kernel/linux.git/drivers/tty, branch v4.8.16

tty/serial: at91: fix hardware handshake on Atmel platforms

2016-11-18T09:51:49+00:00

commit 9bcffe7575b721d7b6d9b3090fe18809d9806e78 upstream. After commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when hardware handshake is enabled"), the hardware handshake wasn't functional anymore on Atmel platforms (beside SAMA5D2). To understand why, one has to understand the flag ATMEL_US_USMODE_HWHS first: Before commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when hardware handshake is enabled"), this flag was never set. Thus, the CTS/RTS where only handled by serial_core (and everything worked just fine). This commit introduced the use of the ATMEL_US_USMODE_HWHS flag, enabling it for all boards when the user space enables flow control. When the ATMEL_US_USMODE_HWHS is set, the Atmel USART controller handles a part of the flow control job: - disable the transmitter when the CTS pin gets high. - drive the RTS pin high when the DMA buffer transfer is completed or PDC RX buffer full or RX FIFO is beyond threshold. (depending on the controller version). NB: This feature is *not* mandatory for the flow control to work. (Nevertheless, it's very useful if low latencies are needed.) Now, the specifics of the ATMEL_US_USMODE_HWHS flag: - For platforms with DMAC and no FIFOs (sam9x25, sam9x35, sama5D3, sama5D4, sam9g15, sam9g25, sam9g35)* this feature simply doesn't work. ( source: https://lkml.org/lkml/2016/9/7/598 ) Tested it on sam9g35, the RTS pins always stays up, even when RXEN=1 or a new DMA transfer descriptor is set. => ATMEL_US_USMODE_HWHS must not be used for those platforms - For platforms with a PDC (sam926{0,1,3}, sam9g10, sam9g20, sam9g45, sam9g46)*, there's another kind of problem. Once the flag ATMEL_US_USMODE_HWHS is set, the RTS pin can't be driven anymore via RTSEN/RTSDIS in USART Control Register. The RTS pin can only be driven by enabling/disabling the receiver or setting RCR=RNCR=0 in the PDC (Receive (Next) Counter Register). => Doing this is beyond the scope of this patch and could add other bugs, so the original (and working) behaviour should be set for those platforms (meaning ATMEL_US_USMODE_HWHS flag should be unset). - For platforms with a FIFO (sama5d2)*, the RTS pin is driven according to the RX FIFO thresholds, and can be also driven by RTSEN/RTSDIS in USART Control Register. No problem here. (This was the use case of commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when hardware handshake is enabled")) NB: If the CTS pin declared as a GPIO in the DTS, (for instance cts-gpios = <&pioA PIN_PB31 GPIO_ACTIVE_LOW>), the transmitter will be disabled. => ATMEL_US_USMODE_HWHS flag can be set for this platform ONLY IF the CTS pin is not a GPIO. So, the only case when ATMEL_US_USMODE_HWHS can be enabled is when (atmel_use_fifo(port) && !mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) Tested on all Atmel USART controller flavours: AT91SAM9G35-CM (DMAC flavour), AT91SAM9G20-EK (PDC flavour), SAMA5D2xplained (FIFO flavour). * the list may not be exhaustive Fixes: 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when hardware handshake is enabled") Signed-off-by: Richard Genoud Acked-by: Alexandre Belloni Acked-by: Cyrille Pitchen Acked-by: Uwe Kleine-König [nicolas.ferre@atmel.com: adapt to 4.4.x kernel for stable by adding the atmel_port variable declaration which was missing] Signed-off-by: Nicolas Ferre Signed-off-by: Greg Kroah-Hartman

tty: vt, fix bogus division in csi_J

2016-11-10T15:38:57+00:00

commit 42acfc6615f47e465731c263bee0c799edb098f2 upstream. In csi_J(3), the third parameter of scr_memsetw (vc_screenbuf_size) is divided by 2 inappropriatelly. But scr_memsetw expects size, not count, because it divides the size by 2 on its own before doing actual memset-by-words. So remove the bogus division. Signed-off-by: Jiri Slaby Cc: Petr Písař Fixes: f8df13e0a9 (tty: Clean console safely) Signed-off-by: Greg Kroah-Hartman

tty: limit terminal size to 4M chars

2016-11-10T15:38:50+00:00

commit 32b2921e6a7461fe63b71217067a6cf4bddb132f upstream. Size of kmalloc() in vc_do_resize() is controlled by user. Too large kmalloc() size triggers WARNING message on console. Put a reasonable upper bound on terminal size to prevent WARNINGs. Signed-off-by: Dmitry Vyukov CC: David Rientjes Cc: One Thousand Gnomes Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: Peter Hurley Cc: linux-kernel@vger.kernel.org Cc: syzkaller@googlegroups.com Signed-off-by: Greg Kroah-Hartman

vt: clear selection before resizing

2016-11-10T15:38:50+00:00

commit 009e39ae44f4191188aeb6dfbf661b771dbbe515 upstream. When resizing a vt its selection may exceed the new size, resulting in an invalid memory access [1]. Clear the selection before resizing. [1] http://lkml.kernel.org/r/CACT4Y+acDTwy4umEvf5ROBGiRJNrxHN4Cn5szCXE5Jw-d1B=Xw@mail.gmail.com Reported-and-tested-by: Dmitry Vyukov Signed-off-by: Scot Doyle Signed-off-by: Greg Kroah-Hartman

serial: 8250_port: fix runtime PM use in __do_stop_tx_rs485()

