linux/drivers/tty/serial, branch v6.14

serial: 8250: Fix fifo underflow on flush

2025-02-14T08:50:55Z

When flushing the serial port's buffer, uart_flush_buffer() calls kfifo_reset() but if there is an outstanding DMA transfer then the completion function will consume data from the kfifo via uart_xmit_advance(), underflowing and leading to ongoing DMA as the driver tries to transmit another 2^32 bytes. This is readily reproduced with serial-generic and amidi sending even short messages as closing the device on exit will wait for the fifo to drain and in the underflow case amidi hangs for 30 seconds on exit in tty_wait_until_sent(). A trace of that gives: kworker/1:1-84 [001] 51.769423: bprint: serial8250_tx_dma: tx_size=3 fifo_len=3 amidi-763 [001] 51.769460: bprint: uart_flush_buffer: resetting fifo irq/21-fe530000-76 [000] 51.769474: bprint: __dma_tx_complete: tx_size=3 irq/21-fe530000-76 [000] 51.769479: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294967293 irq/21-fe530000-76 [000] 51.781295: bprint: __dma_tx_complete: tx_size=4096 irq/21-fe530000-76 [000] 51.781301: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294963197 irq/21-fe530000-76 [000] 51.793131: bprint: __dma_tx_complete: tx_size=4096 irq/21-fe530000-76 [000] 51.793135: bprint: serial8250_tx_dma: tx_size=4096 fifo_len=4294959101 irq/21-fe530000-76 [000] 51.804949: bprint: __dma_tx_complete: tx_size=4096 Since the port lock is held in when the kfifo is reset in uart_flush_buffer() and in __dma_tx_complete(), adding a flush_buffer hook to adjust the outstanding DMA byte count is sufficient to avoid the kfifo underflow. Fixes: 9ee4b83e51f74 ("serial: 8250: Add support for dmaengine") Cc: stable Signed-off-by: John Keeping Link: https://lore.kernel.org/r/20250208124148.1189191-1-jkeeping@inmusicbrands.com Signed-off-by: Greg Kroah-Hartman

serial: 8250_pnp: Remove unneeded ->iotype assignment

2025-02-04T13:44:53Z

If ->iobase is set the default will be UPIO_PORT for ->iotype after the uart_read_and_validate_port_properties() call. Hence no need to assign that explicitly. Otherwise it will be UPIO_MEM. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250124161530.398361-7-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: 8250_platform: Remove unneeded ->iotype assignment

2025-02-04T13:44:52Z

If ->iobase is set the default will be UPIO_PORT for ->iotype after the uart_read_and_validate_port_properties() call. Hence no need to assign that explicitly. Otherwise it will be UPIO_MEM. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250124161530.398361-6-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: 8250_of: Remove unneeded ->iotype assignment

2025-02-04T13:44:50Z

If ->iobase is set the default will be UPIO_PORT for ->iotype after the uart_read_and_validate_port_properties() call. Hence no need to assign that explicitly. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250124161530.398361-5-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

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

2025-02-04T13:44:44Z

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()

2025-02-04T13:44:41Z

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

2025-02-04T13:44:35Z

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: sc16is7xx: Fix IRQ number check behavior

2025-02-04T13:42:42Z

The logical meaning of the previous version is wrong due to a typo. If the IRQ equals 0, no interrupt pin is available and polling mode shall be used. Additionally, this fix adds a check for IRQ < 0 to increase robustness, because documentation still says that negative IRQ values cannot be absolutely ruled-out. Fixes: 104c1b9dde9d ("serial: sc16is7xx: Add polling mode if no IRQ pin is available") Signed-off-by: Andre Werner Reviewed-by: Jiri Slaby Reviewed-by: Andy Shevchenko Reviewed-by: Maarten Brock Reviewed-by: Hugo Villeneuve Link: https://lore.kernel.org/r/20250121071819.1346672-1-andre.werner@systec-electronic.com Signed-off-by: Greg Kroah-Hartman

Merge tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2025-01-28T20:25:12Z

Pull driver core and debugfs updates from Greg KH: "Here is the big set of driver core and debugfs updates for 6.14-rc1. Included in here is a bunch of driver core, PCI, OF, and platform rust bindings (all acked by the different subsystem maintainers), hence the merge conflict with the rust tree, and some driver core api updates to mark things as const, which will also require some fixups due to new stuff coming in through other trees in this merge window. There are also a bunch of debugfs updates from Al, and there is at least one user that does have a regression with these, but Al is working on tracking down the fix for it. In my use (and everyone else's linux-next use), it does not seem like a big issue at the moment. Here's a short list of the things in here: - driver core rust bindings for PCI, platform, OF, and some i/o functions. We are almost at the "write a real driver in rust" stage now, depending on what you want to do. - misc device rust bindings and a sample driver to show how to use them - debugfs cleanups in the fs as well as the users of the fs api for places where drivers got it wrong or were unnecessarily doing things in complex ways. - driver core const work, making more of the api take const * for different parameters to make the rust bindings easier overall. - other small fixes and updates All of these have been in linux-next with all of the aforementioned merge conflicts, and the one debugfs issue, which looks to be resolved "soon"" * tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (95 commits) rust: device: Use as_char_ptr() to avoid explicit cast rust: device: Replace CString with CStr in property_present() devcoredump: Constify 'struct bin_attribute' devcoredump: Define 'struct bin_attribute' through macro rust: device: Add property_present() saner replacement for debugfs_rename() orangefs-debugfs: don't mess with ->d_name octeontx2: don't mess with ->d_parent or ->d_parent->d_name arm_scmi: don't mess with ->d_parent->d_name slub: don't mess with ->d_name sof-client-ipc-flood-test: don't mess with ->d_name qat: don't mess with ->d_name xhci: don't mess with ->d_iname mtu3: don't mess wiht ->d_iname greybus/camera - stop messing with ->d_iname mediatek: stop messing with ->d_iname netdevsim: don't embed file_operations into your structs b43legacy: make use of debugfs_get_aux() b43: stop embedding struct file_operations into their objects carl9170: stop embedding file_operations into their objects ...

Revert "serial: 8250: Switch to nbcon console"

2025-01-22T09:35:56Z

This reverts commit b63e6f60eab45b16a1bf734fef9035a4c4187cd5. kernel test robot has found problems with this commit so revert it for now. Link: https://lore.kernel.org/r/202501221029.fb0d574d-lkp@intel.com Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202501221029.fb0d574d-lkp@intel.com Cc: John Ogness Cc: Petr Mladek Signed-off-by: Greg Kroah-Hartman