kernel/linux.git/drivers/tty/serial/serial_port.c, branch linux-7.0.y

serial: port: Make ->iotype validation global in __uart_read_properties()

2025-02-04T13:44:44+00:00

In order to make code robust against potential changes in the future move ->iotype validation outside of switch in __uart_read_properties(). If any code will be added in between that might leave the ->iotype value unknown the validation catches this up. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250124161530.398361-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: port: Always update ->iotype in __uart_read_properties()

2025-02-04T13:44:41+00:00

The documentation of the __uart_read_properties() states that ->iotype member is always altered after the function call, but the code doesn't do that in the case when use_defaults == false and the value of reg-io-width is unsupported. Make sure the code follows the documentation. Note, the current users of the uart_read_and_validate_port_properties() will fail and the change doesn't affect their behaviour, neither users of uart_read_port_properties() will be affected since the alteration happens there even in the current code flow. Fixes: e894b6005dce ("serial: port: Introduce a common helper to read properties") Cc: stable Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250124161530.398361-3-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: port: Assign ->iotype correctly when ->iobase is set

2025-02-04T13:44:35+00:00

Currently the ->iotype is always assigned to the UPIO_MEM when the respective property is not found. However, this will not support the cases when user wants to have UPIO_PORT to be set or preserved. Support this scenario by checking ->iobase value and default the ->iotype respectively. Fixes: 1117a6fdc7c1 ("serial: 8250_of: Switch to use uart_read_port_properties()") Fixes: e894b6005dce ("serial: port: Introduce a common helper to read properties") Cc: stable Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250124161530.398361-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: port: Don't block system suspend even if bytes are left to xmit

2024-06-04T12:09:47+00:00

Recently, suspend testing on sc7180-trogdor based devices has started to sometimes fail with messages like this: port a88000.serial:0.0: PM: calling pm_runtime_force_suspend+0x0/0xf8 @ 28934, parent: a88000.serial:0 port a88000.serial:0.0: PM: dpm_run_callback(): pm_runtime_force_suspend+0x0/0xf8 returns -16 port a88000.serial:0.0: PM: pm_runtime_force_suspend+0x0/0xf8 returned -16 after 33 usecs port a88000.serial:0.0: PM: failed to suspend: error -16 I could reproduce these problems by logging in via an agetty on the debug serial port (which was _not_ used for kernel console) and running: cat /var/log/messages ...and then (via an SSH session) forcing a few suspend/resume cycles. Tracing through the code and doing some printf()-based debugging shows that the -16 (-EBUSY) comes from the recently added serial_port_runtime_suspend(). The idea of the serial_port_runtime_suspend() function is to prevent the port from being _runtime_ suspended if it still has bytes left to transmit. Having bytes left to transmit isn't a reason to block _system_ suspend, though. If a serdev device in the kernel needs to block system suspend it should block its own suspend and it can use serdev_device_wait_until_sent() to ensure bytes are sent. The DEFINE_RUNTIME_DEV_PM_OPS() used by the serial_port code means that the system suspend function will be pm_runtime_force_suspend(). In pm_runtime_force_suspend() we can see that before calling the runtime suspend function we'll call pm_runtime_disable(). This should be a reliable way to detect that we're called from system suspend and that we shouldn't look for busyness. Fixes: 43066e32227e ("serial: port: Don't suspend if the port is still busy") Cc: stable@vger.kernel.org Reviewed-by: Tony Lindgren Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20240531080914.v3.1.I2395e66cf70c6e67d774c56943825c289b9c13e4@changeid Signed-off-by: Greg Kroah-Hartman

Merge 6.9-rc5 into tty-next

2024-04-23T11:24:45+00:00

We want the tty fixes in here as well, and it resolves a merge conflict in: drivers/tty/serial/serial_core.c as well. Signed-off-by: Greg Kroah-Hartman

serial: port: Add support of PNP IRQ to __uart_read_properties()

2024-04-17T11:14:30+00:00

The function __uart_read_properties doesn't cover PNP devices, so add IRQ processing for PNP devices in the branch. Signed-off-by: Guanbing Huang Suggested-by: Andy Shevchenko Reviewed-by: Andy Shevchenko Reviewed-by: Bing Fan Tested-by: Linheng Du Link: https://lore.kernel.org/r/7f4ca31ef1cab4c6ecad22fafd82117686b696be.1713234515.git.albanhuang@tencent.com Signed-off-by: Greg Kroah-Hartman

serial: core: Fix missing shutdown and startup for serial base port

2024-04-11T12:21:11+00:00

We are seeing start_tx being called after port shutdown as noted by Jiri. This happens because we are missing the startup and shutdown related functions for the serial base port. Let's fix the issue by adding startup and shutdown functions for the serial base port to block tx flushing for the serial base port when the port is not in use. Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Cc: stable Reported-by: Jiri Slaby Signed-off-by: Tony Lindgren Link: https://lore.kernel.org/r/20240411055848.38190-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman

