* [PATCHv2] serial: don't register CIR serial ports
@ 2015-08-05 15:43 Maciej S. Szmigiero
2015-08-05 19:02 ` Peter Hurley
0 siblings, 1 reply; 2+ messages in thread
From: Maciej S. Szmigiero @ 2015-08-05 15:43 UTC (permalink / raw)
To: linux-serial; +Cc: Greg Kroah-Hartman, Jiri Slaby, linux-kernel, Peter Hurley
CIR type serial ports aren't real serial ports.
This is just a way to prevent legacy 8250 serial
driver from probing and eventually binding some
resources.
Since in current state such ports aren't providing
any real functionality and it is not possible
to change their type via setserial/ioctl(TIOCSSERIAL)
(due to UPF_FIXED_PORT flag set on them)
it is simpler and cleaner to not register them at all
with serial core.
Print a short message in this case so it is known
to user what has happened.
This way checks for PORT_8250_CIR in serial port
callbacks can be removed too, since they won't
ever be called.
Signed-off-by: Maciej Szmigiero <mail@maciej.szmigiero.name>
---
This replaces "serial: don't announce CIR serial ports"
submission.
Changes from v1: print message using dev_info()
drivers/tty/serial/8250/8250_core.c | 37 +++++++++++++++++------------------
1 files changed, 18 insertions(+), 19 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 37fff12..145b0b37 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2129,9 +2129,6 @@ int serial8250_do_startup(struct uart_port *port)
unsigned char lsr, iir;
int retval;
- if (port->type == PORT_8250_CIR)
- return -ENODEV;
-
if (!port->fifosize)
port->fifosize = uart_config[port->type].fifo_size;
if (!up->tx_loadsz)
@@ -2858,14 +2855,8 @@ static void serial8250_release_port(struct uart_port *port)
static int serial8250_request_port(struct uart_port *port)
{
struct uart_8250_port *up = up_to_u8250p(port);
- int ret;
-
- if (port->type == PORT_8250_CIR)
- return -ENODEV;
-
- ret = serial8250_request_std_resource(up);
- return ret;
+ return serial8250_request_std_resource(up);
}
static int fcr_get_rxtrig_bytes(struct uart_8250_port *up)
@@ -3013,9 +3004,6 @@ static void serial8250_config_port(struct uart_port *port, int flags)
struct uart_8250_port *up = up_to_u8250p(port);
int ret;
- if (port->type == PORT_8250_CIR)
- return;
-
/*
* Find the region that we can probe for. This in turn
* tells us whether we can probe for the type of port.
@@ -3889,13 +3877,24 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
if (up->dl_write)
uart->dl_write = up->dl_write;
- if (serial8250_isa_config != NULL)
- serial8250_isa_config(0, &uart->port,
- &uart->capabilities);
+ if (uart->port.type != PORT_8250_CIR) {
+ if (serial8250_isa_config != NULL)
+ serial8250_isa_config(0, &uart->port,
+ &uart->capabilities);
- ret = uart_add_one_port(&serial8250_reg, &uart->port);
- if (ret == 0)
- ret = uart->port.line;
+ ret = uart_add_one_port(&serial8250_reg,
+ &uart->port);
+ if (ret == 0)
+ ret = uart->port.line;
+ } else {
+ dev_info(uart->port.dev,
+ "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
+ uart->port.iobase,
+ (unsigned long long)uart->port.mapbase,
+ uart->port.irq);
+
+ ret = 0;
+ }
}
mutex_unlock(&serial_mutex);
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCHv2] serial: don't register CIR serial ports
2015-08-05 15:43 [PATCHv2] serial: don't register CIR serial ports Maciej S. Szmigiero
@ 2015-08-05 19:02 ` Peter Hurley
0 siblings, 0 replies; 2+ messages in thread
From: Peter Hurley @ 2015-08-05 19:02 UTC (permalink / raw)
To: Maciej S. Szmigiero, linux-serial
Cc: Greg Kroah-Hartman, Jiri Slaby, linux-kernel
On 08/05/2015 11:43 AM, Maciej S. Szmigiero wrote:
> CIR type serial ports aren't real serial ports.
>
> This is just a way to prevent legacy 8250 serial
> driver from probing and eventually binding some
> resources.
>
> Since in current state such ports aren't providing
> any real functionality and it is not possible
> to change their type via setserial/ioctl(TIOCSSERIAL)
> (due to UPF_FIXED_PORT flag set on them)
> it is simpler and cleaner to not register them at all
> with serial core.
The only thing I think this patch is missing is either a comment
or specific code in serial8250_register_ports() regarding not
adding PORT_8250_CIR-type ports.
Like either:
static void __init
serial8250_register_ports(struct uart_driver *drv, struct device *dev)
{
int i;
for (i = 0; i < nr_uarts; i++) {
struct uart_8250_port *up = &serial8250_ports[i];
+ /* PORT_8250_CIR-type ports must have non-NULL dev */
if (up->port.dev)
continue;
up->port.dev = dev;
or:
static void __init
serial8250_register_ports(struct uart_driver *drv, struct device *dev)
{
int i;
for (i = 0; i < nr_uarts; i++) {
struct uart_8250_port *up = &serial8250_ports[i];
+ if (up->port.type == PORT_8250_CIR)
+ continue;
if (up->port.dev)
continue;
up->port.dev = dev;
Regards,
Peter Hurley
> Print a short message in this case so it is known
> to user what has happened.
>
> This way checks for PORT_8250_CIR in serial port
> callbacks can be removed too, since they won't
> ever be called.
>
> Signed-off-by: Maciej Szmigiero <mail@maciej.szmigiero.name>
> ---
> This replaces "serial: don't announce CIR serial ports"
> submission.
>
> Changes from v1: print message using dev_info()
>
> drivers/tty/serial/8250/8250_core.c | 37 +++++++++++++++++------------------
> 1 files changed, 18 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> index 37fff12..145b0b37 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -2129,9 +2129,6 @@ int serial8250_do_startup(struct uart_port *port)
> unsigned char lsr, iir;
> int retval;
>
> - if (port->type == PORT_8250_CIR)
> - return -ENODEV;
> -
> if (!port->fifosize)
> port->fifosize = uart_config[port->type].fifo_size;
> if (!up->tx_loadsz)
> @@ -2858,14 +2855,8 @@ static void serial8250_release_port(struct uart_port *port)
> static int serial8250_request_port(struct uart_port *port)
> {
> struct uart_8250_port *up = up_to_u8250p(port);
> - int ret;
> -
> - if (port->type == PORT_8250_CIR)
> - return -ENODEV;
> -
> - ret = serial8250_request_std_resource(up);
>
> - return ret;
> + return serial8250_request_std_resource(up);
> }
>
> static int fcr_get_rxtrig_bytes(struct uart_8250_port *up)
> @@ -3013,9 +3004,6 @@ static void serial8250_config_port(struct uart_port *port, int flags)
> struct uart_8250_port *up = up_to_u8250p(port);
> int ret;
>
> - if (port->type == PORT_8250_CIR)
> - return;
> -
> /*
> * Find the region that we can probe for. This in turn
> * tells us whether we can probe for the type of port.
> @@ -3889,13 +3877,24 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
> if (up->dl_write)
> uart->dl_write = up->dl_write;
>
> - if (serial8250_isa_config != NULL)
> - serial8250_isa_config(0, &uart->port,
> - &uart->capabilities);
> + if (uart->port.type != PORT_8250_CIR) {
> + if (serial8250_isa_config != NULL)
> + serial8250_isa_config(0, &uart->port,
> + &uart->capabilities);
>
> - ret = uart_add_one_port(&serial8250_reg, &uart->port);
> - if (ret == 0)
> - ret = uart->port.line;
> + ret = uart_add_one_port(&serial8250_reg,
> + &uart->port);
> + if (ret == 0)
> + ret = uart->port.line;
> + } else {
> + dev_info(uart->port.dev,
> + "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
> + uart->port.iobase,
> + (unsigned long long)uart->port.mapbase,
> + uart->port.irq);
> +
> + ret = 0;
> + }
> }
> mutex_unlock(&serial_mutex);
>
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2015-08-05 19:02 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-08-05 15:43 [PATCHv2] serial: don't register CIR serial ports Maciej S. Szmigiero
2015-08-05 19:02 ` Peter Hurley
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.