Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / block / paride / pd.c
diff --git a/kernel/drivers/block/paride/pd.c b/kernel/drivers/block/paride/pd.c
new file mode 100644 (file)
index 0000000..d48715b
--- /dev/null
@@ -0,0 +1,958 @@
+/* 
+        pd.c    (c) 1997-8  Grant R. Guenther <grant@torque.net>
+                            Under the terms of the GNU General Public License.
+
+        This is the high-level driver for parallel port IDE hard
+        drives based on chips supported by the paride module.
+
+       By default, the driver will autoprobe for a single parallel
+       port IDE drive, but if their individual parameters are
+        specified, the driver can handle up to 4 drives.
+
+        The behaviour of the pd driver can be altered by setting
+        some parameters from the insmod command line.  The following
+        parameters are adjustable:
+           drive0      These four arguments can be arrays of       
+           drive1      1-8 integers as follows:
+           drive2
+           drive3      <prt>,<pro>,<uni>,<mod>,<geo>,<sby>,<dly>,<slv>
+
+                       Where,
+
+               <prt>   is the base of the parallel port address for
+                       the corresponding drive.  (required)
+
+               <pro>   is the protocol number for the adapter that
+                       supports this drive.  These numbers are
+                        logged by 'paride' when the protocol modules
+                       are initialised.  (0 if not given)
+
+               <uni>   for those adapters that support chained
+                       devices, this is the unit selector for the
+                       chain of devices on the given port.  It should
+                       be zero for devices that don't support chaining.
+                       (0 if not given)
+
+               <mod>   this can be -1 to choose the best mode, or one
+                       of the mode numbers supported by the adapter.
+                       (-1 if not given)
+
+               <geo>   this defaults to 0 to indicate that the driver
+                       should use the CHS geometry provided by the drive
+                       itself.  If set to 1, the driver will provide
+                       a logical geometry with 64 heads and 32 sectors
+                       per track, to be consistent with most SCSI
+                       drivers.  (0 if not given)
+
+               <sby>   set this to zero to disable the power saving
+                       standby mode, if needed.  (1 if not given)
+
+               <dly>   some parallel ports require the driver to 
+                       go more slowly.  -1 sets a default value that
+                       should work with the chosen protocol.  Otherwise,
+                       set this to a small integer, the larger it is
+                       the slower the port i/o.  In some cases, setting
+                       this to zero will speed up the device. (default -1)
+
+               <slv>   IDE disks can be jumpered to master or slave.
+                        Set this to 0 to choose the master drive, 1 to
+                        choose the slave, -1 (the default) to choose the
+                        first drive found.
+                       
+
+            major       You may use this parameter to overide the
+                        default major number (45) that this driver
+                        will use.  Be sure to change the device
+                        name as well.
+
+            name        This parameter is a character string that
+                        contains the name the kernel will use for this
+                        device (in /proc output, for instance).
+                       (default "pd")
+
+           cluster     The driver will attempt to aggregate requests
+                       for adjacent blocks into larger multi-block
+                       clusters.  The maximum cluster size (in 512
+                       byte sectors) is set with this parameter.
+                       (default 64)
+
+           verbose     This parameter controls the amount of logging
+                       that the driver will do.  Set it to 0 for 
+                       normal operation, 1 to see autoprobe progress
+                       messages, or 2 to see additional debugging
+                       output.  (default 0)
+
+            nice        This parameter controls the driver's use of
+                        idle CPU time, at the expense of some speed.
+
+        If this driver is built into the kernel, you can use kernel
+        the following command line parameters, with the same values
+        as the corresponding module parameters listed above:
+
+            pd.drive0
+            pd.drive1
+            pd.drive2
+            pd.drive3
+            pd.cluster
+            pd.nice
+
+        In addition, you can use the parameter pd.disable to disable
+        the driver entirely.
+*/
+
+/* Changes:
+
+       1.01    GRG 1997.01.24  Restored pd_reset()
+                               Added eject ioctl
+       1.02    GRG 1998.05.06  SMP spinlock changes, 
+                               Added slave support
+       1.03    GRG 1998.06.16  Eliminate an Ugh.
