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Message-ID: <20181114111104.GS30658@n2100.armlinux.org.uk>
Date: Wed, 14 Nov 2018 11:11:04 +0000
From: Russell King - ARM Linux <linux@...linux.org.uk>
To: Kishon Vijay Abraham I <kishon@...com>
Cc: devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
netdev@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
Gregory Clement <gregory.clement@...tlin.com>,
Jason Cooper <jason@...edaemon.net>,
Mark Rutland <mark.rutland@....com>,
Rob Herring <robh+dt@...nel.org>,
Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
Maxime Chevallier <maxime.chevallier@...tlin.com>
Subject: Re: [RFC PATCH 5/6] net: marvell: neta: add support for 2500base-X
On Wed, Nov 14, 2018 at 02:18:14PM +0530, Kishon Vijay Abraham I wrote:
> Hi,
>
> On 12/11/18 6:01 PM, Russell King wrote:
> > Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
> > ---
> > drivers/net/ethernet/marvell/mvneta.c | 58 ++++++++++++++++++++++++++++++-----
> > 1 file changed, 51 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> > index 5bfd349bf41a..7305d4cc0630 100644
> > --- a/drivers/net/ethernet/marvell/mvneta.c
> > +++ b/drivers/net/ethernet/marvell/mvneta.c
> > @@ -27,6 +27,7 @@
> > #include <linux/of_irq.h>
> > #include <linux/of_mdio.h>
> > #include <linux/of_net.h>
> > +#include <linux/phy/phy.h>
> > #include <linux/phy.h>
> > #include <linux/phylink.h>
> > #include <linux/platform_device.h>
> > @@ -437,6 +438,7 @@ struct mvneta_port {
> > struct device_node *dn;
> > unsigned int tx_csum_limit;
> > struct phylink *phylink;
> > + struct phy *comphy;
> >
> > struct mvneta_bm *bm_priv;
> > struct mvneta_bm_pool *pool_long;
> > @@ -3150,6 +3152,8 @@ static void mvneta_start_dev(struct mvneta_port *pp)
> > {
> > int cpu;
> >
> > + WARN_ON(phy_power_on(pp->comphy));
> > +
> > mvneta_max_rx_size_set(pp, pp->pkt_size);
> > mvneta_txq_max_tx_size_set(pp, pp->pkt_size);
> >
> > @@ -3212,6 +3216,8 @@ static void mvneta_stop_dev(struct mvneta_port *pp)
> >
> > mvneta_tx_reset(pp);
> > mvneta_rx_reset(pp);
> > +
> > + WARN_ON(phy_power_off(pp->comphy));
> > }
> >
> > static void mvneta_percpu_enable(void *arg)
> > @@ -3337,6 +3343,7 @@ static int mvneta_set_mac_addr(struct net_device *dev, void *addr)
> > static void mvneta_validate(struct net_device *ndev, unsigned long *supported,
> > struct phylink_link_state *state)
> > {
> > + struct mvneta_port *pp = netdev_priv(ndev);
> > __ETHTOOL_DECLARE_LINK_MODE_MASK(mask) = { 0, };
> >
> > /* We only support QSGMII, SGMII, 802.3z and RGMII modes */
> > @@ -3357,14 +3364,14 @@ static void mvneta_validate(struct net_device *ndev, unsigned long *supported,
> > /* Asymmetric pause is unsupported */
> > phylink_set(mask, Pause);
> >
> > - /* We cannot use 1Gbps when using the 2.5G interface. */
> > - if (state->interface == PHY_INTERFACE_MODE_2500BASEX) {
> > - phylink_set(mask, 2500baseT_Full);
> > - phylink_set(mask, 2500baseX_Full);
> > - } else {
> > + /* Half-duplex at speeds higher than 100Mbit is unsupported */
> > + if (pp->comphy || state->interface != PHY_INTERFACE_MODE_2500BASEX) {
> > phylink_set(mask, 1000baseT_Full);
> > phylink_set(mask, 1000baseX_Full);
> > }
> > + if (pp->comphy || state->interface == PHY_INTERFACE_MODE_2500BASEX) {
> > + phylink_set(mask, 2500baseX_Full);
> > + }
> >
> > if (!phy_interface_mode_is_8023z(state->interface)) {
> > /* 10M and 100M are only supported in non-802.3z mode */
> > @@ -3378,6 +3385,11 @@ static void mvneta_validate(struct net_device *ndev, unsigned long *supported,
> > __ETHTOOL_LINK_MODE_MASK_NBITS);
> > bitmap_and(state->advertising, state->advertising, mask,
> > __ETHTOOL_LINK_MODE_MASK_NBITS);
> > +
> > + /* We can only operate at 2500BaseX or 1000BaseX. If requested
> > + * to advertise both, only report advertising at 2500BaseX.
