block: delete super ancient PC-XT driver for 1980's hardware

This driver was for the 8 bit ISA cards that were installed in
the PC-XT machines of 1980 vintage.  They supported the dual
ribbon cable MFM drives of 10-20MB capacity, and ran at a 3:1
interleave, giving performance on the order of 128kB/s.

By the introduction of the PC-AT (286) these controllers were
already scrapped in favour of 16 bit controllers with some onboard
RAM that could support a 1:1 interleave.

The git history doesn't show any evidence of runtime fixes that
would reflect active usage; instead just the usual tree-wide API
type changes/cleanups.  Going back to in-source changelogs, the
last "runtime" fix that is evident is something I did over a
dozen years ago[1] -- and even back then, the hardware was long
since unavailable, so that ancient fix was also not runtime tested.

The time is long overdue for this to get flushed, so lets get
rid of it before anyone wastes more time doing builds and sparse
checks etc. on long since dead code.

[1] http://lkml.indiana.edu/hypermail/linux/kernel/0102.2/0027.htmlSigned-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

drivers/block/Kconfig

@@ -63,19 +63,6 @@ config AMIGA_Z2RAM
 	  To compile this driver as a module, choose M here: the
 	  module will be called z2ram.
 
-config BLK_DEV_XD
-	tristate "XT hard disk support"
-	depends on ISA && ISA_DMA_API
-	select CHECK_SIGNATURE
-	help
-	  Very old 8 bit hard disk controllers used in the IBM XT computer
-	  will be supported if you say Y here.
-
-	  To compile this driver as a module, choose M here: the
-	  module will be called xd.
-
-	  It's pretty unlikely that you have one of these: say N.
-
 config GDROM
 	tristate "SEGA Dreamcast GD-ROM drive"
 	depends on SH_DREAMCAST

drivers/block/Makefile

@@ -15,7 +15,6 @@ obj-$(CONFIG_ATARI_FLOPPY)	+= ataflop.o
 obj-$(CONFIG_AMIGA_Z2RAM)	+= z2ram.o
 obj-$(CONFIG_BLK_DEV_RAM)	+= brd.o
 obj-$(CONFIG_BLK_DEV_LOOP)	+= loop.o
-obj-$(CONFIG_BLK_DEV_XD)	+= xd.o
 obj-$(CONFIG_BLK_CPQ_DA)	+= cpqarray.o
 obj-$(CONFIG_BLK_CPQ_CISS_DA)  += cciss.o
 obj-$(CONFIG_BLK_DEV_DAC960)	+= DAC960.o