+       1.04    GRG 1998.08.15  Extra debugging, use HZ in loop timing
+       1.05    GRG 1998.09.24  Added jumbo support
+
+*/
+
+#define PD_VERSION      "1.05"
+#define PD_MAJOR       45
+#define PD_NAME                "pd"
+#define PD_UNITS       4
+
+/* Here are things one can override from the insmod command.
+   Most are autoprobed by paride unless set here.  Verbose is off
+   by default.
+
+*/
+#include <linux/types.h>
+
+static bool verbose = 0;
+static int major = PD_MAJOR;
+static char *name = PD_NAME;
+static int cluster = 64;
+static int nice = 0;
+static int disable = 0;
+
+static int drive0[8] = { 0, 0, 0, -1, 0, 1, -1, -1 };
+static int drive1[8] = { 0, 0, 0, -1, 0, 1, -1, -1 };
+static int drive2[8] = { 0, 0, 0, -1, 0, 1, -1, -1 };
+static int drive3[8] = { 0, 0, 0, -1, 0, 1, -1, -1 };
+
+static int (*drives[4])[8] = {&drive0, &drive1, &drive2, &drive3};
+
+enum {D_PRT, D_PRO, D_UNI, D_MOD, D_GEO, D_SBY, D_DLY, D_SLV};
+
+/* end of parameters */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/gfp.h>
+#include <linux/fs.h>
+#include <linux/delay.h>
+#include <linux/hdreg.h>
+#include <linux/cdrom.h>       /* for the eject ioctl */
+#include <linux/blkdev.h>
+#include <linux/blkpg.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <asm/uaccess.h>
+#include <linux/workqueue.h>
+
+static DEFINE_MUTEX(pd_mutex);
+static DEFINE_SPINLOCK(pd_lock);
+
+module_param(verbose, bool, 0);
+module_param(major, int, 0);
+module_param(name, charp, 0);
+module_param(cluster, int, 0);
+module_param(nice, int, 0);
+module_param_array(drive0, int, NULL, 0);
+module_param_array(drive1, int, NULL, 0);
+module_param_array(drive2, int, NULL, 0);
+module_param_array(drive3, int, NULL, 0);
+
+#include "paride.h"
+
+#define PD_BITS    4
+
+/* numbers for "SCSI" geometry */
+
+#define PD_LOG_HEADS    64
+#define PD_LOG_SECTS    32
+
+#define PD_ID_OFF       54
+#define PD_ID_LEN       14
+
+#define PD_MAX_RETRIES  5
+#define PD_TMO          800    /* interrupt timeout in jiffies */
+#define PD_SPIN_DEL     50     /* spin delay in micro-seconds  */
+
+#define PD_SPIN         (1000000*PD_TMO)/(HZ*PD_SPIN_DEL)
+
+#define STAT_ERR        0x00001
+#define STAT_INDEX      0x00002
+#define STAT_ECC        0x00004
+#define STAT_DRQ        0x00008
+#define STAT_SEEK       0x00010
+#define STAT_WRERR      0x00020
+#define STAT_READY      0x00040
+#define STAT_BUSY       0x00080
+
+#define ERR_AMNF        0x00100
+#define ERR_TK0NF       0x00200
+#define ERR_ABRT        0x00400
+#define ERR_MCR         0x00800
+#define ERR_IDNF        0x01000
+#define ERR_MC          0x02000
+#define ERR_UNC         0x04000
+#define ERR_TMO         0x10000
+
+#define IDE_READ               0x20
+#define IDE_WRITE              0x30
+#define IDE_READ_VRFY          0x40
+#define IDE_INIT_DEV_PARMS     0x91
+#define IDE_STANDBY            0x96
+#define IDE_ACKCHANGE          0xdb
+#define IDE_DOORLOCK           0xde
+#define IDE_DOORUNLOCK         0xdf
+#define IDE_IDENTIFY           0xec
+#define IDE_EJECT              0xed
+
+#define PD_NAMELEN     8
+
+struct pd_unit {
+       struct pi_adapter pia;  /* interface to paride layer */
+       struct pi_adapter *pi;
+       int access;             /* count of active opens ... */
+       int capacity;           /* Size of this volume in sectors */
+       int heads;              /* physical geometry */
+       int sectors;
+       int cylinders;
+       int can_lba;
+       int drive;              /* master=0 slave=1 */
+       int changed;            /* Have we seen a disk change ? */
+       int removable;          /* removable media device  ?  */
+       int standby;
