viocons.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,334 行 · 第 1/3 页

	size_t curlen;
	const char *curbuf;
	unsigned long flags;
	int copy_needed = (viochar == NULL);

	/*
	 * Write to the hvlog of inbound data are now done prior to
	 * calling internal_write() since internal_write() is only called in
	 * the event that an lp event path is active, which isn't the case for
	 * logging attempts prior to console initialization.
	 *
	 * If there is already data queued for this port, send it prior to
	 * attempting to send any new data.
	 */
	if (pi->used)
		send_buffers(pi);

	spin_lock_irqsave(&consolelock, flags);

	/*
	 * If the internal_write() was passed a pointer to a
	 * viocharlpevent then we don't need to allocate a new one
	 * (this is the case where we are internal_writing user space
	 * data).  If we aren't writing user space data then we need
	 * to get an event from viopath.
	 */
	if (copy_needed) {
		/* This one is fetched from the viopath data structure */
		viochar = (struct viocharlpevent *)
			vio_get_event_buffer(viomajorsubtype_chario);
		/* Make sure we got a buffer */
		if (viochar == NULL) {
			spin_unlock_irqrestore(&consolelock, flags);
			hvlog("\n\rviocons: Can't get viochar buffer in internal_write().");
			return -EAGAIN;
		}
		initDataEvent(viochar, pi->lp);
	}

	curbuf = buf;
	bleft = len;

	while ((bleft > 0) && (pi->used == 0) &&
	       ((pi->seq - pi->ack) < VIOCHAR_WINDOW)) {
		if (bleft > VIOCHAR_MAX_DATA)
			curlen = VIOCHAR_MAX_DATA;
		else
			curlen = bleft;

		viochar->event.xCorrelationToken = pi->seq++;

		if (copy_needed) {
			memcpy(viochar->data, curbuf, curlen);
			viochar->len = curlen;
		}

		viochar->event.xSizeMinus1 =
		    offsetof(struct viocharlpevent, data) + curlen;

		hvrc = HvCallEvent_signalLpEvent(&viochar->event);
		if (hvrc) {
			spin_unlock_irqrestore(&consolelock, flags);
			if (copy_needed)
				vio_free_event_buffer(viomajorsubtype_chario, viochar);

			hvlog("viocons: error sending event! %d\n", (int)hvrc);
			return len - bleft;
		}

		curbuf += curlen;
		bleft -= curlen;
	}

	/* If we didn't send it all, buffer as much of it as we can. */
	if (bleft > 0)
		bleft -= buffer_add(pi, curbuf, bleft);
	/*
	 * Since we grabbed it from the viopath data structure, return
	 * it to the data structure.
	 */
	if (copy_needed)
		vio_free_event_buffer(viomajorsubtype_chario, viochar);
	spin_unlock_irqrestore(&consolelock, flags);

	return len - bleft;
}

static struct port_info *get_port_data(struct tty_struct *tty)
{
	unsigned long flags;
	struct port_info *pi;

	spin_lock_irqsave(&consolelock, flags);
	if (tty) {
		pi = (struct port_info *)tty->driver_data;
		if (!pi || viotty_paranoia_check(pi, tty->name,
					     "get_port_data")) {
			pi = NULL;
		}
	} else
		/*
		 * If this is the console device, use the lp from
		 * the first port entry
		 */
		pi = &port_info[0];
	spin_unlock_irqrestore(&consolelock, flags);
	return pi;
}

/*
 * Initialize the common fields in a charLpEvent
 */
static void initDataEvent(struct viocharlpevent *viochar, HvLpIndex lp)
{
	memset(viochar, 0, sizeof(struct viocharlpevent));

	viochar->event.xFlags.xValid = 1;
	viochar->event.xFlags.xFunction = HvLpEvent_Function_Int;
	viochar->event.xFlags.xAckInd = HvLpEvent_AckInd_NoAck;
	viochar->event.xFlags.xAckType = HvLpEvent_AckType_DeferredAck;
	viochar->event.xType = HvLpEvent_Type_VirtualIo;
	viochar->event.xSubtype = viomajorsubtype_chario | viochardata;
	viochar->event.xSourceLp = HvLpConfig_getLpIndex();
	viochar->event.xTargetLp = lp;
	viochar->event.xSizeMinus1 = sizeof(struct viocharlpevent);
	viochar->event.xSourceInstanceId = viopath_sourceinst(lp);
	viochar->event.xTargetInstanceId = viopath_targetinst(lp);
}

