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authorDavid S. Miller <davem@davemloft.net>2008-09-19 15:33:21 -0700
committerDavid S. Miller <davem@davemloft.net>2008-09-19 21:18:05 -0700
commit778b1c65bfa2bfe4018394480f97d387e8f00a91 (patch)
treed8c83ee8c31c89cf9cdbc34163c4d284c3801922 /arch/sparc/kernel/sun4m_irq.c
parente7913de9285a4e40733cdabbe62b6f1fa3bbdf01 (diff)
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sparc32: Add more extensive documentation of sun4m interrupts.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc/kernel/sun4m_irq.c')
-rw-r--r--arch/sparc/kernel/sun4m_irq.c53
1 files changed, 53 insertions, 0 deletions
diff --git a/arch/sparc/kernel/sun4m_irq.c b/arch/sparc/kernel/sun4m_irq.c
index c6096fc..ec66d4a 100644
--- a/arch/sparc/kernel/sun4m_irq.c
+++ b/arch/sparc/kernel/sun4m_irq.c
@@ -87,6 +87,59 @@ struct sun4m_irq_global __iomem *sun4m_irq_global;
#define SUN4M_INT_SBUS(x) (1 << (x+7))
#define SUN4M_INT_VME(x) (1 << (x))
+/* Interrupt level assignment on sun4m:
+ *
+ * level source
+ * ------------------------------------------------------------
+ * 1 softint-1
+ * 2 softint-2, VME/SBUS level 1
+ * 3 softint-3, VME/SBUS level 2
+ * 4 softint-4, onboard SCSI
+ * 5 softint-5, VME/SBUS level 3
+ * 6 softint-6, onboard ETHERNET
+ * 7 softint-7, VME/SBUS level 4
+ * 8 softint-8, onboard VIDEO
+ * 9 softint-9, VME/SBUS level 5, Module Interrupt
+ * 10 softint-10, system counter/timer
+ * 11 softint-11, VME/SBUS level 6, Floppy
+ * 12 softint-12, Keyboard/Mouse, Serial
+ * 13 softint-13, VME/SBUS level 7, ISDN Audio
+ * 14 softint-14, per-processor counter/timer
+ * 15 softint-15, Asynchronous Errors (broadcast)
+ *
+ * Each interrupt source is masked distinctly in the sun4m interrupt
+ * registers. The PIL level alone is therefore ambiguous, since multiple
+ * interrupt sources map to a single PIL.
+ *
+ * This ambiguity is resolved in the 'intr' property for device nodes
+ * in the OF device tree. Each 'intr' property entry is composed of
+ * two 32-bit words. The first word is the IRQ priority value, which
+ * is what we're intersted in. The second word is the IRQ vector, which
+ * is unused.
+ *
+ * The low 4 bits of the IRQ priority indicate the PIL, and the upper
+ * 4 bits indicate onboard vs. SBUS leveled vs. VME leveled. 0x20
+ * means onboard, 0x30 means SBUS leveled, and 0x40 means VME leveled.
+ *
+ * For example, an 'intr' IRQ priority value of 0x24 is onboard SCSI
+ * whereas a value of 0x33 is SBUS level 2. Here are some sample
+ * 'intr' property IRQ priority values from ss4, ss5, ss10, ss20, and
+ * Tadpole S3 GX systems.
+ *
+ * esp: 0x24 onboard ESP SCSI
+ * le: 0x26 onboard Lance ETHERNET
+ * p9100: 0x32 SBUS level 1 P9100 video
+ * bpp: 0x33 SBUS level 2 BPP parallel port device
+ * DBRI: 0x39 SBUS level 5 DBRI ISDN audio
+ * SUNW,leo: 0x39 SBUS level 5 LEO video
+ * pcmcia: 0x3b SBUS level 6 PCMCIA controller
+ * uctrl: 0x3b SBUS level 6 UCTRL device
+ * modem: 0x3d SBUS level 7 MODEM
+ * zs: 0x2c onboard keyboard/mouse/serial
+ * floppy: 0x2b onboard Floppy
+ * power: 0x22 onboard power device (XXX unknown mask bit XXX)
+ */
+
/* These tables only apply for interrupts greater than 15..
*
* any intr value below 0x10 is considered to be a soft-int
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