drivers/block/xd.h

-#ifndef _LINUX_XD_H
-#define _LINUX_XD_H
-
-/*
- * This file contains the definitions for the IO ports and errors etc. for XT hard disk controllers (at least the DTC 5150X).
- *
- * Author: Pat Mackinlay, pat@it.com.au
- * Date: 29/09/92
- *
- * Revised: 01/01/93, ...
- *
- * Ref: DTC 5150X Controller Specification (thanks to Kevin Fowler, kevinf@agora.rain.com)
- * Also thanks to: Salvador Abreu, Dave Thaler, Risto Kankkunen and Wim Van Dorst.
- */
-
-#include <linux/interrupt.h>
-
-/* XT hard disk controller registers */
-#define XD_DATA		(xd_iobase + 0x00)	/* data RW register */
-#define XD_RESET	(xd_iobase + 0x01)	/* reset WO register */
-#define XD_STATUS	(xd_iobase + 0x01)	/* status RO register */
-#define XD_SELECT	(xd_iobase + 0x02)	/* select WO register */
-#define XD_JUMPER	(xd_iobase + 0x02)	/* jumper RO register */
-#define XD_CONTROL	(xd_iobase + 0x03)	/* DMAE/INTE WO register */
-#define XD_RESERVED	(xd_iobase + 0x03)	/* reserved */
-
-/* XT hard disk controller commands (incomplete list) */
-#define CMD_TESTREADY	0x00	/* test drive ready */
-#define CMD_RECALIBRATE	0x01	/* recalibrate drive */
-#define CMD_SENSE	0x03	/* request sense */
-#define CMD_FORMATDRV	0x04	/* format drive */
-#define CMD_VERIFY	0x05	/* read verify */
-#define CMD_FORMATTRK	0x06	/* format track */
-#define CMD_FORMATBAD	0x07	/* format bad track */
-#define CMD_READ	0x08	/* read */
-#define CMD_WRITE	0x0A	/* write */
-#define CMD_SEEK	0x0B	/* seek */
-
-/* Controller specific commands */
-#define CMD_DTCSETPARAM	0x0C	/* set drive parameters (DTC 5150X & CX only?) */
-#define CMD_DTCGETECC	0x0D	/* get ecc error length (DTC 5150X only?) */
-#define CMD_DTCREADBUF	0x0E	/* read sector buffer (DTC 5150X only?) */
-#define CMD_DTCWRITEBUF 0x0F	/* write sector buffer (DTC 5150X only?) */
-#define CMD_DTCREMAPTRK	0x11	/* assign alternate track (DTC 5150X only?) */
-#define CMD_DTCGETPARAM	0xFB	/* get drive parameters (DTC 5150X only?) */
-#define CMD_DTCSETSTEP	0xFC	/* set step rate (DTC 5150X only?) */
-#define CMD_DTCSETGEOM	0xFE	/* set geometry data (DTC 5150X only?) */
-#define CMD_DTCGETGEOM	0xFF	/* get geometry data (DTC 5150X only?) */
-#define CMD_ST11GETGEOM 0xF8	/* get geometry data (Seagate ST11R/M only?) */
-#define CMD_WDSETPARAM	0x0C	/* set drive parameters (WD 1004A27X only?) */
-#define CMD_XBSETPARAM	0x0C	/* set drive parameters (XEBEC only?) */
-
-/* Bits for command status byte */
-#define CSB_ERROR	0x02	/* error */
-#define CSB_LUN		0x20	/* logical Unit Number */
-
-/* XT hard disk controller status bits */
-#define STAT_READY	0x01	/* controller is ready */
-#define STAT_INPUT	0x02	/* data flowing from controller to host */
-#define STAT_COMMAND	0x04	/* controller in command phase */
-#define STAT_SELECT	0x08	/* controller is selected */
-#define STAT_REQUEST	0x10	/* controller requesting data */
-#define STAT_INTERRUPT	0x20	/* controller requesting interrupt */
-
-/* XT hard disk controller control bits */
-#define PIO_MODE	0x00	/* control bits to set for PIO */
-#define DMA_MODE	0x03	/* control bits to set for DMA & interrupt */
-
-#define XD_MAXDRIVES	2	/* maximum 2 drives */
-#define XD_TIMEOUT	HZ	/* 1 second timeout */
-#define XD_RETRIES	4	/* maximum 4 retries */
-
-#undef DEBUG			/* define for debugging output */
-
-#ifdef DEBUG
-	#define DEBUG_STARTUP	/* debug driver initialisation */
-	#define DEBUG_OVERRIDE	/* debug override geometry detection */
-	#define DEBUG_READWRITE	/* debug each read/write command */
-	#define DEBUG_OTHER	/* debug misc. interrupt/DMA stuff */
-	#define DEBUG_COMMAND	/* debug each controller command */
-#endif /* DEBUG */
-
-/* this structure defines the XT drives and their types */
-typedef struct {
-	u_char heads;
-	u_short cylinders;
-	u_char sectors;
-	u_char control;
-	int unit;
-} XD_INFO;
-
-/* this structure defines a ROM BIOS signature */
-typedef struct {
-	unsigned int offset;
-	const char *string;
-	void (*init_controller)(unsigned int address);
-	void (*init_drive)(u_char drive);
-	const char *name;
-} XD_SIGNATURE;
-
-#ifndef MODULE
-static int xd_manual_geo_init (char *command);
-#endif /* MODULE */
-static u_char xd_detect (u_char *controller, unsigned int *address);
-static u_char xd_initdrives (void (*init_drive)(u_char drive));
-
-static void do_xd_request (struct request_queue * q);
-static int xd_ioctl (struct block_device *bdev,fmode_t mode,unsigned int cmd,unsigned long arg);
-static int xd_readwrite (u_char operation,XD_INFO *disk,char *buffer,u_int block,u_int count);
-static void xd_recalibrate (u_char drive);
-
-static irqreturn_t xd_interrupt_handler(int irq, void *dev_id);
-static u_char xd_setup_dma (u_char opcode,u_char *buffer,u_int count);
-static u_char *xd_build (u_char *cmdblk,u_char command,u_char drive,u_char head,u_short cylinder,u_char sector,u_char count,u_char control);
-static void xd_watchdog (unsigned long unused);
-static inline u_char xd_waitport (u_short port,u_char flags,u_char mask,u_long timeout);
-static u_int xd_command (u_char *command,u_char mode,u_char *indata,u_char *outdata,u_char *sense,u_long timeout);
-
-/* card specific setup and geometry gathering code */
-static void xd_dtc_init_controller (unsigned int address);
-static void xd_dtc5150cx_init_drive (u_char drive);
-static void xd_dtc_init_drive (u_char drive);
-static void xd_wd_init_controller (unsigned int address);
-static void xd_wd_init_drive (u_char drive);
-static void xd_seagate_init_controller (unsigned int address);
-static void xd_seagate_init_drive (u_char drive);
-static void xd_omti_init_controller (unsigned int address);
-static void xd_omti_init_drive (u_char drive);
-static void xd_xebec_init_controller (unsigned int address);
-static void xd_xebec_init_drive (u_char drive);
-static void xd_setparam (u_char command,u_char drive,u_char heads,u_short cylinders,u_short rwrite,u_short wprecomp,u_char ecc);
-static void xd_override_init_drive (u_char drive);
-
-#endif /* _LINUX_XD_H */