+       int alt_geom;
+       char name[PD_NAMELEN];  /* pda, pdb, etc ... */
+       struct gendisk *gd;
+};
+
+static struct pd_unit pd[PD_UNITS];
+
+static char pd_scratch[512];   /* scratch block buffer */
+
+static char *pd_errs[17] = { "ERR", "INDEX", "ECC", "DRQ", "SEEK", "WRERR",
+       "READY", "BUSY", "AMNF", "TK0NF", "ABRT", "MCR",
+       "IDNF", "MC", "UNC", "???", "TMO"
+};
+
+static inline int status_reg(struct pd_unit *disk)
+{
+       return pi_read_regr(disk->pi, 1, 6);
+}
+
+static inline int read_reg(struct pd_unit *disk, int reg)
+{
+       return pi_read_regr(disk->pi, 0, reg);
+}
+
+static inline void write_status(struct pd_unit *disk, int val)
+{
+       pi_write_regr(disk->pi, 1, 6, val);
+}
+
+static inline void write_reg(struct pd_unit *disk, int reg, int val)
+{
+       pi_write_regr(disk->pi, 0, reg, val);
+}
+
+static inline u8 DRIVE(struct pd_unit *disk)
+{
+       return 0xa0+0x10*disk->drive;
+}
+
+/*  ide command interface */
+
+static void pd_print_error(struct pd_unit *disk, char *msg, int status)
+{
+       int i;
+
+       printk("%s: %s: status = 0x%x =", disk->name, msg, status);
+       for (i = 0; i < ARRAY_SIZE(pd_errs); i++)
+               if (status & (1 << i))
+                       printk(" %s", pd_errs[i]);
+       printk("\n");
+}
+
+static void pd_reset(struct pd_unit *disk)
+{                              /* called only for MASTER drive */
+       write_status(disk, 4);
+       udelay(50);
+       write_status(disk, 0);
+       udelay(250);
+}
+
+#define DBMSG(msg)     ((verbose>1)?(msg):NULL)
+
+static int pd_wait_for(struct pd_unit *disk, int w, char *msg)
+{                              /* polled wait */
+       int k, r, e;
+
+       k = 0;
+       while (k < PD_SPIN) {
+               r = status_reg(disk);
+               k++;
+               if (((r & w) == w) && !(r & STAT_BUSY))
+                       break;
+               udelay(PD_SPIN_DEL);
+       }
+       e = (read_reg(disk, 1) << 8) + read_reg(disk, 7);
+       if (k >= PD_SPIN)
+               e |= ERR_TMO;
+       if ((e & (STAT_ERR | ERR_TMO)) && (msg != NULL))
+               pd_print_error(disk, msg, e);
+       return e;
+}
+
+static void pd_send_command(struct pd_unit *disk, int n, int s, int h, int c0, int c1, int func)
+{
+       write_reg(disk, 6, DRIVE(disk) + h);
+       write_reg(disk, 1, 0);          /* the IDE task file */
+       write_reg(disk, 2, n);
+       write_reg(disk, 3, s);
+       write_reg(disk, 4, c0);
+       write_reg(disk, 5, c1);
+       write_reg(disk, 7, func);
+
+       udelay(1);
+}
+
+static void pd_ide_command(struct pd_unit *disk, int func, int block, int count)
+{
+       int c1, c0, h, s;
+
+       if (disk->can_lba) {
+               s = block & 255;
+               c0 = (block >>= 8) & 255;
+               c1 = (block >>= 8) & 255;
+               h = ((block >>= 8) & 15) + 0x40;
+       } else {
+               s = (block % disk->sectors) + 1;
+               h = (block /= disk->sectors) % disk->heads;
+               c0 = (block /= disk->heads) % 256;
+               c1 = (block >>= 8);
+       }
+       pd_send_command(disk, count, s, h, c0, c1, func);
+}
+
+/* The i/o request engine */
+
+enum action {Fail = 0, Ok = 1, Hold, Wait};
+
+static struct request *pd_req; /* current request */
+static enum action (*phase)(void);
+
+static void run_fsm(void);
+
+static void ps_tq_int(struct work_struct *work);
+
+static DECLARE_DELAYED_WORK(fsm_tq, ps_tq_int);
+
+static void schedule_fsm(void)
+{
+       if (!nice)
+               schedule_delayed_work(&fsm_tq, 0);
+       else
+               schedule_delayed_work(&fsm_tq, nice-1);
