Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1626 insertions, 0 deletions

diff --git a/drivers/cdrom/cm206.c b/drivers/cdrom/cm206.c
new file mode 100644
index 00000000000..da80b14335a
--- /dev/null
+++ b/drivers/cdrom/cm206.c
@@ -0,0 +1,1626 @@
+/* cm206.c. A linux-driver for the cm206 cdrom player with cm260 adapter card.
+   Copyright (c) 1995--1997 David A. van Leeuwen.
+   $Id: cm206.c,v 1.5 1997/12/26 11:02:51 david Exp $
+   
+     This program is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published by
+     the Free Software Foundation; either version 2 of the License, or
+     (at your option) any later version.
+     
+     This program is distributed in the hope that it will be useful,
+     but WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+     GNU General Public License for more details.
+     
+     You should have received a copy of the GNU General Public License
+     along with this program; if not, write to the Free Software
+     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+History:
+ Started 25 jan 1994. Waiting for documentation...
+ 22 feb 1995: 0.1a first reasonably safe polling driver.
+	      Two major bugs, one in read_sector and one in 
+	      do_cm206_request, happened to cancel!
+ 25 feb 1995: 0.2a first reasonable interrupt driven version of above.
+              uart writes are still done in polling mode. 
+ 25 feb 1995: 0.21a writes also in interrupt mode, still some
+	      small bugs to be found... Larger buffer. 
+  2 mrt 1995: 0.22 Bug found (cd-> nowhere, interrupt was called in
+              initialization), read_ahead of 16. Timeouts implemented.
+	      unclear if they do something...
+  7 mrt 1995: 0.23 Start of background read-ahead.
+ 18 mrt 1995: 0.24 Working background read-ahead. (still problems)
+ 26 mrt 1995: 0.25 Multi-session ioctl added (kernel v1.2).
+              Statistics implemented, though separate stats206.h.
+	      Accessible trough ioctl 0x1000 (just a number).
+	      Hard to choose between v1.2 development and 1.1.75.
+	      Bottom-half doesn't work with 1.2...
+	      0.25a: fixed... typo. Still problems...
+  1 apr 1995: 0.26 Module support added. Most bugs found. Use kernel 1.2.n.
+  5 apr 1995: 0.27 Auto-probe for the adapter card base address.
+              Auto-probe for the adaptor card irq line.
+  7 apr 1995: 0.28 Added lilo setup support for base address and irq.
+              Use major number 32 (not in this source), officially
+	      assigned to this driver.
+  9 apr 1995: 0.29 Added very limited audio support. Toc_header, stop, pause,
+              resume, eject. Play_track ignores track info, because we can't 
+	      read a table-of-contents entry. Toc_entry is implemented
+	      as a `placebo' function: always returns start of disc. 
+  3 may 1995: 0.30 Audio support completed. The get_toc_entry function
+              is implemented as a binary search. 
+ 15 may 1995: 0.31 More work on audio stuff. Workman is not easy to 
+              satisfy; changed binary search into linear search.
+	      Auto-probe for base address somewhat relaxed.
+  1 jun 1995: 0.32 Removed probe_irq_on/off for module version.
+ 10 jun 1995: 0.33 Workman still behaves funny, but you should be
+              able to eject and substitute another disc.
+
+ An adaptation of 0.33 is included in linux-1.3.7 by Eberhard Moenkeberg
+
+ 18 jul 1995: 0.34 Patch by Heiko Eissfeldt included, mainly considering 
+              verify_area's in the ioctls. Some bugs introduced by 
+	      EM considering the base port and irq fixed. 
+
+ 18 dec 1995: 0.35 Add some code for error checking... no luck...
+
+ We jump to reach our goal: version 1.0 in the next stable linux kernel.
+
+ 19 mar 1996: 0.95 Different implementation of CDROM_GET_UPC, on
+	      request of Thomas Quinot. 
+ 25 mar 1996: 0.96 Interpretation of opening with O_WRONLY or O_RDWR:
+	      open only for ioctl operation, e.g., for operation of
+	      tray etc.
+ 4 apr 1996:  0.97 First implementation of layer between VFS and cdrom
+              driver, a generic interface. Much of the functionality
+	      of cm206_open() and cm206_ioctl() is transferred to a
+	      new file cdrom.c and its header ucdrom.h. 
+
+	      Upgrade to Linux kernel 1.3.78. 
+
+ 11 apr 1996  0.98 Upgrade to Linux kernel 1.3.85
+              More code moved to cdrom.c
+ 
+ 	      0.99 Some more small changes to decrease number
+ 	      of oopses at module load; 
+ 
+ 27 jul 1996  0.100 Many hours of debugging, kernel change from 1.2.13
+	      to 2.0.7 seems to have introduced some weird behavior
+	      in (interruptible_)sleep_on(&cd->data): the process
+	      seems to be woken without any explicit wake_up in my own
+	      code. Patch to try 100x in case such untriggered wake_up's 
+	      occur. 
+
+ 28 jul 1996  0.101 Rewriting of the code that receives the command echo,
+	      using a fifo to store echoed bytes. 
+
+ 	      Branch from 0.99:
+ 
+ 	      0.99.1.0 Update to kernel release 2.0.10 dev_t -> kdev_t
+ 	      (emoenke) various typos found by others.  extra
+ 	      module-load oops protection.
