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minix/lib/libdriver/driver.c
David van Moolenbroek eeab8e0680 libdriver: make partition code use a contiguous buffer
2010-06-13 10:40:22 +00:00

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/* This file contains device independent device driver interface.
*
* Changes:
* Jul 25, 2005 added SYS_SIG type for signals (Jorrit N. Herder)
* Sep 15, 2004 added SYN_ALARM type for timeouts (Jorrit N. Herder)
* Jul 23, 2004 removed kernel dependencies (Jorrit N. Herder)
* Apr 02, 1992 constructed from AT wini and floppy driver (Kees J. Bot)
*
*
* The drivers support the following operations (using message format m2):
*
* m_type DEVICE IO_ENDPT COUNT POSITION HIGHPOS IO_GRANT
* ----------------------------------------------------------------------------
* | DEV_OPEN | device | proc nr | | | | |
* |---------------+--------+---------+---------+--------+--------+-----------|
* | DEV_CLOSE | device | proc nr | | | | |
* |---------------+--------+---------+---------+--------+--------+-----------|
* | DEV_READ_S | device | proc nr | bytes | off lo | off hi i buf grant |
* |---------------+--------+---------+---------+--------+--------+-----------|
* | DEV_WRITE_S | device | proc nr | bytes | off lo | off hi | buf grant |
* |---------------+--------+---------+---------+--------+--------+-----------|
* | DEV_GATHER_S | device | proc nr | iov len | off lo | off hi | iov grant |
* |---------------+--------+---------+---------+--------+--------+-----------|
* | DEV_SCATTER_S | device | proc nr | iov len | off lo | off hi | iov grant |
* |---------------+--------+---------+---------+--------+--------+-----------|
* | DEV_IOCTL_S | device | proc nr | request | | | buf grant |
* |---------------+--------+---------+---------+--------+--------+-----------|
* | CANCEL | device | proc nr | r/w | | | |
* ----------------------------------------------------------------------------
*
* The file contains the following entry points:
*
* driver_announce: called by a device driver to announce it is up
* driver_receive: receive() interface for drivers
* driver_receive_mq: receive() interface for drivers with message queueing
* driver_task: called by the device dependent task entry
* driver_init_buffer: initialize a DMA buffer
* driver_mq_queue: queue an incoming message for later processing
*/
#include <minix/drivers.h>
#include <sys/ioc_disk.h>
#include <minix/mq.h>
#include <minix/endpoint.h>
#include <minix/driver.h>
#include <minix/ds.h>
/* Claim space for variables. */
u8_t *tmp_buf = NULL; /* the DMA buffer eventually */
phys_bytes tmp_phys; /* phys address of DMA buffer */
FORWARD _PROTOTYPE( void clear_open_devs, (void) );
FORWARD _PROTOTYPE( int is_open_dev, (int device) );
FORWARD _PROTOTYPE( void set_open_dev, (int device) );
FORWARD _PROTOTYPE( void asyn_reply, (message *mess, int proc_nr, int r) );
FORWARD _PROTOTYPE( int driver_reply, (endpoint_t caller_e, int caller_status,
message *m_ptr) );
FORWARD _PROTOTYPE( int driver_spurious_reply, (endpoint_t caller_e,
int caller_status, message *m_ptr) );
FORWARD _PROTOTYPE( int do_rdwt, (struct driver *dr, message *mp) );
FORWARD _PROTOTYPE( int do_vrdwt, (struct driver *dr, message *mp) );
int device_caller;
PRIVATE mq_t *queue_head = NULL;
PRIVATE int open_devs[MAX_NR_OPEN_DEVICES];
PRIVATE int next_open_devs_slot = 0;
/*===========================================================================*
* clear_open_devs *
*===========================================================================*/
PRIVATE void clear_open_devs()
{
next_open_devs_slot = 0;
}
/*===========================================================================*
* is_open_dev *
*===========================================================================*/
PRIVATE int is_open_dev(int device)
{
int i, open_dev_found;
open_dev_found = FALSE;
for(i=0;i<next_open_devs_slot;i++) {
if(open_devs[i] == device) {
open_dev_found = TRUE;
break;
}
}
return open_dev_found;
}
/*===========================================================================*
* set_open_dev *
*===========================================================================*/
PRIVATE void set_open_dev(int device)
{
if(next_open_devs_slot >= MAX_NR_OPEN_DEVICES) {
panic("out of slots for open devices");
}
open_devs[next_open_devs_slot] = device;
next_open_devs_slot++;
}
/*===========================================================================*
* asyn_reply *
*===========================================================================*/
PRIVATE void asyn_reply(mess, proc_nr, r)
message *mess;
int proc_nr;
int r;
{
/* Send a reply using the new asynchronous character device protocol.
