io.c

上传linux-jx2410的源代码

/* $Id: io.c,v 1.1.1.1 2004/02/04 12:55:32 laputa Exp $
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1992 - 1997, 2000 Silicon Graphics, Inc.
 * Copyright (C) 2000 by Colin Ngam
 */

#include <linux/types.h>
#include <linux/config.h>
#include <linux/slab.h>
#include <asm/sn/types.h>
#include <asm/sn/sgi.h>
#include <asm/sn/iobus.h>
#include <asm/sn/iograph.h>
#include <asm/param.h>
#include <asm/sn/pio.h>
#include <asm/sn/xtalk/xwidget.h>
#include <asm/sn/sn_private.h>
#include <asm/sn/addrs.h>
#include <asm/sn/invent.h>
#include <asm/sn/hcl.h>
#include <asm/sn/hcl_util.h>
#include <asm/sn/agent.h>
#include <asm/sn/intr.h>
#include <asm/sn/xtalk/xtalkaddrs.h>
#include <asm/sn/klconfig.h>
#include <asm/sn/io.h>
#include <asm/sn/sn_cpuid.h>

extern xtalk_provider_t hub_provider;

/*
 * Perform any initializations needed to support hub-based I/O.
 * Called once during startup.
 */
void
hubio_init(void)
{
#ifdef	LATER
	/* This isn't needed unless we port the entire sio driver ... */
        extern void early_brl1_port_init( void );
	early_brl1_port_init();
#endif
}

/* 
 * Implementation of hub iobus operations.
 *
 * Hub provides a crosstalk "iobus" on IP27 systems.  These routines
 * provide a platform-specific implementation of xtalk used by all xtalk 
 * cards on IP27 systems.
 *
 * Called from corresponding xtalk_* routines.
 */


/* PIO MANAGEMENT */
/* For mapping system virtual address space to xtalk space on a specified widget */

/*
 * Setup pio structures needed for a particular hub.
 */
static void
hub_pio_init(devfs_handle_t hubv)
{
	xwidgetnum_t widget;
	hubinfo_t hubinfo;
	nasid_t nasid;
	int bigwin;
	hub_piomap_t hub_piomap;

	hubinfo_get(hubv, &hubinfo);
	nasid = hubinfo->h_nasid;

	/* Initialize small window piomaps for this hub */
	for (widget=0; widget <= HUB_WIDGET_ID_MAX; widget++) {
		hub_piomap = hubinfo_swin_piomap_get(hubinfo, (int)widget);
		hub_piomap->hpio_xtalk_info.xp_target = widget;
		hub_piomap->hpio_xtalk_info.xp_xtalk_addr = 0;
		hub_piomap->hpio_xtalk_info.xp_mapsz = SWIN_SIZE;
		hub_piomap->hpio_xtalk_info.xp_kvaddr = (caddr_t)NODE_SWIN_BASE(nasid, widget);
		hub_piomap->hpio_hub = hubv;
		hub_piomap->hpio_flags = HUB_PIOMAP_IS_VALID;
	}

	/* Initialize big window piomaps for this hub */
	for (bigwin=0; bigwin < HUB_NUM_BIG_WINDOW; bigwin++) {
		hub_piomap = hubinfo_bwin_piomap_get(hubinfo, bigwin);
		hub_piomap->hpio_xtalk_info.xp_mapsz = BWIN_SIZE;
		hub_piomap->hpio_hub = hubv;
		hub_piomap->hpio_holdcnt = 0;
		hub_piomap->hpio_flags = HUB_PIOMAP_IS_BIGWINDOW;
		IIO_ITTE_DISABLE(nasid, bigwin);
	}
	hub_set_piomode(nasid, HUB_PIO_CONVEYOR);

	mutex_spinlock_init(&hubinfo->h_bwlock);
/*
 * If this lock can be acquired from interrupts or bh's, add SV_INTS or SV_BHS,
 * respectively, to the flags here.
 */
	sv_init(&hubinfo->h_bwwait, &hubinfo->h_bwlock, SV_ORDER_FIFO | SV_MON_SPIN); 
}

