linux/drivers/bcma
Arend van Spriel 2bedea8f26 bcma: make bcma_core_pci_{up,down}() callable from atomic context
This patch removes the bcma_core_pci_power_save() call from
the bcma_core_pci_{up,down}() functions as it tries to schedule
thus requiring to call them from non-atomic context. The function
bcma_core_pci_power_save() is now exported so the calling module
can explicitly use it in non-atomic context. This fixes the
'scheduling while atomic' issue reported by Tod Jackson and
Joe Perches.

[   13.210710] BUG: scheduling while atomic: dhcpcd/1800/0x00000202
[   13.210718] Modules linked in: brcmsmac nouveau coretemp kvm_intel kvm cordic brcmutil bcma dell_wmi atl1c ttm mxm_wmi wmi
[   13.210756] CPU: 2 PID: 1800 Comm: dhcpcd Not tainted 3.11.0-wl #1
[   13.210762] Hardware name: Alienware M11x R2/M11x R2, BIOS A04 11/23/2010
[   13.210767]  ffff880177c92c40 ffff880170fd1948 ffffffff8169af5b 0000000000000007
[   13.210777]  ffff880170fd1ab0 ffff880170fd1958 ffffffff81697ee2 ffff880170fd19d8
[   13.210785]  ffffffff816a19f5 00000000000f4240 000000000000d080 ffff880170fd1fd8
[   13.210794] Call Trace:
[   13.210813]  [<ffffffff8169af5b>] dump_stack+0x4f/0x84
[   13.210826]  [<ffffffff81697ee2>] __schedule_bug+0x43/0x51
[   13.210837]  [<ffffffff816a19f5>] __schedule+0x6e5/0x810
[   13.210845]  [<ffffffff816a1c34>] schedule+0x24/0x70
[   13.210855]  [<ffffffff816a04fc>] schedule_hrtimeout_range_clock+0x10c/0x150
[   13.210867]  [<ffffffff810684e0>] ? update_rmtp+0x60/0x60
[   13.210877]  [<ffffffff8106915f>] ? hrtimer_start_range_ns+0xf/0x20
[   13.210887]  [<ffffffff816a054e>] schedule_hrtimeout_range+0xe/0x10
[   13.210897]  [<ffffffff8104f6fb>] usleep_range+0x3b/0x40
[   13.210910]  [<ffffffffa00371af>] bcma_pcie_mdio_set_phy.isra.3+0x4f/0x80 [bcma]
[   13.210921]  [<ffffffffa003729f>] bcma_pcie_mdio_write.isra.4+0xbf/0xd0 [bcma]
[   13.210932]  [<ffffffffa0037498>] bcma_pcie_mdio_writeread.isra.6.constprop.13+0x18/0x30 [bcma]
[   13.210942]  [<ffffffffa00374ee>] bcma_core_pci_power_save+0x3e/0x80 [bcma]
[   13.210953]  [<ffffffffa003765d>] bcma_core_pci_up+0x2d/0x60 [bcma]
[   13.210975]  [<ffffffffa03dc17c>] brcms_c_up+0xfc/0x430 [brcmsmac]
[   13.210989]  [<ffffffffa03d1a7d>] brcms_up+0x1d/0x20 [brcmsmac]
[   13.211003]  [<ffffffffa03d2498>] brcms_ops_start+0x298/0x340 [brcmsmac]
[   13.211020]  [<ffffffff81600a12>] ? cfg80211_netdev_notifier_call+0xd2/0x5f0
[   13.211030]  [<ffffffff815fa53d>] ? packet_notifier+0xad/0x1d0
[   13.211064]  [<ffffffff81656e75>] ieee80211_do_open+0x325/0xf80
[   13.211076]  [<ffffffff8106ac09>] ? __raw_notifier_call_chain+0x9/0x10
[   13.211086]  [<ffffffff81657b41>] ieee80211_open+0x71/0x80
[   13.211101]  [<ffffffff81526267>] __dev_open+0x87/0xe0
[   13.211109]  [<ffffffff8152650c>] __dev_change_flags+0x9c/0x180
[   13.211117]  [<ffffffff815266a3>] dev_change_flags+0x23/0x70
[   13.211127]  [<ffffffff8158cd68>] devinet_ioctl+0x5b8/0x6a0
[   13.211136]  [<ffffffff8158d5c5>] inet_ioctl+0x75/0x90
[   13.211147]  [<ffffffff8150b38b>] sock_do_ioctl+0x2b/0x70
[   13.211155]  [<ffffffff8150b681>] sock_ioctl+0x71/0x2a0
[   13.211169]  [<ffffffff8114ed47>] do_vfs_ioctl+0x87/0x520
[   13.211180]  [<ffffffff8113f159>] ? ____fput+0x9/0x10
[   13.211198]  [<ffffffff8106228c>] ? task_work_run+0x9c/0xd0
[   13.211202]  [<ffffffff8114f271>] SyS_ioctl+0x91/0xb0
[   13.211208]  [<ffffffff816aa252>] system_call_fastpath+0x16/0x1b
[   13.211217] NOHZ: local_softirq_pending 202