*/
message reply_mess;
switch (mess->m_type) {
case DEV_OPEN:
reply_mess.m_type = DEV_REVIVE;
reply_mess.REP_ENDPT = proc_nr;
reply_mess.REP_STATUS = r;
break;
case DEV_CLOSE:
reply_mess.m_type = DEV_CLOSE_REPL;
reply_mess.REP_ENDPT = proc_nr;
reply_mess.REP_STATUS = r;
break;
case DEV_READ_S:
case DEV_WRITE_S:
if (r == SUSPEND)
printf("driver_task: reviving %d with SUSPEND\n", proc_nr);
reply_mess.m_type = DEV_REVIVE;
reply_mess.REP_ENDPT = proc_nr;
reply_mess.REP_IO_GRANT = (cp_grant_id_t) mess->IO_GRANT;
reply_mess.REP_STATUS = r;
break;
case CANCEL:
/* The original request should send a reply. */
return;
case DEV_SELECT:
reply_mess.m_type = DEV_SEL_REPL1;
reply_mess.DEV_MINOR = mess->DEVICE;
reply_mess.DEV_SEL_OPS = r;
break;
default:
reply_mess.m_type = TASK_REPLY;
reply_mess.REP_ENDPT = proc_nr;
/* Status is # of bytes transferred or error code. */
reply_mess.REP_STATUS = r;
break;
}
r= asynsend(device_caller, &reply_mess);
if (r != OK)
{
printf("driver_task: unable to asynsend to %d: %d\n",
device_caller, r);
}
}
/*===========================================================================*
* driver_reply *
*===========================================================================*/
PRIVATE int driver_reply(caller_e, caller_status, m_ptr)
endpoint_t caller_e;
int caller_status;
message *m_ptr;
{
/* Reply to a message sent to the driver. */
int r;
/* Use sendnb if caller is guaranteed to be blocked, asynsend otherwise. */
if(IPC_STATUS_CALL(caller_status) == SENDREC) {
r = sendnb(caller_e, m_ptr);
}
else {
r = asynsend(caller_e, m_ptr);
}
return r;
}
/*===========================================================================*
* driver_spurious_reply *
*===========================================================================*/
PRIVATE int driver_spurious_reply(caller_e, caller_status, m_ptr)
endpoint_t caller_e;
int caller_status;
message *m_ptr;
{
/* Reply to a spurious message pretending to be dead. */
int r;
m_ptr->m_type = TASK_REPLY;
m_ptr->REP_ENDPT = m_ptr->IO_ENDPT;
m_ptr->REP_STATUS = ERESTART;
r = driver_reply(caller_e, caller_status, m_ptr);
if(r != OK) {
printf("unable to reply to spurious message from %d\n",
caller_e);
}
return r;
}
/*===========================================================================*
* driver_announce *
*===========================================================================*/
PUBLIC void driver_announce()
{
/* Announce we are up after a fresh start or restart. */
int r;
char key[DS_MAX_KEYLEN];
char label[DS_MAX_KEYLEN];
char *driver_prefix = "drv.vfs.";
/* Callers are allowed to use sendrec to communicate with drivers.
* For this reason, there may blocked callers when a driver restarts.
* Ask the kernel to unblock them (if any).
