#ifndef DEV_H
#define DEV_H
#include "stdint.h"
#include "string.h"
#include <gpxe/buffer.h>
#include "dhcp.h" /* for dhcp_dev_id */
#include <gpxe/tables.h>
#include <assert.h>
/*
* Forward declarations
*
*/
struct type_dev;
struct type_driver;
struct bus_driver;
struct bus_dev;
struct device_driver;
/*
* When looking at the following data structures, mentally substitute
* "<bus>_" in place of "bus_" and everything will become clear.
* "struct bus_location" becomes "struct <bus>_location", which means
* "the location of a device on a <bus> bus", where <bus> is a
* particular type of bus such as "pci" or "isapnp".
*
*/
/*
* A physical device location on a bus.
*
*/
#define BUS_LOC_SIZE 8
struct bus_loc {
char bytes[BUS_LOC_SIZE];
};
/*
* A structure fully describing a physical device on a bus.
*
*/
#define BUS_DEV_SIZE 32
struct bus_dev {
char bytes[BUS_DEV_SIZE];
};
/*
* Individual buses will have different sizes for their <bus>_location
* and <bus>_device structures. We need to be able to allocate static
* storage that's large enough to contain these structures for any
* bus type that's being used in the current binary.
*
* We can't just create a union of all the various types, because some
* may be architecture-dependent (and some are even embedded in
* specific drivers, e.g. 3c509), so this would quickly get messy.
*
* We could use the magic of common symbols. Each bus could declare a
* common symbol with the name "_bus_dev" of the correct size; this
* is easily done using code like
* struct pci_device _bus_dev;
* The linker would then use the largest size of the "_bus_dev" symbol
* in any included object, thus giving us a single _bus_dev symbol of
* *exactly* the required size. However, there's no way to extract
* the size of this symbol, either directly as a linker symbol
* ("_bus_dev_size = SIZEOF(_bus_dev)"; the linker language just
* doesn't provide this construct) or via any linker trickery I can
* think of (such as creating a special common symbol section just for
* this symbol then using SIZE(section) to read the size of the
* section; ld recognises only a single common symbol section called
* "COMMON").
*
* Since there's no way to get the size of the symbol, this
* effectively limits us to just one instance of the symbol. This is
* all very well for the simple case of "just boot from any single
* device you can", but becomes limiting when you want to do things
* like introducing PCMCIA buses (which must instantiate other devices
* such as PCMCIA controllers).
*
* So, we declare the maximum sizes of these constructions to be
* compile-time constants. Each individual bus driver should define
* its own struct <bus>_location and struct <bus>_device however it
* likes, and can freely cast pointers from struct bus_loc to
* struct <bus>_location (and similarly for bus_dev). To guard
* against bounding errors, each bus driver *MUST* use the macros
* BUS_LOC_CHECK() and BUS_DEV_CHECK(), as in:
*
* BUS_LOC_CHECK ( struct pci_location );
* BUS_DEV_CHECK ( struct pci_device );
*
* These macros will generate a link-time error if the size of the
* <bus> structure exceeds the declared maximum size.
*
* The macros will generate no binary object code, but must be placed
* inside a function (in order to generate syntactically valid C).
* The easiest wy to do this is to place them in the
* <bus>_next_location() function.
*
* If anyone can think of a better way of doing this that avoids *ALL*
* of the problems described above, please implement it!
*
*/
#define BUS_LOC_CHECK(datatype) \
linker_assert( ( sizeof (datatype) <= sizeof (struct bus_loc) ), \
__BUS_LOC_SIZE_is_too_small__see_dev_h )
#define BUS_DEV_CHECK(datatype) \
linker_assert( ( sizeof (datatype) <= sizeof (struct bus_dev) ), \
__BUS_DEV_SIZE_is_too_small__see_dev_h )
/*
* Bus-level operations.
*
* int next_location ( struct bus_loc * bus_loc )
*
* Increment bus_loc to point to the next possible device on
* the bus (e.g. the next PCI busdevfn, or the next ISAPnP CSN).
* If there are no more valid locations, return 0 and leave
* struct bus_loc zeroed, otherwise return true.
*
* int fill_device ( struct bus_dev *bus_dev,
* struct bus_loc *bus_loc )
*
* Fill out a bus_dev structure with the parameters for the
* device at bus_loc. (For example, fill in the PCI vendor
* and device IDs). Return true if there is a device physically
* present at this location, otherwise 0.
*
* int check_driver ( struct bus_dev *bus_dev,
* struct device_driver *device_driver )
*
* Test whether or not the specified driver is capable of driving
* the specified device by, for example, comparing the device's
* PCI IDs against the list of PCI IDs claimed by the driver.
