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net: phylink: add rxc_always_on flag to phylink_pcs

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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: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240326-rxc_bugfix-v6-2-24a74e5c761f@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Romain Gantois 2024-03-26 14:32:08 +01:00 committed by Jakub Kicinski
parent 21d9ba5bc5
commit dceb393a0a
2 changed files with 53 additions and 0 deletions
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15
drivers/net/phy/phylink.c
View File

@ -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)
{

38
include/linux/phylink.h
View File

@ -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 *);