powerpc/pmac: Fix internal modem IRQ on Wallstreet PowerBook

The (relatively) new pmac_zilog driver doesn't use the pre-munged
IRQ numbers from the macio_dev unlike other macio things, it
directly maps it off the OF device-tree.

It does that because it can be initialized much earlier than the
registration of the macio devices, in order to get a serial
console early.

Unfortunately, that means that it "misses" some fixups done
by the macio layer to work around missing interrupt descriptions
in the device-tree of the Wallstreet machines.

This patch brings the necessary workaround into the pmac_zilog
driver itself to bring it back to working condition.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/serial/pmac_zilog.c b/drivers/serial/pmac_zilog.c
index ad3488504010..9c1243fbd512 100644
--- a/drivers/serial/pmac_zilog.c
+++ b/drivers/serial/pmac_zilog.c
@@ -1538,6 +1538,21 @@ no_dma:
         uap->port.type = PORT_PMAC_ZILOG;
         uap->port.flags = 0;
 
+        /*
+         * Fixup for the port on Gatwick for which the device-tree has
+         * missing interrupts. Normally, the macio_dev would contain
+         * fixed up interrupt info, but we use the device-tree directly
+         * here due to early probing so we need the fixup too.
+         */
+        if (uap->port.irq == NO_IRQ &&
+            np->parent && np->parent->parent &&
+            of_device_is_compatible(np->parent->parent, "gatwick")) {
+                /* IRQs on gatwick are offset by 64 */
+                uap->port.irq = irq_create_mapping(NULL, 64 + 15);
+                uap->tx_dma_irq = irq_create_mapping(NULL, 64 + 4);
+                uap->rx_dma_irq = irq_create_mapping(NULL, 64 + 5);
+        }
+
         /* Setup some valid baud rate information in the register
          * shadows so we don't write crap there before baud rate is
          * first initialized.