Re: [PATCH v2 2/5] net: macb: add support for sgmii MAC-PHY interface

From: Russell King - ARM Linux admin
Date: Wed Jun 19 2019 - 05:37:06 EST

On Wed, Jun 19, 2019 at 09:40:46AM +0100, Parshuram Thombare wrote:
> This patch add support for SGMII interface) and
> 2.5Gbps MAC in Cadence ethernet controller driver.
>
> Signed-off-by: Parshuram Thombare <pthombar@xxxxxxxxxxx>
> ---
> drivers/net/ethernet/cadence/macb.h | 76 ++++++++++--
> drivers/net/ethernet/cadence/macb_main.c | 151 ++++++++++++++++++++---
> 2 files changed, 200 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
> index 35ed13236c8b..d7ffbfb2ecc0 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -80,6 +80,7 @@
> #define MACB_RBQPH 0x04D4
>
> /* GEM register offsets. */
> +#define GEM_NCR 0x0000 /* Network Control */
> #define GEM_NCFGR 0x0004 /* Network Config */
> #define GEM_USRIO 0x000c /* User IO */
> #define GEM_DMACFG 0x0010 /* DMA Configuration */
> @@ -159,6 +160,9 @@
> #define GEM_PEFTN 0x01f4 /* PTP Peer Event Frame Tx Ns */
> #define GEM_PEFRSL 0x01f8 /* PTP Peer Event Frame Rx Sec Low */
> #define GEM_PEFRN 0x01fc /* PTP Peer Event Frame Rx Ns */
> +#define GEM_PCS_CTRL 0x0200 /* PCS Control */
> +#define GEM_PCS_STATUS 0x0204 /* PCS Status */
> +#define GEM_PCS_AN_LP_BASE 0x0214 /* PCS AN LP BASE*/
> #define GEM_DCFG1 0x0280 /* Design Config 1 */
> #define GEM_DCFG2 0x0284 /* Design Config 2 */
> #define GEM_DCFG3 0x0288 /* Design Config 3 */
> @@ -274,6 +278,10 @@
> #define MACB_IRXFCS_OFFSET 19
> #define MACB_IRXFCS_SIZE 1
>
> +/* GEM specific NCR bitfields. */
> +#define GEM_TWO_PT_FIVE_GIG_OFFSET 29
> +#define GEM_TWO_PT_FIVE_GIG_SIZE 1
> +
> /* GEM specific NCFGR bitfields. */
> #define GEM_GBE_OFFSET 10 /* Gigabit mode enable */
> #define GEM_GBE_SIZE 1
> @@ -326,6 +334,9 @@
> #define MACB_MDIO_SIZE 1
> #define MACB_IDLE_OFFSET 2 /* The PHY management logic is idle */
> #define MACB_IDLE_SIZE 1
> +#define MACB_DUPLEX_OFFSET 3
> +#define MACB_DUPLEX_SIZE 1
> +
>
> /* Bitfields in TSR */
> #define MACB_UBR_OFFSET 0 /* Used bit read */
> @@ -459,11 +470,37 @@
> #define MACB_REV_OFFSET 0
> #define MACB_REV_SIZE 16
>
> +/* Bitfields in PCS_CONTROL. */
> +#define GEM_PCS_CTRL_RST_OFFSET 15
> +#define GEM_PCS_CTRL_RST_SIZE 1
> +#define GEM_PCS_CTRL_EN_AN_OFFSET 12
> +#define GEM_PCS_CTRL_EN_AN_SIZE 1
> +#define GEM_PCS_CTRL_RESTART_AN_OFFSET 9
> +#define GEM_PCS_CTRL_RESTART_AN_SIZE 1
> +
> +/* Bitfields in PCS_STATUS. */
> +#define GEM_PCS_STATUS_AN_DONE_OFFSET 5
> +#define GEM_PCS_STATUS_AN_DONE_SIZE 1
> +#define GEM_PCS_STATUS_AN_SUPPORT_OFFSET 3
> +#define GEM_PCS_STATUS_AN_SUPPORT_SIZE 1
> +#define GEM_PCS_STATUS_LINK_OFFSET 2
> +#define GEM_PCS_STATUS_LINK_SIZE 1
> +
> +/* Bitfield in PCS_AN_LP_BASE */
> +#define GEM_PCS_AN_LP_BASE_LINK_OFFSET 15
> +#define GEM_PCS_AN_LP_BASE_LINK_SIZE 1
> +#define GEM_PCS_AN_LP_BASE_DUPLEX_OFFSET 12
> +#define GEM_PCS_AN_LP_BASE_DUPLEX_SIZE 1
> +#define GEM_PCS_AN_LP_BASE_SPEED_OFFSET 10
> +#define GEM_PCS_AN_LP_BASE_SPEED_SIZE 2
> +
> /* Bitfields in DCFG1. */
> #define GEM_IRQCOR_OFFSET 23
> #define GEM_IRQCOR_SIZE 1
