[PATCH net-next v11 00/12] net: pcs: Introduce support for fwnode PCS

[PATCH net-next v11 00/12] net: pcs: Introduce support for fwnode PCS

[Christian Marangi]

This series introduce a most awaited feature that is correctly
provide PCS with fwnode without having to use specific export symbol
and additional handling of PCS in phylink.

At times there were 2 different implementation (this and the one
from Sean) but Sean agreed that this can be picked and used in favor
of his implementation as long as his case with race condition is
correctly handled.

---
First the PCS fwnode:

The concept is to implement a producer-consumer API similar to other
subsystem like clock or PHY.

That seems to be the best solution to the problem as PCS driver needs
to be detached from phylink and implement a simple way to provide a
PCS while maintaining support for probe defer or driver removal.

To keep the implementation simple, the PCS driver devs needs some
collaboration to correctly implement this. This is O.K. as helper
to correctly implement this are provided hence it's really a matter
of following a pattern to correct follow removal of a PCS driver.

A PCS provider have to implement and call fwnode_pcs_add_provider() in
probe function and define an xlate function to define how the PCS
should be provided based on the requested interface and phandle spec
defined in fwnode (based on the #pcs-cells)

fwnode_pcs_get() is provided to provide a specific PCS declared in
fwnode at index.

A simple xlate function is provided for simple single PCS
implementation, fwnode_pcs_simple_get.

A PCS provider on driver removal must call fwnode_pcs_del_provider()
to delete itself as a provider.

---
Second PCS handling in phylink:

We have the PCS problem for the only reason that in initial
implementation, we permitted way too much flexibility to MAC driver
and things started to deviate. At times we couldn't think SoC
would start to put PCS outside the MAC hence it was OK to assume
they would live in the same driver. With the introduction of
10g in more consumer devices, we are observing a rapid growth
of this pattern with multiple PCS external to MAC.

To put a stop on this, the only solution is to give back to phylink
control on PCS handling and enforce more robust supported interface
definition from both MAC and PCS side.

It's suggested to read patch 0003 of this series for more info, here
a brief explaination of the idea:

This series introduce handling of PCS in phylink and try to deprecate
.mac_select_pcs.

Phylink now might contain a linked list of available PCS and
those will be used for PCS selection on phylink_major_config.

MAC driver needs to define pcs_interfaces mask in phylink_config
for every interface that needs a dedicated PCS.

These PCS needs to be provided to phylink at phylink_create time
by setting the .fill_available_pcs and .num_possible_pcs in phylink_config.
Helpers to parse PCS from fwnode are provided
fwnode_phylink_pcs_count() that will return the count of PCS entries
described in the firmware node and fwnode_phylink_pcs_parse() that will
fill a preallocated array of PCS pointer with the actual available PCS
(ignoring the one that still needs to be probed).

phylink_create() will fill the internal PCS list with the passed
array of PCS. phylink_major_config and other user of .mac_select_pcs
are adapted to make use of this new PCS list.

The supported interface value is also moved internally to phylink
struct. This is to handle late removal and addition of PCS.
(the bonus effect to this is giving phylink a clear idea of what
is actually supported by the MAC and his constraint with PCS)

The supported interface mask in phylink is done by OR the
supported_interfaces in phylink_config with every PCS in PCS list.

PCS removal is supported by forcing a mac_config, refresh the
supported interfaces and run a phy_resolve().

PCS late addition is supported by introducing a global notifier
for PCS provider. If a phylink have the pcs_interfaces mask not
zero, it's registered to this notifier.

PCS provider will emit a global PCS add event to signal any
interface that a new PCS might be available.

The function will then check if the PCS is related to the MAC
fwnode and add it accordingly.

A user for this new implementation is provided as an Airoha PCS
driver. This was also tested downstream with the IPQ95xx QCOM SoC
and with the help of Daniel also on the various Mediatek MT7988
SoC with both SFP cage implementation and DSA attached.

Lots of tests were done with driver unbind/bind and with interface
up/down also by adding print to make sure major_config_fail gets
correctly triggered and reset once the PCS comes back.

The dedicated commits have longer description on the implementation
so it's suggested to also check there for additional info.

It's worth to mention that OpenWrt is currently using this on
Mediatek SoC and QCOM ipq807x/ipq60xx/ipq50xx and Airoha are
already ported in staging tree for testing.

---

Changes v11:
- Rework PCS release to notifier way (fix race as pointed out by bot)
- Add Ack from Lorenzo for Airoha Ethernet driver
- Introduce devm variant for pcs_provider_add
- Better support firmware node reference for PCS late attach
- Better protect list iteration with state mutex
- Minor fixup to airoha pcs driver (flow control fixup)
- Rebase on top of net-next
Changes v10:
- Minor code cleanup and fixes as suggested by bot
- Drop devlink patch
- Add reviewed by tag
- Configure old_link_state on PCS release
- Unlink PCS on error in phylink_create()
- Use list_add_tail
- Fix typo in Airoha PCS driver
- Update phylink migration guide
- Better handle late PCS attach (idempotent function and
  add unser state_mutex)
- Use dedicated lock in Airoha ethernet driver
Changes v9:
- Rebase on top of net-next/main
- Drop early verification of supported_interface
  (it can also be provided by get_capabilites MAC OP)
Changes v8:
- Back to RFC (net-next closed)
- Address additional bug reported by Sashiko bot
  - Better handle priv interface for Airoha PCS driver
  - Better handle locking for modifying the PCS list in
    phylink code
  - Improve fwnode_phylink_pcs_parse() parsing on -ENOENT
  - Better handle error condition in phylink_create()
  - Turn down the link when current PCS is released
- Fix compilation warning caused by copy paste error
Changes v7:
- Address all the bug from the Sashiko bot
- Rename .num_available_pcs to .num_possible_pcs
- Link PCS in phylink_create()
- Correctly unregister the notifier on phylink_destroy()
- Introduce fwnode_phylink_pcs_count()
- Better handle locking in phylink for PCS handling
- Better handle unavailable PCS at phylink_create() time
- Improve Documentation file
- Other minor fixes to address suggestion from bot
- Rebase on top of net-next
Changes v6:
- Rebase on top of net-next
- Add Documentation files
- Add fw_devlink patch
- Fix some comments typo
- Rework the airoha_eth.c implementation with new multi serdes code
- Extend PCS code with PCIe and USB support
- Align schema to new property
Changes v5:
- Rebase on top of net-next
- Use the new force_major_config
- Reword some comments and commit description
- Return -ENODEV instead of -EPROBE_DEFER to perevent race condition
- Drop phy_interface_copy patch (Russell pushed an equivalent version)
Changes v4:
- Move patch 0002 phy_interface_copy to 0002 (fix bisectability
  problem)
- Address review from Lorenzo for Airoha ethernet driver
- Fix kdoc error with missing Return (actually missing : before Return)
- Fix UNMET dependency reported error for CONFIG_FWNODE_PCS
- Revert to pcs.c instead of core.c (due to name conflict with other kmod)
- Fix clang compilation error for Airoha PCS driver
- Add missing inline function to pcs.h function
Changes v3:
- Out of RFC
- Fix various spelling mistake
- Drop circular dependency patch
- Complete Airoha Ethernet phylink integration
- Introduce .pcs_link_down PCS OP
Changes v2:
- Switch to fwnode
- Implement PCS provider notifier
- Better split changes
- Move supported_interfaces to phylink
- Add circular dependency patch
- Rework handling with indirect addition/removal and
  trigger of phylink_resolve()

Christian Marangi (12):
  net: phylink: keep and use MAC supported_interfaces in phylink struct
  net: phylink: introduce internal phylink PCS handling
  net: pcs: implement Firmware node support for PCS driver
  net: phylink: save phylink instance fwnode on phylink_create
  net: phylink: support PCS provider release
  net: phylink: support late PCS provider attach
  net: Document PCS subsystem
  MAINTAINERS: add myself as PCS subsystem maintainer
  net: phylink: add .pcs_link_down PCS OP
  dt-bindings: net: pcs: Document support for Airoha Ethernet PCS
  net: pcs: airoha: add PCS driver for Airoha AN7581 SoC
  net: airoha: add phylink support

 .../bindings/net/pcs/airoha,pcs.yaml          |  261 ++
 Documentation/networking/index.rst            |    1 +
 Documentation/networking/pcs.rst              |  229 ++
 Documentation/networking/sfp-phylink.rst      |   35 +-
 MAINTAINERS                                   |    9 +
 drivers/net/ethernet/airoha/Kconfig           |    2 +
 drivers/net/ethernet/airoha/airoha_eth.c      |  190 +-
 drivers/net/ethernet/airoha/airoha_eth.h      |    5 +
 drivers/net/ethernet/airoha/airoha_regs.h     |   12 +
 drivers/net/pcs/Kconfig                       |    8 +
 drivers/net/pcs/Makefile                      |    3 +
 drivers/net/pcs/airoha/Kconfig                |   12 +
 drivers/net/pcs/airoha/Makefile               |    7 +
 drivers/net/pcs/airoha/pcs-airoha-common.c    | 1303 ++++++++++
 drivers/net/pcs/airoha/pcs-airoha.h           | 1311 +++++++++++
 drivers/net/pcs/airoha/pcs-an7581.c           | 2093 +++++++++++++++++
 drivers/net/pcs/pcs.c                         |  294 +++
 drivers/net/phy/phylink.c                     |  347 ++-
 include/linux/pcs/pcs-provider.h              |   65 +
 include/linux/pcs/pcs.h                       |  141 ++
 include/linux/phylink.h                       |   28 +
 21 files changed, 6298 insertions(+), 58 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/net/pcs/airoha,pcs.yaml
 create mode 100644 Documentation/networking/pcs.rst
 create mode 100644 drivers/net/pcs/airoha/Kconfig
 create mode 100644 drivers/net/pcs/airoha/Makefile
 create mode 100644 drivers/net/pcs/airoha/pcs-airoha-common.c
 create mode 100644 drivers/net/pcs/airoha/pcs-airoha.h
 create mode 100644 drivers/net/pcs/airoha/pcs-an7581.c
 create mode 100644 drivers/net/pcs/pcs.c
 create mode 100644 include/linux/pcs/pcs-provider.h
 create mode 100644 include/linux/pcs/pcs.h

-- 
2.53.0

[PATCH net-next v11 01/12] net: phylink: keep and use MAC supported_interfaces in phylink struct

[Christian Marangi]

Add in phylink struct a copy of supported_interfaces from phylink_config
and make use of that instead of relying on phylink_config value.

This in preparation for support of PCS handling internally to phylink
where a PCS can be removed or added after the phylink is created and we
need both a reference of the supported_interfaces value from
phylink_config and an internal value that can be updated with the new
PCS info.

Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/phy/phylink.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index b241768edbcb..b7180ae76cc8 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -60,6 +60,11 @@ struct phylink {
 	/* The link configuration settings */
 	struct phylink_link_state link_config;
 
+	/* What interface are supported by the current link.
+	 * Can change on removal or addition of new PCS.
+	 */
+	DECLARE_PHY_INTERFACE_MASK(supported_interfaces);
+
 	/* The current settings */
 	phy_interface_t cur_interface;
 
@@ -628,7 +633,7 @@ static int phylink_validate_mask(struct phylink *pl, struct phy_device *phy,
 static int phylink_validate(struct phylink *pl, unsigned long *supported,
 			    struct phylink_link_state *state)
 {
-	const unsigned long *interfaces = pl->config->supported_interfaces;
+	const unsigned long *interfaces = pl->supported_interfaces;
 
 	if (state->interface == PHY_INTERFACE_MODE_NA)
 		return phylink_validate_mask(pl, NULL, supported, state,
@@ -1878,6 +1883,9 @@ struct phylink *phylink_create(struct phylink_config *config,
 		goto free_pl;
 	}
 
+	phy_interface_copy(pl->supported_interfaces,
+			   pl->config->supported_interfaces);
+
 	pl->mac_supports_eee_ops = phylink_mac_implements_lpi(mac_ops);
 	pl->mac_supports_eee = pl->mac_supports_eee_ops &&
 			       pl->config->lpi_capabilities &&
@@ -2024,7 +2032,7 @@ static int phylink_validate_phy(struct phylink *pl, struct phy_device *phy,
 		 * those which the host supports.
 		 */
 		phy_interface_and(interfaces, phy->possible_interfaces,
-				  pl->config->supported_interfaces);
+				  pl->supported_interfaces);
 
 		if (phy_interface_empty(interfaces)) {
 			phylink_err(pl, "PHY has no common interfaces\n");
@@ -2824,12 +2832,12 @@ static phy_interface_t phylink_sfp_select_interface(struct phylink *pl,
 		return interface;
 	}
 
-	if (!test_bit(interface, pl->config->supported_interfaces)) {
+	if (!test_bit(interface, pl->supported_interfaces)) {
 		phylink_err(pl,
 			    "selection of interface failed, SFP selected %s (%u) but MAC supports %*pbl\n",
 			    phy_modes(interface), interface,
 			    (int)PHY_INTERFACE_MODE_MAX,
-			    pl->config->supported_interfaces);
+			    pl->supported_interfaces);
 		return PHY_INTERFACE_MODE_NA;
 	}
 
@@ -3757,14 +3765,14 @@ static int phylink_sfp_config_optical(struct phylink *pl)
 
 	phylink_dbg(pl, "optical SFP: interfaces=[mac=%*pbl, sfp=%*pbl]\n",
 		    (int)PHY_INTERFACE_MODE_MAX,
-		    pl->config->supported_interfaces,
+		    pl->supported_interfaces,
 		    (int)PHY_INTERFACE_MODE_MAX,
 		    pl->sfp_interfaces);
 
 	/* Find the union of the supported interfaces by the PCS/MAC and
 	 * the SFP module.
 	 */
-	phy_interface_and(pl->sfp_interfaces, pl->config->supported_interfaces,
+	phy_interface_and(pl->sfp_interfaces, pl->supported_interfaces,
 			  pl->sfp_interfaces);
 	if (phy_interface_empty(pl->sfp_interfaces)) {
 		phylink_err(pl, "unsupported SFP module: no common interface modes\n");
@@ -3935,7 +3943,7 @@ static int phylink_sfp_connect_phy(void *upstream, struct phy_device *phy)
 
 	/* Set the PHY's host supported interfaces */
 	phy_interface_and(phy->host_interfaces, phylink_sfp_interfaces,
-			  pl->config->supported_interfaces);
+			  pl->supported_interfaces);
 
 	/* Do the initial configuration */
 	return phylink_sfp_config_phy(pl, phy);
-- 
2.53.0

[PATCH net-next v11 02/12] net: phylink: introduce internal phylink PCS handling

[Christian Marangi]

Introduce internal handling of PCS for phylink. This is an alternative
way to .mac_select_pcs that moves the selection logic of the PCS entirely
to phylink with the usage of the supported_interface value in the PCS
struct.

