
+ mutex_unlock(&acpi_aml_io.lock);
+ return ret;
+}
+
+static bool acpi_aml_used(void)
+{
+ bool ret;
+
+ /*
+ * The usage count is prepared to avoid race conditions between the
+ * starts and the stops of the debugger thread.
+ */
+ mutex_lock(&acpi_aml_io.lock);
+ ret = __acpi_aml_used();
+ mutex_unlock(&acpi_aml_io.lock);
+ return ret;
+}
+
+static bool acpi_aml_kern_readable(void)
+{
+ bool ret;
+
+ mutex_lock(&acpi_aml_io.lock);
+ ret = !__acpi_aml_access_ok(ACPI_AML_IN_KERN) ||
+ __acpi_aml_readable(&acpi_aml_io.in_crc, ACPI_AML_IN_KERN);
+ mutex_unlock(&acpi_aml_io.lock);
+ return ret;
+}
+
+static bool acpi_aml_kern_writable(void)
+{
+ bool ret;
+
+ mutex_lock(&acpi_aml_io.lock);
+ ret = !__acpi_aml_access_ok(ACPI_AML_OUT_KERN) ||
+ __acpi_aml_writable(&acpi_aml_io.out_crc, ACPI_AML_OUT_KERN);
+ mutex_unlock(&acpi_aml_io.lock);
+ return ret;
+}
+
+static bool acpi_aml_user_readable(void)
+{
+ bool ret;
+
+ mutex_lock(&acpi_aml_io.lock);
+ ret = !__acpi_aml_access_ok(ACPI_AML_OUT_USER) ||
+ __acpi_aml_readable(&acpi_aml_io.out_crc, ACPI_AML_OUT_USER);
+ mutex_unlock(&acpi_aml_io.lock);
+ return ret;
+}
+
+static bool acpi_aml_user_writable(void)
+{
+ bool ret;
+
+ mutex_lock(&acpi_aml_io.lock);
+ ret = !__acpi_aml_access_ok(ACPI_AML_IN_USER) ||
+ __acpi_aml_writable(&acpi_aml_io.in_crc, ACPI_AML_IN_USER);
+ mutex_unlock(&acpi_aml_io.lock);
+ return ret;
+}
+
+static int acpi_aml_lock_write(struct circ_buf *circ, unsigned long flag)
+{
+ int ret = 0;
+
+ mutex_lock(&acpi_aml_io.lock);
+ if (!__acpi_aml_access_ok(flag)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ if (!__acpi_aml_writable(circ, flag)) {
+ ret = -EAGAIN;
+ goto out;
+ }
+ acpi_aml_io.flags |= flag;
+out:
+ mutex_unlock(&acpi_aml_io.lock);
+ return ret;
+}
+
+static int acpi_aml_lock_read(struct circ_buf *circ, unsigned long flag)
+{
+ int ret = 0;
+
+ mutex_lock(&acpi_aml_io.lock);
+ if (!__acpi_aml_access_ok(flag)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ if (!__acpi_aml_readable(circ, flag)) {
+ ret = -EAGAIN;
+ goto out;
+ }
+ acpi_aml_io.flags |= flag;
+out:
+ mutex_unlock(&acpi_aml_io.lock);
+ return ret;
+}
+
+static void acpi_aml_unlock_fifo(unsigned long flag, bool wakeup)
+{
+ mutex_lock(&acpi_aml_io.lock);
+ acpi_aml_io.flags &= ~flag;
+ if (wakeup)
+ wake_up_interruptible(&acpi_aml_io.wait);
+ mutex_unlock(&acpi_aml_io.lock);
+}
+
+static int acpi_aml_write_kern(const char *buf, int len)
+{
+ int ret;
+ struct circ_buf *crc = &acpi_aml_io.out_crc;
+ int n;
+ char *p;
+
+ ret = acpi_aml_lock_write(crc, ACPI_AML_OUT_KERN);
+ if (ret < 0)
+ return ret;
+ /* sync tail before inserting logs */
+ smp_mb();
+ p = &crc->buf[crc->head];
+ n = min(len, circ_space_to_end(crc));
+ memcpy(p, buf, n);
+ /* sync head after inserting logs */
+ smp_wmb();
+ crc->head = (crc->head + n) & (ACPI_AML_BUF_SIZE - 1);
+ acpi_aml_unlock_fifo(ACPI_AML_OUT_KERN, true);
+ return n;
+}
+
+static int acpi_aml_readb_kern(void)
+{
+ int ret;
+ struct circ_buf *crc = &acpi_aml_io.in_crc;
+ char *p;
+
+ ret = acpi_aml_lock_read(crc, ACPI_AML_IN_KERN);
+ if (ret < 0)
+ return ret;
+ /* sync head before removing cmds */
+ smp_rmb();
+ p = &crc->buf[crc->tail];
+ ret = (int)*p;
+ /* sync tail before inserting cmds */
+ smp_mb();
+ crc->tail = (crc->tail + 1) & (ACPI_AML_BUF_SIZE - 1);
+ acpi_aml_unlock_fifo(ACPI_AML_IN_KERN, true);
+ return ret;
+}
+
+/*
+ * acpi_aml_write_log() - Capture debugger output
+ * @msg: the debugger output
+ *
+ * This function should be used to implement acpi_os_printf() to filter out
+ * the debugger output and store the output into the debugger interface
+ * buffer. Return the size of stored logs or errno.
