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minix/drivers/floppy/floppy.c
Philip Homburg aeb6630868 Ignore SIGHUP in floppy driver.
2006-05-11 14:52:40 +00:00

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/* This file contains the device dependent part of the driver for the Floppy
* Disk Controller (FDC) using the NEC PD765 chip.
*
* The file contains two entry points:
*
* floppy_task: main entry when system is brought up
*
* Changes:
* Sep 11, 2005 code cleanup (Andy Tanenbaum)
* Dec 01, 2004 floppy driver moved to user-space (Jorrit N. Herder)
* Sep 15, 2004 sync alarms/ local timer management (Jorrit N. Herder)
* Aug 12, 2003 null seek no interrupt fix (Mike Haertel)
* May 14, 2000 d-d/i rewrite (Kees J. Bot)
* Apr 04, 1992 device dependent/independent split (Kees J. Bot)
* Mar 27, 1992 last details on density checking (Kees J. Bot)
* Feb 14, 1992 check drive density on opens only (Andy Tanenbaum)
* 1991 len[] / motors / reset / step rate / ... (Bruce Evans)
* May 13, 1991 renovated the errors loop (Don Chapman)
* 1989 I/O vector to keep up with 1-1 interleave (Bruce Evans)
* Jan 06, 1988 allow 1.44 MB diskettes (Al Crew)
* Nov 28, 1986 better resetting for 386 (Peter Kay)
* Oct 27, 1986 fdc_results fixed for 8 MHz (Jakob Schripsema)
*/
#include "floppy.h"
#include <timers.h>
#include <ibm/diskparm.h>
#include <minix/sysutil.h>
#include <minix/syslib.h>
/* I/O Ports used by floppy disk task. */
#define DOR 0x3F2 /* motor drive control bits */
#define FDC_STATUS 0x3F4 /* floppy disk controller status register */
#define FDC_DATA 0x3F5 /* floppy disk controller data register */
#define FDC_RATE 0x3F7 /* transfer rate register */
#define DMA_ADDR 0x004 /* port for low 16 bits of DMA address */
#define DMA_TOP 0x081 /* port for top 8 bits of 24-bit DMA addr */
#define DMA_COUNT 0x005 /* port for DMA count (count = bytes - 1) */
#define DMA_FLIPFLOP 0x00C /* DMA byte pointer flip-flop */
#define DMA_MODE 0x00B /* DMA mode port */
#define DMA_INIT 0x00A /* DMA init port */
#define DMA_RESET_VAL 0x006
#define DMA_ADDR_MASK 0xFFFFFF /* mask to verify DMA address is 24-bit */
/* Status registers returned as result of operation. */
#define ST0 0x00 /* status register 0 */
#define ST1 0x01 /* status register 1 */
#define ST2 0x02 /* status register 2 */
#define ST3 0x00 /* status register 3 (return by DRIVE_SENSE) */
#define ST_CYL 0x03 /* slot where controller reports cylinder */
#define ST_HEAD 0x04 /* slot where controller reports head */
#define ST_SEC 0x05 /* slot where controller reports sector */
#define ST_PCN 0x01 /* slot where controller reports present cyl */
/* Fields within the I/O ports. */
/* Main status register. */
#define CTL_BUSY 0x10 /* bit is set when read or write in progress */
#define DIRECTION 0x40 /* bit is set when reading data reg is valid */
#define MASTER 0x80 /* bit is set when data reg can be accessed */
/* Digital output port (DOR). */
#define MOTOR_SHIFT 4 /* high 4 bits control the motors in DOR */
#define ENABLE_INT 0x0C /* used for setting DOR port */
/* ST0. */
#define ST0_BITS_TRANS 0xD8 /* check 4 bits of status */
#define TRANS_ST0 0x00 /* 4 bits of ST0 for READ/WRITE */
#define ST0_BITS_SEEK 0xF8 /* check top 5 bits of seek status */
#define SEEK_ST0 0x20 /* top 5 bits of ST0 for SEEK */
/* ST1. */
#define BAD_SECTOR 0x05 /* if these bits are set in ST1, recalibrate */
#define WRITE_PROTECT 0x02 /* bit is set if diskette is write protected */
/* ST2. */
#define BAD_CYL 0x1F /* if any of these bits are set, recalibrate */
/* ST3 (not used). */
#define ST3_FAULT 0x80 /* if this bit is set, drive is sick */
#define ST3_WR_PROTECT 0x40 /* set when diskette is write protected */
#define ST3_READY 0x20 /* set when drive is ready */
/* Floppy disk controller command bytes. */
#define FDC_SEEK 0x0F /* command the drive to seek */
#define FDC_READ 0xE6 /* command the drive to read */
#define FDC_WRITE 0xC5 /* command the drive to write */
#define FDC_SENSE 0x08 /* command the controller to tell its status */
#define FDC_RECALIBRATE 0x07 /* command the drive to go to cyl 0 */
#define FDC_SPECIFY 0x03 /* command the drive to accept params */
#define FDC_READ_ID 0x4A /* command the drive to read sector identity */
#define FDC_FORMAT 0x4D /* command the drive to format a track */
/* DMA channel commands. */
#define DMA_READ 0x46 /* DMA read opcode */
#define DMA_WRITE 0x4A /* DMA write opcode */
/* Parameters for the disk drive. */
#define HC_SIZE 2880 /* # sectors on largest legal disk (1.44MB) */
#define NR_HEADS 0x02 /* two heads (i.e., two tracks/cylinder) */
#define MAX_SECTORS 18 /* largest # sectors per track */
#define DTL 0xFF /* determines data length (sector size) */
#define SPEC2 0x02 /* second parameter to SPECIFY */
#define MOTOR_OFF (3*HZ) /* how long to wait before stopping motor */
#define WAKEUP (2*HZ) /* timeout on I/O, FDC won't quit. */
/* Error codes */
#define ERR_SEEK (-1) /* bad seek */
#define ERR_TRANSFER (-2) /* bad transfer */
#define ERR_STATUS (-3) /* something wrong when getting status */
#define ERR_READ_ID (-4) /* bad read id */
#define ERR_RECALIBRATE (-5) /* recalibrate didn't work properly */
#define ERR_DRIVE (-6) /* something wrong with a drive */
#define ERR_WR_PROTECT (-7) /* diskette is write protected */
#define ERR_TIMEOUT (-8) /* interrupt timeout */
/* No retries on some errors. */
#define err_no_retry(err) ((err) <= ERR_WR_PROTECT)
/* Encoding of drive type in minor device number. */
#define DEV_TYPE_BITS 0x7C /* drive type + 1, if nonzero */
#define DEV_TYPE_SHIFT 2 /* right shift to normalize type bits */
#define FORMAT_DEV_BIT 0x80 /* bit in minor to turn write into format */
/* Miscellaneous. */
#define MAX_ERRORS 6 /* how often to try rd/wt before quitting */
#define MAX_RESULTS 7 /* max number of bytes controller returns */
#define NR_DRIVES 2 /* maximum number of drives */
#define DIVISOR 128 /* used for sector size encoding */
#define SECTOR_SIZE_CODE 2 /* code to say "512" to the controller */
#define TIMEOUT_MICROS 500000L /* microseconds waiting for FDC */
#define TIMEOUT_TICKS 30 /* ticks waiting for FDC */
#define NT 7 /* number of diskette/drive combinations */
#define UNCALIBRATED 0 /* drive needs to be calibrated at next use */
#define CALIBRATED 1 /* no calibration needed */
#define BASE_SECTOR 1 /* sectors are numbered starting at 1 */
#define NO_SECTOR (-1) /* current sector unknown */
#define NO_CYL (-1) /* current cylinder unknown, must seek */
#define NO_DENS 100 /* current media unknown */
#define BSY_IDLE 0 /* busy doing nothing */
#define BSY_IO 1 /* busy doing I/O */
#define BSY_WAKEN 2 /* got a wakeup call */
/* Seven combinations of diskette/drive are supported.
