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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 <alan@linux.intel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sebastian Andrzej Siewior 2014-09-05 21:02:36 +02:00 committed by Greg Kroah-Hartman
parent 9d329c1c68
commit ae14a7954f
2 changed files with 20 additions and 0 deletions
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2
drivers/tty/serial/8250/8250.h
View File

@ -112,6 +112,8 @@ static inline void serial_dl_write(struct uart_8250_port *up, int value)
up->dl_write(up, value); up->dl_write(up, value);
} }
struct uart_8250_port *serial8250_get_port(int line);
#if defined(__alpha__) && !defined(CONFIG_PCI) #if defined(__alpha__) && !defined(CONFIG_PCI)
/* /*
* Digital did something really horribly wrong with the OUT1 and OUT2 * Digital did something really horribly wrong with the OUT1 and OUT2

18
drivers/tty/serial/8250/8250_core.c
View File

@ -2916,6 +2916,24 @@ static struct uart_ops serial8250_pops = {
static struct uart_8250_port serial8250_ports[UART_NR]; 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, static void (*serial8250_isa_config)(int port, struct uart_port *up,
unsigned short *capabilities); unsigned short *capabilities);