+ 
+ 	      0.99.1.1 Initialization constant cdrom_dops.speed
+ 	      changed from float (2.0) to int (2); Cli()-sti() pair
+ 	      around cm260_reset() in module initialization code.
+ 
+ 	      0.99.1.2 Changes literally as proposed by Scott Snyder
+ 	      <snyder@d0sgif.fnal.gov> for the 2.1 kernel line, which
+ 	      have to do mainly with the poor minor support i had. The
+ 	      major new concept is to change a cdrom driver's
+ 	      operations struct from the capabilities struct. This
+ 	      reflects the fact that there is one major for a driver,
+ 	      whilst there can be many minors whith completely
+ 	      different capabilities.
+
+	      0.99.1.3 More changes for operations/info separation.
+
+	      0.99.1.4 Added speed selection (someone had to do this
+	      first).
+
+  23 jan 1997 0.99.1.5 MODULE_PARMS call added.
+
+  23 jan 1997 0.100.1.2--0.100.1.5 following similar lines as 
+  	      0.99.1.1--0.99.1.5. I get too many complaints about the
+	      drive making read errors. What't wrong with the 2.0+
+	      kernel line? Why get i (and othe cm206 owners) weird
+	      results? Why were things good in the good old 1.1--1.2 
+	      era? Why don't i throw away the drive?
+
+ 2 feb 1997   0.102 Added `volatile' to values in cm206_struct. Seems to 
+ 	      reduce many of the problems. Rewrote polling routines
+	      to use fixed delays between polls. 
+	      0.103 Changed printk behavior. 
+	      0.104 Added a 0.100 -> 0.100.1.1 change
+
+11 feb 1997   0.105 Allow auto_probe during module load, disable
+              with module option "auto_probe=0". Moved some debugging
+	      statements to lower priority. Implemented select_speed()
+	      function. 
+
+13 feb 1997   1.0 Final version for 2.0 kernel line. 
+
+	      All following changes will be for the 2.1 kernel line. 
+
+15 feb 1997   1.1 Keep up with kernel 2.1.26, merge in changes from 
+              cdrom.c 0.100.1.1--1.0. Add some more MODULE_PARMS. 
+
+14 sep 1997   1.2 Upgrade to Linux 2.1.55.  Added blksize_size[], patch
+              sent by James Bottomley <James.Bottomley@columbiasc.ncr.com>.
+
+21 dec 1997   1.4 Upgrade to Linux 2.1.72.  
+
+24 jan 1998   Removed the cm206_disc_status() function, as it was now dead
+              code.  The Uniform CDROM driver now provides this functionality.
+	      
+9 Nov. 1999   Make kernel-parameter implementation work with 2.3.x 
+	      Removed init_module & cleanup_module in favor of 
+	      module_init & module_exit.
+	      Torben Mathiasen <tmm@image.dk>
+ * 
+ * Parts of the code are based upon lmscd.c written by Kai Petzke,
+ * sbpcd.c written by Eberhard Moenkeberg, and mcd.c by Martin
+ * Harriss, but any off-the-shelf dynamic programming algorithm won't
+ * be able to find them.
+ *
+ * The cm206 drive interface and the cm260 adapter card seem to be 
+ * sufficiently different from their cm205/cm250 counterparts
+ * in order to write a complete new driver.
+ * 
+ * I call all routines connected to the Linux kernel something
+ * with `cm206' in it, as this stuff is too series-dependent. 
+ * 
+ * Currently, my limited knowledge is based on:
+ * - The Linux Kernel Hacker's guide, v. 0.5, by Michael K. Johnson
+ * - Linux Kernel Programmierung, by Michael Beck and others
+ * - Philips/LMS cm206 and cm226 product specification
+ * - Philips/LMS cm260 product specification
+ *
+ * David van Leeuwen, david@tm.tno.nl.  */
+#define REVISION "$Revision: 1.5 $"
+
+#include <linux/module.h>
+
+#include <linux/errno.h>	/* These include what we really need */
+#include <linux/delay.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/timer.h>
+#include <linux/cdrom.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/ioport.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+
+/* #include <linux/ucdrom.h> */
+
+#include <asm/io.h>
+
+#define MAJOR_NR CM206_CDROM_MAJOR
+
+#include <linux/blkdev.h>
+
+#undef DEBUG
+#define STATISTICS		/* record times and frequencies of events */
+#define AUTO_PROBE_MODULE
+#define USE_INSW
+
+#include "cm206.h"
+
+/* This variable defines whether or not to probe for adapter base port 
+   address and interrupt request. It can be overridden by the boot 
+   parameter `auto'.
