diff mbox series

[RFC,6/8] net: pcs: add driver for MediaTek USXGMII PCS

Message ID b9f787f3e4aa36e148d7595495af60db53f74417.1699565880.git.daniel@makrotopia.org (mailing list archive)
State RFC
Delegated to: Netdev Maintainers
Headers show
Series Add support for 10G Ethernet SerDes on MT7988 | expand

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Commit Message

Daniel Golle Nov. 9, 2023, 9:51 p.m. UTC
Add driver for USXGMII PCS found in the MediaTek MT7988 SoC and supporting
USXGMII, 10GBase-R and 5GBase-R interface modes. In order to support
Cisco SGMII, 1000Base-X and 2500Base-X via the also present LynxI PCS
create a wrapped PCS taking care of the components shared between the
new USXGMII PCS and the legacy LynxI PCS.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 MAINTAINERS                         |   2 +
 drivers/net/pcs/Kconfig             |  10 +
 drivers/net/pcs/Makefile            |   1 +
 drivers/net/pcs/pcs-mtk-usxgmii.c   | 688 ++++++++++++++++++++++++++++
 include/linux/pcs/pcs-mtk-usxgmii.h |  18 +
 5 files changed, 719 insertions(+)
 create mode 100644 drivers/net/pcs/pcs-mtk-usxgmii.c
 create mode 100644 include/linux/pcs/pcs-mtk-usxgmii.h

Comments

Philipp Zabel Nov. 27, 2023, 1:25 p.m. UTC | #1
On Do, 2023-11-09 at 21:51 +0000, Daniel Golle wrote:
> Add driver for USXGMII PCS found in the MediaTek MT7988 SoC and supporting
> USXGMII, 10GBase-R and 5GBase-R interface modes. In order to support
> Cisco SGMII, 1000Base-X and 2500Base-X via the also present LynxI PCS
> create a wrapped PCS taking care of the components shared between the
> new USXGMII PCS and the legacy LynxI PCS.
> 
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>
> ---
[...]
> diff --git a/drivers/net/pcs/pcs-mtk-usxgmii.c b/drivers/net/pcs/pcs-mtk-usxgmii.c
> new file mode 100644
> index 0000000000000..b3ca66c9df2a9
> --- /dev/null
> +++ b/drivers/net/pcs/pcs-mtk-usxgmii.c
> @@ -0,0 +1,688 @@
[...]
> +static int mtk_sgmii_wrapper_init(struct mtk_usxgmii_pcs *mpcs)
> +{
> +	struct device_node *r = mpcs->dev->of_node, *np;
[...]
> +	rstc = of_reset_control_get_shared(r, "sgmii");
> +

Superfluous whitespace.

> +	if (IS_ERR(rstc))
> +		return PTR_ERR(rstc);

Here you correctly check rstc for errors ...

[...]
> +	wp->reset = rstc;
[...]
> +
> +	if (IS_ERR(wp->reset))
> +		return PTR_ERR(wp->reset);

And here you check it again. The second check can be dropped.


regards
Philipp
Russell King (Oracle) Nov. 27, 2023, 3:08 p.m. UTC | #2
On Thu, Nov 09, 2023 at 09:51:57PM +0000, Daniel Golle wrote:
> Add driver for USXGMII PCS found in the MediaTek MT7988 SoC and supporting
> USXGMII, 10GBase-R and 5GBase-R interface modes. In order to support
> Cisco SGMII, 1000Base-X and 2500Base-X via the also present LynxI PCS
> create a wrapped PCS taking care of the components shared between the
> new USXGMII PCS and the legacy LynxI PCS.

What is the actual hardware setup here?

From what I can tell, it's something like this:

         .---- LynxI PCS ----.
 MAC ---+                     +--- PEXP --- external
         `--- USXGMII PCS ---'

Where PEXP is the serdes, handled by the drivers/phy layer in the
kernel. This is not an unusual setup, but we don't have the serdes PHY
controlled by the PCS driver.

You seem to be combining the whole lot into one driver, which seems
rather odd.

I would suggest that the serdes PHY is handled in the MAC driver, using
the mac_prepare(), mac_config() and mac_finish() methods, as well as
other parts of the driver:

- when the netdev is opened, call phy_power_on(pextp)
- when the netdev is closed, call phy_power_off(pextp)
- in mac_prepare(), if the interface has changed, call phy_reset(pextp)
- in mac_finish(), if the interface has changed, update your recorded
  interface mode to detect future changes in either mac_prepare() or
  mac_finish(), and call phy_set_mode_ext(pextp, PHY_MODE_ETHERNET,
  interface).

That will move most of what seems to be duplicated between the two PCS
instances out of the PCS driver and to MAC level, and then the PCS parts
become more about just driving the PCS hardware and nothing beyond that.
More specifically, the wrapping's only function then is to deal with the
sgmii reset. What exactly is that reset signal controlling? The reset to
the LynxI PCS or something else?

If you don't do that (and I prefer that you _do_ the above), then the
following comments apply to the code here:

1. the use of phy_power_on() without any calls to phy_power_off().
   These are counted calls, and after the first call to phy_power_on(),
   the only effect will be to increase the enable-counts of any
   associated regulator and the power count. So, basically you're
   missing calls to phy_power_off(). I suggest a call to phy_power_off()
   in the pcs_disable() function.

