Re: [PATCH v3 4/8] hw/isa/vt82c686: Implement PCI IRQ routing

[Bernhard Beschow]

Am 25. Februar 2023 18:11:49 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>From: Bernhard Beschow <shentey@gmail.com>
>
>The real VIA south bridges implement a PCI IRQ router which is configured
>by the BIOS or the OS. In order to respect these configurations, QEMU
>needs to implement it as well.
>
>Note: The implementation was taken from piix4_set_irq() in hw/isa/piix4.
>
>Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>[balaton: declare gpio inputs instead of changing pci bus irqs so it can
> be connected in board code; remove some empty lines]
>Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
>Tested-by: Rene Engel <ReneEngel80@emailn.de>
>---
> hw/isa/vt82c686.c | 39 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
>diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
>index 3f9bd0c04d..4025f9bcdc 100644
>--- a/hw/isa/vt82c686.c
>+++ b/hw/isa/vt82c686.c
>@@ -604,6 +604,44 @@ static void via_isa_request_i8259_irq(void *opaque, int 
>irq, int level)
>     qemu_set_irq(s->cpu_intr, level);
> }
> 
>+static int via_isa_get_pci_irq(const ViaISAState *s, int irq_num)
>+{
>+    switch (irq_num) {
>+    case 0:
>+        return s->dev.config[0x55] >> 4;
>+    case 1:
>+        return s->dev.config[0x56] & 0xf;
>+    case 2:
>+        return s->dev.config[0x56] >> 4;
>+    case 3:
>+        return s->dev.config[0x57] >> 4;
>+    }
>+    return 0;
>+}
>+
>+static void via_isa_set_pci_irq(void *opaque, int irq_num, int level)
>+{
>+    ViaISAState *s = opaque;
>+    PCIBus *bus = pci_get_bus(&s->dev);
>+    int pic_irq;
>+
>+    /* now we change the pic irq level according to the via irq mappings */
>+    /* XXX: optimize */
>+    pic_irq = via_isa_get_pci_irq(s, irq_num);
>+    if (pic_irq < ISA_NUM_IRQS) {
>+        int i, pic_level;
>+
>+        /* The pic level is the logical OR of all the PCI irqs mapped to it. 
>*/
>+        pic_level = 0;
>+        for (i = 0; i < PCI_NUM_PINS; i++) {
>+            if (pic_irq == via_isa_get_pci_irq(s, i)) {
>+                pic_level |= pci_bus_get_irq_level(bus, i);
>+            }
>+        }
>+        qemu_set_irq(s->isa_irqs[pic_irq], pic_level);
>+    }
>+}
>+
> static void via_isa_realize(PCIDevice *d, Error **errp)
> {
>     ViaISAState *s = VIA_ISA(d);
>@@ -614,6 +652,7 @@ static void via_isa_realize(PCIDevice *d, Error **errp)
>     int i;
> 
>     qdev_init_gpio_out(dev, &s->cpu_intr, 1);
>+    qdev_init_gpio_in_named(dev, via_isa_set_pci_irq, "pirq", PCI_NUM_PINS);

This line is a Pegasos2 specific addition for fixing its IRQ handling. Since 
this code must also work with the Fuloong2e board we should aim for a minimal 
changeset here which renders this line out of scope.

Let's keep the two series separate since now I need to watch two series for 
comments. Please use Based-on: tag next time instead.

Thanks,
Bernhard

>     isa_irq = qemu_allocate_irqs(via_isa_request_i8259_irq, s, 1);
>     isa_bus = isa_bus_new(dev, pci_address_space(d), pci_address_space_io(d),
>                           errp);