2bfeeed885
. all invocations were S or D, so can safely be dropped to prepare for the segmentless world . still assign D to the SCP_SEG field in the message to make previous kernels usable
470 lines
15 KiB
C
470 lines
15 KiB
C
/* This file contains the device independent character driver interface.
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*
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* The drivers support the following operations (using message format m2):
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*
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* m_type DEVICE USER_ENDPT COUNT POSITION HIGHPOS IO_GRANT
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* ----------------------------------------------------------------------------
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* | DEV_OPEN | device | proc nr | mode | | | |
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* |---------------+--------+---------+---------+--------+--------+-----------|
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* | DEV_CLOSE | device | proc nr | | | | |
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* |---------------+--------+---------+---------+--------+--------+-----------|
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* | DEV_READ_S | device | proc nr | bytes | off lo | off hi i buf grant |
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* |---------------+--------+---------+---------+--------+--------+-----------|
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* | DEV_WRITE_S | device | proc nr | bytes | off lo | off hi | buf grant |
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* |---------------+--------+---------+---------+--------+--------+-----------|
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* | DEV_GATHER_S | device | proc nr | iov len | off lo | off hi | iov grant |
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* |---------------+--------+---------+---------+--------+--------+-----------|
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* | DEV_SCATTER_S | device | proc nr | iov len | off lo | off hi | iov grant |
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* |---------------+--------+---------+---------+--------+--------+-----------|
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* | DEV_IOCTL_S | device | proc nr | request | | | buf grant |
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* |---------------+--------+---------+---------+--------+--------+-----------|
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* | CANCEL | device | proc nr | r/w | | | grant |
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* |---------------+--------+---------+---------+--------+--------+-----------|
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* | DEV_SELECT | device | ops | | | | |
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* ----------------------------------------------------------------------------
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*
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* The entry points into this file are:
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* driver_task: the main message loop of the driver
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* driver_receive: message receive interface for drivers
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*
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* Changes:
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* Oct 16, 2011 split character and block protocol (D.C. van Moolenbroek)
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* Aug 27, 2011 move common functions into driver.c (A. Welzel)
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* Jul 25, 2005 added SYS_SIG type for signals (Jorrit N. Herder)
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* Sep 15, 2004 added SYN_ALARM type for timeouts (Jorrit N. Herder)
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* Jul 23, 2004 removed kernel dependencies (Jorrit N. Herder)
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* Apr 02, 1992 constructed from AT wini and floppy driver (Kees J. Bot)
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*/
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#include <minix/drivers.h>
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#include <minix/chardriver.h>
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#include <minix/ds.h>
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static int running;
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/* Management data for opened devices. */
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static int open_devs[MAX_NR_OPEN_DEVICES];
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static int next_open_devs_slot = 0;
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/*===========================================================================*
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* clear_open_devs *
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*===========================================================================*/
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static void clear_open_devs(void)
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{
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/* Reset the set of previously opened minor devices. */
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next_open_devs_slot = 0;
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}
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/*===========================================================================*
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* is_open_dev *
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*===========================================================================*/
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static int is_open_dev(int device)
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{
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/* Check whether the given minor device has previously been opened. */
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int i;
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for (i = 0; i < next_open_devs_slot; i++)
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if (open_devs[i] == device)
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return TRUE;
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return FALSE;
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}
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/*===========================================================================*
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* set_open_dev *
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*===========================================================================*/
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static void set_open_dev(int device)
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{
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/* Mark the given minor device as having been opened. */
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if (next_open_devs_slot >= MAX_NR_OPEN_DEVICES)
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panic("out of slots for open devices");
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open_devs[next_open_devs_slot] = device;
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next_open_devs_slot++;
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}
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/*===========================================================================*
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* chardriver_announce *
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*===========================================================================*/
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void chardriver_announce(void)
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{
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/* Announce we are up after a fresh start or restart. */
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int r;
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char key[DS_MAX_KEYLEN];
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char label[DS_MAX_KEYLEN];
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char *driver_prefix = "drv.chr.";
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/* Callers are allowed to use sendrec to communicate with drivers.
