[PATCH] Driver for IBM service processor - updated (1/2)

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.

Here is the non-filesystem part:

1 files changed, 175 insertions, 0 deletions

diff --git a/drivers/misc/ibmasm/command.c b/drivers/misc/ibmasm/command.c
new file mode 100644
index 000000000000..245b0058381d
--- /dev/null
+++ b/drivers/misc/ibmasm/command.c
@@ -0,0 +1,175 @@
+
+/*
+ * 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> 
+ *
+ */
+
+#include "ibmasm.h"
+
+static void exec_next_command(struct service_processor *sp);
+static void free_command(struct kobject *kobj);
+
+static struct kobj_type ibmasm_cmd_kobj_type = {
+	.release = free_command,
+};
+
+
+struct command *ibmasm_new_command(size_t buffer_size)
+{
+	struct command *cmd;
+
+	if (buffer_size > IBMASM_CMD_MAX_BUFFER_SIZE)
+		return NULL;
+
+	cmd = kmalloc(sizeof(struct command), GFP_KERNEL);
+	if (cmd == NULL)
+		return NULL;
+
+	memset(cmd, 0, sizeof(*cmd));
+
+	cmd->buffer = kmalloc(buffer_size, GFP_KERNEL);
+	if (cmd->buffer == NULL) {
+		kfree(cmd);
+		return NULL;
+	}
+	memset(cmd->buffer, 0, buffer_size);
+	cmd->buffer_size = buffer_size;
+
+	kobject_init(&cmd->kobj);
+	cmd->kobj.ktype = &ibmasm_cmd_kobj_type;
+
+	cmd->status = IBMASM_CMD_PENDING;
+	init_waitqueue_head(&cmd->wait);
+	INIT_LIST_HEAD(&cmd->queue_node);
+
+	return cmd;
+}
+
+static void free_command(struct kobject *kobj)
+{
+	struct command *cmd = to_command(kobj);
+ 
+	list_del(&cmd->queue_node);
+	kfree(cmd->buffer);
+	kfree(cmd);
+}
+
+static void enqueue_command(struct service_processor *sp, struct command *cmd)
+{
+	list_add_tail(&cmd->queue_node, &sp->command_queue);
+}
+
+static struct command *dequeue_command(struct service_processor *sp)
+{
+	struct command *cmd;
+	struct list_head *next;
+
+	if (list_empty(&sp->command_queue))
+		return NULL;
+
+	next = sp->command_queue.next;
+	list_del_init(next);
+	cmd = list_entry(next, struct command, queue_node);
+
+	return cmd;
+}
+
+static inline void do_exec_command(struct service_processor *sp)
+{
+	if (ibmasm_send_i2o_message(sp)) {
+		sp->current_command->status = IBMASM_CMD_FAILED;
+		exec_next_command(sp);
+	}
+}
+	
+/**
+ * exec_command
+ * send a command to a service processor
+ * Commands are executed sequentially. One command (sp->current_command)
+ * is sent to the service processor. Once the interrupt handler gets a
+ * message of type command_response, the message is copied into
+ * the current commands buffer, 
+ */
+void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sp->lock, flags);
+
+	if (!sp->current_command) {
+		command_get(cmd);
+		sp->current_command = cmd;
+		spin_unlock_irqrestore(&sp->lock, flags);
+
+		do_exec_command(sp);
+	} else {
+		enqueue_command(sp, cmd);
+		spin_unlock_irqrestore(&sp->lock, flags);
+	}
+}
+
+static void exec_next_command(struct service_processor *sp)
+{
+	unsigned long flags;
+
+	wake_up(&sp->current_command->wait);
+	command_put(sp->current_command);
+
+	spin_lock_irqsave(&sp->lock, flags);
+	sp->current_command = dequeue_command(sp);
+	if (sp->current_command) {
+		command_get(sp->current_command);
+		spin_unlock_irqrestore(&sp->lock, flags);
+		do_exec_command(sp);
+	} else {
+		spin_unlock_irqrestore(&sp->lock, flags);
+	}
+}
+
+/** 
+ * Sleep until a command has failed or a response has been received
+ * and the command status been updated by the interrupt handler.
+ * (see receive_response).
+ */
+void ibmasm_wait_for_response(struct command *cmd, int timeout)
+{
+	wait_event_interruptible_timeout(cmd->wait,
+				cmd->status == IBMASM_CMD_COMPLETE ||
+				cmd->status == IBMASM_CMD_FAILED,
+				timeout * HZ);
+}
+
+/**
+ * receive_command_response
+ * called by the interrupt handler when a dot command of type command_response
+ * was received.
+ */
+void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
+{
+	struct command *cmd = sp->current_command;
+
+	if (!sp->current_command) 
+		return; 
+
+	memcpy(cmd->buffer, response, min(size, cmd->buffer_size));
+	cmd->status = IBMASM_CMD_COMPLETE;
+	exec_next_command(sp);
+}