tty: serial: switch from circ_buf to kfifo

2024-04-09T13:28:03+00:00

Switch from struct circ_buf to proper kfifo. kfifo provides much better API, esp. when wrap-around of the buffer needs to be taken into account. Look at pl011_dma_tx_refill() or cpm_uart_tx_pump() changes for example. Kfifo API can also fill in scatter-gather DMA structures, so it easier for that use case too. Look at lpuart_dma_tx() for example. Note that not all drivers can be converted to that (like atmel_serial), they handle DMA specially. Note that usb-serial uses kfifo for TX for ages. omap needed a bit more care as it needs to put a char into FIFO to start the DMA transfer when OMAP_DMA_TX_KICK is set. In that case, we have to do kfifo_dma_out_prepare twice: once to find out the tx_size (to find out if it is worths to do DMA at all -- size >= 4), the second time for the actual transfer. All traces of circ_buf are removed from serial_core.h (and its struct uart_state). Signed-off-by: Jiri Slaby (SUSE) Cc: Al Cooper Cc: Matthias Brugger Cc: AngeloGioacchino Del Regno Cc: Kumaravel Thiagarajan Cc: Tharun Kumar P Cc: Russell King Cc: Vineet Gupta Cc: Richard Genoud Cc: Nicolas Ferre Cc: Alexandre Belloni Cc: Claudiu Beznea Cc: Alexander Shiyan Cc: Baruch Siach Cc: Maciej W. Rozycki Cc: Shawn Guo Cc: Sascha Hauer Cc: Fabio Estevam Cc: Neil Armstrong Cc: Kevin Hilman Cc: Jerome Brunet Cc: Martin Blumenstingl Cc: Taichi Sugaya Cc: Takao Orito Cc: Bjorn Andersson Cc: Konrad Dybcio Cc: Pali Rohár Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Aneesh Kumar K.V Cc: Naveen N. Rao Cc: Manivannan Sadhasivam Cc: Krzysztof Kozlowski Cc: Alim Akhtar Cc: Laxman Dewangan Cc: Thierry Reding Cc: Jonathan Hunter Cc: Orson Zhai Cc: Baolin Wang Cc: Chunyan Zhang Cc: Patrice Chotard Cc: Maxime Coquelin Cc: Alexandre Torgue Cc: David S. Miller Cc: Hammer Hsieh Cc: Peter Korsgaard Cc: Timur Tabi Cc: Michal Simek Cc: Sumit Semwal Cc: Christian König Link: https://lore.kernel.org/r/20240405060826.2521-13-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

Merge tag 'tty-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2024-03-21T19:44:10+00:00

Pull tty / serial driver updates from Greg KH: "Here is the big set of TTY/Serial driver updates and cleanups for 6.9-rc1. Included in here are: - more tty cleanups from Jiri - loads of 8250 driver cleanups from Andy - max310x driver updates - samsung serial driver updates - uart_prepare_sysrq_char() updates for many drivers - platform driver remove callback void cleanups - stm32 driver updates - other small tty/serial driver updates All of these have been in linux-next for a long time with no reported issues" * tag 'tty-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (199 commits) dt-bindings: serial: stm32: add power-domains property serial: 8250_dw: Replace ACPI device check by a quirk serial: Lock console when calling into driver before registration serial: 8250_uniphier: Switch to use uart_read_port_properties() serial: 8250_tegra: Switch to use uart_read_port_properties() serial: 8250_pxa: Switch to use uart_read_port_properties() serial: 8250_omap: Switch to use uart_read_port_properties() serial: 8250_of: Switch to use uart_read_port_properties() serial: 8250_lpc18xx: Switch to use uart_read_port_properties() serial: 8250_ingenic: Switch to use uart_read_port_properties() serial: 8250_dw: Switch to use uart_read_port_properties() serial: 8250_bcm7271: Switch to use uart_read_port_properties() serial: 8250_bcm2835aux: Switch to use uart_read_port_properties() serial: 8250_aspeed_vuart: Switch to use uart_read_port_properties() serial: port: Introduce a common helper to read properties serial: core: Add UPIO_UNKNOWN constant for unknown port type serial: core: Move struct uart_port::quirks closer to possible values serial: sh-sci: Call sci_serial_{in,out}() directly serial: core: only stop transmit when HW fifo is empty serial: pch: Use uart_prepare_sysrq_char(). ...

serial: port: Introduce a common helper to read properties

2024-03-05T13:38:28+00:00

Several serial drivers want to read the same or similar set of the port properties. Make a common helper for them. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20240304123035.758700-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman