drivers.c

该文件是rt_linux

/*
 * drivers.c
 *
 * 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.
 *
 * Copyright (c) 1999 The Puffin Group
 * Copyright (c) 2001 Matthew Wilcox for Hewlett Packard
 * Copyright (c) 2001 Helge Deller <[e-mail]>
 * 
 * The file handles registering devices and drivers, then matching them.
 * It's the closest we get to a dating agency.
 */

#include <linux/slab.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/pdc.h>
#include <asm/gsc.h>

/* See comments in include/asm-parisc/pci.h */
struct pci_dma_ops *hppa_dma_ops;

static struct parisc_driver *pa_drivers;
static struct parisc_device root;

/* This lock protects the pa_drivers list _only_ since all parisc_devices
 * are registered before smp_init() is called.  If you wish to add devices
 * after that, this muct be serialised somehow.  I recommend a semaphore
 * rather than a spinlock since driver ->probe functions are allowed to
 * sleep (for example when allocating memory).
 */
static spinlock_t pa_lock = SPIN_LOCK_UNLOCKED;

#define for_each_padev(dev) \
	for (dev = root.child; dev != NULL; dev = next_dev(dev))

#define check_dev(dev) \
	(dev->id.hw_type != HPHW_FAULTY) ? dev : next_dev(dev)

/**
 * next_dev - enumerates registered devices
 * @dev: the previous device returned from next_dev
 *
 * next_dev does a depth-first search of the tree, returning parents
 * before children.  Returns NULL when there are no more devices.
 */
struct parisc_device *next_dev(struct parisc_device *dev)
{
	if (dev->child) {
		return check_dev(dev->child);
	} else if (dev->sibling) {
		return dev->sibling;
	}

	/* Exhausted tree at this level, time to go up. */
	do {
		dev = dev->parent;
		if (dev && dev->sibling)
			return dev->sibling;
	} while (dev != &root);

	return NULL;
}

/**
 * match_device - Report whether this driver can handle this device
 * @driver: the PA-RISC driver to try
 * @dev: the PA-RISC device to try
 */
static int match_device(struct parisc_driver *driver, struct parisc_device *dev)
{
	const struct parisc_device_id *ids;

	for (ids = driver->id_table; ids->sversion; ids++) {
		if ((ids->sversion != SVERSION_ANY_ID) &&
		    (ids->sversion != dev->id.sversion))
			continue;

		if ((ids->hw_type != HWTYPE_ANY_ID) &&
		    (ids->hw_type != dev->id.hw_type))
			continue;

		if ((ids->hversion != HVERSION_ANY_ID) &&
		    (ids->hversion != dev->id.hversion))
			continue;

		return 1;
	}
	return 0;
}

static void claim_device(struct parisc_driver *driver, struct parisc_device *dev)
{
	dev->driver = driver;
	request_mem_region(dev->hpa, 0x1000, driver->name);
}

/**
 * register_parisc_driver - Register this driver if it can handle a device
 * @driver: the PA-RISC driver to try
 */
int register_parisc_driver(struct parisc_driver *driver)
{
	struct parisc_device *device;

	if (driver->next) {
		printk(KERN_WARNING 
		       "BUG: Skipping previously registered driver: %s\n",
		       driver->name);
		return 1;
	}

	for_each_padev(device) {
		if (device->driver)
			continue;
		if (!match_device(driver, device))
			continue;

		if (driver->probe(device) < 0)
			continue;
		claim_device(driver, device);
	}

	/* Note that the list is in reverse order of registration.  This
	 * may be significant if we ever actually support hotplug and have
	 * multiple drivers capable of claiming the same chip.
	 */

	spin_lock(&pa_lock);
	driver->next = pa_drivers;
	pa_drivers = driver;
	spin_unlock(&pa_lock);

	return 0;
}

/**
 * count_parisc_driver - count # of devices this driver would match
 * @driver: the PA-RISC driver to try
 *
 * Use by IOMMU support to "guess" the right size IOPdir.
 * Formula is something like memsize/(num_iommu * entry_size).
 */
int count_parisc_driver(struct parisc_driver *driver)
{
	struct parisc_device *device;
	int cnt = 0;