/* 
 * Create a caddr_t-to-xtalk_addr mapping.
 *
 * Use a small window if possible (that's the usual case), but
 * manage big windows if needed.  Big window mappings can be
 * either FIXED or UNFIXED -- we keep at least 1 big window available
 * for UNFIXED mappings.
 *
 * Returns an opaque pointer-sized type which can be passed to
 * other hub_pio_* routines on success, or NULL if the request
 * cannot be satisfied.
 */
/* ARGSUSED */
hub_piomap_t
hub_piomap_alloc(devfs_handle_t dev,	/* set up mapping for this device */
		device_desc_t dev_desc,	/* device descriptor */
		iopaddr_t xtalk_addr,	/* map for this xtalk_addr range */
		size_t byte_count,
		size_t byte_count_max, 	/* maximum size of a mapping */
		unsigned flags)		/* defined in sys/pio.h */
{
	xwidget_info_t widget_info = xwidget_info_get(dev);
	xwidgetnum_t widget = xwidget_info_id_get(widget_info);
	devfs_handle_t hubv = xwidget_info_master_get(widget_info);
	hubinfo_t hubinfo;
	hub_piomap_t bw_piomap;
	int bigwin, free_bw_index;
	nasid_t nasid;
	volatile hubreg_t junk;
	unsigned long s;

	/* sanity check */
	if (byte_count_max > byte_count)
		return(NULL);

	hubinfo_get(hubv, &hubinfo);

	/* If xtalk_addr range is mapped by a small window, we don't have 
	 * to do much 
	 */
	if (xtalk_addr + byte_count <= SWIN_SIZE)
		return(hubinfo_swin_piomap_get(hubinfo, (int)widget));

	/* We need to use a big window mapping.  */

	/*
	 * TBD: Allow requests that would consume multiple big windows --
	 * split the request up and use multiple mapping entries.
	 * For now, reject requests that span big windows.
	 */
	if ((xtalk_addr % BWIN_SIZE) + byte_count > BWIN_SIZE)
		return(NULL);


	/* Round xtalk address down for big window alignement */
	xtalk_addr = xtalk_addr & ~(BWIN_SIZE-1);

	/*
	 * Check to see if an existing big window mapping will suffice.
	 */
tryagain:
	free_bw_index = -1;
	s = mutex_spinlock(&hubinfo->h_bwlock);
	for (bigwin=0; bigwin < HUB_NUM_BIG_WINDOW; bigwin++) {
		bw_piomap = hubinfo_bwin_piomap_get(hubinfo, bigwin);

		/* If mapping is not valid, skip it */
		if (!(bw_piomap->hpio_flags & HUB_PIOMAP_IS_VALID)) {
			free_bw_index = bigwin;
			continue;
		}

		/* 
		 * If mapping is UNFIXED, skip it.  We don't allow sharing
		 * of UNFIXED mappings, because this would allow starvation.
		 */
		if (!(bw_piomap->hpio_flags & HUB_PIOMAP_IS_FIXED))
			continue;

		if ( xtalk_addr == bw_piomap->hpio_xtalk_info.xp_xtalk_addr &&
		     widget == bw_piomap->hpio_xtalk_info.xp_target) {
			bw_piomap->hpio_holdcnt++;
			mutex_spinunlock(&hubinfo->h_bwlock, s);
			return(bw_piomap);
		}
	}

	/*
	 * None of the existing big window mappings will work for us --
	 * we need to establish a new mapping.
	 */

	/* Insure that we don't consume all big windows with FIXED mappings */
	if (flags & PIOMAP_FIXED) {
		if (hubinfo->h_num_big_window_fixed < HUB_NUM_BIG_WINDOW-1) {
			ASSERT(free_bw_index >= 0);
			hubinfo->h_num_big_window_fixed++;
		} else {
			bw_piomap = NULL;
			goto done;
		}
	} else /* PIOMAP_UNFIXED */ {
		if (free_bw_index < 0) {
			if (flags & PIOMAP_NOSLEEP) {
				bw_piomap = NULL;
				goto done;
			}