+*/
+static int auto_probe = 1;	/* Yes, why not? */
+
+static int cm206_base = CM206_BASE;
+static int cm206_irq = CM206_IRQ;
+#ifdef MODULE
+static int cm206[2] = { 0, 0 };	/* for compatible `insmod' parameter passing */
+#endif
+
+MODULE_PARM(cm206_base, "i");	/* base */
+MODULE_PARM(cm206_irq, "i");	/* irq */
+MODULE_PARM(cm206, "1-2i");	/* base,irq or irq,base */
+MODULE_PARM(auto_probe, "i");	/* auto probe base and irq */
+MODULE_LICENSE("GPL");
+
+#define POLLOOP 100		/* milliseconds */
+#define READ_AHEAD 1		/* defines private buffer, waste! */
+#define BACK_AHEAD 1		/* defines adapter-read ahead */
+#define DATA_TIMEOUT (3*HZ)	/* measured in jiffies (10 ms) */
+#define UART_TIMEOUT (5*HZ/100)
+#define DSB_TIMEOUT (7*HZ)	/* time for the slowest command to finish */
+#define UR_SIZE 4		/* uart receive buffer fifo size */
+
+#define LINUX_BLOCK_SIZE 512	/* WHERE is this defined? */
+#define RAW_SECTOR_SIZE 2352	/* ok, is also defined in cdrom.h */
+#define ISO_SECTOR_SIZE 2048
+#define BLOCKS_ISO (ISO_SECTOR_SIZE/LINUX_BLOCK_SIZE)	/* 4 */
+#define CD_SYNC_HEAD 16		/* CD_SYNC + CD_HEAD */
+
+#ifdef STATISTICS		/* keep track of errors in counters */
+#define stats(i) { ++cd->stats[st_ ## i]; \
+		     cd->last_stat[st_ ## i] = cd->stat_counter++; \
+		 }
+#else
+#define stats(i) (void) 0;
+#endif
+
+#define Debug(a) {printk (KERN_DEBUG); printk a;}
+#ifdef DEBUG
+#define debug(a) Debug(a)
+#else
+#define debug(a) (void) 0;
+#endif
+
+typedef unsigned char uch;	/* 8-bits */
+typedef unsigned short ush;	/* 16-bits */
+
+struct toc_struct {		/* private copy of Table of Contents */
+	uch track, fsm[3], q0;
+};
+
+struct cm206_struct {
+	volatile ush intr_ds;	/* data status read on last interrupt */
+	volatile ush intr_ls;	/* uart line status read on last interrupt */
+	volatile uch ur[UR_SIZE];	/* uart receive buffer fifo */
+	volatile uch ur_w, ur_r;	/* write/read buffer index */
+	volatile uch dsb, cc;	/* drive status byte and condition (error) code */
+	int command;		/* command to be written to the uart */
+	int openfiles;
+	ush sector[READ_AHEAD * RAW_SECTOR_SIZE / 2];	/* buffered cd-sector */
+	int sector_first, sector_last;	/* range of these sectors */
+	wait_queue_head_t uart;	/* wait queues for interrupt */
+	wait_queue_head_t data;
+	struct timer_list timer;	/* time-out */
+	char timed_out;
+	signed char max_sectors;	/* number of sectors that fit in adapter mem */
+	char wait_back;		/* we're waiting for a background-read */
+	char background;	/* is a read going on in the background? */
+	int adapter_first;	/* if so, that's the starting sector */
+	int adapter_last;
+	char fifo_overflowed;
+	uch disc_status[7];	/* result of get_disc_status command */
+#ifdef STATISTICS
+	int stats[NR_STATS];
+	int last_stat[NR_STATS];	/* `time' at which stat was stat */
+	int stat_counter;
+#endif
+	struct toc_struct toc[101];	/* The whole table of contents + lead-out */
+	uch q[10];		/* Last read q-channel info */
+	uch audio_status[5];	/* last read position on pause */
+	uch media_changed;	/* record if media changed */
+};
+
+#define DISC_STATUS cd->disc_status[0]
+#define FIRST_TRACK cd->disc_status[1]
+#define LAST_TRACK cd->disc_status[2]
+#define PAUSED cd->audio_status[0]	/* misuse this memory byte! */
+#define PLAY_TO cd->toc[0]	/* toc[0] records end-time in play */
+
+static struct cm206_struct *cd;	/* the main memory structure */
+static struct request_queue *cm206_queue;
+static DEFINE_SPINLOCK(cm206_lock);
+
+/* First, we define some polling functions. These are actually
+   only being used in the initialization. */
+
+void send_command_polled(int command)
+{
+	int loop = POLLOOP;
+	while (!(inw(r_line_status) & ls_transmitter_buffer_empty)
+	       && loop > 0) {
+		mdelay(1);	/* one millisec delay */
+		--loop;
+	}
+	outw(command, r_uart_transmit);
+}
+
+uch receive_echo_polled(void)
+{
+	int loop = POLLOOP;
+	while (!(inw(r_line_status) & ls_receive_buffer_full) && loop > 0) {
+		mdelay(1);
+		--loop;
+	}
+	return ((uch) inw(r_uart_receive));
+}
+
+uch send_receive_polled(int command)
+{
+	send_command_polled(command);
+	return receive_echo_polled();
+}
+
+inline void clear_ur(void)
+{
+	if (cd->ur_r != cd->ur_w) {
+		debug(("Deleting bytes from fifo:"));
+		for (; cd->ur_r != cd->ur_w;
+		     cd->ur_r++, cd->ur_r %= UR_SIZE)
+			debug((" 0x%x", cd->ur[cd->ur_r]));
+		debug(("\n"));
+	}
+}
+
+static struct tasklet_struct cm206_tasklet;
+
+/* The interrupt handler. When the cm260 generates an interrupt, very
+   much care has to be taken in reading out the registers in the right
+   order; in case of a receive_buffer_full interrupt, first the
+   uart_receive must be read, and then the line status again to
+   de-assert the interrupt line. It took me a couple of hours to find
+   this out:-( 
+
+   The function reset_cm206 appears to cause an interrupt, because
+   pulling up the INIT line clears both the uart-write-buffer /and/
+   the uart-write-buffer-empty mask. We call this a `lost interrupt,'
+   as there seems so reason for this to happen.
