drivers.c

底层驱动开发

/*
 * 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]>
 * Copyright (c) 2001,2002 Ryan Bradetich 
 * Copyright (c) 2004-2005 Thibaut VARENE <[e-mail]>
 * 
 * The file handles registering devices and drivers, then matching them.
 * It's the closest we get to a dating agency.
 *
 * If you're thinking about modifying this file, here are some gotchas to
 * bear in mind:
 *  - 715/Mirage device paths have a dummy device between Lasi and its children
 *  - The EISA adapter may show up as a sibling or child of Wax
 *  - Dino has an optionally functional serial port.  If firmware enables it,
 *    it shows up as a child of Dino.  If firmware disables it, the buswalk
 *    finds it and it shows up as a child of Cujo
 *  - Dino has both parisc and pci devices as children
 *  - parisc devices are discovered in a random order, including children
 *    before parents in some cases.
 */

#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/parisc-device.h>

/* See comments in include/asm-parisc/pci.h */
struct hppa_dma_ops *hppa_dma_ops;
EXPORT_SYMBOL(hppa_dma_ops);

static struct device root = {
	.bus_id = "parisc",
};

#define for_each_padev(padev) \
	for (padev = next_dev(&root); padev != NULL; \
			padev = next_dev(&padev->dev))

#define check_dev(padev) \
	(padev->id.hw_type != HPHW_FAULTY) ? padev : next_dev(&padev->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.
 */
static struct parisc_device *next_dev(struct device *dev)
{
	if (!list_empty(&dev->children)) {
		dev = list_to_dev(dev->children.next);
		return check_dev(to_parisc_device(dev));
	}

	while (dev != &root) {
		if (dev->node.next != &dev->parent->children) {
			dev = list_to_dev(dev->node.next);
			return to_parisc_device(dev);
		}
		dev = dev->parent;
	}

	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);
}

static int parisc_driver_probe(struct device *dev)
{
	int rc;
	struct parisc_device *pa_dev = to_parisc_device(dev);
	struct parisc_driver *pa_drv = to_parisc_driver(dev->driver);

	rc = pa_drv->probe(pa_dev);

	if(!rc)
		claim_device(pa_drv, pa_dev);

	return rc;
}

static int parisc_driver_remove(struct device *dev)
{
	struct parisc_device *pa_dev = to_parisc_device(dev);
	struct parisc_driver *pa_drv = to_parisc_driver(dev->driver);
	if (pa_drv->remove)
		pa_drv->remove(pa_dev);
	release_mem_region(pa_dev->hpa, 0x1000);

	return 0;
}
	

/**
 * 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)
{
	/* FIXME: we need this because apparently the sti
	 * driver can be registered twice */
	if(driver->drv.name) {
		printk(KERN_WARNING 
		       "BUG: skipping previously registered driver %s\n",
		       driver->name);
		return 1;
	}

	if (!driver->probe) {
		printk(KERN_WARNING 
		       "BUG: driver %s has no probe routine\n",
		       driver->name);
		return 1;
	}

	driver->drv.bus = &parisc_bus_type;

	/* We install our own probe and remove routines */
	WARN_ON(driver->drv.probe != NULL);
	WARN_ON(driver->drv.remove != NULL);

	driver->drv.probe = parisc_driver_probe;
	driver->drv.remove = parisc_driver_remove;
	driver->drv.name = driver->name;

	return driver_register(&driver->drv);
}
EXPORT_SYMBOL(register_parisc_driver);

/**
 * 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)
{
	driver_unregister(&driver->drv);
	return 0;
}
EXPORT_SYMBOL(unregister_parisc_driver);

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 *padev, int type)
{
	const struct device *dev = &padev->dev;
	while (dev != &root) {
		struct parisc_device *candidate = to_parisc_device(dev);
		if (candidate->id.hw_type == type)
			return candidate;
		dev = dev->parent;
	}

	return NULL;
}

#ifdef CONFIG_PCI
static inline int is_pci_dev(struct device *dev)
{
	return dev->bus == &pci_bus_type;
}
#else
static inline int is_pci_dev(struct device *dev)
{
	return 0;
}
#endif

/*
 * get_node_path fills in @path with the firmware path to the device.
 * Note that if @node is a parisc device, we don't fill in the 'mod' field.
 * This is because both callers pass the parent and fill in the mod
 * themselves.  If @node is a PCI device, we do fill it in, even though this
 * is inconsistent.
 */
static void get_node_path(struct device *dev, struct hardware_path *path)
{
	int i = 5;
	memset(&path->bc, -1, 6);

	if (is_pci_dev(dev)) {
		unsigned int devfn = to_pci_dev(dev)->devfn;
		path->mod = PCI_FUNC(devfn);
		path->bc[i--] = PCI_SLOT(devfn);
		dev = dev->parent;
	}

	while (dev != &root) {
		if (is_pci_dev(dev)) {
			unsigned int devfn = to_pci_dev(dev)->devfn;
			path->bc[i--] = PCI_SLOT(devfn) | (PCI_FUNC(devfn)<< 5);
		} else if (dev->bus == &parisc_bus_type) {
			path->bc[i--] = to_parisc_device(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->dev.parent, &path);
	path.mod = dev->hw_path;
	return print_hwpath(&path, output);
}
EXPORT_SYMBOL(print_pa_hwpath);

#if defined(CONFIG_PCI) || defined(CONFIG_ISA)
/**
 * get_pci_node_path - Determines the hardware path for a PCI device
 * @pdev: The device to return the path for
 * @path: 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 *pdev, struct hardware_path *path)
{
	get_node_path(&pdev->dev, path);
}
EXPORT_SYMBOL(get_pci_node_path);

/**
 * 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);
}
EXPORT_SYMBOL(print_pci_hwpath);

#endif /* defined(CONFIG_PCI) || defined(CONFIG_ISA) */

static void setup_bus_id(struct parisc_device *padev)
{
	struct hardware_path path;
	char *output = padev->dev.bus_id;
	int i;

	get_node_path(padev->dev.parent, &path);

	for (i = 0; i < 6; i++) {
		if (path.bc[i] == -1)
			continue;
		output += sprintf(output, "%u:", (unsigned char) path.bc[i]);
	}
	sprintf(output, "%u", (unsigned char) padev->hw_path);
}

struct parisc_device * create_tree_node(char id, struct device *parent)
{
	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->dev.parent = parent;
	setup_bus_id(dev);

	dev->dev.bus = &parisc_bus_type;
	dev->dma_mask = 0xffffffffUL;	/* PARISC devices are 32-bit */

	/* make the generic dma mask a pointer to the parisc one */
	dev->dev.dma_mask = &dev->dma_mask;