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minix/drivers/floppy/floppy.c
David van Moolenbroek b4d909d415 Split block/character protocols and libdriver 
This patch separates the character and block driver communication
protocols. The old character protocol remains the same, but a new
block protocol is introduced. The libdriver library is replaced by
two new libraries: libchardriver and libblockdriver. Their exposed
API, and drivers that use them, have been updated accordingly.
Together, libbdev and libblockdriver now completely abstract away
the message format used by the block protocol. As the memory driver
is both a character and a block device driver, it now implements its
own message loop.

The most important semantic change made to the block protocol is that
it is no longer possible to return both partial results and an error
for a single transfer. This simplifies the interaction between the
caller and the driver, as the I/O vector no longer needs to be copied
back. Also, drivers are now no longer supposed to decide based on the
layout of the I/O vector when a transfer should be cut short. Put
simply, transfers are now supposed to either succeed completely, or
result in an error.

After this patch, the state of the various pieces is as follows:
- block protocol: stable
- libbdev API: stable for synchronous communication
- libblockdriver API: needs slight revision (the drvlib/partition API
  in particular; the threading API will also change shortly)
- character protocol: needs cleanup
- libchardriver API: needs cleanup accordingly
- driver restarts: largely unsupported until endpoint changes are
  reintroduced

As a side effect, this patch eliminates several bugs, hacks, and gcc
-Wall and -W warnings all over the place. It probably introduces a
few new ones, too.

Update warning: this patch changes the protocol between MFS and disk
drivers, so in order to use old/new images, the MFS from the ramdisk
must be used to mount all file systems.
2011-11-23 14:06:37 +01:00

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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 <machine/diskparm.h>
#include <minix/sysutil.h>
#include <minix/syslib.h>
#include <minix/endpoint.h>
#include <stdio.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*system_hz) /* how long to wait before stopping motor */
#define WAKEUP (2*system_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 5000000L /* microseconds 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 ((unsigned) -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) */
clock_t start_ms; /* motor start (milliseconds) */
u8_t gap; /* gap size */
u8_t spec1; /* first specify byte (SRT/HUT) */
} fdensity[NT] = {
{ 9, 40, 1, 4*9, 2, 500, 0x2A, 0xDF }, /* 360K / 360K */
{ 15, 80, 1, 14, 0, 500, 0x1B, 0xDF }, /* 1.2M / 1.2M */
{ 9, 40, 2, 2*9, 2, 500, 0x2A, 0xDF }, /* 360K / 720K */
{ 9, 80, 1, 4*9, 2, 750, 0x2A, 0xDF }, /* 720K / 720K */
{ 9, 40, 2, 2*9, 1, 500, 0x23, 0xDF }, /* 360K / 1.2M */
{ 9, 80, 1, 4*9, 1, 500, 0x23, 0xDF }, /* 720K / 1.2M */
{ 18, 80, 1, 17, 0, 750, 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 */
PUBLIC int motor_status; /* bitmap of current motor status */
PRIVATE int need_reset; /* set to 1 when controller must be reset */
PUBLIC 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) */
PUBLIC 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 u32_t system_hz; /* system clock frequency */
FORWARD _PROTOTYPE( void f_expire_tmrs, (clock_t stamp) );
FORWARD _PROTOTYPE( void stop_motor, (timer_t *tp) );
FORWARD _PROTOTYPE( void f_timeout, (timer_t *tp) );
FORWARD _PROTOTYPE( struct device *f_prepare, (dev_t device) );
FORWARD _PROTOTYPE( struct device *f_part, (dev_t minor) );
FORWARD _PROTOTYPE( void f_cleanup, (void) );
FORWARD _PROTOTYPE( ssize_t f_transfer, (dev_t minor, int do_write,
u64_t position, endpoint_t proc_nr, iovec_t *iov,
unsigned int nr_req, int flags) );
FORWARD _PROTOTYPE( int dma_setup, (int do_write) );
FORWARD _PROTOTYPE( void start_motor, (void) );
FORWARD _PROTOTYPE( int seek, (void) );
FORWARD _PROTOTYPE( int fdc_transfer, (int do_write) );