+}
+
+static void ps_tq_int(struct work_struct *work)
+{
+       run_fsm();
+}
+
+static enum action do_pd_io_start(void);
+static enum action pd_special(void);
+static enum action do_pd_read_start(void);
+static enum action do_pd_write_start(void);
+static enum action do_pd_read_drq(void);
+static enum action do_pd_write_done(void);
+
+static struct request_queue *pd_queue;
+static int pd_claimed;
+
+static struct pd_unit *pd_current; /* current request's drive */
+static PIA *pi_current; /* current request's PIA */
+
+static void run_fsm(void)
+{
+       while (1) {
+               enum action res;
+               unsigned long saved_flags;
+               int stop = 0;
+
+               if (!phase) {
+                       pd_current = pd_req->rq_disk->private_data;
+                       pi_current = pd_current->pi;
+                       phase = do_pd_io_start;
+               }
+
+               switch (pd_claimed) {
+                       case 0:
+                               pd_claimed = 1;
+                               if (!pi_schedule_claimed(pi_current, run_fsm))
+                                       return;
+                       case 1:
+                               pd_claimed = 2;
+                               pi_current->proto->connect(pi_current);
+               }
+
+               switch(res = phase()) {
+                       case Ok: case Fail:
+                               pi_disconnect(pi_current);
+                               pd_claimed = 0;
+                               phase = NULL;
+                               spin_lock_irqsave(&pd_lock, saved_flags);
+                               if (!__blk_end_request_cur(pd_req,
+                                               res == Ok ? 0 : -EIO)) {
+                                       pd_req = blk_fetch_request(pd_queue);
+                                       if (!pd_req)
+                                               stop = 1;
+                               }
+                               spin_unlock_irqrestore(&pd_lock, saved_flags);
+                               if (stop)
+                                       return;
+                       case Hold:
+                               schedule_fsm();
+                               return;
+                       case Wait:
+                               pi_disconnect(pi_current);
+                               pd_claimed = 0;
+               }
+       }
+}
+
+static int pd_retries = 0;     /* i/o error retry count */
+static int pd_block;           /* address of next requested block */
+static int pd_count;           /* number of blocks still to do */
+static int pd_run;             /* sectors in current cluster */
+static int pd_cmd;             /* current command READ/WRITE */
+static char *pd_buf;           /* buffer for request in progress */
+
+static enum action do_pd_io_start(void)
+{
+       if (pd_req->cmd_type == REQ_TYPE_SPECIAL) {
+               phase = pd_special;
+               return pd_special();
+       }
+
+       pd_cmd = rq_data_dir(pd_req);
+       if (pd_cmd == READ || pd_cmd == WRITE) {
+               pd_block = blk_rq_pos(pd_req);
+               pd_count = blk_rq_cur_sectors(pd_req);
+               if (pd_block + pd_count > get_capacity(pd_req->rq_disk))
+                       return Fail;
+               pd_run = blk_rq_sectors(pd_req);
+               pd_buf = bio_data(pd_req->bio);
+               pd_retries = 0;
+               if (pd_cmd == READ)
+                       return do_pd_read_start();
+               else
+                       return do_pd_write_start();
+       }