2. calling phy_power_on() in pcs_config() is entirely unnecessary.
   pcs_config() will not be called unless pcs_enable() has _already_
   been called, so the call to phy_power_on() in the pcs_enable()
   function is entirely sufficient.

With these two fixed, it means that the pextp PHY will be powered up
when one of the pcs_enable() functions is called, and powered down
when one of the pcs_disable() functions is called.

3. the complicated reset sequence, which is basically:
   - phy_reset(pextp)
   - reset_control_assert(sgmii or xfi reset)
   - *sleep* 100-500us (yes, sleep)
   - reset_control_deassert(sgmii or xfi reset)
   - *delay* 10ms (not sleep, but spin wait)
   If we are in a schedulable context (which the usleep_range() suggests
   we are) then why bother sleeping for the short delay, and
   spin-waiting for the longer delay? A bit of consistency seems to be
   needed here.

4. really needs to explain why it's necessary to repeatedly call the
   pcs_config() function at each get_state() if the link is down.

   Note that with the code the way it is, phy_power_on() will be
   repeatedly called, and at some point the "power_count" will overflow
   which would probably be bad. The counting in the regulator core will
   probably also overflow as well. So this is bad.

   Apart from the overflow issue, the only thing I can see that this
   achieves is to call the core of the pcs_config function. In the case
   of the lynxi, calling its pcs_config() repeatedly with the same
   parameters. Looking at pcs-mtk-lynxi.c, I can't see what this would
   achieve.

With the above issues dealt with, from the point of view of the lynxi /
sgmii code, the only things I can see that the wrapping achieves are:

a) when pcs_enable() is called, call phy_power_on(pextp)
b) when pcs_disable() is called, call phy_power_offpextp)
c) when pcs_config() is called, if the interface has changed:
   i)  call phy_reset() and assert/deassert the "sgmii" reset before
       calling the lynxi PCS
   ii) call phy_set_mode_ext(pextp) for the new interface mode after
       calling the lynxi PCS

I haven't picked through the usxgmii code completely, so I'm not
specifically commenting on it, although some of the above applies
there as well.

Thanks.
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 6499acd8f3874..026f62243f595 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13517,7 +13517,9 @@  M:	Daniel Golle <daniel@makrotopia.org>
 L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/pcs/pcs-mtk-lynxi.c
+F:	drivers/net/pcs/pcs-mtk-usxgmii.c
 F:	include/linux/pcs/pcs-mtk-lynxi.h
+F:	include/linux/pcs/pcs-mtk-usxgmii.h
 
 MEDIATEK ETHERNET PHY DRIVERS
 M:	Daniel Golle <daniel@makrotopia.org>
diff --git a/drivers/net/pcs/Kconfig b/drivers/net/pcs/Kconfig
index 87cf308fc6d8b..5df5b19c4eb93 100644
--- a/drivers/net/pcs/Kconfig
+++ b/drivers/net/pcs/Kconfig
@@ -25,6 +25,16 @@  config PCS_MTK_LYNXI
 	  This module provides helpers to phylink for managing the LynxI PCS
 	  which is part of MediaTek's SoC and Ethernet switch ICs.
 
