Re: [PATCH tty v1 29/74] serial: imx: Use port lock wrappers

[Uwe Kleine-König]

On Thu, Sep 14, 2023 at 08:43:46PM +0206, John Ogness wrote:
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> 
> 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 <tglx@xxxxxxxxxxxxx>

This lacks a Signed-off line by John.

Otherwise looks fine to me.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

Attachment: signature.asc
Description: PGP signature