(Make sure to update your system accordingly or /dev/zero won't work.) Cleaned up comments in MEMORY driver.
339 lines
10 KiB
C
339 lines
10 KiB
C
/* This file contains the device dependent part of the drivers for the
|
|
* following special files:
|
|
* /dev/ram - RAM disk
|
|
* /dev/mem - absolute memory
|
|
* /dev/kmem - kernel virtual memory
|
|
* /dev/null - null device (data sink)
|
|
* /dev/boot - boot device loaded from boot image
|
|
* /dev/zero - null byte stream generator
|
|
*
|
|
* Changes:
|
|
* Apr 29, 2005 added null byte generator (Jorrit N. Herder)
|
|
* Apr 09, 2005 added support for boot device (Jorrit N. Herder)
|
|
* Jul 26, 2004 moved RAM driver to user-space (Jorrit N. Herder)
|
|
* Apr 20, 1992 device dependent/independent split (Kees J. Bot)
|
|
*/
|
|
|
|
#include "../drivers.h"
|
|
#include "../libdriver/driver.h"
|
|
#include <sys/ioc_memory.h>
|
|
#include "../../kernel/const.h"
|
|
#include "../../kernel/config.h"
|
|
#include "../../kernel/type.h"
|
|
|
|
#include "assert.h"
|
|
|
|
#define NR_DEVS 6 /* number of minor devices */
|
|
|
|
PRIVATE struct device m_geom[NR_DEVS]; /* base and size of each device */
|
|
PRIVATE int m_seg[NR_DEVS]; /* segment index of each device */
|
|
PRIVATE int m_device; /* current device */
|
|
PRIVATE struct kinfo kinfo; /* kernel information */
|
|
PRIVATE struct machine machine; /* machine information */
|
|
|
|
extern int errno; /* error number for PM calls */
|
|
|
|
FORWARD _PROTOTYPE( char *m_name, (void) );
|
|
FORWARD _PROTOTYPE( struct device *m_prepare, (int device) );
|
|
FORWARD _PROTOTYPE( int m_transfer, (int proc_nr, int opcode, off_t position,
|
|
iovec_t *iov, unsigned nr_req) );
|
|
FORWARD _PROTOTYPE( int m_do_open, (struct driver *dp, message *m_ptr) );
|
|
FORWARD _PROTOTYPE( void m_init, (void) );
|
|
FORWARD _PROTOTYPE( int m_ioctl, (struct driver *dp, message *m_ptr) );
|
|
FORWARD _PROTOTYPE( void m_geometry, (struct partition *entry) );
|
|
|
|
/* Entry points to this driver. */
|
|
PRIVATE struct driver m_dtab = {
|
|
m_name, /* current device's name */
|
|
m_do_open, /* open or mount */
|
|
do_nop, /* nothing on a close */
|
|
m_ioctl, /* specify ram disk geometry */
|
|
m_prepare, /* prepare for I/O on a given minor device */
|
|
m_transfer, /* do the I/O */
|
|
nop_cleanup, /* no need to clean up */
|
|
m_geometry, /* memory device "geometry" */
|
|
nop_signal, /* system signals */
|
|
nop_alarm,
|
|
nop_cancel,
|
|
nop_select,
|
|
NULL
|
|
};
|
|
|
|
/* Buffer for the /dev/zero null byte feed. */
|
|
#define ZERO_BUF_SIZE 1024
|
|
PRIVATE char dev_zero[ZERO_BUF_SIZE];
|
|
|
|
#define click_to_round_k(n) \
|
|
((unsigned) ((((unsigned long) (n) << CLICK_SHIFT) + 512) / 1024))
|
|
|
|
|
|
/*===========================================================================*
|
|
* main *
|
|
*===========================================================================*/
|
|
PUBLIC void main(void)
|
|
{
|
|
/* Main program. Initialize the memory driver and start the main loop. */
|
|
m_init();
|
|
driver_task(&m_dtab);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* m_name *
|
|
*===========================================================================*/
|
|
PRIVATE char *m_name()
|
|
{
|
|
/* Return a name for the current device. */
|
|
static char name[] = "memory";
|
|
return name;
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* m_prepare *
|