*/
r = sys_statectl(SYS_STATE_CLEAR_IPC_REFS);
if (r != OK) {
panic("driver_announce: sys_statectl failed: %d\n", r);
}
/* Publish a driver up event. */
r = ds_retrieve_label_name(label, getprocnr());
if (r != OK) {
panic("driver_announce: unable to get own label: %d\n", r);
}
snprintf(key, DS_MAX_KEYLEN, "%s%s", driver_prefix, label);
r = ds_publish_u32(key, DS_DRIVER_UP, DSF_OVERWRITE);
if (r != OK) {
panic("driver_announce: unable to publish driver up event: %d\n", r);
}
/* Expect a DEV_OPEN for any device before serving regular driver requests. */
clear_open_devs();
}
/*===========================================================================*
* driver_receive *
*===========================================================================*/
PUBLIC int driver_receive(src, m_ptr, status_ptr)
endpoint_t src;
message *m_ptr;
int *status_ptr;
{
/* receive() interface for drivers. */
int r;
int ipc_status;
while (TRUE) {
/* Wait for a request. */
r = sef_receive_status(src, m_ptr, &ipc_status);
*status_ptr = ipc_status;
if (r != OK) {
return r;
}
/* See if only DEV_OPEN is to be expected for this device. */
if(IS_DEV_MINOR_RQ(m_ptr->m_type) && !is_open_dev(m_ptr->DEVICE)) {
if(m_ptr->m_type != DEV_OPEN) {
if(!is_ipc_asynch(ipc_status)) {
driver_spurious_reply(m_ptr->m_source,
ipc_status, m_ptr);
}
continue;
}
set_open_dev(m_ptr->DEVICE);
}
break;
}
return OK;
}
/*===========================================================================*
* driver_receive_mq *
*===========================================================================*/
PUBLIC int driver_receive_mq(m_ptr, status_ptr)
message *m_ptr;
int *status_ptr;
{
/* receive() interface for drivers with message queueing. */
int ipc_status;
/* Any queued messages? Oldest are at the head. */
while(queue_head) {
mq_t *mq;
mq = queue_head;
memcpy(m_ptr, &mq->mq_mess, sizeof(mq->mq_mess));
ipc_status = mq->mq_mess_status;
*status_ptr = ipc_status;
queue_head = queue_head->mq_next;
mq_free(mq);
/* See if only DEV_OPEN is to be expected for this device. */
if(IS_DEV_MINOR_RQ(m_ptr->m_type) && !is_open_dev(m_ptr->DEVICE)) {
if(m_ptr->m_type != DEV_OPEN) {
if(!is_ipc_asynch(ipc_status)) {
driver_spurious_reply(m_ptr->m_source,
ipc_status, m_ptr);
}
continue;
}
set_open_dev(m_ptr->DEVICE);
}
return OK;
}
/* Fall back to standard receive() interface for drivers. */
return driver_receive(ANY, m_ptr, status_ptr);
}
/*===========================================================================*
* driver_task *
*===========================================================================*/
PUBLIC void driver_task(dp, type)
struct driver *dp; /* Device dependent entry points. */
int type; /* Driver type (DRIVER_STD or DRIVER_ASYN) */
{
/* Main program of any device driver task. */
int r, proc_nr, ipc_status;
message mess;
/* Here is the main loop of the disk task. It waits for a message, carries
* it out, and sends a reply.
*/
while (TRUE) {
if ((r=driver_receive_mq(&mess, &ipc_status)) != OK)
panic("driver_receive_mq failed: %d", r);
device_caller = mess.m_source;
proc_nr = mess.IO_ENDPT;
/* Now carry out the work. */
if (is_ipc_notify(ipc_status)) {
switch (_ENDPOINT_P(mess.m_source)) {
case HARDWARE:
/* leftover interrupt or expired timer. */
if(dp->dr_hw_int) {
(*dp->dr_hw_int)(dp, &mess);
}
break;
case CLOCK:
(*dp->dr_alarm)(dp, &mess);
break;
default:
if(dp->dr_other)
r = (*dp->dr_other)(dp, &mess);
else
r = EINVAL;
goto send_reply;
}
/* done, get a new message */
continue;
}
switch(mess.m_type) {
case DEV_OPEN: r = (*dp->dr_open)(dp, &mess); break;
case DEV_CLOSE: r = (*dp->dr_close)(dp, &mess); break;
case DEV_IOCTL_S: r = (*dp->dr_ioctl)(dp, &mess); break;
case CANCEL: r = (*dp->dr_cancel)(dp, &mess);break;
case DEV_SELECT: r = (*dp->dr_select)(dp, &mess);break;
case DEV_READ_S:
case DEV_WRITE_S: r = do_rdwt(dp, &mess); break;
case DEV_GATHER_S:
case DEV_SCATTER_S: r = do_vrdwt(dp, &mess); break;
default:
if(dp->dr_other)
r = (*dp->dr_other)(dp, &mess);
else
r = EINVAL;
break;
}
send_reply:
/* Clean up leftover state. */
(*dp->dr_cleanup)();
/* Finally, prepare and send the reply message. */
if (r == EDONTREPLY)
continue;
switch (type) {
case DRIVER_STD:
mess.m_type = TASK_REPLY;
mess.REP_ENDPT = proc_nr;
/* Status is # of bytes transferred or error code. */
mess.REP_STATUS = r;
r= driver_reply(device_caller, ipc_status, &mess);
if (r != OK)
{
printf("driver_task: unable to send reply to %d: %d\n",
device_caller, r);
}
break;
case DRIVER_ASYN:
asyn_reply(&mess, proc_nr, r);
break;
default:
panic("unknown driver type: %d", type);
}
}
}
/*===========================================================================*
* driver_init_buffer *
*===========================================================================*/
PUBLIC void driver_init_buffer(void)
{
/* Select a buffer that can safely be used for DMA transfers. It may also
* be used to read partition tables and such. Its absolute address is
* 'tmp_phys', the normal address is 'tmp_buf'.
