Commit 883a98ed authored by Russell King (Oracle)'s avatar Russell King (Oracle) Committed by Jakub Kicinski
Browse files

net: pcs: xpcs: avoid reading STAT1 more than once 



Avoid reading the STAT1 registers more than once while getting the PCS
state, as this register contains latching-low bits that are lost after
the first read.

Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 21234ef1

drivers/net/pcs/pcs-xpcs.c

+50 −41
Original line number Diff line number Diff line
@@ -271,15 +271,12 @@ static int xpcs_soft_reset(struct dw_xpcs *xpcs, 
})



static int xpcs_read_fault_c73(struct dw_xpcs *xpcs,

			       struct phylink_link_state *state)

			       struct phylink_link_state *state,

			       u16 pcs_stat1)

{

	int ret;



	ret = xpcs_read(xpcs, MDIO_MMD_PCS, MDIO_STAT1);

	if (ret < 0)

		return ret;



	if (ret & MDIO_STAT1_FAULT) {

	if (pcs_stat1 & MDIO_STAT1_FAULT) {

		xpcs_warn(xpcs, state, "Link fault condition detected!\n");

		return -EFAULT;

	}
@@ -321,21 +318,6 @@ static int xpcs_read_fault_c73(struct dw_xpcs *xpcs, 
	return 0;

}



static int xpcs_read_link_c73(struct dw_xpcs *xpcs)

{

	bool link = true;

	int ret;



	ret = xpcs_read(xpcs, MDIO_MMD_PCS, MDIO_STAT1);

	if (ret < 0)

		return ret;



	if (!(ret & MDIO_STAT1_LSTATUS))

		link = false;



	return link;

}



static void xpcs_config_usxgmii(struct dw_xpcs *xpcs, int speed)

{

	int ret, speed_sel;
@@ -462,15 +444,11 @@ static int xpcs_config_aneg_c73(struct dw_xpcs *xpcs, 


static int xpcs_aneg_done_c73(struct dw_xpcs *xpcs,

			      struct phylink_link_state *state,

			      const struct xpcs_compat *compat)

			      const struct xpcs_compat *compat, u16 an_stat1)

{

	int ret;



	ret = xpcs_read(xpcs, MDIO_MMD_AN, MDIO_STAT1);

	if (ret < 0)

		return ret;



	if (ret & MDIO_AN_STAT1_COMPLETE) {

	if (an_stat1 & MDIO_AN_STAT1_COMPLETE) {

		ret = xpcs_read(xpcs, MDIO_MMD_AN, MDIO_AN_LPA);

		if (ret < 0)

			return ret;
@@ -488,16 +466,12 @@ static int xpcs_aneg_done_c73(struct dw_xpcs *xpcs, 
}



static int xpcs_read_lpa_c73(struct dw_xpcs *xpcs,

			     struct phylink_link_state *state)

			     struct phylink_link_state *state, u16 an_stat1)

{

	u16 lpa[3];

	int i, ret;



	ret = xpcs_read(xpcs, MDIO_MMD_AN, MDIO_STAT1);

	if (ret < 0)

		return ret;



	if (!(ret & MDIO_AN_STAT1_LPABLE)) {

	if (!(an_stat1 & MDIO_AN_STAT1_LPABLE)) {

		phylink_clear(state->lp_advertising, Autoneg);

		return 0;

	}
@@ -880,13 +854,25 @@ static int xpcs_get_state_c73(struct dw_xpcs *xpcs, 
			      const struct xpcs_compat *compat)

{

	bool an_enabled;

	int pcs_stat1;

	int an_stat1;

	int ret;



	/* The link status bit is latching-low, so it is important to

	 * avoid unnecessary re-reads of this register to avoid missing

	 * a link-down event.

	 */

	pcs_stat1 = xpcs_read(xpcs, MDIO_MMD_PCS, MDIO_STAT1);

	if (pcs_stat1 < 0) {

		state->link = false;

		return pcs_stat1;

	}



	/* Link needs to be read first ... */

	state->link = xpcs_read_link_c73(xpcs) > 0 ? 1 : 0;

	state->link = !!(pcs_stat1 & MDIO_STAT1_LSTATUS);



	/* ... and then we check the faults. */

	ret = xpcs_read_fault_c73(xpcs, state);

	ret = xpcs_read_fault_c73(xpcs, state, pcs_stat1);

	if (ret) {

		ret = xpcs_soft_reset(xpcs, compat);

		if (ret)
@@ -897,15 +883,38 @@ static int xpcs_get_state_c73(struct dw_xpcs *xpcs, 
		return xpcs_do_config(xpcs, state->interface, MLO_AN_INBAND, NULL);

	}



	/* There is no point doing anything else if the link is down. */

	if (!state->link)

		return 0;



	an_enabled = linkmode_test_bit(ETHTOOL_LINK_MODE_Autoneg_BIT,

				       state->advertising);

	if (an_enabled && xpcs_aneg_done_c73(xpcs, state, compat)) {

		state->an_complete = true;

		xpcs_read_lpa_c73(xpcs, state);

	if (an_enabled) {

		/* The link status bit is latching-low, so it is important to

		 * avoid unnecessary re-reads of this register to avoid missing

		 * a link-down event.

		 */

		an_stat1 = xpcs_read(xpcs, MDIO_MMD_AN, MDIO_STAT1);

		if (an_stat1 < 0) {

			state->link = false;

			return an_stat1;

		}



		state->an_complete = xpcs_aneg_done_c73(xpcs, state, compat,

							an_stat1);

		if (!state->an_complete) {

			state->link = false;

			return 0;

		}



		ret = xpcs_read_lpa_c73(xpcs, state, an_stat1);

		if (ret < 0) {

			state->link = false;

			return ret;

		}



		phylink_resolve_c73(state);

	} else if (an_enabled) {

		state->link = 0;

	} else if (state->link) {

	} else {

		xpcs_resolve_pma(xpcs, state);

	}