*
* # Diskette Drive Sectors Tracks Rotation Data-rate Comment
* 0 360K 360K 9 40 300 RPM 250 kbps Standard PC DSDD
* 1 1.2M 1.2M 15 80 360 RPM 500 kbps AT disk in AT drive
* 2 360K 720K 9 40 300 RPM 250 kbps Quad density PC
* 3 720K 720K 9 80 300 RPM 250 kbps Toshiba, et al.
* 4 360K 1.2M 9 40 360 RPM 300 kbps PC disk in AT drive
* 5 720K 1.2M 9 80 360 RPM 300 kbps Toshiba in AT drive
* 6 1.44M 1.44M 18 80 300 RPM 500 kbps PS/2, et al.
*
* In addition, 720K diskettes can be read in 1.44MB drives, but that does
* not need a different set of parameters. This combination uses
*
* 3 720K 1.44M 9 80 300 RPM 250 kbps PS/2, et al.
*/
PRIVATE struct density {
u8_t secpt; /* sectors per track */
u8_t cyls; /* tracks per side */
u8_t steps; /* steps per cylinder (2 = double step) */
u8_t test; /* sector to try for density test */
u8_t rate; /* data rate (2=250, 1=300, 0=500 kbps) */
u8_t start; /* motor start (clock ticks) */
u8_t gap; /* gap size */
u8_t spec1; /* first specify byte (SRT/HUT) */
} fdensity[NT] = {
{ 9, 40, 1, 4*9, 2, 4*HZ/8, 0x2A, 0xDF }, /* 360K / 360K */
{ 15, 80, 1, 14, 0, 4*HZ/8, 0x1B, 0xDF }, /* 1.2M / 1.2M */
{ 9, 40, 2, 2*9, 2, 4*HZ/8, 0x2A, 0xDF }, /* 360K / 720K */
{ 9, 80, 1, 4*9, 2, 6*HZ/8, 0x2A, 0xDF }, /* 720K / 720K */
{ 9, 40, 2, 2*9, 1, 4*HZ/8, 0x23, 0xDF }, /* 360K / 1.2M */
{ 9, 80, 1, 4*9, 1, 4*HZ/8, 0x23, 0xDF }, /* 720K / 1.2M */
{ 18, 80, 1, 17, 0, 6*HZ/8, 0x1B, 0xCF }, /* 1.44M / 1.44M */
};
/* The following table is used with the test_sector array to recognize a
* drive/floppy combination. The sector to test has been determined by
* looking at the differences in gap size, sectors/track, and double stepping.
* This means that types 0 and 3 can't be told apart, only the motor start
* time differs. If a read test succeeds then the drive is limited to the
* set of densities it can support to avoid unnecessary tests in the future.
*/
#define b(d) (1 << (d)) /* bit for density d. */
PRIVATE struct test_order {
u8_t t_density; /* floppy/drive type */
u8_t t_class; /* limit drive to this class of densities */
} test_order[NT-1] = {
{ 6, b(3) | b(6) }, /* 1.44M {720K, 1.44M} */
{ 1, b(1) | b(4) | b(5) }, /* 1.2M {1.2M, 360K, 720K} */
{ 3, b(2) | b(3) | b(6) }, /* 720K {360K, 720K, 1.44M} */
{ 4, b(1) | b(4) | b(5) }, /* 360K {1.2M, 360K, 720K} */
{ 5, b(1) | b(4) | b(5) }, /* 720K {1.2M, 360K, 720K} */
{ 2, b(2) | b(3) }, /* 360K {360K, 720K} */
/* Note that type 0 is missing, type 3 can read/write it too, which is
* why the type 3 parameters have been pessimized to be like type 0.
*/
};
/* Variables. */
PRIVATE struct floppy { /* main drive struct, one entry per drive */
unsigned fl_curcyl; /* current cylinder */
unsigned fl_hardcyl; /* hardware cylinder, as opposed to: */
unsigned fl_cylinder; /* cylinder number addressed */
unsigned fl_sector; /* sector addressed */
unsigned fl_head; /* head number addressed */
char fl_calibration; /* CALIBRATED or UNCALIBRATED */
u8_t fl_density; /* NO_DENS = ?, 0 = 360K; 1 = 360K/1.2M; etc.*/
u8_t fl_class; /* bitmap for possible densities */
timer_t fl_tmr_stop; /* timer to stop motor */
struct device fl_geom; /* Geometry of the drive */
struct device fl_part[NR_PARTITIONS]; /* partition's base & size */
} floppy[NR_DRIVES];
PRIVATE int irq_hook_id; /* id of irq hook at the kernel */
PRIVATE int motor_status; /* bitmap of current motor status */
PRIVATE int need_reset; /* set to 1 when controller must be reset */
PRIVATE unsigned f_drive; /* selected drive */
PRIVATE unsigned f_device; /* selected minor device */
PRIVATE struct floppy *f_fp; /* current drive */
PRIVATE struct density *f_dp; /* current density parameters */
PRIVATE struct density *prev_dp;/* previous density parameters */
PRIVATE unsigned f_sectors; /* equal to f_dp->secpt (needed a lot) */
PRIVATE u16_t f_busy; /* BSY_IDLE, BSY_IO, BSY_WAKEN */
PRIVATE struct device *f_dv; /* device's base and size */
PRIVATE struct disk_parameter_s fmt_param; /* parameters for format */
PRIVATE u8_t f_results[MAX_RESULTS];/* the controller can give lots of output */
/* The floppy uses various timers. These are managed by the floppy driver
* itself, because only a single synchronous alarm is available per process.
