kernel.git/drivers/tty/serial/8250, branch linux-4.20.y

serial: 8250_pci: Make PCI class test non fatal

2019-02-12T19:02:38Z

commit 824d17c57b0abbcb9128fb3f7327fae14761914b upstream. As has been reported the National Instruments serial cards have broken PCI class. The commit 7d8905d06405 ("serial: 8250_pci: Enable device after we check black list") made the PCI class check mandatory for the case when device is listed in a quirk list. Make PCI class test non fatal to allow broken card be enumerated. Fixes: 7d8905d06405 ("serial: 8250_pci: Enable device after we check black list") Cc: stable Reported-by: Guan Yung Tseng Tested-by: Guan Yung Tseng Tested-by: KHUENY.Gerhard Signed-off-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman

Revert "serial: 8250: Fix clearing FIFOs in RS485 mode again"

2018-12-17T15:18:29Z

Commit f6aa5beb45be ("serial: 8250: Fix clearing FIFOs in RS485 mode again") makes a change to FIFO clearing code which its commit message suggests was intended to be specific to use with RS485 mode, however: 1) The change made does not just affect __do_stop_tx_rs485(), it also affects other uses of serial8250_clear_fifos() including paths for starting up, shutting down or auto-configuring a port regardless of whether it's an RS485 port or not. 2) It makes the assumption that resetting the FIFOs is a no-op when FIFOs are disabled, and as such it checks for this case & explicitly avoids setting the FIFO reset bits when the FIFO enable bit is clear. A reading of the PC16550D manual would suggest that this is OK since the FIFO should automatically be reset if it is later enabled, but we support many 16550-compatible devices and have never required this auto-reset behaviour for at least the whole git era. Starting to rely on it now seems risky, offers no benefit, and indeed breaks at least the Ingenic JZ4780's UARTs which reads garbage when the RX FIFO is enabled if we don't explicitly reset it. 3) By only resetting the FIFOs if they're enabled, the behaviour of serial8250_do_startup() during boot now depends on what the value of FCR is before the 8250 driver is probed. This in itself seems questionable and leaves us with FCR=0 & no FIFO reset if the UART was used by 8250_early, otherwise it depends upon what the bootloader left behind. 4) Although the naming of serial8250_clear_fifos() may be unclear, it is clear that callers of it expect that it will disable FIFOs. Both serial8250_do_startup() & serial8250_do_shutdown() contain comments to that effect, and other callers explicitly re-enable the FIFOs after calling serial8250_clear_fifos(). The premise of that patch that disabling the FIFOs is incorrect therefore seems wrong. For these reasons, this reverts commit f6aa5beb45be ("serial: 8250: Fix clearing FIFOs in RS485 mode again"). Signed-off-by: Paul Burton Fixes: f6aa5beb45be ("serial: 8250: Fix clearing FIFOs in RS485 mode again"). Cc: Greg Kroah-Hartman Cc: Daniel Jedrychowski Cc: Marek Vasut Cc: linux-mips@vger.kernel.org Cc: linux-serial@vger.kernel.org Cc: stable # 4.10+ Signed-off-by: Greg Kroah-Hartman

tty: serial: 8250_mtk: always resume the device in probe.

2018-12-05T10:31:21Z

serial8250_register_8250_port calls uart_config_port, which calls config_port on the port before it tries to power on the port. So we need the port to be on before calling serial8250_register_8250_port. Change the code to always do a runtime resume in probe before registering port, and always do a runtime suspend in remove. This basically reverts the change in commit 68e5fc4a255a ("tty: serial: 8250_mtk: use pm_runtime callbacks for enabling"), but still use pm_runtime callbacks. Fixes: 68e5fc4a255a ("tty: serial: 8250_mtk: use pm_runtime callbacks for enabling") Signed-off-by: Peter Shih Cc: stable Signed-off-by: Greg Kroah-Hartman

Merge 4.19-rc7 into tty-next

2018-10-08T13:43:12Z

We want the fixes in here as well. Signed-off-by: Greg Kroah-Hartman

Revert "serial: 8250_dw: Fix runtime PM handling"