			sv_wait(&hubinfo->h_bwwait, 0, 0);
			goto tryagain;
		}
	}


	/* OK!  Allocate big window free_bw_index for this mapping. */
 	/* 
	 * The code below does a PIO write to setup an ITTE entry.
	 * We need to prevent other CPUs from seeing our updated memory 
	 * shadow of the ITTE (in the piomap) until the ITTE entry is 
	 * actually set up; otherwise, another CPU might attempt a PIO 
	 * prematurely.  
	 *
	 * Also, the only way we can know that an entry has been received 
	 * by the hub and can be used by future PIO reads/writes is by 
	 * reading back the ITTE entry after writing it.
	 *
	 * For these two reasons, we PIO read back the ITTE entry after
	 * we write it.
	 */

	nasid = hubinfo->h_nasid;
	IIO_ITTE_PUT(nasid, free_bw_index, HUB_PIO_MAP_TO_MEM, widget, xtalk_addr);	
	junk = HUB_L(IIO_ITTE_GET(nasid, free_bw_index));

	bw_piomap = hubinfo_bwin_piomap_get(hubinfo, free_bw_index);
	bw_piomap->hpio_xtalk_info.xp_dev = dev;
	bw_piomap->hpio_xtalk_info.xp_target = widget;
	bw_piomap->hpio_xtalk_info.xp_xtalk_addr = xtalk_addr;
	bw_piomap->hpio_xtalk_info.xp_kvaddr = (caddr_t)NODE_BWIN_BASE(nasid, free_bw_index);
	bw_piomap->hpio_holdcnt++;
	bw_piomap->hpio_bigwin_num = free_bw_index;

	if (flags & PIOMAP_FIXED)
		bw_piomap->hpio_flags |= HUB_PIOMAP_IS_VALID | HUB_PIOMAP_IS_FIXED;
	else
		bw_piomap->hpio_flags |= HUB_PIOMAP_IS_VALID;

done:
	mutex_spinunlock(&hubinfo->h_bwlock, s);
	return(bw_piomap);
}

/*
 * hub_piomap_free destroys a caddr_t-to-xtalk pio mapping and frees
 * any associated mapping resources.  
 *
 * If this * piomap was handled with a small window, or if it was handled
 * in a big window that's still in use by someone else, then there's 
 * nothing to do.  On the other hand, if this mapping was handled 
 * with a big window, AND if we were the final user of that mapping, 
 * then destroy the mapping.
 */
void
hub_piomap_free(hub_piomap_t hub_piomap)
{
	devfs_handle_t hubv;
	hubinfo_t hubinfo;
	nasid_t nasid;
	unsigned long s;

	/* 
	 * Small windows are permanently mapped to corresponding widgets,
	 * so there're no resources to free.
	 */
	if (!(hub_piomap->hpio_flags & HUB_PIOMAP_IS_BIGWINDOW))
		return;

	ASSERT(hub_piomap->hpio_flags & HUB_PIOMAP_IS_VALID);
	ASSERT(hub_piomap->hpio_holdcnt > 0);

	hubv = hub_piomap->hpio_hub;
	hubinfo_get(hubv, &hubinfo);
	nasid = hubinfo->h_nasid;

	s = mutex_spinlock(&hubinfo->h_bwlock);

	/*
	 * If this is the last hold on this mapping, free it.
	 */
	if (--hub_piomap->hpio_holdcnt == 0) {
		IIO_ITTE_DISABLE(nasid, hub_piomap->hpio_bigwin_num );

		if (hub_piomap->hpio_flags & HUB_PIOMAP_IS_FIXED) {
			hub_piomap->hpio_flags &= ~(HUB_PIOMAP_IS_VALID | HUB_PIOMAP_IS_FIXED);
			hubinfo->h_num_big_window_fixed--;
			ASSERT(hubinfo->h_num_big_window_fixed >= 0);
		} else
			hub_piomap->hpio_flags &= ~HUB_PIOMAP_IS_VALID;