MAC should now provide a callback to fill the available PCS in
phylink_config in .fill_available_pcs and fill the .num_possible_pcs with
the number of elements in the array. MAC should also define a new bitmap,
pcs_interfaces, in phylink_config to define for what interface mode a
dedicated PCS is required.

On phylink_create(), an array of PCS pointer is allocated of size
.num_possible_pcs from phylink_config and .fill_available_pcs from
phylink_config is called passing as args the just allocated array and
the number of possible element in it.

MAC will fill this passed array with all the available PCS.

This array is then parsed and a linked list of PCS is created based on
the allocated PCS array filled by MAC via .fill_available_pcs().

Every PCS in phylink PCS list gets then linked to the phylink instance
by setting the phylink value in phylink_pcs struct to the phylink instance.
Also the supported_interface value in phylink struct is updated with
the new supported_interface from the provided PCS.

On phylink_destroy(), every PCS in phylink PCS list is unlinked from the
phylink instance by setting the phylink value in phylink_pcs struct to NULL
and removed from the PCS list.

phylink_validate_mac_and_pcs(), phylink_major_config() and
phylink_inband_caps() are updated to support this new implementation
with the PCS list stored in phylink.

They will make use of phylink_validate_pcs_interface() that will loop
for every PCS in the phylink PCS available list and find one that supports
the passed interface.

phylink_validate_pcs_interface() applies the same logic of .mac_select_pcs
where if a supported_interface value is not set for the PCS struct, then
it's assumed every interface is supported.

A MAC is required to implement either a .mac_select_pcs or make use of
the PCS list implementation. Implementing both will result in a fail
on phylink_create().

A MAC defining .num_possible_pcs in phylink_config MUST also define a
.fill_available_pcs or phylink_create() will fail with an negative error.

phylink value in phylink_pcs struct with this implementation is used to
track from PCS side when it's attached to a phylink instance. PCS driver
will make use of this information to correctly detach from a phylink
instance if needed.

phylink_pcs_change() is also changed to verify that the PCS that triggered
a link change is the one that is currently used by the phylink instance.

The .mac_select_pcs implementation is not changed but it's expected that
every MAC driver migrates to the new implementation to later deprecate
and remove .mac_select_pcs.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/phy/phylink.c | 205 +++++++++++++++++++++++++++++++++-----
 include/linux/phylink.h   |  16 +++
 2 files changed, 196 insertions(+), 25 deletions(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index b7180ae76cc8..9decd7333c70 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -60,6 +60,9 @@ struct phylink {
 	/* The link configuration settings */
 	struct phylink_link_state link_config;
 
+	/* List of available PCS */
+	struct list_head pcs_list;
+
 	/* What interface are supported by the current link.
 	 * Can change on removal or addition of new PCS.
 	 */
@@ -154,6 +157,8 @@ static const phy_interface_t phylink_sfp_interface_preference[] = {
 
 static DECLARE_PHY_INTERFACE_MASK(phylink_sfp_interfaces);
 
+static void phylink_run_resolve(struct phylink *pl);
+
 /**
  * phylink_set_port_modes() - set the port type modes in the ethtool mask
  * @mask: ethtool link mode mask
@@ -517,12 +522,29 @@ static void phylink_validate_mask_caps(unsigned long *supported,
 	linkmode_and(state->advertising, state->advertising, mask);
 }
 
+static int phylink_validate_pcs_interface(struct phylink_pcs *pcs,
+					  phy_interface_t interface)
+{
+	/* If PCS define an empty supported_interfaces value, assume
+	 * all interface are supported.
+	 */
+	if (phy_interface_empty(pcs->supported_interfaces))
+		return 0;
+
+	/* Ensure that this PCS supports the interface mode */
+	if (!test_bit(interface, pcs->supported_interfaces))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int phylink_validate_mac_and_pcs(struct phylink *pl,
 					unsigned long *supported,
 					struct phylink_link_state *state)
 {
-	struct phylink_pcs *pcs = NULL;
 	unsigned long capabilities;
+	struct phylink_pcs *pcs;
+	bool pcs_found = false;
 	int ret;
 
 	/* Get the PCS for this interface mode */
@@ -530,9 +552,24 @@ static int phylink_validate_mac_and_pcs(struct phylink *pl,
 		pcs = pl->mac_ops->mac_select_pcs(pl->config, state->interface);
 		if (IS_ERR(pcs))
 			return PTR_ERR(pcs);
+
+		pcs_found = !!pcs;
+	/*
+	 * Find a PCS in available PCS list for the requested interface.
+	 *
+	 * Skip searching if the MAC doesn't require a dedicated PCS for
+	 * the requested interface.
+	 */
+	} else if (test_bit(state->interface, pl->config->pcs_interfaces)) {
+		list_for_each_entry(pcs, &pl->pcs_list, list) {
+			if (!phylink_validate_pcs_interface(pcs, state->interface)) {
+				pcs_found = true;
+				break;
+			}
+		}
 	}
 
-	if (pcs) {
+	if (pcs_found) {
 		/* The PCS, if present, must be setup before phylink_create()
 		 * has been called. If the ops is not initialised, print an
 		 * error and backtrace rather than oopsing the kernel.
@@ -544,13 +581,10 @@ static int phylink_validate_mac_and_pcs(struct phylink *pl,
 			return -EINVAL;
 		}
 
-		/* Ensure that this PCS supports the interface which the MAC
-		 * returned it for. It is an error for the MAC to return a PCS
-		 * that does not support the interface mode.
-		 */
-		if (!phy_interface_empty(pcs->supported_interfaces) &&
-		    !test_bit(state->interface, pcs->supported_interfaces)) {
-			phylink_err(pl, "MAC returned PCS which does not support %s\n",
+		/* Recheck PCS to handle legacy way for .mac_select_pcs */
+		ret = phylink_validate_pcs_interface(pcs, state->interface);
+		if (ret) {
+			phylink_err(pl, "selected PCS does not support %s\n",
 				    phy_modes(state->interface));
 			return -EINVAL;
 		}
@@ -964,12 +998,22 @@ static unsigned int phylink_inband_caps(struct phylink *pl,
 					 phy_interface_t interface)
 {
 	struct phylink_pcs *pcs;
+	bool pcs_found = false;
 
-	if (!pl->mac_ops->mac_select_pcs)
-		return 0;
+	if (pl->mac_ops->mac_select_pcs) {
+		pcs = pl->mac_ops->mac_select_pcs(pl->config,
+						  interface);
+		pcs_found = !!pcs;
+	} else if (test_bit(interface, pl->config->pcs_interfaces)) {
+		list_for_each_entry(pcs, &pl->pcs_list, list) {
+			if (!phylink_validate_pcs_interface(pcs, interface)) {
+				pcs_found = true;
+				break;
+			}
+		}
+	}
 
-	pcs = pl->mac_ops->mac_select_pcs(pl->config, interface);
-	if (!pcs)
+	if (!pcs_found)
 		return 0;
 
 	return phylink_pcs_inband_caps(pcs, interface);
@@ -1264,10 +1308,36 @@ static void phylink_major_config(struct phylink *pl, bool restart,
 			pl->major_config_failed = true;
 			return;
 		}
+	/* Find a PCS in available PCS list for the requested interface.
+	 * This doesn't overwrite the previous .mac_select_pcs as either
+	 * .mac_select_pcs or PCS list implementation are permitted.
+	 *
+	 * Skip searching if the MAC doesn't require a dedicated PCS for
+	 * the requested interface.
+	 */
+	} else if (test_bit(state->interface, pl->config->pcs_interfaces)) {
+		bool pcs_found = false;
+
+		list_for_each_entry(pcs, &pl->pcs_list, list) {
+			if (!phylink_validate_pcs_interface(pcs,
+							    state->interface)) {
+				pcs_found = true;
+				break;
+			}
+		}
 
-		pcs_changed = pl->pcs != pcs;
+		if (!pcs_found) {
+			phylink_err(pl,
+				    "couldn't find a PCS for %s\n",
+				    phy_modes(state->interface));
+
+			pl->major_config_failed = true;
+			return;
+		}
 	}
 
+	pcs_changed = pl->pcs != pcs;
+
 	phylink_pcs_neg_mode(pl, pcs, state->interface, state->advertising);
 
 	phylink_dbg(pl, "major config, active %s/%s/%s\n",
@@ -1294,13 +1364,15 @@ static void phylink_major_config(struct phylink *pl, bool restart,
 	if (pcs_changed) {
 		phylink_pcs_disable(pl->pcs);
 
-		if (pl->pcs)
-			pl->pcs->phylink = NULL;
+		if (pl->mac_ops->mac_select_pcs) {
+			if (pl->pcs)
+				pl->pcs->phylink = NULL;
 
-		if (pcs)
-			pcs->phylink = pl;
+			if (pcs)
+				pcs->phylink = pl;
+		}
 
-		pl->pcs = pcs;
+		WRITE_ONCE(pl->pcs, pcs);
 	}
 
 	if (pl->pcs)
@@ -1833,6 +1905,44 @@ int phylink_set_fixed_link(struct phylink *pl,
 }
 EXPORT_SYMBOL_GPL(phylink_set_fixed_link);
 
+static int phylink_fill_available_pcs(struct phylink *pl,
+				      struct phylink_config *config)
+{
+	struct phylink_pcs **pcss;
+	int i, ret;
+
+	if (!config->num_possible_pcs)
+		return 0;
+
+	if (!config->fill_available_pcs) {
+		dev_err(config->dev,
+			"phylink: error: num_possible_pcs defined but no fill_available_pcs\n");
+		return -EINVAL;
+	}
+
+	pcss = kzalloc_objs(*pcss, config->num_possible_pcs);
+	if (!pcss)
+		return -ENOMEM;
+
+	ret = config->fill_available_pcs(config, pcss, config->num_possible_pcs);
+	if (ret < 0)
+		goto out;
+
+	for (i = 0; i < config->num_possible_pcs; i++) {
+		struct phylink_pcs *pcs = pcss[i];
+
+		if (!pcs)
+			continue;
+
+		list_add_tail(&pcs->list, &pl->pcs_list);
+	}
+
+out:
+	kfree(pcss);
+
+	return ret;
+}
+
 /**
  * phylink_create() - create a phylink instance
  * @config: a pointer to the target &struct phylink_config
@@ -1854,13 +1964,17 @@ struct phylink *phylink_create(struct phylink_config *config,
 			       phy_interface_t iface,
 			       const struct phylink_mac_ops *mac_ops)
 {
+	struct phylink_pcs *tmp, *pcs;
 	struct phylink *pl;
 	int ret;
 
-	/* Validate the supplied configuration */
-	if (phy_interface_empty(config->supported_interfaces)) {
+	/*
+	 * Make sure either PCS internal validation or .mac_select_pcs
+	 * is used. Return error if both are defined.
+	 */
+	if (config->num_possible_pcs && mac_ops->mac_select_pcs) {
 		dev_err(config->dev,
-			"phylink: error: empty supported_interfaces\n");
+			"phylink: error: either phylink_config .num_possible_pcs or .mac_select_pcs must be used\n");
 		return ERR_PTR(-EINVAL);
 	}
 
@@ -1871,6 +1985,7 @@ struct phylink *phylink_create(struct phylink_config *config,
 	mutex_init(&pl->phydev_mutex);
 	mutex_init(&pl->state_mutex);
 	INIT_WORK(&pl->resolve, phylink_resolve);
+	INIT_LIST_HEAD(&pl->pcs_list);
 
 	pl->config = config;
 	if (config->type == PHYLINK_NETDEV) {
@@ -1883,9 +1998,24 @@ struct phylink *phylink_create(struct phylink_config *config,
 		goto free_pl;
 	}
 
+	/* Fill the PCS list with available PCS from phylink config */
+	ret = phylink_fill_available_pcs(pl, config);
+	if (ret < 0)
+		goto free_pl;
+
+	/* Link available PCS to phylink */
+	list_for_each_entry(pcs, &pl->pcs_list, list)
+		pcs->phylink = pl;
+
 	phy_interface_copy(pl->supported_interfaces,
 			   pl->config->supported_interfaces);
 
+	/* Update supported interfaces */
+	list_for_each_entry(pcs, &pl->pcs_list, list)
+		phy_interface_or(pl->supported_interfaces,
+				 pl->supported_interfaces,
+				 pcs->supported_interfaces);
+
 	pl->mac_supports_eee_ops = phylink_mac_implements_lpi(mac_ops);
 	pl->mac_supports_eee = pl->mac_supports_eee_ops &&
 			       pl->config->lpi_capabilities &&
@@ -1917,7 +2047,7 @@ struct phylink *phylink_create(struct phylink_config *config,
 
 	ret = phylink_parse_mode(pl, fwnode);
 	if (ret < 0)
-		goto free_pl;
+		goto unlink_pcs_list;
 
 	if (pl->cfg_link_an_mode == MLO_AN_FIXED) {
 		ret = phylink_parse_fixedlink(pl, fwnode);
@@ -1936,6 +2066,11 @@ struct phylink *phylink_create(struct phylink_config *config,
 release_link_gpio:
 	if (pl->link_gpio)
 		gpiod_put(pl->link_gpio);
+unlink_pcs_list:
+	list_for_each_entry_safe(pcs, tmp, &pl->pcs_list, list) {
+		list_del(&pcs->list);
+		pcs->phylink = NULL;
+	}
 free_pl:
 	kfree(pl);
 	return ERR_PTR(ret);
@@ -1953,11 +2088,24 @@ EXPORT_SYMBOL_GPL(phylink_create);
  */
 void phylink_destroy(struct phylink *pl)
 {
+	struct phylink_pcs *pcs, *tmp;
+
 	sfp_bus_del_upstream(pl->sfp_bus);
 	if (pl->link_gpio)
 		gpiod_put(pl->link_gpio);
 
 	cancel_work_sync(&pl->resolve);
+
+	mutex_lock(&pl->state_mutex);
+
+	/* Remove every PCS from phylink PCS list */
+	list_for_each_entry_safe(pcs, tmp, &pl->pcs_list, list) {
+		pcs->phylink = NULL;
+		list_del(&pcs->list);
+	}
+
+	mutex_unlock(&pl->state_mutex);
+
 	kfree(pl);
 }
 EXPORT_SYMBOL_GPL(phylink_destroy);
@@ -2409,8 +2557,15 @@ void phylink_pcs_change(struct phylink_pcs *pcs, bool up)
 {
 	struct phylink *pl = pcs->phylink;
 
-	if (pl)
-		phylink_link_changed(pl, up, "pcs");
+	/*
+	 * Ignore PCS link state change if the PCS is not
+	 * attached to a phylink instance or the phylink
+	 * instance is not currently using this PCS.
+	 */
+	if (!pl || READ_ONCE(pl->pcs) != pcs)
+		return;
+
+	phylink_link_changed(pl, up, "pcs");
 }
 EXPORT_SYMBOL_GPL(phylink_pcs_change);
 
