[PATCH] Driver for IBM RSA service processor (2/2)

[Max Asbock]

Here is a device driver for the IBM xSeries RSA service processor.
The ibmasm driver is mainly intended to be used in conjunction with a user space 
API and systems management applications that need to get in-band access to
the service processor, such as sending commands or waiting for events.
For the remote video feature the driver relays remote mouse and keyboard 
events to user space. 
By itself the driver also allows the OS to make use the UART on the service
processor board as a regular serial line.

The user interface to the driver is a custom file system. It does not use sysfs since
the operations on the files are somewhat beyond the one file / one value rule for sysfs.
Since it is not strictly a char driver I put it into the drivers/misc directory.

The patch is fairly big, therefore I split it up into the file system part and the
everything-else part.

Any feedback is greatly appreciated.

Regards,

Max

Here is the filesytem part:

diff -urN linux-2.6.1/drivers/misc/ibmasm/ibmasmfs.c linux-2.6.1-ibmasm/drivers/misc/ibmasm/ibmasmfs.c
--- linux-2.6.1/drivers/misc/ibmasm/ibmasmfs.c	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.1-ibmasm/drivers/misc/ibmasm/ibmasmfs.c	2004-01-23 15:39:00.000000000 -0800
@@ -0,0 +1,734 @@
+/*
+ * 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@xxxxxxxxxx> 
+ *
+ */
+
+/*
+ * 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
+ * dymamically when mounted from user space:
+ *
+ *    /ibmasm
+ *    |-- 0
+ *    |   |-- command
+ *    |   |-- event
+ *    |   |-- reverse_heartbeat
+ *    |   `-- remote_video
+ *    |       |-- connected
+ *    |       |-- depth
+ *    |       |-- events
+ *    |       |-- height
+ *    |       `-- width
+ *    .
+ *    .
+ *    .
+ *    `-- n
+ *        |-- command
+ *        |-- event
+ *        |-- reverse_heartbeat
+ *        `-- remote_video
+ *            |-- connected
+ *            |-- depth
+ *            |-- events
+ *            |-- 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
+ *
+ * reverse_heartbeat: send a heartbeat to the service processor
+ * 	read: sleep (interruptible) until the reverse heartbeat fails
+ *
+ * remote_video/width
+ * remote_video/height
+ * remote_video/width: control remote display settings
+ * 	write: set value
+ * 	read: read value
+ *
+ * remote_video/connected
+ * 	read: return "1" if web browser VNC java applet is connected, 
+ * 		"0" otherwise
+ *
+ * remote_video/events
+ * 	read: sleep until a remote mouse or keyboard event occurs, then return
+ * 		then event.
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.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 super_block *ibmasmfs_get_super(struct file_system_type *fst,
+			int flags, const char *name, void *data)
+{
+	return get_sb_single(fst, flags, data, ibmasmfs_fill_super);
+}
+
+static struct super_operations ibmasmfs_s_ops = {
+	.statfs		= simple_statfs,
+	.drop_inode	= generic_delete_inode,
+};
+
+static struct file_operations *ibmasmfs_dir_ops = &simple_dir_operations;
+
+static struct file_system_type ibmasmfs_type = {
+	.owner          = THIS_MODULE,
+	.name           = "ibmasmfs",
+	.get_sb         = ibmasmfs_get_super,
+	.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;
+
+	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_mode = mode;
+		ret->i_uid = ret->i_gid = 0;
+		ret->i_blksize = PAGE_CACHE_SIZE;
+		ret->i_blocks = 0;
+		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,
+			struct file_operations *fops,
+			void *data,
+			int mode)
+{
+	struct dentry *dentry;
+	struct inode *inode;
+	struct qstr qname;
+
+	qname.name = name;
+	qname.len = strlen (name);
+	qname.hash = full_name_hash(name, qname.len);
+
+	dentry = d_alloc(parent, &qname);
+	if (!dentry)
+		return NULL;
+
+	inode = ibmasmfs_make_inode(sb, S_IFREG | mode);
+	if (!inode) {
+		dput(dentry);
+		return NULL;
+	}
+
+	inode->i_fop = fops;
