* [PATCH 1/2] spi/pl022: timeout on polled transfer
@ 2011-05-19 12:13 ` Linus Walleij
0 siblings, 0 replies; 8+ messages in thread
From: Linus Walleij @ 2011-05-19 12:13 UTC (permalink / raw)
To: Grant Likely, spi-devel-general
Cc: Linus Walleij, Lee Jones, linux-arm-kernel, Magnus Templing
From: Magnus Templing <magnus.templing@stericsson.com>
This adds the missing handling of polling timeouts and deletes
our last todo.
Signed-off-by: Magnus Templing <magnus.templing@stericsson.com>
Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/spi/amba-pl022.c | 22 ++++++++++++++--------
1 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/drivers/spi/amba-pl022.c b/drivers/spi/amba-pl022.c
index 08de58e..1f84a8a 100644
--- a/drivers/spi/amba-pl022.c
+++ b/drivers/spi/amba-pl022.c
@@ -24,11 +24,6 @@
* GNU General Public License for more details.
*/
-/*
- * TODO:
- * - add timeout on polled transfers
- */
-
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
@@ -287,6 +282,8 @@
#define CLEAR_ALL_INTERRUPTS 0x3
+#define SPI_POLLING_TIMEOUT 1000
+
/*
* The type of reading going on on this chip
@@ -1378,6 +1375,7 @@ static void do_polling_transfer(struct pl022 *pl022)
struct spi_transfer *transfer = NULL;
struct spi_transfer *previous = NULL;
struct chip_data *chip;
+ unsigned long timeout;
chip = pl022->cur_chip;
message = pl022->cur_msg;
@@ -1415,9 +1413,17 @@ static void do_polling_transfer(struct pl022 *pl022)
SSP_CR1(pl022->virtbase));
dev_dbg(&pl022->adev->dev, "polling transfer ongoing ...\n");
- /* FIXME: insert a timeout so we don't hang here indefinitely */
- while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end)
+
+ timeout = jiffies + msecs_to_jiffies(SPI_POLLING_TIMEOUT);
+ while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end) {
+ if (time_after(jiffies, timeout)) {
+ dev_warn(&pl022->adev->dev,
+ "%s: timeout!\n", __func__);
+ message->state = STATE_ERROR;
+ goto out;
+ }
readwriter(pl022);
+ }
/* Update total byte transferred */
message->actual_length += pl022->cur_transfer->len;
@@ -1426,7 +1432,7 @@ static void do_polling_transfer(struct pl022 *pl022)
/* Move to next transfer */
message->state = next_transfer(pl022);
}
-
+out:
/* Handle end of message */
if (message->state == STATE_DONE)
message->status = 0;
--
1.7.3.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 1/2] spi/pl022: timeout on polled transfer
@ 2011-05-19 12:13 ` Linus Walleij
0 siblings, 0 replies; 8+ messages in thread
From: Linus Walleij @ 2011-05-19 12:13 UTC (permalink / raw)
To: linux-arm-kernel
From: Magnus Templing <magnus.templing@stericsson.com>
This adds the missing handling of polling timeouts and deletes
our last todo.
Signed-off-by: Magnus Templing <magnus.templing@stericsson.com>
Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/spi/amba-pl022.c | 22 ++++++++++++++--------
1 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/drivers/spi/amba-pl022.c b/drivers/spi/amba-pl022.c
index 08de58e..1f84a8a 100644
--- a/drivers/spi/amba-pl022.c
+++ b/drivers/spi/amba-pl022.c
@@ -24,11 +24,6 @@
* GNU General Public License for more details.