> #define GEM_DBWDEF_OFFSET 25
> #define GEM_DBWDEF_SIZE 3
> +#define GEM_NO_PCS_OFFSET 0
> +#define GEM_NO_PCS_SIZE 1
>
> /* Bitfields in DCFG2. */
> #define GEM_RX_PKT_BUFF_OFFSET 20
> @@ -636,19 +673,32 @@
> #define MACB_MAN_CODE 2
>
> /* Capability mask bits */
> -#define MACB_CAPS_ISR_CLEAR_ON_WRITE 0x00000001
> -#define MACB_CAPS_USRIO_HAS_CLKEN 0x00000002
> -#define MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII 0x00000004
> -#define MACB_CAPS_NO_GIGABIT_HALF 0x00000008
> -#define MACB_CAPS_USRIO_DISABLED 0x00000010
> -#define MACB_CAPS_JUMBO 0x00000020
> -#define MACB_CAPS_GEM_HAS_PTP 0x00000040
> -#define MACB_CAPS_BD_RD_PREFETCH 0x00000080
> -#define MACB_CAPS_NEEDS_RSTONUBR 0x00000100
> -#define MACB_CAPS_FIFO_MODE 0x10000000
> -#define MACB_CAPS_GIGABIT_MODE_AVAILABLE 0x20000000
> -#define MACB_CAPS_SG_DISABLED 0x40000000
> -#define MACB_CAPS_MACB_IS_GEM 0x80000000
> +#define MACB_CAPS_ISR_CLEAR_ON_WRITE BIT(0)
> +#define MACB_CAPS_USRIO_HAS_CLKEN BIT(1)
> +#define MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII BIT(2)
> +#define MACB_CAPS_NO_GIGABIT_HALF BIT(3)
> +#define MACB_CAPS_USRIO_DISABLED BIT(4)
> +#define MACB_CAPS_JUMBO BIT(5)
> +#define MACB_CAPS_GEM_HAS_PTP BIT(6)
> +#define MACB_CAPS_BD_RD_PREFETCH BIT(7)
> +#define MACB_CAPS_NEEDS_RSTONUBR BIT(8)
> +#define MACB_CAPS_FIFO_MODE BIT(28)
> +#define MACB_CAPS_GIGABIT_MODE_AVAILABLE BIT(29)
> +#define MACB_CAPS_SG_DISABLED BIT(30)
> +#define MACB_CAPS_MACB_IS_GEM BIT(31)
> +#define MACB_CAPS_PCS BIT(24)
> +#define MACB_CAPS_MACB_IS_GEM_GXL BIT(25)
> +
> +#define MACB_GEM7010_IDNUM 0x009
> +#define MACB_GEM7014_IDNU 0x107
> +#define MACB_GEM7014A_IDNUM 0x207
> +#define MACB_GEM7016_IDNUM 0x10a
> +#define MACB_GEM7017_IDNUM 0x00a
> +#define MACB_GEM7017A_IDNUM 0x20a
> +#define MACB_GEM7020_IDNUM 0x003
> +#define MACB_GEM7021_IDNUM 0x00c
> +#define MACB_GEM7021A_IDNUM 0x20c
> +#define MACB_GEM7022_IDNUM 0x00b
>
> /* LSO settings */
> #define MACB_LSO_UFO_ENABLE 0x01
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 830af86d3c65..884d2a4408ad 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -403,6 +403,7 @@ static int macb_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
> */
> static void macb_set_tx_clk(struct clk *clk, int speed, struct net_device *dev)
> {
> + struct macb *bp = netdev_priv(dev);
> long ferr, rate, rate_rounded;
>
> if (!clk)
> @@ -418,6 +419,12 @@ static void macb_set_tx_clk(struct clk *clk, int speed, struct net_device *dev)
> case SPEED_1000:
> rate = 125000000;
> break;
> + case SPEED_2500:
> + if (bp->caps & MACB_CAPS_MACB_IS_GEM_GXL)
> + rate = 312500000;
> + else
> + rate = 125000000;
> + break;
> default:
> return;
> }
> @@ -448,15 +455,16 @@ static void gem_phylink_validate(struct phylink_config *pl_config,
> __ETHTOOL_DECLARE_LINK_MODE_MASK(mask) = { 0, };
>
> switch (state->interface) {
> + case PHY_INTERFACE_MODE_SGMII:
> + if (bp->caps & MACB_CAPS_GIGABIT_MODE_AVAILABLE)
> + phylink_set(mask, 2500baseT_Full);

This doesn't look correct to me. SGMII as defined by Cisco only
supports 1G, 100M and 10M speeds, not 2.5G.

