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  1. 05 10月, 2015 3 次提交
    • M
      serial: 8250: simplify ralink/alchemy register remap selection · 9b2256c8
      由 Mans Rullgard 提交于 
      Some SoCs, including Ralink/Mediatek and Alchemy Au1xxx, have a
16550-like UART with a non-standard register layout.  These are
supported by a simple mapping table in 8250_port.c  Rather than
list every SoC type using this access mode in the ifdefs there,
allow selecting the SERIAL_8250_RT288X Kconfig option with any
system and default it to y for the known cases needing it.  The
help text is reworded accordingly.

This change simplifies adding support for other SoCs also using
the same UART.

The name of the option is a little misleading, but not knowing
the true origin of this UART, it is as good a choice as any.
Signed-off-by: NMans Rullgard <mans@mansr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9b2256c8
    • T
      serial: 8250: Fix autoconfig_irq() to avoid race conditions · 9a23a1d1
      由 Taichi Kageyama 提交于 
      The following race conditions can happen when a serial port is used
as console.

Case1: CPU_B is used to detect an interrupt from a serial port,
       but it can have interrupts disabled during the waiting time.
Case2: CPU_B clears UART_IER just after CPU_A sets UART_IER and then
       a serial port may not make an interrupt.
Case3: CPU_A sets UART_IER just after CPU_B clears UART_IER.
       This is an unexpected behavior for serial8250_console_write().

CPU_A [autoconfig_irq]      |  CPU_B [serial8250_console_write]
----------------------------|---------------------------------------
                            |
probe_irq_on()              |  spin_lock_irqsave(&port->lock,)
serial_outp(,UART_IER,0x0f) |  serial_out(,UART_IER,0)
udelay(20);                 |  uart_console_write()
probe_irq_off()             |
                            |  spin_unlock_irqrestore(&port->lock,)

Case1 and 2 can make autoconfig_irq() failed.
In these cases, the console doesn't work in interrupt mode and
"input overrun" (which can make operation mistakes) can happen
on some systems. Especially in the Case1, It is known that the
problem happens with high rate every boot once it occurs
because the boot sequence is always almost same.

port mutex makes sure that the autoconfig operation is exclusive of
any other concurrent HW access except by the console operation.
console lock is required in autoconfig_irq().
Signed-off-by: NTaichi Kageyama <t-kageyama@cp.jp.nec.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9a23a1d1
    • M
      serial: don't register CIR serial ports · e4fda3a0
      由 Maciej S. Szmigiero 提交于 
      CIR type serial ports aren't real serial ports.

This is just a way to prevent legacy 8250 serial
driver from probing and eventually binding some
resources.

Since in current state such ports aren't providing
any real functionality and it is not possible
to change their type via setserial/ioctl(TIOCSSERIAL)
(due to UPF_FIXED_PORT flag set on them)
it is simpler and cleaner to not register them at all
with serial core.

Print a short message in this case so it is known
to user what has happened.

This way checks for PORT_8250_CIR in serial port
callbacks can be removed too, since they won't
ever be called.
Signed-off-by: NMaciej Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e4fda3a0
  3. 23 9月, 2015 1 次提交
  5. 24 7月, 2015 3 次提交
  7. 01 6月, 2015 1 次提交
  9. 11 5月, 2015 2 次提交
  11. 07 5月, 2015 2 次提交
  13. 15 4月, 2015 1 次提交
  15. 10 4月, 2015 2 次提交
  17. 27 3月, 2015 14 次提交
  19. 26 3月, 2015 6 次提交
  21. 07 3月, 2015 2 次提交
  23. 07 2月, 2015 1 次提交
  25. 03 2月, 2015 2 次提交