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

Merge 6.15-rc4 into tty-next

2025-04-28T08:13:28+00:00

We need the tty/serial fixes in here as well. Signed-off-by: Greg Kroah-Hartman

serial: sifive: lock port in startup()/shutdown() callbacks

2025-04-15T13:02:39+00:00

startup()/shutdown() callbacks access SIFIVE_SERIAL_IE_OFFS. The register is also accessed from write() callback. If console were printing and startup()/shutdown() callback gets called, its access to the register could be overwritten. Add port->lock to startup()/shutdown() callbacks to make sure their access to SIFIVE_SERIAL_IE_OFFS is synchronized against write() callback. Fixes: 45c054d0815b ("tty: serial: add driver for the SiFive UART") Signed-off-by: Ryo Takakura Reviewed-by: Petr Mladek Cc: stable@vger.kernel.org Reviewed-by: John Ogness Rule: add Link: https://lore.kernel.org/stable/20250330003522.386632-1-ryotkkr98%40gmail.com Link: https://lore.kernel.org/r/20250412001847.183221-1-ryotkkr98@gmail.com Signed-off-by: Greg Kroah-Hartman

serial: sifive: Switch to nbcon console

2025-04-15T12:37:43+00:00

Add the necessary callbacks(write_atomic, write_thread, device_lock and device_unlock) and CON_NBCON flag to switch the sifive console driver to perform as nbcon console. Both ->write_atomic() and ->write_thread() will check for console ownership whenever they are accessing registers. The ->device_lock()/unlock() will provide the additional serilization necessary for ->write_thread() which is called from dedicated printing thread. Signed-off-by: Ryo Takakura Reviewed-by: John Ogness Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20250412002544.185038-1-ryotkkr98@gmail.com Signed-off-by: Greg Kroah-Hartman

serial: Switch back to struct platform_driver::remove()

2024-10-11T06:13:28+00:00

After commit 0edb555a65d1 ("platform: Make platform_driver::remove() return void") .remove() is (again) the right callback to implement for platform drivers. Convert all platform drivers below drivers/tty/serial to use .remove(), with the eventual goal to drop struct platform_driver::remove_new(). As .remove() and .remove_new() have the same prototypes, conversion is done by just changing the structure member name in the driver initializer. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20241007205803.444994-7-u.kleine-koenig@baylibre.com Signed-off-by: Greg Kroah-Hartman

serial: sifive: Remove 0 from fu540-c000-uart0 binding.

2024-04-09T13:48:46+00:00

The driver is using "sifive,fu540-c000-uart0" as a binding. The device tree and documentation states "sifive,fu540-c000-uart" instead. This means the binding is not matched and not used. This did not cause any problems because the alternative binding, used in the device tree, "sifive,uart0" is not handling the hardware any different. Align the binding in the driver with the documentation. Signed-off-by: Sebastian Andrzej Siewior Reviewed-by: Conor Dooley Link: https://lore.kernel.org/r/20240307090950.eLELkuyK@linutronix.de Signed-off-by: Greg Kroah-Hartman

serial: sifive: Use uart_prepare_sysrq_char() to handle sysrq.

2024-03-02T21:06:21+00:00

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT. The driver splits the locking function into two parts: local_irq_save() and uart_port_lock() and this breaks PREEMPT_RT. Handle sysrq requests sysrq once the port lock is dropped. Remove the special case in the console write routine an always use the complete locking function. Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: linux-riscv@lists.infradead.org Signed-off-by: Sebastian Andrzej Siewior Link: https://lore.kernel.org/r/20240301215246.891055-13-bigeasy@linutronix.de Signed-off-by: Greg Kroah-Hartman

serial: sifive: Declare PM operations as static

2023-11-23T19:31:18+00:00

They are only used within this file, so they should have static linkage. Signed-off-by: Samuel Holland Link: https://lore.kernel.org/r/20231113023122.1185407-1-samuel.holland@sifive.com Signed-off-by: Greg Kroah-Hartman

serial: sifive: Convert to platform remove callback returning void

2023-11-23T19:12:34+00:00

The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is ignored (apart from emitting a warning) and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new(), which already returns void. Eventually after all drivers are converted, .remove_new() will be renamed to .remove(). Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König Reviewed-by: Samuel Holland Link: https://lore.kernel.org/r/20231110152927.70601-40-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman

serial: sifive: Use port lock wrappers

2023-09-18T09:18:15+00:00

When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-62-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman

serial: sifive: Add suspend and resume operations

2023-08-22T13:29:10+00:00

If the Sifive Uart is not used as the wake up source, suspend the uart before the system enter the suspend state to prevent it woken up by unexpected uart interrupt. Resume the uart once the system woken up. Signed-off-by: Nick Hu Reviewed-by: Ben Dooks Link: https://lore.kernel.org/r/20230815090216.2575971-1-nick.hu@sifive.com Signed-off-by: Greg Kroah-Hartman