Add a hook for `uart_report_port' to let serial ports report extra
properties beyond `irq' and `base_baud'. Use it with the 8250 backend
to report extra baud rates supported above the base rate for ports with
the UPF_MAGIC_MULTIPLIER property, so that people have a way to find out
that they are supported with their system, e.g.:
Serial: 8250/16550 driver, 5 ports, IRQ sharing enabled
printk: console [ttyS0] disabled
serial8250.0: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200 [+230400, 460800]) is a 16550A
printk: console [ttyS0] enabled
printk: console [ttyS0] enabled
printk: bootconsole [uart8250] disabled
printk: bootconsole [uart8250] disabled
serial8250.0: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200 [+230400, 460800]) is a 16550A
serial8250.0: ttyS2 at MMIO 0x1f000900 (irq = 20, base_baud = 230400) is a 16550A
Otherwise there is no clear way to figure this out.
Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_core.c | 10 ++++++++++
drivers/tty/serial/serial_core.c | 11 +++++++++--
include/linux/serial_core.h | 3 +++
3 files changed, 22 insertions(+), 2 deletions(-)
linux-serial-core-baud-extra.diff
Index: linux-malta-cbus-uart/drivers/tty/serial/8250/8250_core.c
===================================================================
--- linux-malta-cbus-uart.orig/drivers/tty/serial/8250/8250_core.c
+++ linux-malta-cbus-uart/drivers/tty/serial/8250/8250_core.c
@@ -952,6 +952,13 @@ static struct uart_8250_port *serial8250
return NULL;
}
+static void serial8250_report_magic(struct uart_port *port,
+ char *report_buf, size_t report_size)
+{
+ snprintf(report_buf, report_size,
+ " [+%d, %d]", port->uartclk / 8, port->uartclk / 4);
+}
+
static void serial_8250_overrun_backoff_work(struct work_struct *work)
{
struct uart_8250_port *up =
@@ -1048,6 +1055,9 @@ int serial8250_register_8250_port(struct
}
}
+ if (up->port.flags & UPF_MAGIC_MULTIPLIER)
+ uart->port.report_extra = serial8250_report_magic;
+
serial8250_set_defaults(uart);
/* Possibly override default I/O functions. */
Index: linux-malta-cbus-uart/drivers/tty/serial/serial_core.c
===================================================================
--- linux-malta-cbus-uart.orig/drivers/tty/serial/serial_core.c
+++ linux-malta-cbus-uart/drivers/tty/serial/serial_core.c
@@ -2309,6 +2309,7 @@ int uart_resume_port(struct uart_driver
static inline void
uart_report_port(struct uart_driver *drv, struct uart_port *port)
{
+ char report_extra[64];
char address[64];
switch (port->iotype) {
@@ -2333,11 +2334,17 @@ uart_report_port(struct uart_driver *drv
break;
}
- pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
+ if (port->report_extra)
+ port->report_extra(port, report_extra, sizeof(report_extra));
+ else
+ report_extra[0] = '\0';
+
+ pr_info("%s%s%s at %s (irq = %d, base_baud = %d%s) is a %s\n",
port->dev ? dev_name(port->dev) : "",
port->dev ? ": " : "",
port->name,
- address, port->irq, port->uartclk / 16, uart_type(port));
+ address, port->irq, port->uartclk / 16, report_extra,
+ uart_type(port));
}
static void
Index: linux-malta-cbus-uart/include/linux/serial_core.h
===================================================================
--- linux-malta-cbus-uart.orig/include/linux/serial_core.h
+++ linux-malta-cbus-uart/include/linux/serial_core.h
@@ -135,6 +135,9 @@ struct uart_port {
struct serial_rs485 *rs485);
int (*iso7816_config)(struct uart_port *,
struct serial_iso7816 *iso7816);
+ void (*report_extra)(struct uart_port *port,
+ char *report_buf,
+ size_t report_size);
unsigned int irq; /* irq number */
unsigned long irqflags; /* irq flags */
unsigned int uartclk; /* base uart clock */
