Re: [PATCH] net: stmmac: platform: Fix MDIO init for platforms without PHY

[Florian Fainelli <f.fainelli@gmail.com>]

On 1/5/20 3:05 PM, Heiko Stübner wrote:
> Hi Florian,
> 
> Am Sonntag, 5. Januar 2020, 23:22:00 CET schrieb Florian Fainelli:
>> On 1/5/2020 12:43 PM, Heiko Stübner wrote:
>>> Am Samstag, 21. Dezember 2019, 06:29:18 CET schrieb David Miller:
>>>> From: Padmanabhan Rajanbabu <p.rajanbabu@samsung.com>
>>>> Date: Thu, 19 Dec 2019 15:47:01 +0530
>>>>
>>>>> The current implementation of "stmmac_dt_phy" function initializes
>>>>> the MDIO platform bus data, even in the absence of PHY. This fix
>>>>> will skip MDIO initialization if there is no PHY present.
>>>>>
>>>>> Fixes: 7437127 ("net: stmmac: Convert to phylink and remove phylib logic")
>>>>> Acked-by: Jayati Sahu <jayati.sahu@samsung.com>
>>>>> Signed-off-by: Sriram Dash <sriram.dash@samsung.com>
>>>>> Signed-off-by: Padmanabhan Rajanbabu <p.rajanbabu@samsung.com>
>>>>
>>>> Applied and queued up for -stable, thanks.
>>>
>>> with this patch applied I now run into issues on multiple rockchip
>>> platforms using a gmac interface.
>>
>> Do you have a list of DTS files that are affected by any chance? For the
>> 32-bit platforms that I looked it, it seems like:
>>
>> arch/arm/boot/dts/rk3228-evb.dts is OK because it has a MDIO bus node
>> arch/arm/boot/dts/rk3229-xms6.dts is also OK
>>
>> arch/arm/boot/dts/rk3229-evb.dts is probably broken, there is no
>> phy-handle property or MDIO bus node, so it must be relying on
>> auto-scanning of the bus somehow that this patch broke.
>>
>> And likewise for most 64-bit platforms except a1 and nanopi4.
> 
> I primarily noticed that on the px30-evb.dts and the internal board I'm
> working on right now. Both don't have that mdio bus node right now.
> 
> 
>>> When probing the driver and trying to establish a connection for a nfsroot
>>> it always runs into a null pointer in mdiobus_get_phy():
>>>
>>> [   26.878839] rk_gmac-dwmac ff360000.ethernet: IRQ eth_wake_irq not found
>>> [   26.886322] rk_gmac-dwmac ff360000.ethernet: IRQ eth_lpi not found
>>> [   26.894505] rk_gmac-dwmac ff360000.ethernet: PTP uses main clock
>>> [   26.908209] rk_gmac-dwmac ff360000.ethernet: clock input or output? (output).
>>> [   26.916269] rk_gmac-dwmac ff360000.ethernet: Can not read property: tx_delay.
>>> [   26.924297] rk_gmac-dwmac ff360000.ethernet: set tx_delay to 0x30
>>> [   26.931150] rk_gmac-dwmac ff360000.ethernet: Can not read property: rx_delay.
>>> [   26.939166] rk_gmac-dwmac ff360000.ethernet: set rx_delay to 0x10
>>> [   26.946021] rk_gmac-dwmac ff360000.ethernet: integrated PHY? (no).
>>> [   26.953032] rk_gmac-dwmac ff360000.ethernet: cannot get clock clk_mac_refout
>>> [   26.966161] rk_gmac-dwmac ff360000.ethernet: init for RMII
>>> [   26.972633] rk_gmac-dwmac ff360000.ethernet: User ID: 0x10, Synopsys ID: 0x35
>>> [   26.980830] rk_gmac-dwmac ff360000.ethernet:         DWMAC1000
>>> [   26.986735] rk_gmac-dwmac ff360000.ethernet: DMA HW capability register supported
>>> [   26.995145] rk_gmac-dwmac ff360000.ethernet: RX Checksum Offload Engine supported
>>> [   27.003540] rk_gmac-dwmac ff360000.ethernet: COE Type 2
>>> [   27.009408] rk_gmac-dwmac ff360000.ethernet: TX Checksum insertion supported
>>> [   27.017320] rk_gmac-dwmac ff360000.ethernet: Wake-Up On Lan supported
>>> [   27.024577] rk_gmac-dwmac ff360000.ethernet: Normal descriptors
>>> [   27.031211] rk_gmac-dwmac ff360000.ethernet: Ring mode enabled
>>> [   27.037743] rk_gmac-dwmac ff360000.ethernet: Enable RX Mitigation via HW Watchdog Timer
>>> [   27.209823] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000398
>>>  2IP-Config: eth0 hardware address  66:e4:9b:b1:30:c3 mtu 1500 DHCP
>>> 7.219681] Mem abort info:
>>> [   27.229322]   ESR = 0x96000006
>>> [   27.229328]   EC = 0x25: DABT (current EL), IL = 32 bits
>>> [   27.229330]   SET = 0, FnV = 0
>>> [   27.229332]   EA = 0, S1PTW = 0
>>> [   27.229334] Data abort info:
>>> [   27.229336]   ISV = 0, ISS = 0x00000006
>>> [   27.229338]   CM = 0, WnR = 0
>>> [   27.229342] user pgtable: 4k pages, 48-bit VAs, pgdp=000000003e7d4000
>>> [   27.229345] [0000000000000398] pgd=0000000036739003, pud=0000000035894003, pmd=0000000000000000
>>> [   27.273398] Internal error: Oops: 96000006 [#1] SMP
>>> [   27.273403] Modules linked in: smsc95xx smsc75xx ax88179_178a asix usbnet panel_leadtek_ltk500hd1829 dwmac_rk stmmac_platform stmmac rockchipdrm phy_rockchip_inno_dsidphy analogix_dp dw_hdmi cec r
