[PATCH] Add PC-9800 bios parameter support in SCSI

James' scsi tree already contains an big update to wd33c93 that will make
integrating pc980155 a lot easier - it will hopefully appear in 2.5.63.

I've done some more work on the bios parameter stuff, this is the patch
I came up with, James can you merge it into the linux-scsi tree?  It just
adds a new file for pc98-style bios geometry to the scsi core.

drivers/scsi/Makefile

@@ -120,13 +120,11 @@ obj-$(CONFIG_BLK_DEV_SD)	+= sd_mod.o
 obj-$(CONFIG_BLK_DEV_SR)	+= sr_mod.o
 obj-$(CONFIG_CHR_DEV_SG)	+= sg.o
 
-scsi_mod-objs	:= scsi.o hosts.o scsi_ioctl.o constants.o scsicam.o \
-		   scsi_error.o scsi_lib.o scsi_scan.o scsi_syms.o \
-		   scsi_sysfs.o
-
-ifdef CONFIG_PROC_FS
-scsi_mod-objs	+= scsi_proc.o
-endif
+scsi_mod-y			+= scsi.o hosts.o scsi_ioctl.o constants.o \
+				   scsicam.o scsi_error.o scsi_lib.o \
+				   scsi_scan.o scsi_syms.o scsi_sysfs.o
+scsi_mod-$(CONFIG_PROC_FS)	+= scsi_proc.o
+scsi_mod-$(CONFIG_X86_PC9800)	+= scsi_pc98.o
 			
 sd_mod-objs	:= sd.o
 sr_mod-objs	:= sr.o sr_ioctl.o sr_vendor.o

drivers/scsi/scsi_pc98.c

+/*
+ *  Copyright (C) 2003  Osamu Tomita <tomita@cinet.co.jp>
+ *
+ *  PC9801 BIOS geometry handling.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/genhd.h>
+#include <linux/blk.h>
+#include <asm/pc9800.h>
+
+#include "scsi.h"
+#include "hosts.h"
+
+
+/* XXX - For now, we assume the first (i.e. having the least host_no)
+   real (i.e. non-emulated) host adapter shall be BIOS-controlled one.
+   We *SHOULD* invent another way.  */
+static inline struct Scsi_Host *first_real_host(void)
+{
+	struct Scsi_Host *shost = NULL;
+
+	while ((shost = scsi_host_get_next(shost))) {
+		if (!shost->hostt->emulated)
+			break;
+	}
+
+	return shost;
+}
+
+static int pc98_first_bios_param(struct scsi_device *sdev, int *ip)
+{
+	const u8 *p = (&__PC9800SCA(u8, PC9800SCA_SCSI_PARAMS) + sdev->id * 4);
+
+	ip[0] = p[1];   /* # of heads */
+	ip[1] = p[0];   /* # of sectors/track */
+	ip[2] = *(u16 *)&p[2] & 0x0fff; /* # of cylinders */
+	if (p[3] & (1 << 6)) { /* #-of-cylinders is 16-bit */
+		ip[2] |= (ip[0] & 0xf0) << 8;
+		ip[0] &= 0x0f;
+	}
+
+	return 0;
+}
+
+int pc98_bios_param(struct scsi_device *sdev, struct block_device *bdev,
+			sector_t capacity, int *ip)
+{
+	static struct Scsi_Host *first_real = first_real_host();
+
+	if (sdev->host == first_real && sdev->id < 7 &&
+	    __PC9800SCA_TEST_BIT(PC9800SCA_DISK_EQUIPS, sdev->id))
+	    	return pc98_first_bios_param(sdev, ip);
+
+	/* Assume PC-9801-92 compatible parameters for HAs without BIOS.  */
+	ip[0] = 8;
+	ip[1] = 32;
+	ip[2] = capacity / (8 * 32);
+	if (ip[2] > 65535) {    /* if capacity >= 8GB */
+		/* Recent on-board adapters seem to use this parameter. */
+		ip[1] = 128;
+		ip[2] = capacity / (8 * 128);
+		if (ip[2] > 65535) { /* if capacity >= 32GB  */
+			/* Clip the number of cylinders.  Currently
+			   this is the limit that we deal with.  */
+			ip[2] = 65535;
+		}
+	}
+
+	return 0;
+}
+
+EXPORT_SYMBOL(pc98_bios_param);