*/
-/*
- * TODO:
- * - add timeout on polled transfers
- */
-
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
@@ -287,6 +282,8 @@
#define CLEAR_ALL_INTERRUPTS 0x3
+#define SPI_POLLING_TIMEOUT 1000
+
/*
* The type of reading going on on this chip
@@ -1378,6 +1375,7 @@ static void do_polling_transfer(struct pl022 *pl022)
struct spi_transfer *transfer = NULL;
struct spi_transfer *previous = NULL;
struct chip_data *chip;
+ unsigned long timeout;
chip = pl022->cur_chip;
message = pl022->cur_msg;
@@ -1415,9 +1413,17 @@ static void do_polling_transfer(struct pl022 *pl022)
SSP_CR1(pl022->virtbase));
dev_dbg(&pl022->adev->dev, "polling transfer ongoing ...\n");
- /* FIXME: insert a timeout so we don't hang here indefinitely */
- while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end)
+
+ timeout = jiffies + msecs_to_jiffies(SPI_POLLING_TIMEOUT);
+ while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end) {
+ if (time_after(jiffies, timeout)) {
+ dev_warn(&pl022->adev->dev,
+ "%s: timeout!\n", __func__);
+ message->state = STATE_ERROR;
+ goto out;
+ }
readwriter(pl022);
+ }
/* Update total byte transferred */
message->actual_length += pl022->cur_transfer->len;
@@ -1426,7 +1432,7 @@ static void do_polling_transfer(struct pl022 *pl022)
/* Move to next transfer */
message->state = next_transfer(pl022);
}
-
+out:
/* Handle end of message */
if (message->state == STATE_DONE)
message->status = 0;
--
1.7.3.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] spi/pl022: timeout on polled transfer
2011-05-19 12:13 ` Linus Walleij
@ 2011-05-19 12:44 ` Wolfram Sang
-1 siblings, 0 replies; 8+ messages in thread
From: Wolfram Sang @ 2011-05-19 12:44 UTC (permalink / raw)
To: Linus Walleij
Cc: Linus Walleij, Magnus Templing, Grant Likely, spi-devel-general,
Lee Jones, linux-arm-kernel
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Hi,
> - /* FIXME: insert a timeout so we don't hang here indefinitely */
> - while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end)
> +
> + timeout = jiffies + msecs_to_jiffies(SPI_POLLING_TIMEOUT);
Won't you miss the transfer if you get interrupted here longer than
SPI_POLLING_TIMEOUT?
> + while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end) {
> + if (time_after(jiffies, timeout)) {
> + dev_warn(&pl022->adev->dev,
> + "%s: timeout!\n", __func__);
> + message->state = STATE_ERROR;
> + goto out;
> + }
> readwriter(pl022);
> + }
Regards,
Wolfram
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 1/2] spi/pl022: timeout on polled transfer
@ 2011-05-19 12:44 ` Wolfram Sang
0 siblings, 0 replies; 8+ messages in thread
From: Wolfram Sang @ 2011-05-19 12:44 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
> - /* FIXME: insert a timeout so we don't hang here indefinitely */
> - while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end)
> +
> + timeout = jiffies + msecs_to_jiffies(SPI_POLLING_TIMEOUT);
Won't you miss the transfer if you get interrupted here longer than
SPI_POLLING_TIMEOUT?
> + while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end) {
> + if (time_after(jiffies, timeout)) {
> + dev_warn(&pl022->adev->dev,
> + "%s: timeout!\n", __func__);
> + message->state = STATE_ERROR;
> + goto out;
> + }
> readwriter(pl022);
> + }
Regards,
Wolfram
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] spi/pl022: timeout on polled transfer
2011-05-19 12:44 ` Wolfram Sang
@ 2011-05-19 13:23 ` Linus Walleij
-1 siblings, 0 replies; 8+ messages in thread
From: Linus Walleij @ 2011-05-19 13:23 UTC (permalink / raw)
To: Wolfram Sang
Cc: Linus Walleij, Magnus Templing, Grant Likely, spi-devel-general,
Lee Jones, linux-arm-kernel
On Thu, May 19, 2011 at 2:44 PM, Wolfram Sang <w.sang@pengutronix.de> wrote:
> Hi,
>
>> - /* FIXME: insert a timeout so we don't hang here indefinitely */
>> - while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end)
>> +
>> + timeout = jiffies + msecs_to_jiffies(SPI_POLLING_TIMEOUT);
>
> Won't you miss the transfer if you get interrupted here longer than
> SPI_POLLING_TIMEOUT?
Yeah... preempted for a second hm.
>> + while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end) {
>> + if (time_after(jiffies, timeout)) {
>> + dev_warn(&pl022->adev->dev,
>> + "%s: timeout!\n", __func__);
>> + message->state = STATE_ERROR;
>> + goto out;
>> + }
>> readwriter(pl022);
>> + }
What about we move readerwriter() above if (time_after...) then it atleast
gets one chance to run even if we're preempted for 10 seconds.
Any other design patterns that'd be better?
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 1/2] spi/pl022: timeout on polled transfer
@ 2011-05-19 13:23 ` Linus Walleij
0 siblings, 0 replies; 8+ messages in thread
From: Linus Walleij @ 2011-05-19 13:23 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, May 19, 2011 at 2:44 PM, Wolfram Sang <w.sang@pengutronix.de> wrote:
> Hi,
>
>> - ? ? ? ? ? ? /* FIXME: insert a timeout so we don't hang here indefinitely */
>> - ? ? ? ? ? ? while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end)
>> +
>> + ? ? ? ? ? ? timeout = jiffies + msecs_to_jiffies(SPI_POLLING_TIMEOUT);
>
> Won't you miss the transfer if you get interrupted here longer than
> SPI_POLLING_TIMEOUT?