+       return Fail;
+}
+
+static enum action pd_special(void)
+{
+       enum action (*func)(struct pd_unit *) = pd_req->special;
+       return func(pd_current);
+}
+
+static int pd_next_buf(void)
+{
+       unsigned long saved_flags;
+
+       pd_count--;
+       pd_run--;
+       pd_buf += 512;
+       pd_block++;
+       if (!pd_run)
+               return 1;
+       if (pd_count)
+               return 0;
+       spin_lock_irqsave(&pd_lock, saved_flags);
+       __blk_end_request_cur(pd_req, 0);
+       pd_count = blk_rq_cur_sectors(pd_req);
+       pd_buf = bio_data(pd_req->bio);
+       spin_unlock_irqrestore(&pd_lock, saved_flags);
+       return 0;
+}
+
+static unsigned long pd_timeout;
+
+static enum action do_pd_read_start(void)
+{
+       if (pd_wait_for(pd_current, STAT_READY, "do_pd_read") & STAT_ERR) {
+               if (pd_retries < PD_MAX_RETRIES) {
+                       pd_retries++;
+                       return Wait;
+               }
+               return Fail;
+       }
+       pd_ide_command(pd_current, IDE_READ, pd_block, pd_run);
+       phase = do_pd_read_drq;
+       pd_timeout = jiffies + PD_TMO;
+       return Hold;
+}
+
+static enum action do_pd_write_start(void)
+{
+       if (pd_wait_for(pd_current, STAT_READY, "do_pd_write") & STAT_ERR) {
+               if (pd_retries < PD_MAX_RETRIES) {
+                       pd_retries++;
+                       return Wait;
+               }
+               return Fail;
+       }
+       pd_ide_command(pd_current, IDE_WRITE, pd_block, pd_run);
+       while (1) {
+               if (pd_wait_for(pd_current, STAT_DRQ, "do_pd_write_drq") & STAT_ERR) {
+                       if (pd_retries < PD_MAX_RETRIES) {
+                               pd_retries++;
+                               return Wait;
+                       }
+                       return Fail;
+               }
+               pi_write_block(pd_current->pi, pd_buf, 512);
+               if (pd_next_buf())
+                       break;
+       }
+       phase = do_pd_write_done;
+       pd_timeout = jiffies + PD_TMO;
+       return Hold;
+}
+
+static inline int pd_ready(void)
+{
+       return !(status_reg(pd_current) & STAT_BUSY);
+}
+
+static enum action do_pd_read_drq(void)
+{
+       if (!pd_ready() && !time_after_eq(jiffies, pd_timeout))
+               return Hold;
+
+       while (1) {
+               if (pd_wait_for(pd_current, STAT_DRQ, "do_pd_read_drq") & STAT_ERR) {
+                       if (pd_retries < PD_MAX_RETRIES) {
+                               pd_retries++;
+                               phase = do_pd_read_start;
+                               return Wait;
+                       }
+                       return Fail;
+               }
+               pi_read_block(pd_current->pi, pd_buf, 512);
+               if (pd_next_buf())
+                       break;
+       }
+       return Ok;
+}
+
+static enum action do_pd_write_done(void)
+{
+       if (!pd_ready() && !time_after_eq(jiffies, pd_timeout))
+               return Hold;
+
+       if (pd_wait_for(pd_current, STAT_READY, "do_pd_write_done") & STAT_ERR) {
+               if (pd_retries < PD_MAX_RETRIES) {
+                       pd_retries++;
+                       phase = do_pd_write_start;
+                       return Wait;
+               }
+               return Fail;
+       }
+       return Ok;
+}
+
+/* special io requests */
+
+/* According to the ATA standard, the default CHS geometry should be
+   available following a reset.  Some Western Digital drives come up
+   in a mode where only LBA addresses are accepted until the device
+   parameters are initialised.