+*/
+
+static irqreturn_t cm206_interrupt(int sig, void *dev_id, struct pt_regs *regs)
+{
+	volatile ush fool;
+	cd->intr_ds = inw(r_data_status);	/* resets data_ready, data_error,
+						   crc_error, sync_error, toc_ready 
+						   interrupts */
+	cd->intr_ls = inw(r_line_status);	/* resets overrun bit */
+	debug(("Intr, 0x%x 0x%x, %d\n", cd->intr_ds, cd->intr_ls,
+	       cd->background));
+	if (cd->intr_ls & ls_attention)
+		stats(attention);
+	/* receive buffer full? */
+	if (cd->intr_ls & ls_receive_buffer_full) {
+		cd->ur[cd->ur_w] = inb(r_uart_receive);	/* get order right! */
+		cd->intr_ls = inw(r_line_status);	/* resets rbf interrupt */
+		debug(("receiving #%d: 0x%x\n", cd->ur_w,
+		       cd->ur[cd->ur_w]));
+		cd->ur_w++;
+		cd->ur_w %= UR_SIZE;
+		if (cd->ur_w == cd->ur_r)
+			debug(("cd->ur overflow!\n"));
+		if (waitqueue_active(&cd->uart) && cd->background < 2) {
+			del_timer(&cd->timer);
+			wake_up_interruptible(&cd->uart);
+		}
+	}
+	/* data ready in fifo? */
+	else if (cd->intr_ds & ds_data_ready) {
+		if (cd->background)
+			++cd->adapter_last;
+		if (waitqueue_active(&cd->data)
+		    && (cd->wait_back || !cd->background)) {
+			del_timer(&cd->timer);
+			wake_up_interruptible(&cd->data);
+		}
+		stats(data_ready);
+	}
+	/* ready to issue a write command? */
+	else if (cd->command && cd->intr_ls & ls_transmitter_buffer_empty) {
+		outw(dc_normal | (inw(r_data_status) & 0x7f),
+		     r_data_control);
+		outw(cd->command, r_uart_transmit);
+		cd->command = 0;
+		if (!cd->background)
+			wake_up_interruptible(&cd->uart);
+	}
+	/* now treat errors (at least, identify them for debugging) */
+	else if (cd->intr_ds & ds_fifo_overflow) {
+		debug(("Fifo overflow at sectors 0x%x\n",
+		       cd->sector_first));
+		fool = inw(r_fifo_output_buffer);	/* de-assert the interrupt */
+		cd->fifo_overflowed = 1;	/* signal one word less should be read */
+		stats(fifo_overflow);
+	} else if (cd->intr_ds & ds_data_error) {
+		debug(("Data error at sector 0x%x\n", cd->sector_first));
+		stats(data_error);
+	} else if (cd->intr_ds & ds_crc_error) {
+		debug(("CRC error at sector 0x%x\n", cd->sector_first));
+		stats(crc_error);
+	} else if (cd->intr_ds & ds_sync_error) {
+		debug(("Sync at sector 0x%x\n", cd->sector_first));
+		stats(sync_error);
+	} else if (cd->intr_ds & ds_toc_ready) {
+		/* do something appropriate */
+	}
+	/* couldn't see why this interrupt, maybe due to init */
+	else {
+		outw(dc_normal | READ_AHEAD, r_data_control);
+		stats(lost_intr);
+	}
+	if (cd->background
+	    && (cd->adapter_last - cd->adapter_first == cd->max_sectors
+		|| cd->fifo_overflowed))
+		tasklet_schedule(&cm206_tasklet);	/* issue a stop read command */
+	stats(interrupt);
+	return IRQ_HANDLED;
+}
+
+/* we have put the address of the wait queue in who */
+void cm206_timeout(unsigned long who)
+{
+	cd->timed_out = 1;
+	debug(("Timing out\n"));
+	wake_up_interruptible((wait_queue_head_t *) who);
+}
+
+/* This function returns 1 if a timeout occurred, 0 if an interrupt
+   happened */
+int sleep_or_timeout(wait_queue_head_t * wait, int timeout)
+{
+	cd->timed_out = 0;
+	init_timer(&cd->timer);
+	cd->timer.data = (unsigned long) wait;
+	cd->timer.expires = jiffies + timeout;
+	add_timer(&cd->timer);
+	debug(("going to sleep\n"));
+	interruptible_sleep_on(wait);
+	del_timer(&cd->timer);
+	if (cd->timed_out) {
+		cd->timed_out = 0;
+		return 1;
+	} else
+		return 0;
+}
+
+void cm206_delay(int nr_jiffies)
+{
+	DECLARE_WAIT_QUEUE_HEAD(wait);