/*
 * early console device write
 */
static void viocons_write_early(struct console *co, const char *s, unsigned count)
{
	hvlogOutput(s, count);
}

/*
 * console device write
 */
static void viocons_write(struct console *co, const char *s, unsigned count)
{
	int index;
	int begin;
	struct port_info *pi;

	static const char cr = '\r';

	/*
	 * Check port data first because the target LP might be valid but
	 * simply not active, in which case we want to hvlog the output.
	 */
	pi = get_port_data(NULL);
	if (pi == NULL) {
		hvlog("\n\rviocons_write: unable to get port data.");
		return;
	}

	hvlogOutput(s, count);

	if (!viopath_isactive(pi->lp)) {
		/*
		 * This is a VERY noisy trace message in the case where the
		 * path manager is not active or in the case where this
		 * function is called prior to viocons initialization.  It is
		 * being commented out for the sake of a clear trace buffer.
		 */
#if 0
		 hvlog("\n\rviocons_write: path not active to lp %d", pi->lp);
#endif
		return;
	}

	/* 
	 * Any newline character found will cause a
	 * carriage return character to be emitted as well. 
	 */
	begin = 0;
	for (index = 0; index < count; index++) {
		if (s[index] == '\n') {
			/* 
			 * Newline found. Print everything up to and 
			 * including the newline
			 */
			internal_write(pi, &s[begin], index - begin + 1,
					NULL);
			begin = index + 1;
			/* Emit a carriage return as well */
			internal_write(pi, &cr, 1, NULL);
		}
	}

	/* If any characters left to write, write them now */
	if ((index - begin) > 0)
		internal_write(pi, &s[begin], index - begin, NULL);
}

/*
 * Work out the device associate with this console
 */
static struct tty_driver *viocons_device(struct console *c, int *index)
{
	*index = c->index;
	return viotty_driver;
}

/*
 * console device I/O methods
 */
static struct console viocons_early = {
	.name = "viocons",
	.write = viocons_write_early,
	.flags = CON_PRINTBUFFER,
	.index = -1,
};

static struct console viocons = {
	.name = "viocons",
	.write = viocons_write,
	.device = viocons_device,
	.flags = CON_PRINTBUFFER,
	.index = -1,
};

/*
 * TTY Open method
 */
static int viotty_open(struct tty_struct *tty, struct file *filp)
{
	int port;
	unsigned long flags;
	struct port_info *pi;

	port = tty->index;

	if ((port < 0) || (port >= VTTY_PORTS))
		return -ENODEV;

	spin_lock_irqsave(&consolelock, flags);

	pi = &port_info[port];
	/* If some other TTY is already connected here, reject the open */
	if ((pi->tty) && (pi->tty != tty)) {
		spin_unlock_irqrestore(&consolelock, flags);
		printk(VIOCONS_KERN_WARN
		       "attempt to open device twice from different ttys\n");
		return -EBUSY;
	}
	tty->driver_data = pi;
	pi->tty = tty;
	spin_unlock_irqrestore(&consolelock, flags);

	return 0;
}

/*
 * TTY Close method
 */
static void viotty_close(struct tty_struct *tty, struct file *filp)
{
	unsigned long flags;
	struct port_info *pi;

	spin_lock_irqsave(&consolelock, flags);
	pi = (struct port_info *)tty->driver_data;

	if (!pi || viotty_paranoia_check(pi, tty->name, "viotty_close")) {
		spin_unlock_irqrestore(&consolelock, flags);
		return;
	}
	if (tty->count == 1)
		pi->tty = NULL;
	spin_unlock_irqrestore(&consolelock, flags);
}

/*
 * TTY Write method
 */
static int viotty_write(struct tty_struct *tty, int from_user,
			const unsigned char *buf, int count)
{
	int ret;
	int total = 0;
	struct port_info *pi;

	pi = get_port_data(tty);
	if (pi == NULL) {
		hvlog("\n\rviotty_write: no port data.");
		return -ENODEV;
	}

	if (viochar_is_console(pi))
		hvlogOutput(buf, count);