+*/
+
+static void pd_init_dev_parms(struct pd_unit *disk)
+{
+       pd_wait_for(disk, 0, DBMSG("before init_dev_parms"));
+       pd_send_command(disk, disk->sectors, 0, disk->heads - 1, 0, 0,
+                       IDE_INIT_DEV_PARMS);
+       udelay(300);
+       pd_wait_for(disk, 0, "Initialise device parameters");
+}
+
+static enum action pd_door_lock(struct pd_unit *disk)
+{
+       if (!(pd_wait_for(disk, STAT_READY, "Lock") & STAT_ERR)) {
+               pd_send_command(disk, 1, 0, 0, 0, 0, IDE_DOORLOCK);
+               pd_wait_for(disk, STAT_READY, "Lock done");
+       }
+       return Ok;
+}
+
+static enum action pd_door_unlock(struct pd_unit *disk)
+{
+       if (!(pd_wait_for(disk, STAT_READY, "Lock") & STAT_ERR)) {
+               pd_send_command(disk, 1, 0, 0, 0, 0, IDE_DOORUNLOCK);
+               pd_wait_for(disk, STAT_READY, "Lock done");
+       }
+       return Ok;
+}
+
+static enum action pd_eject(struct pd_unit *disk)
+{
+       pd_wait_for(disk, 0, DBMSG("before unlock on eject"));
+       pd_send_command(disk, 1, 0, 0, 0, 0, IDE_DOORUNLOCK);
+       pd_wait_for(disk, 0, DBMSG("after unlock on eject"));
+       pd_wait_for(disk, 0, DBMSG("before eject"));
+       pd_send_command(disk, 0, 0, 0, 0, 0, IDE_EJECT);
+       pd_wait_for(disk, 0, DBMSG("after eject"));
+       return Ok;
+}
+
+static enum action pd_media_check(struct pd_unit *disk)
+{
+       int r = pd_wait_for(disk, STAT_READY, DBMSG("before media_check"));
+       if (!(r & STAT_ERR)) {
+               pd_send_command(disk, 1, 1, 0, 0, 0, IDE_READ_VRFY);
+               r = pd_wait_for(disk, STAT_READY, DBMSG("RDY after READ_VRFY"));
+       } else
+               disk->changed = 1;      /* say changed if other error */
+       if (r & ERR_MC) {
+               disk->changed = 1;
+               pd_send_command(disk, 1, 0, 0, 0, 0, IDE_ACKCHANGE);
+               pd_wait_for(disk, STAT_READY, DBMSG("RDY after ACKCHANGE"));
+               pd_send_command(disk, 1, 1, 0, 0, 0, IDE_READ_VRFY);
+               r = pd_wait_for(disk, STAT_READY, DBMSG("RDY after VRFY"));
+       }
+       return Ok;
+}
+
+static void pd_standby_off(struct pd_unit *disk)
+{
+       pd_wait_for(disk, 0, DBMSG("before STANDBY"));
+       pd_send_command(disk, 0, 0, 0, 0, 0, IDE_STANDBY);
+       pd_wait_for(disk, 0, DBMSG("after STANDBY"));
+}
+
+static enum action pd_identify(struct pd_unit *disk)
+{
+       int j;
+       char id[PD_ID_LEN + 1];
+
+/* WARNING:  here there may be dragons.  reset() applies to both drives,
+   but we call it only on probing the MASTER. This should allow most
+   common configurations to work, but be warned that a reset can clear
+   settings on the SLAVE drive.
+*/
+
+       if (disk->drive == 0)
+               pd_reset(disk);
+
+       write_reg(disk, 6, DRIVE(disk));
+       pd_wait_for(disk, 0, DBMSG("before IDENT"));
+       pd_send_command(disk, 1, 0, 0, 0, 0, IDE_IDENTIFY);
+
+       if (pd_wait_for(disk, STAT_DRQ, DBMSG("IDENT DRQ")) & STAT_ERR)
+               return Fail;
+       pi_read_block(disk->pi, pd_scratch, 512);
+       disk->can_lba = pd_scratch[99] & 2;
+       disk->sectors = le16_to_cpu(*(__le16 *) (pd_scratch + 12));
+       disk->heads = le16_to_cpu(*(__le16 *) (pd_scratch + 6));
+       disk->cylinders = le16_to_cpu(*(__le16 *) (pd_scratch + 2));
+       if (disk->can_lba)
+               disk->capacity = le32_to_cpu(*(__le32 *) (pd_scratch + 120));
+       else
+               disk->capacity = disk->sectors * disk->heads * disk->cylinders;
+
+       for (j = 0; j < PD_ID_LEN; j++)
+               id[j ^ 1] = pd_scratch[j + PD_ID_OFF];
+       j = PD_ID_LEN - 1;
+       while ((j >= 0) && (id[j] <= 0x20))
+               j--;
+       j++;
+       id[j] = 0;
+
+       disk->removable = pd_scratch[0] & 0x80;
+
+       printk("%s: %s, %s, %d blocks [%dM], (%d/%d/%d), %s media\n",
+              disk->name, id,
+              disk->drive ? "slave" : "master",
