Messages in this thread | | | Date | Tue, 4 Jul 2023 16:46:40 +0200 | From | neil.armstrong@linaro ... | Subject | Re: [PATCH v1 2/5] tty: serial: meson: redesign the module to platform_driver |
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On 04/07/2023 15:59, Dmitry Rokosov wrote: > Actually, the meson_uart module is already a platform_driver, but it is > currently registered manually and the uart core registration is run > outside the probe() scope, which results in some restrictions. For > instance, it is not possible to communicate with the OF subsystem > because it requires an initialized device object. > > To address this issue, apply module_platform_driver() instead of direct > module init/exit routines. Additionally, move uart_register_driver() to > the driver probe(), and destroy manual console registration because it's > already run in the uart_register_driver() flow. > > Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru> > --- > drivers/tty/serial/meson_uart.c | 46 +++++++-------------------------- > 1 file changed, 10 insertions(+), 36 deletions(-) > > diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c > index 169f028956ae..87c0eb5f2dba 100644 > --- a/drivers/tty/serial/meson_uart.c > +++ b/drivers/tty/serial/meson_uart.c > @@ -621,12 +621,6 @@ static struct console meson_serial_console = { > .data = &meson_uart_driver, > }; > > -static int __init meson_serial_console_init(void) > -{ > - register_console(&meson_serial_console); > - return 0; > -} > - > static void meson_serial_early_console_write(struct console *co, > const char *s, > u_int count) > @@ -652,9 +646,6 @@ OF_EARLYCON_DECLARE(meson, "amlogic,meson-ao-uart", > > #define MESON_SERIAL_CONSOLE (&meson_serial_console) > #else > -static int __init meson_serial_console_init(void) { > - return 0; > -} > #define MESON_SERIAL_CONSOLE NULL > #endif > > @@ -738,6 +729,13 @@ static int meson_uart_probe(struct platform_device *pdev) > if (ret) > return ret; > > + if (!meson_uart_driver.state) { > + ret = uart_register_driver(&meson_uart_driver); > + if (ret) > + return dev_err_probe(&pdev->dev, ret, > + "failed to register meson-uart driver\n"); > + }
PL010 protects this in a mutex, and I think you should do the same otherwise if multiple uart probes at the same it will do weird stuff.
> + > port->iotype = UPIO_MEM; > port->mapbase = res_mem->start; > port->mapsize = resource_size(res_mem); > @@ -776,6 +774,8 @@ static int meson_uart_remove(struct platform_device *pdev) > uart_remove_one_port(&meson_uart_driver, port); > meson_ports[pdev->id] = NULL; > > + uart_unregister_driver(&meson_uart_driver); > +
This is dangerous, it will remove the driver even if some uart are still attached to it.
You should probably do like in pl010_remove() and remove only if the last one is removed.
> return 0; > } > > @@ -809,33 +809,7 @@ static struct platform_driver meson_uart_platform_driver = { > }, > }; > > -static int __init meson_uart_init(void) > -{ > - int ret; > - > - ret = meson_serial_console_init(); > - if (ret) > - return ret; > - > - ret = uart_register_driver(&meson_uart_driver); > - if (ret) > - return ret; > - > - ret = platform_driver_register(&meson_uart_platform_driver); > - if (ret) > - uart_unregister_driver(&meson_uart_driver); > - > - return ret; > -} > - > -static void __exit meson_uart_exit(void) > -{ > - platform_driver_unregister(&meson_uart_platform_driver); > - uart_unregister_driver(&meson_uart_driver); > -} > - > -module_init(meson_uart_init); > -module_exit(meson_uart_exit); > +module_platform_driver(meson_uart_platform_driver);
Only pl010 uses this scheme, and I don't know why... if it works then it's ok for me.
Thanks, Neil
> > MODULE_AUTHOR("Carlo Caione <carlo@caione.org>"); > MODULE_DESCRIPTION("Amlogic Meson serial port driver");
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