ISA Plug & Play support by Jaroslav Kysela <perex@suse.cz>
==========================================================

Interface /proc/isapnp
======================

Read commands:
--------------

No comment.

Write commands:
---------------

With the write interface you can activate or modify the configuration of
ISA Plug & Play devices.  It is mainly useful for drivers which have not
been rewritten to use the ISA Plug & Play kernel support yet.

card <idx> <vendor>	- select PnP device by vendor identification
csn <CSN>		- select PnP device by CSN
dev <idx> <logdev>	- select logical device
auto			- run autoconfigure
activate		- activate logical device
deactivate		- deactivate logical device
port <idx> <value>	- set port 0-7 to value
irq <idx> <value>	- set IRQ 0-1 to value
dma <idx> <value>	- set DMA 0-1 to value
memory <idx> <value>	- set memory 0-3 to value
poke <reg> <value>	- poke configuration byte to selected register
pokew <reg> <value>	- poke configuration word to selected register
poked <reg> <value>	- poke configuration dword to selected register
allow_dma0 <value>	- allow dma channel 0 during auto activation: 0=off, 1=on

Explanation:
	- variable <idx> begins with zero
	- variable <CSN> begins with one
	- <vendor> is in the standard format 'ABC1234'
	- <logdev> is in the standard format 'ABC1234'

Example:

cat > /proc/isapnp <<EOF
card 0 CSC7537
dev 0 CSC0000
port 0 0x534
port 1 0x388
port 2 0x220
irq 0 5
dma 0 1
dma 1 3
poke 0x70 9
activate
logdev 0 CSC0001
port 0 0x240
activate
EOF


Information for developers
==========================

Finding a device
----------------

extern struct pci_bus *isapnp_find_card(unsigned short vendor,
                                        unsigned short device,
                                        struct pci_bus *from);

This function finds an ISA PnP card.  For the vendor argument, the
ISAPNP_VENDOR(a,b,c) macro should be used, where a,b,c are characters or
integers.  For the device argument the ISAPNP_DEVICE(x) macro should be
used, where x is an integer value.  Both vendor and device arguments
can be taken from contents of the /proc/isapnp file.

extern struct pci_dev *isapnp_find_dev(struct pci_bus *card,
                                       unsigned short vendor,
                                       unsigned short function,
                                       struct pci_dev *from);

This function finds an ISA PnP device. If card is NULL, then the global
search mode is used (all devices are used for the searching).  Otherwise
only devices which belong to the specified card are checked.  For the
function number the ISAPNP_FUNCTION(x) macro can be used; it works
similarly to the ISAPNP_DEVICE(x) macro.

extern int isapnp_probe_cards(const struct isapnp_card_id *ids,
                              int (*probe)(struct pci_bus *card,
                              const struct isapnp_card_id *id));


This function is a helper for drivers which need to use more than
one device from an ISA PnP card.  The probe callback is called with
appropriate arguments for each card.

Example for ids parameter initialization:

static struct isapnp_card_id card_ids[] __devinitdata = {
	{
        	ISAPNP_CARD_ID('A','D','V', 0x550a),
                devs: {
			ISAPNP_DEVICE_ID('A', 'D', 'V', 0x0010),
			ISAPNP_DEVICE_ID('A', 'D', 'V', 0x0011)
		},
		driver_data: 0x1234,
	},
	{
		ISAPNP_CARD_END,
	}
};
ISAPNP_CARD_TABLE(card_ids);

extern int isapnp_probe_devs(const struct isapnp_device_id *ids,
                             int (*probe)(struct pci_bus *card,
                             const struct isapnp_device_id *id));


This function is a helper for drivers which need to use one
device from an ISA PnP card.  The probe callback is called with
appropriate arguments for each matched device.

Example for ids parameter initialization:

static struct isapnp_device_id device_ids[] __devinitdata = {
	{ ISAPNP_DEVICE_SINGLE('E','S','S', 0x0968, 'E','S','S', 0x0968), },
	{ ISAPNP_DEVICE_SINGLE_END, }
};
MODULE_DEVICE_TABLE(isapnp, device_ids);


ISA PnP configuration
=====================

There are two ways in which the ISA PnP interface can be used.

First way: low-level
--------------------

All ISA PNP configuration registers are accessible via the low-level
isapnp_(read|write)_(byte|word|dword) functions.

The function isapnp_cfg_begin() must be called before any lowlevel function.
The function isapnp_cfg_end() must be always called after configuration
otherwise the access to the ISA PnP configuration functions will be blocked.

Second way: auto-configuration
------------------------------

This feature gives to the driver the real power of the ISA PnP driver.
The function dev->prepare() initializes the resource members in the device
structure.  This structure contains all resources set to auto configuration
values after the initialization.  The device driver may modify some resources
to skip the auto configuration for a given resource.

Once the device structure contains all requested resource values, the function
dev->activate() must be called to assign free resources to resource members
with the auto configuration value.

Function dev->activate() does:
   - resources with the auto configuration value are configured
   - the auto configuration is created using ISA PnP resource map
   - the function writes configuration to ISA PnP configuration registers
   - the function returns to the caller actual used resources

When the device driver is removed, function dev->deactivate() has to be
called to free all assigned resources.

Example (game port initialization)
==================================

/*** initialization ***/

	struct pci_dev *dev;

	/* find the first game port, use standard PnP IDs */
	dev = isapnp_find_dev(NULL,
			      ISAPNP_VENDOR('P','N','P'),
			      ISAPNP_FUNCTION(0xb02f),
			      NULL);
	if (!dev)
		return -ENODEV;
	if (dev->active)
		return -EBUSY;
	if (dev->prepare(dev)<0)
		return -EAGAIN;
	if (!(dev->resource[0].flags & IORESOURCE_IO))
		return -ENODEV;
	if (!dev->ro) {
		/* override resource */
		if (user_port != USER_PORT_AUTO_VALUE)
			isapnp_resource_change(&dev->resource[0], user_port, 1);
	}
	if (dev->activate(dev)<0) {
		printk("isapnp configure failed (out of resources?)\n");
		return -ENOMEM;
	}
	user_port = dev->resource[0].start;		/* get real port */

/*** deactivation ***/

	/* to deactivate use: */
 	if (dev)
 		dev->deactivate(dev);