+config PCS_MTK_USXGMII
+	tristate "MediaTek USXGMII PCS"
+	select PCS_MTK_LYNXI
+	select PHY_MTK_PEXTP
+	help
+	  This module provides a driver for MediaTek's USXGMII PCS supporting
+	  10GBase-R, 5GBase-R and USXGMII interface modes.
+	  1000Base-X, 2500Base-X and Cisco SGMII are supported on the same
+	  differential pairs via an embedded LynxI PHY.
+
 config PCS_RZN1_MIIC
 	tristate "Renesas RZ/N1 MII converter"
 	depends on OF && (ARCH_RZN1 || COMPILE_TEST)
diff --git a/drivers/net/pcs/Makefile b/drivers/net/pcs/Makefile
index fb1694192ae63..cc355152ca1ca 100644
--- a/drivers/net/pcs/Makefile
+++ b/drivers/net/pcs/Makefile
@@ -6,4 +6,5 @@  pcs_xpcs-$(CONFIG_PCS_XPCS)	:= pcs-xpcs.o pcs-xpcs-nxp.o pcs-xpcs-wx.o
 obj-$(CONFIG_PCS_XPCS)		+= pcs_xpcs.o
 obj-$(CONFIG_PCS_LYNX)		+= pcs-lynx.o
 obj-$(CONFIG_PCS_MTK_LYNXI)	+= pcs-mtk-lynxi.o
+obj-$(CONFIG_PCS_MTK_USXGMII)	+= pcs-mtk-usxgmii.o
 obj-$(CONFIG_PCS_RZN1_MIIC)	+= pcs-rzn1-miic.o
diff --git a/drivers/net/pcs/pcs-mtk-usxgmii.c b/drivers/net/pcs/pcs-mtk-usxgmii.c
new file mode 100644
index 0000000000000..b3ca66c9df2a9
--- /dev/null
+++ b/drivers/net/pcs/pcs-mtk-usxgmii.c
@@ -0,0 +1,688 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ * Author: Henry Yen <henry.yen@mediatek.com>
+ *         Daniel Golle <daniel@makrotopia.org>
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mdio.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/pcs/pcs-mtk-lynxi.h>
+#include <linux/pcs/pcs-mtk-usxgmii.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+
+/* USXGMII subsystem config registers */
+/* Register to control speed */
+#define RG_PHY_TOP_SPEED_CTRL1			0x80c
+#define USXGMII_RATE_UPDATE_MODE		BIT(31)
+#define USXGMII_MAC_CK_GATED			BIT(29)
+#define USXGMII_IF_FORCE_EN			BIT(28)
+#define USXGMII_RATE_ADAPT_MODE			GENMASK(10, 8)
+#define USXGMII_RATE_ADAPT_MODE_X1		0
+#define USXGMII_RATE_ADAPT_MODE_X2		1
+#define USXGMII_RATE_ADAPT_MODE_X4		2
+#define USXGMII_RATE_ADAPT_MODE_X10		3
+#define USXGMII_RATE_ADAPT_MODE_X100		4
+#define USXGMII_RATE_ADAPT_MODE_X5		5
+#define USXGMII_RATE_ADAPT_MODE_X50		6
+#define USXGMII_XFI_RX_MODE			GENMASK(6, 4)
+#define USXGMII_XFI_TX_MODE			GENMASK(2, 0)
+#define USXGMII_XFI_MODE_10G			0
+#define USXGMII_XFI_MODE_5G			1
+#define USXGMII_XFI_MODE_2P5G			3
+
+/* Register to control PCS AN */
+#define RG_PCS_AN_CTRL0				0x810
+#define USXGMII_AN_RESTART			BIT(31)
+#define USXGMII_AN_SYNC_CNT			GENMASK(30, 11)
+#define USXGMII_AN_ENABLE			BIT(0)
+
+#define RG_PCS_AN_CTRL2				0x818
+#define USXGMII_LINK_TIMER_IDLE_DETECT		GENMASK(29, 20)
+#define USXGMII_LINK_TIMER_COMP_ACK_DETECT	GENMASK(19, 10)
+#define USXGMII_LINK_TIMER_AN_RESTART		GENMASK(9, 0)
+
+/* Register to read PCS AN status */
+#define RG_PCS_AN_STS0				0x81c
+#define USXGMII_LPA				GENMASK(15, 0)
+#define USXGMII_LPA_LATCH			BIT(31)
+
+/* Register to read PCS link status */
+#define RG_PCS_RX_STATUS0			0x904
+#define RG_PCS_RX_STATUS_UPDATE			BIT(16)
+#define RG_PCS_RX_LINK_STATUS			BIT(2)
+
+#define MTK_NETSYS_V3_AMA_RGC3			0x128
+
+/* struct mtk_usxgmii_pcs - This structure holds each usxgmii PCS
+ * @pcs:		Phylink PCS structure
+ * @dev:		Pointer to device structure
+ * @base:		IO memory to access PCS hardware
+ * @clk:		Pointer to USXGMII clk
+ * @xfi_pll:		Pointer to XFI PLL clk
+ * @pextp:		The PHYA instance attached to the PCS
+ * @reset:		Pointer to USXGMII reset control
+ * @interface:		Currently selected interface mode
+ * @neg_mode:		Currently used phylink neg_mode
+ */
+struct mtk_usxgmii_pcs {
+	struct phylink_pcs		pcs;