*/
vir_bytes size;
if (tmp_buf == NULL) {
size = MAX(2*DMA_BUF_SIZE, CD_SECTOR_SIZE);
if(!(tmp_buf = alloc_contig(size, AC_ALIGN4K, &tmp_phys)))
panic("can't allocate tmp_buf: %lu", size);
}
}
/*===========================================================================*
* do_rdwt *
*===========================================================================*/
PRIVATE int do_rdwt(dp, mp)
struct driver *dp; /* device dependent entry points */
message *mp; /* pointer to read or write message */
{
/* Carry out a single read or write request. */
iovec_t iovec1;
int r, opcode;
u64_t position;
/* Disk address? Address and length of the user buffer? */
if (mp->COUNT < 0) return(EINVAL);
/* Prepare for I/O. */
if ((*dp->dr_prepare)(mp->DEVICE) == NULL) return(ENXIO);
/* Create a one element scatter/gather vector for the buffer. */
if(mp->m_type == DEV_READ_S) opcode = DEV_GATHER_S;
else opcode = DEV_SCATTER_S;
iovec1.iov_addr = (vir_bytes) mp->IO_GRANT;
iovec1.iov_size = mp->COUNT;
/* Transfer bytes from/to the device. */
position= make64(mp->POSITION, mp->HIGHPOS);
r = (*dp->dr_transfer)(mp->IO_ENDPT, opcode, position, &iovec1, 1);
/* Return the number of bytes transferred or an error code. */
return(r == OK ? (mp->COUNT - iovec1.iov_size) : r);
}
/*==========================================================================*
* do_vrdwt *
*==========================================================================*/
PRIVATE int do_vrdwt(dp, mp)
struct driver *dp; /* device dependent entry points */
message *mp; /* pointer to read or write message */
{
/* Carry out an device read or write to/from a vector of user addresses.
* The "user addresses" are assumed to be safe, i.e. FS transferring to/from
* its own buffers, so they are not checked.
*/
static iovec_t iovec[NR_IOREQS];
phys_bytes iovec_size;
unsigned nr_req;
int r, opcode;
u64_t position;
nr_req = mp->COUNT; /* Length of I/O vector */
/* Copy the vector from the caller to kernel space. */
if (nr_req > NR_IOREQS) nr_req = NR_IOREQS;
iovec_size = (phys_bytes) (nr_req * sizeof(iovec[0]));
if (OK != sys_safecopyfrom(mp->m_source, (vir_bytes) mp->IO_GRANT,
0, (vir_bytes) iovec, iovec_size, D)) {
panic("bad I/O vector by: %d", mp->m_source);
}
/* Prepare for I/O. */
if ((*dp->dr_prepare)(mp->DEVICE) == NULL) return(ENXIO);
/* Transfer bytes from/to the device. */
opcode = mp->m_type;
position= make64(mp->POSITION, mp->HIGHPOS);
r = (*dp->dr_transfer)(mp->IO_ENDPT, opcode, position, iovec, nr_req);
/* Copy the I/O vector back to the caller. */
if (OK != sys_safecopyto(mp->m_source, (vir_bytes) mp->IO_GRANT,
0, (vir_bytes) iovec, iovec_size, D)) {
panic("couldn't return I/O vector: %d", mp->m_source);
}
return(r);
}
/*===========================================================================*
* no_name *
*===========================================================================*/
PUBLIC char *no_name()
{
/* Use this default name if there is no specific name for the device. This was
* originally done by fetching the name from the task table for this process:
* "return(tasktab[proc_number(proc_ptr) + NR_TASKS].name);", but currently a
* real "noname" is returned. Perhaps, some system information service can be
* queried for a name at a later time.