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index 2bc0db3d52ac..ca9dfc142388 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -12,6 +12,7 @@ struct ethtool_cmd;
 struct fwnode_handle;
 struct net_device;
 struct phylink;
+struct phylink_pcs;
 
 enum {
 	MLO_PAUSE_NONE,
@@ -151,6 +152,8 @@ enum phylink_op_type {
  *		     if MAC link is at %MLO_AN_FIXED mode.
  * @supported_interfaces: bitmap describing which PHY_INTERFACE_MODE_xxx
  *                        are supported by the MAC/PCS.
+ * @pcs_interfaces: bitmap describing for which PHY_INTERFACE_MODE_xxx a
+ *		    dedicated PCS is required.
  * @lpi_interfaces: bitmap describing which PHY interface modes can support
  *		    LPI signalling.
  * @mac_capabilities: MAC pause/speed/duplex capabilities.
@@ -160,6 +163,10 @@ enum phylink_op_type {
  * @wol_phy_legacy: Use Wake-on-Lan with PHY even if phy_can_wakeup() is false
  * @wol_phy_speed_ctrl: Use phy speed control on suspend/resume
  * @wol_mac_support: Bitmask of MAC supported %WAKE_* options
+ * @num_possible_pcs: num of possible phylink_pcs PCS
+ * @fill_available_pcs: callback to fill the available PCS in the passed
+ *			array struct of phylink_pcs PCS available_pcs up to
+ *			num_possible_pcs.
  */
 struct phylink_config {
 	struct device *dev;
@@ -172,6 +179,7 @@ struct phylink_config {
 	void (*get_fixed_state)(struct phylink_config *config,
 				struct phylink_link_state *state);
 	DECLARE_PHY_INTERFACE_MASK(supported_interfaces);
+	DECLARE_PHY_INTERFACE_MASK(pcs_interfaces);
 	DECLARE_PHY_INTERFACE_MASK(lpi_interfaces);
 	unsigned long mac_capabilities;
 	unsigned long lpi_capabilities;
@@ -182,6 +190,11 @@ struct phylink_config {
 	bool wol_phy_legacy;
 	bool wol_phy_speed_ctrl;
 	u32 wol_mac_support;
+
+	unsigned int num_possible_pcs;
+	int (*fill_available_pcs)(struct phylink_config *config,
+				  struct phylink_pcs **available_pcs,
+				  unsigned int num_possible_pcs);
 };
 
 void phylink_limit_mac_speed(struct phylink_config *config, u32 max_speed);
@@ -497,6 +510,9 @@ struct phylink_pcs {
 	struct phylink *phylink;
 	bool poll;
 	bool rxc_always_on;
+
+	/* private: */
+	struct list_head list;
 };
 
 /**
-- 
2.53.0

[PATCH net-next v11 03/12] net: pcs: implement Firmware node support for PCS driver

[Christian Marangi]

Implement the foundation of Firmware node support for PCS driver.

To support this, implement a simple Provider API where a PCS driver can
expose multiple PCS with an xlate .get function.

PCS driver will have to call fwnode_pcs_add_provider() and pass the
firmware node pointer and a xlate function to return the correct PCS for
the passed #pcs-cells.

This will register the PCS in a global list of providers so that
consumer can access it.

The consumer will then use fwnode_pcs_get() to get the actual PCS by
passing the firmware node pointer and the index for #pcs-cells.

For a simple implementation where #pcs-cells is 0 and the PCS driver
expose a single PCS, the xlate function fwnode_pcs_simple_get() is
provided.

For an advanced implementation a custom xlate function is required.

On removal the PCS driver must delete itself from the provider list
using fwnode_pcs_del_provider().

A devm variant devm_fwnode_pcs_add() is provided to automate the release
procedure.

Generic functions fwnode_phylink_pcs_count() and fwnode_phylink_pcs_parse()
are provided for MAC driver that will declare PCS in DT (or ACPI).

Function fwnode_phylink_pcs_count() will parse "pcs-handle" property and
will return the number of PCS entries described in the passed firmware
node.

Function fwnode_phylink_pcs_parse() will parse "pcs-handle" property and
fill the passed available_pcs array with the available PCS found up to
passed num_pcs value. It's worth to mention that this function will ignore
PCS that still needs to be probed (returning -ENODEV) and such PCS won't be
added to the available_pcs array.

Co-developed-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/pcs/Kconfig          |   6 +
 drivers/net/pcs/Makefile         |   1 +
 drivers/net/pcs/pcs.c            | 240 +++++++++++++++++++++++++++++++
 include/linux/pcs/pcs-provider.h |  65 +++++++++
 include/linux/pcs/pcs.h          |  75 ++++++++++
 5 files changed, 387 insertions(+)
 create mode 100644 drivers/net/pcs/pcs.c
 create mode 100644 include/linux/pcs/pcs-provider.h
 create mode 100644 include/linux/pcs/pcs.h

diff --git a/drivers/net/pcs/Kconfig b/drivers/net/pcs/Kconfig
index e417fd66f660..2ce89d4bff6b 100644
--- a/drivers/net/pcs/Kconfig
+++ b/drivers/net/pcs/Kconfig
@@ -5,6 +5,12 @@
 
 menu "PCS device drivers"
 
+config FWNODE_PCS
+	bool "PCS Firmware Node"
+	depends on (ACPI || OF)
+	help
+		Firmware node PCS accessors
+
 config PCS_XPCS
 	tristate "Synopsys DesignWare Ethernet XPCS"
 	select PHYLINK
diff --git a/drivers/net/pcs/Makefile b/drivers/net/pcs/Makefile
index 4f7920618b90..3005cdd89ab7 100644
--- a/drivers/net/pcs/Makefile
+++ b/drivers/net/pcs/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 # Makefile for Linux PCS drivers
 
+obj-$(CONFIG_FWNODE_PCS)	+= pcs.o
 pcs_xpcs-$(CONFIG_PCS_XPCS)	:= pcs-xpcs.o pcs-xpcs-plat.o \
 				   pcs-xpcs-nxp.o pcs-xpcs-wx.o
 
diff --git a/drivers/net/pcs/pcs.c b/drivers/net/pcs/pcs.c
new file mode 100644
index 000000000000..7f6d9941c1e3
--- /dev/null
+++ b/drivers/net/pcs/pcs.c
@@ -0,0 +1,240 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/mutex.h>
+#include <linux/property.h>
+#include <linux/phylink.h>
+#include <linux/pcs/pcs.h>
+#include <linux/pcs/pcs-provider.h>
+
+MODULE_DESCRIPTION("PCS library");
+MODULE_AUTHOR("Christian Marangi <ansuelsmth@gmail.com>");
+MODULE_LICENSE("GPL");
+
+struct fwnode_pcs_provider {
+	struct list_head link;
+
+	struct fwnode_handle *fwnode;
+	struct phylink_pcs *(*get)(struct fwnode_reference_args *pcsspec,
+				   void *data);
+
+	void *data;
+};
+
+static LIST_HEAD(fwnode_pcs_providers);
+static DEFINE_MUTEX(fwnode_pcs_mutex);
+
+struct phylink_pcs *fwnode_pcs_simple_get(struct fwnode_reference_args *pcsspec,
+					  void *data)
+{
+	return data;
+}
+EXPORT_SYMBOL_GPL(fwnode_pcs_simple_get);
+
+struct fwnode_pcs_provider *
+fwnode_pcs_add_provider(struct fwnode_handle *fwnode,
+			struct phylink_pcs *(*get)(struct fwnode_reference_args *pcsspec,
+						   void *data),
+			void *data)
+{
+	struct fwnode_pcs_provider *pp;
+
+	if (!fwnode)
+		return 0;
+
+	pp = kzalloc_obj(*pp);
+	if (!pp)
+		return ERR_PTR(-ENOMEM);
+
+	pp->fwnode = fwnode_handle_get(fwnode);
+	pp->data = data;
+	pp->get = get;
+
+	mutex_lock(&fwnode_pcs_mutex);
+	list_add(&pp->link, &fwnode_pcs_providers);
+	mutex_unlock(&fwnode_pcs_mutex);
+	pr_debug("Added pcs provider from %pfwf\n", fwnode);
+
+	fwnode_dev_initialized(fwnode, true);
+
+	return pp;
+}
+EXPORT_SYMBOL_GPL(fwnode_pcs_add_provider);
+
+void fwnode_pcs_del_provider(struct fwnode_pcs_provider *pp)
+{
+	if (IS_ERR_OR_NULL(pp))
+		return;
+
+	mutex_lock(&fwnode_pcs_mutex);
+
+	list_del(&pp->link);
+	fwnode_dev_initialized(pp->fwnode, false);
+	fwnode_handle_put(pp->fwnode);
+	kfree(pp);
+
+	mutex_unlock(&fwnode_pcs_mutex);
+}
+EXPORT_SYMBOL_GPL(fwnode_pcs_del_provider);
+
+static void devm_fwnode_pcs_del(struct device *dev, void *res)
+{
+	struct fwnode_pcs_provider *pp = *(struct fwnode_pcs_provider **)res;
+
+	fwnode_pcs_del_provider(pp);
+}
+
+struct fwnode_pcs_provider *
+devm_fwnode_pcs_add_provider(struct device *dev, struct fwnode_handle *fwnode,
+			     struct phylink_pcs *(*get)(struct fwnode_reference_args *pcsspec,
+							void *data),
+			     void *data)
+{
+	struct fwnode_pcs_provider **ptr, *pp;
+
+	ptr = devres_alloc(devm_fwnode_pcs_del, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	pp = fwnode_pcs_add_provider(fwnode, get, data);
+
+	if (!IS_ERR(pp)) {
+		*ptr = pp;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return pp;
+}
+EXPORT_SYMBOL_GPL(devm_fwnode_pcs_add_provider);
+
+static int fwnode_parse_pcsspec(const struct fwnode_handle *fwnode,
+				int index, const char *name,
+				struct fwnode_reference_args *out_args)
+{
+	int ret;
+
+	if (!fwnode)
+		return -EINVAL;
+
+	if (name) {
+		index = fwnode_property_match_string(fwnode, "pcs-names",
+						     name);
+		if (index < 0)
+			return index;
+	}
+
+	ret = fwnode_property_get_reference_args(fwnode, "pcs-handle",
+						 "#pcs-cells", 0, index,
+						 out_args);
+	if (ret || (name && index < 0))
+		return ret;
+
+	return 0;
+}
+
+static struct phylink_pcs *
+fwnode_pcs_get_from_pcsspec(struct fwnode_reference_args *pcsspec)
+{
+	struct fwnode_pcs_provider *provider;
+	struct phylink_pcs *pcs = ERR_PTR(-ENODEV);
+
+	if (!pcsspec)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&fwnode_pcs_mutex);
+	list_for_each_entry(provider, &fwnode_pcs_providers, link) {
+		if (provider->fwnode == pcsspec->fwnode) {
+			pcs = provider->get(pcsspec, provider->data);
+			if (!IS_ERR(pcs))
+				break;
+		}
+	}
+	mutex_unlock(&fwnode_pcs_mutex);
+
+	return pcs;
+}
+
+static struct phylink_pcs *__fwnode_pcs_get(const struct fwnode_handle *fwnode,
+					    unsigned int index, const char *con_id)
+{
+	struct fwnode_reference_args pcsspec;
+	struct phylink_pcs *pcs;
+	int ret;
+
+	ret = fwnode_parse_pcsspec(fwnode, index, con_id, &pcsspec);
+	if (ret)
+		return ERR_PTR(ret);
+
+	pcs = fwnode_pcs_get_from_pcsspec(&pcsspec);
+	fwnode_handle_put(pcsspec.fwnode);
+
+	return pcs;
+}
+
+struct phylink_pcs *fwnode_pcs_get(const struct fwnode_handle *fwnode, unsigned int index)
+{
+	return __fwnode_pcs_get(fwnode, index, NULL);
+}
+EXPORT_SYMBOL_GPL(fwnode_pcs_get);
+
+unsigned int fwnode_phylink_pcs_count(struct fwnode_handle *fwnode)
+{
+	struct fwnode_reference_args out_args;
+	int index = 0;
+	int ret;
+
+	while (true) {
+		ret = fwnode_property_get_reference_args(fwnode, "pcs-handle",
+							 "#pcs-cells", 0, index,
+							 &out_args);
+		/* We expect to reach an -ENOENT error while counting */
+		if (ret)
+			break;
+
+		fwnode_handle_put(out_args.fwnode);
+		index++;
+	}
+
+	return index;
+}
+EXPORT_SYMBOL_GPL(fwnode_phylink_pcs_count);
+
+int fwnode_phylink_pcs_parse(struct fwnode_handle *fwnode,
+			     struct phylink_pcs **available_pcs,
+			     unsigned int num_pcs)
+{
+	unsigned int i, found = 0;
+
+	if (!available_pcs)
+		return -EINVAL;
+
+	if (!fwnode_property_present(fwnode, "pcs-handle"))
+		return -ENODEV;
+
+	for (i = 0; i < num_pcs; i++) {
+		struct phylink_pcs *pcs;
+
+		pcs = fwnode_pcs_get(fwnode, i);
+		if (IS_ERR(pcs)) {
+			/* Exit early if no PCS remain.*/
+			if (PTR_ERR(pcs) == -ENOENT)
+				break;
+
+			/*
+			 * Ignore -ENODEV error for PCS that still
+			 * needs to probe.
+			 */
+			if (PTR_ERR(pcs) == -ENODEV)
+				continue;
+
+			return PTR_ERR(pcs);
+		}
+
+		available_pcs[found] = pcs;
+		found++;
+	}
+
+	return found;
+}
+EXPORT_SYMBOL_GPL(fwnode_phylink_pcs_parse);
diff --git a/include/linux/pcs/pcs-provider.h b/include/linux/pcs/pcs-provider.h
new file mode 100644
index 000000000000..5df48022bc6e
--- /dev/null
+++ b/include/linux/pcs/pcs-provider.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __LINUX_PCS_PROVIDER_H
+#define __LINUX_PCS_PROVIDER_H
+
+struct fwnode_pcs_provider;
+
+/**
+ * fwnode_pcs_simple_get - Simple xlate function to retrieve PCS
+ * @pcsspec: reference arguments
+ * @data: Context data (assumed assigned to the single PCS)
+ *
+ * Returns: the PCS pointed by data.
+ */
+struct phylink_pcs *fwnode_pcs_simple_get(struct fwnode_reference_args *pcsspec,
+					  void *data);
+
+/**
+ * fwnode_pcs_add_provider - Registers a new PCS provider
+ * @fwnode: Firmware node
+ * @get: xlate function to retrieve the PCS
+ * @data: Context data
+ *
+ * Register and add a new PCS provider to the global providers list
+ * for the firmware node. The relevant PCS from the PCS provider
+ * is retrieved from the passed xlate function.
+ *
+ * Returns: A pointer to the registered PCS provider on success, or
+ * an ERR_PTR() encoded error code on failure.
+ */
+struct fwnode_pcs_provider *
+fwnode_pcs_add_provider(struct fwnode_handle *fwnode,
+			struct phylink_pcs *(*get)(struct fwnode_reference_args *pcsspec,
+						   void *data),
+			void *data);
+
+/**
+ * fwnode_pcs_del_provider - Removes a PCS provider
+ * @fwnode: Firmware node
+ */
+void fwnode_pcs_del_provider(struct fwnode_pcs_provider *pp);
+
+/**
+ * fwnode_pcs_add_provider - Registers a new PCS provider
+ * @dev: Device of the PCS provider
+ * @fwnode: Firmware node
+ * @get: xlate function to retrieve the PCS
+ * @data: Context data
+ *
+ * Register and add a new PCS provider to the global providers list
+ * for the firmware node. The relevant PCS from the PCS provider
+ * is retrieved from the passed xlate function. While at that, it
+ * also associates the device with the PCS provider using devres.
+ * On driver detach, release function is invoked on the devres data,
+ * then, devres data is freed.
+ *
+ * Returns: A pointer to the registered PCS provider on success, or
+ * an ERR_PTR() encoded error code on failure.
+ */
+struct fwnode_pcs_provider *
+devm_fwnode_pcs_add_provider(struct device *dev, struct fwnode_handle *fwnode,
+			     struct phylink_pcs *(*get)(struct fwnode_reference_args *pcsspec,
+							void *data),
+			     void *data);
+
+#endif /* __LINUX_PCS_PROVIDER_H */
diff --git a/include/linux/pcs/pcs.h b/include/linux/pcs/pcs.h
new file mode 100644
index 000000000000..08132f3f70f4
--- /dev/null
+++ b/include/linux/pcs/pcs.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __LINUX_PCS_H
+#define __LINUX_PCS_H
+
+#include <linux/phylink.h>
+
+#if IS_ENABLED(CONFIG_FWNODE_PCS)
+/**
+ * fwnode_pcs_get - Retrieves a PCS from a firmware node
+ * @fwnode: firmware node
+ * @index: index fwnode PCS handle in firmware node
+ *
+ * Get a PCS from the firmware node at index.
+ *
+ * Returns: a pointer to the phylink_pcs or a negative
+ * error pointer. Can return -ENODEV if the PCS is not
+ * present in global providers list (either due to driver
+ * still needs to be probed or it failed to probe/removed).
+ */
+struct phylink_pcs *fwnode_pcs_get(const struct fwnode_handle *fwnode,
+				   unsigned int index);
+
+/**
+ * fwnode_phylink_pcs_count - count PCS entries described in firmware node
+ * @fwnode: firmware node
+ *
+ * Helper function to count the number of PCS entries referenced by the
+ * "pcs-handle" property in a firmware node.
+ *
+ * Note that this function counts all PCS references in the firmware node,
+ * regardless of whether the corresponding PCS devices are already probed.
+ *
+ * Returns: number of PCS entries described in the firmware node.
+ */
+unsigned int fwnode_phylink_pcs_count(struct fwnode_handle *fwnode);
+
+/**
+ * fwnode_phylink_pcs_parse - parse available PCS from firmware node
+ * @fwnode: firmware node
+ * @available_pcs: pointer to preallocated array of PCS
+ * @num_pcs: maximum number of PCS entries to scan
+ *
+ * Helper function that parses PCS references from the "pcs-handle"
+ * property of a firmware node and fills @available_pcs with PCS that are
+ * currently available up to @num_pcs.
+ *
+ * Only PCS that are currently available are stored in @available_pcs.
+ * PCS that returns -ENODEV are skipped.
+ *
+ * Returns: number of PCS stored in @available_pcs, or negative error code.
+ */
+int fwnode_phylink_pcs_parse(struct fwnode_handle *fwnode,
+			     struct phylink_pcs **available_pcs,
+			     unsigned int num_pcs);
+#else
+static inline struct phylink_pcs *fwnode_pcs_get(const struct fwnode_handle *fwnode,
+						 unsigned int index)
+{
+	return ERR_PTR(-ENOENT);
+}
+
+static inline unsigned int fwnode_phylink_pcs_count(struct fwnode_handle *fwnode)
+{
+	return 0;
+}
+
+static inline int fwnode_phylink_pcs_parse(struct fwnode_handle *fwnode,
+					   struct phylink_pcs **available_pcs,
+					   unsigned int num_pcs)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
+#endif /* __LINUX_PCS_H */
-- 
2.53.0

