linux.git/drivers/tty/serial/8250, branch v5.16

serial: 8250_fintek: Fix garbled text for console

2021-12-15T20:51:07+00:00

Commit fab8a02b73eb ("serial: 8250_fintek: Enable high speed mode on Fintek F81866")
introduced support to use high baudrate with Fintek SuperIO UARTs. It'll
change clocksources when the UART probed.

But when user add kernel parameter "console=ttyS0,115200 console=tty0" to make
the UART as console output, the console will output garbled text after the
following kernel message.

[    3.681188] Serial: 8250/16550 driver, 32 ports, IRQ sharing enabled

The issue is occurs in following step:
	probe_setup_port() -> fintek_8250_goto_highspeed()

It change clocksource from 115200 to 921600 with wrong time, it should change
clocksource in set_termios() not in probed. The following 3 patches are
implemented change clocksource in fintek_8250_set_termios().

Commit 58178914ae5b ("serial: 8250_fintek: UART dynamic clocksource on Fintek F81216H")
Commit 195638b6d44f ("serial: 8250_fintek: UART dynamic clocksource on Fintek F81866")
Commit 423d9118c624 ("serial: 8250_fintek: Add F81966 Support")

Due to the high baud rate had implemented above 3 patches and the patch
Commit fab8a02b73eb ("serial: 8250_fintek: Enable high speed mode on Fintek F81866")
is bugged, So this patch will remove it.

Fixes: fab8a02b73eb ("serial: 8250_fintek: Enable high speed mode on Fintek F81866")
Signed-off-by: Ji-Ze Hong (Peter Hong) 
Link: https://lore.kernel.org/r/20211215075835.2072-1-hpeter+linux_kernel@gmail.com
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_bcm7271: UART errors after resuming from S2

2021-12-03T13:14:49+00:00

There is a small window in time during resume where the hardware
flow control signal RTS can be asserted (which allows a sender to
resume sending data to the UART) but the baud rate has not yet
been restored. This will cause corrupted data and FRAMING, OVERRUN
and BREAK errors. This is happening because the MCTRL register is
shadowed in uart_port struct and is later used during resume to set
the MCTRL register during both serial8250_do_startup() and
uart_resume_port(). Unfortunately, serial8250_do_startup()
happens before the UART baud rate is restored. The fix is to clear
the shadowed mctrl value at the end of suspend and restore it at the
end of resume.

Fixes: 41a469482de2 ("serial: 8250: Add new 8250-core based Broadcom STB driver")
Acked-by: Florian Fainelli 
Signed-off-by: Al Cooper 
Link: https://lore.kernel.org/r/20211201201402.47446-1-alcooperx@gmail.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: rewrite pericom_do_set_divisor()

2021-11-25T17:42:15+00:00

Have pericom_do_set_divisor() use the uartclk instead of a hard coded
value to work with different speed crystals. Tested with 14.7456 and 24
MHz crystals.

Have pericom_do_set_divisor() always calculate the divisor rather than
call serial8250_do_set_divisor() for rates below baud_base.

Do not write registers or call serial8250_do_set_divisor() if valid
divisors could not be found.

Fixes: 6bf4e42f1d19 ("serial: 8250: Add support for higher baud rates to Pericom chips")
Cc: stable 
Signed-off-by: Jay Dolan 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20211122120604.3909-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Fix ACCES entries in pci_serial_quirks array

2021-11-25T17:42:10+00:00

Fix error in table for PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4S that caused it
and PCI_DEVICE_ID_ACCESIO_PCIE_ICM232_4 to be missing their fourth port.

Fixes: 78d3820b9bd3 ("serial: 8250_pci: Have ACCES cards that use the four port Pericom PI7C9X7954 chip use the pci_pericom_setup()")
Cc: stable 
Signed-off-by: Jay Dolan 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20211122120604.3909-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250: Fix RTS modem control while in rs485 mode

2021-11-25T17:41:09+00:00

Commit f45709df7731 ("serial: 8250: Don't touch RTS modem control while
in rs485 mode") sought to prevent user space from interfering with rs485
communication by ignoring a TIOCMSET ioctl() which changes RTS polarity.

It did so in serial8250_do_set_mctrl(), which turns out to be too deep
in the call stack:  When a uart_port is opened, RTS polarity is set by
the rs485-aware function uart_port_dtr_rts().  It calls down to
serial8250_do_set_mctrl() and that particular RTS polarity change should
*not* be ignored.

The user-visible result is that on 8250_omap ports which use rs485 with
inverse polarity (RTS bit in MCR register is 1 to receive, 0 to send),
a newly opened port initially sets up RTS for sending instead of
receiving.  That's because omap_8250_startup() sets the cached value
up->mcr to 0 and omap_8250_restore_regs() subsequently writes it to the
MCR register.  Due to the commit, serial8250_do_set_mctrl() preserves
that incorrect register value:

do_sys_openat2
  do_filp_open
    path_openat
      vfs_open
        do_dentry_open
	  chrdev_open
	    tty_open
	      uart_open
	        tty_port_open
		  uart_port_activate
		    uart_startup
		      uart_port_startup
		        serial8250_startup
			  omap_8250_startup # up->mcr = 0
			uart_change_speed
			  serial8250_set_termios
			    omap_8250_set_termios
			      omap_8250_restore_regs
			        serial8250_out_MCR # up->mcr written
		  tty_port_block_til_ready
		    uart_dtr_rts
		      uart_port_dtr_rts
		        serial8250_set_mctrl
			  omap8250_set_mctrl
			    serial8250_do_set_mctrl # mcr[1] = 1 ignored

Fix by intercepting RTS changes from user space in uart_tiocmset()
instead.

Link: https://lore.kernel.org/linux-serial/20211027111644.1996921-1-baocheng.su@siemens.com/
Fixes: f45709df7731 ("serial: 8250: Don't touch RTS modem control while in rs485 mode")
Cc: Chao Zeng 
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Su Bao Cheng 
Reported-by: Jan Kiszka 
Tested-by: Su Bao Cheng 
Signed-off-by: Lukas Wunner 
Link: https://lore.kernel.org/r/21170e622a1aaf842a50b32146008b5374b3dd1d.1637596432.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Remove empty stub pci_quatech_exit()

2021-10-26T17:18:10+00:00

The ->exit() callback is checked for presence anyway,
no need to have an empty stub.

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20211026133452.61657-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Replace custom pci_match_id() implementation

2021-10-26T17:18:10+00:00

Replace pci_quatech_amcc() with generic pci_match_id().

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20211026133452.61657-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Replace dev_() by pci_() macros

2021-10-26T06:41:20+00:00

PCI subsystem provides convenient shortcut macros for message printing.
Use those macros instead of dev_*().

Signed-off-by: Andy Shevchenko 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20211022135147.70965-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Get rid of redundant 'else' keyword

2021-10-26T06:41:13+00:00

The 'else' keyword is not needed when previous conditional branch returns
to the upper layer. Get rid of redundant 'else' keyword in such cases.

Signed-off-by: Andy Shevchenko 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20211022135147.70965-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Refactor the loop in pci_ite887x_init()

2021-10-26T06:41:00+00:00

The loop can be refactored by using ARRAY_SIZE() instead of NULL terminator.
This reduces code base and makes it easier to read and understand.

Signed-off-by: Andy Shevchenko 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20211022135147.70965-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman