Date:	Fri, 10 Oct 2014 12:46:38 -0700
From:	Petri Gynther <pgynther@...gle.com>
To:	Florian Fainelli <f.fainelli@...il.com>
Cc:	netdev@...r.kernel.org, David Miller <davem@...emloft.net>
Subject: Re: [PATCH net-next] net: bcmgenet: enable driver to work without a
 device tree

Hi Florian,

On Fri, Oct 10, 2014 at 11:59 AM, Florian Fainelli <f.fainelli@...il.com> wrote:
> On 10/10/2014 11:35 AM, Petri Gynther wrote:
>> Broadcom 7xxx MIPS-based STB platforms do not use device trees.
>> Modify bcmgenet driver so that it can be used on those platforms.
>>
>> Signed-off-by: Petri Gynther <pgynther@...gle.com>
>> ---
>
> [snip]
>
>> diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.h b/drivers/net/ethernet/broadcom/genet/bcmgenet.h
>> index dbf524e..5191e3f 100644
>> --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.h
>> +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.h
>> @@ -17,6 +17,17 @@
>>  #include <linux/if_vlan.h>
>>  #include <linux/phy.h>
>>
>> +struct bcmgenet_platform_data {
>> +     void __iomem    *base_reg;
>> +     int             irq0;
>> +     int             irq1;
>
> Why would these members here? The platform device should provide those
> as standard resources that the driver fetches using
> platform_get_resource() and platform_get_irq().
>

I modeled this on struct bcmemac_platform_data that was used in the
legacy BRCMSTB code.
include/linux/brcmstb/brcmstb.h:

struct bcmemac_platform_data {
        /* used by the BSP code only */
        uintptr_t               base_reg;
        int                     irq0;
        int                     irq1;

        int                     phy_type;
        int                     phy_id;
        int                     phy_speed;
        u8                      macaddr[ETH_ALEN];
};

The legacy BRCMSTB code stores all relevant GENET info in this struct
and then creates the resources from that info:

static void __init brcm_register_genet(int id, struct bcmemac_platform_data *pd)
{
        struct resource res[3];
        struct platform_device *pdev;

        memset(&res, 0, sizeof(res));
        res[0].start = BPHYSADDR(pd->base_reg);
        res[0].end = BPHYSADDR(pd->base_reg + 0x4fff);
        res[0].flags = IORESOURCE_MEM;

        res[1].start = res[1].end = pd->irq0;
        res[1].flags = IORESOURCE_IRQ;

        res[2].start = res[2].end = pd->irq1;
        res[2].flags = IORESOURCE_IRQ;

        brcm_alloc_macaddr(pd->macaddr);

        pdev = platform_device_alloc("bcmgenet", id);
        platform_device_add_resources(pdev, res, 3);
        platform_device_add_data(pdev, pd, sizeof(*pd));
        platform_device_add(pdev);
}

>> +     int             phy_type;
>> +     int             phy_addr;
>> +     int             phy_speed;
>> +     u8              macaddr[ETH_ALEN];
>> +     int             genet_version;
>> +};
>
> I would rather we put this in include/linux/platform_data/bcmgenet.h
> where it belongs.
>

I wasn't aware of the directory include/linux/platform_data/. Yes,
that's where this belongs.

>> +
>>  /* total number of Buffer Descriptors, same for Rx/Tx */
>>  #define TOTAL_DESC                           256
>>
>> diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
>> index 9ff799a..e5ff913 100644
>> --- a/drivers/net/ethernet/broadcom/genet/bcmmii.c
>> +++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c
>> @@ -157,6 +157,21 @@ static void bcmgenet_mii_setup(struct net_device *dev)
>>       phy_print_status(phydev);
>>  }
>>
>> +static int bcmgenet_moca_fphy_update(struct net_device *dev,
>> +                                  struct fixed_phy_status *status)
>> +{
>> +     struct bcmgenet_priv *priv = netdev_priv(dev);
>> +     struct phy_device *phydev = priv->phydev;
>> +
>> +     /*
>> +      * MoCA daemon updates phydev->autoneg to reflect the link status.
>> +      * Update MoCA fixed PHY status accordingly, so that the PHY state
>> +      * machine becomes aware of the real link status.
>> +      */
>> +     status->link = phydev->autoneg;
>> +     return 0;
>> +}
>
> I don't want to see that in the upstream driver, please enable the link
> interrupts like I suggested before and do not use the autoneg field at
> all, which should require no MoCA daemon modifications.
>

I added debug printk's to bcmgenet_isr0 to check on UMAC_IRQ_LINK_UP
and UMAC_IRQ_LINK_DOWN.
I am not getting those interrupts on eth1 (MoCA) port when coax is
removed/inserted.
But, they do work on eth0.

I'll modify init_umac() to enable those interrupts for MoCA port and retest.

> [snip]
>
>>
>>       priv->phydev = phydev;
>> @@ -437,6 +464,104 @@ static int bcmgenet_mii_of_init(struct bcmgenet_priv *priv)
>>       return 0;
>>  }
>>
>> +static int bcmgenet_mii_pd_init(struct bcmgenet_priv *priv)
>> +{
>> +     struct device *kdev = &priv->pdev->dev;
>> +     struct bcmgenet_platform_data *pd = kdev->platform_data;
>> +     struct mii_bus *mdio = priv->mii_bus;
>> +     int phy_addr = pd->phy_addr;
>> +     struct phy_device *phydev;
>> +     int ret;
>> +     int i;
>> +
>> +     /* Disable automatic MDIO bus scan */
>> +     mdio->phy_mask = ~0;
>> +
>> +     /* Clear all the IRQ properties */
>> +     if (mdio->irq)
>> +             for (i = 0; i < PHY_MAX_ADDR; i++)
>> +                     mdio->irq[i] = PHY_POLL;
>> +
>> +     /* Register the MDIO bus */
>> +     ret = mdiobus_register(mdio);
>> +     if (ret) {
>> +             dev_err(kdev, "failed to register MDIO bus\n");
>> +             return ret;
>> +     }
>> +
>> +     /*
>> +      * bcmgenet_platform_data needs to pass a valid PHY address for
>> +      * internal/external PHY or -1 for MoCA PHY.
>> +      */
>> +     if (phy_addr >= 0 && phy_addr < PHY_MAX_ADDR) {
>
> We do too much low-level PHY device handling, and since you already have
> the phy_type provided via platform_data, we can use that hint to do the
> following:
>
> 1) an internal or external PHY with MDIO accesses should leave the bus
> auto-probing on with the specified PHY address in the mdio bus phy_mask
>
> 2) a MoCA PHY or an external PHY with MDIO accesses disabled should use
> the fixed-0 MII bus instead.
>
> This would look like this:
>
> if (pd->phy_type != PHY_INTERFACE_MODE_MOCA || pd->mdio_enabled)
>         mdio->phy_mask = ~(1 << pd->phy_addr);
>
>         ...
>         mdiobus_register()
>
>         priv->phydev = mdio->bus->phy_map[pd->phy_addr];
>
>         phydev->phy_flags |= mask;
>
> if (pd->phy_type == PHY_INTERFACE_MODE_MOCA || !pd->mdio_enabled)
>         priv->phydev = fixed_phy_register(...);
>
> and in both cases, later on you do connect to the PHY device
>
> I can cook a patch to illustrate what I think this could look like since
> I realize using pseudo-code to explain might not be the best thing.
>

I think I understand what you mean. I'll make a change.

>> +             /*
>> +              * 10/100/1000 Ethernet port with external or internal PHY.
>> +              */
>> +             phydev = get_phy_device(mdio, phy_addr, false);
>> +             if (!phydev || IS_ERR(phydev)) {
>> +                     dev_err(kdev, "failed to create PHY device\n");
>> +                     mdiobus_unregister(mdio);
>> +                     return 1;
>> +             }
>> +
>> +             phydev->irq = PHY_POLL;
>> +
>> +             ret = phy_device_register(phydev);
>> +             if (ret) {
>> +                     dev_err(kdev, "failed to register PHY device\n");
>> +                     phy_device_free(phydev);
>> +                     mdiobus_unregister(mdio);
>> +                     return 1;
>> +             }
>> +
>> +             priv->phydev = phydev;
>> +             priv->phy_interface = pd->phy_type;
>> +     } else {
>> +             /*
>> +              * MoCA port with no MDIO-accessible PHY.
>> +              * We need to use 1000/HD fixed PHY to represent the link layer.
>> +              * MoCA daemon interacts with this PHY via ethtool.
>> +              */
>> +             struct fixed_phy_status moca_fphy_status = {
>> +                     .link = 0,
>> +                     .duplex = 0,
>
> This should be DUPLEX_FULL here, the link between GENET and the MoCA
> Ethernet convergence layer is full-duplex by nature (despite we report
> the PHY being half-duplex, which is a mistake in the downstream driver),
> the MoCA medium on the coaxial cable is half-duplex though, but that is
> handled by the MoCA HW.
>
> NB: I had issues in the past using a half-duplex link with the MoCA
> ethernet convergence layer, causing various types of packet loss because
> we use a simplified signaling internally in the hardware.
>

I picked this setting from 3.3 GENET driver. I'll test 1000/FULL on my
platform to see if it works.

>> +                     .speed = 1000,
>> +                     .pause = 0,
>> +                     .asym_pause = 0,
>> +             };
>> +
>> +             phydev = fixed_phy_register(PHY_POLL, &moca_fphy_status, NULL);
>> +             if (!phydev || IS_ERR(phydev)) {
>> +                     dev_err(kdev, "failed to register fixed PHY device\n");
>> +                     mdiobus_unregister(mdio);
>> +                     return 1;
>> +             }
>> +
>> +             phydev->autoneg = AUTONEG_DISABLE;
>> +
>> +             ret = fixed_phy_set_link_update(phydev,
>> +                                             bcmgenet_moca_fphy_update);
>> +             if (ret) {
>> +                     dev_err(kdev, "failed to set fixed PHY link update\n");
>> +             }
>
> Should not we propagate this error to the caller?

Good catch. Yes.

> --
> Florian
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