[PATCH] raw/cnxk_gpio: allow controlling existing GPIO

[PATCH] raw/cnxk_gpio: allow controlling existing GPIO

[Tomasz Duszynski]

Controlling existing GPIO should be normally frowned upon because
we want to avoid situation where multiple contenders modify GPIO
state simultaneously.

Still there might be situations where this is actually needed.
Restarting killed application being an example here.

So relax current restrictions and respect user needs.

Signed-off-by: Tomasz Duszynski <tduszynski@marvell.com>
---
 drivers/raw/cnxk_gpio/cnxk_gpio.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/drivers/raw/cnxk_gpio/cnxk_gpio.c b/drivers/raw/cnxk_gpio/cnxk_gpio.c
index 9577753851..d759ed82d4 100644
--- a/drivers/raw/cnxk_gpio/cnxk_gpio.c
+++ b/drivers/raw/cnxk_gpio/cnxk_gpio.c
@@ -4,6 +4,7 @@
 
 #include <dirent.h>
 #include <string.h>
+#include <sys/stat.h>
 
 #include <rte_bus_vdev.h>
 #include <rte_eal.h>
@@ -277,6 +278,17 @@ cnxk_gpio_lookup(struct cnxk_gpiochip *gpiochip, uint16_t queue)
 	return gpiochip->gpios[gpio];
 }
 
+static bool
+cnxk_gpio_exists(int num)
+{
+	char buf[CNXK_GPIO_BUFSZ];
+	struct stat st;
+
+	snprintf(buf, sizeof(buf), "%s/gpio%d", CNXK_GPIO_CLASS_PATH, num);
+
+	return !stat(buf, &st);
+}
+
 static int
 cnxk_gpio_queue_setup(struct rte_rawdev *dev, uint16_t queue_id,
 		      rte_rawdev_obj_t queue_conf, size_t queue_conf_size)
@@ -304,11 +316,15 @@ cnxk_gpio_queue_setup(struct rte_rawdev *dev, uint16_t queue_id,
 	gpio->num = num + gpiochip->base;
 	gpio->gpiochip = gpiochip;
 
-	snprintf(buf, sizeof(buf), "%s/export", CNXK_GPIO_CLASS_PATH);
-	ret = cnxk_gpio_write_attr_int(buf, gpio->num);
-	if (ret) {
-		rte_free(gpio);
-		return ret;
+	if (!cnxk_gpio_exists(gpio->num)) {
+		snprintf(buf, sizeof(buf), "%s/export", CNXK_GPIO_CLASS_PATH);
+		ret = cnxk_gpio_write_attr_int(buf, gpio->num);
+		if (ret) {
+			rte_free(gpio);
+			return ret;
+		}
+	} else {
+		RTE_LOG(WARNING, PMD, "using existing gpio%d\n", gpio->num);
 	}
 
 	gpiochip->gpios[num] = gpio;
-- 
2.25.1

Re: [PATCH] raw/cnxk_gpio: allow controlling existing GPIO

[Thomas Monjalon]

04/06/2022 16:03, Tomasz Duszynski:
> Controlling existing GPIO should be normally frowned upon because
> we want to avoid situation where multiple contenders modify GPIO
> state simultaneously.
> 
> Still there might be situations where this is actually needed.
> Restarting killed application being an example here.
> 
> So relax current restrictions and respect user needs.
> 
> Signed-off-by: Tomasz Duszynski <tduszynski@marvell.com>

Applied, thanks.