+              disk->capacity, disk->capacity / 2048,
+              disk->cylinders, disk->heads, disk->sectors,
+              disk->removable ? "removable" : "fixed");
+
+       if (disk->capacity)
+               pd_init_dev_parms(disk);
+       if (!disk->standby)
+               pd_standby_off(disk);
+
+       return Ok;
+}
+
+/* end of io request engine */
+
+static void do_pd_request(struct request_queue * q)
+{
+       if (pd_req)
+               return;
+       pd_req = blk_fetch_request(q);
+       if (!pd_req)
+               return;
+
+       schedule_fsm();
+}
+
+static int pd_special_command(struct pd_unit *disk,
+                     enum action (*func)(struct pd_unit *disk))
+{
+       struct request *rq;
+       int err = 0;
+
+       rq = blk_get_request(disk->gd->queue, READ, __GFP_WAIT);
+       if (IS_ERR(rq))
+               return PTR_ERR(rq);
+
+       rq->cmd_type = REQ_TYPE_SPECIAL;
+       rq->special = func;
+
+       err = blk_execute_rq(disk->gd->queue, disk->gd, rq, 0);
+
+       blk_put_request(rq);
+       return err;
+}
+
+/* kernel glue structures */
+
+static int pd_open(struct block_device *bdev, fmode_t mode)
+{
+       struct pd_unit *disk = bdev->bd_disk->private_data;
+
+       mutex_lock(&pd_mutex);
+       disk->access++;
+
+       if (disk->removable) {
+               pd_special_command(disk, pd_media_check);
+               pd_special_command(disk, pd_door_lock);
+       }
+       mutex_unlock(&pd_mutex);
+       return 0;
+}
+
+static int pd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+       struct pd_unit *disk = bdev->bd_disk->private_data;
+
+       if (disk->alt_geom) {
+               geo->heads = PD_LOG_HEADS;
+               geo->sectors = PD_LOG_SECTS;
+               geo->cylinders = disk->capacity / (geo->heads * geo->sectors);
+       } else {
+               geo->heads = disk->heads;
+               geo->sectors = disk->sectors;
+               geo->cylinders = disk->cylinders;
+       }
+
+       return 0;
+}
+
+static int pd_ioctl(struct block_device *bdev, fmode_t mode,
+        unsigned int cmd, unsigned long arg)
+{
+       struct pd_unit *disk = bdev->bd_disk->private_data;
+
+       switch (cmd) {
+       case CDROMEJECT:
+               mutex_lock(&pd_mutex);
+               if (disk->access == 1)
+                       pd_special_command(disk, pd_eject);
+               mutex_unlock(&pd_mutex);
+               return 0;
+       default:
+               return -EINVAL;
+       }
+}
+
+static void pd_release(struct gendisk *p, fmode_t mode)
+{
+       struct pd_unit *disk = p->private_data;
+
+       mutex_lock(&pd_mutex);
+       if (!--disk->access && disk->removable)
+               pd_special_command(disk, pd_door_unlock);
+       mutex_unlock(&pd_mutex);
+}
+
+static unsigned int pd_check_events(struct gendisk *p, unsigned int clearing)
+{
+       struct pd_unit *disk = p->private_data;
+       int r;
+       if (!disk->removable)
+               return 0;
+       pd_special_command(disk, pd_media_check);
+       r = disk->changed;
+       disk->changed = 0;
+       return r ? DISK_EVENT_MEDIA_CHANGE : 0;
+}
+
+static int pd_revalidate(struct gendisk *p)
+{
+       struct pd_unit *disk = p->private_data;
+       if (pd_special_command(disk, pd_identify) == 0)
+               set_capacity(p, disk->capacity);
+       else
+               set_capacity(p, 0);
+       return 0;
+}
+
+static const struct block_device_operations pd_fops = {
+       .owner          = THIS_MODULE,
+       .open           = pd_open,
+       .release        = pd_release,
+       .ioctl          = pd_ioctl,
+       .getgeo         = pd_getgeo,
+       .check_events   = pd_check_events,
+       .revalidate_disk= pd_revalidate
+};
+
+/* probing */
+
+static void pd_probe_drive(struct pd_unit *disk)
+{
+       struct gendisk *p = alloc_disk(1 << PD_BITS);
+       if (!p)
+               return;
