[U-Boot] [PATCH] arm64: allwinner: a64: Disable ehci1 and ohci1 for bananapi, nanopi

[Jagan Teki]

On Tue, Jul 3, 2018 at 3:10 AM, Tom Rini <trini at konsulko.com> wrote:
> On Mon, Jul 02, 2018 at 11:27:58PM +0200, Marek Vasut wrote:
>> On 07/02/2018 10:53 PM, Jagan Teki wrote:
>> > During usb shutdown or 'usb reset' all the necessary clocks
>> > on the specific controller will disable. Usually this shutdown
>> > happen during U-Boot proper handoff to Linux.
>>
>> No, 'usb reset' can be triggered by the user any time.
>
> Yes, and it's also triggered as part of the hand-off, which is the use
> case in question.
>
>> > There is an issue in Allwinner A64, is during OHCI1 shutdown
>> > the controller is unable to access the register space
>> > so the Linux boot hangs at this place.
>>
>> This doesn't make any sense, Linux should enable the necessary clock
>> before accessing any controller registers, unless there is a bug in Linux.
>
> Should but doesn't always?  So yes, there's possibly / hopefully a bug
> in the dts files.
>
>> > This particular condition occur when we enable both the
>> > controllers, so this patch will disable OHCI1 and EHCI1 for
>> > bananapi-m64 and nanopi-a64 boards. It will re-enable the same
>> > once the issue got fixed.
>> >
>> > Log:
>> > => usb reset
>> > resetting USB...
>> >
>> > PHY0: mask = 0x101, usb_clk_cfg = 0x30202
>> > sunxi_musb_exit: ahb_gate0  = 0x33004540, reset0_cfg = 0x33004540
>> > EHCI failed to shut down host controller.
>> > ehci_usb_remove: ahb_gate0  = 0x32004540, reset0_cfg = 0x32004540
>> > ohci_usb_remove: ahb_gate0  = 0x22004540, reset0_cfg = 0x22004540
>> > ohci_usb_remove: mask = 0x10000, usb_clk_cfg = 0x20202
>> >
>> > PHY1: mask = 0x202, usb_clk_cfg = 0x0
>> > ehci_usb_remove: ahb_gate0  = 0x20004540, reset0_cfg = 0x20004540
>>
>> Why is this usb reset so noisy ?
>
> ... I would assume additional debug messages.
>
>> > << hang here >>
>>
>> Please fix this properly, this patch is pure attempt to hide a bug.
>> NAK from me.
>
> Well, the point of this patch as Jagan says is to hide the bug for the
> release so that Linux can boot, which is an important case.
>
> Jagan, can you bisect down to when this started happening?  I assume
> it's a recent'ish thing.  Thanks!

commit b62cdbddedc3 ("sunxi: clock: Fix EHCI and OHCI clocks on A64")
is effecting this change, but functionally this commit is proper but
handling clock directly in drivers look not effective particularly in
the case of A64 where sharing of clocks and gates between OHCI and
EHCI.

Here are the possible changes to look at it.

1)  with this patch, disabling [oe]hci1 controllers on two boards (bpi
and nanopi):
      this change specific to two boards, rest of A64 boards are OK.

2)  turn-off gate and clocks for H3/H5/A64 from Andre [1]
      this would change all H3/H5/A64 shutdown behavior not to disable
gates and clocks during .remove

3)  turn-off clock only for A64
     this would fix, two board problems in 1) and also specific to A64.

4)  add counter mechanism to disable all clock at once, suggested by Marek
     either we can add counter mechanism to A64 or for all other SOC.
this need to test in all Allwinner boards if the counter is globally
managed in ohci-sunxi.c

Again, there is an ongoing work for syncing all DT changes from Linux,
by Andre. 1) change will update later in the release. rest of 2), 3)
and 4) will make changes in driver [eo]hci-sunxi.c and this drivers
indeed remove once we have dm clock which would also planned for
upcoming releases.

[1] https://patchwork.ozlabs.org/patch/938279/

Jagan.