Even so, SGMII is not limited to just base-T - PHYs are free to offer
base-X to SGMII conversion too.

> + /* fallthrough */
> case PHY_INTERFACE_MODE_GMII:
> case PHY_INTERFACE_MODE_RGMII:
> if (bp->caps & MACB_CAPS_GIGABIT_MODE_AVAILABLE) {
> phylink_set(mask, 1000baseT_Full);
> - phylink_set(mask, 1000baseX_Full);
> - if (!(bp->caps & MACB_CAPS_NO_GIGABIT_HALF)) {
> - phylink_set(mask, 1000baseT_Half);
> + if (!(bp->caps & MACB_CAPS_NO_GIGABIT_HALF))
> phylink_set(mask, 1000baseT_Half);
> - }
> }
> /* fallthrough */
> case PHY_INTERFACE_MODE_MII:
> @@ -466,6 +474,16 @@ static void gem_phylink_validate(struct phylink_config *pl_config,
> phylink_set(mask, 100baseT_Half);
> phylink_set(mask, 100baseT_Full);
> break;
> +
> + case PHY_INTERFACE_MODE_2500BASEX:
> + if (bp->caps & MACB_CAPS_GIGABIT_MODE_AVAILABLE)
> + phylink_set(mask, 2500baseX_Full);
> + /* fallthrough */
> + case PHY_INTERFACE_MODE_1000BASEX:
> + if (bp->caps & MACB_CAPS_GIGABIT_MODE_AVAILABLE)
> + phylink_set(mask, 1000baseX_Full);
> + break;

Please see how other drivers which use phylink deal with the validate()
format, and please read the phylink documentation:

* Note that the PHY may be able to transform from one connection
* technology to another, so, eg, don't clear 1000BaseX just
* because the MAC is unable to BaseX mode. This is more about
* clearing unsupported speeds and duplex settings.

> +
> default:
> break;
> }
> @@ -480,13 +498,52 @@ static int gem_phylink_mac_link_state(struct phylink_config *pl_config,
> {
> struct net_device *netdev = to_net_dev(pl_config->dev);
> struct macb *bp = netdev_priv(netdev);
> + u32 status;
>
> - state->speed = bp->speed;
> - state->duplex = bp->duplex;
> - state->link = bp->link;
> + if (bp->phy_interface == PHY_INTERFACE_MODE_SGMII) {
> + status = gem_readl(bp, PCS_STATUS);
> + state->an_complete = GEM_BFEXT(PCS_STATUS_AN_DONE, status);
> + status = gem_readl(bp, PCS_AN_LP_BASE);
> + switch (GEM_BFEXT(PCS_AN_LP_BASE_SPEED, status)) {
> + case 0:
> + state->speed = SPEED_10;
> + break;
> + case 1:
> + state->speed = SPEED_100;
> + break;
> + case 2:
> + state->speed = SPEED_1000;
> + break;
> + default:
> + break;
> + }
> + state->duplex = MACB_BFEXT(DUPLEX, macb_readl(bp, NSR));
> + state->link = MACB_BFEXT(NSR_LINK, macb_readl(bp, NSR));
> + } else if (bp->phy_interface == PHY_INTERFACE_MODE_2500BASEX) {
> + state->speed = SPEED_2500;
> + state->duplex = MACB_BFEXT(DUPLEX, macb_readl(bp, NSR));
> + state->link = MACB_BFEXT(NSR_LINK, macb_readl(bp, NSR));
> + } else if (bp->phy_interface == PHY_INTERFACE_MODE_1000BASEX) {
> + state->speed = SPEED_1000;
> + state->duplex = MACB_BFEXT(DUPLEX, macb_readl(bp, NSR));
> + state->link = MACB_BFEXT(NSR_LINK, macb_readl(bp, NSR));
> + }

So if the phy_interface type is not one listed, we leave state alone?
That doesn't seem good. It looks like you should at least simply set
state->duplex and state->link according to the NSR register content,
and always derive the speed.

