user/sven/linux.git/drivers/tty, branch v4.9.5

Clearing FIFOs in RS485 emulation mode causes subsequent transmits to break

2017-01-19T19:18:03Z

commit 2bed8a8e70729f996af92042d3ad0f11870acc1f upstream. When in RS485 emulation mode, __do_stop_tx_rs485() calls serial8250_clear_fifos(). This not only clears the FIFOs, but also sets all bits in their control register (UART_FCR) to 0. One of the effects of this is the disabling of the FIFOs, which turns them into single-byte holding registers. The rest of the driver doesn't know this, which results in the lions share of characters passed into a write call to be dropped. (I can supply logic analyzer screenshots if necessary) This fix replaces the serial8250_clear_fifos() call to serial8250_clear_and_reinit_fifos() - this prevents the "dropped characters" issue from manifesting again while retaining the requirement of clearing the RX FIFO after transmission if the SER_RS485_RX_DURING_TX flag is disabled. Signed-off-by: Daniel Jedrychowski Signed-off-by: Greg Kroah-Hartman

sysrq: attach sysrq handler correctly for 32-bit kernel

2017-01-19T19:18:03Z

commit 802c03881f29844af0252b6e22be5d2f65f93fd0 upstream. The sysrq input handler should be attached to the input device which has a left alt key. On 32-bit kernels, some input devices which has a left alt key cannot attach sysrq handler. Because the keybit bitmap in struct input_device_id for sysrq is not correctly initialized. KEY_LEFTALT is 56 which is greater than BITS_PER_LONG on 32-bit kernels. I found this problem when using a matrix keypad device which defines a KEY_LEFTALT (56) but doesn't have a KEY_O (24 == 56%32). Cc: Jiri Slaby Signed-off-by: Akinobu Mita Acked-by: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx

2017-01-19T19:18:03Z

commit 89d8232411a85b9a6b12fd5da4d07d8a138a8e0c upstream. If we don't disable the transmitter in atmel_stop_tx, the DMA buffer continues to send data until it is emptied. This cause problems with the flow control (CTS is asserted and data are still sent). So, disabling the transmitter in atmel_stop_tx is a sane thing to do. Tested on at91sam9g35-cm(DMA) Tested for regressions on sama5d2-xplained(Fifo) and at91sam9g20ek(PDC) Signed-off-by: Richard Genoud Acked-by: Nicolas Ferre Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done

2017-01-19T19:18:03Z

commit b389f173aaa1204d6dc1f299082a162eb0491545 upstream. When using RS485 in half duplex, RX should be enabled when TX is finished, and stopped when TX starts. Before commit 0058f0871efe7b01c6 ("tty/serial: atmel: fix RS485 half duplex with DMA"), RX was not disabled in atmel_start_tx() if the DMA was used. So, collisions could happened. But disabling RX in atmel_start_tx() uncovered another bug: RX was enabled again in the wrong place (in atmel_tx_dma) instead of being enabled when TX is finished (in atmel_complete_tx_dma), so the transmission simply stopped. This bug was not triggered before commit 0058f0871efe7b01c6 ("tty/serial: atmel: fix RS485 half duplex with DMA") because RX was never disabled before. Moving atmel_start_rx() in atmel_complete_tx_dma() corrects the problem. Reported-by: Gil Weber Fixes: 0058f0871efe7b01c6 Tested-by: Gil Weber Signed-off-by: Richard Genoud Acked-by: Alexandre Belloni Signed-off-by: Greg Kroah-Hartman

Revert "tty: serial: 8250: add CON_CONSDEV to flags"

