diff mbox series

[net,v2,1/2] net: mdio: mdio-bcm-unimac: Delay before first poll

Message ID 20231213222744.2891184-2-justin.chen@broadcom.com (mailing list archive)
State Accepted
Commit 268531be211f18c55f7ff5a1641d32c0fd0571cd
Delegated to: Netdev Maintainers
Headers show
Series net: mdio: mdio-bcm-unimac: optimizations and clean up | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success SINGLE THREAD; Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present fail Series targets non-next tree, but doesn't contain any Fixes tags
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1115 this patch: 1115
netdev/cc_maintainers success CCed 10 of 10 maintainers
netdev/build_clang success Errors and warnings before: 1142 this patch: 1142
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: 1142 this patch: 1142
netdev/checkpatch warning CHECK: usleep_range is preferred over udelay; see Documentation/timers/timers-howto.rst WARNING: networking block comments don't use an empty /* line, use /* Comment...
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

Commit Message

Justin Chen Dec. 13, 2023, 10:27 p.m. UTC 
With a clock interval of 400 nsec and a 64 bit transactions (32 bit
preamble & 16 bit control & 16 bit data), it is reasonable to assume
the mdio transaction will take 25.6 usec. Add a 30 usec delay before
the first poll to reduce the chance of a 1000-2000 usec sleep.

Reduce the timeout from 1000ms to 100ms as it is unlikely for the bus
to take this long.

Signed-off-by: Justin Chen <justin.chen@broadcom.com>
Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
---
v2
	- Add comment to address absense of C45 support

 drivers/net/mdio/mdio-bcm-unimac.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Comments

Andrew Lunn Dec. 14, 2023, 11:46 a.m. UTC | #1 
On Wed, Dec 13, 2023 at 02:27:43PM -0800, Justin Chen wrote:
> With a clock interval of 400 nsec and a 64 bit transactions (32 bit
> preamble & 16 bit control & 16 bit data), it is reasonable to assume
> the mdio transaction will take 25.6 usec. Add a 30 usec delay before
> the first poll to reduce the chance of a 1000-2000 usec sleep.
> 
> Reduce the timeout from 1000ms to 100ms as it is unlikely for the bus
> to take this long.
> 
> Signed-off-by: Justin Chen <justin.chen@broadcom.com>
> Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew
diff mbox series

Patch

diff --git a/drivers/net/mdio/mdio-bcm-unimac.c b/drivers/net/mdio/mdio-bcm-unimac.c
index e8cd8eef319b..297ea4a58d79 100644
--- a/drivers/net/mdio/mdio-bcm-unimac.c
+++ b/drivers/net/mdio/mdio-bcm-unimac.c
@@ -81,7 +81,13 @@  static inline unsigned int unimac_mdio_busy(struct unimac_mdio_priv *priv)
 static int unimac_mdio_poll(void *wait_func_data)
 {
 	struct unimac_mdio_priv *priv = wait_func_data;
-	unsigned int timeout = 1000;
+	unsigned int timeout = 100;
+
+	/*
+	 * C22 transactions should take ~25 usec, will need to adjust
+	 * if C45 support is added.
+	 */
+	udelay(30);
 
 	do {
 		if (!unimac_mdio_busy(priv))