This is a note to let you know that I've just added the patch titled
net: dsa: vsc73xx: check busy flag in MDIO operations
to the 6.6-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-check-busy-flag-in-mdio-operations.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e3b3bc1e22a96c0c77e96327911f9f990912fdec
Author: Pawel Dembicki <paweldembicki@xxxxxxxxx>
Date: Fri Aug 9 21:38:04 2024 +0200
net: dsa: vsc73xx: check busy flag in MDIO operations
[ Upstream commit fa63c6434b6f6aaf9d8d599dc899bc0a074cc0ad ]
The VSC73xx has a busy flag used during MDIO operations. It is raised
when MDIO read/write operations are in progress. Without it, PHYs are
misconfigured and bus operations do not work as expected.
Fixes: 05bd97fc559d ("net: dsa: Add Vitesse VSC73xx DSA router driver")
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
Signed-off-by: Pawel Dembicki <paweldembicki@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
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 d8f368df8b06f..23bd8b3f89931 100644
--- a/drivers/net/dsa/vitesse-vsc73xx-core.c
+++ b/drivers/net/dsa/vitesse-vsc73xx-core.c
@@ -38,6 +38,10 @@
#define VSC73XX_BLOCK_ARBITER 0x5 /* Only subblock 0 */
#define VSC73XX_BLOCK_SYSTEM 0x7 /* Only subblock 0 */
+/* MII Block subblock */
+#define VSC73XX_BLOCK_MII_INTERNAL 0x0 /* Internal MDIO subblock */
+#define VSC73XX_BLOCK_MII_EXTERNAL 0x1 /* External MDIO subblock */
+
#define CPU_PORT 6 /* CPU port */
/* MAC Block registers */
@@ -196,6 +200,8 @@
#define VSC73XX_MII_CMD 0x1
#define VSC73XX_MII_DATA 0x2
+#define VSC73XX_MII_STAT_BUSY BIT(3)
+
/* Arbiter block 5 registers */
#define VSC73XX_ARBEMPTY 0x0c
#define VSC73XX_ARBDISC 0x0e
@@ -270,6 +276,7 @@
#define IS_739X(a) (IS_7395(a) || IS_7398(a))
#define VSC73XX_POLL_SLEEP_US 1000
+#define VSC73XX_MDIO_POLL_SLEEP_US 5
#define VSC73XX_POLL_TIMEOUT_US 10000
struct vsc73xx_counter {
@@ -487,6 +494,22 @@ static int vsc73xx_detect(struct vsc73xx *vsc)
return 0;
}
+static int vsc73xx_mdio_busy_check(struct vsc73xx *vsc)
+{
+ int ret, err;
+ u32 val;
+
+ ret = read_poll_timeout(vsc73xx_read, err,
+ err < 0 || !(val & VSC73XX_MII_STAT_BUSY),
+ VSC73XX_MDIO_POLL_SLEEP_US,
+ VSC73XX_POLL_TIMEOUT_US, false, vsc,
+ VSC73XX_BLOCK_MII, VSC73XX_BLOCK_MII_INTERNAL,
+ VSC73XX_MII_STAT, &val);
+ if (ret)
+ return ret;
+ return err;
+}
+
static int vsc73xx_phy_read(struct dsa_switch *ds, int phy, int regnum)
{
struct vsc73xx *vsc = ds->priv;
@@ -494,12 +517,20 @@ static int vsc73xx_phy_read(struct dsa_switch *ds, int phy, int regnum)
u32 val;
int ret;
+ ret = vsc73xx_mdio_busy_check(vsc);
+ if (ret)
+ return ret;
+
/* Setting bit 26 means "read" */
cmd = BIT(26) | (phy << 21) | (regnum << 16);
ret = vsc73xx_write(vsc, VSC73XX_BLOCK_MII, 0, 1, cmd);
if (ret)
return ret;
- msleep(2);
+
+ ret = vsc73xx_mdio_busy_check(vsc);
+ if (ret)
+ return ret;
+
ret = vsc73xx_read(vsc, VSC73XX_BLOCK_MII, 0, 2, &val);
if (ret)
return ret;
@@ -523,6 +554,10 @@ static int vsc73xx_phy_write(struct dsa_switch *ds, int phy, int regnum,
u32 cmd;
int ret;
+ ret = vsc73xx_mdio_busy_check(vsc);
+ if (ret)
+ return ret;
+
/* It was found through tedious experiments that this router
* chip really hates to have it's PHYs reset. They
* never recover if that happens: autonegotiation stops
