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| author | Paul Gortmaker <paul.gortmaker@windriver.com> | 2011-12-04 23:42:23 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-12-10 03:14:13 (GMT) |
| commit | 9deaa53ac7fa373623123aa4f18828dd62292b1a (patch) | |
| tree | 938b41e9c534582f9152386ce1ee6893c3274c6b /drivers/tty/serial/Kconfig | |
| parent | 86b21199fc45e0052e181fefc07c747e9dc903b3 (diff) | |
| download | linux-9deaa53ac7fa373623123aa4f18828dd62292b1a.tar.xz | |
serial: add irq handler for Freescale 16550 errata.
Sending a break on the SOC UARTs found in some MPC83xx/85xx/86xx
chips seems to cause a short lived IRQ storm (/proc/interrupts
typically shows somewhere between 300 and 1500 events). Unfortunately
this renders SysRQ over the serial console completely inoperable.
The suggested workaround in the errata is to read the Rx register,
wait one character period, and then read the Rx register again.
We achieve this by tracking the old LSR value, and on the subsequent
interrupt event after a break, we don't read LSR, instead we just
read the RBR again and return immediately.
The "fsl,ns16550" is used in the compatible field of the serial
device to mark UARTs known to have this issue.
Thanks to Scott Wood for providing the errata data which led to
a much cleaner fix.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/tty/serial/Kconfig')
| -rw-r--r-- | drivers/tty/serial/Kconfig | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index 705d2dc..fee9e04 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -97,6 +97,11 @@ config SERIAL_8250_PNP This builds standard PNP serial support. You may be able to disable this feature if you only need legacy serial support. +config SERIAL_8250_FSL + bool + depends on SERIAL_8250 && PPC + default PPC + config SERIAL_8250_HP300 tristate depends on SERIAL_8250 && HP300 |