2023-11-28 08:50:55

by Maxime Chevallier

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Subject: [PATCH net] net: stmmac: dwmac-socfpga: Don't access SGMII adapter when not available

The SGMII adapter isn't present on all dwmac-socfpga implementations.
Make sure we don't try to configure it if we don't have this adapter.

Fixes: 5d1f3fe7d2d5 ("net: stmmac: dwmac-sogfpga: use the lynx pcs driver")
Signed-off-by: Maxime Chevallier <[email protected]>
---
drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
index ba2ce776bd4d..ae120792e1b6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
@@ -243,7 +243,8 @@ static void socfpga_sgmii_config(struct socfpga_dwmac *dwmac, bool enable)
{
u16 val = enable ? SGMII_ADAPTER_ENABLE : SGMII_ADAPTER_DISABLE;

- writew(val, dwmac->sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
+ if (dwmac->sgmii_adapter_base)
+ writew(val, dwmac->sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
}

static int socfpga_set_phy_mode_common(int phymode, u32 *val)
--
2.42.0


2023-11-28 09:19:07

by Thomas Petazzoni

[permalink] [raw]
Subject: Re: [PATCH net] net: stmmac: dwmac-socfpga: Don't access SGMII adapter when not available

On Tue, 28 Nov 2023 10:45:37 +0100
Maxime Chevallier <[email protected]> wrote:

> The SGMII adapter isn't present on all dwmac-socfpga implementations.
> Make sure we don't try to configure it if we don't have this adapter.
>
> Fixes: 5d1f3fe7d2d5 ("net: stmmac: dwmac-sogfpga: use the lynx pcs driver")
> Signed-off-by: Maxime Chevallier <[email protected]>
> ---
> drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> index ba2ce776bd4d..ae120792e1b6 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> @@ -243,7 +243,8 @@ static void socfpga_sgmii_config(struct socfpga_dwmac *dwmac, bool enable)
> {
> u16 val = enable ? SGMII_ADAPTER_ENABLE : SGMII_ADAPTER_DISABLE;
>
> - writew(val, dwmac->sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
> + if (dwmac->sgmii_adapter_base)
> + writew(val, dwmac->sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
> }
>
> static int socfpga_set_phy_mode_common(int phymode, u32 *val)

Reviewed-by: Thomas Petazzoni <[email protected]>

As a follow-up improvement, there's an open-coded version of
socfpga_sgmii_config() in socfpga_dwmac_fix_mac_speed(), which could be
rewritten as such:

socfpga_sgmii_config(dwmac, false);

if (splitter_base) {
val = readl(splitter_base + EMAC_SPLITTER_CTRL_REG);
val &= ~EMAC_SPLITTER_CTRL_SPEED_MASK;

switch (speed) {
case 1000:
val |= EMAC_SPLITTER_CTRL_SPEED_1000;
break;
case 100:
val |= EMAC_SPLITTER_CTRL_SPEED_100;
break;
case 10:
val |= EMAC_SPLITTER_CTRL_SPEED_10;
break;
default:
return;
}
writel(val, splitter_base + EMAC_SPLITTER_CTRL_REG);
}

if (phy_dev)
socfpga_sgmii_config(dwmac, true);

But of course, that's not a fix so it should be a separate improvement.

Best regards,

Thomas
--
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com

2023-11-28 09:26:55

by Maxime Chevallier

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Subject: Re: [PATCH net] net: stmmac: dwmac-socfpga: Don't access SGMII adapter when not available

Hello Thomas,

On Tue, 28 Nov 2023 10:18:41 +0100
Thomas Petazzoni <[email protected]> wrote:

> On Tue, 28 Nov 2023 10:45:37 +0100
> Maxime Chevallier <[email protected]> wrote:
>
> > The SGMII adapter isn't present on all dwmac-socfpga implementations.
> > Make sure we don't try to configure it if we don't have this adapter.
> >
> > Fixes: 5d1f3fe7d2d5 ("net: stmmac: dwmac-sogfpga: use the lynx pcs driver")
> > Signed-off-by: Maxime Chevallier <[email protected]>
> > ---
> > drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> > index ba2ce776bd4d..ae120792e1b6 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
> > @@ -243,7 +243,8 @@ static void socfpga_sgmii_config(struct socfpga_dwmac *dwmac, bool enable)
> > {
> > u16 val = enable ? SGMII_ADAPTER_ENABLE : SGMII_ADAPTER_DISABLE;
> >
> > - writew(val, dwmac->sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
> > + if (dwmac->sgmii_adapter_base)
> > + writew(val, dwmac->sgmii_adapter_base + SGMII_ADAPTER_CTRL_REG);
> > }
> >
> > static int socfpga_set_phy_mode_common(int phymode, u32 *val)
>
> Reviewed-by: Thomas Petazzoni <[email protected]>
>
> As a follow-up improvement, there's an open-coded version of
> socfpga_sgmii_config() in socfpga_dwmac_fix_mac_speed(), which could be
> rewritten as such:
>
> socfpga_sgmii_config(dwmac, false);
>
> if (splitter_base) {
> val = readl(splitter_base + EMAC_SPLITTER_CTRL_REG);
> val &= ~EMAC_SPLITTER_CTRL_SPEED_MASK;
[...]

I did saw this, but as this is merely a non-functional rework, I'd
like to target this to net-next, so I'll wait for the fix to land and
follow-up with this rework indeed.

Thanks for the review,

Maxime

2023-11-28 16:37:51

by Andrew Lunn

[permalink] [raw]
Subject: Re: [PATCH net] net: stmmac: dwmac-socfpga: Don't access SGMII adapter when not available

On Tue, Nov 28, 2023 at 10:45:37AM +0100, Maxime Chevallier wrote:
> The SGMII adapter isn't present on all dwmac-socfpga implementations.
> Make sure we don't try to configure it if we don't have this adapter.

If it does not exist, why even try to call socfpga_sgmii_config()?

It seems like this test needs moving up the call stack. socfpga_gen5_set_phy_mode():

if (phymode == PHY_INTERFACE_MODE_SGMII)
if (dwmac->sgmii_adapter_base)
socfpga_sgmii_config(dwmac, true);
else
return -EINVAL;

Same in socfpga_gen10_set_phy_mode()?

Andrew

2023-11-28 17:27:04

by Maxime Chevallier

[permalink] [raw]
Subject: Re: [PATCH net] net: stmmac: dwmac-socfpga: Don't access SGMII adapter when not available

Hi Andrew,

On Tue, 28 Nov 2023 17:37:30 +0100
Andrew Lunn <[email protected]> wrote:

> On Tue, Nov 28, 2023 at 10:45:37AM +0100, Maxime Chevallier wrote:
> > The SGMII adapter isn't present on all dwmac-socfpga implementations.
> > Make sure we don't try to configure it if we don't have this adapter.
>
> If it does not exist, why even try to call socfpga_sgmii_config()?
>
> It seems like this test needs moving up the call stack. socfpga_gen5_set_phy_mode():
>
> if (phymode == PHY_INTERFACE_MODE_SGMII)
> if (dwmac->sgmii_adapter_base)
> socfpga_sgmii_config(dwmac, true);
> else
> return -EINVAL;

I don't have access to a platform with the SGMII adapter available, but
my understanding is that we shouldn't error-out when we don't have the
adapter, as some other component (like the lynx PCS) might be there to
handle that mode.

However you have a valid point in that we might want to check if we
have either an SGMII adapter or a PCS, and if we have none of these we
error-out. Thanks for the suggestion, I'll address that :)

Maxime