* Besides the 'f_tmr_timeout' timer below, the floppy structure for each
* floppy disk drive contains a 'fl_tmr_stop' timer.
*/
PRIVATE timer_t f_tmr_timeout; /* timer for various timeouts */
PRIVATE timer_t *f_timers; /* queue of floppy timers */
PRIVATE clock_t f_next_timeout; /* the next timeout time */
FORWARD _PROTOTYPE( void f_expire_tmrs, (struct driver *dp, message *m_ptr) );
FORWARD _PROTOTYPE( void f_set_timer, (timer_t *tp, clock_t delta,
tmr_func_t watchdog) );
FORWARD _PROTOTYPE( void stop_motor, (timer_t *tp) );
FORWARD _PROTOTYPE( void f_timeout, (timer_t *tp) );
FORWARD _PROTOTYPE( struct device *f_prepare, (int device) );
FORWARD _PROTOTYPE( char *f_name, (void) );
FORWARD _PROTOTYPE( void f_cleanup, (void) );
FORWARD _PROTOTYPE( int f_transfer, (int proc_nr, int opcode, off_t position,
iovec_t *iov, unsigned nr_req) );
FORWARD _PROTOTYPE( int dma_setup, (int opcode) );
FORWARD _PROTOTYPE( void start_motor, (void) );
FORWARD _PROTOTYPE( int seek, (void) );
FORWARD _PROTOTYPE( int fdc_transfer, (int opcode) );
FORWARD _PROTOTYPE( int fdc_results, (void) );
FORWARD _PROTOTYPE( int fdc_command, (u8_t *cmd, int len) );
FORWARD _PROTOTYPE( void fdc_out, (int val) );
FORWARD _PROTOTYPE( int recalibrate, (void) );
FORWARD _PROTOTYPE( void f_reset, (void) );
FORWARD _PROTOTYPE( int f_intr_wait, (void) );
FORWARD _PROTOTYPE( int read_id, (void) );
FORWARD _PROTOTYPE( int f_do_open, (struct driver *dp, message *m_ptr) );
FORWARD _PROTOTYPE( void floppy_stop, (struct driver *dp, message *m_ptr));
FORWARD _PROTOTYPE( int test_read, (int density) );
FORWARD _PROTOTYPE( void f_geometry, (struct partition *entry) );
/* Entry points to this driver. */
PRIVATE struct driver f_dtab = {
f_name, /* current device's name */
f_do_open, /* open or mount request, sense type of diskette */
do_nop, /* nothing on a close */
do_diocntl, /* get or set a partitions geometry */
f_prepare, /* prepare for I/O on a given minor device */
f_transfer, /* do the I/O */
f_cleanup, /* cleanup before sending reply to user process */
f_geometry, /* tell the geometry of the diskette */
floppy_stop, /* floppy cleanup on shutdown */
f_expire_tmrs,/* expire all alarm timers */
nop_cancel,
nop_select,
NULL,
NULL
};
/*===========================================================================*
* floppy_task *
*===========================================================================*/
PUBLIC void main()
{
/* Initialize the floppy structure and the timers. */
struct floppy *fp;
int s;
f_next_timeout = TMR_NEVER;
tmr_inittimer(&f_tmr_timeout);
for (fp = &floppy[0]; fp < &floppy[NR_DRIVES]; fp++) {
fp->fl_curcyl = NO_CYL;
fp->fl_density = NO_DENS;
fp->fl_class = ~0;
tmr_inittimer(&fp->fl_tmr_stop);
}
/* Set IRQ policy, only request notifications, do not automatically
* reenable interrupts. ID return on interrupt is the IRQ line number.
*/
irq_hook_id = FLOPPY_IRQ;
if ((s=sys_irqsetpolicy(FLOPPY_IRQ, 0, &irq_hook_id )) != OK)
panic("FLOPPY", "Couldn't set IRQ policy", s);
if ((s=sys_irqenable(&irq_hook_id)) != OK)
panic("FLOPPY", "Couldn't enable IRQs", s);
/* Ignore signals */
signal(SIGHUP, SIG_IGN);
driver_task(&f_dtab);
}
/*===========================================================================*
* f_expire_tmrs *
*===========================================================================*/
PRIVATE void f_expire_tmrs(struct driver *dp, message *m_ptr)
{
/* A synchronous alarm message was received. Check if there are any expired
* timers. Possibly reschedule the next alarm.
*/
clock_t now; /* current time */
timer_t *tp;
int s;
/* Get the current time to compare the timers against. */
if ((s=getuptime(&now)) != OK)
panic("FLOPPY","Couldn't get uptime from clock.", s);
/* Scan the timers queue for expired timers. Dispatch the watchdog function
* for each expired timers. FLOPPY watchdog functions are f_tmr_timeout()
* and stop_motor(). Possibly a new alarm call must be scheduled.
*/
tmrs_exptimers(&f_timers, now, NULL);
if (f_timers == NULL) {
f_next_timeout = TMR_NEVER;
} else { /* set new sync alarm */
f_next_timeout = f_timers->tmr_exp_time;
if ((s=sys_setalarm(f_next_timeout, 1)) != OK)
panic("FLOPPY","Couldn't set synchronous alarm.", s);
}
}
/*===========================================================================*
* f_set_timer *
*===========================================================================*/
PRIVATE void f_set_timer(tp, delta, watchdog)
timer_t *tp; /* timer to be set */
clock_t delta; /* in how many ticks */
tmr_func_t watchdog; /* watchdog function to be called */
{
clock_t now; /* current time */
int s;
/* Get the current time. */
if ((s=getuptime(&now)) != OK)
panic("FLOPPY","Couldn't get uptime from clock.", s);
/* Add the timer to the local timer queue. */
tmrs_settimer(&f_timers, tp, now + delta, watchdog, NULL);
/* Possibly reschedule an alarm call. This happens when the front of the
* timers queue was reinserted at another position, i.e., when a timer was
* reset, or when a new timer was added in front.