FORWARD _PROTOTYPE( int fdc_results, (void) );
FORWARD _PROTOTYPE( int fdc_command, (const 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, (dev_t minor, int access) );
FORWARD _PROTOTYPE( int f_do_close, (dev_t minor) );
FORWARD _PROTOTYPE( int test_read, (int density) );
FORWARD _PROTOTYPE( void f_geometry, (dev_t minor,
struct partition *entry) );
/* Entry points to this driver. */
PRIVATE struct blockdriver f_dtab = {
f_do_open, /* open or mount request, sense type of diskette */
f_do_close, /* nothing on a close */
f_transfer, /* do the I/O */
NULL, /* no other I/O control requests are supported */
f_cleanup, /* cleanup before sending reply to user process */
f_part, /* return partition information structure */
f_geometry, /* tell the geometry of the diskette */
NULL, /* no processing of hardware interrupts */
f_expire_tmrs,/* expire all alarm timers */
NULL, /* no processing of other messages */
NULL /* no threading support */
};
static char *floppy_buf;
static phys_bytes floppy_buf_phys;
/* SEF functions and variables. */
FORWARD _PROTOTYPE( void sef_local_startup, (void) );
FORWARD _PROTOTYPE( int sef_cb_init_fresh, (int type, sef_init_info_t *info) );
FORWARD _PROTOTYPE( void sef_cb_signal_handler, (int signo) );
EXTERN _PROTOTYPE( int sef_cb_lu_prepare, (int state) );
EXTERN _PROTOTYPE( int sef_cb_lu_state_isvalid, (int state) );
EXTERN _PROTOTYPE( void sef_cb_lu_state_dump, (int state) );
PUBLIC int last_was_write;
/*===========================================================================*
* floppy_task *
*===========================================================================*/
PUBLIC int main(void)
{
/* SEF local startup. */
sef_local_startup();
/* Call the generic receive loop. */
blockdriver_task(&f_dtab);
return(OK);
}
/*===========================================================================*
* sef_local_startup *
*===========================================================================*/
PRIVATE void sef_local_startup(void)
{
/* Register init callbacks. */
sef_setcb_init_fresh(sef_cb_init_fresh);
sef_setcb_init_lu(sef_cb_init_fresh);
sef_setcb_init_restart(sef_cb_init_fresh);
/* Register live update callbacks. */
sef_setcb_lu_prepare(sef_cb_lu_prepare);
sef_setcb_lu_state_isvalid(sef_cb_lu_state_isvalid);
sef_setcb_lu_state_dump(sef_cb_lu_state_dump);
/* Register signal callbacks. */
sef_setcb_signal_handler(sef_cb_signal_handler);
/* Let SEF perform startup. */
sef_startup();
}
/*===========================================================================*
* sef_cb_init_fresh *
*===========================================================================*/
PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
{
/* Initialize the floppy driver. */
struct floppy *fp;
int s;
/* Initialize the floppy structure and the timers. */
system_hz = sys_hz();
if(!(floppy_buf = alloc_contig(2*DMA_BUF_SIZE,
AC_LOWER16M | AC_ALIGN4K, &floppy_buf_phys)))
panic("couldn't allocate dma buffer");
init_timer(&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;
init_timer(&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("Couldn't set IRQ policy: %d", s);
if ((s=sys_irqenable(&irq_hook_id)) != OK)
panic("Couldn't enable IRQs: %d", s);
/* Announce we are up! */
blockdriver_announce();
return(OK);
}
/*===========================================================================*
* sef_cb_signal_handler *
*===========================================================================*/
PRIVATE void sef_cb_signal_handler(int signo)
{
int s;
/* Only check for termination signal, ignore anything else. */
if (signo != SIGTERM) return;
/* Stop all activity and cleanly exit with the system. */
if ((s=sys_outb(DOR, ENABLE_INT)) != OK)
panic("Sys_outb failed: %d", s);
exit(0);
}
/*===========================================================================*
* f_expire_tmrs *
*===========================================================================*/
PRIVATE void f_expire_tmrs(clock_t stamp)
{
/* A synchronous alarm message was received. Call the watchdog function for
* each expired timer, if any.
