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