+ */
+static ssize_t acpi_aml_write_log(const char *msg)
+{
+ int ret = 0;
+ int count = 0, size = 0;
+
+ if (!acpi_aml_initialized)
+ return -ENODEV;
+ if (msg)
+ count = strlen(msg);
+ while (count > 0) {
+again:
+ ret = acpi_aml_write_kern(msg + size, count);
+ if (ret == -EAGAIN) {
+ ret = wait_event_interruptible(acpi_aml_io.wait,
+ acpi_aml_kern_writable());
+ /*
+ * We need to retry when the condition
+ * becomes true.
+ */
+ if (ret == 0)
+ goto again;
+ break;
+ }
+ if (ret < 0)
+ break;
+ size += ret;
+ count -= ret;
+ }
+ return size > 0 ? size : ret;
+}
+
+/*
+ * acpi_aml_read_cmd() - Capture debugger input
+ * @msg: the debugger input
+ * @size: the size of the debugger input
+ *
+ * This function should be used to implement acpi_os_get_line() to capture
+ * the debugger input commands and store the input commands into the
+ * debugger interface buffer. Return the size of stored commands or errno.
+ */
+static ssize_t acpi_aml_read_cmd(char *msg, size_t count)
+{
+ int ret = 0;
+ int size = 0;
+
+ /*
+ * This is ensured by the running fact of the debugger thread
+ * unless a bug is introduced.
+ */
+ BUG_ON(!acpi_aml_initialized);
+ while (count > 0) {
+again:
+ /*
+ * Check each input byte to find the end of the command.
+ */
+ ret = acpi_aml_readb_kern();
+ if (ret == -EAGAIN) {
+ ret = wait_event_interruptible(acpi_aml_io.wait,
+ acpi_aml_kern_readable());
+ /*
+ * We need to retry when the condition becomes
+ * true.
+ */
+ if (ret == 0)
+ goto again;
+ }
+ if (ret < 0)
+ break;
+ *(msg + size) = (char)ret;
+ size++;
+ count--;
+ if (ret == '\n') {
+ /*
+ * acpi_os_get_line() requires a zero terminated command
+ * string.
+ */
+ *(msg + size - 1) = '\0';
+ break;
+ }
+ }
+ return size > 0 ? size : ret;
+}
+
+static int acpi_aml_thread(void *unsed)
+{
+ acpi_osd_exec_callback function = NULL;
+ void *context;
+
+ mutex_lock(&acpi_aml_io.lock);
+ if (acpi_aml_io.function) {
+ acpi_aml_io.usages++;
+ function = acpi_aml_io.function;
+ context = acpi_aml_io.context;
+ }
+ mutex_unlock(&acpi_aml_io.lock);
+
+ if (function)
+ function(context);
+
+ mutex_lock(&acpi_aml_io.lock);
+ acpi_aml_io.usages--;
+ if (!__acpi_aml_used()) {
+ acpi_aml_io.thread = NULL;
+ wake_up(&acpi_aml_io.wait);
+ }
+ mutex_unlock(&acpi_aml_io.lock);
+
+ return 0;
+}
+
+/*
+ * acpi_aml_create_thread() - Create AML debugger thread
+ * @function: the debugger thread callback
+ * @context: the context to be passed to the debugger thread
+ *
+ * This function should be used to implement acpi_os_execute() which is
+ * used by the ACPICA debugger to create the debugger thread.