+	sleep_or_timeout(&wait, nr_jiffies);
+}
+
+void send_command(int command)
+{
+	debug(("Sending 0x%x\n", command));
+	if (!(inw(r_line_status) & ls_transmitter_buffer_empty)) {
+		cd->command = command;
+		cli();		/* don't interrupt before sleep */
+		outw(dc_mask_sync_error | dc_no_stop_on_error |
+		     (inw(r_data_status) & 0x7f), r_data_control);
+		/* interrupt routine sends command */
+		if (sleep_or_timeout(&cd->uart, UART_TIMEOUT)) {
+			debug(("Time out on write-buffer\n"));
+			stats(write_timeout);
+			outw(command, r_uart_transmit);
+		}
+		debug(("Write commmand delayed\n"));
+	} else
+		outw(command, r_uart_transmit);
+}
+
+uch receive_byte(int timeout)
+{
+	uch ret;
+	cli();
+	debug(("cli\n"));
+	ret = cd->ur[cd->ur_r];
+	if (cd->ur_r != cd->ur_w) {
+		sti();
+		debug(("returning #%d: 0x%x\n", cd->ur_r,
+		       cd->ur[cd->ur_r]));
+		cd->ur_r++;
+		cd->ur_r %= UR_SIZE;
+		return ret;
+	} else if (sleep_or_timeout(&cd->uart, timeout)) {	/* does sti() */
+		debug(("Time out on receive-buffer\n"));
+#ifdef STATISTICS
+		if (timeout == UART_TIMEOUT)
+			stats(receive_timeout)	/* no `;'! */
+			    else
+			stats(dsb_timeout);
+#endif
+		return 0xda;
+	}
+	ret = cd->ur[cd->ur_r];
+	debug(("slept; returning #%d: 0x%x\n", cd->ur_r,
+	       cd->ur[cd->ur_r]));
+	cd->ur_r++;
+	cd->ur_r %= UR_SIZE;
+	return ret;
+}
+
+inline uch receive_echo(void)
+{
+	return receive_byte(UART_TIMEOUT);
+}
+
+inline uch send_receive(int command)
+{
+	send_command(command);
+	return receive_echo();
+}
+
+inline uch wait_dsb(void)
+{
+	return receive_byte(DSB_TIMEOUT);
+}
+
+int type_0_command(int command, int expect_dsb)
+{
+	int e;
+	clear_ur();
+	if (command != (e = send_receive(command))) {
+		debug(("command 0x%x echoed as 0x%x\n", command, e));
+		stats(echo);
+		return -1;
+	}
+	if (expect_dsb) {
+		cd->dsb = wait_dsb();	/* wait for command to finish */
+	}
+	return 0;
+}
+
+int type_1_command(int command, int bytes, uch * status)
+{				/* returns info */
+	int i;
+	if (type_0_command(command, 0))
+		return -1;
+	for (i = 0; i < bytes; i++)
+		status[i] = send_receive(c_gimme);
+	return 0;
+}
+
+/* This function resets the adapter card. We'd better not do this too
+ * often, because it tends to generate `lost interrupts.' */
+void reset_cm260(void)
+{
+	outw(dc_normal | dc_initialize | READ_AHEAD, r_data_control);
+	udelay(10);		/* 3.3 mu sec minimum */
+	outw(dc_normal | READ_AHEAD, r_data_control);
+}
+
+/* fsm: frame-sec-min from linear address; one of many */
+void fsm(int lba, uch * fsm)
+{
+	fsm[0] = lba % 75;
+	lba /= 75;
+	lba += 2;
+	fsm[1] = lba % 60;
+	fsm[2] = lba / 60;
+}
+
+inline int fsm2lba(uch * fsm)
+{
+	return fsm[0] + 75 * (fsm[1] - 2 + 60 * fsm[2]);
+}
+
+inline int f_s_m2lba(uch f, uch s, uch m)
+{
+	return f + 75 * (s - 2 + 60 * m);
+}
+
+int start_read(int start)
+{
+	uch read_sector[4] = { c_read_data, };
+	int i, e;
+
+	fsm(start, &read_sector[1]);
+	clear_ur();
+	for (i = 0; i < 4; i++)
+		if (read_sector[i] != (e = send_receive(read_sector[i]))) {
+			debug(("read_sector: %x echoes %x\n",
+			       read_sector[i], e));
+			stats(echo);
+			if (e == 0xff) {	/* this seems to happen often */
+				e = receive_echo();
+				debug(("Second try %x\n", e));
+				if (e != read_sector[i])
+					return -1;
+			}
+		}
+	return 0;
+}
+
+int stop_read(void)
+{
+	int e;
+	type_0_command(c_stop, 0);
+	if ((e = receive_echo()) != 0xff) {
+		debug(("c_stop didn't send 0xff, but 0x%x\n", e));
+		stats(stop_0xff);
+		return -1;
+	}
+	return 0;
+}
+
