viocons.c

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

/* -*- linux-c -*-
 *
 *  drivers/char/viocons.c
 *
 *  iSeries Virtual Terminal
 *
 *  Authors: Dave Boutcher <[e-mail]>
 *           Ryan Arnold <[e-mail]>
 *           Colin Devilbiss <[e-mail]>
 *           Stephen Rothwell <[e-mail]>
 *
 * (C) Copyright 2000, 2001, 2002, 2003, 2004 IBM Corporation
 *
 * This program is free software;  you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) anyu later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#include <linux/config.h>
#include <linux/version.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/errno.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/console.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <asm/ioctls.h>
#include <linux/kd.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/sysrq.h>

#include <asm/iSeries/vio.h>

#include <asm/iSeries/HvLpEvent.h>
#include <asm/iSeries/HvCallEvent.h>
#include <asm/iSeries/HvLpConfig.h>
#include <asm/iSeries/HvCall.h>

#ifdef CONFIG_VT
#error You must turn off CONFIG_VT to use CONFIG_VIOCONS
#endif

#define VIOTTY_MAGIC (0x0DCB)
#define VTTY_PORTS 10

#define VIOCONS_KERN_WARN	KERN_WARNING "viocons: "
#define VIOCONS_KERN_INFO	KERN_INFO "viocons: "

static spinlock_t consolelock = SPIN_LOCK_UNLOCKED;
static spinlock_t consoleloglock = SPIN_LOCK_UNLOCKED;

#ifdef CONFIG_MAGIC_SYSRQ
static int vio_sysrq_pressed;
extern int sysrq_enabled;
#endif

/*
 * The structure of the events that flow between us and OS/400.  You can't
 * mess with this unless the OS/400 side changes too
 */
struct viocharlpevent {
	struct HvLpEvent event;
	u32 reserved;
	u16 version;
	u16 subtype_result_code;
	u8 virtual_device;
	u8 len;
	u8 data[VIOCHAR_MAX_DATA];
};

/*
 * This is a place where we handle the distribution of memory
 * for copy_from_user() calls.  The buffer_available array is to
 * help us determine which buffer to use.
 */
#define VIOCHAR_NUM_CFU_BUFFERS	7
static struct viocharlpevent viocons_cfu_buffer[VIOCHAR_NUM_CFU_BUFFERS];
static atomic_t viocons_cfu_buffer_available[VIOCHAR_NUM_CFU_BUFFERS];

#define VIOCHAR_WINDOW		10
#define VIOCHAR_HIGHWATERMARK	3

enum viocharsubtype {
	viocharopen = 0x0001,
	viocharclose = 0x0002,
	viochardata = 0x0003,
	viocharack = 0x0004,
	viocharconfig = 0x0005
};

enum viochar_rc {
	viochar_rc_ebusy = 1
};

#define VIOCHAR_NUM_BUF		16

/*
 * Our port information.  We store a pointer to one entry in the
 * tty_driver_data
 */
static struct port_info {
	int magic;
	struct tty_struct *tty;
	HvLpIndex lp;
	u8 vcons;
	u64 seq;	/* sequence number of last HV send */
	u64 ack;	/* last ack from HV */
/*
 * When we get writes faster than we can send it to the partition,
 * buffer the data here. Note that used is a bit map of used buffers.
 * It had better have enough bits to hold VIOCHAR_NUM_BUF the bitops assume
 * it is a multiple of unsigned long
 */
	unsigned long used;
	u8 *buffer[VIOCHAR_NUM_BUF];
	int bufferBytes[VIOCHAR_NUM_BUF];
	int curbuf;
	int bufferOverflow;
	int overflowMessage;
} port_info[VTTY_PORTS];

#define viochar_is_console(pi)	((pi) == &port_info[0])
#define viochar_port(pi)	((pi) - &port_info[0])

static void initDataEvent(struct viocharlpevent *viochar, HvLpIndex lp);

static struct tty_driver *viotty_driver;

void hvlog(char *fmt, ...)
{
	int i;
	unsigned long flags;
	va_list args;
	static char buf[256];

	spin_lock_irqsave(&consoleloglock, flags);
	va_start(args, fmt);
	i = vscnprintf(buf, sizeof(buf) - 1, fmt, args);
	va_end(args);
	buf[i++] = '\r';
	HvCall_writeLogBuffer(buf, i);
	spin_unlock_irqrestore(&consoleloglock, flags);
}

void hvlogOutput(const char *buf, int count)
{
	unsigned long flags;
	int begin;
	int index;
	static const char cr = '\r';

	begin = 0;
	spin_lock_irqsave(&consoleloglock, flags);
	for (index = 0; index < count; index++) {
		if (buf[index] == '\n') {
			/*
			 * Start right after the last '\n' or at the zeroth
			 * array position and output the number of characters
			 * including the newline.
			 */
			HvCall_writeLogBuffer(&buf[begin], index - begin + 1);
			begin = index + 1;
			HvCall_writeLogBuffer(&cr, 1);
		}
	}
	if ((index - begin) > 0)
		HvCall_writeLogBuffer(&buf[begin], index - begin);
	spin_unlock_irqrestore(&consoleloglock, flags);
}