[PATCH net-next v11 04/12] net: phylink: save phylink instance fwnode on phylink_create

[Christian Marangi]

The firmware node associated with the phylink instance might differ from
the device firmware node passed in phylink_config as such device can
reference the parent switch or other platform peripherals.

Some function might need to reference this firmware node after
phylink_create so add a dedicated fwnode entry in phylink internal struct
and save it on phylink_create().

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/phy/phylink.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 9decd7333c70..041405ce6bf0 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -44,6 +44,7 @@ struct phylink {
 	const struct phylink_mac_ops *mac_ops;
 	struct phylink_config *config;
 	struct phylink_pcs *pcs;
+	const struct fwnode_handle *fwnode;
 	struct device *dev;
 	unsigned int old_link_state:1;
 
@@ -1988,6 +1989,7 @@ struct phylink *phylink_create(struct phylink_config *config,
 	INIT_LIST_HEAD(&pl->pcs_list);
 
 	pl->config = config;
+	pl->fwnode = fwnode;
 	if (config->type == PHYLINK_NETDEV) {
 		pl->netdev = to_net_dev(config->dev);
 		netif_carrier_off(pl->netdev);
-- 
2.53.0

[PATCH net-next v11 05/12] net: phylink: support PCS provider release

[Christian Marangi]

Add support for release of fwnode PCS from a PCS provider.
This works by creating a global notifier for the PCS provider and
making each phylink instance that makes use of fwnode subscribe to
this notifier.

The PCS notifier will emit the event FWNODE_PCS_PROVIDER_DEL every time
a new PCS provider is released.

phylink will then react to this event and will call the new function
fwnode_phylink_pcs_get_from_fwnode() that will check if the PCS fwnode
provided by the event is present in the pcs-handle property of the
phylink instance.

If a related PCS is found, then such PCS is removed from the phylink
instance PCS list and the supported_interfaces value is updated.

The flag force_major_config is set to make phylink resolve reconfigure
the interface (even if it didn't change).
This is needed to handle the special case when the current PCS used
by phylink is removed and a major_config is needed to propagae the
configuration change. With this option enabled we also force mac_config
even if the PHY link is not up for the in-band case.

Finally a phylink resolve is triggered to handle the PCS removal.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/pcs/pcs.c     | 50 ++++++++++++++++++++++++
 drivers/net/phy/phylink.c | 82 ++++++++++++++++++++++++++++++++++++++-
 include/linux/pcs/pcs.h   | 65 +++++++++++++++++++++++++++++++
 3 files changed, 196 insertions(+), 1 deletion(-)

diff --git a/drivers/net/pcs/pcs.c b/drivers/net/pcs/pcs.c
index 7f6d9941c1e3..f575fbed896d 100644
--- a/drivers/net/pcs/pcs.c
+++ b/drivers/net/pcs/pcs.c
@@ -22,6 +22,19 @@ struct fwnode_pcs_provider {
 
 static LIST_HEAD(fwnode_pcs_providers);
 static DEFINE_MUTEX(fwnode_pcs_mutex);
+static BLOCKING_NOTIFIER_HEAD(fwnode_pcs_notify_list);
+
+int register_fwnode_pcs_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&fwnode_pcs_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(register_fwnode_pcs_notifier);
+
+int unregister_fwnode_pcs_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&fwnode_pcs_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_fwnode_pcs_notifier);
 
 struct phylink_pcs *fwnode_pcs_simple_get(struct fwnode_reference_args *pcsspec,
 					  void *data)
@@ -67,6 +80,11 @@ void fwnode_pcs_del_provider(struct fwnode_pcs_provider *pp)
 
 	mutex_lock(&fwnode_pcs_mutex);
 
+	/* Signal phylink to release any PCS from this provider */
+	blocking_notifier_call_chain(&fwnode_pcs_notify_list,
+				     FWNODE_PCS_PROVIDER_DEL,
+				     pp->fwnode);
+
 	list_del(&pp->link);
 	fwnode_dev_initialized(pp->fwnode, false);
 	fwnode_handle_put(pp->fwnode);
@@ -178,6 +196,38 @@ struct phylink_pcs *fwnode_pcs_get(const struct fwnode_handle *fwnode, unsigned
 }
 EXPORT_SYMBOL_GPL(fwnode_pcs_get);
 
+struct phylink_pcs *
+fwnode_phylink_pcs_get_from_fwnode(const struct fwnode_handle *fwnode,
+				   struct fwnode_handle *pcs_fwnode)
+{
+	struct fwnode_reference_args pcsspec;
+	int index = 0;
+	int ret;
+
+	/* Loop until we find a matching PCS node or
+	 * fwnode_parse_pcsspec() returns error
+	 * if we don't have any other PCS reference to check.
+	 */
+	while (true) {
+		ret = fwnode_parse_pcsspec(fwnode, index, NULL, &pcsspec);
+		if (ret)
+			return ERR_PTR(ret);
+
+		/* Exit loop if we found the matching PCS node */
+		if (pcsspec.fwnode == pcs_fwnode) {
+			fwnode_handle_put(pcsspec.fwnode);
+			break;
+		}
+
+		/* Check the next PCS reference */
+		fwnode_handle_put(pcsspec.fwnode);
+		index++;
+	}
+
+	return fwnode_pcs_get(fwnode, index);
+}
+EXPORT_SYMBOL_GPL(fwnode_phylink_pcs_get_from_fwnode);
+
 unsigned int fwnode_phylink_pcs_count(struct fwnode_handle *fwnode)
 {
 	struct fwnode_reference_args out_args;
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 041405ce6bf0..548e783ae2aa 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -12,6 +12,7 @@
 #include <linux/netdevice.h>
 #include <linux/of.h>
 #include <linux/of_mdio.h>
+#include <linux/pcs/pcs.h>
 #include <linux/phy.h>
 #include <linux/phy_fixed.h>
 #include <linux/phylink.h>
@@ -63,6 +64,7 @@ struct phylink {
 
 	/* List of available PCS */
 	struct list_head pcs_list;
+	struct notifier_block fwnode_pcs_nb;
 
 	/* What interface are supported by the current link.
 	 * Can change on removal or addition of new PCS.
@@ -1929,6 +1931,8 @@ static int phylink_fill_available_pcs(struct phylink *pl,
 	if (ret < 0)
 		goto out;
 
+	mutex_lock(&pl->state_mutex);
+
 	for (i = 0; i < config->num_possible_pcs; i++) {
 		struct phylink_pcs *pcs = pcss[i];
 
@@ -1938,12 +1942,72 @@ static int phylink_fill_available_pcs(struct phylink *pl,
 		list_add_tail(&pcs->list, &pl->pcs_list);
 	}
 
+	mutex_unlock(&pl->state_mutex);
+
 out:
 	kfree(pcss);
 
 	return ret;
 }
 
+static void phylink_del_pcs(struct phylink *pl, struct phylink_pcs *pcs)
+{
+	list_del(&pcs->list);
+	pcs->phylink = NULL;
+
+	/*
+	 * Check if we are removing the PCS currently
+	 * in use by this phylink instance. If this is the case,
+	 * tear down the link, force phylink resolve to reconfigure the
+	 * interface mode, disable the current PCS and set the
+	 * phylink PCS to NULL.
+	 */
+	if (pl->pcs == pcs) {
+		if (pl->old_link_state) {
+			phylink_link_down(pl);
+			pl->old_link_state = false;
+		}
+		if (pl->cfg_link_an_mode == MLO_AN_INBAND)
+			timer_delete_sync(&pl->link_poll);
+		phylink_pcs_disable(pl->pcs);
+
+		pl->force_major_config = true;
+		WRITE_ONCE(pl->pcs, NULL);
+	}
+}
+
+static int pcs_provider_notify(struct notifier_block *self,
+			       unsigned long val, void *data)
+{
+	struct phylink *pl = container_of(self, struct phylink, fwnode_pcs_nb);
+	const struct fwnode_handle *pl_fwnode = pl->fwnode;
+	struct fwnode_handle *pcs_fwnode = data;
+	struct phylink_pcs *pcs;
+
+	/* Check if the PCS provider is relevant for this phylink instance */
+	pcs = fwnode_phylink_pcs_get_from_fwnode(pl_fwnode, pcs_fwnode);
+	if (IS_ERR(pcs))
+		return NOTIFY_DONE;
+
+	mutex_lock(&pl->state_mutex);
+
+	phylink_del_pcs(pl, pcs);
+
+	/* Refresh supported interfaces */
+	phy_interface_copy(pl->supported_interfaces,
+			   pl->config->supported_interfaces);
+	list_for_each_entry(pcs, &pl->pcs_list, list)
+		phy_interface_or(pl->supported_interfaces,
+				 pl->supported_interfaces,
+				 pcs->supported_interfaces);
+
+	mutex_unlock(&pl->state_mutex);
+
+	phylink_run_resolve(pl);
+
+	return NOTIFY_OK;
+}
+
 /**
  * phylink_create() - create a phylink instance
  * @config: a pointer to the target &struct phylink_config
@@ -2000,10 +2064,18 @@ struct phylink *phylink_create(struct phylink_config *config,
 		goto free_pl;
 	}
 
+	/* First register notifier for hotplug PCS events */
+	if (!phy_interface_empty(config->pcs_interfaces)) {
+		pl->fwnode_pcs_nb.notifier_call = pcs_provider_notify;
+		register_fwnode_pcs_notifier(&pl->fwnode_pcs_nb);
+	}
+
 	/* Fill the PCS list with available PCS from phylink config */
 	ret = phylink_fill_available_pcs(pl, config);
 	if (ret < 0)
-		goto free_pl;
+		goto unregister_pcs_notify;
+
+	mutex_lock(&pl->state_mutex);
 
 	/* Link available PCS to phylink */
 	list_for_each_entry(pcs, &pl->pcs_list, list)
@@ -2018,6 +2090,8 @@ struct phylink *phylink_create(struct phylink_config *config,
 				 pl->supported_interfaces,
 				 pcs->supported_interfaces);
 
