linux-stable/drivers/tty
Stuart Menefy 5086e0a409 tty: serial: samsung: Enable baud clock during initialisation
The Exynos 5260, like the 5433, appears to require baud clock as
well as pclk to be running before accessing any of the registers,
otherwise an external abort is raised.

The serial driver already enables baud clock when required, but only
if it knows which clock is baud clock. On older SoCs baud clock may be
selected from a number of possible clocks so to support this the driver
only selects which clock to use for baud clock when a port is opened,
at which point the desired baud rate is known and the best clock can be
selected.

The result is that there are a number of circumstances in which
registers are accessed without first explicitly enabling baud clock:
 - while the driver is being initialised
 - the initial parts of opening a port for the first time
 - when resuming if the port hasn't been already opened

The 5433 overcomes this currently by marking the baud clock as
CLK_IGNORE_UNUSED, so the clock is always enabled, however
for the 5260 I've been trying to avoid this.

This change adds code to pick the first available clock to use
as baud clock and enables it while initialising the driver.

This code wouldn't be sufficient on a SoC which supports
multiple possible baud clock sources _and_ requires the
correct baud clock to be enabled before accessing any of the
serial port registers (in particular the register which selects
which clock to use as the baud clock).  As far as I know
such hardware doesn't exist.

Signed-off-by: Stuart Menefy <stuart.menefy@mathembedded.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-19 13:42:08 +01:00
..
hvc tty: Use of_node_name_{eq,prefix} for node name comparisons 2018-12-17 16:12:17 +01:00
ipwireless tty: ipwireless: Fix potential NULL pointer dereference 2019-01-30 12:03:58 +01:00
serdev serdev: ttyport: call tiocmget and tiocmset ops directly 2019-01-30 11:48:08 +01:00
serial tty: serial: samsung: Enable baud clock during initialisation 2019-02-19 13:42:08 +01:00
vt vt: perform safe console erase in the right order 2019-02-12 10:46:11 +01:00
amiserial.c kill TIOCSERGSTRUCT 2018-10-13 00:50:53 -04:00
cyclades.c cyclades: switch to ->[sg]et_serial() 2018-10-13 00:50:30 -04:00
ehv_bytechan.c tty: Convert to using %pOFn instead of device_node.name 2018-09-18 16:07:25 +02:00
goldfish.c headers: separate linux/mod_devicetable.h from linux/platform_device.h 2018-07-07 17:52:26 +02:00
isicom.c isicom: switch to ->[sg]et_serial() 2018-10-13 00:50:31 -04:00
Kconfig tty: ldisc: add sysctl to prevent autoloading of ldiscs 2019-01-30 09:31:30 +01:00
Makefile tty: remove bfin_jtag_comm and hvc_bfin_jtag drivers 2018-03-26 15:57:24 +02:00
mips_ejtag_fdc.c
moxa.c moxa: switch to ->[sg]et_serial() 2018-10-13 00:50:32 -04:00
moxa.h tty: moxa: Add support for CMSPAR 2017-11-28 15:32:33 +01:00
mxser.c mxser: switch to ->[sg]et_serial() 2018-10-13 00:50:32 -04:00
mxser.h
n_gsm.c n_gsm: Constify u8 and unsigned char usage 2019-01-18 12:57:40 +01:00
n_hdlc.c tty/n_hdlc: mark expected switch fall-through 2019-02-14 10:49:19 +01:00
n_null.c
n_r3964.c tty: Don't block on IO when ldisc change is pending 2018-12-05 12:16:33 +01:00
n_tracerouter.c
n_tracesink.c
n_tracesink.h
n_tty.c n_tty: update comment for WAKEUP_CHARS define 2019-01-18 13:25:11 +01:00
nozomi.c tty/nozomi: use pci_iomap instead of ioremap_nocache 2019-02-12 10:26:45 +01:00
pty.c pty: fix compat ioctls 2018-10-13 00:50:51 -04:00
rocket.c tty: rocket: Fix possible buffer overwrite on register_PCI 2018-08-02 10:11:32 +02:00
rocket.h
rocket_int.h
synclink.c tty/synclink: remove ISA support 2019-02-12 08:51:33 +01:00
synclink_gt.c synclink_gt(): fix compat_ioctl() 2018-10-13 00:50:52 -04:00
synclinkmp.c synclink: reduce pointless checks in ->ioctl() 2018-10-13 00:50:43 -04:00
sysrq.c sysrq: Remove duplicated sysrq message 2019-01-22 13:46:53 +01:00
tty_audit.c audit: use current whenever possible 2018-11-26 18:41:21 -05:00
tty_baudrate.c termios, tty/tty_baudrate.c: fix buffer overrun 2018-11-08 03:36:45 -08:00
tty_buffer.c tty: increase the default flip buffer limit to 2*640K 2019-01-30 12:03:58 +01:00
tty_io.c tty: ldisc: add sysctl to prevent autoloading of ldiscs 2019-01-30 09:31:30 +01:00
tty_ioctl.c move compat handling of tty ioctls to tty_compat_ioctl() 2018-09-14 11:12:17 -04:00
tty_jobctrl.c
tty_ldisc.c tty: ldisc: add sysctl to prevent autoloading of ldiscs 2019-01-30 09:31:30 +01:00
tty_ldsem.c tty/ldsem: Decrement wait_readers on timeouted down_read() 2018-12-05 12:16:33 +01:00
tty_mutex.c
tty_port.c tty: do not set TTY_IO_ERROR flag if console port 2018-11-27 09:58:11 +01:00
vcc.c