Commit dceb393a authored by Romain Gantois's avatar Romain Gantois Committed by Jakub Kicinski
Browse files

net: phylink: add rxc_always_on flag to phylink_pcs 



Some MAC drivers (e.g. stmmac) require a continuous receive clock signal to
be generated by a PCS that is handled by a standalone PCS driver.

Such a PCS driver does not have access to a PHY device, thus cannot check
the PHY_F_RXC_ALWAYS_ON flag. They cannot check max_requires_rxc in the
phylink config either, since it is a private member. Therefore, a new flag
is needed to signal to the PCS that it should keep the RX clock signal up
at all times.

Co-developed-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarRomain Gantois <romain.gantois@bootlin.com>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240326-rxc_bugfix-v6-2-24a74e5c761f@bootlin.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 21d9ba5b

drivers/net/phy/phylink.c

+15 −0
Original line number Diff line number Diff line
@@ -1042,6 +1042,21 @@ static void phylink_pcs_poll_start(struct phylink *pl) 
		mod_timer(&pl->link_poll, jiffies + HZ);

}



int phylink_pcs_pre_init(struct phylink *pl, struct phylink_pcs *pcs)

{

	int ret = 0;



	/* Signal to PCS driver that MAC requires RX clock for init */

	if (pl->config->mac_requires_rxc)

		pcs->rxc_always_on = true;



	if (pcs->ops->pcs_pre_init)

		ret = pcs->ops->pcs_pre_init(pcs);



	return ret;

}

EXPORT_SYMBOL_GPL(phylink_pcs_pre_init);



static void phylink_mac_config(struct phylink *pl,

			       const struct phylink_link_state *state)

{

include/linux/phylink.h

+38 −0
Original line number Diff line number Diff line
@@ -396,6 +396,10 @@ struct phylink_pcs_ops; 
 * @phylink: pointer to &struct phylink_config

 * @neg_mode: provide PCS neg mode via "mode" argument

 * @poll: poll the PCS for link changes

 * @rxc_always_on: The MAC driver requires the reference clock

 *                 to always be on. Standalone PCS drivers which

 *                 do not have access to a PHY device can check

 *                 this instead of PHY_F_RXC_ALWAYS_ON.

 *

 * This structure is designed to be embedded within the PCS private data,

 * and will be passed between phylink and the PCS.
@@ -408,6 +412,7 @@ struct phylink_pcs { 
	struct phylink *phylink;

	bool neg_mode;

	bool poll;

	bool rxc_always_on;

};



/**
@@ -422,6 +427,8 @@ 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_pre_init: configure PCS components necessary for MAC hardware

 *                initialization e.g. RX clock for stmmac.

 */

struct phylink_pcs_ops {

	int (*pcs_validate)(struct phylink_pcs *pcs, unsigned long *supported,
@@ -441,6 +448,7 @@ 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);

	int (*pcs_pre_init)(struct phylink_pcs *pcs);

};



#if 0 /* For kernel-doc purposes only. */
@@ -546,6 +554,34 @@ 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_pre_init() - Configure PCS components necessary for MAC initialization

 * @pcs: a pointer to a &struct phylink_pcs.

 *

 * This function can be called by MAC drivers through the

 * phylink_pcs_pre_init() wrapper, before their hardware is initialized. It

 * should not be called after the link is brought up, as reconfiguring the PCS

 * at this point could break the link.

 *

 * Some MAC devices require specific hardware initialization to be performed by

 * their associated PCS device before they can properly initialize their own

 * hardware. An example of this is the initialization of stmmac controllers,

 * which requires an active REF_CLK signal to be provided by the PHY/PCS.

 *

 * By calling phylink_pcs_pre_init(), MAC drivers can ensure that the PCS is

 * setup in a way that allows for successful hardware initialization.

 *

 * The specific configuration performed by pcs_pre_init() is dependent on the

 * model of PCS and the requirements of the MAC device attached to it. PCS

 * driver authors should consider whether their target device is to be used in

 * conjunction with a MAC device whose driver calls phylink_pcs_pre_init(). MAC

 * driver authors should document their requirements for the PCS

 * pre-initialization.

 *

 */

int pcs_pre_init(struct phylink_pcs *pcs);



#endif



struct phylink *phylink_create(struct phylink_config *,
@@ -565,6 +601,8 @@ void phylink_disconnect_phy(struct phylink *); 
void phylink_mac_change(struct phylink *, bool up);

void phylink_pcs_change(struct phylink_pcs *, bool up);



int phylink_pcs_pre_init(struct phylink *pl, struct phylink_pcs *pcs);



void phylink_start(struct phylink *);

void phylink_stop(struct phylink *);