Re: Re: Re: [PATCH v2] net: mtk_sgmii: implement mtk_pcs_ops

From: Russell King (Oracle)
Date: Mon Oct 24 2022 - 05:28:23 EST


On Sun, Oct 23, 2022 at 09:09:23PM +0100, Russell King (Oracle) wrote:
> This is amazingly great news - we now know how to configure this
> hardware! Let me cook up a proper set of patches for tomorrow - if
> that's okay.

Here's the combined patch for where I would like mtk_sgmii to get to.

It looks like this PCS is similar to what we know as pcs-lynx.c, but
there do seem to be differences - the duplex bit for example appears
to be inverted.

Please confirm whether this still works for you, thanks.

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index b52f3b0177ef..8ecf97bcfec6 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -466,8 +466,10 @@
#define ETHSYS_DMA_AG_MAP_PPE BIT(2)

/* SGMII subsystem config registers */
-/* Register to auto-negotiation restart */
+/* BMCR (low 16) BMSR (high 16) */
#define SGMSYS_PCS_CONTROL_1 0x0
+#define SGMII_BMCR GENMASK(15, 0)
+#define SGMII_BMSR GENMASK(31, 16)
#define SGMII_AN_RESTART BIT(9)
#define SGMII_ISOLATE BIT(10)
#define SGMII_AN_ENABLE BIT(12)
@@ -477,9 +479,13 @@
#define SGMII_PCS_FAULT BIT(23)
#define SGMII_AN_EXPANSION_CLR BIT(30)

+#define SGMSYS_PCS_ADVERTISE 0x8
+#define SGMII_ADVERTISE GENMASK(15, 0)
+#define SGMII_LPA GENMASK(31, 16)
+
/* Register to programmable link timer, the unit in 2 * 8ns */
#define SGMSYS_PCS_LINK_TIMER 0x18
-#define SGMII_LINK_TIMER_DEFAULT (0x186a0 & GENMASK(19, 0))
+#define SGMII_LINK_TIMER_MASK GENMASK(19, 0)

/* Register to control remote fault */
#define SGMSYS_SGMII_MODE 0x20
diff --git a/drivers/net/ethernet/mediatek/mtk_sgmii.c b/drivers/net/ethernet/mediatek/mtk_sgmii.c
index 736839c84130..e64c02a48449 100644
--- a/drivers/net/ethernet/mediatek/mtk_sgmii.c
+++ b/drivers/net/ethernet/mediatek/mtk_sgmii.c
@@ -19,110 +19,136 @@ static struct mtk_pcs *pcs_to_mtk_pcs(struct phylink_pcs *pcs)
return container_of(pcs, struct mtk_pcs, pcs);
}

-/* For SGMII interface mode */
-static int mtk_pcs_setup_mode_an(struct mtk_pcs *mpcs)
+static void mtk_pcs_get_state(struct phylink_pcs *pcs,
+ struct phylink_link_state *state)
{
- unsigned int val;
-
- /* Setup the link timer and QPHY power up inside SGMIISYS */
- regmap_write(mpcs->regmap, SGMSYS_PCS_LINK_TIMER,
- SGMII_LINK_TIMER_DEFAULT);
-
- regmap_read(mpcs->regmap, SGMSYS_SGMII_MODE, &val);
- val |= SGMII_REMOTE_FAULT_DIS;
- regmap_write(mpcs->regmap, SGMSYS_SGMII_MODE, val);
-
- regmap_read(mpcs->regmap, SGMSYS_PCS_CONTROL_1, &val);
- val |= SGMII_AN_RESTART;
- regmap_write(mpcs->regmap, SGMSYS_PCS_CONTROL_1, val);
-
- regmap_read(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, &val);
- val &= ~SGMII_PHYA_PWD;
- regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, val);
+ struct mtk_pcs *mpcs = pcs_to_mtk_pcs(pcs);
+ unsigned int bm, adv;

- return 0;
+ /* Read the BMSR and LPA */
+ regmap_read(mpcs->regmap, SGMSYS_PCS_CONTROL_1, &bm);
+ regmap_read(mpcs->regmap, SGMSYS_PCS_ADVERTISE, &adv);

+ phylink_mii_c22_pcs_decode_state(state, FIELD_GET(SGMII_BMSR, bm),
+ FIELD_GET(SGMII_LPA, adv));
}