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* For this reason, there may blocked callers when a driver restarts.
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* Ask the kernel to unblock them (if any).
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*/
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#if USE_STATECTL
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if ((r = sys_statectl(SYS_STATE_CLEAR_IPC_REFS)) != OK)
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panic("chardriver_init: sys_statectl failed: %d", r);
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#endif
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/* Publish a driver up event. */
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if ((r = ds_retrieve_label_name(label, getprocnr())) != OK)
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panic("chardriver_init: unable to get own label: %d", r);
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snprintf(key, DS_MAX_KEYLEN, "%s%s", driver_prefix, label);
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if ((r = ds_publish_u32(key, DS_DRIVER_UP, DSF_OVERWRITE)) != OK)
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panic("chardriver_init: unable to publish driver up event: %d", r);
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/* Expect a DEV_OPEN for any device before serving regular driver requests. */
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clear_open_devs();
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}
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/*===========================================================================*
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* async_reply *
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*===========================================================================*/
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static void async_reply(message *mess, int r)
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{
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/* Send a reply using the asynchronous character device protocol. */
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message reply_mess;
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/* Do not reply with ERESTART in this protocol. The only possible caller,
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* VFS, will find out through other means when we have restarted, and is not
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* (fully) ready to deal with ERESTART errors.
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*/
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if (r == ERESTART)
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return;
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switch (mess->m_type) {
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case DEV_OPEN:
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reply_mess.m_type = DEV_OPEN_REPL;
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reply_mess.REP_ENDPT = mess->USER_ENDPT;
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reply_mess.REP_STATUS = r;
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break;
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case DEV_CLOSE:
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reply_mess.m_type = DEV_CLOSE_REPL;
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reply_mess.REP_ENDPT = mess->USER_ENDPT;
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reply_mess.REP_STATUS = r;
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break;
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case DEV_READ_S:
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case DEV_WRITE_S:
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case DEV_IOCTL_S:
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if (r == SUSPEND)
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printf("driver_task: reviving %d (%d) with SUSPEND\n",
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mess->m_source, mess->USER_ENDPT);
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reply_mess.m_type = DEV_REVIVE;
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reply_mess.REP_ENDPT = mess->USER_ENDPT;
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reply_mess.REP_IO_GRANT = (cp_grant_id_t) mess->IO_GRANT;
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reply_mess.REP_STATUS = r;
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break;
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case CANCEL:
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/* The original request should send a reply. */
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return;
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case DEV_SELECT:
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reply_mess.m_type = DEV_SEL_REPL1;
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reply_mess.DEV_MINOR = mess->DEVICE;
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reply_mess.DEV_SEL_OPS = r;
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break;
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default:
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reply_mess.m_type = TASK_REPLY;
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reply_mess.REP_ENDPT = mess->USER_ENDPT;
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/* Status is # of bytes transferred or error code. */
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reply_mess.REP_STATUS = r;
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break;
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}
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r = asynsend(mess->m_source, &reply_mess);
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if (r != OK)
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printf("asyn_reply: unable to asynsend reply to %d: %d\n",
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mess->m_source, r);
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}
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/*===========================================================================*
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* sync_reply *
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*===========================================================================*/
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static void sync_reply(message *m_ptr, int ipc_status, int reply)
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{
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/* Reply to a message sent to the driver. */
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endpoint_t caller_e, user_e;
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int r;
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caller_e = m_ptr->m_source;
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user_e = m_ptr->USER_ENDPT;
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m_ptr->m_type = TASK_REPLY;
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m_ptr->REP_ENDPT = user_e;
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m_ptr->REP_STATUS = reply;
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/* If we would block sending the message, send it asynchronously. */
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if (IPC_STATUS_CALL(ipc_status) == SENDREC)
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r = sendnb(caller_e, m_ptr);
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else
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r = asynsend(caller_e, m_ptr);
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if (r != OK)
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printf("driver_reply: unable to send reply to %d: %d\n", caller_e, r);
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}
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/*===========================================================================*
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* send_reply *
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*===========================================================================*/
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static void send_reply(int type, message *m_ptr, int ipc_status, int reply)
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{
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/* Prepare and send a reply message. */
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if (reply == EDONTREPLY)
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return;
