bay.c

/*
 *  bay.c - ACPI removable drive bay driver
 *
 *  Copyright (C) 2006 Kristen Carlson Accardi <kristen.c.accardi@intel.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/notifier.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>

#define ACPI_BAY_DRIVER_NAME "ACPI Removable Drive Bay Driver"

ACPI_MODULE_NAME("bay")
MODULE_AUTHOR("Kristen Carlson Accardi");
MODULE_DESCRIPTION(ACPI_BAY_DRIVER_NAME);
MODULE_LICENSE("GPL");
#define ACPI_BAY_CLASS "bay"
#define ACPI_BAY_COMPONENT	0x10000000
#define _COMPONENT ACPI_BAY_COMPONENT
#define bay_dprintk(h,s) {\
	char prefix[80] = {'\0'};\
	struct acpi_buffer buffer = {sizeof(prefix), prefix};\
	acpi_get_name(h, ACPI_FULL_PATHNAME, &buffer);\
	printk(KERN_DEBUG PREFIX "%s: %s\n", prefix, s); }

static void bay_notify(acpi_handle handle, u32 event, void *data);
static int acpi_bay_add(struct acpi_device *device);
static int acpi_bay_remove(struct acpi_device *device, int type);
static int acpi_bay_match(struct acpi_device *device,
				struct acpi_driver *driver);

static struct acpi_driver acpi_bay_driver = {
	.name = ACPI_BAY_DRIVER_NAME,
	.class = ACPI_BAY_CLASS,
	.ops = {
		.add = acpi_bay_add,
		.remove = acpi_bay_remove,
		.match = acpi_bay_match,
		},
};

struct bay {
	acpi_handle handle;
	char *name;
	struct list_head list;
	struct proc_dir_entry *proc;
};

LIST_HEAD(drive_bays);

static struct proc_dir_entry *acpi_bay_dir;

/*****************************************************************************
 *                         Drive Bay functions                               *
 *****************************************************************************/
/**
 * is_ejectable - see if a device is ejectable
 * @handle: acpi handle of the device
 *
 * If an acpi object has a _EJ0 method, then it is ejectable
 */
static int is_ejectable(acpi_handle handle)
{
	acpi_status status;
	acpi_handle tmp;

	status = acpi_get_handle(handle, "_EJ0", &tmp);
	if (ACPI_FAILURE(status))
		return 0;
	return 1;
}

/**
 * bay_present - see if the bay device is present
 * @bay: the drive bay
 *
 * execute the _STA method.
 */
static int bay_present(struct bay *bay)
{
	unsigned long sta;
	acpi_status status;

	if (bay) {
		status = acpi_evaluate_integer(bay->handle, "_STA", NULL, &sta);
		if (ACPI_SUCCESS(status) && sta)
			return 1;
	}
	return 0;
}

/**
 * eject_device - respond to an eject request
 * @handle - the device to eject
 *
 * Call this devices _EJ0 method.
 */
static void eject_device(acpi_handle handle)
{
	struct acpi_object_list arg_list;
	union acpi_object arg;

	bay_dprintk(handle, "Ejecting device");

	arg_list.count = 1;
	arg_list.pointer = &arg;
	arg.type = ACPI_TYPE_INTEGER;
	arg.integer.value = 1;

	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_EJ0",
					      &arg_list, NULL)))
		pr_debug("Failed to evaluate _EJ0!\n");
}


