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

[Tom Rini]

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!

-- 
Tom
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