|
*===========================================================================*/
|
|
PRIVATE struct device *m_prepare(device)
|
|
int device;
|
|
{
|
|
/* Prepare for I/O on a device: check if the minor device number is ok. */
|
|
if (device < 0 || device >= NR_DEVS) return(NIL_DEV);
|
|
m_device = device;
|
|
|
|
return(&m_geom[device]);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* m_transfer *
|
|
*===========================================================================*/
|
|
PRIVATE int m_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 */
|
|
{
|
|
/* Read or write one the driver's minor devices. */
|
|
phys_bytes mem_phys, user_phys;
|
|
int seg;
|
|
unsigned count, left, chunk;
|
|
vir_bytes user_vir;
|
|
struct device *dv;
|
|
unsigned long dv_size;
|
|
int s;
|
|
|
|
/* Get minor device number and check for /dev/null. */
|
|
dv = &m_geom[m_device];
|
|
dv_size = cv64ul(dv->dv_size);
|
|
|
|
while (nr_req > 0) {
|
|
|
|
/* How much to transfer and where to / from. */
|
|
count = iov->iov_size;
|
|
user_vir = iov->iov_addr;
|
|
|
|
switch (m_device) {
|
|
|
|
/* No copying; ignore request. */
|
|
case NULL_DEV:
|
|
if (opcode == DEV_GATHER) return(OK); /* always at EOF */
|
|
break;
|
|
|
|
/* Virtual copying. For RAM disk, kernel memory and boot device. */
|
|
case RAM_DEV:
|
|
case KMEM_DEV:
|
|
case BOOT_DEV:
|
|
if (position >= dv_size) return(OK); /* check for EOF */
|
|
if (position + count > dv_size) count = dv_size - position;
|
|
seg = m_seg[m_device];
|
|
|
|
if (opcode == DEV_GATHER) { /* copy actual data */
|
|
sys_vircopy(SELF,seg,position, proc_nr,D,user_vir, count);
|
|
} else {
|
|
sys_vircopy(proc_nr,D,user_vir, SELF,seg,position, count);
|
|
}
|
|
break;
|
|
|
|
/* Physical copying. Only used to access entire memory. */
|
|
case MEM_DEV:
|
|
if (position >= dv_size) return(OK); /* check for EOF */
|
|
if (position + count > dv_size) count = dv_size - position;
|
|
mem_phys = cv64ul(dv->dv_base) + position;
|
|
|
|
if (opcode == DEV_GATHER) { /* copy data */
|
|
sys_physcopy(NONE, PHYS_SEG, mem_phys,
|
|
proc_nr, D, user_vir, count);
|
|
} else {
|
|
sys_physcopy(proc_nr, D, user_vir,
|
|
NONE, PHYS_SEG, mem_phys, count);
|
|
}
|
|
break;
|
|
|
|
/* Null byte stream generator. */
|
|
case ZERO_DEV:
|
|
if (opcode == DEV_GATHER) {
|
|
left = count;
|
|
while (left > 0) {
|
|
chunk = (left > ZERO_BUF_SIZE) ? ZERO_BUF_SIZE : left;
|
|
if (OK != (s=sys_vircopy(SELF, D, (vir_bytes) dev_zero,
|
|
proc_nr, D, user_vir, chunk)))
|
|
report("MEM","sys_vircopy failed", s);
|
|
left -= chunk;
|
|
user_vir += chunk;
|
|
}
|
|
}
|
|
break;
|
|
|
|
/* Unknown (illegal) minor device. */
|
|
default:
|
|
return(EINVAL);
|
|
}
|
|
|
|
/* Book the number of bytes transferred. */
|
|
position += count;
|
|
iov->iov_addr += count;
|
|
if ((iov->iov_size -= count) == 0) { iov++; nr_req--; }
|
|
|
|
}
|
|
return(OK);
|
|
}
|
|
|
|
|
|
/*============================================================================*
|
|
* m_do_open *
|
|
*============================================================================*/
|
|
PRIVATE int m_do_open(dp, m_ptr)
|
|
struct driver *dp;
|
|
message *m_ptr;
|
|
{
|
|
/* Check device number on open. (This used to give I/O privileges to a
|
|
* process opening /dev/mem or /dev/kmem. This may be needed in case of
|
|
* memory mapped I/O. With system calls to do I/O this is no longer needed.)