+	struct phylink_pcs		*sgmii_pcs;
+	struct device			*dev;
+	void __iomem			*base;
+	struct clk			*clk;
+	struct clk			*xfi_pll;
+	struct phy			*pextp;
+	struct reset_control		*reset;
+	struct regmap			*regmap_pll;
+	phy_interface_t			interface;
+	unsigned int			neg_mode;
+};
+
+/* struct mtk_sgmii_wrapper_pcs - Structure holding wrapped SGMII PCS
+ * @usxgmii_pcs		Pointer to owning mtk_usxgmii_pcs structure
+ * @pcs			Phylink PCS structure
+ * @clks:		Pointers to 3 SGMII clks
+ * @reset:		Pointer to SGMII reset control
+ * @interface:		Currently selected interface mode
+ * @neg_mode:		Currently used phylink neg_mode
+ */
+struct mtk_sgmii_wrapper_pcs {
+	struct mtk_usxgmii_pcs		*usxgmii_pcs;
+	struct phylink_pcs		*lynxi_pcs;
+	struct phylink_pcs		pcs;
+	struct clk			*clks[3];
+	struct reset_control		*reset;
+	phy_interface_t			interface;
+	unsigned int			neg_mode;
+	bool				permit_pause_to_mac;
+};
+
+static u32 mtk_r32(struct mtk_usxgmii_pcs *mpcs, unsigned int reg)
+{
+	return ioread32(mpcs->base + reg);
+}
+
+static void mtk_m32(struct mtk_usxgmii_pcs *mpcs, unsigned int reg, u32 mask, u32 set)
+{
+	u32 val;
+
+	val = ioread32(mpcs->base + reg);
+	val &= ~mask;
+	val |= set;
+	iowrite32(val, mpcs->base + reg);
+}
+
+static struct mtk_usxgmii_pcs *pcs_to_mtk_usxgmii_pcs(struct phylink_pcs *pcs)
+{
+	return container_of(pcs, struct mtk_usxgmii_pcs, pcs);
+}
+
+static int mtk_xfi_pextp_init(struct mtk_usxgmii_pcs *mpcs)
+{
+	struct device *dev = mpcs->dev;
+
+	mpcs->pextp = devm_phy_get(dev, NULL);
+	if (IS_ERR(mpcs->pextp))
+		return dev_err_probe(dev, PTR_ERR(mpcs->pextp), "cannot acquire PHYA\n");
+
+	if (!mpcs->pextp)
+		return dev_err_probe(dev, -ENODEV, "PHYA not found\n");
+
+	return 0;
+}
+
+static void mtk_usxgmii_reset(struct mtk_usxgmii_pcs *mpcs)
+{
+	if (!mpcs->pextp)
+		return;
+
+	phy_reset(mpcs->pextp);
+
+	reset_control_assert(mpcs->reset);
+	usleep_range(100, 500);
+	reset_control_deassert(mpcs->reset);
+
+	mdelay(10);
+}
+
+static void mtk_sgmii_reset(struct mtk_sgmii_wrapper_pcs *wp)
+{
+	if (!wp->usxgmii_pcs->pextp)
+		return;
+
+	phy_reset(wp->usxgmii_pcs->pextp);
+
+	reset_control_assert(wp->reset);
+	usleep_range(100, 500);
+	reset_control_deassert(wp->reset);
+
+	mdelay(10);
+}
+
+static int mtk_sgmii_wrapped_pcs_config(struct phylink_pcs *pcs,
+					unsigned int neg_mode,
+					phy_interface_t interface,
+					const unsigned long *advertising,
+					bool permit_pause_to_mac)
+{
+	struct mtk_sgmii_wrapper_pcs *wp = container_of(pcs, struct mtk_sgmii_wrapper_pcs, pcs);
+	bool full_reconf;
+	int ret;
+
+	phy_power_on(wp->usxgmii_pcs->pextp);
+
+	full_reconf = (interface != wp->interface);
+	if (full_reconf)
+		mtk_sgmii_reset(wp);
+
+	ret = wp->lynxi_pcs->ops->pcs_config(wp->lynxi_pcs, neg_mode, interface, advertising,
+					     permit_pause_to_mac);
+
+	if (full_reconf)
+		phy_set_mode_ext(wp->usxgmii_pcs->pextp, PHY_MODE_ETHERNET, interface);
+
+	wp->interface = interface;
+	wp->neg_mode = neg_mode;
+	wp->permit_pause_to_mac = permit_pause_to_mac;
+
+	return ret;
+}
+
+static void mtk_sgmii_wrapped_pcs_get_state(struct phylink_pcs *pcs,
+					    struct phylink_link_state *state)
+{
+	struct mtk_sgmii_wrapper_pcs *wp = container_of(pcs, struct mtk_sgmii_wrapper_pcs, pcs);
+
+	wp->lynxi_pcs->ops->pcs_get_state(wp->lynxi_pcs, state);
+
+	/* Continuously repeat re-configuration sequence until link comes up */
+	if (!state->link)
+		mtk_sgmii_wrapped_pcs_config(pcs, wp->neg_mode, state->interface,
+					     NULL, wp->permit_pause_to_mac);
+}
+