+ */
+static int acpi_aml_create_thread(acpi_osd_exec_callback function, void *context)
+{
+ struct task_struct *t;
+
+ mutex_lock(&acpi_aml_io.lock);
+ acpi_aml_io.function = function;
+ acpi_aml_io.context = context;
+ mutex_unlock(&acpi_aml_io.lock);
+
+ t = kthread_create(acpi_aml_thread, NULL, "aml");
+ if (IS_ERR(t)) {
+ pr_err("Failed to create AML debugger thread.\n");
+ return PTR_ERR(t);
+ }
+
+ mutex_lock(&acpi_aml_io.lock);
+ acpi_aml_io.thread = t;
+ acpi_set_debugger_thread_id((acpi_thread_id)(unsigned long)t);
+ wake_up_process(t);
+ mutex_unlock(&acpi_aml_io.lock);
+ return 0;
+}
+
+static int acpi_aml_wait_command_ready(bool single_step,
+ char *buffer, size_t length)
+{
+ acpi_status status;
+
+ if (single_step)
+ acpi_os_printf("\n%1c ", ACPI_DEBUGGER_EXECUTE_PROMPT);
+ else
+ acpi_os_printf("\n%1c ", ACPI_DEBUGGER_COMMAND_PROMPT);
+
+ status = acpi_os_get_line(buffer, length, NULL);
+ if (ACPI_FAILURE(status))
+ return -EINVAL;
+ return 0;
+}
+
+static int acpi_aml_notify_command_complete(void)
+{
+ return 0;
+}
+
+static int acpi_aml_open(struct inode *inode, struct file *file)
+{
+ int ret = 0;
+ acpi_status status;
+
+ mutex_lock(&acpi_aml_io.lock);
+ /*
+ * The debugger interface is being closed, no new user is allowed
+ * during this period.
+ */
+ if (acpi_aml_io.flags & ACPI_AML_CLOSED) {
+ ret = -EBUSY;
+ goto err_lock;
+ }
+ if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
+ /*
+ * Only one reader is allowed to initiate the debugger
+ * thread.
+ */
+ if (acpi_aml_active_reader) {
+ ret = -EBUSY;
+ goto err_lock;
+ } else {
+ pr_debug("Opening debugger reader.\n");
+ acpi_aml_active_reader = file;
+ }
+ } else {
+ /*
+ * No writer is allowed unless the debugger thread is
+ * ready.
+ */
+ if (!(acpi_aml_io.flags & ACPI_AML_OPENED)) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ }
+ if (acpi_aml_active_reader == file) {
+ pr_debug("Opening debugger interface.\n");
+ mutex_unlock(&acpi_aml_io.lock);
+
+ pr_debug("Initializing debugger thread.\n");
+ status = acpi_initialize_debugger();
+ if (ACPI_FAILURE(status)) {
+ pr_err("Failed to initialize debugger.\n");
+ ret = -EINVAL;
+ goto err_exit;
+ }
+ pr_debug("Debugger thread initialized.\n");
+
+ mutex_lock(&acpi_aml_io.lock);
+ acpi_aml_io.flags |= ACPI_AML_OPENED;
+ acpi_aml_io.out_crc.head = acpi_aml_io.out_crc.tail = 0;
+ acpi_aml_io.in_crc.head = acpi_aml_io.in_crc.tail = 0;
+ pr_debug("Debugger interface opened.\n");
+ }
+ acpi_aml_io.users++;
+err_lock:
+ if (ret < 0) {
+ if (acpi_aml_active_reader == file)
+ acpi_aml_active_reader = NULL;
+ }
+ mutex_unlock(&acpi_aml_io.lock);
+err_exit:
+ return ret;
+}
+
+static int acpi_aml_release(struct inode *inode, struct file *file)
+{
+ mutex_lock(&acpi_aml_io.lock);
+ acpi_aml_io.users--;
+ if (file == acpi_aml_active_reader) {
+ pr_debug("Closing debugger reader.\n");
+ acpi_aml_active_reader = NULL;
+
+ pr_debug("Closing debugger interface.\n");
+ acpi_aml_io.flags |= ACPI_AML_CLOSED;
+
+ /*
+ * Wake up all user space/kernel space blocked
+ * readers/writers.
