linux/drivers/tty, branch v4.0

tty: serial: fsl_lpuart: clear receive flag on FIFO flush

2015-03-26T22:13:14Z

When the receiver was enabled during startup, a character could have been in the FIFO when the UART get initially used. The driver configures the (receive) watermark level, and flushes the FIFO. However, the receive flag (RDRF) could still be set at that stage (as mentioned in the register description of UARTx_RWFIFO). This leads to an interrupt which won't be handled properly in interrupt mode: The receive interrupt function lpuart_rxint checks the FIFO count, which is 0 at that point (due to the flush during initialization). The problem does not manifest when using DMA to receive characters. Fix this situation by explicitly read the status register, which leads to clearing of the RDRF flag. Due to the flush just after the status flag read, a explicit data read is not to required. Signed-off-by: Stefan Agner Cc: stable Signed-off-by: Greg Kroah-Hartman

tty: serial: fsl_lpuart: specify transmit FIFO size

2015-03-26T22:13:14Z

Specify transmit FIFO size which might be different depending on LPUART instance. This makes sure uart_wait_until_sent in serial core getting called, which in turn waits and checks if the FIFO is really empty on shutdown by using the tx_empty callback. Without the call of this callback, the last several characters might not yet be transmitted when closing the serial port. This can be reproduced by simply using echo and redirect the output to a ttyLP device. Signed-off-by: Stefan Agner Cc: stable Signed-off-by: Greg Kroah-Hartman

serial: samsung: Clear operation mode on UART shutdown

2015-03-26T22:13:14Z

Exynos serial ports operate either in a DMA-based or interrupt-based modes. In DMA-based mode, the UART generates a transfer data request and a Transmission (Tx) interrupt in interrupt-based mode. The Tx IRQ is only unmasked in interrupt-based mode and it was done in s3c24xx_serial_start_tx(). Commit ba019a3e2ad5 ("serial: samsung: remove redundant interrupt enabling") removed the IRQ enable on that function since it is enabled when the mode is set in enable_tx_pio(). The problem is that enable_tx_pio() is only called if the port mode has not been set before but the mode was not cleared on .shutdown(). So if the UART was shutdown and then started up again, the mode set will remain and the Tx IRQ won't be unmasked. This caused a hang on at least Exynos5250, Exynos5420 and Exynos5800 when the system is rebooted or powered off. Fixes: ba019a3e2ad5 ("serial: samsung: remove redundant interrupt enabling") Signed-off-by: Javier Martinez Canillas Reviewed-by: Sylwester Nawrocki Signed-off-by: Greg Kroah-Hartman

serial: 8250_dw: Fix deadlock in LCR workaround

2015-03-11T15:39:52Z

Trying to write console output from within the serial console driver while the port->lock is held causes recursive deadlock: CPU 0 spin_lock_irqsave(&port->lock) printk() console_unlock() call_console_drivers() serial8250_console_write() spin_lock_irqsave(&port->lock) ** DEADLOCK ** The 8250_dw i/o accessors try to write a console error message if the LCR workaround was unsuccessful. When the port->lock is already held (eg., when called from serial8250_set_termios()), this deadlocks. Make the error message a FIXME until a general solution is devised. Cc: Tim Kryger Reported-by: Zhang Zhen Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

Merge tag 'tty-4.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2015-03-08T19:25:40Z