/**
 * is_ata - see if a device is an ata device
 * @handle: acpi handle of the device
 *
 * If an acpi object has one of 4 ATA ACPI methods defined,
 * then it is an ATA device
 */
static int is_ata(acpi_handle handle)
{
	acpi_handle tmp;

	if ((ACPI_SUCCESS(acpi_get_handle(handle, "_GTF", &tmp))) ||
	   (ACPI_SUCCESS(acpi_get_handle(handle, "_GTM", &tmp))) ||
	   (ACPI_SUCCESS(acpi_get_handle(handle, "_STM", &tmp))) ||
	   (ACPI_SUCCESS(acpi_get_handle(handle, "_SDD", &tmp))))
		return 1;

	return 0;
}

/**
 * parent_is_ata(acpi_handle handle)
 *
 */
static int parent_is_ata(acpi_handle handle)
{
	acpi_handle phandle;

	if (acpi_get_parent(handle, &phandle))
		return 0;

	return is_ata(phandle);
}

/**
 * is_ejectable_bay - see if a device is an ejectable drive bay
 * @handle: acpi handle of the device
 *
 * If an acpi object is ejectable and has one of the ACPI ATA
 * methods defined, then we can safely call it an ejectable
 * drive bay
 */
static int is_ejectable_bay(acpi_handle handle)
{
	if ((is_ata(handle) || parent_is_ata(handle)) && is_ejectable(handle))
		return 1;
	return 0;
}

/**
 * eject_removable_drive - try to eject this drive
 * @dev : the device structure of the drive
 *
 * If a device is a removable drive that requires an _EJ0 method
 * to be executed in order to safely remove from the system, do
 * it.  ATM - always returns success
 */
int eject_removable_drive(struct device *dev)
{
	acpi_handle handle = DEVICE_ACPI_HANDLE(dev);

	if (handle) {
		bay_dprintk(handle, "Got device handle");
		if (is_ejectable_bay(handle))
			eject_device(handle);
	} else {
		printk("No acpi handle for device\n");
	}

	/* should I return an error code? */
	return 0;
}
EXPORT_SYMBOL_GPL(eject_removable_drive);

static int acpi_bay_add(struct acpi_device *device)
{
	bay_dprintk(device->handle, "adding bay device");
	strcpy(acpi_device_name(device), "Dockable Bay");
	strcpy(acpi_device_class(device), "bay");
	return 0;
}

static int acpi_bay_status_seq_show(struct seq_file *seq, void *offset)
{
	struct bay *bay = (struct bay *)seq->private;

	if (!bay)
		return 0;

	if (bay_present(bay))
		seq_printf(seq, "present\n");
	else
		seq_printf(seq, "removed\n");

	return 0;
}

static ssize_t
acpi_bay_write_eject(struct file *file,
		      const char __user * buffer,
		      size_t count, loff_t * data)
{
	struct seq_file *m = (struct seq_file *)file->private_data;
	struct bay *bay = (struct bay *)m->private;
	char str[12] = { 0 };
	u32 state = 0;

	/* FIXME - our only valid value here is 1 */
	if (!bay || count + 1 > sizeof str)
		return -EINVAL;

	if (copy_from_user(str, buffer, count))
		return -EFAULT;

	str[count] = 0;
	state = simple_strtoul(str, NULL, 0);
	if (state)
		eject_device(bay->handle);

	return count;
}

static int
acpi_bay_status_open_fs(struct inode *inode, struct file *file)
{
	return single_open(file, acpi_bay_status_seq_show,
			   PDE(inode)->data);
}

static int
acpi_bay_eject_open_fs(struct inode *inode, struct file *file)
{
	return single_open(file, acpi_bay_status_seq_show,
			   PDE(inode)->data);
}

static struct file_operations acpi_bay_status_fops = {
	.open = acpi_bay_status_open_fs,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static struct file_operations acpi_bay_eject_fops = {
	.open = acpi_bay_eject_open_fs,
	.read = seq_read,
	.write = acpi_bay_write_eject,
	.llseek = seq_lseek,
	.release = single_release,
};
#if 0
static struct file_operations acpi_bay_insert_fops = {
	.open = acpi_bay_insert_open_fs,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};
#endif
static int acpi_bay_add_fs(struct bay *bay)
{
	struct proc_dir_entry *entry = NULL;

	if (!bay)
		return -EINVAL;

	/*
	 * create a proc entry for this device
	 * we need to do this a little bit differently than normal
	 * acpi device drivers because our device may not be present
	 * at the moment, and therefore we have no acpi_device struct
	 */

	bay->proc = proc_mkdir(bay->name, acpi_bay_dir);

	/* 'status' [R] */
	entry = create_proc_entry("status",
				  S_IRUGO, bay->proc);
	if (!entry)
		return -EIO;
	else {
		entry->proc_fops = &acpi_bay_status_fops;
		entry->data = bay;
		entry->owner = THIS_MODULE;
	}
	/* 'eject' [W] */
	entry = create_proc_entry("eject",
				  S_IWUGO, bay->proc);
	if (!entry)
		return -EIO;
	else {
		entry->proc_fops = &acpi_bay_eject_fops;
		entry->data = bay;
		entry->owner = THIS_MODULE;
	}
#if 0
	/* 'insert' [W] */
	entry = create_proc_entry("insert",
				  S_IWUGO, bay->proc);
	if (!entry)
		return -EIO;
	else {
		entry->proc_fops = &acpi_bay_insert_fops;
		entry->data = bay;
		entry->owner = THIS_MODULE;
	}
#endif
	return 0;
}

static void acpi_bay_remove_fs(struct bay *bay)
{
	if (!bay)
		return;

	if (bay->proc) {
		remove_proc_entry("status", bay->proc);
		remove_proc_entry("eject", bay->proc);
#if 0
		remove_proc_entry("insert", bay->proc);
#endif
		remove_proc_entry(bay->name, acpi_bay_dir);
		bay->proc = NULL;
	}
}

static int bay_is_dock_device(acpi_handle handle)
{
	acpi_handle parent;

	acpi_get_parent(handle, &parent);

	/* if the device or it's parent is dependent on the
	 * dock, then we are a dock device
	 */
	return (is_dock_device(handle) || is_dock_device(parent));
}

static int bay_add(acpi_handle handle)
{
	acpi_status status;
	struct bay *new_bay;
	struct acpi_buffer nbuffer = {ACPI_ALLOCATE_BUFFER, NULL};
	acpi_get_name(handle, ACPI_FULL_PATHNAME, &nbuffer);

	bay_dprintk(handle, "Adding notify handler");

	/*
	 * if this is the first bay device found, make the root
	 * proc entry
	 */
	if (acpi_bay_dir == NULL)
		acpi_bay_dir = proc_mkdir(ACPI_BAY_CLASS, acpi_root_dir);

	/*
	 * Initialize bay device structure
	 */
	new_bay = kmalloc(GFP_ATOMIC, sizeof(*new_bay));
	INIT_LIST_HEAD(&new_bay->list);
	new_bay->handle = handle;
	new_bay->name = (char *)nbuffer.pointer;
	list_add(&new_bay->list, &drive_bays);
	acpi_bay_add_fs(new_bay);

	/* register for events on this device */
	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
			bay_notify, new_bay);
	if (ACPI_FAILURE(status)) {
		printk(KERN_ERR PREFIX "Error installing bay notify handler\n");
	}

	/* if we are on a dock station, we should register for dock
	 * notifications.
	 */
	if (bay_is_dock_device(handle)) {
		bay_dprintk(handle, "Is dependent on dock\n");
		register_hotplug_dock_device(handle, bay_notify, new_bay);
	}
	printk(KERN_INFO PREFIX "Bay [%s] Added\n", new_bay->name);
	return 0;
}

static int acpi_bay_remove(struct acpi_device *device, int type)
{
	/*** FIXME: do something here */
	return 0;
}

static int acpi_bay_match(struct acpi_device *device,
				struct acpi_driver *driver)
{
	if (!device || !driver)
		return -EINVAL;

	if (is_ejectable_bay(device->handle)) {
		bay_dprintk(device->handle, "matching bay device");
		return 0;
	}

	return -ENODEV;
}

/**
 * bay_create_acpi_device - add new devices to acpi
 * @handle - handle of the device to add
 *
 *  This function will create a new acpi_device for the given
 *  handle if one does not exist already.  This should cause
 *  acpi to scan for drivers for the given devices, and call
 *  matching driver's add routine.
 *
 *  Returns a pointer to the acpi_device corresponding to the handle.
 */
static struct acpi_device * bay_create_acpi_device(acpi_handle handle)
{
	struct acpi_device *device = NULL;
	struct acpi_device *parent_device;
	acpi_handle parent;
	int ret;

	bay_dprintk(handle, "Trying to get device");
	if (acpi_bus_get_device(handle, &device)) {
		/*
		 * no device created for this object,
		 * so we should create one.
		 */
		bay_dprintk(handle, "No device for handle");
		acpi_get_parent(handle, &parent);
		if (acpi_bus_get_device(parent, &parent_device))
			parent_device = NULL;

		ret = acpi_bus_add(&device, parent_device, handle,
			ACPI_BUS_TYPE_DEVICE);
		if (ret) {
			pr_debug("error adding bus, %x\n",
				-ret);
			return NULL;
		}
	}
	return device;
}

/**
 * bay_notify - act upon an acpi bay notification
 * @handle: the bay handle
 * @event: the acpi event
 * @data: our driver data struct
 *
 */
static void bay_notify(acpi_handle handle, u32 event, void *data)
{
	struct acpi_device *dev;
	struct bay *bay = data;

	bay_dprintk(handle, "Bay event");

	switch(event) {
	case ACPI_NOTIFY_BUS_CHECK:
		printk("Bus Check\n");
	case ACPI_NOTIFY_DEVICE_CHECK:
		printk("Device Check\n");
		dev = bay_create_acpi_device(handle);
		if (dev)
			acpi_bus_generate_event(dev, event, 0);
		else
			printk("No device for generating event\n");
		/* wouldn't it be a good idea to just rescan SATA
		 * right here?
		 */
		break;
	case ACPI_NOTIFY_EJECT_REQUEST:
		printk("Eject request\n");
		dev = bay_create_acpi_device(handle);
		if (dev)
			acpi_bus_generate_event(dev, event, 0);
		else
			printk("No device for generating eventn");

		/* wouldn't it be a good idea to just call the
		 * eject_device here if we were a SATA device?
		 */
		break;
	default:
		printk("unknown event %d\n", event);
	}
}

static acpi_status
find_bay(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	int *count = (int *)context;

	/*
	 * there could be more than one ejectable bay.
	 * so, just return AE_OK always so that every object
	 * will be checked.
	 */
	if (is_ejectable_bay(handle)) {
		bay_dprintk(handle, "found ejectable bay");
		bay_add(handle);
		(*count)++;
	}
	return AE_OK;
}

static int __init bay_init(void)
{
	int bays = 0;

	acpi_bay_dir = NULL;
	INIT_LIST_HEAD(&drive_bays);

	/* look for dockable drive bays */
	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
		ACPI_UINT32_MAX, find_bay, &bays, NULL);

	if (bays) {
		if ((acpi_bus_register_driver(&acpi_bay_driver) < 0)) {
			printk(KERN_ERR "Unable to register bay driver\n");
			if (acpi_bay_dir)
				remove_proc_entry(ACPI_BAY_CLASS,
					acpi_root_dir);
		}
	}

	if (!bays)
		return -ENODEV;

	return 0;
}

static void __exit bay_exit(void)
{
	struct bay *bay, *tmp;

	list_for_each_entry_safe(bay, tmp, &drive_bays, list) {
		if (is_dock_device(bay->handle))
			unregister_hotplug_dock_device(bay->handle);
		acpi_bay_remove_fs(bay);
		acpi_remove_notify_handler(bay->handle, ACPI_SYSTEM_NOTIFY,
			bay_notify);
		kfree(bay->name);
		kfree(bay);
	}

	if (acpi_bay_dir)
		remove_proc_entry(ACPI_BAY_CLASS, acpi_root_dir);

	acpi_bus_unregister_driver(&acpi_bay_driver);
}

postcore_initcall(bay_init);
module_exit(bay_exit);