[PATCH 1/5] tty: serial: 8250 core: provide a function to export uart_8250_port
From: bigeasy@linutronix.de (Sebastian Andrzej Siewior)
Date: 2014-07-16 14:45:31
Also in:
linux-omap, linux-serial, lkml
Subsystem:
8250/16?50 (and clone uarts) serial driver, the rest, tty layer and serial drivers · Maintainers:
Greg Kroah-Hartman, Linus Torvalds, Jiri Slaby
There is no access 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 wrapper like serial8250_unregister_port() which passes the struct to the proper function based on the line argument. For runtime 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 <redacted> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- 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 1ebf853..34c3cd1 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h@@ -110,6 +110,8 @@ 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 7a91c6d..5a6af19 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c@@ -2755,6 +2755,24 @@ 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);
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2.0.1