[PATCH net-next v2] net: phy: broadcom: add 1000Base-X support for BCM54616S

From: Tao Ren
Date: Thu Aug 01 2019 - 20:01:05 EST


genphy_read_status() cannot report correct link speed when BCM54616S PHY
is configured in RGMII->1000Base-KX mode (for example, on Facebook CMM
BMC platform), and it is because speed-related fields in MII registers
are assigned different meanings in 1000X register set. Actually there
is no speed field in 1000X register set because link speed is always
1000 Mb/s.

The patch adds "probe" callback to detect PHY's operation mode based on
INTERF_SEL[1:0] pins and 1000X/100FX selection bit in SerDES 100-FX
Control register. Besides, link speed is manually set to 1000 Mb/s in
"read_status" callback if PHY-switch link is 1000Base-X.

Signed-off-by: Tao Ren <taoren@xxxxxx>
---
Changes in v2:
- Auto-detect PHY operation mode instead of passing DT node.
- move PHY mode auto-detect logic from config_init to probe callback.
- only set speed (not including duplex) in read_status callback.
- update patch description with more background to avoid confusion.
- patch #1 in the series ("net: phy: broadcom: set features explicitly
for BCM54616") is dropped: the fix should go to get_features callback
which may potentially depend on this patch.

drivers/net/phy/broadcom.c | 53 +++++++++++++++++++++++++++++++++++---
include/linux/brcmphy.h | 10 +++++--
2 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
index 937d0059e8ac..b6debbc6054e 100644
--- a/drivers/net/phy/broadcom.c
+++ b/drivers/net/phy/broadcom.c
@@ -383,9 +383,9 @@ static int bcm5482_config_init(struct phy_device *phydev)
/*
* Select 1000BASE-X register set (primary SerDes)
*/
- reg = bcm_phy_read_shadow(phydev, BCM5482_SHD_MODE);
- bcm_phy_write_shadow(phydev, BCM5482_SHD_MODE,
- reg | BCM5482_SHD_MODE_1000BX);
+ reg = bcm_phy_read_shadow(phydev, BCM54XX_SHD_MODE);
+ bcm_phy_write_shadow(phydev, BCM54XX_SHD_MODE,
+ reg | BCM54XX_SHD_MODE_1000BX);

/*
* LED1=ACTIVITYLED, LED3=LINKSPD[2]
@@ -464,6 +464,51 @@ static int bcm54616s_config_aneg(struct phy_device *phydev)
return ret;
}

+static int bcm54616s_probe(struct phy_device *phydev)
+{
+ int val, intf_sel;
+
+ val = bcm_phy_read_shadow(phydev, BCM54XX_SHD_MODE);
+ if (val < 0)
+ return val;
+
+ /* The PHY is strapped in RGMII to fiber mode when INTERF_SEL[1:0]
+ * is 01b.
+ */
+ intf_sel = (val & BCM54XX_SHD_INTF_SEL_MASK) >> 1;
+ if (intf_sel == 1) {
+ val = bcm_phy_read_shadow(phydev, BCM54616S_SHD_100FX_CTRL);
+ if (val < 0)
+ return val;
+
+ /* Bit 0 of the SerDes 100-FX Control register, when set
+ * to 1, sets the MII/RGMII -> 100BASE-FX configuration.
+ * When this bit is set to 0, it sets the GMII/RGMII ->
+ * 1000BASE-X configuration.
+ */
+ if (!(val & BCM54616S_100FX_MODE))
+ phydev->dev_flags |= PHY_BCM_FLAGS_MODE_1000BX;
+ }
+
+ return 0;
+}
+
+static int bcm54616s_read_status(struct phy_device *phydev)
+{
+ int err;
+
+ err = genphy_read_status(phydev);
+
+ /* 1000Base-X register set doesn't provide speed fields: the
+ * link speed is always 1000 Mb/s as long as link is up.
+ */
+ if (phydev->dev_flags & PHY_BCM_FLAGS_MODE_1000BX &&
+ phydev->link)
+ phydev->speed = SPEED_1000;
+
+ return err;
+}
+
static int brcm_phy_setbits(struct phy_device *phydev, int reg, int set)
{
int val;
@@ -655,6 +700,8 @@ static struct phy_driver broadcom_drivers[] = {
.config_aneg = bcm54616s_config_aneg,
.ack_interrupt = bcm_phy_ack_intr,
.config_intr = bcm_phy_config_intr,
+ .read_status = bcm54616s_read_status,
+ .probe = bcm54616s_probe,
}, {
.phy_id = PHY_ID_BCM5464,
.phy_id_mask = 0xfffffff0,
diff --git a/include/linux/brcmphy.h b/include/linux/brcmphy.h
index 6db2d9a6e503..b475e7f20d28 100644
--- a/include/linux/brcmphy.h
+++ b/include/linux/brcmphy.h
@@ -200,9 +200,15 @@
#define BCM5482_SHD_SSD 0x14 /* 10100: Secondary SerDes control */
#define BCM5482_SHD_SSD_LEDM 0x0008 /* SSD LED Mode enable */
#define BCM5482_SHD_SSD_EN 0x0001 /* SSD enable */
-#define BCM5482_SHD_MODE 0x1f /* 11111: Mode Control Register */
-#define BCM5482_SHD_MODE_1000BX 0x0001 /* Enable 1000BASE-X registers */

+/* 10011: SerDes 100-FX Control Register */
+#define BCM54616S_SHD_100FX_CTRL 0x13
+#define BCM54616S_100FX_MODE BIT(0) /* 100-FX SerDes Enable */
+
+/* 11111: Mode Control Register */
+#define BCM54XX_SHD_MODE 0x1f
+#define BCM54XX_SHD_INTF_SEL_MASK GENMASK(2, 1) /* INTERF_SEL[1:0] */
+#define BCM54XX_SHD_MODE_1000BX BIT(0) /* Enable 1000-X registers */

/*
* EXPANSION SHADOW ACCESS REGISTERS. (PHY REG 0x15, 0x16, and 0x17)
--
2.17.1