2018-10-02T21:35:10Z

This reverts commit d76c74387e1c978b6c5524a146ab0f3f72206f98. While commit d76c74387e1c ("serial: 8250_dw: Fix runtime PM handling") fixes runtime PM handling when using kgdb, it introduces a traceback for everyone else. BUG: sleeping function called from invalid context at /mnt/host/source/src/third_party/kernel/next/drivers/base/power/runtime.c:1034 in_atomic(): 1, irqs_disabled(): 1, pid: 1, name: swapper/0 7 locks held by swapper/0/1: #0: 000000005ec5bc72 (&dev->mutex){....}, at: __driver_attach+0xb5/0x12b #1: 000000005d5fa9e5 (&dev->mutex){....}, at: __device_attach+0x3e/0x15b #2: 0000000047e93286 (serial_mutex){+.+.}, at: serial8250_register_8250_port+0x51/0x8bb #3: 000000003b328f07 (port_mutex){+.+.}, at: uart_add_one_port+0xab/0x8b0 #4: 00000000fa313d4d (&port->mutex){+.+.}, at: uart_add_one_port+0xcc/0x8b0 #5: 00000000090983ca (console_lock){+.+.}, at: vprintk_emit+0xdb/0x217 #6: 00000000c743e583 (console_owner){-...}, at: console_unlock+0x211/0x60f irq event stamp: 735222 __down_trylock_console_sem+0x4a/0x84 console_unlock+0x338/0x60f __do_softirq+0x4a4/0x50d irq_exit+0x64/0xe2 CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc5 #6 Hardware name: Google Caroline/Caroline, BIOS Google_Caroline.7820.286.0 03/15/2017 Call Trace: dump_stack+0x7d/0xbd ___might_sleep+0x238/0x259 __pm_runtime_resume+0x4e/0xa4 ? serial8250_rpm_get+0x2e/0x44 serial8250_console_write+0x44/0x301 ? lock_acquire+0x1b8/0x1fa console_unlock+0x577/0x60f vprintk_emit+0x1f0/0x217 printk+0x52/0x6e register_console+0x43b/0x524 uart_add_one_port+0x672/0x8b0 ? set_io_from_upio+0x150/0x162 serial8250_register_8250_port+0x825/0x8bb dw8250_probe+0x80c/0x8b0 ? dw8250_serial_inq+0x8e/0x8e ? dw8250_check_lcr+0x108/0x108 ? dw8250_runtime_resume+0x5b/0x5b ? dw8250_serial_outq+0xa1/0xa1 ? dw8250_remove+0x115/0x115 platform_drv_probe+0x76/0xc5 really_probe+0x1f1/0x3ee ? driver_allows_async_probing+0x5d/0x5d driver_probe_device+0xd6/0x112 ? driver_allows_async_probing+0x5d/0x5d bus_for_each_drv+0xbe/0xe5 __device_attach+0xdd/0x15b bus_probe_device+0x5a/0x10b device_add+0x501/0x894 ? _raw_write_unlock+0x27/0x3a platform_device_add+0x224/0x2b7 mfd_add_device+0x718/0x75b ? __kmalloc+0x144/0x16a ? mfd_add_devices+0x38/0xdb mfd_add_devices+0x9b/0xdb intel_lpss_probe+0x7d4/0x8ee intel_lpss_pci_probe+0xac/0xd4 pci_device_probe+0x101/0x18e ... Revert the offending patch until a more comprehensive solution is available. Cc: Tony Lindgren Cc: Andy Shevchenko Cc: Phil Edworthy Fixes: d76c74387e1c ("serial: 8250_dw: Fix runtime PM handling") Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

serial: 8250_uniphier: add auto-flow-control support

2018-10-02T20:38:58Z

Add selective auto-flow-control support for UniPhier serial driver. Signed-off-by: Dai Okamura Signed-off-by: Masahiro Yamada Reviewed-by: Rob Herring Signed-off-by: Greg Kroah-Hartman

serial: 8250_uniphier: flatten probe function

2018-10-02T20:38:58Z

Currently, the DT-related settings are split out to uniphier_of_serial_setup(), but it turned out to be not nice. The next commit will add a DT property, but it will not fit in the helper. Merge the helper into the probe function. Signed-off-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman

serial: 8250_uniphier: remove unused "fifo-size" property

2018-10-02T20:38:58Z

The FIFO size of the UART devices is 64 on almost all UniPhier SoCs with the exception Pro4TV SoC (MN2WS0235), which used 128 FIFO size. However, Pro4TV SoC was never upstreamed, and out of production. So, this property has never been used in a useful way. Let's remove old unused code. Signed-off-by: Masahiro Yamada Reviewed-by: Rob Herring Signed-off-by: Greg Kroah-Hartman

serial: 8250: Fix clearing FIFOs in RS485 mode again

2018-09-18T14:07:25Z

The 8250 FIFOs indeed need to be cleared after stopping transmission in RS485 mode without SER_RS485_RX_DURING_TX flag set. But there are two problems with the approach taken by the previous patch from Fixes tag. First, serial8250_clear_fifos() should clear fifos, but what it really does is it enables the FIFOs unconditionally if present, clears them and then sets the FCR register to zero, which effectively disables the FIFOs. In case the FIFO is disabled, enabling it and clearing it makes no sense and in fact can trigger misbehavior of the 8250 core. Moreover, the FCR register may contain other FIFO configuration bits which may not be writable unconditionally and writing them incorrectly can trigger misbehavior of the 8250 core too. (ie. AM335x UART swallows the first byte and retransmits the last byte twice because of this FCR write). Second, serial8250_clear_and_reinit_fifos() completely reloads the FCR, but what really has to happen at the end of the RS485 transmission is clearing of the FIFOs and nothing else. This patch repairs serial8250_clear_fifos() so that it really only clears the FIFOs by operating on FCR[2:1] bits and leaves all the other bits alone. It also undoes serial8250_clear_and_reinit_fifos() from __do_stop_tx_rs485() as serial8250_clear_fifos() is sufficient. Signed-off-by: Marek Vasut Fixes: 2bed8a8e7072 ("Clearing FIFOs in RS485 emulation mode causes subsequent transmits to break") Cc: Daniel Jedrychowski Cc: Greg Kroah-Hartman Cc: stable # let it bake a bit before merging Signed-off-by: Greg Kroah-Hartman

serial: 8250_of: Fix for lack of interrupt support

2018-09-18T14:07:25Z

In commit c58caaab3bf8 ("serial: 8250: of: Defer probe on missing IRQ"), a check was added for the UART driver being probed prior to the parent IRQ controller. Unfortunately this breaks certain boards which have no interrupt support, like Huawei D03. Indeed, the 8250 DT bindings state that interrupts should be supported - not must. To fix, switch from irq_of_parse_and_map() to of_irq_get(), which does relay whether the IRQ host controller domain is not ready, i.e. defer probe, instead of assuming it. Fixes: c58caaab3bf8 ("serial: 8250: of: Defer probe on missing IRQ") Signed-off-by: John Garry Reviewed-by: Rob Herring Reviewed-by: Alexander Sverdlin Tested-by: Alexander Sverdlin Signed-off-by: Greg Kroah-Hartman