	for_each_padev(device) {
		if (match_device(driver, device))
			cnt++;
	}

	return cnt;
}



/**
 * unregister_parisc_driver - Unregister this driver from the list of drivers
 * @driver: the PA-RISC driver to unregister
 */
int unregister_parisc_driver(struct parisc_driver *driver)
{
	struct parisc_device *dev;

	spin_lock(&pa_lock);

	if (pa_drivers == driver) {
		/* was head of list - update head */
		pa_drivers = driver->next;
	} else {
		struct parisc_driver *prev = pa_drivers;

		while (prev && driver != prev->next) {
			prev = prev->next;
		}

		if (!prev) {
			printk(KERN_WARNING "unregister_parisc_driver: %s wasn't registered\n", driver->name);
		} else {
			/* Drop driver from list */
			prev->next = driver->next;
			driver->next = NULL;
		}

	}

	spin_unlock(&pa_lock);

	for_each_padev(dev) {
		if (dev->driver != driver)
			continue;
		dev->driver = NULL;
		release_mem_region(dev->hpa, 0x1000);
	}

	return 0;
}

static struct parisc_device *find_device_by_addr(unsigned long hpa)
{
	struct parisc_device *dev;
	for_each_padev(dev) {
		if (dev->hpa == hpa)
			return dev;
	}
	return NULL;
}

/**
 * find_pa_parent_type - Find a parent of a specific type
 * @dev: The device to start searching from
 * @type: The device type to search for.
 *
 * Walks up the device tree looking for a device of the specified type.
 * If it finds it, it returns it.  If not, it returns NULL.
 */
const struct parisc_device *find_pa_parent_type(const struct parisc_device *dev, int type)
{
	while (dev != &root) {
		if (dev->id.hw_type == type)
			return dev;
		dev = dev->parent;
	}

	return NULL;
}

static void
get_node_path(struct parisc_device *dev, struct hardware_path *path)
{
	int i = 5;
	memset(&path->bc, -1, 6);
	while (dev != &root) {
		path->bc[i--] = dev->hw_path;
		dev = dev->parent;
	}
}

static char *print_hwpath(struct hardware_path *path, char *output)
{
	int i;
	for (i = 0; i < 6; i++) {
		if (path->bc[i] == -1)
			continue;
		output += sprintf(output, "%u/", (unsigned char) path->bc[i]);
	}
	output += sprintf(output, "%u", (unsigned char) path->mod);
	return output;
}

/**
 * print_pa_hwpath - Returns hardware path for PA devices
 * dev: The device to return the path for
 * output: Pointer to a previously-allocated array to place the path in.
 *
 * This function fills in the output array with a human-readable path
 * to a PA device.  This string is compatible with that used by PDC, and
 * may be printed on the outside of the box.
 */
char *print_pa_hwpath(struct parisc_device *dev, char *output)
{
	struct hardware_path path;

	get_node_path(dev->parent, &path);
	path.mod = dev->hw_path;
	return print_hwpath(&path, output);
}


#if defined(CONFIG_PCI) || defined(CONFIG_ISA)
/**
 * get_pci_node_path - Returns hardware path for PCI devices
 * dev: The device to return the path for
 * output: Pointer to a previously-allocated array to place the path in.
 *
 * This function fills in the hardware_path structure with the route to
 * the specified PCI device.  This structure is suitable for passing to
 * PDC calls.
 */
void get_pci_node_path(struct pci_dev *dev, struct hardware_path *path)
{
	struct pci_bus *bus;
	const struct parisc_device *padev;
	int i = 5;

	memset(&path->bc, -1, 6);
	path->mod = PCI_FUNC(dev->devfn);
	path->bc[i--] = PCI_SLOT(dev->devfn);
	for (bus = dev->bus; bus->parent; bus = bus->parent) {
		unsigned int devfn = bus->self->devfn;
		path->bc[i--] = PCI_SLOT(devfn) | (PCI_FUNC(devfn) << 5);
	}

	padev = HBA_DATA(bus->sysdata)->dev;
	while (padev != &root) {
		path->bc[i--] = padev->hw_path;
		padev = padev->parent;
	}
}

