* [PATCH] tty: serial: uartlite: Use read_poll_timeout for a polling loop
@ 2021-07-23 21:52 Sean Anderson
2021-07-23 21:55 ` Sean Anderson
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Sean Anderson @ 2021-07-23 21:52 UTC (permalink / raw)
To: linux-serial, Peter Korsgaard
Cc: Michal Simek, Greg Kroah-Hartman, Sean Anderson
This uses read_poll_timeout_atomic to spin while waiting on uart_in32.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
---
drivers/tty/serial/uartlite.c | 18 +++++-------------
1 file changed, 5 insertions(+), 13 deletions(-)
diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index f42ccc40ffa6..106bbbc86c87 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c
@@ -17,6 +17,7 @@
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
@@ -448,24 +449,15 @@ static const struct uart_ops ulite_ops = {
static void ulite_console_wait_tx(struct uart_port *port)
{
u8 val;
- unsigned long timeout;
/*
* Spin waiting for TX fifo to have space available.
* When using the Microblaze Debug Module this can take up to 1s
*/
- timeout = jiffies + msecs_to_jiffies(1000);
- while (1) {
- val = uart_in32(ULITE_STATUS, port);
- if ((val & ULITE_STATUS_TXFULL) == 0)
- break;
- if (time_after(jiffies, timeout)) {
- dev_warn(port->dev,
- "timeout waiting for TX buffer empty\n");
- break;
- }
- cpu_relax();
- }
+ if (read_poll_timeout_atomic(uart_in32, val, !(val & ULITE_STATUS_TXFULL),
+ 0, 1000000, false, ULITE_STATUS, port))
+ dev_warn(port->dev,
+ "timeout waiting for TX buffer empty\n");
}
static void ulite_console_putchar(struct uart_port *port, int ch)
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] tty: serial: uartlite: Use read_poll_timeout for a polling loop
2021-07-23 21:52 [PATCH] tty: serial: uartlite: Use read_poll_timeout for a polling loop Sean Anderson
@ 2021-07-23 21:55 ` Sean Anderson
2021-07-26 14:19 ` Michal Simek
2021-07-29 14:59 ` Greg Kroah-Hartman
2 siblings, 0 replies; 5+ messages in thread
From: Sean Anderson @ 2021-07-23 21:55 UTC (permalink / raw)
To: linux-serial, Peter Korsgaard
Cc: Michal Simek, Greg Kroah-Hartman, Peter Korsgaard,
Peter Korsgaard
Looks like Peter's email bounces.
+CC the other emails of "Peter Korsgaard" in MAINTAINERS
On 7/23/21 5:52 PM, Sean Anderson wrote:
> This uses read_poll_timeout_atomic to spin while waiting on uart_in32.
>
> Signed-off-by: Sean Anderson <sean.anderson@seco.com>
> ---
>
> drivers/tty/serial/uartlite.c | 18 +++++-------------
> 1 file changed, 5 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
> index f42ccc40ffa6..106bbbc86c87 100644
> --- a/drivers/tty/serial/uartlite.c
> +++ b/drivers/tty/serial/uartlite.c
> @@ -17,6 +17,7 @@
> #include <linux/interrupt.h>
> #include <linux/init.h>
> #include <linux/io.h>
> +#include <linux/iopoll.h>
> #include <linux/of.h>
> #include <linux/of_address.h>
> #include <linux/of_device.h>
> @@ -448,24 +449,15 @@ static const struct uart_ops ulite_ops = {
> static void ulite_console_wait_tx(struct uart_port *port)
> {
> u8 val;
> - unsigned long timeout;
>
> /*
> * Spin waiting for TX fifo to have space available.
> * When using the Microblaze Debug Module this can take up to 1s
> */
> - timeout = jiffies + msecs_to_jiffies(1000);
> - while (1) {
> - val = uart_in32(ULITE_STATUS, port);
> - if ((val & ULITE_STATUS_TXFULL) == 0)
> - break;
> - if (time_after(jiffies, timeout)) {
> - dev_warn(port->dev,
> - "timeout waiting for TX buffer empty\n");
> - break;
> - }
> - cpu_relax();
> - }
> + if (read_poll_timeout_atomic(uart_in32, val, !(val & ULITE_STATUS_TXFULL),
> + 0, 1000000, false, ULITE_STATUS, port))
> + dev_warn(port->dev,
> + "timeout waiting for TX buffer empty\n");
> }
>
> static void ulite_console_putchar(struct uart_port *port, int ch)
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] tty: serial: uartlite: Use read_poll_timeout for a polling loop
2021-07-23 21:52 [PATCH] tty: serial: uartlite: Use read_poll_timeout for a polling loop Sean Anderson
2021-07-23 21:55 ` Sean Anderson
@ 2021-07-26 14:19 ` Michal Simek
2021-07-29 14:59 ` Greg Kroah-Hartman
2 siblings, 0 replies; 5+ messages in thread
From: Michal Simek @ 2021-07-26 14:19 UTC (permalink / raw)
To: Sean Anderson, linux-serial, Peter Korsgaard, Shubhrajyoti Datta
Cc: Michal Simek, Greg Kroah-Hartman
+Shubhrajyoti
On 7/23/21 11:52 PM, Sean Anderson wrote:
> This uses read_poll_timeout_atomic to spin while waiting on uart_in32.