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if (type == CHARDRIVER_ASYNC)
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async_reply(m_ptr, reply);
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else
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sync_reply(m_ptr, ipc_status, reply);
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}
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/*===========================================================================*
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* do_rdwt *
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*===========================================================================*/
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static int do_rdwt(struct chardriver *cdp, message *mp)
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{
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/* Carry out a single read or write request. */
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iovec_t iovec1;
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int r, opcode;
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u64_t position;
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/* Disk address? Address and length of the user buffer? */
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if (mp->COUNT < 0) return(EINVAL);
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/* Prepare for I/O. */
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if ((*cdp->cdr_prepare)(mp->DEVICE) == NULL) return(ENXIO);
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/* Create a one element scatter/gather vector for the buffer. */
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if(mp->m_type == DEV_READ_S)
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opcode = DEV_GATHER_S;
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else
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opcode = DEV_SCATTER_S;
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iovec1.iov_addr = (vir_bytes) mp->IO_GRANT;
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iovec1.iov_size = mp->COUNT;
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/* Transfer bytes from/to the device. */
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position= make64(mp->POSITION, mp->HIGHPOS);
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r = (*cdp->cdr_transfer)(mp->m_source, opcode, position, &iovec1, 1,
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mp->USER_ENDPT, mp->FLAGS);
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/* Return the number of bytes transferred or an error code. */
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return(r == OK ? (int) (mp->COUNT - iovec1.iov_size) : r);
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}
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/*===========================================================================*
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* do_vrdwt *
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*===========================================================================*/
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static int do_vrdwt(struct chardriver *cdp, message *mp)
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{
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/* Carry out an device read or write to/from a vector of user addresses.
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* The "user addresses" are assumed to be safe, i.e. FS transferring to/from
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* its own buffers, so they are not checked.
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*/
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iovec_t iovec[NR_IOREQS];
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phys_bytes iovec_size;
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unsigned nr_req;
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int r, opcode;
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u64_t position;
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nr_req = mp->COUNT; /* Length of I/O vector */
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/* Copy the vector from the caller to kernel space. */
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if (nr_req > NR_IOREQS) nr_req = NR_IOREQS;
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iovec_size = (phys_bytes) (nr_req * sizeof(iovec[0]));
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if (OK != sys_safecopyfrom(mp->m_source, (vir_bytes) mp->IO_GRANT,
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0, (vir_bytes) iovec, iovec_size)) {
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printf("bad I/O vector by: %d\n", mp->m_source);
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return(EINVAL);
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}
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/* Prepare for I/O. */
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if ((*cdp->cdr_prepare)(mp->DEVICE) == NULL) return(ENXIO);
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/* Transfer bytes from/to the device. */
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opcode = mp->m_type;
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position= make64(mp->POSITION, mp->HIGHPOS);
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r = (*cdp->cdr_transfer)(mp->m_source, opcode, position, iovec, nr_req,
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mp->USER_ENDPT, mp->FLAGS);
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/* Copy the I/O vector back to the caller. */
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if (OK != sys_safecopyto(mp->m_source, (vir_bytes) mp->IO_GRANT,
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0, (vir_bytes) iovec, iovec_size)) {
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printf("couldn't return I/O vector: %d\n", mp->m_source);
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return(EINVAL);
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}
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return(r);
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}
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/*===========================================================================*
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* handle_notify *
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*===========================================================================*/
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static void handle_notify(struct chardriver *cdp, message *m_ptr)
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{
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/* Take care of the notifications (interrupt and clock messages) by calling the
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* appropiate callback functions. Never send a reply.
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*/
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/* Call the appropriate function for this notification. */
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switch (_ENDPOINT_P(m_ptr->m_source)) {
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case CLOCK:
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if (cdp->cdr_alarm)
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cdp->cdr_alarm(m_ptr);
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break;
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default:
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if (cdp->cdr_other)
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(void) cdp->cdr_other(m_ptr);
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}
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}
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/*===========================================================================*
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* handle_request *
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*===========================================================================*/
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static int handle_request(struct chardriver *cdp, message *m_ptr)
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{
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/* Call the appropiate driver function, based on the type of request. Return
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* the result code that is to be sent back to the caller, or EDONTREPLY if no
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* reply is to be sent.
