Added a generalised ISA device-probing mechanism.

src/drivers/bus/isa.c

@@ -0,0 +1,123 @@
+#include "etherboot.h"
+#include "isa.h"
+
+/*
+ * isa.c implements a "classical" port-scanning method of ISA device
+ * detection.  The driver must provide a list of probe addresses
+ * (probe_addrs), together with a function (probe_addr) that can be
+ * used to test for the physical presence of a device at any given
+ * address.
+ *
+ * Note that this should probably be considered the "last resort" for
+ * device probing.  If the card supports ISAPnP or EISA, use that
+ * instead.  Some cards (e.g. the 3c509) implement a proprietary
+ * ISAPnP-like mechanism.
+ *
+ * The ISA probe address list can be overridden by config.c; if 
+ */
+
+/*
+ * Ensure that there is sufficient space in the shared dev_bus
+ * structure for a struct isa_device.
+ *
+ */
+DEV_BUS( struct isa_device, isa_dev );
+static char isa_magic[0]; /* guaranteed unique symbol */
+
+/*
+ * Find an ISA device matching the specified driver
+ *
+ */
+int find_isa_device ( struct isa_device *isa, struct isa_driver *driver ) {
+	unsigned int i;
+	uint16_t ioaddr;
+
+	/* Initialise struct isa if it's the first time it's been used. */
+	if ( isa->magic != isa_magic ) {
+		memset ( isa, 0, sizeof ( *isa ) );
+		isa->magic = isa_magic;
+	}
+
+	/* Iterate through any ISA probe addresses specified by
+	 * config.c, starting where we left off.
+	 */
+	for ( i = isa->probe_idx ; i < isa_extra_probe_addr_count ; i++ ) {
+		/* If we've already used this device, skip it */
+		if ( isa->already_tried ) {
+			isa->already_tried = 0;
+			continue;
+		}
+
+		/* Set I/O address */
+		ioaddr = isa_extra_probe_addrs[i].addr;
+
+		/* An I/O address of 0 in extra_probe_addrs list means
+		 * stop probing (i.e. don't continue to the
+		 * driver-provided list)
+		 */
+		if ( ! ioaddr )
+			goto notfound;
+
+		/* Use probe_addr method to see if there's a device
+		 * present at this address.
+		 */
+		if ( driver->probe_addr ( ioaddr ) ) {
+			isa->probe_idx = i;
+			goto found;
+		}
+	}
+
+	/* Iterate through all ISA probe addresses provided by the
+	 * driver, starting where we left off.
+	 */
+	for ( i = isa->probe_idx - isa_extra_probe_addr_count ;
+	      i < driver->addr_count ; i++ ) {
+
+		/* If we've already used this device, skip it */
+		if ( isa->already_tried ) {
+			isa->already_tried = 0;
+			continue;
+		}
+
+		/* Set I/O address */
+		ioaddr = driver->probe_addrs[i].addr;
+
+		/* Use probe_addr method to see if there's a device
+		 * present at this address.
+		 */
+		if ( driver->probe_addr ( ioaddr ) ) {
+			isa->probe_idx = i + isa_extra_probe_addr_count;
+			goto found;
+		}
+	}
+
+ notfound:
+	/* No device found */
+	isa->probe_idx = 0;
+	return 0;
+
+ found:
+	DBG ( "Found %s ISA device at address %hx\n", driver->name, ioaddr );
+	isa->ioaddr = ioaddr;
+	isa->already_tried = 1;
+	return 1;
+}
+
+/*
+ * Find the next ISA device that can be used to boot using the
+ * specified driver.
+ *
+ */
+int find_isa_boot_device ( struct dev *dev, struct isa_driver *driver ) {
+	struct isa_device *isa = ( struct isa_device * )dev->bus;
+
+	if ( ! find_isa_device ( isa, driver ) )
+		return 0;
+
+	dev->name = driver->name;
+	dev->devid.bus_type = ISA_BUS_TYPE;
+	dev->devid.vendor_id = driver->mfg_id;
+	dev->devid.device_id = driver->prod_id;
+
+	return 1;
+}