+	mutex_unlock(&pl->state_mutex);
+
 	pl->mac_supports_eee_ops = phylink_mac_implements_lpi(mac_ops);
 	pl->mac_supports_eee = pl->mac_supports_eee_ops &&
 			       pl->config->lpi_capabilities &&
@@ -2073,6 +2147,8 @@ struct phylink *phylink_create(struct phylink_config *config,
 		list_del(&pcs->list);
 		pcs->phylink = NULL;
 	}
+unregister_pcs_notify:
+	unregister_fwnode_pcs_notifier(&pl->fwnode_pcs_nb);
 free_pl:
 	kfree(pl);
 	return ERR_PTR(ret);
@@ -2096,6 +2172,10 @@ void phylink_destroy(struct phylink *pl)
 	if (pl->link_gpio)
 		gpiod_put(pl->link_gpio);
 
+	/* Unregister notifier for late PCS attach */
+	if (pl->fwnode_pcs_nb.notifier_call)
+		unregister_fwnode_pcs_notifier(&pl->fwnode_pcs_nb);
+
 	cancel_work_sync(&pl->resolve);
 
 	mutex_lock(&pl->state_mutex);
diff --git a/include/linux/pcs/pcs.h b/include/linux/pcs/pcs.h
index 08132f3f70f4..f9dcbf58d053 100644
--- a/include/linux/pcs/pcs.h
+++ b/include/linux/pcs/pcs.h
@@ -4,7 +4,36 @@
 
 #include <linux/phylink.h>
 
+enum fwnode_pcs_notify_event {
+	FWNODE_PCS_PROVIDER_DEL,
+};
+
 #if IS_ENABLED(CONFIG_FWNODE_PCS)
+/**
+ * register_fwnode_pcs_notifier - Register a notifier block for fwnode
+ *				  PCS events
+ * @nb: pointer to the notifier block
+ *
+ * Registers a notifier block to the fwnode_pcs_notify_list blocking
+ * notifier chain. This allows phylink instance to subscribe for
+ * PCS provider events.
+ *
+ * Returns: 0 or a negative error.
+ */
+int register_fwnode_pcs_notifier(struct notifier_block *nb);
+
+/**
+ * unregister_fwnode_pcs_notifier - Unregister a notifier block for fwnode
+ *				    PCS events
+ * @nb: pointer to the notifier block
+ *
+ * Unregisters a notifier block to the fwnode_pcs_notify_list blocking
+ * notifier chain.
+ *
+ * Returns: 0 or a negative error.
+ */
+int unregister_fwnode_pcs_notifier(struct notifier_block *nb);
+
 /**
  * fwnode_pcs_get - Retrieves a PCS from a firmware node
  * @fwnode: firmware node
@@ -20,6 +49,25 @@
 struct phylink_pcs *fwnode_pcs_get(const struct fwnode_handle *fwnode,
 				   unsigned int index);
 
+/**
+ * fwnode_phylink_pcs_get_from_fwnode - Retrieves the PCS provided
+ *					by the firmware node from a
+ *					firmware node
+ * @fwnode: firmware node
+ * @pcs_fwnode: PCS firmware node
+ *
+ * Parse 'pcs-handle' in 'fwnode' and get the PCS that match
+ * 'pcs_fwnode' firmware node.
+ *
+ * Returns: a pointer to the phylink_pcs or a negative
+ * error pointer. Can return -EPROBE_DEFER if the PCS is not
+ * present in global providers list (either due to driver
+ * still needs to be probed or it failed to probe/removed)
+ */
+struct phylink_pcs *
+fwnode_phylink_pcs_get_from_fwnode(const struct fwnode_handle *fwnode,
+				   struct fwnode_handle *pcs_fwnode);
+
 /**
  * fwnode_phylink_pcs_count - count PCS entries described in firmware node
  * @fwnode: firmware node
@@ -53,12 +101,29 @@ int fwnode_phylink_pcs_parse(struct fwnode_handle *fwnode,
 			     struct phylink_pcs **available_pcs,
 			     unsigned int num_pcs);
 #else
+static inline int register_fwnode_pcs_notifier(struct notifier_block *nb)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int unregister_fwnode_pcs_notifier(struct notifier_block *nb)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline struct phylink_pcs *fwnode_pcs_get(const struct fwnode_handle *fwnode,
 						 unsigned int index)
 {
 	return ERR_PTR(-ENOENT);
 }
 
+static inline struct phylink_pcs *
+fwnode_phylink_pcs_get_from_fwnode(const struct fwnode_handle *fwnode,
+				   struct fwnode_handle *pcs_fwnode)
+{
+	return ERR_PTR(-ENOENT);
+}
+
 static inline unsigned int fwnode_phylink_pcs_count(struct fwnode_handle *fwnode)
 {
 	return 0;
-- 
2.53.0

[PATCH net-next v11 06/12] net: phylink: support late PCS provider attach

[Christian Marangi]

Add support for late PCS provider attachment to a phylink instance.
Similar to FWNODE_PCS_PROVIDER_DEL, FWNODE_PCS_PROVIDER_ADD is added to
address the case where a PCS provider is added after a phylink instance is
created and started.

The PCS notifier will emit the event FWNODE_PCS_PROVIDER_ADD every time
a new PCS provider is added.

If a related PCS is found, then such PCS is added to the phylink
instance PCS list.

Then we link the PCS to the phylink instance and we refresh the supported
interfaces of the phylink instance.

Finally we check if we are in a major_config_failed scenario and trigger
an interface reconfiguration in the next phylink resolve.

In the example scenario where the link was previously torn down due to
removal of PCS, the link will be established again as the PCS came back
and is now available to phylink.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/pcs/pcs.c     |  4 ++++
 drivers/net/phy/phylink.c | 41 +++++++++++++++++++++++++++++++++------
 include/linux/pcs/pcs.h   |  1 +
 3 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/drivers/net/pcs/pcs.c b/drivers/net/pcs/pcs.c
index f575fbed896d..79fa596c2900 100644
--- a/drivers/net/pcs/pcs.c
+++ b/drivers/net/pcs/pcs.c
@@ -69,6 +69,10 @@ fwnode_pcs_add_provider(struct fwnode_handle *fwnode,
 
 	fwnode_dev_initialized(fwnode, true);
 
+	blocking_notifier_call_chain(&fwnode_pcs_notify_list,
+				     FWNODE_PCS_PROVIDER_ADD,
+				     fwnode);
+
 	return pp;
 }
 EXPORT_SYMBOL_GPL(fwnode_pcs_add_provider);
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 548e783ae2aa..69d4f6675db0 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -1908,6 +1908,27 @@ int phylink_set_fixed_link(struct phylink *pl,
 }
 EXPORT_SYMBOL_GPL(phylink_set_fixed_link);
 
+static void phylink_add_pcs(struct phylink *pl, struct phylink_pcs *pcs)
+{
+	struct phylink_pcs *tmp;
+
+	/*
+	 * Make sure state mutex is locked to protect concurrent
+	 * access to phylink instance PCS list from
+	 * initial fill_available_pcs and late PCS attach
+	 */
+	lockdep_assert_held(&pl->state_mutex);
+
+	list_for_each_entry(tmp, &pl->pcs_list, list)
+		if (tmp == pcs)
+			return;
+
+	list_add_tail(&pcs->list, &pl->pcs_list);
+
+	/* Link PCS to phylink */
+	pcs->phylink = pl;
+}
+
 static int phylink_fill_available_pcs(struct phylink *pl,
 				      struct phylink_config *config)
 {
@@ -1939,7 +1960,7 @@ static int phylink_fill_available_pcs(struct phylink *pl,
 		if (!pcs)
 			continue;
 
-		list_add_tail(&pcs->list, &pl->pcs_list);
+		phylink_add_pcs(pl, pcs);
 	}
 
 	mutex_unlock(&pl->state_mutex);
@@ -1991,7 +2012,19 @@ static int pcs_provider_notify(struct notifier_block *self,
 
 	mutex_lock(&pl->state_mutex);
 
-	phylink_del_pcs(pl, pcs);
+	switch (val) {
+	case FWNODE_PCS_PROVIDER_ADD:
+		phylink_add_pcs(pl, pcs);
+
+		/* Force an interface reconfig if major config fail */
+		if (pl->major_config_failed)
+			pl->force_major_config = true;
+
+		break;
+	case FWNODE_PCS_PROVIDER_DEL:
+		phylink_del_pcs(pl, pcs);
+		break;
+	}
 
 	/* Refresh supported interfaces */
 	phy_interface_copy(pl->supported_interfaces,
@@ -2077,10 +2110,6 @@ struct phylink *phylink_create(struct phylink_config *config,
 
 	mutex_lock(&pl->state_mutex);
 
-	/* Link available PCS to phylink */
-	list_for_each_entry(pcs, &pl->pcs_list, list)
-		pcs->phylink = pl;
-
 	phy_interface_copy(pl->supported_interfaces,
 			   pl->config->supported_interfaces);
 
diff --git a/include/linux/pcs/pcs.h b/include/linux/pcs/pcs.h
index f9dcbf58d053..5cdd121b12f7 100644
--- a/include/linux/pcs/pcs.h
+++ b/include/linux/pcs/pcs.h
@@ -5,6 +5,7 @@
 #include <linux/phylink.h>
 
 enum fwnode_pcs_notify_event {
+	FWNODE_PCS_PROVIDER_ADD,
 	FWNODE_PCS_PROVIDER_DEL,
 };
 
-- 
2.53.0

[PATCH net-next v11 07/12] net: Document PCS subsystem

[Christian Marangi]

Add extensive documentation of the new PCS subsystem and the fwnode
implementation with producer/consumer API.

Also update the sfp-phylink migration guide.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 Documentation/networking/index.rst       |   1 +
 Documentation/networking/pcs.rst         | 229 +++++++++++++++++++++++
 Documentation/networking/sfp-phylink.rst |  35 ++--
 3 files changed, 241 insertions(+), 24 deletions(-)
 create mode 100644 Documentation/networking/pcs.rst

diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst
index 44a422ad3b05..3fce8f6ac089 100644
--- a/Documentation/networking/index.rst
+++ b/Documentation/networking/index.rst
@@ -28,6 +28,7 @@ Contents:
    net_failover
    page_pool
    phy
+   pcs
    sfp-phylink
    alias
    bridge
diff --git a/Documentation/networking/pcs.rst b/Documentation/networking/pcs.rst
new file mode 100644
index 000000000000..144adaedee37
--- /dev/null
+++ b/Documentation/networking/pcs.rst
@@ -0,0 +1,229 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============
+PCS Subsystem
+=============
+
+The PCS (Physical Coding Sublayer) subsystem handles the registration and lookup
+of PCS devices. These devices contain the upper sublayers of the Ethernet
+physical layer, generally handling framing, scrambling, and encoding tasks. PCS
+devices may also include PMA (Physical Medium Attachment) components. PCS
+devices transfer data between the Link-layer MAC device, and the rest of the
+physical layer, typically via a serdes. The output of the serdes may be
+connected more-or-less directly to the medium when using fiber-optic or
+backplane connections (1000BASE-SX, 1000BASE-KX, etc). It may also communicate
+with a separate PHY (such as over SGMII) which handles the connection to the
+medium (such as 1000BASE-T).
+
+Remark on usage of .mac_select_pcs and fw_node PCS
+--------------------------------------------------
+
+There are generally two ways to look up a PCS device.
+
+1. MAC OP struct .mac_select_pcs (considered deprecated)
+2. Internal PCS handling with ``num_possible_pcs`` and ``fill_available_pcs``
+
+Implementation 1 leaves the entire handling of the PCS to the MAC
+driver with the selection of the PCS driven by .mac_select_pcs.
+Custom implementations are required if the PCS is external to the MAC
+and needs to be handled by a separate driver.
+
+Implementation 2 makes the phylink core code to select the PCS
+provided by ``num_possible_pcs`` and ``fill_available_pcs`` either
+via internal MAC handling or firmware node (fwnode)
+
+Implementation 1 is considered deprecated and it's suggested to
+switch to implementation 2 and where possible switch to firmware
+node design.
+
+.. _pcs_fwnode:
+
+Looking up PCS Devices (fwnode implementation)
+-----------------------------------------------
+
+The lookup of a PCS device follows the common producer/consumer implementation
+used by similar subsystems with a ``#pcs-cells`` on the producer and a
+``pcs-handle`` property on the consumer::
+
+    pcs: pcs {
+        // ...
+        #pcs-cells = <0>;
+    };
+
+    ethernet-controller {
+        // ...
+        pcs-handle = <&pcs>;
+    };
+
+On :c:func:`phylink_create`, phylink will use the ``num_possible_pcs``
+value and ``fill_available_pcs`` helper function in
+:c:struct:`phylink_config` to compose the list of available PCS that can be
+used for the phylink instance.
+
+Phylink will then internally handle the selection of the correct PCS for
+the requested interface mode based on the interface modes configured in
+``pcs_interfaces`` in :c:struct:`phylink_config` struct and
+``supported_interfaces`` in :c:struct:`phylink_pcs` struct.
+
+A PCS is considered eligible when the requested interface mode is present
+in both ``pcs_interfaces`` in :c:struct:`phylink_config` struct and
+``supported_interfaces`` in :c:struct:`phylink_pcs` struct.
+
+``supported_interfaces`` describes all interface modes supported by the MAC,
+whereas ``pcs_interfaces`` identifies the subset that require PCS selection.
+
+For the special implementation where the PCS is internal or part of the MAC
+and a dedicated driver is not needed, it's possible to leave the implementation
+of the PCS to the MAC driver and just implement the ``num_possible_pcs``
+value and ``fill_available_pcs`` helper  function in
+:c:struct:`phylink_config` referencing the local :c:struct:`phylink_pcs`
+struct allocated from the MAC driver.
+
+.. _pcs_consumer:
+
+Using PCS Devices
+-----------------
+
+It's mandatory to either implement the ``mac_select_pcs`` callback
+of :c:struct:`phylink_mac_ops` or ``num_possible_pcs`` and ``fill_available_pcs``
+of :c:struct:`phylink_config` to use a PCS for a MAC.
+
+The fwnode implementation exposes simple helpers to parse the PCS from
+the fwnode :c:func:`fwnode_phylink_pcs_count` and
+:c:func:`fwnode_phylink_pcs_parse`. The :c:func:`fwnode_phylink_pcs_count` helper
+takes the fwnode where the ``pcs-handle`` should be parsed and return the
+number of PCS entries described in the fwnode.
+The :c:func:`fwnode_phylink_pcs_parse` helper takes three arguments,
+the fwnode where the ``pcs-handle`` should be parsed, an allocated array
+of :c:struct:`phylink_pcs` pointer where to put the parsed PCS from the fwnode
+and the maximum number of PCS to parse.
+Contrary to :c:func:`fwnode_phylink_pcs_count`, :c:func:`fwnode_phylink_pcs_parse`
+helper fills the allocated array with ONLY the available PCS and return the
+number of available PCS found. PCS that returns -ENODEV will be skipped and
+won't be inserted in the allocated array.
+
+A phylink instance may use multiple PCS devices. The maximum number is reported
+through ``num_possible_pcs``.
+
+It's mandatory to specify for what interface a PCS is needed. This can be done
+by filling the ``pcs_interfaces`` in :c:struct:`phylink_config` struct.
+If the requested interface mode is not present in this bitmask, phylink does
+not search for a PCS for  that specific mode. (example MAC doesn't need a PCS
+for SGMII but require one for USXGMII)
+
+With the use of the :c:func:`fwnode_phylink_pcs_parse` a common implementation
+is the following::
+
+   static int mac_fill_available_pcs(struct phylink_config *config,
+   				                      struct phylink_pcs **available_pcs,
+					                      unsigned int num_possible_pcs)
+   {
+   	struct device *dev = config->dev;
+
+   	return fwnode_phylink_pcs_parse(dev_fwnode(dev), available_pcs,
+						                    num_possible_pcs);
+   }
+
+   static int mac_setup_phylink(struct net_device *netdev)
+   {
+      struct phylink_config *config;
+
+      // ...
+
+      config->dev = &netdev->dev;
+
+      // ...
+
+      // Parse possible PCS and fill num_possible_pcs.
+      config->num_possible_pcs = fwnode_phylink_pcs_count(dev_fwnode(&netdev->dev));
+      config->fill_available_pcs = mac_fill_available_pcs;
+
+      __set_bit(PHY_INTERFACE_MODE_INTERNAL, config->supported_interfaces);
+      __set_bit(PHY_INTERFACE_MODE_SGMII, config->supported_interfaces);
+      __set_bit(PHY_INTERFACE_MODE_1000BASEX, config->supported_interfaces);
+      __set_bit(PHY_INTERFACE_MODE_USXGMII, config->supported_interfaces);
+
+      // PCS required only for USXGMII
+      __set_bit(PHY_INTERFACE_MODE_USXGMII, config->pcs_interfaces);
+
+      phylink = phylink_create(config, //...
+
+It's worth to mention that it's phylink code that takes care of allocating
+the array of :c:struct:`phylink_pcs` pointer for ``fill_available_pcs``
+callback based on the value set in ``num_possible_pcs`` for
+:c:struct:`phylink_config` struct.
+
+The ``fill_available_pcs`` callback must not write more than
+``num_possible_pcs`` entries. The third argument may be used to validate
+that there is enough space to fill all the available PCS in the passed array
+of :c:struct:`phylink_pcs` pointer.
+
+The ``fill_available_pcs`` callback is called only on :c:func:`phylink_create`
+and is used only to compose the initial available PCS list. Ownership of PCS
+is held by phylink.
+
+.. _pcs_producer:
+
+Writing PCS Drivers
+-------------------
+
+To write a PCS driver, first implement :c:struct:`phylink_pcs_ops`. Then,
+register your PCS in your probe function using :c:func:`fwnode_pcs_add_provider`.
+The :c:func:`fwnode_pcs_add_provider` takes three arguments, the fwnode where
+the PCS provider should be registered to, a get function to return the requested
+PCS based on ``#pcs-cells`` and a pointer to reference private data for the get
+function.
+
+The PCS will then be registered to a global list of PCS provider that the
+PCS fwnode implementation will use to parse it.
+
+For the simple case where the PCS driver expose a single PCS,
+:c:func:`fwnode_pcs_simple_get` can be used as the get function.
+
+You must call :c:func:`fwnode_pcs_del_provider` from your remove function
+on driver detach.
+
+A devm variant, :c:func:`devm_fwnode_pcs_add_provider`, is available to
+automatically release the PCS provider on driver detach.
+
+Late PCS registration handling
+------------------------------
+
+It's possible that a PCS becomes available after the MAC finished probing.
+Contrary to the usual producer/consumer implementation, when a PCS is not
+registered and can't be found, the fwnode parser helper returns ``-ENODEV``
+instead of ``-EPROBE_DEFER``.
+
+This is to prevent race condition with particular devices that register
+MAC and PCS with USB or PCIe and require the MAC to be registered before
+the PCS.
+
+The phylink logic correctly handle this special case and keep the phylink
+instance in a fail condition.
+
+The PCS fwnode implementation provides a notifier to which each phylink
+instance with a non-empty ``pcs_interfaces`` in :c:type:`phylink_config`
+registers. When a new PCS provider is registered, the notifier is called
+triggering the :c:func:`pcs_provider_notify` function.
+
+Function :c:func:`pcs_provider_notify` will check if the just added PCS
+should be used by the phylink instance. If it should be used then,
+it's added to the internal list of available PCS and a phylink major
+config is forced.
+
+If a phylink instance was in a failure state, with the just added PCS
+now part of the available PCS internal phylink list, provided all other
+conditions are satisfied, the configuration is retried and the failure
+condition is cleared.
+
+API Reference
+-------------
+
+.. kernel-doc:: include/linux/phylink.h
+   :identifiers: phylink_pcs
+
+.. kernel-doc:: include/linux/pcs/pcs.h
+   :internal:
+
+.. kernel-doc:: include/linux/pcs/pcs-provider.h
+   :internal:
diff --git a/Documentation/networking/sfp-phylink.rst b/Documentation/networking/sfp-phylink.rst
index 5bf285d73e8a..306505118eba 100644
--- a/Documentation/networking/sfp-phylink.rst
+++ b/Documentation/networking/sfp-phylink.rst
@@ -311,33 +311,20 @@ this documentation.
 
         priv->pcs = lynx_pcs_create_mdiodev(bus, 0);
 
-    Some PCS can be recovered based on firmware information:
+    PCS that should be recovered based on firmware information should implement
+    the external PCS as a :ref:`PCS provider <pcs_producer>` and reference it
+    with the use of PCS fwnode helper :ref:`PCS fwnode helper <pcs_fwnode>`.
 
-    .. code-block:: c
-
-        priv->pcs = lynx_pcs_create_fwnode(of_fwnode_handle(node));
-
-12. Populate the :c:func:`mac_select_pcs` callback and add it to your
-    :c:type:`struct phylink_mac_ops <phylink_mac_ops>` set of ops. This function
-    must return a pointer to the relevant :c:type:`struct phylink_pcs <phylink_pcs>`
-    that will be used for the requested link configuration:
-
-    .. code-block:: c
-
-        static struct phylink_pcs *foo_select_pcs(struct phylink_config *config,
-                                                  phy_interface_t interface)
-        {
-                struct foo_priv *priv = container_of(config, struct foo_priv,
-                                                     phylink_config);
-
-                if ( /* 'interface' needs a PCS to function */ )
-                        return priv->pcs;
+12. Populate the :c:var:`num_possible_pcs` value and
+    :c:func:`fill_available_pcs` callback and add it to your
+    :c:type:`struct phylink_config <phylink_config>`.
 
-                return NULL;
-        }
+    Refer to :ref:`Documentation/networking/pcs.rst <pcs_consumer>` for
+    further details and examples.
 
-    See :c:func:`mvpp2_select_pcs` for an example of a driver that has multiple
-    internal PCS.
+    Notice that the previous implementation of populating
+    :c:func:`mac_select_pcs` is considered deprecated in favor of the new
+    described above.
 
 13. Fill-in all the :c:type:`phy_interface_t <phy_interface_t>` (i.e. all MAC to
     PHY link modes) that your MAC can output. The following example shows a
-- 
2.53.0

[PATCH net-next v11 08/12] MAINTAINERS: add myself as PCS subsystem maintainer

[Christian Marangi]

List all the files of the Ethernet PCS subsystem and add myself as
maintainer.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 MAINTAINERS | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 08e43bc09735..e3ded0e4a115 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9688,6 +9688,15 @@ F:	include/uapi/linux/if_bridge.h
 F:	include/linux/netfilter_bridge/
 F:	net/bridge/
 
+ETHERNET PCS SUBSYSTEM
+M:	Christian Marangi <ansuelsmth@gmail.com>
+L:	netdev@vger.kernel.org
+S:	Maintained
+F:	Documentation/networking/pcs.rst
+F:	drivers/net/pcs/pcs.c
+F:	include/linux/pcs/pcs-provider.h
+F:	include/linux/pcs/pcs.h
+
 ETHERNET PHY LIBRARY
 M:	Andrew Lunn <andrew@lunn.ch>
 M:	Heiner Kallweit <hkallweit1@gmail.com>
-- 
2.53.0

[PATCH net-next v11 09/12] net: phylink: add .pcs_link_down PCS OP

[Christian Marangi]

Permit for PCS driver to define specific operation to tear down the link
between the MAC and the PCS.

This might be needed for some PCS that reset counter or require special
reset to correctly work if the link needs to be restored later.

On phylink_link_down() call, the additional phylink_pcs_link_down() will
be called after .mac_link_down to tear down the link.

PCS driver will need to define .pcs_link_down to make use of this.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 drivers/net/phy/phylink.c |  9 +++++++++
 include/linux/phylink.h   | 12 ++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 69d4f6675db0..2e8d11573e3a 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -982,6 +982,12 @@ static void phylink_pcs_link_up(struct phylink_pcs *pcs, unsigned int neg_mode,
 		pcs->ops->pcs_link_up(pcs, neg_mode, interface, speed, duplex);
 }
 
+static void phylink_pcs_link_down(struct phylink_pcs *pcs)
+{
+	if (pcs && pcs->ops->pcs_link_down)
+		pcs->ops->pcs_link_down(pcs);
+}
+
 static void phylink_pcs_disable_eee(struct phylink_pcs *pcs)
 {
 	if (pcs && pcs->ops->pcs_disable_eee)
@@ -1683,6 +1689,9 @@ static void phylink_link_down(struct phylink *pl)
 
 	pl->mac_ops->mac_link_down(pl->config, pl->act_link_an_mode,
 				   pl->cur_interface);
+
+	phylink_pcs_link_down(pl->pcs);
+
 	phylink_info(pl, "Link is Down\n");
 }
 
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index ca9dfc142388..ea554c0d41f8 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -528,6 +528,7 @@ struct phylink_pcs {
  * @pcs_an_restart: restart 802.3z BaseX autonegotiation.
  * @pcs_link_up: program the PCS for the resolved link configuration
  *               (where necessary).
+ * @pcs_link_down: tear down link between MAC and PCS.
  * @pcs_disable_eee: optional notification to PCS that EEE has been disabled
  *		     at the MAC.
  * @pcs_enable_eee: optional notification to PCS that EEE will be enabled at
@@ -555,6 +556,7 @@ struct phylink_pcs_ops {
 	void (*pcs_an_restart)(struct phylink_pcs *pcs);
 	void (*pcs_link_up)(struct phylink_pcs *pcs, unsigned int neg_mode,
 			    phy_interface_t interface, int speed, int duplex);
+	void (*pcs_link_down)(struct phylink_pcs *pcs);
 	void (*pcs_disable_eee)(struct phylink_pcs *pcs);
 	void (*pcs_enable_eee)(struct phylink_pcs *pcs);
 	int (*pcs_pre_init)(struct phylink_pcs *pcs);
@@ -690,6 +692,16 @@ void pcs_an_restart(struct phylink_pcs *pcs);
 void pcs_link_up(struct phylink_pcs *pcs, unsigned int neg_mode,
 		 phy_interface_t interface, int speed, int duplex);
 
+/**
+ * pcs_link_down() - tear down link between MAC and PCS
+ * @pcs: a pointer to a &struct phylink_pcs.
+ *
+ * This call will be made just after mac_link_down() to inform the PCS the
+ * link has gone down. PCS should be configured to stop processing packets
+ * for transmission and reception.
+ */
+void pcs_link_down(struct phylink_pcs *pcs);
+
 /**
  * pcs_disable_eee() - Disable EEE at the PCS
  * @pcs: a pointer to a &struct phylink_pcs
-- 
2.53.0

[PATCH net-next v11 10/12] dt-bindings: net: pcs: Document support for Airoha Ethernet PCS

[Christian Marangi]

Document support for Airoha Ethernet PCS for AN7581 SoC.

Airoha AN7581 SoC expose multiple Physical Coding Sublayer (PCS) for
the various Serdes port supporting different Media Independent Interface
(10BASE-R, USXGMII, 2500BASE-X, 1000BASE-X, SGMII).

This follow the new PCS provider with the use of #pcs-cells property.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 .../bindings/net/pcs/airoha,pcs.yaml          | 261 ++++++++++++++++++
 1 file changed, 261 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/pcs/airoha,pcs.yaml

