viopath.c

linux-2.6.15.6

/* -*- linux-c -*-
 *
 *  iSeries Virtual I/O Message Path code
 *
 *  Authors: Dave Boutcher <[e-mail]>
 *           Ryan Arnold <[e-mail]>
 *           Colin Devilbiss <[e-mail]>
 *
 * (C) Copyright 2000-2005 IBM Corporation
 *
 * This code is used by the iSeries virtual disk, cd,
 * tape, and console to communicate with OS/400 in another
 * partition.
 *
 * 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/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/vmalloc.h>
#include <linux/string.h>
#include <linux/proc_fs.h>
#include <linux/dma-mapping.h>
#include <linux/wait.h>
#include <linux/seq_file.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h>

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/iseries/hv_types.h>
#include <asm/iseries/it_exp_vpd_panel.h>
#include <asm/iseries/hv_lp_event.h>
#include <asm/iseries/hv_lp_config.h>
#include <asm/iseries/mf.h>
#include <asm/iseries/vio.h>

/* Status of the path to each other partition in the system.
 * This is overkill, since we will only ever establish connections
 * to our hosting partition and the primary partition on the system.
 * But this allows for other support in the future.
 */
static struct viopathStatus {
	int isOpen;		/* Did we open the path?            */
	int isActive;		/* Do we have a mon msg outstanding */
	int users[VIO_MAX_SUBTYPES];
	HvLpInstanceId mSourceInst;
	HvLpInstanceId mTargetInst;
	int numberAllocated;
} viopathStatus[HVMAXARCHITECTEDLPS];

static DEFINE_SPINLOCK(statuslock);

/*
 * For each kind of event we allocate a buffer that is
 * guaranteed not to cross a page boundary
 */
static unsigned char event_buffer[VIO_MAX_SUBTYPES * 256]
	__attribute__((__aligned__(4096)));
static atomic_t event_buffer_available[VIO_MAX_SUBTYPES];
static int event_buffer_initialised;

static void handleMonitorEvent(struct HvLpEvent *event);

/*
 * We use this structure to handle asynchronous responses.  The caller
 * blocks on the semaphore and the handler posts the semaphore.  However,
 * if system_state is not SYSTEM_RUNNING, then wait_atomic is used ...
 */
struct alloc_parms {
	struct semaphore sem;
	int number;
	atomic_t wait_atomic;
	int used_wait_atomic;
};

/* Put a sequence number in each mon msg.  The value is not
 * important.  Start at something other than 0 just for
 * readability.  wrapping this is ok.
 */
static u8 viomonseq = 22;

/* Our hosting logical partition.  We get this at startup
 * time, and different modules access this variable directly.
 */
HvLpIndex viopath_hostLp = HvLpIndexInvalid;
EXPORT_SYMBOL(viopath_hostLp);
HvLpIndex viopath_ourLp = HvLpIndexInvalid;
EXPORT_SYMBOL(viopath_ourLp);

/* For each kind of incoming event we set a pointer to a
 * routine to call.
 */
static vio_event_handler_t *vio_handler[VIO_MAX_SUBTYPES];

#define VIOPATH_KERN_WARN	KERN_WARNING "viopath: "
#define VIOPATH_KERN_INFO	KERN_INFO "viopath: "

static int proc_viopath_show(struct seq_file *m, void *v)
{
	char *buf;
	u16 vlanMap;
	dma_addr_t handle;
	HvLpEvent_Rc hvrc;
	DECLARE_MUTEX_LOCKED(Semaphore);

	buf = kmalloc(HW_PAGE_SIZE, GFP_KERNEL);
	if (!buf)
		return 0;
	memset(buf, 0, HW_PAGE_SIZE);

	handle = dma_map_single(iSeries_vio_dev, buf, HW_PAGE_SIZE,
				DMA_FROM_DEVICE);

	hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
			HvLpEvent_Type_VirtualIo,
			viomajorsubtype_config | vioconfigget,
			HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
			viopath_sourceinst(viopath_hostLp),
			viopath_targetinst(viopath_hostLp),
			(u64)(unsigned long)&Semaphore, VIOVERSION << 16,
			((u64)handle) << 32, HW_PAGE_SIZE, 0, 0);

	if (hvrc != HvLpEvent_Rc_Good)
		printk(VIOPATH_KERN_WARN "hv error on op %d\n", (int)hvrc);

	down(&Semaphore);

	vlanMap = HvLpConfig_getVirtualLanIndexMap();

	buf[HW_PAGE_SIZE-1] = '\0';
	seq_printf(m, "%s", buf);
	seq_printf(m, "AVAILABLE_VETH=%x\n", vlanMap);
	seq_printf(m, "SRLNBR=%c%c%c%c%c%c%c\n",
		   e2a(xItExtVpdPanel.mfgID[2]),
		   e2a(xItExtVpdPanel.mfgID[3]),
		   e2a(xItExtVpdPanel.systemSerial[1]),
		   e2a(xItExtVpdPanel.systemSerial[2]),
		   e2a(xItExtVpdPanel.systemSerial[3]),
		   e2a(xItExtVpdPanel.systemSerial[4]),
		   e2a(xItExtVpdPanel.systemSerial[5]));

	dma_unmap_single(iSeries_vio_dev, handle, HW_PAGE_SIZE,
			 DMA_FROM_DEVICE);
	kfree(buf);

	return 0;
}

static int proc_viopath_open(struct inode *inode, struct file *file)
{
	return single_open(file, proc_viopath_show, NULL);
}

static struct file_operations proc_viopath_operations = {
	.open		= proc_viopath_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static int __init vio_proc_init(void)
{
	struct proc_dir_entry *e;

	e = create_proc_entry("iSeries/config", 0, NULL);
	if (e)
		e->proc_fops = &proc_viopath_operations;

        return 0;
}
__initcall(vio_proc_init);

