diff options
| author | Lukas Wunner <[email protected]> | 2022-11-09 08:04:34 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <[email protected]> | 2022-11-09 13:03:55 +0100 |
| commit | d85bf5105853d57ed27c6c21ac35424cc44a0fbb (patch) | |
| tree | 56ec6f0b1a2178095072f246b7fca6c92061978c /tools/testing/selftests/bpf/prog_tests/prog_array_init.c | |
| parent | 6a3ff858915fa8ca36c7eb02c87c9181ae2fc333 (diff) | |
serial: 8250: 8250_omap: Fix calculation of RS485 delays
Commit 801954d1210a ("serial: 8250: 8250_omap: Support native RS485")
calculates RS485 delays from the baudrate. The baudrate is generated
with either a 16x or 13x divisor. The divisor is set in the Mode
Definition Register 1 (MDR1).
The commit erroneously assumes that the register stores the divisor as
a bitmask and uses a logical AND to differentiate between 16x and 13x
divisors. However the divisor is really stored as a 3-bit mode
(see lines 363ff in include/uapi/linux/serial_reg.h).
The logical AND operation is performed with UART_OMAP_MDR1_16X_MODE,
which is defined as 0x0 and hence yields false. So the commit always
assumes a 13x divisor. Fix by using an equal comparison. This works
because we never set any of the other 5 bits in the register. (They
pertain to IrDA mode, which is not supported by the driver).
Fixes: 801954d1210a ("serial: 8250: 8250_omap: Support native RS485")
Link: https://lore.kernel.org/linux-serial/[email protected]/
Reported-by: kernel test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Lukas Wunner <[email protected]>
Reviewed-by: Ilpo Järvinen <[email protected]>
Link: https://lore.kernel.org/r/7d5b04da13d89b8708b9543a0b125f2b6062a77b.1667977259.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/prog_array_init.c')
0 files changed, 0 insertions, 0 deletions