2017-01-19T19:18:02Z

commit 6741f551a0b26479de2532ffa43a366747e6dbf3 upstream. This commit needs to be reverted because it prevents people from using the serial console as a secondary console with input being directed to tty0. IOW, if you boot with console=ttyS0 console=tty0 then all kernels prior to this commit will produce output on both ttyS0 and tty0 but input will only be taken from tty0. With this patch the serial console will always be the primary console instead of tty0, potentially preventing people from getting into their machines in emergency situations. Fixes: d03516df8375 ("tty: serial: 8250: add CON_CONSDEV to flags") Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman

sc16is7xx: Drop bogus use of IRQF_ONESHOT

2017-01-09T07:32:22Z

commit 04da73803c05dc1150ccc31cbf93e8cd56679c09 upstream. The use of IRQF_ONESHOT when registering an interrupt handler with request_irq() is non-sensical. Not only that, it also prevents the handler from being threaded when it otherwise should be w/ IRQ_FORCED_THREADING is enabled. This causes the following deadlock observed by Sean Nyekjaer on -rt: Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM [..] rt_spin_lock_slowlock from queue_kthread_work queue_kthread_work from sc16is7xx_irq sc16is7xx_irq [sc16is7xx] from handle_irq_event_percpu handle_irq_event_percpu from handle_irq_event handle_irq_event from handle_level_irq handle_level_irq from generic_handle_irq generic_handle_irq from mxc_gpio_irq_handler mxc_gpio_irq_handler from mx3_gpio_irq_handler mx3_gpio_irq_handler from generic_handle_irq generic_handle_irq from __handle_domain_irq __handle_domain_irq from gic_handle_irq gic_handle_irq from __irq_svc __irq_svc from rt_spin_unlock rt_spin_unlock from kthread_worker_fn kthread_worker_fn from kthread kthread from ret_from_fork Fixes: 9e6f4ca3e567 ("sc16is7xx: use kthread_worker for tx_work and irq") Reported-by: Sean Nyekjaer Signed-off-by: Josh Cartwright Cc: linux-rt-users@vger.kernel.org Cc: Jakub Kicinski Cc: linux-serial@vger.kernel.org Cc: Sebastian Andrzej Siewior Signed-off-by: Julia Cartwright Acked-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

vt: fix Scroll Lock LED trigger name

2017-01-09T07:32:21Z

commit 31b5929d533f5183972cf57a7844b456ed996f3c upstream. There is a disagreement between drivers/tty/vt/keyboard.c and drivers/input/input-leds.c with regard to what is a Scroll Lock LED trigger name: input calls it "kbd-scrolllock", but vt calls it "kbd-scrollock" (two l's). This prevents Scroll Lock LED trigger from binding to this LED by default. Since it is a scroLL Lock LED, this interface was introduced only about a year ago and in an Internet search people seem to reference this trigger only to set it to this LED let's simply rename it to "kbd-scrolllock". Also, it looks like this was supposed to be changed before this code was merged: https://lkml.org/lkml/2015/6/9/697 but it was done only on the input side. Signed-off-by: Maciej S. Szmigiero Acked-by: Samuel Thibault Signed-off-by: Greg Kroah-Hartman

