*
***************************************************************************/
-#include "string.h"
-#include "timer.h"
-#include "io.h"
-#include "console.h"
-#include "isapnp.h"
-
-/*
- * We can have only one ISAPnP bus in a system. Once the read port is
- * known and all cards have been allocated CSNs, there's nothing to be
- * gained by re-scanning for cards.
+/** @file
+ *
+ * ISAPnP bus support
+ *
+ * Etherboot orignally gained ISAPnP support in a very limited way for
+ * the 3c515 NIC. The current implementation is almost a complete
+ * rewrite based on the ISAPnP specification, with passing reference
+ * to the Linux ISAPnP code.
+ *
+ * There can be only one ISAPnP bus in a system. Once the read port
+ * is known and all cards have been allocated CSNs, there's nothing to
+ * be gained by re-scanning for cards.
*
* However, we shouldn't make scanning the ISAPnP bus an INIT_FN(),
* because even ISAPnP probing can still screw up other devices on the
* an ISAPnP device.
*
* External code (e.g. the ISAPnP ROM prefix) may already know the
- * read port address, in which case it can initialise this value.
- * Note that setting the read port address will prevent further
- * isolation from taking place; you should set the read port address
- * only if you know that devices have already been allocated CSNs.
+ * read port address, in which case it can store it in @c
+ * isapnp_read_port. Note that setting the read port address in this
+ * way will prevent further isolation from taking place; you should
+ * set the read port address only if you know that devices have
+ * already been allocated CSNs.
+ *
+ */
+
+#include "string.h"
+#include "timer.h"
+#include "io.h"
+#include "console.h"
+#include "isapnp.h"
+
+/**
+ * ISAPnP Read Port address.
*
*/
uint16_t isapnp_read_port;
-/*
+/**
* Highest assigned CSN.
*
- * Note that *we* do not necessarily assign CSNs; it could be done by
+ * Note that @b we do not necessarily assign CSNs; it could be done by
* the PnP BIOS instead. We therefore set this only when we first try
* to Wake[CSN] a device and find that there's nothing there. Page 16
* (PDF page 22) of the ISAPnP spec states that "Valid Card Select
+ isapnp_read_byte ( address + 1 ) );
}
+/** Inform cards of a new read port address */
static inline void isapnp_set_read_port ( void ) {
isapnp_write_byte ( ISAPNP_READPORT, isapnp_read_port >> 2 );
}
+/**
+ * Enter the Isolation state.
+ *
+ * Only cards currently in the Sleep state will respond to this
+ * command.
+ *
+ */
static inline void isapnp_serialisolation ( void ) {
isapnp_write_address ( ISAPNP_SERIALISOLATION );
}
+/**
+ * Enter the Wait for Key state.
+ *
+ * All cards will respond to this command, regardless of their current
+ * state.
+ *
+ */
static inline void isapnp_wait_for_key ( void ) {
isapnp_write_byte ( ISAPNP_CONFIGCONTROL, ISAPNP_CONFIG_WAIT_FOR_KEY );
}
+/**
+ * Reset (i.e. remove) Card Select Number.
+ *
+ * Only cards currently in the Sleep state will respond to this
+ * command.
+ *
+ */
static inline void isapnp_reset_csn ( void ) {
isapnp_write_byte ( ISAPNP_CONFIGCONTROL, ISAPNP_CONFIG_RESET_CSN );
}
+/**
+ * Place a specified card into the Config state.
+ *
+ * @v csn Card Select Number
+ * @ret None
+ * @err None
+ *
+ * Only cards currently in the Sleep, Isolation, or Config states will
+ * respond to this command. The card that has the specified CSN will
+ * enter the Config state, all other cards will enter the Sleep state.
+ *
+ */
static inline void isapnp_wake ( uint8_t csn ) {
isapnp_write_byte ( ISAPNP_WAKE, csn );
}
return isapnp_read_byte ( ISAPNP_STATUS );
}
+/**
+ * Assign a Card Select Number to a card, and enter the Config state.