> > + */
> > + phylink_helper_basex_speed(state);
> > }
> >
> > static int mvneta_mac_link_state(struct net_device *ndev,
> > @@ -3389,7 +3401,9 @@ static int mvneta_mac_link_state(struct net_device *ndev,
> > gmac_stat = mvreg_read(pp, MVNETA_GMAC_STATUS);
> >
> > if (gmac_stat & MVNETA_GMAC_SPEED_1000)
> > - state->speed = SPEED_1000;
> > + state->speed =
> > + state->interface == PHY_INTERFACE_MODE_2500BASEX ?
> > + SPEED_2500 : SPEED_1000;
> > else if (gmac_stat & MVNETA_GMAC_SPEED_100)
> > state->speed = SPEED_100;
> > else
> > @@ -3504,12 +3518,32 @@ static void mvneta_mac_config(struct net_device *ndev, unsigned int mode,
> > MVNETA_GMAC_FORCE_LINK_DOWN);
> > }
> >
> > +
> > /* When at 2.5G, the link partner can send frames with shortened
> > * preambles.
> > */
> > if (state->speed == SPEED_2500)
> > new_ctrl4 |= MVNETA_GMAC4_SHORT_PREAMBLE_ENABLE;
> >
> > + if (pp->comphy) {
> > + enum phy_mode mode = PHY_MODE_INVALID;
> > +
> > + switch (state->interface) {
> > + case PHY_INTERFACE_MODE_SGMII:
> > + case PHY_INTERFACE_MODE_1000BASEX:
> > + mode = PHY_MODE_SGMII;
> > + break;
> > + case PHY_INTERFACE_MODE_2500BASEX:
> > + mode = PHY_MODE_2500SGMII;
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > + if (mode != PHY_MODE_INVALID)
> > + WARN_ON(phy_set_mode(pp->comphy, mode));
> > + }
> > +
> > if (new_ctrl0 != gmac_ctrl0)
> > mvreg_write(pp, MVNETA_GMAC_CTRL_0, new_ctrl0);
> > if (new_ctrl2 != gmac_ctrl2)
> > @@ -4411,7 +4445,7 @@ static int mvneta_port_power_up(struct mvneta_port *pp, int phy_mode)
> > if (phy_mode == PHY_INTERFACE_MODE_QSGMII)
> > mvreg_write(pp, MVNETA_SERDES_CFG, MVNETA_QSGMII_SERDES_PROTO);
> > else if (phy_mode == PHY_INTERFACE_MODE_SGMII ||
> > - phy_mode == PHY_INTERFACE_MODE_1000BASEX)
> > + phy_interface_mode_is_8023z(phy_mode))
> > mvreg_write(pp, MVNETA_SERDES_CFG, MVNETA_SGMII_SERDES_PROTO);
> > else if (!phy_interface_mode_is_rgmii(phy_mode))
> > return -EINVAL;
> > @@ -4428,6 +4462,7 @@ static int mvneta_probe(struct platform_device *pdev)
> > struct mvneta_port *pp;
> > struct net_device *dev;
> > struct phylink *phylink;
> > + struct phy *comphy;
> > const char *dt_mac_addr;
> > char hw_mac_addr[ETH_ALEN];
> > const char *mac_from;
> > @@ -4453,6 +4488,14 @@ static int mvneta_probe(struct platform_device *pdev)
> > goto err_free_irq;
> > }
> >
> > + comphy = devm_of_phy_get(&pdev->dev, dn, NULL);
> > + if (comphy == ERR_PTR(-EPROBE_DEFER)) {
> > + err = -EPROBE_DEFER;
> > + goto err_free_irq;
> > + } else if (IS_ERR(comphy)) {
> > + comphy = NULL;
> > + }
>
> devm_phy_optional_get can be used here instead.
I don't think that will work with a NULL string.
devm_phy_optional_get() ultimately ends up calling phy_get(), which
in this case would receive a NULL string. It will pass that NULL
string to of_property_match_string().
of_property_match_string() will try to find the "phy-names" property,
which will not exist, and hence will return -EINVAL.
phy_get() doesn't check for error conditions, but passes this directly
to _of_phy_get() as the index. _of_phy_get() passes that on to
of_parse_phandle_with_args(), which will fail to find an entry with
cur_index == -EINVAL (since it counts up from zero.) Hence,
_of_phy_get() will return -ENODEV, thereby causing
devm_phy_optional_get() to return NULL, even if there's a phys=
property present.
of_phy_get() and phy_get() have different behaviours when a NULL string
is passed in - the of_phy_get() family will get the first PHY specified
in the DT phys= property, whereas the phy_get() family of functions
will fail.
Since there is no devm_of_phy_optional_get(), that leads people down
the path of coding that functionality at the callsites, such as in
drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up
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