From cfcec52e9781f08948c6eb98198d65c45be75a70 Mon Sep 17 00:00:00 2001 From: Karthik Manamcheri Date: Thu, 28 Mar 2013 17:33:20 -0500 Subject: [PATCH] serial: 8250: Make SERIAL_8250_RUNTIME_UARTS work correctly Consider a situation where I have an ARM based system and therefore no legacy ports. Say, I have two memory-mapped ports. I use device tree to describe the ports. What would be the config options I set so that I get only the two ports in my system? I do not want legacy ports being created automatically and I want it to be flexible enough that it creates the devices based only on the device tree. I expected setting SERIAL_8250_RUNTIME_UARTS = 0 to work because the description said, "Set this to the maximum number of serial ports you want the kernel to register at boot time." Unfortunately, even though SERIAL_8250_NR_UARTS was set to the default value of 4, I did not get any device nodes (because SERIAL_8250_RUNTIME_UARTS was 0). This is what this change is addressing. SERIAL_8250_NR_UARTS controls the maximum number of ports you can support. SERIAL_8250_RUNTIME_UARTS specifies the number of ports you want to create automatically for legacy ports at boot time. All other ports will be created when serial8250_register_port is called (and if does not exceed the total number of supported ports as specified by SERIAL_8250_NR_UARTS). Signed-off-by: Karthik Manamcheri Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c index 19ebbdf43106..e5ddfd6fc468 100644 --- a/drivers/tty/serial/8250/8250.c +++ b/drivers/tty/serial/8250/8250.c @@ -2755,7 +2755,7 @@ static void __init serial8250_isa_init_ports(void) if (nr_uarts > UART_NR) nr_uarts = UART_NR; - for (i = 0; i < nr_uarts; i++) { + for (i = 0; i < UART_NR; i++) { struct uart_8250_port *up = &serial8250_ports[i]; struct uart_port *port = &up->port; @@ -2916,7 +2916,7 @@ static int __init serial8250_console_setup(struct console *co, char *options) * if so, search for the first available port that does have * console support. */ - if (co->index >= nr_uarts) + if (co->index >= UART_NR) co->index = 0; port = &serial8250_ports[co->index].port; if (!port->iobase && !port->membase) @@ -2957,7 +2957,7 @@ int serial8250_find_port(struct uart_port *p) int line; struct uart_port *port; - for (line = 0; line < nr_uarts; line++) { + for (line = 0; line < UART_NR; line++) { port = &serial8250_ports[line].port; if (uart_match_port(p, port)) return line; @@ -3110,7 +3110,7 @@ static int serial8250_remove(struct platform_device *dev) { int i; - for (i = 0; i < nr_uarts; i++) { + for (i = 0; i < UART_NR; i++) { struct uart_8250_port *up = &serial8250_ports[i]; if (up->port.dev == &dev->dev) @@ -3178,7 +3178,7 @@ static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port * /* * First, find a port entry which matches. */ - for (i = 0; i < nr_uarts; i++) + for (i = 0; i < UART_NR; i++) if (uart_match_port(&serial8250_ports[i].port, port)) return &serial8250_ports[i]; @@ -3187,7 +3187,7 @@ static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port * * free entry. We look for one which hasn't been previously * used (indicated by zero iobase). */ - for (i = 0; i < nr_uarts; i++) + for (i = 0; i < UART_NR; i++) if (serial8250_ports[i].port.type == PORT_UNKNOWN && serial8250_ports[i].port.iobase == 0) return &serial8250_ports[i]; @@ -3196,7 +3196,7 @@ static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port * * That also failed. Last resort is to find any entry which * doesn't have a real port associated with it. */ - for (i = 0; i < nr_uarts; i++) + for (i = 0; i < UART_NR; i++) if (serial8250_ports[i].port.type == PORT_UNKNOWN) return &serial8250_ports[i]; -- 2.20.1