diff --git a/Documentation/devicetree/bindings/net/pcs/airoha,pcs.yaml b/Documentation/devicetree/bindings/net/pcs/airoha,pcs.yaml
new file mode 100644
index 000000000000..9c1d116c1b01
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/pcs/airoha,pcs.yaml
@@ -0,0 +1,261 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/pcs/airoha,pcs.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Airoha Ethernet PCS and Serdes
+
+maintainers:
+  - Christian Marangi <ansuelsmth@gmail.com>
+
+description:
+  Airoha AN7581 SoC expose multiple Physical Coding Sublayer (PCS) for
+  the various Serdes port supporting different Media Independent Interface
+  (10BASE-R, USXGMII, 2500BASE-X, 1000BASE-X, SGMII).
+
+properties:
+  compatible:
+    enum:
+      - airoha,an7581-pcs-eth
+      - airoha,an7581-pcs-pon
+      - airoha,an7581-pcs-pcie
+      - airoha,an7581-pcs-usb
+
+  reg:
+    minItems: 6
+    maxItems: 15
+
+  reg-names:
+    minItems: 6
+    maxItems: 15
+
+  airoha,scu:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: phandle to the SCU node required to configure
+      the serdes line to the correct interface mode.
+
+  phys:
+    maxItems: 1
+
+  "#pcs-cells": true
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - "#pcs-cells"
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - airoha,an7581-pcs-eth
+              - airoha,an7581-pcs-pon
+
+    then:
+      properties:
+        reg:
+          items:
+            - description: PCS MAC reg
+            - description: HSGMII AN reg
+            - description: HSGMII PCS reg
+            - description: MULTI SGMII reg
+            - description: USXGMII reg
+            - description: HSGMII rate adaption reg
+            - description: PCS Analog register
+            - description: PCS PMA (Physical Medium Attachment) register
+
+        reg-names:
+          items:
+            - const: pcs_mac
+            - const: hsgmii_an
+            - const: hsgmii_pcs
+            - const: multi_sgmii
+            - const: usxgmii
+            - const: hsgmii_rate_adp
+            - const: pcs_ana
+            - const: pcs_pma
+
+        phys: false
+
+        "#pcs-cells":
+          const: 0
+
+      required:
+        - airoha,scu
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: airoha,an7581-pcs-pcie
+
+    then:
+      properties:
+        reg:
+          items:
+            - description: PCS MAC 0 reg
+            - description: HSGMII AN 0 reg
+            - description: HSGMII PCS 0 reg
+            - description: MULTI SGMII 0 reg
+            - description: USXGMII 0 reg
+            - description: HSGMII rate adaption 0 reg
+            - description: PCS MAC 1 reg
+            - description: HSGMII AN 1 reg
+            - description: HSGMII PCS 1 reg
+            - description: MULTI SGMII 1 reg
+            - description: USXGMII 1 reg
+            - description: HSGMII rate adaption 1 reg
+            - description: PCS Analog register
+            - description: PCS PMA (Physical Medium Attachment) 0 register
+            - description: PCS PMA (Physical Medium Attachment) 1 register
+
+        reg-names:
+          items:
+            - const: pcs_mac0
+            - const: hsgmii_an0
+            - const: hsgmii_pcs0
+            - const: multi_sgmii0
+            - const: usxgmii0
+            - const: hsgmii_rate_adp0
+            - const: pcs_mac1
+            - const: hsgmii_an1
+            - const: hsgmii_pcs1
+            - const: multi_sgmii1
+            - const: usxgmii1
+            - const: hsgmii_rate_adp1
+            - const: pcs_ana
+            - const: pcs_pma0
+            - const: pcs_pma1
+
+        phys: false
+
+        "#pcs-cells":
+          const: 1
+
+      required:
+        - airoha,scu
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: airoha,an7581-pcs-usb
+
+    then:
+      properties:
+        reg:
+          items:
+            - description: PCS MAC reg
+            - description: HSGMII AN reg
+            - description: HSGMII PCS reg
+            - description: MULTI SGMII reg
+            - description: HSGMII rate adaption reg
+            - description: PCS Analog register
+
+        reg-names:
+          items:
+            - const: pcs_mac
+            - const: hsgmii_an
+            - const: hsgmii_pcs
+            - const: multi_sgmii
+            - const: hsgmii_rate_adp
+            - const: pcs_ana
+
+        airoha,scu: false
+
+        "#pcs-cells":
+          const: 0
+
+      required:
+        - phys
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/phy/phy.h>
+
+    pcs@1fa08000 {
+      compatible = "airoha,an7581-pcs-pon";
+      reg = <0x1fa08000 0x1000>,
+            <0x1fa80000 0x60>,
+            <0x1fa80a00 0x164>,
+            <0x1fa84000 0x450>,
+            <0x1fa85900 0x338>,
+            <0x1fa86000 0x300>,
+            <0x1fa8a000 0x1000>,
+            <0x1fa8b000 0x1000>;
+      reg-names = "pcs_mac", "hsgmii_an", "hsgmii_pcs",
+                  "multi_sgmii", "usxgmii",
+                  "hsgmii_rate_adp", "pcs_ana", "pcs_pma";
+
+      airoha,scu = <&scuclk>;
+      #pcs-cells = <0>;
+    };
+
+    pcs@1fa09000 {
+      compatible = "airoha,an7581-pcs-eth";
+      reg = <0x1fa09000 0x1000>,
+            <0x1fa70000 0x60>,
+            <0x1fa70a00 0x164>,
+            <0x1fa74000 0x450>,
+            <0x1fa75900 0x338>,
+            <0x1fa76000 0x300>,
+            <0x1fa7a000 0x1000>,
+            <0x1fa7b000 0x1000>;
+      reg-names = "pcs_mac", "hsgmii_an", "hsgmii_pcs",
+                  "multi_sgmii", "usxgmii",
+                  "hsgmii_rate_adp", "pcs_ana", "pcs_pma";
+
+      airoha,scu = <&scuclk>;
+      #pcs-cells = <0>;
+    };
+
+    pcs@1fa04000 {
+      compatible = "airoha,an7581-pcs-pcie";
+      reg = <0x1fa04000 0x1000>,
+            <0x1fa50000 0x60>,
+            <0x1fa50a00 0x164>,
+            <0x1fa54000 0x450>,
+            <0x1fa55900 0x338>,
+            <0x1fa56000 0x300>,
+            <0x1fa05000 0x1000>,
+            <0x1fa60000 0x60>,
+            <0x1fa60a00 0x164>,
+            <0x1fa64000 0x450>,
+            <0x1fa65900 0x338>,
+            <0x1fa66000 0x300>,
+            <0x1fa5a000 0x1000>,
+            <0x1fa5b000 0x1000>,
+            <0x1fa5c000 0x1000>;
+      reg-names = "pcs_mac0", "hsgmii_an0", "hsgmii_pcs0",
+                  "multi_sgmii0", "usxgmii0",
+                  "hsgmii_rate_adp0",
+                  "pcs_mac1", "hsgmii_an1", "hsgmii_pcs1",
+                  "multi_sgmii1", "usxgmii1",
+                  "hsgmii_rate_adp1",
+                  "pcs_ana", "pcs_pma0", "pcs_pma1";
+
+      airoha,scu = <&scuclk>;
+      #pcs-cells = <1>;
+    };
+
+    pcs@1fa07000 {
+      compatible = "airoha,an7581-pcs-usb";
+      reg = <0x1fa07000 0x1000>,
+            <0x1fa90000 0x60>,
+            <0x1fa90a00 0x164>,
+            <0x1fa94000 0x450>,
+            <0x1fa96000 0x300>,
+            <0x1fa9a000 0x600>;
+      reg-names = "pcs_mac", "hsgmii_an", "hsgmii_pcs",
+                  "multi_sgmii", "hsgmii_rate_adp","pcs_ana";
+
+      phys = <&usb0_phy PHY_TYPE_USB3>;
+
+      #pcs-cells = <0>;
+    };
-- 
2.53.0

[PATCH net-next v11 12/12] net: airoha: add phylink support

[Christian Marangi]

Add phylink support for each GDM port. For GDM1 add the internal interface
mode as the only supported mode. For GDM2/3/4 add the required
configuration of the PCS to make the external PHY or attached SFP cage
work.

These needs to be defined in the GDM port node using the pcs-handle
property.

Update and provide a .get/set_link_ksettings function that use phylink
for ethtool OPs now that we fully support phylink.

Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/ethernet/airoha/Kconfig       |   2 +
 drivers/net/ethernet/airoha/airoha_eth.c  | 190 +++++++++++++++++++++-
 drivers/net/ethernet/airoha/airoha_eth.h  |   5 +
 drivers/net/ethernet/airoha/airoha_regs.h |  12 ++
 4 files changed, 207 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/airoha/Kconfig b/drivers/net/ethernet/airoha/Kconfig
index 1f6640a15fc9..5c54a07d2a76 100644
--- a/drivers/net/ethernet/airoha/Kconfig
+++ b/drivers/net/ethernet/airoha/Kconfig
@@ -20,6 +20,8 @@ config NET_AIROHA
 	depends on NET_DSA || !NET_DSA
 	select NET_AIROHA_NPU
 	select PAGE_POOL
+	select PCS_AIROHA
+	select PHYLINK
 	help
 	  This driver supports the gigabit ethernet MACs in the
 	  Airoha SoC family.
diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 64619e9a704d..9fe8376aca0f 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -6,6 +6,7 @@
 #include <linux/of.h>
 #include <linux/of_net.h>
 #include <linux/of_reserved_mem.h>
+#include <linux/pcs/pcs.h>
 #include <linux/platform_device.h>
 #include <linux/tcp.h>
 #include <linux/u64_stats_sync.h>
@@ -1915,6 +1916,14 @@ static int airoha_dev_open(struct net_device *netdev)
 	struct airoha_qdma *qdma;
 	int err;
 
+	err = phylink_of_phy_connect(dev->phylink, netdev->dev.of_node, 0);
+	if (err) {
+		netdev_err(netdev, "could not attach PHY: %d\n", err);
+		return err;
+	}
+
+	phylink_start(dev->phylink);
+
 	netif_tx_start_all_queues(netdev);
 	err = airoha_set_vip_for_gdm_port(dev, true);
 	if (err)
@@ -1945,6 +1954,8 @@ static int airoha_dev_stop(struct net_device *netdev)
 	struct airoha_gdm_dev *dev = netdev_priv(netdev);
 	struct airoha_gdm_port *port = dev->port;
 
+	phylink_stop(dev->phylink);
+
 	netif_tx_disable(netdev);
 	airoha_set_vip_for_gdm_port(dev, false);
 
@@ -1954,6 +1965,9 @@ static int airoha_dev_stop(struct net_device *netdev)
 		airoha_set_gdm_port_fwd_cfg(dev->eth,
 					    REG_GDM_FWD_CFG(port->id),
 					    FE_PSE_PORT_DROP);
+
+	phylink_disconnect_phy(dev->phylink);
+
 	return 0;
 }
 
@@ -2509,6 +2523,24 @@ airoha_ethtool_get_rmon_stats(struct net_device *netdev,
 	} while (u64_stats_fetch_retry(&dev->stats.syncp, start));
 }
 
+static int
+airoha_ethtool_get_link_ksettings(struct net_device *netdev,
+				  struct ethtool_link_ksettings *cmd)
+{
+	struct airoha_gdm_dev *dev = netdev_priv(netdev);
+
+	return phylink_ethtool_ksettings_get(dev->phylink, cmd);
+}
+
+static int
+airoha_ethtool_set_link_ksettings(struct net_device *netdev,
+				  const struct ethtool_link_ksettings *cmd)
+{
+	struct airoha_gdm_dev *dev = netdev_priv(netdev);
+
+	return phylink_ethtool_ksettings_set(dev->phylink, cmd);
+}
+
 static int airoha_qdma_set_chan_tx_sched(struct net_device *netdev,
 					 int channel, enum tx_sched_mode mode,
 					 const u16 *weights, u8 n_weights)
@@ -3353,7 +3385,8 @@ static const struct ethtool_ops airoha_ethtool_ops = {
 	.get_drvinfo		= airoha_ethtool_get_drvinfo,
 	.get_eth_mac_stats      = airoha_ethtool_get_mac_stats,
 	.get_rmon_stats		= airoha_ethtool_get_rmon_stats,
-	.get_link_ksettings	= phy_ethtool_get_link_ksettings,
+	.get_link_ksettings	= airoha_ethtool_get_link_ksettings,
+	.set_link_ksettings	= airoha_ethtool_set_link_ksettings,
 	.get_link		= ethtool_op_get_link,
 };
 
@@ -3409,6 +3442,155 @@ bool airoha_is_valid_gdm_dev(struct airoha_eth *eth,
 	return false;
 }
 
+/* Nothing to do in MAC, everything is handled in PCS */
+static void airoha_mac_config(struct phylink_config *config, unsigned int mode,
+			      const struct phylink_link_state *state)
+{
+}
+
+static void airoha_mac_link_up(struct phylink_config *config, struct phy_device *phy,
+			       unsigned int mode, phy_interface_t interface,
+			       int speed, int duplex, bool tx_pause, bool rx_pause)
+{
+	struct airoha_gdm_dev *dev = container_of(config, struct airoha_gdm_dev,
+						  phylink_config);
+	struct airoha_gdm_port *port = dev->port;
+	struct airoha_eth *eth = dev->eth;
+	u32 frag_size_tx, frag_size_rx;
+
+	/* TX/RX frag is configured only for GDM4 */
+	if (port->id != AIROHA_GDM4_IDX)
+		return;
+
+	switch (speed) {
+	case SPEED_10000:
+	case SPEED_5000:
+		frag_size_tx = 8;
+		frag_size_rx = 8;
+		break;
+	case SPEED_2500:
+		frag_size_tx = 2;
+		frag_size_rx = 1;
+		break;
+	default:
+		frag_size_tx = 1;
+		frag_size_rx = 0;
+		break;
+	}
+
+	mutex_lock(&port->link_lock);
+
+	/* Configure TX/RX frag based on speed */
+	if (dev->nbq == 1) {
+		airoha_fe_rmw(eth, REG_FE_GDM4_TMBI_FRAG,
+			      GDM4_SGMII1_TX_FRAG_SIZE_MASK,
+			      FIELD_PREP(GDM4_SGMII1_TX_FRAG_SIZE_MASK,
+					 frag_size_tx));
+
+		airoha_fe_rmw(eth, REG_FE_GDM4_RMBI_FRAG,
+			      GDM4_SGMII1_RX_FRAG_SIZE_MASK,
+			      FIELD_PREP(GDM4_SGMII1_RX_FRAG_SIZE_MASK,
+					 frag_size_rx));
+	} else {
+		airoha_fe_rmw(eth, REG_FE_GDM4_TMBI_FRAG,
+			      GDM4_SGMII0_TX_FRAG_SIZE_MASK,
+			      FIELD_PREP(GDM4_SGMII0_TX_FRAG_SIZE_MASK,
+					 frag_size_tx));
+
+		airoha_fe_rmw(eth, REG_FE_GDM4_RMBI_FRAG,
+			      GDM4_SGMII0_RX_FRAG_SIZE_MASK,
+			      FIELD_PREP(GDM4_SGMII0_RX_FRAG_SIZE_MASK,
+					 frag_size_rx));
+	}
+
+	mutex_unlock(&port->link_lock);
+}
+
+/* Nothing to do in MAC, everything is handled in PCS */
+static void airoha_mac_link_down(struct phylink_config *config, unsigned int mode,
+				 phy_interface_t interface)
+{
+}
+
+static const struct phylink_mac_ops airoha_phylink_ops = {
+	.mac_config = airoha_mac_config,
+	.mac_link_up = airoha_mac_link_up,
+	.mac_link_down = airoha_mac_link_down,
+};
+
+static int airoha_fill_available_pcs(struct phylink_config *config,
+				     struct phylink_pcs **available_pcs,
+				     unsigned int num_possible_pcs)
+{
+	struct device *dev = config->dev;
+
+	return fwnode_phylink_pcs_parse(dev_fwnode(dev), available_pcs,
+					num_possible_pcs);
+}
+
+static int airoha_setup_phylink(struct net_device *netdev)
+{
+	struct airoha_gdm_dev *dev = netdev_priv(netdev);
+	struct device_node *np = netdev->dev.of_node;
+	struct airoha_gdm_port *port = dev->port;
+	struct phylink_config *config;
+	phy_interface_t phy_mode;
+	struct phylink *phylink;
+	int err;
+
+	err = of_get_phy_mode(np, &phy_mode);
+	if (err) {
+		dev_err(&netdev->dev, "incorrect phy-mode\n");
+		return err;
+	}
+
+	config = &dev->phylink_config;
+	config->dev = &netdev->dev;
+	config->type = PHYLINK_NETDEV;
+
+	/*
+	 * GDM1 only supports internal for Embedded Switch
+	 * and doesn't require a PCS.
+	 */
+	if (port->id == AIROHA_GDM1_IDX) {
+		config->mac_capabilities = MAC_ASYM_PAUSE | MAC_SYM_PAUSE |
+					   MAC_10000FD;
+
+		__set_bit(PHY_INTERFACE_MODE_INTERNAL,
+			  config->supported_interfaces);
+	} else {
+		config->mac_capabilities = MAC_ASYM_PAUSE | MAC_SYM_PAUSE |
+					   MAC_10 | MAC_100 | MAC_1000 |
+					   MAC_2500FD | MAC_5000FD | MAC_10000FD;
+
+		config->num_possible_pcs = fwnode_phylink_pcs_count(dev_fwnode(config->dev));
+		config->fill_available_pcs = airoha_fill_available_pcs;
+
+		__set_bit(PHY_INTERFACE_MODE_SGMII,
+			  config->supported_interfaces);
+		__set_bit(PHY_INTERFACE_MODE_1000BASEX,
+			  config->supported_interfaces);
+		__set_bit(PHY_INTERFACE_MODE_2500BASEX,
+			  config->supported_interfaces);
+		__set_bit(PHY_INTERFACE_MODE_10GBASER,
+			  config->supported_interfaces);
+		__set_bit(PHY_INTERFACE_MODE_USXGMII,
+			  config->supported_interfaces);
+
+		phy_interface_copy(config->pcs_interfaces,
+				   config->supported_interfaces);
+	}
+
+	phylink = phylink_create(config, of_fwnode_handle(np),
+				 phy_mode, &airoha_phylink_ops);
+	if (IS_ERR(phylink))
+		return PTR_ERR(phylink);
+
+	dev->phylink = phylink;
+
+	return 0;
+}
+
 static int airoha_alloc_gdm_device(struct airoha_eth *eth,
 				   struct airoha_gdm_port *port,
 				   int nbq, struct device_node *np)
@@ -3474,7 +3656,7 @@ static int airoha_alloc_gdm_device(struct airoha_eth *eth,
 	dev->nbq = nbq;
 	port->devs[index] = dev;
 
