Re: [PATCH] hw/usb/vt82c686-uhci-pci: Use ISA instead of PCI interrupts

[BALATON Zoltan]

On Sun, 3 Oct 2021, BALATON Zoltan wrote:
> This device is part of a sperio/ISA bridge chip and IRQs from it are
> routed to an ISA interrupt set by the Interrupt Line PCI config
> register. Change uhci_update_irq() to allow this and use it from
> vt82c686-uhci-pci.
>
> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
> ---
> Maybe bit of a hack but fixes USB interrupts on pegasos2 until
> somebody has a better idea. I'm not sure about fuloong2e but the
> VT82C686B docs say it also does the same routing IRQs to ISA PIC like
> VT8231 used on pegasos2.

I've found this breaks compilation for machines that have UHCI but no ISA 
so I'll have to cahnge it a bit to put a set_irq method in UHCIState 
instead that subclasses can set then implement the ISA irq mapping in 
vt82c686-uhci-pci.c which depends on VT82C686B which depends on ISA but 
the idea is the same unless somebody comes up with a better one. I'll send 
a v2 later.

Regards,
BALATON Zoltan

> hw/usb/hcd-uhci.c          | 12 +++++++++---
> hw/usb/hcd-uhci.h          |  1 +
> hw/usb/vt82c686-uhci-pci.c |  1 +
> 3 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
> index 0cb02a6432..8f28241f70 100644
> --- a/hw/usb/hcd-uhci.c
> +++ b/hw/usb/hcd-uhci.c
> @@ -31,6 +31,7 @@
> #include "hw/usb/uhci-regs.h"
> #include "migration/vmstate.h"
> #include "hw/pci/pci.h"
> +#include "hw/irq.h"
> #include "hw/qdev-properties.h"
> #include "qapi/error.h"
> #include "qemu/timer.h"
> @@ -290,7 +291,7 @@ static UHCIAsync *uhci_async_find_td(UHCIState *s, uint32_t 
> td_addr)
>
> static void uhci_update_irq(UHCIState *s)
> {
> -    int level;
> +    int level = 0;
>     if (((s->status2 & 1) && (s->intr & (1 << 2))) ||
>         ((s->status2 & 2) && (s->intr & (1 << 3))) ||
>         ((s->status & UHCI_STS_USBERR) && (s->intr & (1 << 0))) ||
> @@ -298,10 +299,15 @@ static void uhci_update_irq(UHCIState *s)
>         (s->status & UHCI_STS_HSERR) ||
>         (s->status & UHCI_STS_HCPERR)) {
>         level = 1;
> +    }
> +    if (s->isa_irqs) {
> +        uint8_t irq = pci_get_byte(s->dev.config + PCI_INTERRUPT_LINE);
> +        if (irq < ISA_NUM_IRQS) {
> +            qemu_set_irq(isa_get_irq(NULL, irq), level);
> +        }
>     } else {
> -        level = 0;
> +        pci_set_irq(&s->dev, level);
>     }
> -    pci_set_irq(&s->dev, level);
> }
>
> static void uhci_reset(DeviceState *dev)
> diff --git a/hw/usb/hcd-uhci.h b/hw/usb/hcd-uhci.h
> index e61d8fcb19..c91805a65e 100644
> --- a/hw/usb/hcd-uhci.h
> +++ b/hw/usb/hcd-uhci.h
> @@ -59,6 +59,7 @@ typedef struct UHCIState {
>     uint32_t frame_bytes;
>     uint32_t frame_bandwidth;
>     bool completions_only;
> +    bool isa_irqs;
>     UHCIPort ports[NB_PORTS];
>
>     /* Interrupts that should be raised at the end of the current frame.  */
> diff --git a/hw/usb/vt82c686-uhci-pci.c b/hw/usb/vt82c686-uhci-pci.c
> index b109c21603..5c79e293ef 100644
> --- a/hw/usb/vt82c686-uhci-pci.c
> +++ b/hw/usb/vt82c686-uhci-pci.c
> @@ -13,6 +13,7 @@ static void usb_uhci_vt82c686b_realize(PCIDevice *dev, Error 
> **errp)
>     /* USB legacy support  */
>     pci_set_long(pci_conf + 0xc0, 0x00002000);
>
> +    s->isa_irqs = true;
>     usb_uhci_common_realize(dev, errp);
> }