-/* For 1000BASE-X and 2500BASE-X interface modes, which operate at a
- * fixed speed.
- */
-static int mtk_pcs_setup_mode_force(struct mtk_pcs *mpcs,
- phy_interface_t interface)
+static int mtk_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
+ phy_interface_t interface,
+ const unsigned long *advertising,
+ bool permit_pause_to_mac)
{
- unsigned int val;
+ struct mtk_pcs *mpcs = pcs_to_mtk_pcs(pcs);
+ unsigned int rgc3, sgm_mode, bmcr;
+ int advertise, link_timer;
+ bool changed, use_an;

- regmap_read(mpcs->regmap, mpcs->ana_rgc3, &val);
- val &= ~RG_PHY_SPEED_MASK;
if (interface == PHY_INTERFACE_MODE_2500BASEX)
- val |= RG_PHY_SPEED_3_125G;
- regmap_write(mpcs->regmap, mpcs->ana_rgc3, val);
+ rgc3 = RG_PHY_SPEED_3_125G;
+ else
+ rgc3 = 0;
+
+ advertise = phylink_mii_c22_pcs_encode_advertisement(interface,
+ advertising);
+ if (advertise < 0)
+ return advertise;
+
+ link_timer = phylink_get_link_timer_ns(interface);
+ if (link_timer < 0)
+ return link_timer;
+
+ /* Clearing IF_MODE_BIT0 switches the PCS to BASE-X mode, and
+ * we assume that fixes it's speed at bitrate = line rate (in
+ * other words, 1000Mbps or 2500Mbps).
+ */
+ if (interface == PHY_INTERFACE_MODE_SGMII) {
+ sgm_mode = SGMII_IF_MODE_BIT0;
+ if (phylink_autoneg_inband(mode)) {
+ sgm_mode |= SGMII_REMOTE_FAULT_DIS |
+ SGMII_SPEED_DUPLEX_AN;
+ use_an = true;
+ } else {
+ use_an = false;
+ }
+ } else if (phylink_autoneg_inband(mode)) {
+ /* 1000base-X or 2500base-X autoneg */
+ sgm_mode = SGMII_REMOTE_FAULT_DIS;
+ use_an = linkmode_test_bit(ETHTOOL_LINK_MODE_Autoneg_BIT,
+ advertising);
+ } else {
+ /* 1000base-X or 2500base-X without autoneg */
+ sgm_mode = 0;
+ use_an = false;
+ }

- /* Disable SGMII AN */
- regmap_read(mpcs->regmap, SGMSYS_PCS_CONTROL_1, &val);
- val &= ~SGMII_AN_ENABLE;
- regmap_write(mpcs->regmap, SGMSYS_PCS_CONTROL_1, val);
+ if (use_an) {
+ /* FIXME: Do we need to set AN_RESTART here? */
+ bmcr = SGMII_AN_RESTART | SGMII_AN_ENABLE;
+ } else {
+ bmcr = 0;
+ }

- /* Set the speed etc but leave the duplex unchanged */
- regmap_read(mpcs->regmap, SGMSYS_SGMII_MODE, &val);
- val &= SGMII_DUPLEX_FULL | ~SGMII_IF_MODE_MASK;
- val |= SGMII_SPEED_1000;
- regmap_write(mpcs->regmap, SGMSYS_SGMII_MODE, val);
+ /* Configure the underlying interface speed */
+ regmap_update_bits(mpcs->regmap, mpcs->ana_rgc3,
+ RG_PHY_SPEED_3_125G, rgc3);

- /* Release PHYA power down state */
- regmap_read(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, &val);
- val &= ~SGMII_PHYA_PWD;
- regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, val);
+ /* Update the advertisement, noting whether it has changed */
+ regmap_update_bits_check(mpcs->regmap, SGMSYS_PCS_ADVERTISE,
+ SGMII_ADVERTISE, advertise, &changed);

- return 0;
-}
+ /* Setup the link timer and QPHY power up inside SGMIISYS */
+ regmap_write(mpcs->regmap, SGMSYS_PCS_LINK_TIMER, link_timer / 2 / 8);