+ */
+ wake_up_interruptible(&acpi_aml_io.wait);
+ mutex_unlock(&acpi_aml_io.lock);
+ /*
+ * Wait all user space/kernel space readers/writers to
+ * stop so that ACPICA command loop of the debugger thread
+ * should fail all its command line reads after this point.
+ */
+ wait_event(acpi_aml_io.wait, !acpi_aml_busy());
+
+ /*
+ * Then we try to terminate the debugger thread if it is
+ * not terminated.
+ */
+ pr_debug("Terminating debugger thread.\n");
+ acpi_terminate_debugger();
+ wait_event(acpi_aml_io.wait, !acpi_aml_used());
+ pr_debug("Debugger thread terminated.\n");
+
+ mutex_lock(&acpi_aml_io.lock);
+ acpi_aml_io.flags &= ~ACPI_AML_OPENED;
+ }
+ if (acpi_aml_io.users == 0) {
+ pr_debug("Debugger interface closed.\n");
+ acpi_aml_io.flags &= ~ACPI_AML_CLOSED;
+ }
+ mutex_unlock(&acpi_aml_io.lock);
+ return 0;
+}
+
+static int acpi_aml_read_user(char __user *buf, int len)
+{
+ int ret;
+ struct circ_buf *crc = &acpi_aml_io.out_crc;
+ int n;
+ char *p;
+
+ ret = acpi_aml_lock_read(crc, ACPI_AML_OUT_USER);
+ if (ret < 0)
+ return ret;
+ /* sync head before removing logs */
+ smp_rmb();
+ p = &crc->buf[crc->tail];
+ n = min(len, circ_count_to_end(crc));
+ if (copy_to_user(buf, p, n)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ /* sync tail after removing logs */
+ smp_mb();
+ crc->tail = (crc->tail + n) & (ACPI_AML_BUF_SIZE - 1);
+ ret = n;
+out:
+ acpi_aml_unlock_fifo(ACPI_AML_OUT_USER, ret >= 0);
+ return ret;
+}
+
+static ssize_t acpi_aml_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ int ret = 0;
+ int size = 0;
+
+ if (!count)
+ return 0;
+ if (!access_ok(VERIFY_WRITE, buf, count))
+ return -EFAULT;
+
+ while (count > 0) {
+again:
+ ret = acpi_aml_read_user(buf + size, count);
+ if (ret == -EAGAIN) {
+ if (file->f_flags & O_NONBLOCK)
+ break;
+ else {
+ ret = wait_event_interruptible(acpi_aml_io.wait,
+ acpi_aml_user_readable());
+ /*
+ * We need to retry when the condition
+ * becomes true.
+ */
+ if (ret == 0)
+ goto again;
+ }
+ }
+ if (ret < 0) {
+ if (!acpi_aml_running())
+ ret = 0;
+ break;
+ }
+ if (ret) {
+ size += ret;
+ count -= ret;
+ *ppos += ret;
+ break;
+ }
+ }
+ return size > 0 ? size : ret;
+}
+
+static int acpi_aml_write_user(const char __user *buf, int len)
+{
+ int ret;
+ struct circ_buf *crc = &acpi_aml_io.in_crc;
+ int n;
+ char *p;
+
+ ret = acpi_aml_lock_write(crc, ACPI_AML_IN_USER);
+ if (ret < 0)
+ return ret;
+ /* sync tail before inserting cmds */
+ smp_mb();
+ p = &crc->buf[crc->head];
+ n = min(len, circ_space_to_end(crc));
+ if (copy_from_user(p, buf, n)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ /* sync head after inserting cmds */
+ smp_wmb();
+ crc->head = (crc->head + n) & (ACPI_AML_BUF_SIZE - 1);
+ ret = n;
+out:
+ acpi_aml_unlock_fifo(ACPI_AML_IN_USER, ret >= 0);
+ return n;
+}
+
+static ssize_t acpi_aml_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ int ret = 0;
+ int size = 0;
+
+ if (!count)
+ return 0;
+ if (!access_ok(VERIFY_READ, buf, count))
+ return -EFAULT;
+
+ while (count > 0) {
+again:
+ ret = acpi_aml_write_user(buf + size, count);
+ if (ret == -EAGAIN) {
+ if (file->f_flags & O_NONBLOCK)
+ break;
+ else {
+ ret = wait_event_interruptible(acpi_aml_io.wait,
+ acpi_aml_user_writable());
+ /*
+ * We need to retry when the condition
+ * becomes true.