+       strcpy(p->disk_name, disk->name);
+       p->fops = &pd_fops;
+       p->major = major;
+       p->first_minor = (disk - pd) << PD_BITS;
+       disk->gd = p;
+       p->private_data = disk;
+       p->queue = pd_queue;
+
+       if (disk->drive == -1) {
+               for (disk->drive = 0; disk->drive <= 1; disk->drive++)
+                       if (pd_special_command(disk, pd_identify) == 0)
+                               return;
+       } else if (pd_special_command(disk, pd_identify) == 0)
+               return;
+       disk->gd = NULL;
+       put_disk(p);
+}
+
+static int pd_detect(void)
+{
+       int found = 0, unit, pd_drive_count = 0;
+       struct pd_unit *disk;
+
+       for (unit = 0; unit < PD_UNITS; unit++) {
+               int *parm = *drives[unit];
+               struct pd_unit *disk = pd + unit;
+               disk->pi = &disk->pia;
+               disk->access = 0;
+               disk->changed = 1;
+               disk->capacity = 0;
+               disk->drive = parm[D_SLV];
+               snprintf(disk->name, PD_NAMELEN, "%s%c", name, 'a'+unit);
+               disk->alt_geom = parm[D_GEO];
+               disk->standby = parm[D_SBY];
+               if (parm[D_PRT])
+                       pd_drive_count++;
+       }
+
+       if (pd_drive_count == 0) { /* nothing spec'd - so autoprobe for 1 */
+               disk = pd;
+               if (pi_init(disk->pi, 1, -1, -1, -1, -1, -1, pd_scratch,
+                           PI_PD, verbose, disk->name)) {
+                       pd_probe_drive(disk);
+                       if (!disk->gd)
+                               pi_release(disk->pi);
+               }
+
+       } else {
+               for (unit = 0, disk = pd; unit < PD_UNITS; unit++, disk++) {
+                       int *parm = *drives[unit];
+                       if (!parm[D_PRT])
+                               continue;
+                       if (pi_init(disk->pi, 0, parm[D_PRT], parm[D_MOD],
+                                    parm[D_UNI], parm[D_PRO], parm[D_DLY],
+                                    pd_scratch, PI_PD, verbose, disk->name)) {
+                               pd_probe_drive(disk);
+                               if (!disk->gd)
+                                       pi_release(disk->pi);
+                       }
+               }
+       }
+       for (unit = 0, disk = pd; unit < PD_UNITS; unit++, disk++) {
+               if (disk->gd) {
+                       set_capacity(disk->gd, disk->capacity);
+                       add_disk(disk->gd);
+                       found = 1;
+               }
+       }
+       if (!found)
+               printk("%s: no valid drive found\n", name);
+       return found;
+}
+
+static int __init pd_init(void)
+{
+       if (disable)
+               goto out1;
+
+       pd_queue = blk_init_queue(do_pd_request, &pd_lock);
+       if (!pd_queue)
+               goto out1;
+
+       blk_queue_max_hw_sectors(pd_queue, cluster);
+
+       if (register_blkdev(major, name))
+               goto out2;
+
+       printk("%s: %s version %s, major %d, cluster %d, nice %d\n",
+              name, name, PD_VERSION, major, cluster, nice);
+       if (!pd_detect())
+               goto out3;
+
+       return 0;
+
+out3:
+       unregister_blkdev(major, name);
+out2:
+       blk_cleanup_queue(pd_queue);
+out1:
+       return -ENODEV;
+}
+
+static void __exit pd_exit(void)
+{
+       struct pd_unit *disk;
+       int unit;
+       unregister_blkdev(major, name);
+       for (unit = 0, disk = pd; unit < PD_UNITS; unit++, disk++) {
+               struct gendisk *p = disk->gd;
+               if (p) {
+                       disk->gd = NULL;
+                       del_gendisk(p);
+                       put_disk(p);
+                       pi_release(disk->pi);
+               }
+       }
+       blk_cleanup_queue(pd_queue);
+}
+
+MODULE_LICENSE("GPL");
+module_init(pd_init)
+module_exit(pd_exit)