Added remaining bus functions.

src/arch/i386/drivers/bus/bios_disks.c

@@ -1,18 +1,25 @@
 #include "realmode.h"
+#include "isa_ids.h"
+#include "bios_disks.h"
 
 #define CF ( 1 << 0 )
+#define BIOS_DISK_NONE 0
 
-struct disk_sector {
-	char data[512];
-};
+/*
+ * Ensure that there is sufficient space in the shared dev_bus
+ * structure for a struct bios_disk_device.
+ *
+ */
+DEV_BUS( struct bios_disk_device, bios_disk_dev );
+static char bios_disk_magic[0]; /* guaranteed unique symbol */
 
 /*
  * Reset the disk system using INT 13,0.  Forces both hard disks and
  * floppy disks to seek back to track 0.
  *
  */
-static void disk_init ( void ) {
-	REAL_EXEC ( rm_disk_init,
+void bios_disk_init ( void ) {
+	REAL_EXEC ( rm_bios_disk_init,
 		    "sti\n\t"
 		    "xorw %%ax,%%ax\n\t"
 		    "movb $0x80,%%dl\n\t"
@@ -28,16 +35,19 @@ static void disk_init ( void ) {
 /*
  * Read a single sector from a disk using INT 13,2.
  *
- * Returns the BIOS status code (%ah) - 0 indicates success
+ * Returns the BIOS status code (%ah) - 0 indicates success.
  *
  */
-static unsigned int pcbios_disk_read ( int drive, int cylinder, int head,
-				       int sector, struct disk_sector *buf ) {
+unsigned int bios_disk_read_once ( struct bios_disk_device *bios_disk,
+				   unsigned int cylinder,
+				   unsigned int head,
+				   unsigned int sector,
+				   struct bios_disk_sector *buf ) {
 	uint16_t basemem_buf, status, flags;
 	int discard_c, discard_d;
 
 	basemem_buf = BASEMEM_PARAMETER_INIT ( *buf );
-	REAL_EXEC ( rm_pcbios_disk_read,
+	REAL_EXEC ( rm_bios_disk_read,
 		    "sti\n\t"
 		    "movw $0x0201, %%ax\n\t" /* Read a single sector */
 		    "int $0x13\n\t"
@@ -46,14 +56,113 @@ static unsigned int pcbios_disk_read ( int drive, int cylinder, int head,
 		    "cli\n\t",
 		    4,
 		    OUT_CONSTRAINTS ( "=a" ( status ), "=b" ( flags ),
-				      "=c" ( discard_c ), "=d" ( discard_d ) ),
+				      "=c" ( discard_c ),
+				      "=d" ( discard_d ) ),
 		    IN_CONSTRAINTS ( "c" ( ( ( cylinder & 0xff ) << 8 ) |
 					   ( ( cylinder >> 8 ) & 0x3 ) |
 					   sector ),
-				     "d" ( ( head << 8 ) | drive ),
+				     "d" ( ( head << 8 ) | bios_disk->drive ),
 				     "b" ( basemem_buf ) ),
 		    CLOBBER ( "ebp", "esi", "edi" ) );
 	BASEMEM_PARAMETER_DONE ( *buf );
 
-	return ( flags & CF ) ? ( status >> 8 ) : 0;
+	return ( flags & CF ) ? ( status >> 8 ) : 0; 
+}
+
+/*
+ * Fill in parameters for a BIOS disk device based on drive number
+ *
+ */
+static int fill_bios_disk_device ( struct bios_disk_device *bios_disk ) {
+	uint16_t type, flags;
+       
+	REAL_EXEC ( rm_bios_disk_exists,
+		    "sti\n\t"
+		    "movb $0x15, %%ah\n\t"
+		    "int $0x13\n\t"
+		    "pushfw\n\t"
+		    "popw %%dx\n\t"
+		    "cli\n\t",
+		    2,
+		    OUT_CONSTRAINTS ( "=a" ( type ), "=d" ( flags ) ),
+		    IN_CONSTRAINTS ( "d" ( bios_disk->drive ) ),
+		    CLOBBER ( "ebx", "ecx", "esi", "edi", "ebp" ) );
+
+	if ( ( flags & CF ) ||
+	     ( ( type >> 8 ) == BIOS_DISK_NONE ) )
+		return 0;
+
+	DBG ( "BIOS disk found valid drive %hhx\n", bios_disk->drive );
+	return 1;
+}
+
+/*
+ * Find a BIOS disk device matching the specified driver
+ *
+ */
+int find_bios_disk_device ( struct bios_disk_device *bios_disk,
+			    struct bios_disk_driver *driver ) {
+
+	/* Initialise struct bios_disk if it's the first time it's been used.
+	 */
+	if ( bios_disk->magic != bios_disk_magic ) {
+		memset ( bios_disk, 0, sizeof ( *bios_disk ) );
+		bios_disk->magic = bios_disk_magic;
+	}
+
+	/* Iterate through all possible BIOS drives, starting where we
+	 * left off
+	 */
+	DBG ( "BIOS disk searching for device matching driver %s\n",
+	      driver->name );
+	do {
+		/* If we've already used this device, skip it */
+		if ( bios_disk->already_tried ) {
+			bios_disk->already_tried = 0;
+			continue;
+		}
+
+		/* Fill in device parameters */
+		if ( ! fill_bios_disk_device ( bios_disk ) ) {
+			continue;
+		}
+
+		/* Compare against driver's valid ID range */
+		if ( ( bios_disk->drive >= driver->min_drive ) &&
+		     ( bios_disk->drive <= driver->max_drive ) ) {
+			driver->fill_drive_name ( bios_disk->drive,
+						  bios_disk->name );
+			DBG ( "BIOS_DISK found drive %hhx (\"%s\") "
+			      "matching driver %s\n",
+			      bios_disk->drive, bios_disk->name,
+			      driver->name );
+			bios_disk->already_tried = 1;
+			return 1;
+		}
+	} while ( ++bios_disk->drive );
+
+	/* No device found */
+	DBG ( "BIOS disk found no device matching driver %s\n", driver->name );
+	return 0;
+}
+
+/*
+ * Find the next MCA device that can be used to boot using the
+ * specified driver.
+ *
+ */
+int find_bios_disk_boot_device ( struct dev *dev,
+				 struct bios_disk_driver *driver ) {
+	struct bios_disk_device *bios_disk
+		= ( struct bios_disk_device * ) dev->bus;
+
+	if ( ! find_bios_disk_device ( bios_disk, driver ) )
+		return 0;
+
+	dev->name = bios_disk->name;
+	dev->devid.bus_type = ISA_BUS_TYPE;
+	dev->devid.vendor_id = ISA_VENDOR ( 'D', 'S', 'K' );
+	dev->devid.device_id = bios_disk->drive;
+
+	return 1;
 }