*/
expire_timers(stamp);
}
/*===========================================================================*
* f_prepare *
*===========================================================================*/
PRIVATE struct device *f_prepare(dev_t device)
{
/* Prepare for I/O on a device. */
f_device = device;
f_drive = device & ~(DEV_TYPE_BITS | FORMAT_DEV_BIT);
if (f_drive >= NR_DRIVES) return(NULL);
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_part *
*===========================================================================*/
PRIVATE struct device *f_part(dev_t minor)
{
/* Return a pointer to the partition information of the given minor device. */
return f_prepare(minor);
}
/*===========================================================================*
* f_cleanup *
*===========================================================================*/
PRIVATE void f_cleanup(void)
{
/* Start a timer to turn the motor off in a few seconds. */
set_timer(&f_fp->fl_tmr_stop, MOTOR_OFF, stop_motor, f_drive);
/* Exiting the floppy driver, so forget where we are. */
f_fp->fl_sector = NO_SECTOR;
}
/*===========================================================================*
* f_transfer *
*===========================================================================*/
PRIVATE ssize_t f_transfer(
dev_t minor, /* minor device number */
int do_write, /* read or write? */
u64_t pos64, /* offset on device to read or write */
endpoint_t proc_nr, /* process doing the request */
iovec_t *iov, /* pointer to read or write request vector */
unsigned int nr_req, /* length of request vector */
int UNUSED(flags) /* transfer flags */
)
{
#define NO_OFFSET -1
struct floppy *fp;
iovec_t *iop, *iov_end = iov + nr_req;
int s, r, errors, nr;
unsigned block, nbytes, count, chunk, sector;
unsigned long dv_size;
vir_bytes user_offset, iov_offset = 0, iop_offset;
unsigned long position;
signed long uoffsets[MAX_SECTORS], *up;
cp_grant_id_t ugrants[MAX_SECTORS], *ug = NULL;
u8_t cmd[3];
ssize_t total;
if (f_prepare(minor) == NULL) return(ENXIO);
fp = f_fp;
dv_size = cv64ul(f_dv->dv_size);
if (ex64hi(pos64) != 0)
return OK; /* Way beyond EOF */
position= cv64ul(pos64);
total = 0;
/* Record the direction of the last transfer performed. */
last_was_write = do_write;
/* 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(total); /* 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 (!do_write) return(EIO);
if (iov->iov_size < SECTOR_SIZE + sizeof(fmt_param))
return(EINVAL);
if(proc_nr != SELF) {
s=sys_safecopyfrom(proc_nr, iov->iov_addr,
SECTOR_SIZE + iov_offset, (vir_bytes) &fmt_param,
(phys_bytes) sizeof(fmt_param), D);
if(s != OK)
panic("sys_safecopyfrom failed: %d", s);
} else {
memcpy(&fmt_param, (void *) (iov->iov_addr +
SECTOR_SIZE + iov_offset),
(phys_bytes) sizeof(fmt_param));
}
/* 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 = uoffsets; up < uoffsets + MAX_SECTORS; up++) *up = NO_OFFSET;
count = 0;
iop = iov;
sector = block % f_sectors;
nr = 0;
iop_offset = iov_offset;
for (;;) {
nr++;
user_offset = iop_offset;
chunk = iop->iov_size;
if ((chunk & SECTOR_MASK) != 0) return(EINVAL);
while (chunk > 0) {
ugrants[sector] = iop->iov_addr;
uoffsets[sector++] = user_offset;
chunk -= SECTOR_SIZE;
user_offset += SECTOR_SIZE;
count += SECTOR_SIZE;
if (sector == f_sectors || count == nbytes)
goto track_set_up;
}
iop_offset = 0;
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("Sys_outb failed: %d", 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 uoffsets[] */
if (r == OK) {
for (;;) {
if (fp->fl_sector >= f_sectors)
fp->fl_sector = 0;
up = &uoffsets[fp->fl_sector];
ug = &ugrants[fp->fl_sector];
if (*up != NO_OFFSET) break;
fp->fl_sector++;
}
if (do_write) {
/* Copy the user bytes to the DMA buffer. */
if(proc_nr != SELF) {
s=sys_safecopyfrom(proc_nr, *ug, *up,
(vir_bytes) floppy_buf,
(phys_bytes) SECTOR_SIZE, D);
if(s != OK)
panic("sys_safecopyfrom failed: %d", s);