It would also be good to set state->lp_advertising if you have access
to that so ethtool can report the link partner's abilities. Current
Marvell drivers that use phylink don't do that because that information
is not available from the hardware.

> return 1;
> }
>
> +static void gem_mac_an_restart(struct phylink_config *pl_config)
> +{
> + struct net_device *netdev = to_net_dev(pl_config->dev);
> + struct macb *bp = netdev_priv(netdev);
> +
> + if (bp->phy_interface == PHY_INTERFACE_MODE_SGMII ||
> + bp->phy_interface == PHY_INTERFACE_MODE_1000BASEX ||
> + bp->phy_interface == PHY_INTERFACE_MODE_2500BASEX) {
> + gem_writel(bp, PCS_CTRL, gem_readl(bp, PCS_CTRL) |
> + GEM_BIT(PCS_CTRL_RESTART_AN));
> + }

This will only be called for 802.3z link modes, so you don't need these
checks.

> +}
> +
> static void gem_mac_config(struct phylink_config *pl_config, unsigned int mode,
> const struct phylink_link_state *state)
> {
> @@ -506,18 +563,26 @@ static void gem_mac_config(struct phylink_config *pl_config, unsigned int mode,
> reg &= ~GEM_BIT(GBE);
> if (state->duplex)
> reg |= MACB_BIT(FD);
> + macb_or_gem_writel(bp, NCFGR, reg);
>
> switch (state->speed) {
> + case SPEED_2500:
> + gem_writel(bp, NCFGR, GEM_BIT(GBE) |
> + gem_readl(bp, NCFGR));
> + gem_writel(bp, NCR, GEM_BIT(TWO_PT_FIVE_GIG) |
> + gem_readl(bp, NCR));
> + break;
> case SPEED_1000:
> - reg |= GEM_BIT(GBE);
> + gem_writel(bp, NCFGR, GEM_BIT(GBE) |
> + gem_readl(bp, NCFGR));
> break;
> case SPEED_100:
> - reg |= MACB_BIT(SPD);
> + macb_writel(bp, NCFGR, MACB_BIT(SPD) |
> + macb_readl(bp, NCFGR));
> break;
> default:
> break;
> }
> - macb_or_gem_writel(bp, NCFGR, reg);
>
> bp->speed = state->speed;
> bp->duplex = state->duplex;

This is not going to work for 802.3z nor SGMII properly when in-band
negotiation is used. We don't know ahead of time what the speed and
duplex will be. Please see existing drivers for examples showing
how mac_config() should be implemented (there's good reason why its
laid out as it is in those drivers.)

> @@ -555,6 +620,7 @@ static void gem_mac_link_down(struct phylink_config *pl_config,
> static const struct phylink_mac_ops gem_phylink_ops = {
> .validate = gem_phylink_validate,
> .mac_link_state = gem_phylink_mac_link_state,
> + .mac_an_restart = gem_mac_an_restart,
> .mac_config = gem_mac_config,
> .mac_link_up = gem_mac_link_up,
> .mac_link_down = gem_mac_link_down,
> @@ -2248,7 +2314,9 @@ static void macb_init_hw(struct macb *bp)
> macb_set_hwaddr(bp);
>
> config = macb_mdc_clk_div(bp);
> - if (bp->phy_interface == PHY_INTERFACE_MODE_SGMII)
> + if (bp->phy_interface == PHY_INTERFACE_MODE_SGMII ||
> + bp->phy_interface == PHY_INTERFACE_MODE_1000BASEX ||
> + bp->phy_interface == PHY_INTERFACE_MODE_2500BASEX)
> config |= GEM_BIT(SGMIIEN) | GEM_BIT(PCSSEL);

Configuration of the phy interface mode should be done in mac_config()
as previously mentioned, some PHYs can change their link mode at run
time. Hotplugging SFPs can change the link mode between SGMII and
base-X too.

