Re: [PATCH for-9.0] ppc440_pcix: Do not expose a bridge device on PCI bus

[BALATON Zoltan]

On Wed, 10 Apr 2024, Nicholas Piggin wrote:
On Wed Apr 10, 2024 at 9:55 AM AEST, BALATON Zoltan wrote:
Real 460EX SoC apparently does not expose a bridge device and having
it appear on PCI bus confuses an AmigaOS file system driver that uses
this to detect which machine it is running on. Since values written
here by firmware are never read, just ignore these writes and drop the
bridge device.
Signed-off-by: BALATON Zoltan <bala...@eik.bme.hu>
---
This is only used by sam460ex and this fixes an issue with AmigaOS on
this machine so I'd like this to be merged for 9.0 please.

Is it a regression? Does it have a fixes: or resolves: tag?

Unless we broke it in this cycle, I would be inclined to wait,
and we can ask to put it in stable.

It's not something that broke in this cycle but since this does not affect 
anything else than sam460ex I think it's OK to change this for 9.0. The 
changes to 440 tlb in this cycle made sam460ex more useful to run AmigaOS 
and this fixes the file system driver on it so it would make 9.0 really 
usable. Otherwise people would have to wait longer until August or install 
a stable update. Since this has low chance to break anything (tested with 
AmogaOS and Linux and MorphOS does not boot due to do_io changes anyway) I 
don't think we have to wait with this.

Regards,
BALATON Zoltan

Thanks,
Nick


 hw/pci-host/ppc440_pcix.c | 14 +-------------
 1 file changed, 1 insertion(+), 13 deletions(-)

diff --git a/hw/pci-host/ppc440_pcix.c b/hw/pci-host/ppc440_pcix.c
index 1926ae2a27..ba38172989 100644
--- a/hw/pci-host/ppc440_pcix.c
+++ b/hw/pci-host/ppc440_pcix.c
@@ -52,7 +52,6 @@ OBJECT_DECLARE_SIMPLE_TYPE(PPC440PCIXState, PPC440_PCIX_HOST)
 struct PPC440PCIXState {
     PCIHostState parent_obj;

-    PCIDevice *dev;
     struct PLBOutMap pom[PPC440_PCIX_NR_POMS];
     struct PLBInMap pim[PPC440_PCIX_NR_PIMS];
     uint32_t sts;
@@ -170,10 +169,6 @@ static void ppc440_pcix_reg_write4(void *opaque, hwaddr 
addr,

     trace_ppc440_pcix_reg_write(addr, val, size);
     switch (addr) {
-    case PCI_VENDOR_ID ... PCI_MAX_LAT:
-        stl_le_p(s->dev->config + addr, val);
-        break;
-
     case PCIX0_POM0LAL:
         s->pom[0].la &= 0xffffffff00000000ULL;
         s->pom[0].la |= val;
@@ -301,10 +296,6 @@ static uint64_t ppc440_pcix_reg_read4(void *opaque, hwaddr 
addr,
     uint32_t val;

     switch (addr) {
-    case PCI_VENDOR_ID ... PCI_MAX_LAT:
-        val = ldl_le_p(s->dev->config + addr);
-        break;
-
     case PCIX0_POM0LAL:
         val = s->pom[0].la;
         break;
@@ -498,10 +489,7 @@ static void ppc440_pcix_realize(DeviceState *dev, Error 
**errp)
     memory_region_init(&s->iomem, OBJECT(dev), "pci-io", 64 * KiB);
     h->bus = pci_register_root_bus(dev, NULL, ppc440_pcix_set_irq,
                          ppc440_pcix_map_irq, &s->irq, &s->busmem, &s->iomem,
-                         PCI_DEVFN(0, 0), 1, TYPE_PCI_BUS);
-
-    s->dev = pci_create_simple(h->bus, PCI_DEVFN(0, 0),
-                               TYPE_PPC4xx_HOST_BRIDGE);
+                         PCI_DEVFN(1, 0), 1, TYPE_PCI_BUS);

     memory_region_init(&s->bm, OBJECT(s), "bm-ppc440-pcix", UINT64_MAX);
     memory_region_add_subregion(&s->bm, 0x0, &s->busmem);