+	inode->u.generic_ip = 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;
+	struct qstr qname;
+
+	qname.name = name;
+	qname.len = strlen (name);
+	qname.hash = full_name_hash(name, qname.len);
+	dentry = d_alloc(parent, &qname);
+	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()
+{
+	return register_filesystem(&ibmasmfs_type);
+}
+
+void ibmasmfs_unregister()
+{
+	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;
+	spinlock_t			lock;
+};
+
+static int command_file_open(struct inode *inode, struct file *file)
+{
+	struct ibmasmfs_command_data *command_data;
+
+	if ( !inode->u.generic_ip )
+		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->u.generic_ip;
+	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 *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 *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(count);
+	if (!cmd)
+		return -ENOMEM;
+
+	if ( copy_from_user((void *)cmd->buffer, (void *)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 command_file_ioctl(struct inode *inode, struct file *file, unsigned int ioctl_cmd, unsigned long arg)
+{
+	struct ibmasmfs_command_data *command_data = file->private_data;
+	struct command *cmd;
+	unsigned long flags;
+
+	if (ioctl_cmd != IBMASM_IO_CANCEL)
+		return -ENOTTY;
+
+	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;
+	}
+	wake_up_interruptible(&cmd->wait);
+	spin_lock_irqsave(&command_data->sp->lock, flags);
+	return 0;
+}
+
+
+static int event_file_open(struct inode *inode, struct file *file)
+{
+	struct ibmasmfs_event_data *event_data;
+	struct service_processor *sp; 
+
+	if ( !inode->u.generic_ip )
+		return -ENODEV;
+
+	sp = inode->u.generic_ip;
+
+	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;
+	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 *buf, size_t count, loff_t *offset)
+{
+	struct ibmasmfs_event_data *event_data = file->private_data;
+	struct event_reader *reader = &event_data->reader;
+	int ret;
+
+	if (*offset < 0)
+		return -EINVAL;
+	if (count == 0 || count > IBMASM_EVENT_MAX_SIZE)
+		return 0;
+	if (*offset != 0)
+		return 0;
+
+	ret = ibmasm_get_next_event(event_data->sp, reader);
+	if (ret <= 0)
+		return ret;
+
+	if (count < reader->data_size)
+		return -EINVAL;
+
+        if (copy_to_user(buf, reader->data, reader->data_size))
+		return -EFAULT;
+
+	return reader->data_size;
+}
+
+static int event_file_ioctl(struct inode *inode, struct file *file, unsigned int ioctl_cmd, unsigned long arg)
+{
+	struct ibmasmfs_event_data *event_data = file->private_data;
+
+	if (ioctl_cmd != IBMASM_IO_CANCEL)
+		return -ENOTTY;
+
+	wake_up_interruptible(&event_data->reader.wait);
+	return 0;
+}
+
+static int r_heartbeat_file_open(struct inode *inode, struct file *file)
+{
+	struct ibmasmfs_heartbeat_data *rhbeat;
+
+	if ( !inode->u.generic_ip )
+		return -ENODEV;
+
+	rhbeat = kmalloc(sizeof(struct ibmasmfs_heartbeat_data), GFP_KERNEL);
+	if (!rhbeat)
+		return -ENOMEM;
+
+	rhbeat->sp = (struct service_processor *)inode->u.generic_ip;
+	rhbeat->lock = SPIN_LOCK_UNLOCKED;
+	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 *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->lock, flags);
+	if (rhbeat->active) {
+		spin_unlock_irqrestore(&rhbeat->lock, flags);
+		return -EBUSY;
+	}
+	rhbeat->active = 1;
+	spin_unlock_irqrestore(&rhbeat->lock, flags);
+
+	result = ibmasm_start_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
+
+	spin_lock_irqsave(&rhbeat->lock, flags);
+	rhbeat->active = 0;
+	ibmasm_init_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
+	spin_unlock_irqrestore(&rhbeat->lock, flags);
+
+	return result;
+}
+
+static int r_heartbeat_file_ioctl(struct inode *inode, struct file *file, unsigned int ioctl_cmd, unsigned long arg)
+{
+	struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
+	unsigned long flags;
+
+	if (ioctl_cmd != IBMASM_IO_CANCEL)
+		return -ENOTTY;
+
+	spin_lock_irqsave(&rhbeat->lock, flags);
+	if (!rhbeat->active) {
+		spin_unlock_irqrestore(&rhbeat->lock, flags);
+		return 0;