+static void mtk_sgmii_wrapped_pcs_an_restart(struct phylink_pcs *pcs)
+{
+	struct mtk_sgmii_wrapper_pcs *wp = container_of(pcs, struct mtk_sgmii_wrapper_pcs, pcs);
+
+	wp->lynxi_pcs->ops->pcs_an_restart(wp->lynxi_pcs);
+}
+
+static void mtk_sgmii_wrapped_pcs_link_up(struct phylink_pcs *pcs,
+					  unsigned int neg_mode,
+					  phy_interface_t interface, int speed,
+					  int duplex)
+{
+	struct mtk_sgmii_wrapper_pcs *wp = container_of(pcs, struct mtk_sgmii_wrapper_pcs, pcs);
+
+	wp->lynxi_pcs->ops->pcs_link_up(wp->lynxi_pcs, neg_mode, interface, speed, duplex);
+}
+
+static void mtk_sgmii_wrapped_pcs_disable(struct phylink_pcs *pcs)
+{
+	struct mtk_sgmii_wrapper_pcs *wp = container_of(pcs, struct mtk_sgmii_wrapper_pcs, pcs);
+
+	wp->lynxi_pcs->ops->pcs_disable(wp->lynxi_pcs);
+	wp->interface = PHY_INTERFACE_MODE_NA;
+	wp->neg_mode = -1;
+}
+
+static int mtk_sgmii_wrapped_pcs_enable(struct phylink_pcs *pcs)
+{
+	struct mtk_sgmii_wrapper_pcs *wp = container_of(pcs, struct mtk_sgmii_wrapper_pcs, pcs);
+
+	if (wp->lynxi_pcs->ops->pcs_enable)
+		wp->lynxi_pcs->ops->pcs_enable(wp->lynxi_pcs);
+
+	wp->interface = PHY_INTERFACE_MODE_NA;
+	wp->neg_mode = -1;
+
+	phy_power_on(wp->usxgmii_pcs->pextp);
+
+	return 0;
+}
+
+static const struct phylink_pcs_ops mtk_sgmii_wrapped_pcs_ops = {
+	.pcs_get_state = mtk_sgmii_wrapped_pcs_get_state,
+	.pcs_config = mtk_sgmii_wrapped_pcs_config,
+	.pcs_an_restart = mtk_sgmii_wrapped_pcs_an_restart,
+	.pcs_link_up = mtk_sgmii_wrapped_pcs_link_up,
+	.pcs_disable = mtk_sgmii_wrapped_pcs_disable,
+	.pcs_enable = mtk_sgmii_wrapped_pcs_enable,
+};
+
+static int mtk_sgmii_wrapper_init(struct mtk_usxgmii_pcs *mpcs)
+{
+	struct device_node *r = mpcs->dev->of_node, *np;
+	struct mtk_sgmii_wrapper_pcs *wp;
+	struct phylink_pcs *lynxi_pcs;
+	struct reset_control *rstc;
+	struct regmap *regmap;
+	struct clk *sgmii_sel, *sgmii_rx, *sgmii_tx;
+
+	np = of_parse_phandle(r, "mediatek,sgmiisys", 0);
+	if (!np)
+		return -ENODEV;
+
+	regmap = syscon_node_to_regmap(np);
+	of_node_put(np);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	rstc = of_reset_control_get_shared(r, "sgmii");
+
+	if (IS_ERR(rstc))
+		return PTR_ERR(rstc);
+
+	sgmii_sel = devm_clk_get_enabled(mpcs->dev, "sgmii_sel");
+	if (IS_ERR(sgmii_sel))
+		return PTR_ERR(sgmii_sel);
+
+	sgmii_rx = devm_clk_get_enabled(mpcs->dev, "sgmii_rx");
+	if (IS_ERR(sgmii_rx))
+		return PTR_ERR(sgmii_rx);
+
+	sgmii_tx = devm_clk_get_enabled(mpcs->dev, "sgmii_tx");
+	if (IS_ERR(sgmii_tx))
+		return PTR_ERR(sgmii_tx);
+
+	lynxi_pcs = mtk_pcs_lynxi_create(mpcs->dev, regmap, MTK_NETSYS_V3_AMA_RGC3, 0);
+
+	if (IS_ERR(lynxi_pcs))
+		return PTR_ERR(lynxi_pcs);
+
+	if (!lynxi_pcs)
+		return -ENODEV;
+
+	/* Make sure all PCS ops are supported by wrapped PCS */
+	if (!lynxi_pcs->ops->pcs_get_state ||
+	    !lynxi_pcs->ops->pcs_config ||
+	    !lynxi_pcs->ops->pcs_an_restart ||
+	    !lynxi_pcs->ops->pcs_link_up ||
+	    !lynxi_pcs->ops->pcs_disable)
+		return -EOPNOTSUPP;
+
+	wp = devm_kzalloc(mpcs->dev, sizeof(*wp), GFP_KERNEL);
+	if (!wp)
+		return -ENOMEM;
+
+	wp->pcs.neg_mode = lynxi_pcs->neg_mode;
+	wp->pcs.ops = &mtk_sgmii_wrapped_pcs_ops;
+	wp->pcs.poll = true;
+	wp->lynxi_pcs = lynxi_pcs;
+	wp->usxgmii_pcs = mpcs;
+	wp->clks[0] = sgmii_sel;
+	wp->clks[1] = sgmii_rx;
+	wp->clks[2] = sgmii_tx;
+	wp->reset = rstc;
+	wp->interface = PHY_INTERFACE_MODE_NA;
+	wp->neg_mode = -1;
+
+	if (IS_ERR(wp->reset))
+		return PTR_ERR(wp->reset);
+
+	reset_control_deassert(wp->reset);
+
+	mpcs->sgmii_pcs = &wp->pcs;
+
+	return 0;
+}
+