2016-10-22T10:40:21+00:00

commit b3965767d86cf4534dfe1affbde0453d3224ed7f upstream. There are calls to serial8250_rpm_{get|put}() in __do_stop_tx_rs485() that are certainly placed in a wrong location. I dunno how it had been tested with runtime PM enabled because it is obvious "sleep in atomic context" error. Besides that serial8250_rpm_get() is called immediately after an IO just happened. It implies that the device is already powered on, see implementation of serial8250_em485_rts_after_send() and serial8250_clear_fifos() for the details. There is no bug have been seen due to, as I can guess, use of auto suspend mode when scheduled transaction to suspend is invoked quite lately than it's needed for a few writes to the port. It might be possible to trigger a warning if stop_tx_timer fires when device is suspended. Refactor the code to use runtime PM only in case of timer function. Fixes: 0c66940d584d ("tty/serial/8250: fix RS485 half-duplex RX") Cc: "Matwey V. Kornilov" Tested-by: Yegor Yefremov Signed-off-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman

serial: 8250_dw: Check the data->pclk when get apb_pclk

2016-10-22T10:40:21+00:00

commit e16b46f190a22587898b331f9d58583b0b166c9a upstream. It should check the data->pclk, not data->clk when get apb_pclk. Fixes: c8ed99d4f6a8("serial: 8250_dw: Add support for deferred probing") Signed-off-by: Kefeng Wang Tested-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman

BUG: atmel_serial: Interrupts not disabled on close

2016-10-22T10:40:21+00:00

commit 0ae9fdefb6c37237d826d6195e27810ffcc0b6e0 upstream. Since commit 18dfef9c7f87 ("serial: atmel: convert to irq handling provided mctrl-gpio"), interrupts from GPIOs are not disabled any more when the serial port is closed, leading to an oops when the one of the input pin is toggled (CTS/DSR/DCD/RNG). This is only the case if those pins are used as GPIOs, i.e. declared like that: usart1: serial@f8020000 { /* CTS and DTS will be handled by GPIO */ status = "okay"; rts-gpios = <&pioB 17 GPIO_ACTIVE_LOW>; cts-gpios = <&pioB 16 GPIO_ACTIVE_LOW>; dtr-gpios = <&pioB 14 GPIO_ACTIVE_LOW>; dsr-gpios = <&pioC 31 GPIO_ACTIVE_LOW>; rng-gpios = <&pioB 12 GPIO_ACTIVE_LOW>; dcd-gpios = <&pioB 15 GPIO_ACTIVE_LOW>; }; That's because modem interrupts used to be freed in atmel_shutdown(). After commit 18dfef9c7f87 ("serial: atmel: convert to irq handling provided mctrl-gpio"), this code was just removed. Calling atmel_disable_ms() disables the interrupts and everything works fine again. Tested on at91sam9g35-cm (This patch doesn't apply on -stable kernels, fixes for 4.4 and 4.7 will be sent after this one is applied.) Signed-off-by: Richard Genoud Fixes: 18dfef9c7f87 ("serial: atmel: convert to irq handling provided mctrl-gpio") Acked-by: Nicolas Ferre Acked-by: Uwe Kleine-König Signed-off-by: Greg Kroah-Hartman

serial: imx: Fix DCD reading

2016-10-22T10:40:21+00:00

commit 4b75f80003617fe35771a9e27022e8fbd6a41875 upstream. The USR2_DCDIN bit is tested for in register usr1. As the name suggests the usr2 register should be used instead. This fixes reading the Carrier detect status. Signed-off-by: Sascha Hauer Fixes: 90ebc4838666 ("serial: imx: repair and complete handshaking") Acked-by: Uwe Kleine-König Reviewed-by: Fabio Estevam Signed-off-by: Greg Kroah-Hartman

serial: 8250: added acces i/o products quad and octal serial cards

2016-08-31T14:28:26+00:00

Added devices ids for acces i/o products quad and octal serial cards that make use of existing Pericom PI7C9X7954 and PI7C9X7958 configurations . Signed-off-by: Jimi Damon Cc: stable Signed-off-by: Greg Kroah-Hartman

serial: 8250_mid: fix divide error bug if baud rate is 0

2016-08-31T13:49:26+00:00

Since the commit c1a67b48f6a5 ("serial: 8250_pci: replace switch-case by formula for Intel MID"), the 8250 driver crashes in the byt_set_termios() function with a divide error. This is caused by the fact that a baud rate of 0 (B0) is not handled properly. Fix it by falling back to B9600 in this case. Reported-by: "Mendez Salinas, Fernando" Fixes: c1a67b48f6a5 ("serial: 8250_pci: replace switch-case by formula for Intel MID") Cc: stable@vger.kernel.org Signed-off-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman