linux/drivers/ssb/sprom.c
John W. Linville d53cdbb94a ssb: do not read SPROM if it does not exist
Attempting to read registers that don't exist on the SSB bus can cause
hangs on some boxes.  At least some b43 devices are 'in the wild' that
don't have SPROMs at all.  When the SSB bus support loads, it attempts
to read these (non-existant) SPROMs and causes hard hangs on the box --
no console output, etc.

This patch adds some intelligence to determine whether or not the SPROM
is present before attempting to read it.  This avoids those hard hangs
on those devices with no SPROM attached to their SSB bus.  The
SSB-attached devices (e.g. b43, et al.) won't work, but at least the box
will survive to test further patches. :-)

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Michael Buesch <mb@bu3sch.de>
2010-04-26 13:50:54 -04:00

192 lines
4.9 KiB
C

/*
* Sonics Silicon Backplane
* Common SPROM support routines
*
* Copyright (C) 2005-2008 Michael Buesch <mb@bu3sch.de>
* Copyright (C) 2005 Martin Langer <martin-langer@gmx.de>
* Copyright (C) 2005 Stefano Brivio <st3@riseup.net>
* Copyright (C) 2005 Danny van Dyk <kugelfang@gentoo.org>
* Copyright (C) 2005 Andreas Jaggi <andreas.jaggi@waterwave.ch>
*
* Licensed under the GNU/GPL. See COPYING for details.
*/
#include "ssb_private.h"
#include <linux/ctype.h>
static const struct ssb_sprom *fallback_sprom;
static int sprom2hex(const u16 *sprom, char *buf, size_t buf_len,
size_t sprom_size_words)
{
int i, pos = 0;
for (i = 0; i < sprom_size_words; i++)
pos += snprintf(buf + pos, buf_len - pos - 1,
"%04X", swab16(sprom[i]) & 0xFFFF);
pos += snprintf(buf + pos, buf_len - pos - 1, "\n");
return pos + 1;
}
static int hex2sprom(u16 *sprom, const char *dump, size_t len,
size_t sprom_size_words)
{
char c, tmp[5] = { 0 };
int err, cnt = 0;
unsigned long parsed;
/* Strip whitespace at the end. */
while (len) {
c = dump[len - 1];
if (!isspace(c) && c != '\0')
break;
len--;
}
/* Length must match exactly. */
if (len != sprom_size_words * 4)
return -EINVAL;
while (cnt < sprom_size_words) {
memcpy(tmp, dump, 4);
dump += 4;
err = strict_strtoul(tmp, 16, &parsed);
if (err)
return err;
sprom[cnt++] = swab16((u16)parsed);
}
return 0;
}
/* Common sprom device-attribute show-handler */
ssize_t ssb_attr_sprom_show(struct ssb_bus *bus, char *buf,
int (*sprom_read)(struct ssb_bus *bus, u16 *sprom))
{
u16 *sprom;
int err = -ENOMEM;
ssize_t count = 0;
size_t sprom_size_words = bus->sprom_size;
sprom = kcalloc(sprom_size_words, sizeof(u16), GFP_KERNEL);
if (!sprom)
goto out;
/* Use interruptible locking, as the SPROM write might
* be holding the lock for several seconds. So allow userspace
* to cancel operation. */
err = -ERESTARTSYS;
if (mutex_lock_interruptible(&bus->sprom_mutex))
goto out_kfree;
err = sprom_read(bus, sprom);
mutex_unlock(&bus->sprom_mutex);
if (!err)
count = sprom2hex(sprom, buf, PAGE_SIZE, sprom_size_words);
out_kfree:
kfree(sprom);
out:
return err ? err : count;
}
/* Common sprom device-attribute store-handler */
ssize_t ssb_attr_sprom_store(struct ssb_bus *bus,
const char *buf, size_t count,
int (*sprom_check_crc)(const u16 *sprom, size_t size),
int (*sprom_write)(struct ssb_bus *bus, const u16 *sprom))
{
u16 *sprom;
int res = 0, err = -ENOMEM;
size_t sprom_size_words = bus->sprom_size;
struct ssb_freeze_context freeze;
sprom = kcalloc(bus->sprom_size, sizeof(u16), GFP_KERNEL);
if (!sprom)
goto out;
err = hex2sprom(sprom, buf, count, sprom_size_words);
if (err) {
err = -EINVAL;
goto out_kfree;
}
err = sprom_check_crc(sprom, sprom_size_words);
if (err) {
err = -EINVAL;
goto out_kfree;
}
/* Use interruptible locking, as the SPROM write might
* be holding the lock for several seconds. So allow userspace
* to cancel operation. */
err = -ERESTARTSYS;
if (mutex_lock_interruptible(&bus->sprom_mutex))
goto out_kfree;
err = ssb_devices_freeze(bus, &freeze);
if (err) {
ssb_printk(KERN_ERR PFX "SPROM write: Could not freeze all devices\n");
goto out_unlock;
}
res = sprom_write(bus, sprom);
err = ssb_devices_thaw(&freeze);
if (err)
ssb_printk(KERN_ERR PFX "SPROM write: Could not thaw all devices\n");
out_unlock:
mutex_unlock(&bus->sprom_mutex);
out_kfree:
kfree(sprom);
out:
if (res)
return res;
return err ? err : count;
}
/**
* ssb_arch_set_fallback_sprom - Set a fallback SPROM for use if no SPROM is found.
*
* @sprom: The SPROM data structure to register.
*
* With this function the architecture implementation may register a fallback
* SPROM data structure. The fallback is only used for PCI based SSB devices,
* where no valid SPROM can be found in the shadow registers.
*
* This function is useful for weird architectures that have a half-assed SSB device
* hardwired to their PCI bus.
*
* Note that it does only work with PCI attached SSB devices. PCMCIA devices currently
* don't use this fallback.
* Architectures must provide the SPROM for native SSB devices anyway,
* so the fallback also isn't used for native devices.
*
* This function is available for architecture code, only. So it is not exported.
*/
int ssb_arch_set_fallback_sprom(const struct ssb_sprom *sprom)
{
if (fallback_sprom)
return -EEXIST;
fallback_sprom = sprom;
return 0;
}
const struct ssb_sprom *ssb_get_fallback_sprom(void)
{
return fallback_sprom;
}
/* http://bcm-v4.sipsolutions.net/802.11/IsSpromAvailable */
bool ssb_is_sprom_available(struct ssb_bus *bus)
{
/* status register only exists on chipcomon rev >= 11 and we need check
for >= 31 only */
/* this routine differs from specs as we do not access SPROM directly
on PCMCIA */
if (bus->bustype == SSB_BUSTYPE_PCI &&
bus->chipco.dev->id.revision >= 31)
return bus->chipco.capabilities & SSB_CHIPCO_CAP_SPROM;
return true;
}