From ae14a7954f5124208e6e93cafb3099f83acd43f5 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Fri, 5 Sep 2014 21:02:36 +0200 Subject: [PATCH] tty: serial: 8250_core: provide a function to export uart_8250_port There is no way to access a struct uart_8250_port for a specific line. This is only required outside of the 8250/uart callbacks like for devices' suspend & remove callbacks. For those the 8250-core provides a wrapper like serial8250_unregister_port() which passes the struct to the proper function based on the line argument. For run time suspend I need access to this struct not only to make serial_out() work but also to properly restore up->ier and up->mcr. Acked-by: Alan Cox Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250.h | 2 ++ drivers/tty/serial/8250/8250_core.c | 18 ++++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index 1b08c918cd51..85bfec58d77c 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -112,6 +112,8 @@ static inline void serial_dl_write(struct uart_8250_port *up, int value) up->dl_write(up, value); } +struct uart_8250_port *serial8250_get_port(int line); + #if defined(__alpha__) && !defined(CONFIG_PCI) /* * Digital did something really horribly wrong with the OUT1 and OUT2 diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index b597e730b9e7..90e0d5e2b7ee 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -2916,6 +2916,24 @@ static struct uart_ops serial8250_pops = { static struct uart_8250_port serial8250_ports[UART_NR]; +/** + * serial8250_get_port - retrieve struct uart_8250_port + * @line: serial line number + * + * This function retrieves struct uart_8250_port for the specific line. + * This struct *must* *not* be used to perform a 8250 or serial core operation + * which is not accessible otherwise. Its only purpose is to make the struct + * accessible to the runtime-pm callbacks for context suspend/restore. + * The lock assumption made here is none because runtime-pm suspend/resume + * callbacks should not be invoked if there is any operation performed on the + * port. + */ +struct uart_8250_port *serial8250_get_port(int line) +{ + return &serial8250_ports[line]; +} +EXPORT_SYMBOL_GPL(serial8250_get_port); + static void (*serial8250_isa_config)(int port, struct uart_port *up, unsigned short *capabilities);