/*
 * Make sure we're pointing to a valid port_info structure.  Shamelessly
 * plagerized from serial.c
 */
static inline int viotty_paranoia_check(struct port_info *pi,
					char *name, const char *routine)
{
	static const char *bad_pi_addr = VIOCONS_KERN_WARN
		"warning: bad address for port_info struct (%s) in %s\n";
	static const char *badmagic = VIOCONS_KERN_WARN
		"warning: bad magic number for port_info struct (%s) in %s\n";

	if ((pi < &port_info[0]) || (viochar_port(pi) > VTTY_PORTS)) {
		printk(bad_pi_addr, name, routine);
		return 1;
	}
	if (pi->magic != VIOTTY_MAGIC) {
		printk(badmagic, name, routine);
		return 1;
	}
	return 0;
}

/*
 * This function should ONLY be called once from viocons_init2
 */
static void viocons_init_cfu_buffer(void)
{
	int i;

	for (i = 1; i < VIOCHAR_NUM_CFU_BUFFERS; i++)
		atomic_set(&viocons_cfu_buffer_available[i], 1);
}

static struct viocharlpevent *viocons_get_cfu_buffer(void)
{
	int i;

	/*
	 * Grab the first available buffer.  It doesn't matter if we
	 * are interrupted during this array traversal as long as we
	 * get an available space.
	 */
	for (i = 0; i < VIOCHAR_NUM_CFU_BUFFERS; i++)
		if (atomic_dec_if_positive(&viocons_cfu_buffer_available[i])
				== 0 )
			return &viocons_cfu_buffer[i];
	hvlog("\n\rviocons: viocons_get_cfu_buffer : no free buffers found");
	return NULL;
}

static void viocons_free_cfu_buffer(struct viocharlpevent *buffer)
{
	int i;

	i = buffer - &viocons_cfu_buffer[0];
	if (i >= (sizeof(viocons_cfu_buffer) / sizeof(viocons_cfu_buffer[0]))) {
		hvlog("\n\rviocons: viocons_free_cfu_buffer : buffer pointer not found in list.");
		return;
	}
	if (atomic_read(&viocons_cfu_buffer_available[i]) != 0) {
		hvlog("\n\rviocons: WARNING : returning unallocated cfu buffer.");
		return;
	}
	atomic_set(&viocons_cfu_buffer_available[i], 1);
}

/*
 * Add data to our pending-send buffers.  
 *
 * NOTE: Don't use printk in here because it gets nastily recursive.
 * hvlog can be used to log to the hypervisor buffer
 */
static int buffer_add(struct port_info *pi, const char *buf, size_t len)
{
	size_t bleft;
	size_t curlen;
	const char *curbuf;
	int nextbuf;

	curbuf = buf;
	bleft = len;
	while (bleft > 0) {
		/*
		 * If there is no space left in the current buffer, we have
		 * filled everything up, so return.  If we filled the previous
		 * buffer we would already have moved to the next one.
		 */
		if (pi->bufferBytes[pi->curbuf] == VIOCHAR_MAX_DATA) {
			hvlog ("\n\rviocons: No overflow buffer available for memcpy().\n");
			pi->bufferOverflow++;
			pi->overflowMessage = 1;
			break;
		}

		/*
		 * Turn on the "used" bit for this buffer.  If it's already on,
		 * that's fine.
		 */
		set_bit(pi->curbuf, &pi->used);

		/*
		 * See if this buffer has been allocated.  If not, allocate it.
		 */
		if (pi->buffer[pi->curbuf] == NULL) {
			pi->buffer[pi->curbuf] =
			    kmalloc(VIOCHAR_MAX_DATA, GFP_ATOMIC);
			if (pi->buffer[pi->curbuf] == NULL) {
				hvlog("\n\rviocons: kmalloc failed allocating spaces for buffer %d.",
					pi->curbuf);
				break;
			}
		}

		/* Figure out how much we can copy into this buffer. */
		if (bleft < (VIOCHAR_MAX_DATA - pi->bufferBytes[pi->curbuf]))
			curlen = bleft;
		else
			curlen = VIOCHAR_MAX_DATA - pi->bufferBytes[pi->curbuf];