*/
if (f_timers->tmr_exp_time != f_next_timeout) {
f_next_timeout = f_timers->tmr_exp_time;
if ((s=sys_setalarm(f_next_timeout, 1)) != OK)
panic("FLOPPY","Couldn't set synchronous alarm.", s);
}
}
/*===========================================================================*
* f_prepare *
*===========================================================================*/
PRIVATE struct device *f_prepare(device)
int device;
{
/* Prepare for I/O on a device. */
f_device = device;
f_drive = device & ~(DEV_TYPE_BITS | FORMAT_DEV_BIT);
if (f_drive < 0 || f_drive >= NR_DRIVES) return(NIL_DEV);
f_fp = &floppy[f_drive];
f_dv = &f_fp->fl_geom;
if (f_fp->fl_density < NT) {
f_dp = &fdensity[f_fp->fl_density];
f_sectors = f_dp->secpt;
f_fp->fl_geom.dv_size = mul64u((long) (NR_HEADS * f_sectors
* f_dp->cyls), SECTOR_SIZE);
}
/* A partition? */
if ((device &= DEV_TYPE_BITS) >= MINOR_fd0p0)
f_dv = &f_fp->fl_part[(device - MINOR_fd0p0) >> DEV_TYPE_SHIFT];
return f_dv;
}
/*===========================================================================*
* f_name *
*===========================================================================*/
PRIVATE char *f_name()
{
/* Return a name for the current device. */
static char name[] = "fd0";
name[2] = '0' + f_drive;
return name;
}
/*===========================================================================*
* f_cleanup *
*===========================================================================*/
PRIVATE void f_cleanup()
{
/* Start a timer to turn the motor off in a few seconds. */
tmr_arg(&f_fp->fl_tmr_stop)->ta_int = f_drive;
f_set_timer(&f_fp->fl_tmr_stop, MOTOR_OFF, stop_motor);
/* Exiting the floppy driver, so forget where we are. */
f_fp->fl_sector = NO_SECTOR;
}
/*===========================================================================*
* f_transfer *
*===========================================================================*/
PRIVATE int f_transfer(proc_nr, opcode, position, iov, nr_req)
int proc_nr; /* process doing the request */
int opcode; /* DEV_GATHER or DEV_SCATTER */
off_t position; /* offset on device to read or write */
iovec_t *iov; /* pointer to read or write request vector */
unsigned nr_req; /* length of request vector */
{
struct floppy *fp = f_fp;
iovec_t *iop, *iov_end = iov + nr_req;
int s, r, errors;
unsigned block; /* Seen any 32M floppies lately? */
unsigned nbytes, count, chunk, sector;
unsigned long dv_size = cv64ul(f_dv->dv_size);
vir_bytes user_addr;
vir_bytes uaddrs[MAX_SECTORS], *up;
u8_t cmd[3];
/* Check disk address. */
if ((position & SECTOR_MASK) != 0) return(EINVAL);
#if 0 /* XXX hack to create a disk driver that crashes */
{ static int count= 0; if (++count > 10) {
printf("floppy: time to die\n"); *(int *)-1= 42;
}}
#endif
errors = 0;
while (nr_req > 0) {
/* How many bytes to transfer? */
nbytes = 0;
for (iop = iov; iop < iov_end; iop++) nbytes += iop->iov_size;
/* Which block on disk and how close to EOF? */
if (position >= dv_size) return(OK); /* At EOF */
if (position + nbytes > dv_size) nbytes = dv_size - position;
block = div64u(add64ul(f_dv->dv_base, position), SECTOR_SIZE);
if ((nbytes & SECTOR_MASK) != 0) return(EINVAL);
/* Using a formatting device? */
if (f_device & FORMAT_DEV_BIT) {
if (opcode != DEV_SCATTER) return(EIO);
if (iov->iov_size < SECTOR_SIZE + sizeof(fmt_param))
return(EINVAL);
if ((s=sys_datacopy(proc_nr, iov->iov_addr + SECTOR_SIZE,
SELF, (vir_bytes) &fmt_param,
(phys_bytes) sizeof(fmt_param))) != OK)
panic("FLOPPY", "Sys_vircopy failed", s);
/* Check that the number of sectors in the data is reasonable,
* to avoid division by 0. Leave checking of other data to
* the FDC.
*/
if (fmt_param.sectors_per_cylinder == 0) return(EIO);
/* Only the first sector of the parameters now needed. */
iov->iov_size = nbytes = SECTOR_SIZE;
}
/* Only try one sector if there were errors. */
if (errors > 0) nbytes = SECTOR_SIZE;
/* Compute cylinder and head of the track to access. */
fp->fl_cylinder = block / (NR_HEADS * f_sectors);
fp->fl_hardcyl = fp->fl_cylinder * f_dp->steps;
fp->fl_head = (block % (NR_HEADS * f_sectors)) / f_sectors;
/* For each sector on this track compute the user address it is to
* go or to come from.
*/
for (up = uaddrs; up < uaddrs + MAX_SECTORS; up++) *up = 0;
count = 0;
iop = iov;
sector = block % f_sectors;
for (;;) {
user_addr = iop->iov_addr;
chunk = iop->iov_size;
if ((chunk & SECTOR_MASK) != 0) return(EINVAL);
while (chunk > 0) {
uaddrs[sector++] = user_addr;
chunk -= SECTOR_SIZE;
user_addr += SECTOR_SIZE;
count += SECTOR_SIZE;
if (sector == f_sectors || count == nbytes)
goto track_set_up;
}
iop++;
}
track_set_up:
/* First check to see if a reset is needed. */
if (need_reset) f_reset();
/* See if motor is running; if not, turn it on and wait. */
start_motor();
/* Set the stepping rate and data rate */
if (f_dp != prev_dp) {
cmd[0] = FDC_SPECIFY;
cmd[1] = f_dp->spec1;
cmd[2] = SPEC2;
(void) fdc_command(cmd, 3);
if ((s=sys_outb(FDC_RATE, f_dp->rate)) != OK)
panic("FLOPPY","Sys_outb failed", s);
prev_dp = f_dp;
}
/* If we are going to a new cylinder, perform a seek. */
r = seek();
/* Avoid read_id() if we don't plan to read much. */
if (fp->fl_sector == NO_SECTOR && count < (6 * SECTOR_SIZE))
fp->fl_sector = 0;
for (nbytes = 0; nbytes < count; nbytes += SECTOR_SIZE) {
if (fp->fl_sector == NO_SECTOR) {
/* Find out what the current sector is. This often
* fails right after a seek, so try it twice.
