[PATCH net-next v8 3/3] net: phy: broadcom: add 1000Base-X support for BCM54616S

From: Tao Ren
Date: Mon Sep 09 2019 - 16:52:07 EST

The BCM54616S PHY cannot work properly in RGMII->1000Base-X mode, mainly
because genphy functions are designed for copper links, and 1000Base-X
(clause 37) auto negotiation needs to be handled differently.

This patch enables 1000Base-X support for BCM54616S by customizing 3
driver callbacks, and it's verified to be working on Facebook CMM BMC
platform (RGMII->1000Base-KX):

- probe: probe callback detects PHY's operation mode based on
INTERF_SEL[1:0] pins and 1000X/100FX selection bit in SerDES 100-FX
Control register.

- config_aneg: calls genphy_c37_config_aneg when the PHY is running in
1000Base-X mode; otherwise, genphy_config_aneg will be called.

- read_status: calls genphy_c37_read_status when the PHY is running in
1000Base-X mode; otherwise, genphy_read_status will be called.

Note: BCM54616S PHY can also be configured in RGMII->100Base-FX mode, and
100Base-FX support is not available as of now.

Signed-off-by: Tao Ren <taoren@xxxxxx>
Acked-by: Vladimir Oltean <olteanv@xxxxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
No changes in v8.
Changes in v7:
- Add comment "BCM54616S 100Base-FX is not supported".
Changes in v6:
- nothing changed.
Changes in v5:
- include Heiner's patch "net: phy: add support for clause 37
auto-negotiation" into the series.
- use genphy_c37_config_aneg and genphy_c37_read_status in BCM54616S
PHY driver's callback when the PHY is running in 1000Base-X mode.
Changes in v4:
- add bcm54616s_config_aneg_1000bx() to deal with auto negotiation in
1000Base-X mode.
Changes in v3:
- rename bcm5482_read_status to bcm54xx_read_status so the callback can
be shared by BCM5482 and BCM54616S.
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.

drivers/net/phy/broadcom.c | 57 +++++++++++++++++++++++++++++++++++---
include/linux/brcmphy.h | 10 +++++--
2 files changed, 61 insertions(+), 6 deletions(-)

diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
index 937d0059e8ac..5fd9293513d8 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]
@@ -451,12 +451,47 @@ static int bcm5481_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-fiber mode when INTERF_SEL[1:0]
+ * is 01b, and the link between PHY and its link partner can be
+ * either 1000Base-X or 100Base-FX.
+ * RGMII-1000Base-X is properly supported, but RGMII-100Base-FX
+ * support is still missing as of now.
+ */
+ 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_config_aneg(struct phy_device *phydev)
{
int ret;

/* Aneg firsly. */
- ret = genphy_config_aneg(phydev);
+ if (phydev->dev_flags & PHY_BCM_FLAGS_MODE_1000BX)
+ ret = genphy_c37_config_aneg(phydev);
+ else
+ ret = genphy_config_aneg(phydev);

/* Then we can set up the delay. */
bcm54xx_config_clock_delay(phydev);
@@ -464,6 +499,18 @@ static int bcm54616s_config_aneg(struct phy_device *phydev)
return ret;
}

+static int bcm54616s_read_status(struct phy_device *phydev)
+{
+ int err;
+
+ if (phydev->dev_flags & PHY_BCM_FLAGS_MODE_1000BX)
+ err = genphy_c37_read_status(phydev);
+ else
+ err = genphy_read_status(phydev);
+
+ return err;
+}
+
static int brcm_phy_setbits(struct phy_device *phydev, int reg, int set)
{
int val;
@@ -655,6 +702,8 @@ 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