/**
 * print_pci_hwpath - Returns hardware path for PCI devices
 * dev: The device to return the path for
 * output: Pointer to a previously-allocated array to place the path in.
 *
 * This function fills in the output array with a human-readable path
 * to a PCI device.  This string is compatible with that used by PDC, and
 * may be printed on the outside of the box.
 */
char *print_pci_hwpath(struct pci_dev *dev, char *output)
{
	struct hardware_path path;

	get_pci_node_path(dev, &path);
	return print_hwpath(&path, output);
}
#endif /* defined(CONFIG_PCI) || defined(CONFIG_ISA) */


struct parisc_device * create_tree_node(char id, struct parisc_device *parent,
		struct parisc_device **insert)
{
	struct parisc_device *dev = kmalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev)
		return NULL;
	memset(dev, 0, sizeof(*dev));
	dev->hw_path = id;
	dev->id.hw_type = HPHW_FAULTY;
	dev->parent = parent;
	dev->sibling = *insert;
	*insert = dev;
	return dev;
}

/**
 * alloc_tree_node - returns a device entry in the iotree
 * @parent: the parent node in the tree
 * @id: the element of the module path for this entry
 *
 * Checks all the children of @parent for a matching @id.  If none
 * found, it allocates a new device and returns it.
 */
struct parisc_device *
alloc_tree_node(struct parisc_device *parent, char id)
{
	struct parisc_device *prev;
	if ((!parent->child) || (parent->child->hw_path > id)) {
		return create_tree_node(id, parent, &parent->child);
	}

	prev = parent->child;
	if (prev->hw_path == id)
		return prev;

	while (prev->sibling && prev->sibling->hw_path < id) {
		prev = prev->sibling;
	}

	if ((prev->sibling) && (prev->sibling->hw_path == id))
		return prev->sibling;

	return create_tree_node(id, parent, &prev->sibling);
}

static struct parisc_device *find_parisc_device(struct hardware_path *modpath)
{
	int i;
	struct parisc_device *parent = &root;
	for (i = 0; i < 6; i++) {
		if (modpath->bc[i] == -1)
			continue;
		parent = alloc_tree_node(parent, modpath->bc[i]);
	}
	return alloc_tree_node(parent, modpath->mod);
}

struct parisc_device *
alloc_pa_dev(unsigned long hpa, struct hardware_path *mod_path)
{
	int status;
	unsigned long bytecnt;
	u8 iodc_data[32];
	struct parisc_device *dev;
	const char *name;

	/* Check to make sure this device has not already been added - Ryan */
	if (find_device_by_addr(hpa) != NULL)
		return NULL;

	status = pdc_iodc_read(&bytecnt, hpa, 0, &iodc_data, 32);
	if (status != PDC_OK)
		return NULL;

	dev = find_parisc_device(mod_path);
	if (dev->id.hw_type != HPHW_FAULTY) {
		char p[64];
		print_pa_hwpath(dev, p);
		printk("Two devices have hardware path %s.  Please file a bug with HP.\n"
			"In the meantime, you could try rearranging your cards.\n", p);
		return NULL;
	}

	dev->id.hw_type = iodc_data[3] & 0x1f;
	dev->id.hversion = (iodc_data[0] << 4) | ((iodc_data[1] & 0xf0) >> 4);
	dev->id.hversion_rev = iodc_data[1] & 0x0f;
	dev->id.sversion = ((iodc_data[4] & 0x0f) << 16) |
			(iodc_data[5] << 8) | iodc_data[6];
	dev->hpa = hpa;
	name = parisc_hardware_description(&dev->id);
	if (name) {
		strncpy(dev->name, name, sizeof(dev->name)-1);
	}

	return dev;
}

/**
 * register_parisc_device - Locate a driver to manage this device.
 * @dev: The parisc device.
 *
 * Search the driver list for a driver that is willing to manage
 * this device.
 */
int register_parisc_device(struct parisc_device *dev)
{
	struct parisc_driver *driver;

	if (!dev)
		return 0;

	if (dev->driver)
		return 1;
	
	spin_lock(&pa_lock);

	/* Locate a driver which agrees to manage this device.  */
	for (driver = pa_drivers; driver; driver = driver->next) {
		if (!match_device(driver,dev))
			continue;
		if (driver->probe(dev) == 0)
			break;
	}

	if (driver != NULL) {
		claim_device(driver, dev);
	}
	spin_unlock(&pa_lock);
	return driver != NULL;
}

