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| /linux/drivers/net/can/sja1000/ |
| H A D | sja1000.h | diff 57c8a456640fa3ca777652f11f2db4179a3e66b6 Tue May 18 23:03:10 CEST 2010 Oliver Hartkopp <socketcan@hartkopp.net> can: Fix SJA1000 command register writes on SMP systems
The SJA1000 command register is concurrently written in the rx-path to free
the receive buffer _and_ in the tx-path to start the transmission.
The SJA1000 data sheet, 6.4.4 COMMAND REGISTER (CMR) states:
"Between two commands at least one internal clock cycle is needed in
order to proceed. The internal clock is half of the external oscillator
frequency."
On SMP systems the current implementation leads to a write stall in the
tx-path, which can be solved by adding some general locking and some time
to settle the write_reg() operation for the command register.
Thanks to Klaus Hitschler for the original fix and detailed problem
description.
This patch applies on net-2.6 and (with some offsets) on net-next-2.6 .
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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| H A D | sja1000.c | diff 1f01bfd202bc539bccd282befa2bbdb8d6ad80ee Wed May 19 08:46:38 CEST 2010 Oliver Hartkopp <socketcan@hartkopp.net> can: SJA1000 add missing spin_lock_init()
As remarked by Sam Ravnborg the spin_lock variable, that has been introduced
in commit 57c8a456640fa3ca777652f11f2db4179a3e66b6 ("can: Fix SJA1000 command
register writes on SMP systems") has not been initialized properly.
This patch adds the initialization to allow spinlock debugging.
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
CC: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff 57c8a456640fa3ca777652f11f2db4179a3e66b6 Tue May 18 23:03:10 CEST 2010 Oliver Hartkopp <socketcan@hartkopp.net> can: Fix SJA1000 command register writes on SMP systems
The SJA1000 command register is concurrently written in the rx-path to free
the receive buffer _and_ in the tx-path to start the transmission.
The SJA1000 data sheet, 6.4.4 COMMAND REGISTER (CMR) states:
"Between two commands at least one internal clock cycle is needed in
order to proceed. The internal clock is half of the external oscillator
frequency."
On SMP systems the current implementation leads to a write stall in the
tx-path, which can be solved by adding some general locking and some time
to settle the write_reg() operation for the command register.
Thanks to Klaus Hitschler for the original fix and detailed problem
description.
This patch applies on net-2.6 and (with some offsets) on net-next-2.6 .
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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