xiaomi-sm8450/android_kernel_xiaomi_sm8450
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ssb: do not read SPROM if it does not exist

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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>
This commit is contained in:
John W. Linville
2010-03-31 21:39:35 +02:00
parent 672724403b
commit d53cdbb94a
5 changed files with 39 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/ssb/driver_chipcommon.c
View File

@@ -233,6 +233,8 @@ void ssb_chipcommon_init(struct ssb_chipcommon *cc)
{
if (!cc->dev)
return; /* We don't have a ChipCommon */
if (cc->dev->id.revision >= 11)
cc->status = chipco_read32(cc, SSB_CHIPCO_CHIPSTAT);
ssb_pmu_init(cc);
chipco_powercontrol_init(cc);
ssb_chipco_set_clockmode(cc, SSB_CLKMODE_FAST);

5
drivers/ssb/pci.c
View File

@@ -620,6 +620,11 @@ static int ssb_pci_sprom_get(struct ssb_bus *bus,
int err = -ENOMEM;
u16 *buf;
if (!ssb_is_sprom_available(bus)) {
ssb_printk(KERN_ERR PFX "No SPROM available!\n");
return -ENODEV;
}
buf = kcalloc(SSB_SPROMSIZE_WORDS_R123, sizeof(u16), GFP_KERNEL);
if (!buf)
goto out;

14
drivers/ssb/sprom.c
View File

@@ -175,3 +175,17 @@ 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;
}