From 9d86719f8769244dc99b8cb6091c41eae3fd684f Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Mon, 8 May 2023 14:19:02 +0300 Subject: [PATCH] serial: 8250: Allow using ports higher than SERIAL_8250_RUNTIME_UARTS We already allocate CONFIG_SERIAL_8250_NR_UARTS, but only allow using CONFIG_SERIAL_8250_RUNTIME_UARTS uarts unless nr_uarts module params is set. This causes issues for using distro kernels on SoCs with a large number of serial ports. Let's allow up to CONFIG_SERIAL_8250_NR_UARTS instead. To do this, we init the ports as needed if the initial uarts was too low. This way there's no need to set the value for CONFIG_SERIAL_8250_RUNTIME_UARTS to some SoC specific higher value. Typically the default value of 4 can be used as set for legacy reasons. Note that limiting the number of intial uarts still works as before unless a serial console on a higher port is specified. In this case we will increase the nr_ports up to the console port specified. Suggested-by: Andrew Davis Signed-off-by: Tony Lindgren Link: https://lore.kernel.org/r/20230508111903.39339-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_core.c | 86 +++++++++++++++++++++++++++---------- 1 file changed, 63 insertions(+), 23 deletions(-) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 13bf535..560a359 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -488,6 +488,34 @@ static inline void serial8250_apply_quirks(struct uart_8250_port *up) up->port.quirks |= skip_txen_test ? UPQ_NO_TXEN_TEST : 0; } +static struct uart_8250_port *serial8250_setup_port(int index) +{ + struct uart_8250_port *up; + + if (index >= UART_NR) + return NULL; + + up = &serial8250_ports[index]; + up->port.line = index; + + serial8250_init_port(up); + if (!base_ops) + base_ops = up->port.ops; + up->port.ops = &univ8250_port_ops; + + timer_setup(&up->timer, serial8250_timeout, 0); + + up->ops = &univ8250_driver_ops; + + if (IS_ENABLED(CONFIG_ALPHA_JENSEN) || + (IS_ENABLED(CONFIG_ALPHA_GENERIC) && alpha_jensen())) + up->port.set_mctrl = alpha_jensen_set_mctrl; + + serial8250_set_defaults(up); + + return up; +} + static void __init serial8250_isa_init_ports(void) { struct uart_8250_port *up; @@ -501,26 +529,13 @@ static void __init serial8250_isa_init_ports(void) if (nr_uarts > UART_NR) nr_uarts = UART_NR; - for (i = 0; i < nr_uarts; i++) { - struct uart_8250_port *up = &serial8250_ports[i]; - struct uart_port *port = &up->port; - - port->line = i; - serial8250_init_port(up); - if (!base_ops) - base_ops = port->ops; - port->ops = &univ8250_port_ops; - - timer_setup(&up->timer, serial8250_timeout, 0); - - up->ops = &univ8250_driver_ops; - - if (IS_ENABLED(CONFIG_ALPHA_JENSEN) || - (IS_ENABLED(CONFIG_ALPHA_GENERIC) && alpha_jensen())) - port->set_mctrl = alpha_jensen_set_mctrl; - - serial8250_set_defaults(up); - } + /* + * Set up initial isa ports based on nr_uart module param, or else + * default to CONFIG_SERIAL_8250_RUNTIME_UARTS. Note that we do not + * need to increase nr_uarts when setting up the initial isa ports. + */ + for (i = 0; i < nr_uarts; i++) + serial8250_setup_port(i); /* chain base port ops to support Remote Supervisor Adapter */ univ8250_port_ops = *base_ops; @@ -586,16 +601,29 @@ static void univ8250_console_write(struct console *co, const char *s, static int univ8250_console_setup(struct console *co, char *options) { + struct uart_8250_port *up; struct uart_port *port; - int retval; + int retval, i; /* * Check whether an invalid uart number has been specified, and * 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; + + /* + * If the console is past the initial isa ports, init more ports up to + * co->index as needed and increment nr_uarts accordingly. + */ + for (i = nr_uarts; i <= co->index; i++) { + up = serial8250_setup_port(i); + if (!up) + return -ENODEV; + nr_uarts++; + } + port = &serial8250_ports[co->index].port; /* link port to console */ port->cons = co; @@ -990,7 +1018,18 @@ int serial8250_register_8250_port(const struct uart_8250_port *up) mutex_lock(&serial_mutex); uart = serial8250_find_match_or_unused(&up->port); - if (uart && uart->port.type != PORT_8250_CIR) { + if (!uart) { + /* + * If the port is past the initial isa ports, initialize a new + * port and increment nr_uarts accordingly. + */ + uart = serial8250_setup_port(nr_uarts); + if (!uart) + goto unlock; + nr_uarts++; + } + + if (uart->port.type != PORT_8250_CIR) { struct mctrl_gpios *gpios; if (uart->port.dev) @@ -1120,6 +1159,7 @@ int serial8250_register_8250_port(const struct uart_8250_port *up) } } +unlock: mutex_unlock(&serial_mutex); return ret; -- 2.7.4