text: /*
   * IBM ASM Service Processor Device Driver
   *
   * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   *
   * Copyright (C) IBM Corporation, 2004
   *
   * Author: Max Asböck <amax@us.ibm.com>
   *
   */
  
  /*
   * Parts of this code are based on an article by Jonathan Corbet
   * that appeared in Linux Weekly News.
   */
  
  
  /*
   * The IBMASM file virtual filesystem. It creates the following hierarchy
   * dynamically when mounted from user space:
   *
   *    /ibmasm
   *    |-- 0
   *    |   |-- command
   *    |   |-- event
   *    |   |-- reverse_heartbeat
   *    |   `-- remote_video
   *    |       |-- depth
   *    |       |-- height
   *    |       `-- width
   *    .
   *    .
   *    .
   *    `-- n
   *        |-- command
   *        |-- event
   *        |-- reverse_heartbeat
   *        `-- remote_video
   *            |-- depth
   *            |-- height
   *            `-- width
   *
   * For each service processor the following files are created:
   *
   * command: execute dot commands
   *	write: execute a dot command on the service processor
   *	read: return the result of a previously executed dot command
   *
   * events: listen for service processor events
   *	read: sleep (interruptible) until an event occurs
   *      write: wakeup sleeping event listener
   *
   * reverse_heartbeat: send a heartbeat to the service processor
   *	read: sleep (interruptible) until the reverse heartbeat fails
   *      write: wakeup sleeping heartbeat listener
   *
   * remote_video/width
   * remote_video/height
   * remote_video/width: control remote display settings
   *	write: set value
   *	read: read value
   */
  
  #include <linux/fs.h>
  #include <linux/pagemap.h>
  #include <linux/slab.h>
  #include <asm/uaccess.h>
  #include <asm/io.h>
  #include "ibmasm.h"
  #include "remote.h"
  #include "dot_command.h"
  
  #define IBMASMFS_MAGIC 0x66726f67
  
  static LIST_HEAD(service_processors);
  
  static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode);
  static void ibmasmfs_create_files (struct super_block *sb, struct dentry *root);
  static int ibmasmfs_fill_super (struct super_block *sb, void *data, int silent);
  
  
  static struct dentry *ibmasmfs_mount(struct file_system_type *fst,
  			int flags, const char *name, void *data)
  {
  	return mount_single(fst, flags, data, ibmasmfs_fill_super);
  }
  
  static const struct super_operations ibmasmfs_s_ops = {
  	.statfs		= simple_statfs,
  	.drop_inode	= generic_delete_inode,
  };
  
  static const struct file_operations *ibmasmfs_dir_ops = &simple_dir_operations;
  
  static struct file_system_type ibmasmfs_type = {
  	.owner          = THIS_MODULE,
  	.name           = "ibmasmfs",
  	.mount          = ibmasmfs_mount,
  	.kill_sb        = kill_litter_super,
  };
  
  static int ibmasmfs_fill_super (struct super_block *sb, void *data, int silent)
  {
  	struct inode *root;
  	struct dentry *root_dentry;
  
  	sb->s_blocksize = PAGE_CACHE_SIZE;
  	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
  	sb->s_magic = IBMASMFS_MAGIC;
  	sb->s_op = &ibmasmfs_s_ops;
  	sb->s_time_gran = 1;
  
  	root = ibmasmfs_make_inode (sb, S_IFDIR | 0500);
  	if (!root)
  		return -ENOMEM;
  
  	root->i_op = &simple_dir_inode_operations;
  	root->i_fop = ibmasmfs_dir_ops;
  
  	root_dentry = d_alloc_root(root);
  	if (!root_dentry) {
  		iput(root);
  		return -ENOMEM;
  	}
  	sb->s_root = root_dentry;
  
  	ibmasmfs_create_files(sb, root_dentry);
  	return 0;
  }
  
  static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode)
  {
  	struct inode *ret = new_inode(sb);
  
  	if (ret) {
  		ret->i_ino = get_next_ino();
  		ret->i_mode = mode;
  		ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
  	}
  	return ret;
  }
  
  static struct dentry *ibmasmfs_create_file (struct super_block *sb,
  			struct dentry *parent,
  			const char *name,
  			const struct file_operations *fops,
  			void *data,
  			int mode)
  {
  	struct dentry *dentry;
  	struct inode *inode;
  
  	dentry = d_alloc_name(parent, name);
  	if (!dentry)
  		return NULL;
  