tty: serial_core: fix NULL struct tty pointer access in uart_write_wakeup

2016-10-28T12:13:07Z

Since commit 761ed4a94582ab29 ("tty: serial_core: convert uart_close to use tty_port_close"), the serial console is broken on various systems and typing "reboot" splats the following on the serial console: INIT: Sending p[ 427.863916] BUG: unable to handle kernel NULL pointer dereference at 00000000000001e0 [ 427.885156] IP: [] tty_wakeup+0xc/0x70 [ 427.898337] PGD 0 [ 427.902051] [ 427.907498] Oops: 0000 [#1] PREEMPT SMP [ 427.917635] Modules linked in: nfsv3 nfs_acl nfs fscache lockd sunrpc grace edd af_packet cpufreq_conservative cpufreq_userspace cpufreq_powersave fuse loop md_mod dm_mod joydev hid_generic usbhid ipmi_ssif ohci_pci ohci_hcd ehci_pci ehci_hcd e1000e ptp firewire_ohci edac_core pps_core tpm_infineon sp5100_tco firewire_core acpi_cpufreq serio_raw pcspkr fjes usbcore shpchp edac_mce_amd tpm_tis ipmi_si tpm_tis_core i2c_piix4 k10temp sg ipmi_msghandler tpm sr_mod button cdrom kvm_amd kvm irqbypass crc_itu_t ast ttm drm_kms_helper drm fb_sys_fops sysimgblt sysfillrect syscopyarea i2c_algo_bit scsi_dh_rdac scsi_dh_alua scsi_dh_emc scsi_dh_hp_sw ata_generic pata_atiixp [ 428.054179] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-rc1-1.g73e3f23-default #1 [ 428.072868] Hardware name: System manufacturer System Product Name/KGP(M)E-D16, BIOS 0902 12/03/2010 [ 428.094755] task: ffffffffa2c0d500 task.stack: ffffffffa2c00000 [ 428.109717] RIP: 0010:[] [] tty_wakeup+0xc/0x70 [ 428.128407] RSP: 0018:ffff9a1a5fc03df8 EFLAGS: 00010086 [ 428.142184] RAX: ffff9a1857258000 RBX: ffffffffa3050ea0 RCX: 0000000000000000 [ 428.159649] RDX: 000000000000001b RSI: 0000000000000000 RDI: 0000000000000000 [ 428.177109] RBP: ffff9a1a5fc03e08 R08: 0000000000000000 R09: 0000000000000000 [ 428.194547] R10: 0000000000021c77 R11: 0000000000000000 R12: ffff9a1857258000 [ 428.212002] R13: 0000000000000000 R14: 0000000000000020 R15: 0000000000000020 [ 428.229481] FS: 0000000000000000(0000) GS:ffff9a1a5fc00000(0000) knlGS:0000000000000000 [ 428.248938] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 428.263726] CR2: 00000000000001e0 CR3: 0000000390c06000 CR4: 00000000000006f0 [ 428.281331] Stack: [ 428.288696] ffffffffa3050ea0 ffff9a1857258000 ffff9a1a5fc03e18 ffffffffa24e0ab1 [ 428.307064] ffff9a1a5fc03e40 ffffffffa24e8865 ffffffffa3050ea0 00000000000000c2 [ 428.325456] 0000000000000046 ffff9a1a5fc03e78 ffffffffa24e8a5f ffffffffa3050ea0 [ 428.343905] Call Trace: [ 428.352319] [ 428.356216] [] uart_write_wakeup+0x21/0x30 The problem is for console ports, the serial port is not shutdown and interrupts may fire after the struct tty is gone. Simply calling the tty_port helper tty_port_tty_wakeup instead of tty_wakeup directly will ensure there is a valid struct tty. Fixes: 761ed4a94582ab29 ("tty: serial_core: convert uart_close to use tty_port_close") Reported-by: Borislav Petkov Reported-by: Mike Galbraith Cc: Jiri Slaby Cc: Greg Kroah-Hartman Cc: linux-serial@vger.kernel.org Signed-off-by: Rob Herring Signed-off-by: Greg Kroah-Hartman

tty: serial_core: Fix serial console crash on port shutdown

2016-10-28T12:13:07Z

The port->console flag is always false, as uart_console() is called before the serial console has been registered. Hence for a serial port used as the console, uart_tty_port_shutdown() will still be called when userspace closes the port, powering it down. This may lead to a system lock up when the serial console driver writes to the serial port's registers. To fix this, move the setting of port->console after the call to uart_configure_port(), which registers the serial console. Fixes: 761ed4a94582ab29 ("tty: serial_core: convert uart_close to use tty_port_close") Reported-by: Niklas Söderlund Signed-off-by: Geert Uytterhoeven Acked-by: Rob Herring Tested-by: Mugunthan V N Tested-by: Niklas Söderlund [robh: rebased on tty-linus] Signed-off-by: Rob Herring Signed-off-by: Greg Kroah-Hartman

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

2016-10-28T12:10:48Z

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 Cc: #4.4+ (beware, missing atmel_port variable) 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 Acked-by: Nicolas Ferre Signed-off-by: Greg Kroah-Hartman