/* See if a given LP is active.  Allow for invalid lps to be passed in
 * and just return invalid
 */
int viopath_isactive(HvLpIndex lp)
{
	if (lp == HvLpIndexInvalid)
		return 0;
	if (lp < HVMAXARCHITECTEDLPS)
		return viopathStatus[lp].isActive;
	else
		return 0;
}
EXPORT_SYMBOL(viopath_isactive);

/*
 * We cache the source and target instance ids for each
 * partition.
 */
HvLpInstanceId viopath_sourceinst(HvLpIndex lp)
{
	return viopathStatus[lp].mSourceInst;
}
EXPORT_SYMBOL(viopath_sourceinst);

HvLpInstanceId viopath_targetinst(HvLpIndex lp)
{
	return viopathStatus[lp].mTargetInst;
}
EXPORT_SYMBOL(viopath_targetinst);

/*
 * Send a monitor message.  This is a message with the acknowledge
 * bit on that the other side will NOT explicitly acknowledge.  When
 * the other side goes down, the hypervisor will acknowledge any
 * outstanding messages....so we will know when the other side dies.
 */
static void sendMonMsg(HvLpIndex remoteLp)
{
	HvLpEvent_Rc hvrc;

	viopathStatus[remoteLp].mSourceInst =
		HvCallEvent_getSourceLpInstanceId(remoteLp,
				HvLpEvent_Type_VirtualIo);
	viopathStatus[remoteLp].mTargetInst =
		HvCallEvent_getTargetLpInstanceId(remoteLp,
				HvLpEvent_Type_VirtualIo);

	/*
	 * Deliberately ignore the return code here.  if we call this
	 * more than once, we don't care.
	 */
	vio_setHandler(viomajorsubtype_monitor, handleMonitorEvent);

	hvrc = HvCallEvent_signalLpEventFast(remoteLp, HvLpEvent_Type_VirtualIo,
			viomajorsubtype_monitor, HvLpEvent_AckInd_DoAck,
			HvLpEvent_AckType_DeferredAck,
			viopathStatus[remoteLp].mSourceInst,
			viopathStatus[remoteLp].mTargetInst,
			viomonseq++, 0, 0, 0, 0, 0);

	if (hvrc == HvLpEvent_Rc_Good)
		viopathStatus[remoteLp].isActive = 1;
	else {
		printk(VIOPATH_KERN_WARN "could not connect to partition %d\n",
				remoteLp);
		viopathStatus[remoteLp].isActive = 0;
	}
}

static void handleMonitorEvent(struct HvLpEvent *event)
{
	HvLpIndex remoteLp;
	int i;

	/*
	 * This handler is _also_ called as part of the loop
	 * at the end of this routine, so it must be able to
	 * ignore NULL events...
	 */
	if (!event)
		return;

	/*
	 * First see if this is just a normal monitor message from the
	 * other partition
	 */
	if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
		remoteLp = event->xSourceLp;
		if (!viopathStatus[remoteLp].isActive)
			sendMonMsg(remoteLp);
		return;
	}

	/*
	 * This path is for an acknowledgement; the other partition
	 * died
	 */
	remoteLp = event->xTargetLp;
	if ((event->xSourceInstanceId != viopathStatus[remoteLp].mSourceInst) ||
	    (event->xTargetInstanceId != viopathStatus[remoteLp].mTargetInst)) {
		printk(VIOPATH_KERN_WARN "ignoring ack....mismatched instances\n");
		return;
	}

	printk(VIOPATH_KERN_WARN "partition %d ended\n", remoteLp);

	viopathStatus[remoteLp].isActive = 0;

	/*
	 * For each active handler, pass them a NULL
	 * message to indicate that the other partition
	 * died
	 */
	for (i = 0; i < VIO_MAX_SUBTYPES; i++) {
		if (vio_handler[i] != NULL)
			(*vio_handler[i])(NULL);
	}
}

int vio_setHandler(int subtype, vio_event_handler_t *beh)
{
	subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
	if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
		return -EINVAL;
	if (vio_handler[subtype] != NULL)
		return -EBUSY;
	vio_handler[subtype] = beh;
	return 0;
}
EXPORT_SYMBOL(vio_setHandler);

int vio_clearHandler(int subtype)
{
	subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
	if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
		return -EINVAL;
	if (vio_handler[subtype] == NULL)
		return -EAGAIN;
	vio_handler[subtype] = NULL;
	return 0;
}
EXPORT_SYMBOL(vio_clearHandler);

static void handleConfig(struct HvLpEvent *event)
{
	if (!event)
		return;
	if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
		printk(VIOPATH_KERN_WARN
		       "unexpected config request from partition %d",
		       event->xSourceLp);