-	return 0;
+	return airoha_setup_phylink(netdev);
 }
 
 static int airoha_alloc_gdm_port(struct airoha_eth *eth,
@@ -3510,6 +3692,7 @@ static int airoha_alloc_gdm_port(struct airoha_eth *eth,
 
 	port->id = id;
 	spin_lock_init(&port->stats_lock);
+	mutex_init(&port->link_lock);
 	eth->ports[p] = port;
 
 	err = airoha_metadata_dst_alloc(port);
@@ -3706,6 +3889,8 @@ static int airoha_probe(struct platform_device *pdev)
 			netdev = netdev_from_priv(dev);
 			if (netdev->reg_state == NETREG_REGISTERED)
 				unregister_netdev(netdev);
+			if (dev->phylink)
+				phylink_destroy(dev->phylink);
 			of_node_put(netdev->dev.of_node);
 		}
 		airoha_metadata_dst_free(port);
@@ -3744,6 +3929,7 @@ static void airoha_remove(struct platform_device *pdev)
 
 			netdev = netdev_from_priv(dev);
 			unregister_netdev(netdev);
+			phylink_destroy(dev->phylink);
 			of_node_put(netdev->dev.of_node);
 		}
 		airoha_metadata_dst_free(port);
diff --git a/drivers/net/ethernet/airoha/airoha_eth.h b/drivers/net/ethernet/airoha/airoha_eth.h
index fa9a8edce22f..83daec003257 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.h
+++ b/drivers/net/ethernet/airoha/airoha_eth.h
@@ -595,6 +595,9 @@ struct airoha_gdm_dev {
 	 * QDMA migration.
 	 */
 	spinlock_t txq_lock[AIROHA_NUM_NETDEV_TX_RINGS];
+
+	struct phylink *phylink;
+	struct phylink_config phylink_config;
 };
 
 struct airoha_gdm_port {
@@ -604,6 +607,8 @@ struct airoha_gdm_port {
 
 	/* protect concurrent hw_stats accesses */
 	spinlock_t stats_lock;
+	/* protect concurrent GDM4 register access */
+	struct mutex link_lock;
 
 	struct metadata_dst *dsa_meta[AIROHA_MAX_DSA_PORTS];
 };
diff --git a/drivers/net/ethernet/airoha/airoha_regs.h b/drivers/net/ethernet/airoha/airoha_regs.h
index 442b48c9b991..4ea89057b560 100644
--- a/drivers/net/ethernet/airoha/airoha_regs.h
+++ b/drivers/net/ethernet/airoha/airoha_regs.h
@@ -357,6 +357,18 @@
 #define IP_FRAGMENT_PORT_MASK		GENMASK(8, 5)
 #define IP_FRAGMENT_NBQ_MASK		GENMASK(4, 0)
 
+#define REG_FE_GDM4_TMBI_FRAG		0x2028
+#define GDM4_SGMII1_TX_WEIGHT_MASK	GENMASK(31, 26)
+#define GDM4_SGMII1_TX_FRAG_SIZE_MASK	GENMASK(25, 16)
+#define GDM4_SGMII0_TX_WEIGHT_MASK	GENMASK(15, 10)
+#define GDM4_SGMII0_TX_FRAG_SIZE_MASK	GENMASK(9, 0)
+
+#define REG_FE_GDM4_RMBI_FRAG		0x202c
+#define GDM4_SGMII1_RX_WEIGHT_MASK	GENMASK(31, 26)
+#define GDM4_SGMII1_RX_FRAG_SIZE_MASK	GENMASK(25, 16)
+#define GDM4_SGMII0_RX_WEIGHT_MASK	GENMASK(15, 10)
+#define GDM4_SGMII0_RX_FRAG_SIZE_MASK	GENMASK(9, 0)
+
 #define REG_MC_VLAN_EN			0x2100
 #define MC_VLAN_EN_MASK			BIT(0)
 
-- 
2.53.0

Re: [PATCH net-next v11 03/12] net: pcs: implement Firmware node support for PCS driver

[Randy Dunlap]

Hi--

On 8/7/26 6:12 AM, Christian Marangi wrote:
> Implement the foundation of Firmware node support for PCS driver.
> 

> 
> Co-developed-by: Daniel Golle <daniel@makrotopia.org>
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---
>  drivers/net/pcs/Kconfig          |   6 +
>  drivers/net/pcs/Makefile         |   1 +
>  drivers/net/pcs/pcs.c            | 240 +++++++++++++++++++++++++++++++
>  include/linux/pcs/pcs-provider.h |  65 +++++++++
>  include/linux/pcs/pcs.h          |  75 ++++++++++
>  5 files changed, 387 insertions(+)
>  create mode 100644 drivers/net/pcs/pcs.c
>  create mode 100644 include/linux/pcs/pcs-provider.h
>  create mode 100644 include/linux/pcs/pcs.h
> 


Please address these warnings:

WARNING: ../include/linux/pcs/pcs-provider.h:39 function parameter 'pp' not described in 'fwnode_pcs_del_provider'
WARNING: ../include/linux/pcs/pcs-provider.h:39 Excess function parameter 'fwnode' description in 'fwnode_pcs_del_provider'
WARNING: ../include/linux/pcs/pcs-provider.h:62 expecting prototype for fwnode_pcs_add_provider(). Prototype was for devm_fwnode_pcs_add_provider() instead

> diff --git a/include/linux/pcs/pcs-provider.h b/include/linux/pcs/pcs-provider.h
> new file mode 100644
> index 000000000000..5df48022bc6e
> --- /dev/null
> +++ b/include/linux/pcs/pcs-provider.h
> @@ -0,0 +1,65 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +#ifndef __LINUX_PCS_PROVIDER_H
> +#define __LINUX_PCS_PROVIDER_H
> +
> +struct fwnode_pcs_provider;
> +
> +/**
> + * fwnode_pcs_simple_get - Simple xlate function to retrieve PCS
> + * @pcsspec: reference arguments
> + * @data: Context data (assumed assigned to the single PCS)
> + *
> + * Returns: the PCS pointed by data.
> + */
> +struct phylink_pcs *fwnode_pcs_simple_get(struct fwnode_reference_args *pcsspec,
> +					  void *data);
> +
> +/**
> + * fwnode_pcs_add_provider - Registers a new PCS provider
> + * @fwnode: Firmware node
> + * @get: xlate function to retrieve the PCS
> + * @data: Context data
> + *
> + * Register and add a new PCS provider to the global providers list
> + * for the firmware node. The relevant PCS from the PCS provider
> + * is retrieved from the passed xlate function.
> + *
> + * Returns: A pointer to the registered PCS provider on success, or
> + * an ERR_PTR() encoded error code on failure.
> + */
> +struct fwnode_pcs_provider *
> +fwnode_pcs_add_provider(struct fwnode_handle *fwnode,
> +			struct phylink_pcs *(*get)(struct fwnode_reference_args *pcsspec,
> +						   void *data),
> +			void *data);
> +
> +/**
> + * fwnode_pcs_del_provider - Removes a PCS provider
> + * @fwnode: Firmware node
> + */
> +void fwnode_pcs_del_provider(struct fwnode_pcs_provider *pp);
> +
> +/**
> + * fwnode_pcs_add_provider - Registers a new PCS provider
> + * @dev: Device of the PCS provider
> + * @fwnode: Firmware node
> + * @get: xlate function to retrieve the PCS
> + * @data: Context data
> + *
> + * Register and add a new PCS provider to the global providers list
> + * for the firmware node. The relevant PCS from the PCS provider
> + * is retrieved from the passed xlate function. While at that, it
> + * also associates the device with the PCS provider using devres.
> + * On driver detach, release function is invoked on the devres data,
> + * then, devres data is freed.
> + *
> + * Returns: A pointer to the registered PCS provider on success, or
> + * an ERR_PTR() encoded error code on failure.
> + */
> +struct fwnode_pcs_provider *
> +devm_fwnode_pcs_add_provider(struct device *dev, struct fwnode_handle *fwnode,
> +			     struct phylink_pcs *(*get)(struct fwnode_reference_args *pcsspec,
> +							void *data),
> +			     void *data);
> +
> +#endif /* __LINUX_PCS_PROVIDER_H */

thanks.

-- 
~Randy

Re: [PATCH net-next v11 03/12] net: pcs: implement Firmware node support for PCS driver

[Christian Marangi]

On Fri, Aug 07, 2026 at 01:29:41PM -0700, Randy Dunlap wrote:
> Hi--
> 
> On 8/7/26 6:12 AM, Christian Marangi wrote:
> > Implement the foundation of Firmware node support for PCS driver.
> > 
> 
> > 
> > Co-developed-by: Daniel Golle <daniel@makrotopia.org>
> > Signed-off-by: Daniel Golle <daniel@makrotopia.org>
> > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > ---
> >  drivers/net/pcs/Kconfig          |   6 +
> >  drivers/net/pcs/Makefile         |   1 +
> >  drivers/net/pcs/pcs.c            | 240 +++++++++++++++++++++++++++++++
> >  include/linux/pcs/pcs-provider.h |  65 +++++++++
> >  include/linux/pcs/pcs.h          |  75 ++++++++++
> >  5 files changed, 387 insertions(+)
> >  create mode 100644 drivers/net/pcs/pcs.c
> >  create mode 100644 include/linux/pcs/pcs-provider.h
> >  create mode 100644 include/linux/pcs/pcs.h
> > 
> 
> 
> Please address these warnings:
> 
> WARNING: ../include/linux/pcs/pcs-provider.h:39 function parameter 'pp' not described in 'fwnode_pcs_del_provider'
> WARNING: ../include/linux/pcs/pcs-provider.h:39 Excess function parameter 'fwnode' description in 'fwnode_pcs_del_provider'
> WARNING: ../include/linux/pcs/pcs-provider.h:62 expecting prototype for fwnode_pcs_add_provider(). Prototype was for devm_fwnode_pcs_add_provider() instead
>

Yep, they slipped in the rework. I already fixed these, just waiting the
usual 24h.
 
> > diff --git a/include/linux/pcs/pcs-provider.h b/include/linux/pcs/pcs-provider.h
> > new file mode 100644
> > index 000000000000..5df48022bc6e
> > --- /dev/null
> > +++ b/include/linux/pcs/pcs-provider.h
> > @@ -0,0 +1,65 @@
> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
> > +#ifndef __LINUX_PCS_PROVIDER_H
> > +#define __LINUX_PCS_PROVIDER_H
> > +
> > +struct fwnode_pcs_provider;
> > +
> > +/**
> > + * fwnode_pcs_simple_get - Simple xlate function to retrieve PCS
> > + * @pcsspec: reference arguments
> > + * @data: Context data (assumed assigned to the single PCS)
> > + *
> > + * Returns: the PCS pointed by data.
> > + */
> > +struct phylink_pcs *fwnode_pcs_simple_get(struct fwnode_reference_args *pcsspec,
> > +					  void *data);
> > +
> > +/**
> > + * fwnode_pcs_add_provider - Registers a new PCS provider
> > + * @fwnode: Firmware node
> > + * @get: xlate function to retrieve the PCS
> > + * @data: Context data
> > + *
> > + * Register and add a new PCS provider to the global providers list
> > + * for the firmware node. The relevant PCS from the PCS provider
> > + * is retrieved from the passed xlate function.
> > + *
> > + * Returns: A pointer to the registered PCS provider on success, or
> > + * an ERR_PTR() encoded error code on failure.
> > + */
> > +struct fwnode_pcs_provider *
> > +fwnode_pcs_add_provider(struct fwnode_handle *fwnode,
> > +			struct phylink_pcs *(*get)(struct fwnode_reference_args *pcsspec,
> > +						   void *data),
> > +			void *data);
> > +
> > +/**
> > + * fwnode_pcs_del_provider - Removes a PCS provider
> > + * @fwnode: Firmware node
> > + */
> > +void fwnode_pcs_del_provider(struct fwnode_pcs_provider *pp);
> > +
> > +/**
> > + * fwnode_pcs_add_provider - Registers a new PCS provider
> > + * @dev: Device of the PCS provider
> > + * @fwnode: Firmware node
> > + * @get: xlate function to retrieve the PCS
> > + * @data: Context data
> > + *
> > + * Register and add a new PCS provider to the global providers list
> > + * for the firmware node. The relevant PCS from the PCS provider
> > + * is retrieved from the passed xlate function. While at that, it
> > + * also associates the device with the PCS provider using devres.
> > + * On driver detach, release function is invoked on the devres data,
> > + * then, devres data is freed.
> > + *
> > + * Returns: A pointer to the registered PCS provider on success, or
> > + * an ERR_PTR() encoded error code on failure.
> > + */
> > +struct fwnode_pcs_provider *
> > +devm_fwnode_pcs_add_provider(struct device *dev, struct fwnode_handle *fwnode,
> > +			     struct phylink_pcs *(*get)(struct fwnode_reference_args *pcsspec,
> > +							void *data),
> > +			     void *data);
> > +
> > +#endif /* __LINUX_PCS_PROVIDER_H */
> 
> thanks.
> 
> -- 
> ~Randy
> 

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