+ *
+ * @v csn Card Select Number
+ * @ret None
+ * @err None
+ *
+ * Only cards in the Isolation state will respond to this command.
+ * The isolation protocol is designed so that only one card will
+ * remain in the Isolation state by the time the isolation protocol
+ * completes.
+ *
+ */
static inline void isapnp_write_csn ( uint8_t csn ) {
isapnp_write_byte ( ISAPNP_CARDSELECTNUMBER, csn );
}
udelay ( 1000 );
}
-/*
- * The linear feedback shift register as described in Appendix B of
- * the PnP ISA spec. The hardware implementation uses eight D-type
- * latches and two XOR gates. I think this is probably the smallest
- * possible implementation in software. Six instructions when input_bit
- * is a constant 0 (for isapnp_send_key). :)
+/**
+ * Linear feedback shift register.
+ *
+ * @v lfsr Current value of the LFSR
+ * @v input_bit Current input bit to the LFSR
+ * @ret lfsr Next value of the LFSR
+ * @err None
+ *
+ * This routine implements the linear feedback shift register as
+ * described in Appendix B of the PnP ISA spec. The hardware
+ * implementation uses eight D-type latches and two XOR gates. I
+ * think this is probably the smallest possible implementation in
+ * software. Six instructions when input_bit is a constant 0 (for
+ * isapnp_send_key). :)
*
*/
static inline uint8_t isapnp_lfsr_next ( uint8_t lfsr, int input_bit ) {
return lfsr_next;
}
-/*
- * Send the ISAPnP initiation key
+/**
+ * Send the ISAPnP initiation key.
+ *
+ * Sending the key causes all ISAPnP cards that are currently in the
+ * Wait for Key state to transition into the Sleep state.
*
*/
static void isapnp_send_key ( void ) {
}
}
-/*
- * Compute ISAPnP identifier checksum
+/**
+ * Compute ISAPnP identifier checksum
+ *
+ * @v identifier ISAPnP identifier
+ * @ret checksum Expected checksum value
+ * @err None
*
*/
static uint8_t isapnp_checksum ( struct isapnp_identifier *identifier ) {
return 0xff;
}
-/*
- * Read n bytes of resource data from the current location. If buf is
- * NULL, discard data.
+/**
+ * Read resource data.
+ *
+ * @v buf Buffer in which to store data, or NULL
+ * @v bytes Number of bytes to read
+ * @ret None
+ * @err None
+ *
+ * Resource data is read from the current location. If @c buf is NULL,
+ * the data is discarded.
*
*/
static void isapnp_peek ( uint8_t *buf, size_t bytes ) {
}
}
-/*
- * Scan through the resource data until we find a particular tag, and
- * read its contents into a buffer.
+/**
+ * Find a tag within the resource data.
*
- * It is the caller's responsibility to ensure that buf is large
- * enough to contain a tag of the requested size.
+ * @v wanted_tag The tag that we're looking for
+ * @v buf Buffer in which to store the tag's contents
+ * @ret True Tag was found
+ * @ret False Tag was not found
+ * @err None
+ *
+ * Scan through the resource data until we find a particular tag, and
+ * read its contents into a buffer. It is the caller's responsibility
+ * to ensure that @c buf is large enough to contain a tag of the
+ * requested size.
*
*/
static int isapnp_find_tag ( uint8_t wanted_tag, uint8_t *buf ) {
return 0;
}
-/*
- * Try isolating ISAPnP cards at the current read port. Return the
- * number of ISAPnP cards found. <0 indicates "try a new read port",
- * 0 indicates "definitely no cards".
+/**
+ * Try isolating ISAPnP cards at the current read port.
+ *
+ * @ret \>0 Number of ISAPnP cards found
+ * @ret 0 There are no ISAPnP cards in the system
+ * @ret \<0 A conflict was detected; try a new read port
+ * @err None
*
* The state diagram on page 18 (PDF page 24) of the PnP ISA spec
* gives the best overview of what happens here.
return csn;
}
-/*
- * Isolate all ISAPnP cards, locating a valid read port in the process.