>
> Signed-off-by: Sean Anderson <sean.anderson@seco.com>
> ---
>
> drivers/tty/serial/uartlite.c | 18 +++++-------------
> 1 file changed, 5 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
> index f42ccc40ffa6..106bbbc86c87 100644
> --- a/drivers/tty/serial/uartlite.c
> +++ b/drivers/tty/serial/uartlite.c
> @@ -17,6 +17,7 @@
> #include <linux/interrupt.h>
> #include <linux/init.h>
> #include <linux/io.h>
> +#include <linux/iopoll.h>
> #include <linux/of.h>
> #include <linux/of_address.h>
> #include <linux/of_device.h>
> @@ -448,24 +449,15 @@ static const struct uart_ops ulite_ops = {
> static void ulite_console_wait_tx(struct uart_port *port)
> {
> u8 val;
> - unsigned long timeout;
>
> /*
> * Spin waiting for TX fifo to have space available.
> * When using the Microblaze Debug Module this can take up to 1s
> */
> - timeout = jiffies + msecs_to_jiffies(1000);
> - while (1) {
> - val = uart_in32(ULITE_STATUS, port);
> - if ((val & ULITE_STATUS_TXFULL) == 0)
> - break;
> - if (time_after(jiffies, timeout)) {
> - dev_warn(port->dev,
> - "timeout waiting for TX buffer empty\n");
> - break;
> - }
> - cpu_relax();
> - }
> + if (read_poll_timeout_atomic(uart_in32, val, !(val & ULITE_STATUS_TXFULL),
> + 0, 1000000, false, ULITE_STATUS, port))
> + dev_warn(port->dev,
> + "timeout waiting for TX buffer empty\n");
> }
>
> static void ulite_console_putchar(struct uart_port *port, int ch)
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] tty: serial: uartlite: Use read_poll_timeout for a polling loop
2021-07-23 21:52 [PATCH] tty: serial: uartlite: Use read_poll_timeout for a polling loop Sean Anderson
2021-07-23 21:55 ` Sean Anderson
2021-07-26 14:19 ` Michal Simek
@ 2021-07-29 14:59 ` Greg Kroah-Hartman
2021-07-29 15:31 ` Sean Anderson
2 siblings, 1 reply; 5+ messages in thread
From: Greg Kroah-Hartman @ 2021-07-29 14:59 UTC (permalink / raw)
To: Sean Anderson; +Cc: linux-serial, Peter Korsgaard, Michal Simek
On Fri, Jul 23, 2021 at 05:52:20PM -0400, Sean Anderson wrote:
> This uses read_poll_timeout_atomic to spin while waiting on uart_in32.
That says what you are doing, but nothing about _why_ you are making
this change. Please fix up.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] tty: serial: uartlite: Use read_poll_timeout for a polling loop
2021-07-29 14:59 ` Greg Kroah-Hartman
@ 2021-07-29 15:31 ` Sean Anderson
0 siblings, 0 replies; 5+ messages in thread
From: Sean Anderson @ 2021-07-29 15:31 UTC (permalink / raw)
To: Greg Kroah-Hartman; +Cc: linux-serial, Peter Korsgaard, Michal Simek
On 7/29/21 10:59 AM, Greg Kroah-Hartman wrote:
> On Fri, Jul 23, 2021 at 05:52:20PM -0400, Sean Anderson wrote:
>> This uses read_poll_timeout_atomic to spin while waiting on uart_in32.
>
> That says what you are doing, but nothing about _why_ you are making
> this change. Please fix up.
Ok, how about
read_poll_timeout was recently introduced, and can be used to simplify
our console polling loop. This results in a slight reduction in code.
early_uartlite_putc can't get the same treatment, because it can be
called before udelay is set up.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-07-23 21:52 [PATCH] tty: serial: uartlite: Use read_poll_timeout for a polling loop Sean Anderson
2021-07-23 21:55 ` Sean Anderson
2021-07-26 14:19 ` Michal Simek
2021-07-29 14:59 ` Greg Kroah-Hartman
2021-07-29 15:31 ` Sean Anderson
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