diff mbox series

[net-next,v8,01/16] net: dsa: vsc73xx: use read_poll_timeout instead delay loop

Message ID 20240403103734.3033398-2-paweldembicki@gmail.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series net: dsa: vsc73xx: Make vsc73xx usable | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches (and no cover letter)
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 943 this patch: 943
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 954 this patch: 954
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 954 this patch: 954
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 54 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-04-05--03-00 (tests: 951)

Commit Message

Pawel Dembicki April 3, 2024, 10:37 a.m. UTC 
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@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
---
v8,v7,v6:
  - resend only
v5:
  - improved commit description
  - added two defines instead magic numbers
  - added include with iopoll.h
v4:
  - resend patch
v3:
  - added "Reviewed-by" to commit message only
v2:
  - introduced patch

 drivers/net/dsa/vitesse-vsc73xx-core.c | 30 ++++++++++++++------------
 1 file changed, 16 insertions(+), 14 deletions(-)

Comments

Vladimir Oltean April 5, 2024, 2:32 p.m. UTC | #1 
On Wed, Apr 03, 2024 at 12:37:17PM +0200, Pawel Dembicki wrote:
> 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@armlinux.org.uk>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
> Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
> ---

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
diff mbox series

Patch

diff --git a/drivers/net/dsa/vitesse-vsc73xx-core.c b/drivers/net/dsa/vitesse-vsc73xx-core.c
index ae70eac3be28..ab5771d4d828 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_mdio.h>
 #include <linux/bitops.h>
@@ -268,6 +269,9 @@ 
 #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;
@@ -779,7 +783,7 @@  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);
@@ -794,19 +798,17 @@  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,