		(void)sv_signal(&hubinfo->h_bwwait);
	}

	mutex_spinunlock(&hubinfo->h_bwlock, s);
}

/*
 * Establish a mapping to a given xtalk address range using the resources
 * allocated earlier.
 */
caddr_t
hub_piomap_addr(hub_piomap_t hub_piomap,	/* mapping resources */
		iopaddr_t xtalk_addr,		/* map for this xtalk address */
		size_t byte_count)		/* map this many bytes */
{
	/* Verify that range can be mapped using the specified piomap */
	if (xtalk_addr < hub_piomap->hpio_xtalk_info.xp_xtalk_addr)
		return(0);

	if (xtalk_addr + byte_count > 
		( hub_piomap->hpio_xtalk_info.xp_xtalk_addr + 
			hub_piomap->hpio_xtalk_info.xp_mapsz))
		return(0);

	if (hub_piomap->hpio_flags & HUB_PIOMAP_IS_VALID)
		return(hub_piomap->hpio_xtalk_info.xp_kvaddr + 
			(xtalk_addr % hub_piomap->hpio_xtalk_info.xp_mapsz));
	else
		return(0);
}


/*
 * Driver indicates that it's done with PIO's from an earlier piomap_addr.
 */
/* ARGSUSED */
void
hub_piomap_done(hub_piomap_t hub_piomap)	/* done with these mapping resources */
{
	/* Nothing to do */
}


/*
 * For translations that require no mapping resources, supply a kernel virtual
 * address that maps to the specified xtalk address range.
 */
/* ARGSUSED */
caddr_t
hub_piotrans_addr(	devfs_handle_t dev,	/* translate to this device */
			device_desc_t dev_desc,	/* device descriptor */
			iopaddr_t xtalk_addr,	/* Crosstalk address */
			size_t byte_count,	/* map this many bytes */
			unsigned flags)		/* (currently unused) */
{
	xwidget_info_t widget_info = xwidget_info_get(dev);
	xwidgetnum_t widget = xwidget_info_id_get(widget_info);
	devfs_handle_t hubv = xwidget_info_master_get(widget_info);
	hub_piomap_t hub_piomap;
	hubinfo_t hubinfo;

	hubinfo_get(hubv, &hubinfo);

	if (xtalk_addr + byte_count <= SWIN_SIZE) {
		hub_piomap = hubinfo_swin_piomap_get(hubinfo, (int)widget);
		return(hub_piomap_addr(hub_piomap, xtalk_addr, byte_count));
	} else
		return(0);
}


/* DMA MANAGEMENT */
/* Mapping from crosstalk space to system physical space */

/* 
 * There's not really very much to do here, since crosstalk maps
 * directly to system physical space.  It's quite possible that this
 * DMA layer will be bypassed in performance kernels.
 */


/* ARGSUSED */
static void
hub_dma_init(devfs_handle_t hubv)
{
}


/*
 * Allocate resources needed to set up DMA mappings up to a specified size
 * on a specified adapter.
 * 
 * We don't actually use the adapter ID for anything.  It's just the adapter
 * that the lower level driver plans to use for DMA.
 */
/* ARGSUSED */
hub_dmamap_t
hub_dmamap_alloc(	devfs_handle_t dev,	/* set up mappings for this device */
			device_desc_t dev_desc,	/* device descriptor */
			size_t byte_count_max, 	/* max size of a mapping */
			unsigned flags)		/* defined in dma.h */
{
	hub_dmamap_t dmamap;
	xwidget_info_t widget_info = xwidget_info_get(dev);
	xwidgetnum_t widget = xwidget_info_id_get(widget_info);
	devfs_handle_t hubv = xwidget_info_master_get(widget_info);

	dmamap = kern_malloc(sizeof(struct hub_dmamap_s));
	dmamap->hdma_xtalk_info.xd_dev = dev;
	dmamap->hdma_xtalk_info.xd_target = widget;
	dmamap->hdma_hub = hubv;
	dmamap->hdma_flags = HUB_DMAMAP_IS_VALID;
 	if (flags & XTALK_FIXED)
		dmamap->hdma_flags |= HUB_DMAMAP_IS_FIXED;

	return(dmamap);
}

/*
 * Destroy a DMA mapping from crosstalk space to system address space.
 * There is no actual mapping hardware to destroy, but we at least mark
 * the dmamap INVALID and free the space that it took.
 */
void
hub_dmamap_free(hub_dmamap_t hub_dmamap)
{
	hub_dmamap->hdma_flags &= ~HUB_DMAMAP_IS_VALID;
	kern_free(hub_dmamap);
}

/*
 * Establish a DMA mapping using the resources allocated in a previous dmamap_alloc.
 * Return an appropriate crosstalk address range that maps to the specified physical