> config |= MACB_BF(RBOF, NET_IP_ALIGN); /* Make eth data aligned */
> config |= MACB_BIT(PAE); /* PAuse Enable */
> @@ -2273,6 +2341,17 @@ static void macb_init_hw(struct macb *bp)
> if (bp->caps & MACB_CAPS_JUMBO)
> bp->rx_frm_len_mask = MACB_RX_JFRMLEN_MASK;
>
> + if (bp->phy_interface == PHY_INTERFACE_MODE_SGMII ||
> + bp->phy_interface == PHY_INTERFACE_MODE_1000BASEX ||
> + bp->phy_interface == PHY_INTERFACE_MODE_2500BASEX) {
> + //Enable PCS AN
> + gem_writel(bp, PCS_CTRL, gem_readl(bp, PCS_CTRL) |
> + GEM_BIT(PCS_CTRL_EN_AN));
> + //Reset PCS block
> + gem_writel(bp, PCS_CTRL, gem_readl(bp, PCS_CTRL) |
> + GEM_BIT(PCS_CTRL_RST));
> + }
> +

Should be in mac_config.

> macb_configure_dma(bp);
>
> /* Initialize TX and RX buffers */
> @@ -3364,6 +3443,22 @@ static void macb_configure_caps(struct macb *bp,
> dcfg = gem_readl(bp, DCFG1);
> if (GEM_BFEXT(IRQCOR, dcfg) == 0)
> bp->caps |= MACB_CAPS_ISR_CLEAR_ON_WRITE;
> + if (GEM_BFEXT(NO_PCS, dcfg) == 0)
> + bp->caps |= MACB_CAPS_PCS;
> + switch (MACB_BFEXT(IDNUM, macb_readl(bp, MID))) {
> + case MACB_GEM7016_IDNUM:
> + case MACB_GEM7017_IDNUM:
> + case MACB_GEM7017A_IDNUM:
> + case MACB_GEM7020_IDNUM:
> + case MACB_GEM7021_IDNUM:
> + case MACB_GEM7021A_IDNUM:
> + case MACB_GEM7022_IDNUM:
> + bp->caps |= MACB_CAPS_USRIO_DISABLED;
> + bp->caps |= MACB_CAPS_MACB_IS_GEM_GXL;
> + break;
> + default:
> + break;
> + }
> dcfg = gem_readl(bp, DCFG2);
> if ((dcfg & (GEM_BIT(RX_PKT_BUFF) | GEM_BIT(TX_PKT_BUFF))) == 0)
> bp->caps |= MACB_CAPS_FIFO_MODE;
> @@ -3652,7 +3747,9 @@ static int macb_init(struct platform_device *pdev)
> /* Set MII management clock divider */
> val = macb_mdc_clk_div(bp);
> val |= macb_dbw(bp);
> - if (bp->phy_interface == PHY_INTERFACE_MODE_SGMII)
> + if (bp->phy_interface == PHY_INTERFACE_MODE_SGMII ||
> + bp->phy_interface == PHY_INTERFACE_MODE_1000BASEX ||
> + bp->phy_interface == PHY_INTERFACE_MODE_2500BASEX)
> val |= GEM_BIT(SGMIIEN) | GEM_BIT(PCSSEL);

Should be in mac_config.

> macb_writel(bp, NCFGR, val);
>
> @@ -4346,11 +4443,37 @@ static int macb_probe(struct platform_device *pdev)
> }
>
> phy_mode = of_get_phy_mode(np);
> - if (phy_mode < 0)
> + if (phy_mode < 0) {
> /* not found in DT, MII by default */
> bp->phy_interface = PHY_INTERFACE_MODE_MII;
> - else
> + } else if (bp->caps & MACB_CAPS_MACB_IS_GEM_GXL) {
> + u32 interface_supported = 1;
> +
> + if (phy_mode == PHY_INTERFACE_MODE_SGMII ||
> + phy_mode == PHY_INTERFACE_MODE_1000BASEX ||
> + phy_mode == PHY_INTERFACE_MODE_2500BASEX) {
> + if (!(bp->caps & MACB_CAPS_PCS))
> + interface_supported = 0;
> + } else if (phy_mode == PHY_INTERFACE_MODE_GMII ||
> + phy_mode == PHY_INTERFACE_MODE_RGMII) {
> + if (!macb_is_gem(bp))
> + interface_supported = 0;
> + } else if (phy_mode != PHY_INTERFACE_MODE_RMII &&
> + phy_mode != PHY_INTERFACE_MODE_MII) {
> + /* Add new mode before this */
> + interface_supported = 0;
> + }
> +
> + if (!interface_supported) {
> + netdev_err(dev, "Phy mode %s not supported",
> + phy_modes(phy_mode));
> + goto err_out_free_netdev;
> + }
> +
> bp->phy_interface = phy_mode;
> + } else {
> + bp->phy_interface = phy_mode;
> + }
>
> /* IP specific init */
> err = init(pdev);
> --
> 2.17.1
>
>

--
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