Pull tty/serial fixes from Greg KH: "Here are some tty and serial driver fixes for 4.0-rc3. Along with the atime fix that you know about, here are some other serial driver bugfixes as well. Most notable is a wait_until_sent bugfix that was traced back to being around since before 2.6.12 that Johan has fixed up. All have been in linux-next successfully" * tag 'tty-4.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: TTY: fix tty_wait_until_sent maximum timeout TTY: fix tty_wait_until_sent on 64-bit machines USB: serial: fix infinite wait_until_sent timeout TTY: bfin_jtag_comm: remove incorrect wait_until_sent operation net: irda: fix wait_until_sent poll timeout serial: uapi: Declare all userspace-visible io types serial: core: Fix iotype userspace breakage serial: sprd: Fix missing spin_unlock in sprd_handle_irq() console: Fix console name size mismatch tty: fix up atime/mtime mess, take four serial: 8250_dw: Fix get_mctrl behaviour serial:8250:8250_pci: delete unneeded quirk entries serial:8250:8250_pci: fix redundant entry report for WCH_CH352_2S Change email address for 8250_pci serial: 8250: Revert "tty: serial: 8250_core: read only RX if there is something in the FIFO" Revert "tty/serial: of_serial: add DT alias ID handling"

TTY: fix tty_wait_until_sent maximum timeout

2015-03-07T02:44:15Z

Currently tty_wait_until_sent may take up to twice as long as the requested timeout while waiting for driver and hardware buffers to drain. Fix this by taking the remaining number of jiffies after waiting for driver buffers to drain into account so that the timeout actually becomes a maximum timeout as it is documented to be. Note that this specifically implies tighter timings when closing a port as a consequence of actually honouring the port closing-wait setting for drivers relying on tty_wait_until_sent_from_close (e.g. via tty_port_close_start). Signed-off-by: Johan Hovold Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

TTY: fix tty_wait_until_sent on 64-bit machines

2015-03-07T02:44:14Z

Fix overflow bug in tty_wait_until_sent on 64-bit machines, where an infinite timeout (0) would be passed to the underlying tty-driver's wait_until_sent-operation as a negative timeout (-1), causing it to return immediately. This manifests itself for example as tcdrain() returning immediately, drivers not honouring the drain flags when setting terminal attributes, or even dropped data on close as a requested infinite closing-wait timeout would be ignored. The first symptom was reported by Asier LLANO who noted that tcdrain() returned prematurely when using the ftdi_sio usb-serial driver. Fix this by passing 0 rather than MAX_SCHEDULE_TIMEOUT (LONG_MAX) to the underlying tty driver. Note that the serial-core wait_until_sent-implementation is not affected by this bug due to a lucky chance (comparison to an unsigned maximum timeout), and neither is the cyclades one that had an explicit check for negative timeouts, but all other tty drivers appear to be affected. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable # v2.6.12 Reported-by: ZIV-Asier Llano Palacios Signed-off-by: Johan Hovold Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

TTY: bfin_jtag_comm: remove incorrect wait_until_sent operation

2015-03-07T02:44:14Z

Remove incorrect and redundant wait_until_sent operation, which waits for the driver buffer rather than any hardware buffers to drain, something which is already taken care of by the tty layer (and chars_in_buffer). Signed-off-by: Johan Hovold Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

serial: sprd: Fix missing spin_unlock in sprd_handle_irq()

2015-03-07T02:39:55Z

Fix return from sprd_handle_irq() with spin_lock held. Signed-off-by: Axel Lin Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: fix up atime/mtime mess, take four

2015-03-07T02:06:51Z

This problem was taken care of three times already in * b0de59b5733d18b0d1974a060860a8b5c1b36a2e (TTY: do not update atime/mtime on read/write), * 37b7f3c76595e23257f61bd80b223de8658617ee (TTY: fix atime/mtime regression), and * b0b885657b6c8ef63a46bc9299b2a7715d19acde (tty: fix up atime/mtime mess, take three) But it still misses one point. As John Paul correctly points out, we do not care about setting date. If somebody ever changes wall time backwards (by mistake for example), tty timestamps are never updated until the original wall time passes. So check the absolute difference of times and if it large than "8 seconds or so", always update the time. That means we will update immediatelly when changing time. Ergo, CAP_SYS_TIME can foul the check, but it was always that way. Thanks John for serving me this so nicely debugged. Signed-off-by: Jiri Slaby Reported-by: John Paul Perry Cc: # all, as b0b885657 was backported Acked-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman