linux/drivers/net/wireless/b43/rfkill.c
Larry Finger c2ff581aca b43: avoid PPC fault during resume
The routine b43_is_hw_radio_enabled() has long been a problem.
For PPC architecture with PHY Revision < 3, a read of the register
B43_MMIO_HWENABLED_LO will cause a CPU fault unless b43_status()
returns a value of 2 (B43_STAT_STARTED) (BUG 14181). Fixing that
results in Bug 14538 in which the driver is unable to reassociate
after resuming from hibernation because b43_status() returns 0.

The correct fix would be to determine why the status is 0; however,
I have not yet found why that happens. The correct value is found for
my device, which has PHY revision >= 3.

Returning TRUE when the PHY revision < 3 and b43_status() returns 0 fixes
the regression for 2.6.32.

This patch fixes the problem in Red Hat Bugzilla #538523.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Christian Casteyde <casteyde.christian@free.fr>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-12-04 13:28:49 -05:00

87 lines
2.4 KiB
C

/*
Broadcom B43 wireless driver
RFKILL support
Copyright (c) 2007 Michael Buesch <mb@bu3sch.de>
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) any 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; see the file COPYING. If not, write to
the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include "b43.h"
/* Returns TRUE, if the radio is enabled in hardware. */
bool b43_is_hw_radio_enabled(struct b43_wldev *dev)
{
if (dev->phy.rev >= 3 || dev->phy.type == B43_PHYTYPE_LP) {
if (!(b43_read32(dev, B43_MMIO_RADIO_HWENABLED_HI)
& B43_MMIO_RADIO_HWENABLED_HI_MASK))
return 1;
} else {
/* To prevent CPU fault on PPC, do not read a register
* unless the interface is started; however, on resume
* for hibernation, this routine is entered early. When
* that happens, unconditionally return TRUE.
*/
if (b43_status(dev) < B43_STAT_STARTED)
return 1;
if (b43_read16(dev, B43_MMIO_RADIO_HWENABLED_LO)
& B43_MMIO_RADIO_HWENABLED_LO_MASK)
return 1;
}
return 0;
}
/* The poll callback for the hardware button. */
void b43_rfkill_poll(struct ieee80211_hw *hw)
{
struct b43_wl *wl = hw_to_b43_wl(hw);
struct b43_wldev *dev = wl->current_dev;
struct ssb_bus *bus = dev->dev->bus;
bool enabled;
bool brought_up = false;
mutex_lock(&wl->mutex);
if (unlikely(b43_status(dev) < B43_STAT_INITIALIZED)) {
if (ssb_bus_powerup(bus, 0)) {
mutex_unlock(&wl->mutex);
return;
}
ssb_device_enable(dev->dev, 0);
brought_up = true;
}
enabled = b43_is_hw_radio_enabled(dev);
if (unlikely(enabled != dev->radio_hw_enable)) {
dev->radio_hw_enable = enabled;
b43info(wl, "Radio hardware status changed to %s\n",
enabled ? "ENABLED" : "DISABLED");
wiphy_rfkill_set_hw_state(hw->wiphy, !enabled);
if (enabled != dev->phy.radio_on)
b43_software_rfkill(dev, !enabled);
}
if (brought_up) {
ssb_device_disable(dev->dev, 0);
ssb_bus_may_powerdown(bus);
}
mutex_unlock(&wl->mutex);
}