+/* This function starts to read sectors in adapter memory, the
+   interrupt routine should stop the read. In fact, the bottom_half
+   routine takes care of this. Set a flag `background' in the cd
+   struct to indicate the process. */
+
+int read_background(int start, int reading)
+{
+	if (cd->background)
+		return -1;	/* can't do twice */
+	outw(dc_normal | BACK_AHEAD, r_data_control);
+	if (!reading && start_read(start))
+		return -2;
+	cd->adapter_first = cd->adapter_last = start;
+	cd->background = 1;	/* flag a read is going on */
+	return 0;
+}
+
+#ifdef USE_INSW
+#define transport_data insw
+#else
+/* this routine implements insw(,,). There was a time i had the
+   impression that there would be any difference in error-behaviour. */
+void transport_data(int port, ush * dest, int count)
+{
+	int i;
+	ush *d;
+	for (i = 0, d = dest; i < count; i++, d++)
+		*d = inw(port);
+}
+#endif
+
+
+#define MAX_TRIES 100
+int read_sector(int start)
+{
+	int tries = 0;
+	if (cd->background) {
+		cd->background = 0;
+		cd->adapter_last = -1;	/* invalidate adapter memory */
+		stop_read();
+	}
+	cd->fifo_overflowed = 0;
+	reset_cm260();		/* empty fifo etc. */
+	if (start_read(start))
+		return -1;
+	do {
+		if (sleep_or_timeout(&cd->data, DATA_TIMEOUT)) {
+			debug(("Read timed out sector 0x%x\n", start));
+			stats(read_timeout);
+			stop_read();
+			return -3;
+		}
+		tries++;
+	} while (cd->intr_ds & ds_fifo_empty && tries < MAX_TRIES);
+	if (tries > 1)
+		debug(("Took me some tries\n"))
+		    else
+	if (tries == MAX_TRIES)
+		debug(("MAX_TRIES tries for read sector\n"));
+	transport_data(r_fifo_output_buffer, cd->sector,
+		       READ_AHEAD * RAW_SECTOR_SIZE / 2);
+	if (read_background(start + READ_AHEAD, 1))
+		stats(read_background);
+	cd->sector_first = start;
+	cd->sector_last = start + READ_AHEAD;
+	stats(read_restarted);
+	return 0;
+}
+
+/* The function of bottom-half is to send a stop command to the drive
+   This isn't easy because the routine is not `owned' by any process;
+   we can't go to sleep! The variable cd->background gives the status:
+   0 no read pending
+   1 a read is pending
+   2 c_stop waits for write_buffer_empty
+   3 c_stop waits for receive_buffer_full: echo
+   4 c_stop waits for receive_buffer_full: 0xff
+*/
+
+static void cm206_tasklet_func(unsigned long ignore)
+{
+	debug(("bh: %d\n", cd->background));
+	switch (cd->background) {
+	case 1:
+		stats(bh);
+		if (!(cd->intr_ls & ls_transmitter_buffer_empty)) {
+			cd->command = c_stop;
+			outw(dc_mask_sync_error | dc_no_stop_on_error |
+			     (inw(r_data_status) & 0x7f), r_data_control);
+			cd->background = 2;
+			break;	/* we'd better not time-out here! */
+		} else
+			outw(c_stop, r_uart_transmit);
+		/* fall into case 2: */
+	case 2:
+		/* the write has been satisfied by interrupt routine */
+		cd->background = 3;
+		break;
+	case 3:
+		if (cd->ur_r != cd->ur_w) {
+			if (cd->ur[cd->ur_r] != c_stop) {
+				debug(("cm206_bh: c_stop echoed 0x%x\n",
+				       cd->ur[cd->ur_r]));
+				stats(echo);
+			}
+			cd->ur_r++;
+			cd->ur_r %= UR_SIZE;
+		}
+		cd->background++;
+		break;
+	case 4:
+		if (cd->ur_r != cd->ur_w) {
+			if (cd->ur[cd->ur_r] != 0xff) {
+				debug(("cm206_bh: c_stop reacted with 0x%x\n", cd->ur[cd->ur_r]));
+				stats(stop_0xff);
+			}
+			cd->ur_r++;
+			cd->ur_r %= UR_SIZE;
+		}
+		cd->background = 0;
+	}
+}
+
+static DECLARE_TASKLET(cm206_tasklet, cm206_tasklet_func, 0);
+
+/* This command clears the dsb_possible_media_change flag, so we must 
+ * retain it.
