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Re: [Qemu-arm] [PATCH 3/3] arm: allwinner: Enable USB EHCI
From: |
Guenter Roeck |
Subject: |
Re: [Qemu-arm] [PATCH 3/3] arm: allwinner: Enable USB EHCI |
Date: |
Wed, 7 Nov 2018 10:38:19 -0800 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Mon, Nov 05, 2018 at 09:16:56AM +0100, Gerd Hoffmann wrote:
> > > > @@ -116,6 +116,8 @@ static void aw_a10_realize(DeviceState *dev, Error
> > > > **errp)
> > > > if (machine_usb(current_machine)) {
> > > > sysbus_create_simple("sysbus-ohci", 0x01c14400, s->irq[64]);
> > > > sysbus_create_simple("sysbus-ohci", 0x01c1c400, s->irq[65]);
> > > > + sysbus_create_simple(TYPE_AW_A10_EHCI, 0x01c14000, s->irq[39]);
> > > > + sysbus_create_simple(TYPE_AW_A10_EHCI, 0x01c1c000, s->irq[40]);
> > >
> > > Hmm, is this a companion controller setup? If so, then this is a bit
> > > more complicated (see ehci_create_ich9_with_companions()).
> >
> > I don't have enough USB knowledge. Can we have companion setup without PCI?
> >
> > Per the datashit [1] p. 215 "21. USB Host Controller", each controller share
> > the same PHY. There is no mention of companion setup:
> >
> > The USB host controller includes the following features:
> > ..
> > - Complies with EHCI Specification, Version 1.0,
> > - and the OHCI Specification, Version 1.0a.
> > ..
> > - Support only 1 USB Root Port shared between EHCI and OHCI.
>
> Looks like a companion setup. Short introduction:
>
> The port is shared, and ehci controls whenever the port is assigned to
> ehci or the companion (ohci in this case). Typically the ehci driver
> sets the bit depending on usb device speed, i.e. usb2 devices are
> handled by ehci and usb1 devices are handled by ohci.
>
> By default ohci owns the devices, so in case the OS has no ehci driver
> ohci can be used to handle usb2 devices in usb1 compat mode. Pretty
> much moot these days.
>
> On the qemu side you basically have to initialize ehci first (so the usb
> bus exists), then set the masterbus property to the ehci usb-bus for the
> ohci controller.
>
I tried that; in theory it looks like it works, or at least both devices
instantiate. I took the implementation from hw/ppc/sam460ex.c as guideline.
In practice, however, it doesn't work (nor does my current code). EHCI
fails to instantiate with error -110, and OHCI fails to instantiate with
error -75.
Weird, I know I tested this when I implemented it. Nevertheless,
it doesn't work. Given that, I think the series should be dropped
for now, at least until I find the time to track down the problem.
Guenter