Re: [PATCH net] Revert "net: stmmac: platform: Fix MDIO init for platforms without PHY"
From: Robin Murphy
Date: Tue Jan 07 2020 - 07:36:28 EST
On 07/01/2020 12:14 pm, Sriram Dash wrote:
From: Robin Murphy <robin.murphy@xxxxxxx>
Subject: Re: [PATCH net] Revert "net: stmmac: platform: Fix MDIO init for
platforms without PHY"
On 07/01/2020 5:46 am, Sriram Dash wrote:
From: Florian Fainelli <f.fainelli@xxxxxxxxx>
Subject: [PATCH net] Revert "net: stmmac: platform: Fix MDIO init for
platforms
without PHY"
This reverts commit d3e014ec7d5ebe9644b5486bc530b91e62bbf624 ("net:
stmmac: platform: Fix MDIO init for platforms without PHY") because
it
breaks
existing systems with stmmac which do not have a MDIO bus sub-node
nor a 'phy-handle' property declared in their Device Tree. On those
systems, the stmmac MDIO bus is expected to be created and then
scanned by
of_mdiobus_register() to create PHY devices.
While these systems should arguably make use of a more accurate
Device
Tree
reprensentation with the use of the MDIO bus sub-node an appropriate
'phy- handle', we cannot break them, therefore restore the behavior
prior to the
said
commit.
Fixes: d3e014ec7d5e ("net: stmmac: platform: Fix MDIO init for
platforms without PHY")
Reported-by: Heiko Stuebner <heiko@xxxxxxxxx>
Reported-by: kernelci.org bot <bot@xxxxxxxxxxxx>
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Nacked-by: Sriram Dash <Sriram.dash@xxxxxxxxxxx>
---
Heiko,
I did not add the Tested-by because the patch is a little bit
different
from what
you tested, even if you most likely were not hitting the other part
that I
was
changing. Thanks!
drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index cc8d7e7bf9ac..bedaff0c13bd 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -320,7 +320,7 @@ static int stmmac_mtl_setup(struct
platform_device *pdev, static int stmmac_dt_phy(struct
plat_stmmacenet_data *plat,
struct device_node *np, struct device *dev) {
- bool mdio = false;
+ bool mdio = true;
This is breaking for the platforms with fixed-link.
stih418-b2199.dts and 169445.dts to name a few.
For the newer platforms, they should provide the mdio/ snps,dwmac-mdio
property in the device tree as we are checking the mdio/
snps,dwmac-mdio property in the stmmac_platform driver for the mdio bus
memory allocation.
For existing platforms, I agree we should not break them, but we
should make the code correct. And make the existing platforms adapt to the
proper code.
There is a proposed solution.
https://protect2.fireeye.com/url?k=d075c0fc-8da69942-d0744bb3-0cc47a31
ba82-60be9f5a0fb38a27&u=https://lkml.org/lkml/2020/1/7/14
What do you think?
The binding says that the phy handle and mdio child node are optional, so
"update all of the DTBs!" is not a viable solution. I'm far from an expert here, but
I get your point Robin. Because the mdio child or snps,dwmac-mdio is not mandatory,
there has been this problem.
AFAICS the fault of the current code is that it assumes the lack of a phy handle
implies a fixed link, so the obvious answer is to actually check whether the
Kind of.
"fixed-link" property is present.
I agree to have a fixed link check. Possibly this can be done:
FWIW, given the 4th case in the kerneldoc table I think this check might
need to come first. On the upside, there appears to be a handy helper
already, so it may just be as simple as:
bool mdio = !of_phy_is_fixed_link(np);
Robin.
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -320,7 +320,9 @@ static int stmmac_mtl_setup(struct platform_device *pdev,
static int stmmac_dt_phy(struct plat_stmmacenet_data *plat,
struct device_node *np, struct device *dev)
{
- bool mdio = false;
+ bool mdio = true;
+ struct device_node *fixed_link;
+
static const struct of_device_id need_mdio_ids[] = {
{ .compatible = "snps,dwc-qos-ethernet-4.10" },
{},
@@ -340,9 +342,8 @@ static int stmmac_dt_phy(struct plat_stmmacenet_data *plat,
}
}
- if (plat->mdio_node) {
- dev_dbg(dev, "Found MDIO subnode\n");
- mdio = true;
+ if (of_get_child_by_name(np, "fixed-link")) {
+ mdio = false;
}
if (mdio) {
Neil and Heiko,
Can you guys please test this on your platforms?
We can post a more cleaner version of the patch if all agree to it.
Robin.
static const struct of_device_id need_mdio_ids[] = {
{ .compatible = "snps,dwc-qos-ethernet-4.10" },
{},
--
2.19.1
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