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*/
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int r;
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/* We might get spurious requests if the driver has been restarted. Deny any
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* requests on devices that have not previously been opened, signaling the
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* caller that something went wrong.
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*/
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if (IS_CDEV_MINOR_RQ(m_ptr->m_type) && !is_open_dev(m_ptr->DEVICE)) {
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/* Reply ERESTART to spurious requests for unopened devices. */
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if (m_ptr->m_type != DEV_OPEN)
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return ERESTART;
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/* Mark the device as opened otherwise. */
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set_open_dev(m_ptr->DEVICE);
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}
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/* Call the appropriate function(s) for this request. */
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switch (m_ptr->m_type) {
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case DEV_OPEN: r = (*cdp->cdr_open)(m_ptr); break;
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case DEV_CLOSE: r = (*cdp->cdr_close)(m_ptr); break;
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case DEV_IOCTL_S: r = (*cdp->cdr_ioctl)(m_ptr); break;
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case CANCEL: r = (*cdp->cdr_cancel)(m_ptr); break;
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case DEV_SELECT: r = (*cdp->cdr_select)(m_ptr); break;
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case DEV_READ_S:
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case DEV_WRITE_S: r = do_rdwt(cdp, m_ptr); break;
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case DEV_GATHER_S:
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case DEV_SCATTER_S: r = do_vrdwt(cdp, m_ptr); break;
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default:
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if (cdp->cdr_other)
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r = cdp->cdr_other(m_ptr);
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else
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r = EINVAL;
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}
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/* Let the driver perform any cleanup. */
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if (cdp->cdr_cleanup)
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(*cdp->cdr_cleanup)();
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return r;
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}
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/*===========================================================================*
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* chardriver_process *
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*===========================================================================*/
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void chardriver_process(struct chardriver *cdp, int driver_type,
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message *m_ptr, int ipc_status)
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{
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/* Handle the given received message. */
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int r;
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/* Process the notification or request. */
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if (is_ipc_notify(ipc_status)) {
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handle_notify(cdp, m_ptr);
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/* Do not reply to notifications. */
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} else {
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r = handle_request(cdp, m_ptr);
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send_reply(driver_type, m_ptr, ipc_status, r);
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}
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}
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/*===========================================================================*
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* chardriver_task *
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*===========================================================================*/
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void chardriver_task(struct chardriver *cdp, int driver_type)
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{
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/* Main program of any device driver task. */
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int r, ipc_status;
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message mess;
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running = TRUE;
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/* Here is the main loop of the disk task. It waits for a message, carries
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* it out, and sends a reply.
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*/
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while (running) {
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if ((r = sef_receive_status(ANY, &mess, &ipc_status)) != OK)
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panic("driver_receive failed: %d", r);
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chardriver_process(cdp, driver_type, &mess, ipc_status);
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}
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}
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/*===========================================================================*
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* do_nop *
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*===========================================================================*/
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int do_nop(message *UNUSED(mp))
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{
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return(OK);
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}
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/*===========================================================================*
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* nop_ioctl *
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*===========================================================================*/
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int nop_ioctl(message *UNUSED(mp))
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{
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return(ENOTTY);
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}
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/*===========================================================================*
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* nop_alarm *
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*===========================================================================*/
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void nop_alarm(message *UNUSED(mp))
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{
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/* Ignore the leftover alarm. */
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}
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/*===========================================================================*
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* nop_cleanup *
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*===========================================================================*/
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void nop_cleanup(void)
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{
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/* Nothing to clean up. */
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}
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/*===========================================================================*
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* nop_cancel *
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*===========================================================================*/
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int nop_cancel(message *UNUSED(m))
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{
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/* Nothing to do for cancel. */
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return(OK);
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}
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/*===========================================================================*
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* nop_select *
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*===========================================================================*/
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int nop_select(message *UNUSED(m))
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{
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/* Nothing to do for select. */
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return(OK);
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}
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