+/**
+ * Find a valid read port and isolate all ISAPnP cards.
*
*/
static void isapnp_isolate ( void ) {
}
}
-/*
- * Increment a bus_loc structure to the next possible ISAPnP location.
- * Leave the structure zeroed and return 0 if there are no more valid
- * locations.
+/**
+ * Increment a @c bus_loc structure to the next possible ISAPnP
+ * location.
+ *
+ * @v bus_loc Bus location
+ * @ret True @c bus_loc contains a valid ISAPnP location
+ * @ret False There are no more valid ISAPnP locations
+ * @err None
+ *
+ * If there are no more valid locations, the @c bus_loc structure will
+ * be zeroed.
*
*/
static int isapnp_next_location ( struct bus_loc *bus_loc ) {
return ( ++isapnp_loc->logdev ? 1 : ++isapnp_loc->csn );
}
-/*
- * Fill in parameters for an ISAPnP device based on CSN
+/**
+ * Fill in parameters for an ISAPnP device based on CSN.
*
- * Return 1 if device present, 0 otherwise
+ * @v bus_dev Bus device to be filled in
+ * @v bus_loc Bus location as filled in by isapnp_next_location()
+ * @ret True A device is present at this location
+ * @ret False No device is present at this location
+ * @err None
*
*/
static int isapnp_fill_device ( struct bus_dev *bus_dev,
return 1;
}
-/*
+/**
* Test whether or not a driver is capable of driving the device.
*
+ * @v bus_dev Bus device as filled in by isapnp_fill_device()
+ * @v device_driver Device driver
+ * @ret True Driver is capable of driving this device
+ * @ret False Driver is not capable of driving this device
+ * @err None
+ *
*/
static int isapnp_check_driver ( struct bus_dev *bus_dev,
struct device_driver *device_driver ) {
return 0;
}
-/*
- * Describe an ISAPnP device
+/**
+ * Describe an ISAPnP device.
+ *
+ * @v bus_dev Bus device as filled in by isapnp_fill_device()
+ * @ret string Printable string describing the device
+ * @err None
+ *
+ * The string returned by isapnp_describe_device() is valid only until
+ * the next call to isapnp_describe_device().
*
*/
static char * isapnp_describe_device ( struct bus_dev *bus_dev ) {
return isapnp_description;
}
-/*
- * Name an ISAPnP device
+/**
+ * Name an ISAPnP device.
+ *
+ * @v bus_dev Bus device as filled in by isapnp_fill_device()
+ * @ret string Printable string naming the device
+ * @err None
+ *
+ * The string returned by isapnp_name_device() is valid only until the
+ * next call to isapnp_name_device().
*
*/
static const char * isapnp_name_device ( struct bus_dev *bus_dev ) {
.name_device = isapnp_name_device,
};
-/*
- * Activate or deactivate an ISAPnP device
+/**
+ * Activate or deactivate an ISAPnP device.
+ *
+ * @v isapnp ISAPnP device
+ * @v activation True to enable, False to disable the device
+ * @ret None
+ * @err None
*
* This routine simply activates the device in its current
- * configuration. It does not attempt any kind of resource
- * arbitration.
+ * configuration, or deactivates the device. It does not attempt any
+ * kind of resource arbitration.
*
*/
void isapnp_device_activation ( struct isapnp_device *isapnp,
isapnp->csn, isapnp->logdev );
}
-/*
- * Fill in a nic structure
+/**
+ * Fill in a nic structure.
+ *
+ * @v nic NIC structure to be filled in
+ * @v isapnp ISAPnP device
+ * @ret None
+ * @err None
+ *
+ * This fills in generic NIC parameters (e.g. I/O address and IRQ
+ * number) that can be determined directly from the ISAPnP device,
+ * without any driver-specific knowledge.
*
*/
void isapnp_fill_nic ( struct nic *nic, struct isapnp_device *isapnp ) {
http://git.etherboot.org / people / xl0 / gpxe.git / blobdiff