  	inode = ibmasmfs_make_inode(sb, S_IFREG | mode);
  	if (!inode) {
  		dput(dentry);
  		return NULL;
  	}
  
  	inode->i_fop = fops;
  	inode->i_private = data;
  
  	d_add(dentry, inode);
  	return dentry;
  }
  
  static struct dentry *ibmasmfs_create_dir (struct super_block *sb,
  				struct dentry *parent,
  				const char *name)
  {
  	struct dentry *dentry;
  	struct inode *inode;
  
  	dentry = d_alloc_name(parent, name);
  	if (!dentry)
  		return NULL;
  
  	inode = ibmasmfs_make_inode(sb, S_IFDIR | 0500);
  	if (!inode) {
  		dput(dentry);
  		return NULL;
  	}
  
  	inode->i_op = &simple_dir_inode_operations;
  	inode->i_fop = ibmasmfs_dir_ops;
  
  	d_add(dentry, inode);
  	return dentry;
  }
  
  int ibmasmfs_register(void)
  {
  	return register_filesystem(&ibmasmfs_type);
  }
  
  void ibmasmfs_unregister(void)
  {
  	unregister_filesystem(&ibmasmfs_type);
  }
  
  void ibmasmfs_add_sp(struct service_processor *sp)
  {
  	list_add(&sp->node, &service_processors);
  }
  
  /* struct to save state between command file operations */
  struct ibmasmfs_command_data {
  	struct service_processor	*sp;
  	struct command			*command;
  };
  
  /* struct to save state between event file operations */
  struct ibmasmfs_event_data {
  	struct service_processor	*sp;
  	struct event_reader		reader;
  	int				active;
  };
  
  /* struct to save state between reverse heartbeat file operations */
  struct ibmasmfs_heartbeat_data {
  	struct service_processor	*sp;
  	struct reverse_heartbeat	heartbeat;
  	int				active;
  };
  
  static int command_file_open(struct inode *inode, struct file *file)
  {
  	struct ibmasmfs_command_data *command_data;
  
  	if (!inode->i_private)
  		return -ENODEV;
  
  	command_data = kmalloc(sizeof(struct ibmasmfs_command_data), GFP_KERNEL);
  	if (!command_data)
  		return -ENOMEM;
  
  	command_data->command = NULL;
  	command_data->sp = inode->i_private;
  	file->private_data = command_data;
  	return 0;
  }
  
  static int command_file_close(struct inode *inode, struct file *file)
  {
  	struct ibmasmfs_command_data *command_data = file->private_data;
  
  	if (command_data->command)
  		command_put(command_data->command);
  
  	kfree(command_data);
  	return 0;
  }
  
  static ssize_t command_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  {
  	struct ibmasmfs_command_data *command_data = file->private_data;
  	struct command *cmd;
  	int len;
  	unsigned long flags;
  
  	if (*offset < 0)
  		return -EINVAL;
  	if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
  		return 0;
  	if (*offset != 0)
  		return 0;
  
  	spin_lock_irqsave(&command_data->sp->lock, flags);
  	cmd = command_data->command;
  	if (cmd == NULL) {
  		spin_unlock_irqrestore(&command_data->sp->lock, flags);
  		return 0;
  	}
  	command_data->command = NULL;
  	spin_unlock_irqrestore(&command_data->sp->lock, flags);
  
  	if (cmd->status != IBMASM_CMD_COMPLETE) {
  		command_put(cmd);
  		return -EIO;
  	}
  	len = min(count, cmd->buffer_size);
  	if (copy_to_user(buf, cmd->buffer, len)) {
  		command_put(cmd);
  		return -EFAULT;
  	}
  	command_put(cmd);
  
  	return len;
  }
  
  static ssize_t command_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
  {
  	struct ibmasmfs_command_data *command_data = file->private_data;
  	struct command *cmd;
  	unsigned long flags;
  
  	if (*offset < 0)
  		return -EINVAL;
  	if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
  		return 0;
  	if (*offset != 0)
  		return 0;
  
