[PATCH 04/13] arm: mach-k3: j721s2_init: Probe AM65 CPSW NUSS for R5/A72 SPL

[Roger Quadros]

+Vignesh & Siddharth

On 22/01/2025 10:53, Chintan Vankar wrote:
> 
> 
> On 07/01/25 20:03, Roger Quadros wrote:
>>
>>
>> On 07/01/2025 11:38, Chintan Vankar wrote:
>>> To support Ethernet boot on AM68-SK, probe AM65 CPSW NUSS driver in
>>> board_init_f().
>>>
>>> Signed-off-by: Chintan Vankar <c-vankar at ti.com>
>>> ---
>>>   arch/arm/mach-k3/j721s2/j721s2_init.c | 10 ++++++++++
>>>   1 file changed, 10 insertions(+)
>>>
>>> diff --git a/arch/arm/mach-k3/j721s2/j721s2_init.c b/arch/arm/mach-k3/j721s2/j721s2_init.c
>>> index 6ce3eb87efb..7208bee5785 100644
>>> --- a/arch/arm/mach-k3/j721s2/j721s2_init.c
>>> +++ b/arch/arm/mach-k3/j721s2/j721s2_init.c
>>> @@ -329,6 +329,16 @@ void board_init_f(ulong dummy)
>>>         setup_qos();
>>>   +    if (IS_ENABLED(CONFIG_SPL_ETH) && IS_ENABLED(CONFIG_TI_AM65_CPSW_NUSS) &&
>>> +        spl_boot_device() == BOOT_DEVICE_ETHERNET) {
>>> +        struct udevice *cpswdev;
>>> +
>>> +        ret = uclass_get_device_by_driver(UCLASS_MISC, DM_DRIVER_GET(am65_cpsw_nuss),
>>> +                          &cpswdev);
>>> +        if (ret)
>>> +            printf("Failed to probe am65_cpsw_nuss driver..\n");
>>> +    }
>>> +
>>
>> This looks like a hack. Please find out why the Ethernet driver is not being
>> probed when SPL tries to load image over net.
>>
> 
> Hello Roger,
> 
> The driver is defined as UCLASS_MISC which should be probed explicitly,

The driver was originally built without UCLASS_MISC, but

commit 38922b1f4acc ("net: ti: am65-cpsw: Add support for multi port independent MAC mode")

Added UCLASS_MISC and states there that 
" Since top level driver is now UCLASS_MISC, board files would need to
  instantiate this driver explicitly."

Not an elegant solution. So we need to fix something in the am65-cpuss driver.

Looking at drivers/net/mvpp2.c we can see a possible solution.
1) don't define .probe for the parent driver (UCLASS_MISC). Instead define .bind
that will scan the device tree for ports and bind the port device and driver.
e.g. see mvpp2_base_bind()
2) in port driver .probe (UCLASS_ETH), if parent has not been probed
then call the parent probe (am65_cpsw_probe_nuss) . Also set a flag so parent probe
only gets called once.
3) update all board files no not explicitly probe the am65-cpsw UCLASS_MISC driver.

Siddharth / Vignesh do you see any issues with this solution?

> I have discussed the same with Nishanth in following thread:
> https://lore.kernel.org/all/ee1d16fd-b99b-4b07-97bb-a896e179157a@ti.com/
> 
>> We have the following defined at the am65-cpsw-nuss driver.
>>
>> U_BOOT_DRIVER(am65_cpsw_nuss) = {
>>          .name   = "am65_cpsw_nuss",
>>          .id     = UCLASS_MISC,
>>          .of_match = am65_cpsw_nuss_ids,
>>          .probe  = am65_cpsw_probe_nuss,
>>          .priv_auto = sizeof(struct am65_cpsw_common),
>> };
>>
>> U_BOOT_DRIVER(am65_cpsw_nuss_port) = {
>>          .name   = "am65_cpsw_nuss_port",
>>          .id     = UCLASS_ETH,
>>          .probe  = am65_cpsw_port_probe,
>>          .ops    = &am65_cpsw_ops,
>>          .priv_auto      = sizeof(struct am65_cpsw_priv),
>>          .plat_auto      = sizeof(struct eth_pdata),
>>          .flags = DM_FLAG_ALLOC_PRIV_DMA | DM_FLAG_OS_PREPARE,
>> };
>>
>> It looks like am65_cpsw_probe_nuss() is not being invoked for you.
>>
>> Can you please check if am65_cpsw_port_probe() was invoked?
>> If yes but am65_cpsw_probe_nuss() was not then we need to fix the
>> DM hierarchy for AM65_CPSW?
>>
> None of the probe function is getting invoked here, since we need

That is strange. am65_cpsw_probe_nuss() should be called at least for
port 0 since it is defined as UCLASS_ETH.

> Ethernet functionality here we need to probe function in board_init_f().
> We have discussed the same at here:
> https://lore.kernel.org/r/d68c8045-116a-49c0-9e74-d6a366e6f008@kernel.org/#t
> 
> 
>>>       if (IS_ENABLED(CONFIG_CPU_V7R) && IS_ENABLED(CONFIG_K3_AVS0)) {
>>>           ret = uclass_get_device_by_driver(UCLASS_MISC, DM_DRIVER_GET(k3_avs),
>>>                             &dev);
>>

-- 
cheers,
-roger