*
* char * describe ( struct bus_dev *bus_dev )
*
* Return a text string describing the bus device bus_dev
* (e.g. "PCI 00:01.2")
*
* char * name ( struct bus_dev *bus_dev )
*
* Return a text string describing the bus device bus_dev
* (e.g. "dfe538")
*
*/
struct bus_driver {
const char *name;
int ( *next_location ) ( struct bus_loc *bus_loc );
int ( *fill_device ) ( struct bus_dev *bus_dev,
struct bus_loc *bus_loc );
int ( *check_driver ) ( struct bus_dev *bus_dev,
struct device_driver *device_driver );
char * ( *describe_device ) ( struct bus_dev *bus_dev );
const char * ( *name_device ) ( struct bus_dev *bus_dev );
};
#define __bus_driver __table ( struct bus_driver, bus_driver, 01 )
/*
* A structure fully describing the bus-independent parts of a
* particular type (e.g. nic or disk) of device.
*
* Unlike struct bus_dev, e can limit ourselves to having no more than
* one instance of this data structure. We therefore place an
* instance in each type driver file (e.g. nic.c), and simply use a
* pointer to the struct type_dev in the struct dev.
*
*/
struct type_dev;
/*
* A type driver (e.g. nic, disk)
*
*/
struct type_driver {
char *name;
struct type_dev *type_dev; /* single instance */
char * ( * describe_device ) ( struct type_dev *type_dev );
int ( * configure ) ( struct type_dev *type_dev );
int ( * load ) ( struct type_dev *type_dev, struct buffer *buffer );
};
#define __type_driver __table ( struct type_driver, type_driver, 01 )
/*
* A driver for a device.
*
*/
struct device_driver {
const char *name;
struct type_driver *type_driver;
struct bus_driver *bus_driver;
struct bus_driver_info *bus_driver_info;
int ( * probe ) ( struct type_dev *type_dev,
struct bus_dev *bus_dev );
void ( * disable ) ( struct type_dev *type_dev,
struct bus_dev *bus_dev );
};
#define __device_driver __table ( struct device_driver, device_driver, 01 )
#if 0
#define DRIVER(_name,_type_driver,_bus_driver,_bus_info, \
_probe,_disable) \
struct device_driver device_ ## _bus_info __device_driver = { \
.name = _name, \
.type_driver = &_type_driver, \
.bus_driver = &_bus_driver, \
.bus_driver_info = ( struct bus_driver_info * ) &_bus_info, \
.probe = ( int (*) () ) _probe, \
.disable = ( void (*) () ) _disable, \
};
#endif
#define DRIVER(a,b,c,d,e,f)
/*
* A bootable device, comprising a physical device on a bus, a driver
* for that device, and a type device
*
*/
struct dev {
struct bus_driver *bus_driver;
struct bus_loc bus_loc;
struct bus_dev bus_dev;
struct device_driver *device_driver;
struct type_driver *type_driver;
struct type_dev *type_dev;
};
/* The current boot device */
extern struct dev dev;
/*
* Functions in dev.c
*
*/
extern void print_drivers ( void );
extern int find_any ( struct bus_driver **bus_driver, struct bus_loc *bus_loc,
struct bus_dev *bus_dev, signed int skip );
extern int find_by_device ( struct device_driver **device_driver,
struct bus_driver *bus_driver,
struct bus_dev *bus_dev,
signed int skip );
extern int find_by_driver ( struct bus_loc *bus_loc, struct bus_dev *bus_dev,
struct device_driver *device_driver,
signed int skip );
extern int find_any_with_driver ( struct dev *dev, signed int skip );
/*
* Functions inlined to save space
*
*/
/* Probe a device */
static inline int probe ( struct dev *dev ) {
return dev->device_driver->probe ( dev->type_dev, &dev->bus_dev );
}
/* Disable a device */
static inline void disable ( struct dev *dev ) {
dev->device_driver->disable ( dev->type_dev, &dev->bus_dev );
}
/* Set the default boot device */
static inline void select_device ( struct dev *dev,
struct bus_driver *bus_driver,
struct bus_loc *bus_loc ) {
dev->bus_driver = bus_driver;
memcpy ( &dev->bus_loc, bus_loc, sizeof ( dev->bus_loc ) );
}
/* Configure a device */
static inline int configure ( struct dev *dev ) {
return dev->type_driver->configure ( dev->type_dev );
}
/* Boot from a device */
static inline int load ( struct dev *dev, struct buffer *buffer ) {
return dev->type_driver->load ( dev->type_dev, buffer );
}
#endif /* DEV_H */
