path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2009-12-22 14:18:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-22 14:18:13 -0800
commitdd508ae2dbff0cfc7401eb6e278339fc56bc5033 (patch)
treedaa9f88a4e2e65e86b351ffa2d52dcc07e753c1e /Documentation
parent7801edb0b8b66e83c13623b483bc2e846c007c9d (diff)
parent95cd34b42b43c0ed5a89a764e023189bfe7b1530 (diff)
Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (36 commits) powerpc/gc/wii: Remove get_irq_desc() powerpc/gc/wii: hlwd-pic: convert irq_desc.lock to raw_spinlock powerpc/gamecube/wii: Fix off-by-one error in ugecon/usbgecko_udbg powerpc/mpic: Fix problem that affinity is not updated powerpc/mm: Fix stupid bug in subpge protection handling powerpc/iseries: use DECLARE_COMPLETION_ONSTACK for non-constant completion powerpc: Fix MSI support on U4 bridge PCIe slot powerpc: Handle VSX alignment faults correctly in little-endian mode powerpc/mm: Fix typo of cpumask_clear_cpu() powerpc/mm: Fix hash_utils_64.c compile errors with DEBUG enabled. powerpc: Convert BUG() to use unreachable() powerpc/pseries: Make declarations of cpu_hotplug_driver_lock() ANSI compatible. powerpc/pseries: Don't panic when H_PROD fails during cpu-online. powerpc/mm: Fix a WARN_ON() with CONFIG_DEBUG_PAGEALLOC and CONFIG_DEBUG_VM powerpc/defconfigs: Set HZ=100 on pseries and ppc64 defconfigs powerpc/defconfigs: Disable token ring in powerpc defconfigs powerpc/defconfigs: Reduce 64bit vmlinux by making acenic and cramfs modules powerpc/pseries: Select XICS and PCI_MSI PSERIES powerpc/85xx: Wrong variable returned on error powerpc/iseries: Convert to proc_fops ...
Diffstat (limited to 'Documentation')
1 files changed, 42 insertions, 0 deletions
diff --git a/Documentation/powerpc/dts-bindings/fsl/mpic.txt b/Documentation/powerpc/dts-bindings/fsl/mpic.txt
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+* OpenPIC and its interrupt numbers on Freescale's e500/e600 cores
+The OpenPIC specification does not specify which interrupt source has to
+become which interrupt number. This is up to the software implementation
+of the interrupt controller. The only requirement is that every
+interrupt source has to have an unique interrupt number / vector number.
+To accomplish this the current implementation assigns the number zero to
+the first source, the number one to the second source and so on until
+all interrupt sources have their unique number.
+Usually the assigned vector number equals the interrupt number mentioned
+in the documentation for a given core / CPU. This is however not true
+for the e500 cores (MPC85XX CPUs) where the documentation distinguishes
+between internal and external interrupt sources and starts counting at
+zero for both of them.
+So what to write for external interrupt source X or internal interrupt
+source Y into the device tree? Here is an example:
+The memory map for the interrupt controller in the MPC8544[0] shows,
+that the first interrupt source starts at 0x5_0000 (PIC Register Address
+Map-Interrupt Source Configuration Registers). This source becomes the
+number zero therefore:
+ External interrupt 0 = interrupt number 0
+ External interrupt 1 = interrupt number 1
+ External interrupt 2 = interrupt number 2
+ ...
+Every interrupt number allocates 0x20 bytes register space. So to get
+its number it is sufficient to shift the lower 16bits to right by five.
+So for the external interrupt 10 we have:
+ 0x0140 >> 5 = 10
+After the external sources, the internal sources follow. The in core I2C
+controller on the MPC8544 for instance has the internal source number
+27. Oo obtain its interrupt number we take the lower 16bits of its memory
+address (0x5_0560) and shift it right:
+ 0x0560 >> 5 = 43
+Therefore the I2C device node for the MPC8544 CPU has to have the
+interrupt number 43 specified in the device tree.
+[0] MPC8544E PowerQUICCTM III, Integrated Host Processor Family Reference Manual
+ MPC8544ERM Rev. 1 10/2007

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