+	}
+	spin_unlock_irqrestore(&rhbeat->lock, flags);
+
+	ibmasm_stop_reverse_heartbeat(&rhbeat->heartbeat);
+	return 0;
+}
+
+static int remote_settings_file_open(struct inode *inode, struct file *file)
+{
+	file->private_data = inode->u.generic_ip;
+	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 *buf, size_t count, loff_t *offset)
+{
+	unsigned long address = (unsigned long)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 *ubuff, size_t count, loff_t *offset)
+{
+	unsigned long address = (unsigned long)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 = kmalloc (count + 1, GFP_KERNEL);
+	if (!buff)
+		return -ENOMEM;
+
+	memset(buff, 0x0, count + 1);
+
+	if ( copy_from_user((void *)buff, (void *)ubuff, count) ) {
+		kfree(buff);
+		return -EFAULT;
+	}
+	
+	value = simple_strtoul(buff, NULL, 10);
+	writel(value, address);
+	kfree(buff);
+
+	return count;
+}
+
+static int remote_event_file_open(struct inode *inode, struct file *file)
+{
+	struct service_processor *sp;
+	unsigned long flags;
+	struct remote_queue *q;
+	
+	file->private_data = inode->u.generic_ip;
+	sp = file->private_data;
+	q = &sp->remote_queue;
+
+	/* allow only one event reader */
+	spin_lock_irqsave(&sp->lock, flags);
+	if (q->open) {
+		spin_unlock_irqrestore(&sp->lock, flags);
+		return -EBUSY;
+	}
+	q->open = 1;
+	spin_unlock_irqrestore(&sp->lock, flags);
+
+	enable_mouse_interrupts(sp);
+	
+	return 0;
+}
+
+static int remote_event_file_close(struct inode *inode, struct file *file)
+{
+	struct service_processor *sp = file->private_data;
+
+	disable_mouse_interrupts(sp);
+	wake_up_interruptible(&sp->remote_queue.wait);
+	sp->remote_queue.open = 0;
+
+	return 0;
+}
+
+static ssize_t remote_event_file_read(struct file *file, char *buf, size_t count, loff_t *offset)
+{
+	struct service_processor *sp = file->private_data;
+	struct remote_queue *q = &sp->remote_queue;
+	size_t data_size;
+	struct remote_event *reader = q->reader;
+	size_t num_events;
+
+	if (wait_event_interruptible(q->wait, q->reader != q->writer))
+		return -ERESTARTSYS;
+
+	/* only get multiples of struct remote_event */
+	num_events = min((count/sizeof(struct remote_event)), ibmasm_events_available(q));
+	if (!num_events)
+		return 0;
+
+	data_size = num_events * sizeof(struct remote_event);
+
+	if (copy_to_user(buf, reader, data_size))
+		return -EFAULT;
+
+	ibmasm_advance_reader(q, num_events);
+
+	return data_size;
+}
+
+
+static struct file_operations command_fops = {
+	.open =		command_file_open,
+	.release =	command_file_close,
+	.read =		command_file_read,
+	.write =	command_file_write,
+	.ioctl = 	command_file_ioctl,
+};
+
+static struct file_operations event_fops = {
+	.open =		event_file_open,
+	.release =	event_file_close,
+	.read =		event_file_read,
+	.ioctl 		event_file_ioctl,
+};
+
+static struct file_operations r_heartbeat_fops = {
+	.open =		r_heartbeat_file_open,
+	.release =	r_heartbeat_file_close,
+	.read =		r_heartbeat_file_read,
+	.ioctl =	r_heartbeat_file_ioctl,
+};
+
+static 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,
+};
+
+static struct file_operations remote_event_fops = {
+	.open =		remote_event_file_open,
+	.release =	remote_event_file_close,
+	.read =		remote_event_file_read,
+};
+
+
+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, 0600);
+		ibmasmfs_create_file(sb, dir, "event", &event_fops, sp, 0400);
+		ibmasmfs_create_file(sb, dir, "reverse_heartbeat", &r_heartbeat_fops, sp, 0400);
+
+		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), 0600);
+		ibmasmfs_create_file(sb, remote_dir, "height", &remote_settings_fops, (void *)display_height(sp), 0600);
+		ibmasmfs_create_file(sb, remote_dir, "depth", &remote_settings_fops, (void *)display_depth(sp), 0600);
+		ibmasmfs_create_file(sb, remote_dir, "connected", &remote_settings_fops, (void *)vnc_status(sp), 0400);
+		ibmasmfs_create_file(sb, remote_dir, "events", &remote_event_fops, (void *)sp, 0400);
+	}
+}

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