*/
if (r == OK && read_id() != OK) r = read_id();
}
/* Look for the next job in uaddrs[] */
if (r == OK) {
for (;;) {
if (fp->fl_sector >= f_sectors)
fp->fl_sector = 0;
up = &uaddrs[fp->fl_sector];
if (*up != 0) break;
fp->fl_sector++;
}
}
if (r == OK && opcode == DEV_SCATTER) {
/* Copy the user bytes to the DMA buffer. */
if ((s=sys_datacopy(proc_nr, *up, SELF,
(vir_bytes) tmp_buf,
(phys_bytes) SECTOR_SIZE)) != OK)
panic("FLOPPY", "Sys_vircopy failed", s);
}
/* Set up the DMA chip and perform the transfer. */
if (r == OK) {
if (dma_setup(opcode) != OK) {
/* This can only fail for addresses above 16MB
* that cannot be handled by the controller,
* because it uses 24-bit addressing.
*/
return(EIO);
}
r = fdc_transfer(opcode);
}
if (r == OK && opcode == DEV_GATHER) {
/* Copy the DMA buffer to user space. */
if ((s=sys_datacopy(SELF, (vir_bytes) tmp_buf,
proc_nr, *up,
(phys_bytes) SECTOR_SIZE)) != OK)
panic("FLOPPY", "Sys_vircopy failed", s);
}
if (r != OK) {
/* Don't retry if write protected or too many errors. */
if (err_no_retry(r) || ++errors == MAX_ERRORS) {
return(EIO);
}
/* Recalibrate if halfway. */
if (errors == MAX_ERRORS / 2)
fp->fl_calibration = UNCALIBRATED;
nbytes = 0;
break; /* retry */
}
}
/* Book the bytes successfully transferred. */
position += nbytes;
for (;;) {
if (nbytes < iov->iov_size) {
/* Not done with this one yet. */
iov->iov_addr += nbytes;
iov->iov_size -= nbytes;
break;
}
nbytes -= iov->iov_size;
iov->iov_addr += iov->iov_size;
iov->iov_size = 0;
if (nbytes == 0) {
/* The rest is optional, so we return to give FS a
* chance to think it over.
*/
return(OK);
}
iov++;
nr_req--;
}
}
return(OK);
}
/*===========================================================================*
* dma_setup *
*===========================================================================*/
PRIVATE int dma_setup(opcode)
int opcode; /* DEV_GATHER or DEV_SCATTER */
{
/* The IBM PC can perform DMA operations by using the DMA chip. To use it,
* the DMA (Direct Memory Access) chip is loaded with the 20-bit memory address
* to be read from or written to, the byte count minus 1, and a read or write
* opcode. This routine sets up the DMA chip. Note that the chip is not
* capable of doing a DMA across a 64K boundary (e.g., you can't read a
* 512-byte block starting at physical address 65520).
*
* Warning! Also note that it's not possible to do DMA above 16 MB because
* the ISA bus uses 24-bit addresses. Addresses above 16 MB therefore will
* be interpreted modulo 16 MB, dangerously overwriting arbitrary memory.
* A check here denies the I/O if the address is out of range.
*/
pvb_pair_t byte_out[9];
int s;
/* First check the DMA memory address not to exceed maximum. */
if (tmp_phys != (tmp_phys & DMA_ADDR_MASK)) {
report("FLOPPY", "DMA denied because address out of range", NO_NUM);
return(EIO);
}
/* Set up the DMA registers. (The comment on the reset is a bit strong,
* it probably only resets the floppy channel.)
*/
pv_set(byte_out[0], DMA_INIT, DMA_RESET_VAL); /* reset the dma controller */
pv_set(byte_out[1], DMA_FLIPFLOP, 0); /* write anything to reset it */
pv_set(byte_out[2], DMA_MODE, opcode == DEV_SCATTER ? DMA_WRITE : DMA_READ);
pv_set(byte_out[3], DMA_ADDR, (unsigned) tmp_phys >> 0);
pv_set(byte_out[4], DMA_ADDR, (unsigned) tmp_phys >> 8);
pv_set(byte_out[5], DMA_TOP, (unsigned) (tmp_phys >> 16));
pv_set(byte_out[6], DMA_COUNT, (((SECTOR_SIZE - 1) >> 0) & 0xff));
pv_set(byte_out[7], DMA_COUNT, (SECTOR_SIZE - 1) >> 8);
pv_set(byte_out[8], DMA_INIT, 2); /* some sort of enable */
if ((s=sys_voutb(byte_out, 9)) != OK)
panic("FLOPPY","Sys_voutb in dma_setup() failed", s);
return(OK);
}
/*===========================================================================*
* start_motor *
*===========================================================================*/
PRIVATE void start_motor()
{
/* Control of the floppy disk motors is a big pain. If a motor is off, you
* have to turn it on first, which takes 1/2 second. You can't leave it on
* all the time, since that would wear out the diskette. However, if you turn
* the motor off after each operation, the system performance will be awful.
* The compromise used here is to leave it on for a few seconds after each
* operation. If a new operation is started in that interval, it need not be
* turned on again. If no new operation is started, a timer goes off and the
* motor is turned off. I/O port DOR has bits to control each of 4 drives.
*/
int s, motor_bit, running;
message mess;
motor_bit = 1 << f_drive; /* bit mask for this drive */
running = motor_status & motor_bit; /* nonzero if this motor is running */
motor_status |= motor_bit; /* want this drive running too */
if ((s=sys_outb(DOR,
(motor_status << MOTOR_SHIFT) | ENABLE_INT | f_drive)) != OK)
panic("FLOPPY","Sys_outb in start_motor() failed", s);
/* If the motor was already running, we don't have to wait for it. */
if (running) return; /* motor was already running */
/* Set an alarm timer to force a timeout if the hardware does not interrupt
* in time. Expect HARD_INT message, but check for SYN_ALARM timeout.
*/
f_set_timer(&f_tmr_timeout, f_dp->start, f_timeout);
f_busy = BSY_IO;
do {
receive(ANY, &mess);
if (mess.m_type == SYN_ALARM) {
f_expire_tmrs(NULL, NULL);
} else if(mess.m_type == DEV_PING) {
notify(mess.m_source);
} else {
f_busy = BSY_IDLE;
}
} while (f_busy == BSY_IO);
f_fp->fl_sector = NO_SECTOR;
}
/*===========================================================================*
* stop_motor *
*===========================================================================*/
PRIVATE void stop_motor(tp)
timer_t *tp;
{
/* This routine is called from an alarm timer after several seconds have
* elapsed with no floppy disk activity. It turns the drive motor off.