+static void mtk_sgmii_wrapper_destroy(struct mtk_usxgmii_pcs *mpcs)
+{
+	struct mtk_sgmii_wrapper_pcs *wp = container_of(mpcs->sgmii_pcs,
+							struct mtk_sgmii_wrapper_pcs,
+							pcs);
+
+	mtk_pcs_lynxi_destroy(wp->lynxi_pcs);
+	reset_control_put(wp->reset);
+}
+
+static int mtk_usxgmii_pcs_config(struct phylink_pcs *pcs, unsigned int neg_mode,
+				  phy_interface_t interface,
+				  const unsigned long *advertising,
+				  bool permit_pause_to_mac)
+{
+	struct mtk_usxgmii_pcs *mpcs = pcs_to_mtk_usxgmii_pcs(pcs);
+	unsigned int an_ctrl = 0, link_timer = 0, xfi_mode = 0, adapt_mode = 0;
+	bool mode_changed = false;
+
+	if (interface == PHY_INTERFACE_MODE_USXGMII) {
+		an_ctrl = FIELD_PREP(USXGMII_AN_SYNC_CNT, 0x1FF) | USXGMII_AN_ENABLE;
+		link_timer = FIELD_PREP(USXGMII_LINK_TIMER_IDLE_DETECT, 0x7B) |
+			     FIELD_PREP(USXGMII_LINK_TIMER_COMP_ACK_DETECT, 0x7B) |
+			     FIELD_PREP(USXGMII_LINK_TIMER_AN_RESTART, 0x7B);
+		xfi_mode = FIELD_PREP(USXGMII_XFI_RX_MODE, USXGMII_XFI_MODE_10G) |
+			   FIELD_PREP(USXGMII_XFI_TX_MODE, USXGMII_XFI_MODE_10G);
+	} else if (interface == PHY_INTERFACE_MODE_10GBASER) {
+		an_ctrl = FIELD_PREP(USXGMII_AN_SYNC_CNT, 0x1FF);
+		link_timer = FIELD_PREP(USXGMII_LINK_TIMER_IDLE_DETECT, 0x7B) |
+			     FIELD_PREP(USXGMII_LINK_TIMER_COMP_ACK_DETECT, 0x7B) |
+			     FIELD_PREP(USXGMII_LINK_TIMER_AN_RESTART, 0x7B);
+		xfi_mode = FIELD_PREP(USXGMII_XFI_RX_MODE, USXGMII_XFI_MODE_10G) |
+			   FIELD_PREP(USXGMII_XFI_TX_MODE, USXGMII_XFI_MODE_10G);
+		adapt_mode = USXGMII_RATE_UPDATE_MODE;
+	} else if (interface == PHY_INTERFACE_MODE_5GBASER) {
+		an_ctrl = FIELD_PREP(USXGMII_AN_SYNC_CNT, 0xFF);
+		link_timer = FIELD_PREP(USXGMII_LINK_TIMER_IDLE_DETECT, 0x3D) |
+			     FIELD_PREP(USXGMII_LINK_TIMER_COMP_ACK_DETECT, 0x3D) |
+			     FIELD_PREP(USXGMII_LINK_TIMER_AN_RESTART, 0x3D);
+		xfi_mode = FIELD_PREP(USXGMII_XFI_RX_MODE, USXGMII_XFI_MODE_5G) |
+			   FIELD_PREP(USXGMII_XFI_TX_MODE, USXGMII_XFI_MODE_5G);
+		adapt_mode = USXGMII_RATE_UPDATE_MODE;
+	} else {
+		return -EINVAL;
+	}
+
+	adapt_mode |= FIELD_PREP(USXGMII_RATE_ADAPT_MODE, USXGMII_RATE_ADAPT_MODE_X1);
+
+	if (mpcs->interface != interface) {
+		mpcs->interface = interface;
+		mode_changed = true;
+	}
+
+	phy_power_on(mpcs->pextp);
+	mtk_usxgmii_reset(mpcs);
+
+	/* Setup USXGMII AN ctrl */
+	mtk_m32(mpcs, RG_PCS_AN_CTRL0,
+		USXGMII_AN_SYNC_CNT | USXGMII_AN_ENABLE,
+		an_ctrl);
+
+	mtk_m32(mpcs, RG_PCS_AN_CTRL2,
+		USXGMII_LINK_TIMER_IDLE_DETECT |
+		USXGMII_LINK_TIMER_COMP_ACK_DETECT |
+		USXGMII_LINK_TIMER_AN_RESTART,
+		link_timer);
+
+	mpcs->neg_mode = neg_mode;
+
+	/* Gated MAC CK */
+	mtk_m32(mpcs, RG_PHY_TOP_SPEED_CTRL1,
+		USXGMII_MAC_CK_GATED, USXGMII_MAC_CK_GATED);
+
+	/* Enable interface force mode */
+	mtk_m32(mpcs, RG_PHY_TOP_SPEED_CTRL1,
+		USXGMII_IF_FORCE_EN, USXGMII_IF_FORCE_EN);
+
+	/* Setup USXGMII adapt mode */
+	mtk_m32(mpcs, RG_PHY_TOP_SPEED_CTRL1,
+		USXGMII_RATE_UPDATE_MODE | USXGMII_RATE_ADAPT_MODE,
+		adapt_mode);
+
+	/* Setup USXGMII speed */
+	mtk_m32(mpcs, RG_PHY_TOP_SPEED_CTRL1,
+		USXGMII_XFI_RX_MODE | USXGMII_XFI_TX_MODE,
+		xfi_mode);
+
+	usleep_range(1, 10);
+
+	/* Un-gated MAC CK */
+	mtk_m32(mpcs, RG_PHY_TOP_SPEED_CTRL1, USXGMII_MAC_CK_GATED, 0);
+
+	usleep_range(1, 10);
+
+	/* Disable interface force mode for the AN mode */
+	if (an_ctrl & USXGMII_AN_ENABLE)
+		mtk_m32(mpcs, RG_PHY_TOP_SPEED_CTRL1, USXGMII_IF_FORCE_EN, 0);
+
+	/* Setup PHY for interface mode */
+	phy_set_mode_ext(mpcs->pextp, PHY_MODE_ETHERNET, interface);
+
+	return mode_changed;
+}
+
