
: pci-gen-irq-map-one ( prop-addr prop-len slot pin -- prop-addr prop-len )
        2dup + 4 mod                ( prop-addr prop-len slot pin parentpin )
        >r >r                       ( prop-addr prop-len slot R: swizzledpin pin )

        \ Child slot#
        B lshift encode-int+        ( prop-addr prop-len R: swizzledpin pin )
        \ Child 64bit BAR (not really used)
        0 encode-64+
        \ Chile pin#
        r> encode-int+              ( prop-addr prop-len R: swizzledpin )

        \ Parent phandle
        get-parent encode-int+

        \ Parent slot#
        get-node >space
        pci-addr2dev B lshift       ( prop-addr prop-len parent-slot R: swizzledpin )
        encode-int+
        \ Parent 64bit BAR (not really used)
        0 encode-64+
        \ Parent pin
        r> encode-int+              ( prop-addr prop-len R: )
;

: pci-gen-irq-entry ( prop-addr prop-len config-addr -- prop-addr prop-len )
        pci-addr2dev 4 mod          ( prop-addr prop-len slot )
        -rot                        ( slot prop-addr prop-len )
        5 1 DO
                2 pick i            ( slot prop-addr prop-len slot pin )
                pci-gen-irq-map-one
        LOOP
        rot drop
;

: pci-set-irq-line ( config-addr -- )
  drop
;


: pci-gen-irq-map-one ( prop-addr prop-len slot pin -- prop-addr prop-len )
        2dup + 1- 3 and 1+          ( prop-addr prop-len slot pin parentpin )
        >r >r                       ( prop-addr prop-len slot R: swizzledpin pin )

        \ Child slot#
        B lshift encode-int+        ( prop-addr prop-len R: swizzledpin pin )
        \ Child 64bit BAR (not really used)
        0 encode-64+
        \ Chile pin#
        r> encode-int+              ( prop-addr prop-len R: swizzledpin )

        \ Parent phandle
        get-parent encode-int+

        \ Parent slot#
        get-node >space
        pci-addr2dev B lshift       ( prop-addr prop-len parent-slot R: swizzledpin )
        encode-int+
        \ Parent 64bit BAR (not really used)
        0 encode-64+
        \ Parent pin
        r> encode-int+              ( prop-addr prop-len R: )
;

: pci-gen-irq-entry ( prop-addr prop-len config-addr -- prop-addr prop-len )
        pci-addr2dev 4 mod          ( prop-addr prop-len slot )
        -rot                        ( slot prop-addr prop-len )
        5 1 DO
                2 pick i            ( slot prop-addr prop-len slot pin )
                pci-gen-irq-map-one
        LOOP
        rot drop
;

: pci-set-irq-line ( config-addr -- )
  drop
;

Fix bad interrupt pin numbering in interrupt-map property of PCI bridges
Fix bad interrupt pin numbering in interrupt-map property of PCI bridges

The legacy PCI interrupts in the device tree are enumerated from 1
to 4. However, the code in pci-gen-irq-map-one generates numbers
between 0 and 3 instead. This renders devices unusable by Linux
in case they should use IRQ 4. For example, when starting QEMU with

 qemu-system-ppc64 ... \
    -device pci-bridge,bus=pci.0,id=bridge1,chassis_nr=1,addr=0x6 \
    -device virtio-balloon-pci,id=balloon0,bus=bridge1,addr=3

Linux can not use the balloon device since it is unable to determine
the right IRQ number in this case.
To fix this issue, we've simply got to make sure that the IRQ
numbers are in the range from 1 to 4 instead of 0 to 3.

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1366953
Signed-off-by: Thomas Huth <9e65be74847981e55b2564b6266c57d86d3bac05@redhat.com>
Signed-off-by: Alexey Kardashevskiy <ac1fc56530d7d037e1ea666f130daca22d72f964@ozlabs.ru>