		/* Copy the data into the buffer. */
		memcpy(pi->buffer[pi->curbuf] + pi->bufferBytes[pi->curbuf],
				curbuf, curlen);

		pi->bufferBytes[pi->curbuf] += curlen;
		curbuf += curlen;
		bleft -= curlen;

		/*
		 * Now see if we've filled this buffer.  If not then
		 * we'll try to use it again later.  If we've filled it
		 * up then we'll advance the curbuf to the next in the
		 * circular queue.
		 */
		if (pi->bufferBytes[pi->curbuf] == VIOCHAR_MAX_DATA) {
			nextbuf = (pi->curbuf + 1) % VIOCHAR_NUM_BUF;
			/*
			 * Move to the next buffer if it hasn't been used yet
			 */
			if (test_bit(nextbuf, &pi->used) == 0)
				pi->curbuf = nextbuf;
		}
	}
	return len - bleft;
}

/*
 * Send pending data
 *
 * NOTE: Don't use printk in here because it gets nastily recursive.
 * hvlog can be used to log to the hypervisor buffer
 */
static void send_buffers(struct port_info *pi)
{
	HvLpEvent_Rc hvrc;
	int nextbuf;
	struct viocharlpevent *viochar;
	unsigned long flags;

	spin_lock_irqsave(&consolelock, flags);

	viochar = (struct viocharlpevent *)
	    vio_get_event_buffer(viomajorsubtype_chario);

	/* Make sure we got a buffer */
	if (viochar == NULL) {
		hvlog("\n\rviocons: Can't get viochar buffer in sendBuffers().");
		spin_unlock_irqrestore(&consolelock, flags);
		return;
	}

	if (pi->used == 0) {
		hvlog("\n\rviocons: in sendbuffers(), but no buffers used.\n");
		vio_free_event_buffer(viomajorsubtype_chario, viochar);
		spin_unlock_irqrestore(&consolelock, flags);
		return;
	}

	/*
	 * curbuf points to the buffer we're filling.  We want to
	 * start sending AFTER this one.  
	 */
	nextbuf = (pi->curbuf + 1) % VIOCHAR_NUM_BUF;

	/*
	 * Loop until we find a buffer with the used bit on
	 */
	while (test_bit(nextbuf, &pi->used) == 0)
		nextbuf = (nextbuf + 1) % VIOCHAR_NUM_BUF;

	initDataEvent(viochar, pi->lp);

	/*
	 * While we have buffers with data, and our send window
	 * is open, send them
	 */
	while ((test_bit(nextbuf, &pi->used)) &&
	       ((pi->seq - pi->ack) < VIOCHAR_WINDOW)) {
		viochar->len = pi->bufferBytes[nextbuf];
		viochar->event.xCorrelationToken = pi->seq++;
		viochar->event.xSizeMinus1 =
			offsetof(struct viocharlpevent, data) + viochar->len;

		memcpy(viochar->data, pi->buffer[nextbuf], viochar->len);

		hvrc = HvCallEvent_signalLpEvent(&viochar->event);
		if (hvrc) {
			/*
			 * MUST unlock the spinlock before doing a printk
			 */
			vio_free_event_buffer(viomajorsubtype_chario, viochar);
			spin_unlock_irqrestore(&consolelock, flags);

			printk(VIOCONS_KERN_WARN
			       "error sending event! return code %d\n",
			       (int)hvrc);
			return;
		}

		/*
		 * clear the used bit, zero the number of bytes in
		 * this buffer, and move to the next buffer
		 */
		clear_bit(nextbuf, &pi->used);
		pi->bufferBytes[nextbuf] = 0;
		nextbuf = (nextbuf + 1) % VIOCHAR_NUM_BUF;
	}

	/*
	 * If we have emptied all the buffers, start at 0 again.
	 * this will re-use any allocated buffers
	 */
	if (pi->used == 0) {
		pi->curbuf = 0;

		if (pi->overflowMessage)
			pi->overflowMessage = 0;

		if (pi->tty) {
			tty_wakeup(pi->tty);
		}
	}

	vio_free_event_buffer(viomajorsubtype_chario, viochar);
	spin_unlock_irqrestore(&consolelock, flags);
}

/*
 * Our internal writer.  Gets called both from the console device and
 * the tty device.  the tty pointer will be NULL if called from the console.
 * Return total number of bytes "written".
 *
 * NOTE: Don't use printk in here because it gets nastily recursive.  hvlog
 * can be used to log to the hypervisor buffer
 */
static int internal_write(struct port_info *pi, const char *buf,
			  size_t len, struct viocharlpevent *viochar)
{
	HvLpEvent_Rc hvrc;
	size_t bleft;