*/
static char name[] = "noname";
return name;
}
/*============================================================================*
* do_nop *
*============================================================================*/
PUBLIC int do_nop(dp, mp)
struct driver *dp;
message *mp;
{
/* Nothing there, or nothing to do. */
switch (mp->m_type) {
case DEV_OPEN: return(ENODEV);
case DEV_CLOSE: return(OK);
case DEV_IOCTL_S:
default: printf("nop: ignoring code %d\n", mp->m_type);
return(EIO);
}
}
/*============================================================================*
* nop_ioctl *
*============================================================================*/
PUBLIC int nop_ioctl(dp, mp)
struct driver *dp;
message *mp;
{
return(ENOTTY);
}
/*============================================================================*
* nop_alarm *
*============================================================================*/
PUBLIC void nop_alarm(dp, mp)
struct driver *dp;
message *mp;
{
/* Ignore the leftover alarm. */
}
/*===========================================================================*
* nop_prepare *
*===========================================================================*/
PUBLIC struct device *nop_prepare(int device)
{
/* Nothing to prepare for. */
return(NULL);
}
/*===========================================================================*
* nop_cleanup *
*===========================================================================*/
PUBLIC void nop_cleanup()
{
/* Nothing to clean up. */
}
/*===========================================================================*
* nop_cancel *
*===========================================================================*/
PUBLIC int nop_cancel(struct driver *dr, message *m)
{
/* Nothing to do for cancel. */
return(OK);
}
/*===========================================================================*
* nop_select *
*===========================================================================*/
PUBLIC int nop_select(struct driver *dr, message *m)
{
/* Nothing to do for select. */
return(OK);
}
/*============================================================================*
* do_diocntl *
*============================================================================*/
PUBLIC int do_diocntl(dp, mp)
struct driver *dp;
message *mp; /* pointer to ioctl request */
{
/* Carry out a partition setting/getting request. */
struct device *dv;
struct partition entry;
int s;
if (mp->REQUEST != DIOCSETP && mp->REQUEST != DIOCGETP) {
if(dp->dr_other) {
return dp->dr_other(dp, mp);
} else return(ENOTTY);
}
/* Decode the message parameters. */
if ((dv = (*dp->dr_prepare)(mp->DEVICE)) == NULL) return(ENXIO);
if (mp->REQUEST == DIOCSETP) {
/* Copy just this one partition table entry. */
s=sys_safecopyfrom(mp->IO_ENDPT, (vir_bytes) mp->IO_GRANT,
0, (vir_bytes) &entry, sizeof(entry), D);
if(s != OK)
return s;
dv->dv_base = entry.base;
dv->dv_size = entry.size;
} else {
/* Return a partition table entry and the geometry of the drive. */
entry.base = dv->dv_base;
entry.size = dv->dv_size;
(*dp->dr_geometry)(&entry);
s=sys_safecopyto(mp->IO_ENDPT, (vir_bytes) mp->IO_GRANT,
0, (vir_bytes) &entry, sizeof(entry), D);
if (OK != s)
return s;
}
return(OK);
}
/*===========================================================================*
* driver_mq_queue *
*===========================================================================*/
PUBLIC int driver_mq_queue(message *m, int status)
{
mq_t *mq, *mi;
static int mq_initialized = FALSE;
if(!mq_initialized) {
/* Init MQ library. */
mq_init();
mq_initialized = TRUE;
}
if(!(mq = mq_get()))
panic("driver_mq_queue: mq_get failed");
memcpy(&mq->mq_mess, m, sizeof(mq->mq_mess));
mq->mq_mess_status = status;
mq->mq_next = NULL;
if(!queue_head) {
queue_head = mq;
} else {
for(mi = queue_head; mi->mq_next; mi = mi->mq_next)
;
mi->mq_next = mq;
}
return OK;
}
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