+static void mtk_usxgmii_pcs_get_fixed_speed(struct mtk_usxgmii_pcs *mpcs,
+					    struct phylink_link_state *state)
+{
+	u32 val = mtk_r32(mpcs, RG_PHY_TOP_SPEED_CTRL1);
+	int speed;
+
+	/* Calculate speed from interface speed and rate adapt mode */
+	switch (FIELD_GET(USXGMII_XFI_RX_MODE, val)) {
+	case USXGMII_XFI_MODE_10G:
+		speed = 10000;
+		break;
+	case USXGMII_XFI_MODE_5G:
+		speed = 5000;
+		break;
+	case USXGMII_XFI_MODE_2P5G:
+		speed = 2500;
+		break;
+	default:
+		state->speed = SPEED_UNKNOWN;
+		return;
+	}
+
+	switch (FIELD_GET(USXGMII_RATE_ADAPT_MODE, val)) {
+	case USXGMII_RATE_ADAPT_MODE_X100:
+		speed /= 100;
+		break;
+	case USXGMII_RATE_ADAPT_MODE_X50:
+		speed /= 50;
+		break;
+	case USXGMII_RATE_ADAPT_MODE_X10:
+		speed /= 10;
+		break;
+	case USXGMII_RATE_ADAPT_MODE_X5:
+		speed /= 5;
+		break;
+	case USXGMII_RATE_ADAPT_MODE_X4:
+		speed /= 4;
+		break;
+	case USXGMII_RATE_ADAPT_MODE_X2:
+		speed /= 2;
+		break;
+	case USXGMII_RATE_ADAPT_MODE_X1:
+		break;
+	default:
+		state->speed = SPEED_UNKNOWN;
+		return;
+	}
+
+	state->speed = speed;
+	state->duplex = DUPLEX_FULL;
+}
+
+static void mtk_usxgmii_pcs_get_an_state(struct mtk_usxgmii_pcs *mpcs,
+					 struct phylink_link_state *state)
+{
+	u16 lpa;
+
+	/* Refresh LPA by toggling LPA_LATCH */
+	mtk_m32(mpcs, RG_PCS_AN_STS0, USXGMII_LPA_LATCH, USXGMII_LPA_LATCH);
+	ndelay(1020);
+	mtk_m32(mpcs, RG_PCS_AN_STS0, USXGMII_LPA_LATCH, 0);
+	ndelay(1020);
+	lpa = FIELD_GET(USXGMII_LPA, mtk_r32(mpcs, RG_PCS_AN_STS0));
+
+	phylink_decode_usxgmii_word(state, lpa);
+}
+
+static void mtk_usxgmii_pcs_get_state(struct phylink_pcs *pcs,
+				      struct phylink_link_state *state)
+{
+	struct mtk_usxgmii_pcs *mpcs = pcs_to_mtk_usxgmii_pcs(pcs);
+
+	/* Refresh USXGMII link status by toggling RG_PCS_AN_STATUS_UPDATE */
+	mtk_m32(mpcs, RG_PCS_RX_STATUS0, RG_PCS_RX_STATUS_UPDATE,
+		RG_PCS_RX_STATUS_UPDATE);
+	ndelay(1020);
+	mtk_m32(mpcs, RG_PCS_RX_STATUS0, RG_PCS_RX_STATUS_UPDATE, 0);
+	ndelay(1020);
+
+	/* Read USXGMII link status */
+	state->link = FIELD_GET(RG_PCS_RX_LINK_STATUS,
+				mtk_r32(mpcs, RG_PCS_RX_STATUS0));
+
+	/* Continuously repeat re-configuration sequence until link comes up */
+	if (!state->link) {
+		mtk_usxgmii_pcs_config(pcs, mpcs->neg_mode,
+				       state->interface, NULL, false);
+		return;
+	}
+
+	if (FIELD_GET(USXGMII_AN_ENABLE, mtk_r32(mpcs, RG_PCS_AN_CTRL0)))
+		mtk_usxgmii_pcs_get_an_state(mpcs, state);
+	else
+		mtk_usxgmii_pcs_get_fixed_speed(mpcs, state);
+}
+
+static void mtk_usxgmii_pcs_restart_an(struct phylink_pcs *pcs)
+{
+	struct mtk_usxgmii_pcs *mpcs = pcs_to_mtk_usxgmii_pcs(pcs);
+
+	mtk_m32(mpcs, RG_PCS_AN_CTRL0, USXGMII_AN_RESTART, USXGMII_AN_RESTART);
+}
+
+static void mtk_usxgmii_pcs_link_up(struct phylink_pcs *pcs, unsigned int neg_mode,
+				    phy_interface_t interface,
+				    int speed, int duplex)
+{
+	/* Reconfiguring USXGMII to ensure the quality of the RX signal
+	 * after the line side link up.
+	 */
+	mtk_usxgmii_pcs_config(pcs, neg_mode, interface, NULL, false);
+}
+
+static void mtk_usxgmii_pcs_disable(struct phylink_pcs *pcs)
+{
+	struct mtk_usxgmii_pcs *mpcs = pcs_to_mtk_usxgmii_pcs(pcs);
+
+	mpcs->interface = PHY_INTERFACE_MODE_NA;
+	mpcs->neg_mode = -1;
+}
+
+static const struct phylink_pcs_ops mtk_usxgmii_pcs_ops = {
+	.pcs_config = mtk_usxgmii_pcs_config,
+	.pcs_get_state = mtk_usxgmii_pcs_get_state,
+	.pcs_an_restart = mtk_usxgmii_pcs_restart_an,
+	.pcs_link_up = mtk_usxgmii_pcs_link_up,
+	.pcs_disable = mtk_usxgmii_pcs_disable,
+};
+