+ */
+void get_drive_status(void)
+{
+	uch status[2];
+	type_1_command(c_drive_status, 2, status);	/* this might be done faster */
+	cd->dsb = status[0];
+	cd->cc = status[1];
+	cd->media_changed |=
+	    !!(cd->dsb & (dsb_possible_media_change |
+			  dsb_drive_not_ready | dsb_tray_not_closed));
+}
+
+void get_disc_status(void)
+{
+	if (type_1_command(c_disc_status, 7, cd->disc_status)) {
+		debug(("get_disc_status: error\n"));
+	}
+}
+
+/* The new open. The real opening strategy is defined in cdrom.c. */
+
+static int cm206_open(struct cdrom_device_info *cdi, int purpose)
+{
+	if (!cd->openfiles) {	/* reset only first time */
+		cd->background = 0;
+		reset_cm260();
+		cd->adapter_last = -1;	/* invalidate adapter memory */
+		cd->sector_last = -1;
+	}
+	++cd->openfiles;
+	stats(open);
+	return 0;
+}
+
+static void cm206_release(struct cdrom_device_info *cdi)
+{
+	if (cd->openfiles == 1) {
+		if (cd->background) {
+			cd->background = 0;
+			stop_read();
+		}
+		cd->sector_last = -1;	/* Make our internal buffer invalid */
+		FIRST_TRACK = 0;	/* No valid disc status */
+	}
+	--cd->openfiles;
+}
+
+/* Empty buffer empties $sectors$ sectors of the adapter card buffer,
+ * and then reads a sector in kernel memory.  */
+void empty_buffer(int sectors)
+{
+	while (sectors >= 0) {
+		transport_data(r_fifo_output_buffer,
+			       cd->sector + cd->fifo_overflowed,
+			       RAW_SECTOR_SIZE / 2 - cd->fifo_overflowed);
+		--sectors;
+		++cd->adapter_first;	/* update the current adapter sector */
+		cd->fifo_overflowed = 0;	/* reset overflow bit */
+		stats(sector_transferred);
+	}
+	cd->sector_first = cd->adapter_first - 1;
+	cd->sector_last = cd->adapter_first;	/* update the buffer sector */
+}
+
+/* try_adapter. This function determines if the requested sector is
+   in adapter memory, or will appear there soon. Returns 0 upon
+   success */
+int try_adapter(int sector)
+{
+	if (cd->adapter_first <= sector && sector < cd->adapter_last) {
+		/* sector is in adapter memory */
+		empty_buffer(sector - cd->adapter_first);
+		return 0;
+	} else if (cd->background == 1 && cd->adapter_first <= sector
+		   && sector < cd->adapter_first + cd->max_sectors) {
+		/* a read is going on, we can wait for it */
+		cd->wait_back = 1;
+		while (sector >= cd->adapter_last) {
+			if (sleep_or_timeout(&cd->data, DATA_TIMEOUT)) {
+				debug(("Timed out during background wait: %d %d %d %d\n", sector, cd->adapter_last, cd->adapter_first, cd->background));
+				stats(back_read_timeout);
+				cd->wait_back = 0;
+				return -1;
+			}
+		}
+		cd->wait_back = 0;
+		empty_buffer(sector - cd->adapter_first);
+		return 0;
+	} else
+		return -2;
+}
+
+/* This is not a very smart implementation. We could optimize for 
+   consecutive block numbers. I'm not convinced this would really
+   bring down the processor load. */
+static void do_cm206_request(request_queue_t * q)
+{
+	long int i, cd_sec_no;
+	int quarter, error;
+	uch *source, *dest;
+	struct request *req;
+
+	while (1) {	/* repeat until all requests have been satisfied */
+		req = elv_next_request(q);
+		if (!req)
+			return;
+
+		if (req->cmd != READ) {
+			debug(("Non-read command %d on cdrom\n", req->cmd));
+			end_request(req, 0);
+			continue;
+		}
+		spin_unlock_irq(q->queue_lock);
+		error = 0;
+		for (i = 0; i < req->nr_sectors; i++) {
+			int e1, e2;
+			cd_sec_no = (req->sector + i) / BLOCKS_ISO;	/* 4 times 512 bytes */
+			quarter = (req->sector + i) % BLOCKS_ISO;
+			dest = req->buffer + i * LINUX_BLOCK_SIZE;
+			/* is already in buffer memory? */
+			if (cd->sector_first <= cd_sec_no
+			    && cd_sec_no < cd->sector_last) {
+				source =
+				    ((uch *) cd->sector) + 16 +
+				    quarter * LINUX_BLOCK_SIZE +
+				    (cd_sec_no -
+				     cd->sector_first) * RAW_SECTOR_SIZE;
+				memcpy(dest, source, LINUX_BLOCK_SIZE);
+			} else if (!(e1 = try_adapter(cd_sec_no)) ||
+				   !(e2 = read_sector(cd_sec_no))) {
+				source =
+				    ((uch *) cd->sector) + 16 +
+				    quarter * LINUX_BLOCK_SIZE;
+				memcpy(dest, source, LINUX_BLOCK_SIZE);
+			} else {
+				error = 1;
+				debug(("cm206_request: %d %d\n", e1, e2));
+			}
+		}
+		spin_lock_irq(q->queue_lock);
+		end_request(req, !error);
+	}
+}
+
+/* Audio support. I've tried very hard, but the cm206 drive doesn't 
+   seem to have a get_toc (table-of-contents) function, while i'm
+   pretty sure it must read the toc upon disc insertion. Therefore
+   this function has been implemented through a binary search 
+   strategy. All track starts that happen to be found are stored in
+   cd->toc[], for future use. 
+
+   I've spent a whole day on a bug that only shows under Workman---
+   I don't get it. Tried everything, nothing works. If workman asks
+   for track# 0xaa, it'll get the wrong time back. Any other program
+   receives the correct value. I'm stymied.
+*/
+
+/* seek seeks to address lba. It does wait to arrive there. */
+void seek(int lba)
+{
+	int i;
+	uch seek_command[4] = { c_seek, };
+
+	fsm(lba, &seek_command[1]);
+	for (i = 0; i < 4; i++)
+		type_0_command(seek_command[i], 0);
+	cd->dsb = wait_dsb();
+}
+
+uch bcdbin(unsigned char bcd)
+{				/* stolen from mcd.c! */
+	return (bcd >> 4) * 10 + (bcd & 0xf);
+}
+
+inline uch normalize_track(uch track)
+{
+	if (track < 1)
+		return 1;
+	if (track > LAST_TRACK)
+		return LAST_TRACK + 1;
+	return track;
+}
+
+/* This function does a binary search for track start. It records all
+ * tracks seen in the process. Input $track$ must be between 1 and
+ * #-of-tracks+1.  Note that the start of the disc must be in toc[1].fsm. 
