[Qemu-devel] [PATCH v3 0/2] 40p: fix PCI interrupt routing

[Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>]

According to the PReP specification section 6.1.6 "System Interrupt
Assignments", all PCI interrupts are routed via IRQ 15.

In the case of the 40p machine this isn't quite true in that it has a routing
quirk: the LSI SCSI device is always routed to IRQ 13. At least Linux and
NetBSD compare the model name presented by the firmware to "IBM PPS Model
6015", and if it matches will active this quirk.

In order for guest OSs to make use of the fixed IRQ routing, the model name
in the residual data must be changed in OpenBIOS using the diff below:

diff --git a/arch/ppc/qemu/context.c b/arch/ppc/qemu/context.c
index 06e0122..5815895 100644
--- a/arch/ppc/qemu/context.c
+++ b/arch/ppc/qemu/context.c
@@ -111,7 +111,7 @@ static void *
 residual_build(uint32_t memsize, uint32_t load_base, uint32_t load_size)
 {
     residual_t *res;
-    const unsigned char model[] = "Qemu\0PPC\0";
+    const unsigned char model[] = "IBM PPS Model 6015\0";
     int i;
 
     res = malloc(sizeof(residual_t));

With the above OpenBIOS patch applied as well as this patchset, it is now
possible to boot the sandalfoot zImage all the way through to a working
userspace when using OpenBIOS.

(Note: this patchset requires the changes in my previous patchset "scsi:
replace lsi53c895a_create() and lsi53c810_create() functions)

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Based-on: <20180907125653.5010-1-mark.cave-ayland@ilande.co.uk>

v3:
- Add external IRQ to LSI SCSI device instead of hacking the PCI interrupt
  routing as suggested by David
- Rebase onto the patches from v2 already applied to ppc-for-3.1

v2:
- Add OR gate as recommended by Zoltan and implement routing quirk by hacking
  the raven PCI interrupt routing


Mark Cave-Ayland (2):
  lsi53c895a: add optional external IRQ via qdev
  40p: add fixed IRQ routing for LSI SCSI device

 hw/ppc/prep.c        | 11 ++++++-----
 hw/scsi/lsi53c895a.c | 16 ++++++++++++++--
 2 files changed, 20 insertions(+), 7 deletions(-)

-- 
2.11.0