-static int mtk_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
- phy_interface_t interface,
- const unsigned long *advertising,
- bool permit_pause_to_mac)
-{
- struct mtk_pcs *mpcs = pcs_to_mtk_pcs(pcs);
- int err = 0;
+ /* Update the sgmsys mode register */
+ regmap_update_bits(mpcs->regmap, SGMSYS_SGMII_MODE,
+ SGMII_REMOTE_FAULT_DIS | SGMII_SPEED_DUPLEX_AN |
+ SGMII_IF_MODE_BIT0, sgm_mode);
+
+ /* Update the BMCR */
+ regmap_update_bits(mpcs->regmap, SGMSYS_PCS_CONTROL_1,
+ SGMII_AN_RESTART | SGMII_AN_ENABLE, bmcr);

- /* Setup SGMIISYS with the determined property */
- if (interface != PHY_INTERFACE_MODE_SGMII)
- err = mtk_pcs_setup_mode_force(mpcs, interface);
- else if (phylink_autoneg_inband(mode))
- err = mtk_pcs_setup_mode_an(mpcs);
+ /* Release PHYA power down state */
+ regmap_update_bits(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL,
+ SGMII_PHYA_PWD, 0);

- return err;
+ return changed ? 1 : 0;
}

static void mtk_pcs_restart_an(struct phylink_pcs *pcs)
{
struct mtk_pcs *mpcs = pcs_to_mtk_pcs(pcs);
- unsigned int val;

- regmap_read(mpcs->regmap, SGMSYS_PCS_CONTROL_1, &val);
- val |= SGMII_AN_RESTART;
- regmap_write(mpcs->regmap, SGMSYS_PCS_CONTROL_1, val);
+ regmap_update_bits(mpcs->regmap, SGMSYS_PCS_CONTROL_1,
+ SGMII_AN_RESTART, SGMII_AN_RESTART);
}

static void mtk_pcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
phy_interface_t interface, int speed, int duplex)
{
struct mtk_pcs *mpcs = pcs_to_mtk_pcs(pcs);
- unsigned int val;
-
- if (!phy_interface_mode_is_8023z(interface))
- return;
-
- /* SGMII force duplex setting */
- regmap_read(mpcs->regmap, SGMSYS_SGMII_MODE, &val);
- val &= ~SGMII_DUPLEX_FULL;
- if (duplex == DUPLEX_FULL)
- val |= SGMII_DUPLEX_FULL;
-
- regmap_write(mpcs->regmap, SGMSYS_SGMII_MODE, val);
+ unsigned int sgm_mode;
+
+ if (!phylink_autoneg_inband(mode)) {
+ /* Force the speed and duplex setting */
+ if (speed == SPEED_10)
+ sgm_mode = SGMII_SPEED_10;
+ else if (speed == SPEED_100)
+ sgm_mode = SGMII_SPEED_100;
+ else
+ sgm_mode = SGMII_SPEED_1000;
+
+ if (duplex == DUPLEX_FULL)
+ sgm_mode |= SGMII_DUPLEX_FULL;
+
+ regmap_update_bits(mpcs->regmap, SGMSYS_SGMII_MODE,
+ SGMII_DUPLEX_FULL | SGMII_SPEED_MASK,
+ sgm_mode);
+ }
}

static const struct phylink_pcs_ops mtk_pcs_ops = {
+ .pcs_get_state = mtk_pcs_get_state,
.pcs_config = mtk_pcs_config,
.pcs_an_restart = mtk_pcs_restart_an,
.pcs_link_up = mtk_pcs_link_up,
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index 63800bf4a7ac..7a3eb46b38c1 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -616,6 +616,22 @@ int phylink_speed_up(struct phylink *pl);

void phylink_set_port_modes(unsigned long *bits);

+static inline int phylink_get_link_timer_ns(phy_interface_t interface)
+{
+ switch (interface) {
+ case PHY_INTERFACE_MODE_SGMII:
+ case PHY_INTERFACE_MODE_QSGMII:
+ return 1600000;
+
+ case PHY_INTERFACE_MODE_1000BASEX:
+ case PHY_INTERFACE_MODE_2500BASEX:
+ return 10000000;
+
+ default:
+ return -EINVAL;
+ }
+}
+
void phylink_mii_c22_pcs_decode_state(struct phylink_link_state *state,
u16 bmsr, u16 lpa);
void phylink_mii_c22_pcs_get_state(struct mdio_device *pcs,

--
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