>>> c_core dw_mipi_dsi drm_kms_helper rtc_rk808 drm drm_panel_orientation_quirks
>>> [   27.305785] CPU: 3 PID: 1388 Comm: ipconfig Not tainted 5.5.0-rc4-00934-gd57e566e6874 #1463
>>> [   27.305790] Hardware name: Theobroma Systems Cobra with Leadtek Display (DT)
>>> [   27.323006] pstate: 40000005 (nZcv daif -PAN -UAO)
>>> [   27.323020] pc : mdiobus_get_phy+0x4/0x20
>>> [   27.332867] lr : stmmac_open+0x780/0xa78 [stmmac]
>>> [   27.332872] sp : ffff80001113b9a0
>>> [   27.341823] x29: ffff80001113b9a0 x28: 0000000000401003
>>> [   27.347761] x27: ffff00003d5cf200 x26: 0000000000000000
>>> [   27.353699] x25: 0000000000000001 x24: 0000000000000000
>>> [   27.359636] x23: 0000000000001002 x22: ffff800008b790a0
>>> [   27.365575] x21: ffff000035f84000 x20: 00000000ffffffff
>>> [   27.371513] x19: ffff000035f84800 x18: 0000000000000000
>>> [   27.377451] x17: 0000000000000000 x16: 0000000000000000
>>> [   27.383389] x15: 0000000000000000 x14: ffffffffffffffff
>>> [   27.389328] x13: 0000000000000020 x12: 0101010101010101
>>> [   27.395266] x11: 0000000000000003 x10: 0101010101010101
>>> [   27.401203] x9 : fffffffffffffffd x8 : 7f7f7f7f7f7f7f7f
>>> [   27.407143] x7 : fefefeff646c606d x6 : 1e091448e4e5f6e9
>>> [   27.413074] x5 : 697665644814091e x4 : 8080808000000000
>>> [   27.419013] x3 : 8343c96b232bb348 x2 : ffff00003d63f880
>>> [   27.424953] x1 : fffffffffffffff8 x0 : 0000000000000000
>>> [   27.430882] Call trace:
>>> [   27.433620]  mdiobus_get_phy+0x4/0x20
>>> [   27.437715]  __dev_open+0xe4/0x160
>>> [   27.441515]  __dev_change_flags+0x160/0x1b8
>>> [   27.446191]  dev_change_flags+0x20/0x60
>>> [   27.450478]  devinet_ioctl+0x66c/0x738
>>> [   27.454666]  inet_ioctl+0x2f4/0x360
>>> [   27.458565]  sock_do_ioctl+0x44/0x2b0
>>> [   27.462657]  sock_ioctl+0x1c8/0x508
>>> [   27.466556]  do_vfs_ioctl+0x604/0xbd0
>>> [   27.470646]  ksys_ioctl+0x78/0xa8
>>> [   27.474351]  __arm64_sys_ioctl+0x1c/0x28
>>> [   27.478737]  el0_svc_common.constprop.0+0x68/0x160
>>> [   27.484083]  el0_svc_handler+0x20/0x80
>>> [   27.488273]  el0_sync_handler+0x10c/0x180
>>> [   27.492753]  el0_sync+0x140/0x180
>>> [   27.496462] Code: 97ffffb0 a8c17bfd d65f03c0 8b21cc01 (f941d020)
>>> [   27.503275] ---[ end trace 6f6ca54e66af6d48 ]---
>>>
>>> With the expected output being normally at this point:
>>> [   18.575321] rk_gmac-dwmac ff360000.ethernet eth0: PHY [stmmac-0:00] driver [RTL8201F Fast Ethernet]
>>> [   18.602975] rk_gmac-dwmac ff360000.ethernet eth0: No Safety Features support found
>>> [   18.611505] rk_gmac-dwmac ff360000.ethernet eth0: PTP not supported by HW
>>> [   18.619117] rk_gmac-dwmac ff360000.ethernet eth0: configuring for phy/rmii link mode
>>> [   22.719478] rk_gmac-dwmac ff360000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
>>>
>>> or
>>>
>>> [   27.326984] rk_gmac-dwmac ff360000.ethernet eth0: PHY [stmmac-0:00] driver [Generic PHY]
>>> [   27.353543] rk_gmac-dwmac ff360000.ethernet eth0: No Safety Features support found
>>> [   27.362055] rk_gmac-dwmac ff360000.ethernet eth0: PTP not supported by HW
>>> [   27.369663] rk_gmac-dwmac ff360000.ethernet eth0: configuring for phy/rmii link mode
>>> [   29.406784] rk_gmac-dwmac ff360000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
>>>
>>>
>>> This is torvalds git head and it was still working at -rc1 and all kernels
>>> before that. When I just revert this commit, things also start working
>>> again, so I guess something must be wrong here?
>>
>> Yes, this was also identified to be problematic by the kernelci boot
>> farms on another platform, see [1].
>>
>> [1]:
>> https://lore.kernel.org/linux-arm-kernel/5e0314da.1c69fb81.a7d63.29c1@mx.google.com/
>>
>> Do you mind trying this patch and letting me know if it works for you.
>> Sriram, please also try it on your platforms and let me know if solves
>> the problem you were after. Thanks
> 
> Works on both boards I had that were affected, so
> Tested-by: Heiko Stuebner <heiko@sntech.de>

Thanks Heiko, I am keen on submitting the revert of the affected commit,
submit the second part where we actually ensure that the MDIO bus
controller node is available as net-next material, so hopefully the guys
at Samsung can test and response whether it fixes the problem they were
initially after.
--
Florian

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