+static int mtk_usxgmii_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mtk_usxgmii_pcs *mpcs;
+	int ret;
+
+	mpcs = devm_kzalloc(dev, sizeof(*mpcs), GFP_KERNEL);
+	if (!mpcs)
+		return -ENOMEM;
+
+	mpcs->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(mpcs->base))
+		return PTR_ERR(mpcs->base);
+
+	mpcs->dev = dev;
+	mpcs->pcs.ops = &mtk_usxgmii_pcs_ops;
+	mpcs->pcs.poll = true;
+	mpcs->pcs.neg_mode = true;
+	mpcs->interface = PHY_INTERFACE_MODE_NA;
+	mpcs->neg_mode = -1;
+
+	mpcs->clk = devm_clk_get_enabled(mpcs->dev, "usxgmii");
+	if (IS_ERR(mpcs->clk))
+		return PTR_ERR(mpcs->clk);
+
+	mpcs->xfi_pll = devm_clk_get_enabled(mpcs->dev, "xfi_pll");
+	if (IS_ERR(mpcs->xfi_pll))
+		return PTR_ERR(mpcs->xfi_pll);
+
+	mpcs->reset = devm_reset_control_get_shared(dev, "xfi");
+	if (IS_ERR(mpcs->reset))
+		return PTR_ERR(mpcs->reset);
+
+	reset_control_deassert(mpcs->reset);
+
+	ret = mtk_xfi_pextp_init(mpcs);
+	if (ret)
+		return ret;
+
+	ret = mtk_sgmii_wrapper_init(mpcs);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, mpcs);
+
+	return 0;
+}
+
+static int mtk_usxgmii_remove(struct platform_device *pdev)
+{
+	struct mtk_usxgmii_pcs *mpcs = platform_get_drvdata(pdev);
+
+	mtk_sgmii_wrapper_destroy(mpcs);
+	phy_power_off(mpcs->pextp);
+
+	return 0;
+}
+
+static const struct of_device_id mtk_usxgmii_of_mtable[] = {
+	{ .compatible = "mediatek,mt7988-usxgmiisys" },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, mtk_usxgmii_of_mtable);
+
+struct phylink_pcs *mtk_usxgmii_select_pcs(struct device_node *np, phy_interface_t mode)
+{
+	struct platform_device *pdev;
+	struct mtk_usxgmii_pcs *mpcs;
+
+	if (!np)
+		return NULL;
+
+	if (!of_device_is_available(np))
+		return ERR_PTR(-ENODEV);
+
+	if (!of_match_node(mtk_usxgmii_of_mtable, np))
+		return ERR_PTR(-EINVAL);
+
+	pdev = of_find_device_by_node(np);
+	if (!pdev || !platform_get_drvdata(pdev)) {
+		if (pdev)
+			put_device(&pdev->dev);
+		return ERR_PTR(-EPROBE_DEFER);
+	}
+
+	mpcs = platform_get_drvdata(pdev);
+	put_device(&pdev->dev);
+
+	switch (mode) {
+	case PHY_INTERFACE_MODE_1000BASEX:
+	case PHY_INTERFACE_MODE_2500BASEX:
+	case PHY_INTERFACE_MODE_SGMII:
+		return mpcs->sgmii_pcs;
+	case PHY_INTERFACE_MODE_5GBASER:
+	case PHY_INTERFACE_MODE_10GBASER:
+	case PHY_INTERFACE_MODE_USXGMII:
+		return &mpcs->pcs;
+	default:
+		return NULL;
+	}
+}
+EXPORT_SYMBOL(mtk_usxgmii_select_pcs);
+
+static struct platform_driver mtk_usxgmii_driver = {
+	.driver = {
+		.name			= "mtk_usxgmii",
+		.suppress_bind_attrs	= true,
+		.of_match_table		= mtk_usxgmii_of_mtable,
+	},
+	.probe = mtk_usxgmii_probe,
+	.remove = mtk_usxgmii_remove,
+};
+module_platform_driver(mtk_usxgmii_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MediaTek USXGMII PCS driver");
+MODULE_AUTHOR("Daniel Golle <daniel@makrotopia.org>");
diff --git a/include/linux/pcs/pcs-mtk-usxgmii.h b/include/linux/pcs/pcs-mtk-usxgmii.h
new file mode 100644
index 0000000000000..7a3c49760ffa6
--- /dev/null
+++ b/include/linux/pcs/pcs-mtk-usxgmii.h
@@ -0,0 +1,18 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_PCS_MTK_USXGMII_H
+#define __LINUX_PCS_MTK_USXGMII_H
+
+#include <linux/phylink.h>
+
+/**
+ * mtk_usxgmii_select_pcs
+ * Return PCS indentified by a device node and the PHY interface mode in use
+ *
+ * @param np	Pointer to device node indentifying a MediaTek USXGMII PCS
+ * @param mode	Ethernet PHY interface mode
+ *
+ * @return	Pointer to phylink PCS instance of NULL
+ */
+struct phylink_pcs *mtk_usxgmii_select_pcs(struct device_node *np, phy_interface_t mode);
+
+#endif /* __LINUX_PCS_MTK_USXGMII_H */