|
|
*/
|
|
if (m_prepare(m_ptr->DEVICE) == NIL_DEV) return(ENXIO);
|
|
|
|
return(OK);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* m_init *
|
|
*===========================================================================*/
|
|
PRIVATE void m_init()
|
|
{
|
|
/* Initialize this task. All minor devices are initialized one by one. */
|
|
int i, s;
|
|
|
|
if (OK != (s=sys_getkinfo(&kinfo))) {
|
|
panic("MEM","Couldn't get kernel information.",s);
|
|
}
|
|
|
|
/* Install remote segment for /dev/kmem memory. */
|
|
m_geom[KMEM_DEV].dv_base = cvul64(kinfo.kmem_base);
|
|
m_geom[KMEM_DEV].dv_size = cvul64(kinfo.kmem_size);
|
|
if (OK != (s=sys_segctl(&m_seg[KMEM_DEV], (u16_t *) &s, (vir_bytes *) &s,
|
|
kinfo.kmem_base, kinfo.kmem_size))) {
|
|
panic("MEM","Couldn't install remote segment.",s);
|
|
}
|
|
|
|
/* Install remote segment for /dev/boot memory, if enabled. */
|
|
m_geom[BOOT_DEV].dv_base = cvul64(kinfo.bootdev_base);
|
|
m_geom[BOOT_DEV].dv_size = cvul64(kinfo.bootdev_size);
|
|
if (kinfo.bootdev_base > 0) {
|
|
if (OK != (s=sys_segctl(&m_seg[BOOT_DEV], (u16_t *) &s, (vir_bytes *) &s,
|
|
kinfo.bootdev_base, kinfo.bootdev_size))) {
|
|
panic("MEM","Couldn't install remote segment.",s);
|
|
}
|
|
}
|
|
|
|
/* Initialize /dev/zero. Simply write zeros into the buffer. */
|
|
for (i=0; i<ZERO_BUF_SIZE; i++) {
|
|
dev_zero[i] = '\0';
|
|
}
|
|
|
|
/* Set up memory ranges for /dev/mem. */
|
|
#if (CHIP == INTEL)
|
|
if (OK != (s=sys_getmachine(&machine))) {
|
|
panic("MEM","Couldn't get machine information.",s);
|
|
}
|
|
if (! machine.protected) {
|
|
m_geom[MEM_DEV].dv_size = cvul64(0x100000); /* 1M for 8086 systems */
|
|
} else {
|
|
#if _WORD_SIZE == 2
|
|
m_geom[MEM_DEV].dv_size = cvul64(0x1000000); /* 16M for 286 systems */
|
|
#else
|
|
m_geom[MEM_DEV].dv_size = cvul64(0xFFFFFFFF); /* 4G-1 for 386 systems */
|
|
#endif
|
|
}
|
|
#else /* !(CHIP == INTEL) */
|
|
#if (CHIP == M68000)
|
|
m_geom[MEM_DEV].dv_size = cvul64(MEM_BYTES);
|
|
#else /* !(CHIP == M68000) */
|
|
#error /* memory limit not set up */
|
|
#endif /* !(CHIP == M68000) */
|
|
#endif /* !(CHIP == INTEL) */
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* m_ioctl *
|
|
*===========================================================================*/
|
|
PRIVATE int m_ioctl(dp, m_ptr)
|
|
struct driver *dp; /* pointer to driver structure */
|
|
message *m_ptr; /* pointer to control message */
|
|
{
|
|
/* I/O controls for the memory driver. Currently there is one I/O control:
|
|
* - MIOCRAMSIZE: to set the size of the RAM disk.
|
|
*/
|
|
struct device *dv;
|
|
if ((dv = m_prepare(m_ptr->DEVICE)) == NIL_DEV) return(ENXIO);
|
|
|
|
switch (m_ptr->REQUEST) {
|
|
case MIOCRAMSIZE: {
|
|
/* FS wants to create a new RAM disk with the given size. */
|
|
phys_bytes ramdev_size;
|
|
phys_bytes ramdev_base;
|
|
message m;
|
|
int s;
|
|
|
|
if (m_ptr->PROC_NR != FS_PROC_NR) {
|
|
report("MEM", "warning, MIOCRAMSIZE called by", m_ptr->PROC_NR);
|
|
return(EPERM);
|
|
}
|
|
|
|
/* Try to allocate a piece of memory for the RAM disk. */
|
|
ramdev_size = m_ptr->POSITION;
|
|
if (allocmem(ramdev_size, &ramdev_base) < 0) {
|
|
report("MEM", "warning, allocmem failed", errno);
|
|
return(ENOMEM);
|
|
}
|
|
dv->dv_base = cvul64(ramdev_base);
|
|
dv->dv_size = cvul64(ramdev_size);
|
|
|
|
if (OK != (s=sys_segctl(&m_seg[RAM_DEV], (u16_t *) &s, (vir_bytes *) &s,
|
|
ramdev_base, ramdev_size))) {
|
|
panic("MEM","Couldn't install remote segment.",s);
|
|
}
|
|
break;
|
|
}
|
|
|
|
default:
|
|
return(do_diocntl(&m_dtab, m_ptr));
|
|
}
|
|
return(OK);
|
|
}
|
|
|
|
|
|
/*============================================================================*
|
|
* m_geometry *
|
|
*============================================================================*/
|
|
PRIVATE void m_geometry(entry)
|
|
struct partition *entry;
|
|
{
|
|
/* Memory devices don't have a geometry, but the outside world insists. */
|
|
entry->cylinders = div64u(m_geom[m_device].dv_size, SECTOR_SIZE) / (64 * 32);
|
|
entry->heads = 64;
|
|
entry->sectors = 32;
|
|
}
|
|
|
|
|