Re: [PATCH v3] hw/usb/vt82c686-uhci-pci: Use ISA instead of PCI interrupts

[Philippe Mathieu-Daudé]

On 10/13/21 14:13, BALATON Zoltan wrote:
> This device is part of a superio/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 implement it in
> vt82c686-uhci-pci.
> 
> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
> v3: Do it more differently using qemu_irq instead as suggested by Gerd
> v2: Do it differently to confine isa reference to vt82c686-uhci-pci as
> hcd-uhci is also used on machines that don't have isa. Left Jiaxun's
> R-b there as he checked it's the same for VT82C686B and gave R-b for
> the 82c686b case which still holds but speak up if you tink otherwise.
> 
>  hw/usb/hcd-uhci.c          | 11 +++++------
>  hw/usb/hcd-uhci.h          |  2 +-
>  hw/usb/vt82c686-uhci-pci.c | 12 ++++++++++++
>  3 files changed, 18 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
> index 0cb02a6432..7201cd0ae7 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 +299,8 @@ static void uhci_update_irq(UHCIState *s)
>          (s->status & UHCI_STS_HSERR) ||
>          (s->status & UHCI_STS_HCPERR)) {
>          level = 1;
> -    } else {
> -        level = 0;
>      }
> -    pci_set_irq(&s->dev, level);
> +    qemu_set_irq(s->irq, level);
>  }

^ OK.

>  static void uhci_reset(DeviceState *dev)
> @@ -1170,9 +1169,9 @@ void usb_uhci_common_realize(PCIDevice *dev, Error 
> **errp)
>  
>      pci_conf[PCI_CLASS_PROG] = 0x00;
>      /* TODO: reset value should be 0. */
> -    pci_conf[USB_SBRN] = USB_RELEASE_1; // release number
> -
> +    pci_conf[USB_SBRN] = USB_RELEASE_1; /* release number */
>      pci_config_set_interrupt_pin(pci_conf, u->info.irq_pin + 1);
> +    s->irq = pci_allocate_irq(dev);
>  
>      if (s->masterbus) {
>          USBPort *ports[NB_PORTS];

usb_uhci_common_realize() should be refactored making it PCI-agnostic.

> diff --git a/hw/usb/hcd-uhci.h b/hw/usb/hcd-uhci.h
> index e61d8fcb19..1f8ee04186 100644
> --- a/hw/usb/hcd-uhci.h
> +++ b/hw/usb/hcd-uhci.h
> @@ -60,7 +60,7 @@ typedef struct UHCIState {
>      uint32_t frame_bandwidth;
>      bool completions_only;
>      UHCIPort ports[NB_PORTS];
> -
> +    qemu_irq irq;
>      /* Interrupts that should be raised at the end of the current frame.  */
>      uint32_t pending_int_mask;

OK.

> diff --git a/hw/usb/vt82c686-uhci-pci.c b/hw/usb/vt82c686-uhci-pci.c
> index b109c21603..e70e739409 100644
> --- a/hw/usb/vt82c686-uhci-pci.c
> +++ b/hw/usb/vt82c686-uhci-pci.c
> @@ -1,6 +1,16 @@
>  #include "qemu/osdep.h"
> +#include "hw/irq.h"
>  #include "hcd-uhci.h"
>  
> +static void uhci_isa_set_irq(void *opaque, int irq_num, int level)
> +{
> +    UHCIState *s = opaque;
> +    uint8_t irq = pci_get_byte(s->dev.config + PCI_INTERRUPT_LINE);
> +    if (irq > 0 && irq < 15) {
> +        qemu_set_irq(isa_get_irq(NULL, irq), level);
> +    }
> +}

OK.

>  static void usb_uhci_vt82c686b_realize(PCIDevice *dev, Error **errp)
>  {
>      UHCIState *s = UHCI(dev);
> @@ -14,6 +24,8 @@ static void usb_uhci_vt82c686b_realize(PCIDevice *dev, 
> Error **errp)
>      pci_set_long(pci_conf + 0xc0, 0x00002000);
>  
>      usb_uhci_common_realize(dev, errp);
> +    object_unref(s->irq);
> +    s->irq = qemu_allocate_irq(uhci_isa_set_irq, s, 0);

This can be avoided by refactoring usb_uhci_common_realize(),
uhci_pci_type_info and uhci_data_class_init().

Current TYPE_UHCI becomes TYPE_PCI_UHCI.

Not sure why UHCI has been implemented that way, we already
have USB_OHCI_PCI / USB_EHCI_PCI / USB_XHCI_PCI.

Maybe look at how TYPE_SYSBUS_OHCI is implemented VS TYPE_PCI_OHCI
to be able to implement the similar TYPE_SYSBUS_UHCI?