*/
int s;
motor_status &= ~(1 << tmr_arg(tp)->ta_int);
if ((s=sys_outb(DOR, (motor_status << MOTOR_SHIFT) | ENABLE_INT)) != OK)
panic("FLOPPY","Sys_outb in stop_motor() failed", s);
}
/*===========================================================================*
* floppy_stop *
*===========================================================================*/
PRIVATE void floppy_stop(struct driver *dp, message *m_ptr)
{
/* Stop all activity and cleanly exit with the system. */
int s;
sigset_t sigset = m_ptr->NOTIFY_ARG;
if (sigismember(&sigset, SIGTERM) || sigismember(&sigset, SIGKSTOP)) {
if ((s=sys_outb(DOR, ENABLE_INT)) != OK)
panic("FLOPPY","Sys_outb in floppy_stop() failed", s);
exit(0);
}
}
/*===========================================================================*
* seek *
*===========================================================================*/
PRIVATE int seek()
{
/* Issue a SEEK command on the indicated drive unless the arm is already
* positioned on the correct cylinder.
*/
struct floppy *fp = f_fp;
int r;
message mess;
u8_t cmd[3];
/* Are we already on the correct cylinder? */
if (fp->fl_calibration == UNCALIBRATED)
if (recalibrate() != OK) return(ERR_SEEK);
if (fp->fl_curcyl == fp->fl_hardcyl) return(OK);
/* No. Wrong cylinder. Issue a SEEK and wait for interrupt. */
cmd[0] = FDC_SEEK;
cmd[1] = (fp->fl_head << 2) | f_drive;
cmd[2] = fp->fl_hardcyl;
if (fdc_command(cmd, 3) != OK) return(ERR_SEEK);
if (f_intr_wait() != OK) return(ERR_TIMEOUT);
/* Interrupt has been received. Check drive status. */
fdc_out(FDC_SENSE); /* probe FDC to make it return status */
r = fdc_results(); /* get controller status bytes */
if (r != OK || (f_results[ST0] & ST0_BITS_SEEK) != SEEK_ST0
|| f_results[ST1] != fp->fl_hardcyl) {
/* seek failed, may need a recalibrate */
return(ERR_SEEK);
}
/* Give head time to settle on a format, no retrying here! */
if (f_device & FORMAT_DEV_BIT) {
/* Set a synchronous alarm to force a timeout if the hardware does
* not interrupt. Expect HARD_INT, but check for SYN_ALARM timeout.
*/
f_set_timer(&f_tmr_timeout, HZ/30, f_timeout);
f_busy = BSY_IO;
do {
receive(ANY, &mess);
if (mess.m_type == SYN_ALARM) {
f_expire_tmrs(NULL, NULL);
} else if(mess.m_type == DEV_PING) {
notify(mess.m_source);
} else {
f_busy = BSY_IDLE;
}
} while (f_busy == BSY_IO);
}
fp->fl_curcyl = fp->fl_hardcyl;
fp->fl_sector = NO_SECTOR;
return(OK);
}
/*===========================================================================*
* fdc_transfer *
*===========================================================================*/
PRIVATE int fdc_transfer(opcode)
int opcode; /* DEV_GATHER or DEV_SCATTER */
{
/* The drive is now on the proper cylinder. Read, write or format 1 block. */
struct floppy *fp = f_fp;
int r, s;
u8_t cmd[9];
/* Never attempt a transfer if the drive is uncalibrated or motor is off. */
if (fp->fl_calibration == UNCALIBRATED) return(ERR_TRANSFER);
if ((motor_status & (1 << f_drive)) == 0) return(ERR_TRANSFER);
/* The command is issued by outputting several bytes to the controller chip.
*/
if (f_device & FORMAT_DEV_BIT) {
cmd[0] = FDC_FORMAT;
cmd[1] = (fp->fl_head << 2) | f_drive;
cmd[2] = fmt_param.sector_size_code;
cmd[3] = fmt_param.sectors_per_cylinder;
cmd[4] = fmt_param.gap_length_for_format;
cmd[5] = fmt_param.fill_byte_for_format;
if (fdc_command(cmd, 6) != OK) return(ERR_TRANSFER);
} else {
cmd[0] = opcode == DEV_SCATTER ? FDC_WRITE : FDC_READ;
cmd[1] = (fp->fl_head << 2) | f_drive;
cmd[2] = fp->fl_cylinder;
cmd[3] = fp->fl_head;
cmd[4] = BASE_SECTOR + fp->fl_sector;
cmd[5] = SECTOR_SIZE_CODE;
cmd[6] = f_sectors;
cmd[7] = f_dp->gap; /* sector gap */
cmd[8] = DTL; /* data length */
if (fdc_command(cmd, 9) != OK) return(ERR_TRANSFER);
}
/* Block, waiting for disk interrupt. */
if (f_intr_wait() != OK) {
printf("%s: disk interrupt timed out.\n", f_name());
return(ERR_TIMEOUT);
}
/* Get controller status and check for errors. */
r = fdc_results();
if (r != OK) return(r);
if (f_results[ST1] & WRITE_PROTECT) {
printf("%s: diskette is write protected.\n", f_name());
return(ERR_WR_PROTECT);
}
if ((f_results[ST0] & ST0_BITS_TRANS) != TRANS_ST0) return(ERR_TRANSFER);
if (f_results[ST1] | f_results[ST2]) return(ERR_TRANSFER);
if (f_device & FORMAT_DEV_BIT) return(OK);
/* Compare actual numbers of sectors transferred with expected number. */
s = (f_results[ST_CYL] - fp->fl_cylinder) * NR_HEADS * f_sectors;
s += (f_results[ST_HEAD] - fp->fl_head) * f_sectors;
s += (f_results[ST_SEC] - BASE_SECTOR - fp->fl_sector);
if (s != 1) return(ERR_TRANSFER);
/* This sector is next for I/O: */
fp->fl_sector = f_results[ST_SEC] - BASE_SECTOR;
#if 0
if (processor < 386) fp->fl_sector++; /* Old CPU can't keep up. */
#endif
return(OK);
}
/*===========================================================================*
* fdc_results *
*===========================================================================*/
PRIVATE int fdc_results()
{
/* Extract results from the controller after an operation, then allow floppy
* interrupts again.
*/
int s, result_nr;
unsigned long status;
clock_t t0,t1;
/* Extract bytes from FDC until it says it has no more. The loop is
* really an outer loop on result_nr and an inner loop on status.
* A timeout flag alarm is set.
*/
result_nr = 0;
getuptime(&t0);
do {
/* Reading one byte is almost a mirror of fdc_out() - the DIRECTION
* bit must be set instead of clear, but the CTL_BUSY bit destroys
* the perfection of the mirror.