	/*
	 * If the path to this LP is closed, don't bother doing anything more.
	 * just dump the data on the floor and return count.  For some reason
	 * some user level programs will attempt to probe available tty's and
	 * they'll attempt a viotty_write on an invalid port which maps to an
	 * invalid target lp.  If this is the case then ignore the
	 * viotty_write call and, since the viopath isn't active to this
	 * partition, return count.
	 */
	if (!viopath_isactive(pi->lp)) {
		/* Noisy trace.  Commented unless needed. */
#if 0
		 hvlog("\n\rviotty_write: viopath NOT active for lp %d.",pi->lp);
#endif
		return count;
	}

	/*
	 * If the viotty_write is invoked from user space we want to do the
	 * copy_from_user() into an event buffer from the cfu buffer before
	 * internal_write() is called because internal_write may need to buffer
	 * data which will need to grab a spin_lock and we shouldn't
	 * copy_from_user() while holding a spin_lock.  Should internal_write()
	 * not need to buffer data then it'll just use the event we created here
	 * rather than checking one out from vio_get_event_buffer().
	 */
	if (from_user) {
		struct viocharlpevent *viochar;
		int curlen;
		const char *curbuf = buf;

		viochar = viocons_get_cfu_buffer();
		if (viochar == NULL)
			return -EAGAIN;
		initDataEvent(viochar, pi->lp);
		while (count > 0) {
			if (count > VIOCHAR_MAX_DATA)
				curlen = VIOCHAR_MAX_DATA;
			else
				curlen = count;
			viochar->len = curlen;
			ret = copy_from_user(viochar->data, curbuf, curlen);
			if (ret)
				break;
			ret = internal_write(pi, viochar->data,
					viochar->len, viochar);
			total += ret;
			if (ret != curlen)
				break;
			count -= curlen;
			curbuf += curlen;
		}
		viocons_free_cfu_buffer(viochar);
	} else
		total = internal_write(pi, buf, count, NULL);
	return total;
}

/*
 * TTY put_char method
 */
static void viotty_put_char(struct tty_struct *tty, unsigned char ch)
{
	struct port_info *pi;

	pi = get_port_data(tty);
	if (pi == NULL)
		return;

	/* This will append '\r' as well if the char is '\n' */
	if (viochar_is_console(pi))
		hvlogOutput(&ch, 1);

	if (viopath_isactive(pi->lp))
		internal_write(pi, &ch, 1, NULL);
}

/*
 * TTY write_room method
 */
static int viotty_write_room(struct tty_struct *tty)
{
	int i;
	int room = 0;
	struct port_info *pi;
	unsigned long flags;

	spin_lock_irqsave(&consolelock, flags);
	pi = (struct port_info *)tty->driver_data;
	if (!pi || viotty_paranoia_check(pi, tty->name, "viotty_write_room")) {
		spin_unlock_irqrestore(&consolelock, flags);
		return 0;
	}

	/* If no buffers are used, return the max size. */
	if (pi->used == 0) {
		spin_unlock_irqrestore(&consolelock, flags);
		return VIOCHAR_MAX_DATA * VIOCHAR_NUM_BUF;
	}

	/*
	 * We retain the spinlock because we want to get an accurate
	 * count and it can change on us between each operation if we
	 * don't hold the spinlock.
	 */
	for (i = 0; ((i < VIOCHAR_NUM_BUF) && (room < VIOCHAR_MAX_DATA)); i++)
		room += (VIOCHAR_MAX_DATA - pi->bufferBytes[i]);
	spin_unlock_irqrestore(&consolelock, flags);

	if (room > VIOCHAR_MAX_DATA)
		room = VIOCHAR_MAX_DATA;
	return room;
}

/*
 * TTY chars_in_buffer method
 */
static int viotty_chars_in_buffer(struct tty_struct *tty)
{
	return 0;
}

static int viotty_ioctl(struct tty_struct *tty, struct file *file,
			unsigned int cmd, unsigned long arg)
{
	switch (cmd) {
	/*
	 * the ioctls below read/set the flags usually shown in the leds
	 * don't use them - they will go away without warning
	 */
	case KDGETLED:
	case KDGKBLED:
		return put_user(0, (char *)arg);

	case KDSKBLED:
		return 0;
	}

	return n_tty_ioctl(tty, file, cmd, arg);
}

/*
 * Handle an open charLpEvent.  Could be either interrupt or ack
 */
static void vioHandleOpenEvent(struct HvLpEvent *event)
{
	unsigned long flags;
	struct viocharlpevent *cevent = (struct viocharlpevent *)event;
	u8 port = cevent->virtual_device;
	struct port_info *pi;
	int reject = 0;