  	/* commands are executed sequentially, only one command at a time */
  	if (command_data->command)
  		return -EAGAIN;
  
  	cmd = ibmasm_new_command(command_data->sp, count);
  	if (!cmd)
  		return -ENOMEM;
  
  	if (copy_from_user(cmd->buffer, ubuff, count)) {
  		command_put(cmd);
  		return -EFAULT;
  	}
  
  	spin_lock_irqsave(&command_data->sp->lock, flags);
  	if (command_data->command) {
  		spin_unlock_irqrestore(&command_data->sp->lock, flags);
  		command_put(cmd);
  		return -EAGAIN;
  	}
  	command_data->command = cmd;
  	spin_unlock_irqrestore(&command_data->sp->lock, flags);
  
  	ibmasm_exec_command(command_data->sp, cmd);
  	ibmasm_wait_for_response(cmd, get_dot_command_timeout(cmd->buffer));
  
  	return count;
  }
  
  static int event_file_open(struct inode *inode, struct file *file)
  {
  	struct ibmasmfs_event_data *event_data;
  	struct service_processor *sp;
  
  	if (!inode->i_private)
  		return -ENODEV;
  
  	sp = inode->i_private;
  
  	event_data = kmalloc(sizeof(struct ibmasmfs_event_data), GFP_KERNEL);
  	if (!event_data)
  		return -ENOMEM;
  
  	ibmasm_event_reader_register(sp, &event_data->reader);
  
  	event_data->sp = sp;
  	event_data->active = 0;
  	file->private_data = event_data;
  	return 0;
  }
  
  static int event_file_close(struct inode *inode, struct file *file)
  {
  	struct ibmasmfs_event_data *event_data = file->private_data;
  
  	ibmasm_event_reader_unregister(event_data->sp, &event_data->reader);
  	kfree(event_data);
  	return 0;
  }
  
  static ssize_t event_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  {
  	struct ibmasmfs_event_data *event_data = file->private_data;
  	struct event_reader *reader = &event_data->reader;
  	struct service_processor *sp = event_data->sp;
  	int ret;
  	unsigned long flags;
  
  	if (*offset < 0)
  		return -EINVAL;
  	if (count == 0 || count > IBMASM_EVENT_MAX_SIZE)
  		return 0;
  	if (*offset != 0)
  		return 0;
  
  	spin_lock_irqsave(&sp->lock, flags);
  	if (event_data->active) {
  		spin_unlock_irqrestore(&sp->lock, flags);
  		return -EBUSY;
  	}
  	event_data->active = 1;
  	spin_unlock_irqrestore(&sp->lock, flags);
  
  	ret = ibmasm_get_next_event(sp, reader);
  	if (ret <= 0)
  		goto out;
  
  	if (count < reader->data_size) {
  		ret = -EINVAL;
  		goto out;
  	}
  
          if (copy_to_user(buf, reader->data, reader->data_size)) {
  		ret = -EFAULT;
  		goto out;
  	}
  	ret = reader->data_size;
  
  out:
  	event_data->active = 0;
  	return ret;
  }
  
  static ssize_t event_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
  {
  	struct ibmasmfs_event_data *event_data = file->private_data;
  
  	if (*offset < 0)
  		return -EINVAL;
  	if (count != 1)
  		return 0;
  	if (*offset != 0)
  		return 0;
  
  	ibmasm_cancel_next_event(&event_data->reader);
  	return 0;
  }
  
  static int r_heartbeat_file_open(struct inode *inode, struct file *file)
  {
  	struct ibmasmfs_heartbeat_data *rhbeat;
  
  	if (!inode->i_private)
  		return -ENODEV;
  
  	rhbeat = kmalloc(sizeof(struct ibmasmfs_heartbeat_data), GFP_KERNEL);
  	if (!rhbeat)
  		return -ENOMEM;
  
  	rhbeat->sp = inode->i_private;
  	rhbeat->active = 0;
  	ibmasm_init_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
  	file->private_data = rhbeat;
  	return 0;
  }
  
  static int r_heartbeat_file_close(struct inode *inode, struct file *file)
  {
  	struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
  
  	kfree(rhbeat);
  	return 0;
  }
  
  static ssize_t r_heartbeat_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  {
  	struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
  	unsigned long flags;
  	int result;
  
  	if (*offset < 0)
  		return -EINVAL;
  	if (count == 0 || count > 1024)
  		return 0;
  	if (*offset != 0)
  		return 0;
  