*/
if ((s=sys_inb(FDC_STATUS, &status)) != OK)
panic("FLOPPY","Sys_inb in fdc_results() failed", s);
status &= (MASTER | DIRECTION | CTL_BUSY);
if (status == (MASTER | DIRECTION | CTL_BUSY)) {
unsigned long tmp_r;
if (result_nr >= MAX_RESULTS) break; /* too many results */
if ((s=sys_inb(FDC_DATA, &tmp_r)) != OK)
panic("FLOPPY","Sys_inb in fdc_results() failed", s);
f_results[result_nr] = tmp_r;
result_nr ++;
continue;
}
if (status == MASTER) { /* all read */
if ((s=sys_irqenable(&irq_hook_id)) != OK)
panic("FLOPPY", "Couldn't enable IRQs", s);
return(OK); /* only good exit */
}
} while ( (s=getuptime(&t1))==OK && (t1-t0) < TIMEOUT_TICKS );
if (OK!=s) printf("FLOPPY: warning, getuptime failed: %d\n", s);
need_reset = TRUE; /* controller chip must be reset */
if ((s=sys_irqenable(&irq_hook_id)) != OK)
panic("FLOPPY", "Couldn't enable IRQs", s);
return(ERR_STATUS);
}
/*===========================================================================*
* fdc_command *
*===========================================================================*/
PRIVATE int fdc_command(cmd, len)
u8_t *cmd; /* command bytes */
int len; /* command length */
{
/* Output a command to the controller. */
/* Set a synchronous alarm to force a timeout if the hardware does
* not interrupt. Expect HARD_INT, but check for SYN_ALARM timeout.
* Note that the actual check is done by the code that issued the
* fdc_command() call.
*/
f_set_timer(&f_tmr_timeout, WAKEUP, f_timeout);
f_busy = BSY_IO;
while (len > 0) {
fdc_out(*cmd++);
len--;
}
return(need_reset ? ERR_DRIVE : OK);
}
/*===========================================================================*
* fdc_out *
*===========================================================================*/
PRIVATE void fdc_out(val)
int val; /* write this byte to floppy disk controller */
{
/* Output a byte to the controller. This is not entirely trivial, since you
* can only write to it when it is listening, and it decides when to listen.
* If the controller refuses to listen, the FDC chip is given a hard reset.
*/
clock_t t0, t1;
int s;
unsigned long status;
if (need_reset) return; /* if controller is not listening, return */
/* It may take several tries to get the FDC to accept a command. */
getuptime(&t0);
do {
if ( (s=getuptime(&t1))==OK && (t1-t0) > TIMEOUT_TICKS ) {
if (OK!=s) printf("FLOPPY: warning, getuptime failed: %d\n", s);
need_reset = TRUE; /* hit it over the head */
return;
}
if ((s=sys_inb(FDC_STATUS, &status)) != OK)
panic("FLOPPY","Sys_inb in fdc_out() failed", s);
}
while ((status & (MASTER | DIRECTION)) != (MASTER | 0));
if ((s=sys_outb(FDC_DATA, val)) != OK)
panic("FLOPPY","Sys_outb in fdc_out() failed", s);
}
/*===========================================================================*
* recalibrate *
*===========================================================================*/
PRIVATE int recalibrate()
{
/* The floppy disk controller has no way of determining its absolute arm
* position (cylinder). Instead, it steps the arm a cylinder at a time and
* keeps track of where it thinks it is (in software). However, after a
* SEEK, the hardware reads information from the diskette telling where the
* arm actually is. If the arm is in the wrong place, a recalibration is done,
* which forces the arm to cylinder 0. This way the controller can get back
* into sync with reality.
*/
struct floppy *fp = f_fp;
int r;
u8_t cmd[2];
/* Issue the RECALIBRATE command and wait for the interrupt. */
cmd[0] = FDC_RECALIBRATE; /* tell drive to recalibrate itself */
cmd[1] = f_drive; /* specify drive */
if (fdc_command(cmd, 2) != OK) return(ERR_SEEK);
if (f_intr_wait() != OK) return(ERR_TIMEOUT);
/* Determine if the recalibration succeeded. */
fdc_out(FDC_SENSE); /* issue SENSE command to request results */
r = fdc_results(); /* get results of the FDC_RECALIBRATE command*/
fp->fl_curcyl = NO_CYL; /* force a SEEK next time */
fp->fl_sector = NO_SECTOR;
if (r != OK || /* controller would not respond */
(f_results[ST0] & ST0_BITS_SEEK) != SEEK_ST0 || f_results[ST_PCN] != 0) {
/* Recalibration failed. FDC must be reset. */
need_reset = TRUE;
return(ERR_RECALIBRATE);
} else {
/* Recalibration succeeded. */
fp->fl_calibration = CALIBRATED;
fp->fl_curcyl = f_results[ST_PCN];
return(OK);
}
}
/*===========================================================================*
* f_reset *
*===========================================================================*/
PRIVATE void f_reset()
{
/* Issue a reset to the controller. This is done after any catastrophe,
* like the controller refusing to respond.
*/
pvb_pair_t byte_out[2];
int s,i;
message mess;
/* Disable interrupts and strobe reset bit low. */
need_reset = FALSE;
/* It is not clear why the next lock is needed. Writing 0 to DOR causes
* interrupt, while the PC documentation says turning bit 8 off disables
* interrupts. Without the lock:
* 1) the interrupt handler sets the floppy mask bit in the 8259.
* 2) writing ENABLE_INT to DOR causes the FDC to assert the interrupt
* line again, but the mask stops the cpu being interrupted.
* 3) the sense interrupt clears the interrupt (not clear which one).
* and for some reason the reset does not work.
*/
(void) fdc_command((u8_t *) 0, 0); /* need only the timer */
motor_status = 0;
pv_set(byte_out[0], DOR, 0); /* strobe reset bit low */
pv_set(byte_out[1], DOR, ENABLE_INT); /* strobe it high again */
if ((s=sys_voutb(byte_out, 2)) != OK)
panic("FLOPPY", "Sys_voutb in f_reset() failed", s);
/* A synchronous alarm timer was set in fdc_command. Expect a HARD_INT
* message to collect the reset interrupt, but be prepared to handle the
* SYN_ALARM message on a timeout.
*/
do {
receive(ANY, &mess);
if (mess.m_type == SYN_ALARM) {
f_expire_tmrs(NULL, NULL);
} else if(mess.m_type == DEV_PING) {
notify(mess.m_source);
} else { /* expect HARD_INT */
f_busy = BSY_IDLE;
}
} while (f_busy == BSY_IO);
/* The controller supports 4 drives and returns a result for each of them.
* Collect all the results now. The old version only collected the first
* result. This happens to work for 2 drives, but it doesn't work for 3
* or more drives, at least with only drives 0 and 2 actually connected
* (the controller generates an extra interrupt for the middle drive when
* drive 2 is accessed and the driver panics).