} else {
memcpy(floppy_buf, (void *) (*ug + *up), SECTOR_SIZE);
}
}
}
/* Set up the DMA chip and perform the transfer. */
if (r == OK) {
if (dma_setup(do_write) != 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(do_write);
}
if (r == OK && !do_write) {
/* Copy the DMA buffer to user space. */
if(proc_nr != SELF) {
s=sys_safecopyto(proc_nr, *ug, *up,
(vir_bytes) floppy_buf,
(phys_bytes) SECTOR_SIZE, D);
if(s != OK)
panic("sys_safecopyto failed: %d", s);
} else {
memcpy((void *) (*ug + *up), floppy_buf, SECTOR_SIZE);
}
}
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;
total += nbytes;
while (nbytes > 0) {
if (nbytes < iov->iov_size) {
/* Not done with this one yet. */
iov_offset += nbytes;
iov->iov_size -= nbytes;
break;
}
iov_offset = 0;
nbytes -= iov->iov_size;
iov->iov_size = 0;
iov++;
nr_req--;
}
}
return(total);
}
/*===========================================================================*
* dma_setup *
*===========================================================================*/
PRIVATE int dma_setup(int do_write)
{
/* 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 (floppy_buf_phys != (floppy_buf_phys & DMA_ADDR_MASK)) {
printf("floppy: DMA denied because address out of range\n");
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, do_write ? DMA_WRITE : DMA_READ);
pv_set(byte_out[3], DMA_ADDR, (unsigned) (floppy_buf_phys >> 0) & 0xff);
pv_set(byte_out[4], DMA_ADDR, (unsigned) (floppy_buf_phys >> 8) & 0xff);
pv_set(byte_out[5], DMA_TOP, (unsigned) (floppy_buf_phys >> 16) & 0xff);
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("Sys_voutb in dma_setup() failed: %d", s);
return(OK);
}
/*===========================================================================*
* start_motor *
*===========================================================================*/
PRIVATE void start_motor(void)
{
/* 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;
int ipc_status;
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("Sys_outb in start_motor() failed: %d", 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 an interrupt, but check for a timeout.
*/
set_timer(&f_tmr_timeout, f_dp->start_ms * system_hz / 1000, f_timeout, 0);
f_busy = BSY_IO;
do {
driver_receive(ANY, &mess, &ipc_status);
if (is_ipc_notify(ipc_status)) {
switch (_ENDPOINT_P(mess.m_source)) {
case CLOCK:
f_expire_tmrs(mess.NOTIFY_TIMESTAMP);
break;
default :
f_busy = BSY_IDLE;
break;
}
} else {
f_busy = BSY_IDLE;
}
} while (f_busy == BSY_IO);
f_fp->fl_sector = NO_SECTOR;
}
/*===========================================================================*
* stop_motor *
*===========================================================================*/
PRIVATE void stop_motor(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("Sys_outb in stop_motor() failed: %d", s);
}
/*===========================================================================*
* seek *
*===========================================================================*/
PRIVATE int seek(void)
{
/* 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;
int ipc_status;
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.
*/
set_timer(&f_tmr_timeout, system_hz/30, f_timeout, 0);
f_busy = BSY_IO;
do {
driver_receive(ANY, &mess, &ipc_status);
if (is_ipc_notify(ipc_status)) {
switch (_ENDPOINT_P(mess.m_source)) {
case CLOCK:
f_expire_tmrs(mess.NOTIFY_TIMESTAMP);
break;
default :
f_busy = BSY_IDLE;
break;
}
} 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(int do_write)
{
/* 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] = do_write ? 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("fd%u: disk interrupt timed out.\n", f_drive);
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("fd%u: diskette is write protected.\n", f_drive);
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(void)
{
/* Extract results from the controller after an operation, then allow floppy
* interrupts again.