  	/* allow only one reverse heartbeat per process */
  	spin_lock_irqsave(&rhbeat->sp->lock, flags);
  	if (rhbeat->active) {
  		spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
  		return -EBUSY;
  	}
  	rhbeat->active = 1;
  	spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
  
  	result = ibmasm_start_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
  	rhbeat->active = 0;
  
  	return result;
  }
  
  static ssize_t r_heartbeat_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
  {
  	struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
  
  	if (*offset < 0)
  		return -EINVAL;
  	if (count != 1)
  		return 0;
  	if (*offset != 0)
  		return 0;
  
  	if (rhbeat->active)
  		ibmasm_stop_reverse_heartbeat(&rhbeat->heartbeat);
  
  	return 1;
  }
  
  static int remote_settings_file_open(struct inode *inode, struct file *file)
  {
  	file->private_data = inode->i_private;
  	return 0;
  }
  
  static int remote_settings_file_close(struct inode *inode, struct file *file)
  {
  	return 0;
  }
  
  static ssize_t remote_settings_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
  {
  	void __iomem *address = (void __iomem *)file->private_data;
  	unsigned char *page;
  	int retval;
  	int len = 0;
  	unsigned int value;
  
  	if (*offset < 0)
  		return -EINVAL;
  	if (count == 0 || count > 1024)
  		return 0;
  	if (*offset != 0)
  		return 0;
  
  	page = (unsigned char *)__get_free_page(GFP_KERNEL);
  	if (!page)
  		return -ENOMEM;
  
  	value = readl(address);
  	len = sprintf(page, "%d\n", value);
  
  	if (copy_to_user(buf, page, len)) {
  		retval = -EFAULT;
  		goto exit;
  	}
  	*offset += len;
  	retval = len;
  
  exit:
  	free_page((unsigned long)page);
  	return retval;
  }
  
  static ssize_t remote_settings_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
  {
  	void __iomem *address = (void __iomem *)file->private_data;
  	char *buff;
  	unsigned int value;
  
  	if (*offset < 0)
  		return -EINVAL;
  	if (count == 0 || count > 1024)
  		return 0;
  	if (*offset != 0)
  		return 0;
  
  	buff = kzalloc (count + 1, GFP_KERNEL);
  	if (!buff)
  		return -ENOMEM;
  
  
  	if (copy_from_user(buff, ubuff, count)) {
  		kfree(buff);
  		return -EFAULT;
  	}
  
  	value = simple_strtoul(buff, NULL, 10);
  	writel(value, address);
  	kfree(buff);
  
  	return count;
  }
  
  static const struct file_operations command_fops = {
  	.open =		command_file_open,
  	.release =	command_file_close,
  	.read =		command_file_read,
  	.write =	command_file_write,
  	.llseek =	generic_file_llseek,
  };
  
  static const struct file_operations event_fops = {
  	.open =		event_file_open,
  	.release =	event_file_close,
  	.read =		event_file_read,
  	.write =	event_file_write,
  	.llseek =	generic_file_llseek,
  };
  
  static const struct file_operations r_heartbeat_fops = {
  	.open =		r_heartbeat_file_open,
  	.release =	r_heartbeat_file_close,
  	.read =		r_heartbeat_file_read,
  	.write =	r_heartbeat_file_write,
  	.llseek =	generic_file_llseek,
  };
  
  static const struct file_operations remote_settings_fops = {
  	.open =		remote_settings_file_open,
  	.release =	remote_settings_file_close,
  	.read =		remote_settings_file_read,
  	.write =	remote_settings_file_write,
  	.llseek =	generic_file_llseek,
  };
  
  
  static void ibmasmfs_create_files (struct super_block *sb, struct dentry *root)
  {
  	struct list_head *entry;
  	struct service_processor *sp;
  
  	list_for_each(entry, &service_processors) {
  		struct dentry *dir;
  		struct dentry *remote_dir;
  		sp = list_entry(entry, struct service_processor, node);
  		dir = ibmasmfs_create_dir(sb, root, sp->dirname);
  		if (!dir)
  			continue;
  
  		ibmasmfs_create_file(sb, dir, "command", &command_fops, sp, S_IRUSR|S_IWUSR);
  		ibmasmfs_create_file(sb, dir, "event", &event_fops, sp, S_IRUSR|S_IWUSR);
  		ibmasmfs_create_file(sb, dir, "reverse_heartbeat", &r_heartbeat_fops, sp, S_IRUSR|S_IWUSR);
  
  		remote_dir = ibmasmfs_create_dir(sb, dir, "remote_video");
  		if (!remote_dir)
  			continue;
  
  		ibmasmfs_create_file(sb, remote_dir, "width", &remote_settings_fops, (void *)display_width(sp), S_IRUSR|S_IWUSR);
  		ibmasmfs_create_file(sb, remote_dir, "height", &remote_settings_fops, (void *)display_height(sp), S_IRUSR|S_IWUSR);
  		ibmasmfs_create_file(sb, remote_dir, "depth", &remote_settings_fops, (void *)display_depth(sp), S_IRUSR|S_IWUSR);
  	}
  }
  