+ */
+int get_toc_lba(uch track)
+{
+	int max = 74 * 60 * 75 - 150, min = fsm2lba(cd->toc[1].fsm);
+	int i, lba, l, old_lba = 0;
+	uch *q = cd->q;
+	uch ct;			/* current track */
+	int binary = 0;
+	const int skip = 3 * 60 * 75;	/* 3 minutes */
+
+	for (i = track; i > 0; i--)
+		if (cd->toc[i].track) {
+			min = fsm2lba(cd->toc[i].fsm);
+			break;
+		}
+	lba = min + skip;
+	do {
+		seek(lba);
+		type_1_command(c_read_current_q, 10, q);
+		ct = normalize_track(q[1]);
+		if (!cd->toc[ct].track) {
+			l = q[9] - bcdbin(q[5]) + 75 * (q[8] -
+							bcdbin(q[4]) - 2 +
+							60 * (q[7] -
+							      bcdbin(q
+								     [3])));
+			cd->toc[ct].track = q[1];	/* lead out still 0xaa */
+			fsm(l, cd->toc[ct].fsm);
+			cd->toc[ct].q0 = q[0];	/* contains adr and ctrl info */
+			if (ct == track)
+				return l;
+		}
+		old_lba = lba;
+		if (binary) {
+			if (ct < track)
+				min = lba;
+			else
+				max = lba;
+			lba = (min + max) / 2;
+		} else {
+			if (ct < track)
+				lba += skip;
+			else {
+				binary = 1;
+				max = lba;
+				min = lba - skip;
+				lba = (min + max) / 2;
+			}
+		}
+	} while (lba != old_lba);
+	return lba;
+}
+
+void update_toc_entry(uch track)
+{
+	track = normalize_track(track);
+	if (!cd->toc[track].track)
+		get_toc_lba(track);
+}
+
+/* return 0 upon success */
+int read_toc_header(struct cdrom_tochdr *hp)
+{
+	if (!FIRST_TRACK)
+		get_disc_status();
+	if (hp) {
+		int i;
+		hp->cdth_trk0 = FIRST_TRACK;
+		hp->cdth_trk1 = LAST_TRACK;
+		/* fill in first track position */
+		for (i = 0; i < 3; i++)
+			cd->toc[1].fsm[i] = cd->disc_status[3 + i];
+		update_toc_entry(LAST_TRACK + 1);	/* find most entries */
+		return 0;
+	}
+	return -1;
+}
+
+void play_from_to_msf(struct cdrom_msf *msfp)
+{
+	uch play_command[] = { c_play,
+		msfp->cdmsf_frame0, msfp->cdmsf_sec0, msfp->cdmsf_min0,
+		msfp->cdmsf_frame1, msfp->cdmsf_sec1, msfp->cdmsf_min1, 2,
+		    2
+	};
+	int i;
+	for (i = 0; i < 9; i++)
+		type_0_command(play_command[i], 0);
+	for (i = 0; i < 3; i++)
+		PLAY_TO.fsm[i] = play_command[i + 4];
+	PLAY_TO.track = 0;	/* say no track end */
+	cd->dsb = wait_dsb();
+}
+
+void play_from_to_track(int from, int to)
+{
+	uch play_command[8] = { c_play, };
+	int i;
+
+	if (from == 0) {	/* continue paused play */
+		for (i = 0; i < 3; i++) {
+			play_command[i + 1] = cd->audio_status[i + 2];
+			play_command[i + 4] = PLAY_TO.fsm[i];
+		}
+	} else {
+		update_toc_entry(from);
+		update_toc_entry(to + 1);
+		for (i = 0; i < 3; i++) {
+			play_command[i + 1] = cd->toc[from].fsm[i];
+			PLAY_TO.fsm[i] = play_command[i + 4] =
+			    cd->toc[to + 1].fsm[i];
+		}
+		PLAY_TO.track = to;
+	}
+	for (i = 0; i < 7; i++)
+		type_0_command(play_command[i], 0);
+	for (i = 0; i < 2; i++)
+		type_0_command(0x2, 0);	/* volume */
+	cd->dsb = wait_dsb();
+}
+
+int get_current_q(struct cdrom_subchnl *qp)
+{
+	int i;
+	uch *q = cd->q;
+	if (type_1_command(c_read_current_q, 10, q))
+		return 0;
+/*  q[0] = bcdbin(q[0]); Don't think so! */
+	for (i = 2; i < 6; i++)
+		q[i] = bcdbin(q[i]);
+	qp->cdsc_adr = q[0] & 0xf;
+	qp->cdsc_ctrl = q[0] >> 4;	/* from mcd.c */
+	qp->cdsc_trk = q[1];
+	qp->cdsc_ind = q[2];
+	if (qp->cdsc_format == CDROM_MSF) {