+ */
+ if (ret == 0)
+ goto again;
+ }
+ }
+ if (ret < 0) {
+ if (!acpi_aml_running())
+ ret = 0;
+ break;
+ }
+ if (ret) {
+ size += ret;
+ count -= ret;
+ *ppos += ret;
+ }
+ }
+ return size > 0 ? size : ret;
+}
+
+static __poll_t acpi_aml_poll(struct file *file, poll_table *wait)
+{
+ __poll_t masks = 0;
+
+ poll_wait(file, &acpi_aml_io.wait, wait);
+ if (acpi_aml_user_readable())
+ masks |= EPOLLIN | EPOLLRDNORM;
+ if (acpi_aml_user_writable())
+ masks |= EPOLLOUT | EPOLLWRNORM;
+
+ return masks;
+}
+
+static const struct file_operations acpi_aml_operations = {
+ .read = acpi_aml_read,
+ .write = acpi_aml_write,
+ .poll = acpi_aml_poll,
+ .open = acpi_aml_open,
+ .release = acpi_aml_release,
+ .llseek = generic_file_llseek,
+};
+
+static const struct acpi_debugger_ops acpi_aml_debugger = {
+ .create_thread = acpi_aml_create_thread,
+ .read_cmd = acpi_aml_read_cmd,
+ .write_log = acpi_aml_write_log,
+ .wait_command_ready = acpi_aml_wait_command_ready,
+ .notify_command_complete = acpi_aml_notify_command_complete,
+};
+
+int __init acpi_aml_init(void)
+{
+ int ret = 0;
+
+ if (!acpi_debugfs_dir) {
+ ret = -ENOENT;
+ goto err_exit;
+ }
+
+ /* Initialize AML IO interface */
+ mutex_init(&acpi_aml_io.lock);
+ init_waitqueue_head(&acpi_aml_io.wait);
+ acpi_aml_io.out_crc.buf = acpi_aml_io.out_buf;
+ acpi_aml_io.in_crc.buf = acpi_aml_io.in_buf;
+ acpi_aml_dentry = debugfs_create_file("acpidbg",
+ S_IFREG | S_IRUGO | S_IWUSR,
+ acpi_debugfs_dir, NULL,
+ &acpi_aml_operations);
+ if (acpi_aml_dentry == NULL) {
+ ret = -ENODEV;
+ goto err_exit;
+ }
+ ret = acpi_register_debugger(THIS_MODULE, &acpi_aml_debugger);
+ if (ret)
+ goto err_fs;
+ acpi_aml_initialized = true;
+
+err_fs:
+ if (ret) {
+ debugfs_remove(acpi_aml_dentry);
+ acpi_aml_dentry = NULL;
+ }
+err_exit:
+ return ret;
+}
+
+void __exit acpi_aml_exit(void)
+{
+ if (acpi_aml_initialized) {
+ acpi_unregister_debugger(&acpi_aml_debugger);
+ if (acpi_aml_dentry) {
+ debugfs_remove(acpi_aml_dentry);
+ acpi_aml_dentry = NULL;
+ }
+ acpi_aml_initialized = false;
+ }
+}
+
+module_init(acpi_aml_init);
+module_exit(acpi_aml_exit);
+
+MODULE_AUTHOR("Lv Zheng");
+MODULE_DESCRIPTION("ACPI debugger userspace IO driver");
+MODULE_LICENSE("GPL");