diff mbox series

[net-next,2/7] net: sfp: check firmware provided max power

Message ID E1olteZ-00Fwwo-UC@rmk-PC.armlinux.org.uk (mailing list archive)
State Accepted
Commit 02eaf5a79100468425fae2d0baf144b6068fc4cc
Delegated to: Netdev Maintainers
Headers show
Series net: sfp: improve high power module implementation | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
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: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 37 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Russell King (Oracle) Oct. 21, 2022, 3:09 p.m. UTC
Check that the firmware provided maximum power is at least 1W, which
iis the minimum power level for any SFP module.

Now that we enforce the minimum of 1W, we can exit early from
sfp_module_parse_power() if the module power is 1W or less.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/phy/sfp.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index 40c9a64c5e30..f7ad4d5d9041 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -1766,6 +1766,12 @@  static int sfp_module_parse_power(struct sfp *sfp)
 	if (sfp->id.ext.options & cpu_to_be16(SFP_OPTIONS_HIGH_POWER_LEVEL))
 		power_mW = 2000;
 
+	/* Power level 1 modules (max. 1W) are always supported. */
+	if (power_mW <= 1000) {
+		sfp->module_power_mW = power_mW;
+		return 0;
+	}
+
 	supports_a2 = sfp->id.ext.sff8472_compliance !=
 				SFP_SFF8472_COMPLIANCE_NONE ||
 		      sfp->id.ext.diagmon & SFP_DIAGMON_DDM;
@@ -1789,12 +1795,6 @@  static int sfp_module_parse_power(struct sfp *sfp)
 		}
 	}
 
-	if (power_mW <= 1000) {
-		/* Modules below 1W do not require a power change sequence */
-		sfp->module_power_mW = power_mW;
-		return 0;
-	}
-
 	if (!supports_a2) {
 		/* The module power level is below the host maximum and the
 		 * module appears not to implement bus address 0xa2, so assume
@@ -2729,8 +2729,12 @@  static int sfp_probe(struct platform_device *pdev)
 
 	device_property_read_u32(&pdev->dev, "maximum-power-milliwatt",
 				 &sfp->max_power_mW);
-	if (!sfp->max_power_mW)
+	if (sfp->max_power_mW < 1000) {
+		if (sfp->max_power_mW)
+			dev_warn(sfp->dev,
+				 "Firmware bug: host maximum power should be at least 1W\n");
 		sfp->max_power_mW = 1000;
+	}
 
 	dev_info(sfp->dev, "Host maximum power %u.%uW\n",
 		 sfp->max_power_mW / 1000, (sfp->max_power_mW / 100) % 10);