*
* It would be better to keep collecting results until there are no more.
* For this, fdc_results needs to return the number of results (instead
* of OK) when it succeeds.
*/
for (i = 0; i < 4; i++) {
fdc_out(FDC_SENSE); /* probe FDC to make it return status */
(void) fdc_results(); /* flush controller */
}
for (i = 0; i < NR_DRIVES; i++) /* clear each drive */
floppy[i].fl_calibration = UNCALIBRATED;
/* The current timing parameters must be specified again. */
prev_dp = NULL;
}
/*===========================================================================*
* f_intr_wait *
*===========================================================================*/
PRIVATE int f_intr_wait()
{
/* Wait for an interrupt, but not forever. The FDC may have all the time of
* the world, but we humans do not.
*/
message mess;
/* We expect a HARD_INT message from the interrupt handler, but if there is
* a timeout, a SYN_ALARM notification is received instead. If a timeout
* occurs, report an error.
*/
do {
receive(ANY, &mess);
if (mess.m_type == SYN_ALARM) {
f_expire_tmrs(NULL, NULL);
} else if(mess.m_type == DEV_PING) {
notify(mess.m_source);
} else {
f_busy = BSY_IDLE;
}
} while (f_busy == BSY_IO);
if (f_busy == BSY_WAKEN) {
/* No interrupt from the FDC, this means that there is probably no
* floppy in the drive. Get the FDC down to earth and return error.
*/
need_reset = TRUE;
return(ERR_TIMEOUT);
}
return(OK);
}
/*===========================================================================*
* f_timeout *
*===========================================================================*/
PRIVATE void f_timeout(tp)
timer_t *tp;
{
/* This routine is called when a timer expires. Usually to tell that a
* motor has spun up, but also to forge an interrupt when it takes too long
* for the FDC to interrupt (no floppy in the drive). It sets a flag to tell
* what has happened.
*/
if (f_busy == BSY_IO) {
f_busy = BSY_WAKEN;
}
}
/*===========================================================================*
* read_id *
*===========================================================================*/
PRIVATE int read_id()
{
/* Determine current cylinder and sector. */
struct floppy *fp = f_fp;
int result;
u8_t cmd[2];
/* Never attempt a read id if the drive is uncalibrated or motor is off. */
if (fp->fl_calibration == UNCALIBRATED) return(ERR_READ_ID);
if ((motor_status & (1 << f_drive)) == 0) return(ERR_READ_ID);
/* The command is issued by outputting 2 bytes to the controller chip. */
cmd[0] = FDC_READ_ID; /* issue the read id command */
cmd[1] = (fp->fl_head << 2) | f_drive;
if (fdc_command(cmd, 2) != OK) return(ERR_READ_ID);
if (f_intr_wait() != OK) return(ERR_TIMEOUT);
/* Get controller status and check for errors. */
result = fdc_results();
if (result != OK) return(result);
if ((f_results[ST0] & ST0_BITS_TRANS) != TRANS_ST0) return(ERR_READ_ID);
if (f_results[ST1] | f_results[ST2]) return(ERR_READ_ID);
/* The next sector is next for I/O: */
fp->fl_sector = f_results[ST_SEC] - BASE_SECTOR + 1;
return(OK);
}
/*===========================================================================*
* f_do_open *
*===========================================================================*/
PRIVATE int f_do_open(dp, m_ptr)
struct driver *dp;
message *m_ptr; /* pointer to open message */
{
/* Handle an open on a floppy. Determine diskette type if need be. */
int dtype;
struct test_order *top;
/* Decode the message parameters. */
if (f_prepare(m_ptr->DEVICE) == NIL_DEV) return(ENXIO);
dtype = f_device & DEV_TYPE_BITS; /* get density from minor dev */
if (dtype >= MINOR_fd0p0) dtype = 0;
if (dtype != 0) {
/* All types except 0 indicate a specific drive/medium combination.*/
dtype = (dtype >> DEV_TYPE_SHIFT) - 1;
if (dtype >= NT) return(ENXIO);
f_fp->fl_density = dtype;
(void) f_prepare(f_device); /* Recompute parameters. */
return(OK);
}
if (f_device & FORMAT_DEV_BIT) return(EIO); /* Can't format /dev/fdN */
/* The device opened is /dev/fdN. Experimentally determine drive/medium.
* First check fl_density. If it is not NO_DENS, the drive has been used
* before and the value of fl_density tells what was found last time. Try
* that first. If the motor is still running then assume nothing changed.
*/
if (f_fp->fl_density != NO_DENS) {
if (motor_status & (1 << f_drive)) return(OK);
if (test_read(f_fp->fl_density) == OK) return(OK);
}
/* Either drive type is unknown or a different diskette is now present.
* Use test_order to try them one by one.
*/
for (top = &test_order[0]; top < &test_order[NT-1]; top++) {
dtype = top->t_density;
/* Skip densities that have been proven to be impossible */
if (!(f_fp->fl_class & (1 << dtype))) continue;
if (test_read(dtype) == OK) {
/* The test succeeded, use this knowledge to limit the
* drive class to match the density just read.
*/
f_fp->fl_class &= top->t_class;
return(OK);
}
/* Test failed, wrong density or did it time out? */
if (f_busy == BSY_WAKEN) break;
}
f_fp->fl_density = NO_DENS;
return(EIO); /* nothing worked */
}
/*===========================================================================*
* test_read *
*===========================================================================*/
PRIVATE int test_read(density)
int density;
{
/* Try to read the highest numbered sector on cylinder 2. Not all floppy
* types have as many sectors per track, and trying cylinder 2 finds the
* ones that need double stepping.
*/
int device;
off_t position;
iovec_t iovec1;
int result;
f_fp->fl_density = density;
device = ((density + 1) << DEV_TYPE_SHIFT) + f_drive;
(void) f_prepare(device);
position = (off_t) f_dp->test << SECTOR_SHIFT;
iovec1.iov_addr = (vir_bytes) tmp_buf;
iovec1.iov_size = SECTOR_SIZE;
result = f_transfer(SELF, DEV_GATHER, position, &iovec1, 1);
if (iovec1.iov_size != 0) return(EIO);
partition(&f_dtab, f_drive, P_FLOPPY, 0);
return(OK);
}
/*===========================================================================*
* f_geometry *
*===========================================================================*/
PRIVATE void f_geometry(entry)
struct partition *entry;
{
entry->cylinders = f_dp->cyls;
entry->heads = NR_HEADS;
entry->sectors = f_sectors;
}
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