/**
* hub_pio_map - establish a HUB PIO mapping
*
* @hub: hub to perform PIO mapping on
* @widget: widget ID to perform PIO mapping for
* @xtalk_addr: xtalk_address that needs to be mapped
* @size: size of the PIO mapping
*
**/
unsigned long hub_pio_map(cnodeid_t cnode, xwidgetnum_t widget,
unsigned long xtalk_addr, size_t size)
{
nasid_t nasid = COMPACT_TO_NASID_NODEID(cnode);
volatile hubreg_t junk;
unsigned i;
/* use small-window mapping if possible */
if ((xtalk_addr % SWIN_SIZE) + size <= SWIN_SIZE)
return NODE_SWIN_BASE(nasid, widget) + (xtalk_addr % SWIN_SIZE);
if ((xtalk_addr % BWIN_SIZE) + size > BWIN_SIZE) {
printk(KERN_WARNING "PIO mapping at hub %d widget %d addr 0x%lx"
" too big (%ld)\n",
nasid, widget, xtalk_addr, size);
return 0;
}
xtalk_addr &= ~(BWIN_SIZE-1);
for (i = 0; i < HUB_NUM_BIG_WINDOW; i++) {
if (test_and_set_bit(i, hub_data(cnode)->h_bigwin_used))
continue;
/*
* 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.
*/
IIO_ITTE_PUT(nasid, i, HUB_PIO_MAP_TO_MEM, widget, xtalk_addr);
junk = HUB_L(IIO_ITTE_GET(nasid, i));
return NODE_BWIN_BASE(nasid, widget) + (xtalk_addr % BWIN_SIZE);
}
printk(KERN_WARNING "unable to establish PIO mapping for at"
" hub %d widget %d addr 0x%lx\n",
nasid, widget, xtalk_addr);
return 0;
}
/* 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;
int 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, PZERO, &hubinfo->h_bwlock, s);
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);
}