[stable,4.14] net: phy: broadcom: stub c45 read/write for 54810

Commit Message

Florian Fainelli Aug. 21, 2023, 9:54 p.m. UTC

From: Justin Chen <[e-mail]>

commit 096516d092d54604d590827d05b1022c8f326639 upstream

The 54810 does not support c45. The mmd_phy_indirect accesses return
arbirtary values leading to odd behavior like saying it supports EEE
when it doesn't. We also see that reading/writing these non-existent
MMD registers leads to phy instability in some cases.

Fixes: b14995ac2527 ("net: phy: broadcom: Add BCM54810 PHY entry")
Signed-off-by: Justin Chen <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>
[florian: resolved conflicts in 4.14]
Signed-off-by: Florian Fainelli <[e-mail]>
---
 drivers/net/phy/broadcom.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

Comments

Greg Kroah-Hartman Aug. 22, 2023, 7:10 a.m. UTC | #1

On Mon, Aug 21, 2023 at 02:54:10PM -0700, Florian Fainelli wrote:
> From: Justin Chen <[e-mail]>
> 
> commit 096516d092d54604d590827d05b1022c8f326639 upstream
> 
> The 54810 does not support c45. The mmd_phy_indirect accesses return
> arbirtary values leading to odd behavior like saying it supports EEE
> when it doesn't. We also see that reading/writing these non-existent
> MMD registers leads to phy instability in some cases.
> 
> Fixes: b14995ac2527 ("net: phy: broadcom: Add BCM54810 PHY entry")
> Signed-off-by: Justin Chen <[e-mail]>
> Reviewed-by: Florian Fainelli <[e-mail]>
> Link: https://lore.kernel.org/r/[e-mail]
> Signed-off-by: Jakub Kicinski <[e-mail]>
> [florian: resolved conflicts in 4.14]
> Signed-off-by: Florian Fainelli <[e-mail]>

Thanks for these, all now queued up.

greg k-h

Patch

diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
index 97e017a54eb5..2fbb1277b3a8 100644
--- a/drivers/net/phy/broadcom.c
+++ b/drivers/net/phy/broadcom.c
@@ -403,6 +403,17 @@  static int bcm5482_read_status(struct phy_device *phydev)
 	return err;
 }
 
+static int bcm54810_read_mmd(struct phy_device *phydev, int devnum, u16 regnum)
+{
+	return -EOPNOTSUPP;
+}
+
+static int bcm54810_write_mmd(struct phy_device *phydev, int devnum, u16 regnum,
+			      u16 val)
+{
+	return -EOPNOTSUPP;
+}
+
 static int bcm5481_config_aneg(struct phy_device *phydev)
 {
 	struct device_node *np = phydev->mdio.dev.of_node;
@@ -650,6 +661,8 @@  static struct phy_driver broadcom_drivers[] = {
 	.name           = "Broadcom BCM54810",
 	.features       = PHY_GBIT_FEATURES,
 	.flags          = PHY_HAS_INTERRUPT,
+	.read_mmd	= bcm54810_read_mmd,
+	.write_mmd	= bcm54810_write_mmd,
 	.config_init    = bcm54xx_config_init,
 	.config_aneg    = bcm5481_config_aneg,
 	.read_status    = genphy_read_status,