*/
int s, result_nr;
unsigned long status;
spin_t spin;
/* 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;
SPIN_FOR(&spin, TIMEOUT_MICROS) {
/* 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("Sys_inb in fdc_results() failed: %d", 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("Sys_inb in fdc_results() failed: %d", s);
f_results[result_nr] = tmp_r;
result_nr ++;
continue;
}
if (status == MASTER) { /* all read */
if ((s=sys_irqenable(&irq_hook_id)) != OK)
panic("Couldn't enable IRQs: %d", s);
return(OK); /* only good exit */
}
}
need_reset = TRUE; /* controller chip must be reset */
if ((s=sys_irqenable(&irq_hook_id)) != OK)
panic("Couldn't enable IRQs: %d", s);
return(ERR_STATUS);
}
/*===========================================================================*
* fdc_command *
*===========================================================================*/
PRIVATE int fdc_command(
const 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.
* Note that the actual check is done by the code that issued the
* fdc_command() call.
*/
set_timer(&f_tmr_timeout, WAKEUP, f_timeout, 0);
f_busy = BSY_IO;
while (len > 0) {
fdc_out(*cmd++);
len--;
}
return(need_reset ? ERR_DRIVE : OK);
}
/*===========================================================================*
* fdc_out *
*===========================================================================*/
PRIVATE void fdc_out(
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.
*/
spin_t spin;
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. */
SPIN_FOR(&spin, TIMEOUT_MICROS) {
if ((s=sys_inb(FDC_STATUS, &status)) != OK)
panic("Sys_inb in fdc_out() failed: %d", s);
if ((status & (MASTER | DIRECTION)) == (MASTER | 0)) {
if ((s=sys_outb(FDC_DATA, val)) != OK)
panic("Sys_outb in fdc_out() failed: %d", s);
return;
}
}
need_reset = TRUE; /* hit it over the head */
}
/*===========================================================================*
* recalibrate *
*===========================================================================*/
PRIVATE int recalibrate(void)
{
/* 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(void)
{
/* 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;
int ipc_status;
/* 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("Sys_voutb in f_reset() failed: %d", s);
/* A synchronous alarm timer was set in fdc_command. Expect an interrupt,
* but be prepared to handle a timeout.
*/
do {
driver_receive(ANY, &mess, &ipc_status);
if (is_ipc_notify(ipc_status)) {
switch (_ENDPOINT_P(mess.m_source)) {
case CLOCK:
f_expire_tmrs(mess.NOTIFY_TIMESTAMP);
break;
default :
f_busy = BSY_IDLE;
break;
}
} else { /* expect hw interrupt */
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(void)
{
/* Wait for an interrupt, but not forever. The FDC may have all the time of
* the world, but we humans do not.
*/
message mess;
int ipc_status;
/* We expect an interrupt, but if a timeout, occurs, report an error. */
do {
driver_receive(ANY, &mess, &ipc_status);
if (is_ipc_notify(ipc_status)) {
switch (_ENDPOINT_P(mess.m_source)) {
case CLOCK:
f_expire_tmrs(mess.NOTIFY_TIMESTAMP);
break;
default :
f_busy = BSY_IDLE;
break;
}
} 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(timer_t *UNUSED(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(void)
{
/* 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(dev_t minor, int UNUSED(access))
{
/* 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(minor) == NULL) 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 */
}
/*===========================================================================*
* f_do_close *
*===========================================================================*/
PRIVATE int f_do_close(dev_t UNUSED(minor))
{
/* Handle a close on a floppy. Nothing to do here. */
return(OK);
}
/*===========================================================================*
* test_read *
*===========================================================================*/
PRIVATE int test_read(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;
ssize_t 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) floppy_buf;
iovec1.iov_size = SECTOR_SIZE;
result = f_transfer(device, FALSE /*do_write*/, cvul64(position), SELF,
&iovec1, 1, BDEV_NOFLAGS);
if (result != SECTOR_SIZE) return(EIO);
partition(&f_dtab, f_drive, P_FLOPPY, 0);
return(OK);
}
/*===========================================================================*
* f_geometry *
*===========================================================================*/
PRIVATE void f_geometry(dev_t minor, struct partition *entry)
{
if (f_prepare(minor) == NULL) return;
entry->cylinders = f_dp->cyls;
entry->heads = NR_HEADS;
entry->sectors = f_sectors;
}
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