1. 29 Sep, 2014 15 commits
  2. 26 Sep, 2014 5 commits
    • Sebastian Andrzej Siewior's avatar
      tty: serial: 8250_core: remove UART_IER_RDI in serial8250_stop_rx() · 9137568e
      Sebastian Andrzej Siewior authored
      serial8250_do_startup() adds UART_IER_RDI and UART_IER_RLSI to ier.
      serial8250_stop_rx() should remove both.
      This is what the serial-omap driver has been doing and is now moved to
      the 8250-core since it does no look to be *that* omap specific.
      Reviewed-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
      Reviewed-by: default avatarTony Lindgren <tony@atomide.com>
      Tested-by: default avatarTony Lindgren <tony@atomide.com>
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9137568e
    • Sebastian Andrzej Siewior's avatar
      tty: serial: 8250_core: use the ->line argument as a hint in serial8250_find_match_or_unused() · 59b3e898
      Sebastian Andrzej Siewior authored
      Tony noticed that the old omap-serial driver picked the uart "number"
      based on the hint given from device tree or platform device's id.
      The 8250 based omap driver doesn't do this because the core code does
      not honour the ->line argument which is passed by the driver.
      
      This patch aims to keep the same behaviour as with omap-serial. The
      function will first try to use the line suggested ->line argument and
      then fallback to the old strategy in case the port is taken.
      
      That means the the third uart will always be ttyS2 even if the previous
      two have not been enabled in DT.
      Reviewed-by: default avatarTony Lindgren <tony@atomide.com>
      Tested-by: default avatarTony Lindgren <tony@atomide.com>
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      59b3e898
    • Sebastian Andrzej Siewior's avatar
      tty: serial: 8250_core: read only RX if there is something in the FIFO · 0aa525d1
      Sebastian Andrzej Siewior authored
      The serial8250_do_startup() function unconditionally clears the
      interrupts and for that it reads from the RX-FIFO without checking if
      there is a byte in the FIFO or not. This works fine on OMAP4+ HW like
      AM335x or DRA7.
      OMAP3630 ES1.1 (which means probably all OMAP3 and earlier) does not like
      this:
      
      |Unhandled fault: external abort on non-linefetch (0x1028) at 0xfb020000
      |Internal error: : 1028 [#1] ARM
      |Modules linked in:
      |CPU: 0 PID: 1 Comm: swapper Not tainted 3.16.0-00022-g7edcb57-dirty #1213
      |task: de0572c0 ti: de058000 task.ti: de058000
      |PC is at mem32_serial_in+0xc/0x1c
      |LR is at serial8250_do_startup+0x220/0x85c
      |Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
      |Control: 10c5387d  Table: 80004019  DAC: 00000015
      |[<c03051d4>] (mem32_serial_in) from [<c0307fe8>] (serial8250_do_startup+0x220/0x85c)
      |[<c0307fe8>] (serial8250_do_startup) from [<c0309e00>] (omap_8250_startup+0x5c/0xe0)
      |[<c0309e00>] (omap_8250_startup) from [<c030863c>] (serial8250_startup+0x18/0x2c)
      |[<c030863c>] (serial8250_startup) from [<c030394c>] (uart_startup+0x78/0x1d8)
      |[<c030394c>] (uart_startup) from [<c0304678>] (uart_open+0xe8/0x114)
      |[<c0304678>] (uart_open) from [<c02e9e10>] (tty_open+0x1a8/0x5a4)
      Reviewed-by: default avatarTony Lindgren <tony@atomide.com>
      Tested-by: default avatarTony Lindgren <tony@atomide.com>
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      0aa525d1
    • Sebastian Andrzej Siewior's avatar
      tty: serial: 8250_core: add run time pm · d74d5d1b
      Sebastian Andrzej Siewior authored
      While comparing the OMAP-serial and the 8250 part of this I noticed that
      the latter does not use run time-pm. Here are the pieces. It is
      basically a get before first register access and a last_busy + put after
      last access. This has to be enabled from userland _and_ UART_CAP_RPM is
      required for this.
      The runtime PM can usually work transparently in the background however
      there is one exception to this: After serial8250_tx_chars() completes
      there still may be unsent bytes in the FIFO (depending on CPU speed vs
      baud rate + flow control). Even if the TTY-buffer is empty we do not
      want RPM to disable the device because it won't send the remaining
      bytes. Instead we leave serial8250_tx_chars() with RPM enabled and wait
      for the FIFO empty interrupt. Once we enter serial8250_tx_chars() with
      an empty buffer we know that the FIFO is empty and since we are not going
      to send anything, we can disable the device.
      That xchg() is to ensure that serial8250_tx_chars() can be called
      multiple times and only the first invocation will actually invoke the
      runtime PM function. So that the last invocation of __stop_tx() will
      disable runtime pm.
      
      NOTE: do not enable RPM on the device unless you know what you do! If
      the device goes idle, it won't be woken up by incomming RX data _unless_
      there is a wakeup irq configured which is usually the RX pin configure
      for wakeup via the reset module. The RX activity will then wake up the
      device from idle. However the first character is garbage and lost. The
      following bytes will be received once the device is up in time. On the
      beagle board xm (omap3) it takes approx 13ms from the first wakeup byte
      until the first byte that is received properly if the device was in
      core-off.
      
      v5…v8:
      	- drop RPM from serial8250_set_mctrl() it will be used in
      	  restore path which already has RPM active and holds
      	  dev->power.lock
      v4…v5:
      	- add a wrapper around rpm function and introduce UART_CAP_RPM
      	  to ensure RPM put is invoked after the TX FIFO is empty.
      v3…v4:
      	- added runtime to the console code
      	- removed device_may_wakeup() from serial8250_set_sleep()
      
      Cc: mika.westerberg@linux.intel.com
      Reviewed-by: default avatarTony Lindgren <tony@atomide.com>
      Tested-by: default avatarTony Lindgren <tony@atomide.com>
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d74d5d1b
    • Sebastian Andrzej Siewior's avatar
      tty: serial: 8250_core: allow to set ->throttle / ->unthrottle callbacks · 234abab1
      Sebastian Andrzej Siewior authored
      The OMAP UART provides support for HW assisted flow control. What is
      missing is the support to throttle / unthrottle callbacks which are used
      by the omap-serial driver at the moment.
      This patch adds the callbacks. It should be safe to add them since they
      are only invoked from the serial_core (uart_throttle()) if the feature
      flags are set.
      Reviewed-by: default avatarTony Lindgren <tony@atomide.com>
      Tested-by: default avatarTony Lindgren <tony@atomide.com>
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      234abab1
  3. 25 Sep, 2014 1 commit
  4. 24 Sep, 2014 15 commits
  5. 20 Sep, 2014 1 commit
  6. 15 Sep, 2014 3 commits