Yeah... preempted for a second hm.
>> + ? ? ? ? ? ? while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end) {
>> + ? ? ? ? ? ? ? ? ? ? if (time_after(jiffies, timeout)) {
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? dev_warn(&pl022->adev->dev,
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? "%s: timeout!\n", __func__);
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? message->state = STATE_ERROR;
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? goto out;
>> + ? ? ? ? ? ? ? ? ? ? }
>> ? ? ? ? ? ? ? ? ? ? ? readwriter(pl022);
>> + ? ? ? ? ? ? }
What about we move readerwriter() above if (time_after...) then it atleast
gets one chance to run even if we're preempted for 10 seconds.
Any other design patterns that'd be better?
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] spi/pl022: timeout on polled transfer
2011-05-19 13:23 ` Linus Walleij
@ 2011-05-19 14:23 ` Wolfram Sang
-1 siblings, 0 replies; 8+ messages in thread
From: Wolfram Sang @ 2011-05-19 14:23 UTC (permalink / raw)
To: Linus Walleij
Cc: Linus Walleij, Magnus Templing, Grant Likely, spi-devel-general,
Lee Jones, linux-arm-kernel
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> >> + while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end) {
> >> + if (time_after(jiffies, timeout)) {
> >> + dev_warn(&pl022->adev->dev,
> >> + "%s: timeout!\n", __func__);
> >> + message->state = STATE_ERROR;
> >> + goto out;
> >> + }
> >> readwriter(pl022);
> >> + }
>
> What about we move readerwriter() above if (time_after...) then it atleast
> gets one chance to run even if we're preempted for 10 seconds.
This will fix the initial problem, but still exit early if e.g. the
preemption came on a subsequent iteration of the while loop, say during
readwriter().
>
> Any other design patterns that'd be better?
A bit better might be:
while (...) {
time = jiffies;
readwriter();
if (time_after(time, timeout)...)
...
}
So you continue triggering transfers as long as the last one was in the
valid timespan. In case of an preemption, you made sure you tried the
whole timespan (+ the jitter) which is probably better than stop trying
too early.
Regards,
Wolfram
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 1/2] spi/pl022: timeout on polled transfer
@ 2011-05-19 14:23 ` Wolfram Sang
0 siblings, 0 replies; 8+ messages in thread
From: Wolfram Sang @ 2011-05-19 14:23 UTC (permalink / raw)
To: linux-arm-kernel
> >> + ? ? ? ? ? ? while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end) {
> >> + ? ? ? ? ? ? ? ? ? ? if (time_after(jiffies, timeout)) {
> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? dev_warn(&pl022->adev->dev,
> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? "%s: timeout!\n", __func__);
> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? message->state = STATE_ERROR;
> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? goto out;
> >> + ? ? ? ? ? ? ? ? ? ? }
> >> ? ? ? ? ? ? ? ? ? ? ? readwriter(pl022);
> >> + ? ? ? ? ? ? }
>
> What about we move readerwriter() above if (time_after...) then it atleast
> gets one chance to run even if we're preempted for 10 seconds.
This will fix the initial problem, but still exit early if e.g. the
preemption came on a subsequent iteration of the while loop, say during
readwriter().
>
> Any other design patterns that'd be better?
A bit better might be:
while (...) {
time = jiffies;
readwriter();
if (time_after(time, timeout)...)
...
}
So you continue triggering transfers as long as the last one was in the
valid timespan. In case of an preemption, you made sure you tried the
whole timespan (+ the jitter) which is probably better than stop trying
too early.
Regards,
Wolfram
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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end of thread, other threads:[~2011-05-19 14:23 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
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2011-05-19 12:13 [PATCH 1/2] spi/pl022: timeout on polled transfer Linus Walleij
2011-05-19 12:13 ` Linus Walleij
2011-05-19 12:44 ` Wolfram Sang
2011-05-19 12:44 ` Wolfram Sang
2011-05-19 13:23 ` Linus Walleij
2011-05-19 13:23 ` Linus Walleij
2011-05-19 14:23 ` Wolfram Sang
2011-05-19 14:23 ` Wolfram Sang
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