This is a note to let you know that I've just added the patch titled
net: dsa: vsc73xx: use read_poll_timeout instead delay loop
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-dsa-vsc73xx-use-read_poll_timeout-instead-delay-.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ce41bc649bca494b5095f52ec21aa92bfd111f65
Author: Pawel Dembicki <paweldembicki@xxxxxxxxx>
Date: Wed Apr 17 22:50:44 2024 +0200
net: dsa: vsc73xx: use read_poll_timeout instead delay loop
[ Upstream commit eb7e33d01db3aec128590391b2397384bab406b6 ]
Switch the delay loop during the Arbiter empty check from
vsc73xx_adjust_link() to use read_poll_timeout(). Functionally,
one msleep() call is eliminated at the end of the loop in the timeout
case.
As Russell King suggested:
"This [change] avoids the issue that on the last iteration, the code reads
the register, tests it, finds the condition that's being waiting for is
false, _then_ waits and end up printing the error message - that last
wait is rather useless, and as the arbiter state isn't checked after
waiting, it could be that we had success during the last wait."
Suggested-by: Russell King <linux@xxxxxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
Signed-off-by: Pawel Dembicki <paweldembicki@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240417205048.3542839-2-paweldembicki@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Stable-dep-of: fa63c6434b6f ("net: dsa: vsc73xx: check busy flag in MDIO operations")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/dsa/vitesse-vsc73xx-core.c b/drivers/net/dsa/vitesse-vsc73xx-core.c
index 15afb84155472..ce1c6d6eeb606 100644
--- a/drivers/net/dsa/vitesse-vsc73xx-core.c
+++ b/drivers/net/dsa/vitesse-vsc73xx-core.c
@@ -17,6 +17,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
+#include <linux/iopoll.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_mdio.h>
@@ -269,6 +270,9 @@
#define IS_7398(a) ((a)->chipid == VSC73XX_CHIPID_ID_7398)
#define IS_739X(a) (IS_7395(a) || IS_7398(a))
+#define VSC73XX_POLL_SLEEP_US 1000
+#define VSC73XX_POLL_TIMEOUT_US 10000
+
struct vsc73xx_counter {
u8 counter;
const char *name;
@@ -780,7 +784,7 @@ static void vsc73xx_adjust_link(struct dsa_switch *ds, int port,
* after a PHY or the CPU port comes up or down.
*/
if (!phydev->link) {
- int maxloop = 10;
+ int ret, err;
dev_dbg(vsc->dev, "port %d: went down\n",
port);
@@ -795,19 +799,17 @@ static void vsc73xx_adjust_link(struct dsa_switch *ds, int port,
VSC73XX_ARBDISC, BIT(port), BIT(port));
/* Wait until queue is empty */
- vsc73xx_read(vsc, VSC73XX_BLOCK_ARBITER, 0,
- VSC73XX_ARBEMPTY, &val);
- while (!(val & BIT(port))) {
- msleep(1);
- vsc73xx_read(vsc, VSC73XX_BLOCK_ARBITER, 0,
- VSC73XX_ARBEMPTY, &val);
- if (--maxloop == 0) {
- dev_err(vsc->dev,
- "timeout waiting for block arbiter\n");
- /* Continue anyway */
- break;
- }
- }
+ ret = read_poll_timeout(vsc73xx_read, err,
+ err < 0 || (val & BIT(port)),
+ VSC73XX_POLL_SLEEP_US,
+ VSC73XX_POLL_TIMEOUT_US, false,
+ vsc, VSC73XX_BLOCK_ARBITER, 0,
+ VSC73XX_ARBEMPTY, &val);
+ if (ret)
+ dev_err(vsc->dev,
+ "timeout waiting for block arbiter\n");
+ else if (err < 0)
+ dev_err(vsc->dev, "error reading arbiter\n");
/* Put this port into reset */
vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_MAC_CFG,