#define BC_PORT_MASK 0x8
#define BC_LOWER_PORT 0x8

#define BUS_CONVERTER(dev) \
        ((dev->id.hw_type == HPHW_IOA) || (dev->id.hw_type == HPHW_BCPORT))

#define IS_LOWER_PORT(dev) \
        ((gsc_readl(&((struct bc_module *)dev->hpa)->io_status) \
                & BC_PORT_MASK) == BC_LOWER_PORT)

#define READ_IO_IO_LOW(dev) \
	(dev->id.hw_type == HPHW_IOA ? \
	        __raw_readl((unsigned long)&((struct bc_module *)dev->hpa)->io_io_low) << 16 : \
	        __raw_readl((unsigned long)&((struct bc_module *)dev->hpa)->io_io_low))

static void walk_native_bus(unsigned long addr, struct parisc_device *parent);
void walk_lower_bus(struct parisc_device *dev)
{

	if(!BUS_CONVERTER(dev) || IS_LOWER_PORT(dev))
		return;

	walk_native_bus((unsigned long)(signed int)READ_IO_IO_LOW(dev), dev);
}

#define MAX_NATIVE_DEVICES 64
#define NATIVE_DEVICE_OFFSET 0x1000

/**
 * walk_native_bus -- Probe a bus for devices
 * @addr: Base address of this bus.
 * 
 * A native bus (eg Runway or GSC) may have up to 64 devices on it,
 * spaced at intervals of 0x1000 bytes.  PDC may not inform us of these
 * devices, so we have to probe for them.  Unfortunately, we may find
 * devices which are not physically connected (such as extra serial &
 * keyboard ports).  This problem is not yet solved.
 */
static void walk_native_bus(unsigned long addr, struct parisc_device *parent)
{
	int i;
	struct hardware_path path;

	get_node_path(parent, &path);
	for (i = 0; i < MAX_NATIVE_DEVICES; i++) {
		unsigned long hpa = (addr + i * NATIVE_DEVICE_OFFSET);
		struct parisc_device *dev;

		/* Was the device already added by Firmware? */
		dev = find_device_by_addr(hpa);
		if (!dev) {
			path.mod = i;
			dev = alloc_pa_dev(hpa, &path);
			if (!dev)
				continue;

			register_parisc_device(dev);
		}
		walk_lower_bus(dev);
	}
}

#define CENTRAL_BUS_ADDR (unsigned long) 0xfffffffffff80000

/**
 * walk_central_bus - Find devices attached to the central bus
 *
 * PDC doesn't tell us about all devices in the system.  This routine
 * finds devices connected to the central bus.
 */
void walk_central_bus(void)
{
	walk_native_bus(CENTRAL_BUS_ADDR, &root);
}

void fixup_child_irqs(struct parisc_device *parent, int base,
			int (*choose_irq)(struct parisc_device *))
{
	struct parisc_device *dev;

	if (!parent->child)
		return;

	for (dev = check_dev(parent->child); dev; dev = dev->sibling) {
		int irq = choose_irq(dev);
		if (irq > 0) {
#ifdef __LP64__
			irq += 32;
#endif
			dev->irq = base + irq;
		}
	}
}

static void print_parisc_device(struct parisc_device *dev)
{
	char hw_path[64];
	static int count;

	print_pa_hwpath(dev, hw_path);
	printk(KERN_INFO "%d. %s (%d) at 0x%lx [%s], versions 0x%x, 0x%x, 0x%x",
		++count, dev->name, dev->id.hw_type, dev->hpa, hw_path,
		dev->id.hversion, dev->id.hversion_rev, dev->id.sversion);

	if (dev->num_addrs) {
		int k;
		printk(",  additional addresses: ");
		for (k = 0; k < dev->num_addrs; k++)
			printk("0x%lx ", dev->addr[k]);
	}
	printk("\n");
}

void print_subdevices(struct parisc_device *parent)
{
	struct parisc_device *dev;
	for (dev = parent->child; dev != parent->sibling; dev = next_dev(dev)) {
		print_parisc_device(dev);
	}
}

/**
 * print_parisc_devices - Print out a list of devices found in this system
 */
void print_parisc_devices(void)
{
	struct parisc_device *dev;
	for_each_padev(dev) {
		print_parisc_device(dev);
	}
}