Commit Graph

107 Commits

Author SHA1 Message Date
Gavin Shan d8cedaabe7 net/ncsi: Avoid unused-value build warning from ia64-linux-gcc
xchg() is used to set NCSI channel's state in order for consistent
access to the state. xchg()'s return value should be used. Otherwise,
one build warning will be raised (with -Wunused-value) as below message
indicates. It is reported by ia64-linux-gcc (GCC) 4.9.0.

 net/ncsi/ncsi-manage.c: In function 'ncsi_channel_monitor':
 arch/ia64/include/uapi/asm/cmpxchg.h:56:2: warning: value computed is \
 not used [-Wunused-value]
  ((__typeof__(*(ptr))) __xchg((unsigned long) (x), (ptr), sizeof(*(ptr))))
   ^
 net/ncsi/ncsi-manage.c:202:3: note: in expansion of macro 'xchg'
  xchg(&nc->state, NCSI_CHANNEL_INACTIVE);

This removes the atomic access to NCSI channel's state avoid the above
build warning. We have to hold the channel's lock when its state is readed
or updated. No functional changes introduced.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-04 02:11:50 -04:00
Arnd Bergmann a1b43eddae net/ncsi: avoid maybe-uninitialized warning
gcc-4.9 and higher warn about the newly added NSCI code:

net/ncsi/ncsi-manage.c: In function 'ncsi_process_next_channel':
net/ncsi/ncsi-manage.c:1003:2: error: 'old_state' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The warning is a false positive and therefore harmless, but it would be good to
avoid it anyway. I have determined that the barrier in the spin_unlock_irqsave()
is what confuses gcc to the point that it cannot track whether the variable
was unused or not.

This rearranges the code in a way that makes it obvious to gcc that old_state
is always initialized at the time of use, functionally this should not
change anything.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-25 10:32:59 -07:00
Gavin Shan 7a82ecf4cf net/ncsi: NCSI AEN packet handler
This introduces NCSI AEN packet handlers that result in (A) the
currently active channel is reconfigured; (B) Currently active
channel is deconfigured and disabled, another channel is chosen
as active one and configured. Case (B) won't happen if hardware
arbitration has been enabled, the channel that was in active
state is suspended simply.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-19 20:49:17 -07:00
Gavin Shan e6f44ed6d0 net/ncsi: Package and channel management
This manages NCSI packages and channels:

 * The available packages and channels are enumerated in the first
   time of calling ncsi_start_dev(). The channels' capabilities are
   probed in the meanwhile. The NCSI network topology won't change
   until the NCSI device is destroyed.
 * There in a queue in every NCSI device. The element in the queue,
   channel, is waiting for configuration (bringup) or suspending
   (teardown). The channel's state (inactive/active) indicates the
   futher action (configuration or suspending) will be applied on the
   channel. Another channel's state (invisible) means the requested
   action is being applied.
 * The hardware arbitration will be enabled if all available packages
   and channels support it. All available channels try to provide
   service when hardware arbitration is enabled. Otherwise, one channel
   is selected as the active one at once.
 * When channel is in active state, meaning it's providing service, a
   timer started to retrieve the channe's link status. If the channel's
   link status fails to be updated in the determined period, the channel
   is going to be reconfigured. It's the error handling implementation
   as defined in NCSI spec.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-19 20:49:17 -07:00
Gavin Shan 138635cc27 net/ncsi: NCSI response packet handler
The NCSI response packets are sent to MC (Management Controller)
from the remote end. They are responses of NCSI command packets
for multiple purposes: completion status of NCSI command packets,
return NCSI channel's capability or configuration etc.

This defines struct to represent NCSI response packets and introduces
function ncsi_rcv_rsp() which will be used to receive NCSI response
packets and parse them.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-19 20:49:17 -07:00
Gavin Shan 6389eaa7fa net/ncsi: NCSI command packet handler
The NCSI command packets are sent from MC (Management Controller)
to remote end. They are used for multiple purposes: probe existing
NCSI package/channel, retrieve NCSI channel's capability, configure
NCSI channel etc.

This defines struct to represent NCSI command packets and introduces
function ncsi_xmit_cmd(), which will be used to transmit NCSI command
packet according to the request. The request is represented by struct
ncsi_cmd_arg.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-19 20:49:16 -07:00
Gavin Shan 2d283bdd07 net/ncsi: Resource management
NCSI spec (DSP0222) defines several objects: package, channel, mode,
filter, version and statistics etc. This introduces the data structs
to represent those objects and implement functions to manage them.
Also, this introduces CONFIG_NET_NCSI for the newly implemented NCSI
stack.

   * The user (e.g. netdev driver) dereference NCSI device by
     "struct ncsi_dev", which is embedded to "struct ncsi_dev_priv".
     The later one is used by NCSI stack internally.
   * Every NCSI device can have multiple packages simultaneously, up
     to 8 packages. It's represented by "struct ncsi_package" and
     identified by 3-bits ID.
   * Every NCSI package can have multiple channels, up to 32. It's
     represented by "struct ncsi_channel" and identified by 5-bits ID.
   * Every NCSI channel has version, statistics, various modes and
     filters. They are represented by "struct ncsi_channel_version",
     "struct ncsi_channel_stats", "struct ncsi_channel_mode" and
     "struct ncsi_channel_filter" separately.
   * Apart from AEN (Asynchronous Event Notification), the NCSI stack
     works in terms of command and response. This introduces "struct
     ncsi_req" to represent a complete NCSI transaction made of NCSI
     request and response.

link: https://www.dmtf.org/sites/default/files/standards/documents/DSP0222_1.1.0.pdf
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-19 20:49:16 -07:00