The issue was introduced in v3.11 kernel by following commit:

commit aa51e598d0
Author: Hauke Mehrtens <hauke@hauke-m.de>
Date:   Sat Aug 24 00:32:31 2013 +0200

    brcmsmac: use bcma PCIe up and down functions

    replace the calls to bcma_core_pci_extend_L1timer() by calls to the
    newly introduced bcma_core_pci_ip() and bcma_core_pci_down()

    Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
    Cc: Arend van Spriel <arend@broadcom.com>
    Signed-off-by: John W. Linville <linville@tuxdriver.com>

This fix has been discussed with Hauke Mehrtens [1] selection
option 3) and is intended for v3.12.

Ref:
[1] http://mid.gmane.org/5239B12D.3040206@hauke-m.de

Cc: <stable@vger.kernel.org> # 3.11.x
Cc: Tod Jackson <tod.jackson@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Rafal Milecki <zajec5@gmail.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2013-09-26 14:02:33 -04:00
..
bcma_private.h bcma: add support for BCM43142 2013-06-27 13:42:16 -04:00
core.c bcma: update core (en|dis)abling functions 2013-06-17 14:38:53 -04:00
driver_chipcommon_nflash.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless 2013-02-14 14:23:33 -05:00
driver_chipcommon_pmu.c bcma: add support for BCM43142 2013-06-27 13:42:16 -04:00
driver_chipcommon_sflash.c bcma: use const for serial flash hardware table 2013-06-17 14:38:53 -04:00
driver_chipcommon.c bcma: add support for BCM43142 2013-06-27 13:42:16 -04:00
driver_gmac_cmn.c Drivers: bcma: remove __dev* attributes. 2013-01-03 15:57:15 -08:00
driver_gpio.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless 2013-02-14 14:23:33 -05:00
driver_mips.c bcma_mips: add a const qualifier 2013-04-05 13:04:07 +01:00
driver_pci_host.c bcma: change max PCI read request size to 128 2013-08-26 14:09:02 -04:00
driver_pci.c bcma: make bcma_core_pci_{up,down}() callable from atomic context 2013-09-26 14:02:33 -04:00
host_pci.c bcma: add support for BCM43142 2013-06-27 13:42:16 -04:00
host_soc.c
Kconfig bcma: make it possible to select SoC support without mips 2013-07-22 16:54:39 -04:00
main.c bcma: return correct error code when bus scan failed 2013-07-22 16:54:40 -04:00
Makefile
README
scan.c bcma: fix error code handling on 64 Bit systems 2013-09-09 14:44:33 -04:00
scan.h
sprom.c bcma: add support for BCM43142 2013-06-27 13:42:16 -04:00
TODO

Broadcom introduced new bus as replacement for older SSB. It is based on AMBA,
however from programming point of view there is nothing AMBA specific we use.

Standard AMBA drivers are platform specific, have hardcoded addresses and use
AMBA standard fields like CID and PID.

In case of Broadcom's cards every device consists of:
1) Broadcom specific AMBA device. It is put on AMBA bus, but can not be treated
   as standard AMBA device. Reading it's CID or PID can cause machine lockup.
2) AMBA standard devices called ports or wrappers. They have CIDs (AMBA_CID)
   and PIDs (0x103BB369), but we do not use that info for anything. One of that
   devices is used for managing Broadcom specific core.

Addresses of AMBA devices are not hardcoded in driver and have to be read from
EPROM.

In this situation we decided to introduce separated bus. It can contain up to
16 devices identified by Broadcom specific fields: manufacturer, id, revision
and class.