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author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-22 17:18:13 -0500 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-22 17:18:13 -0500 |
commit | dd508ae2dbff0cfc7401eb6e278339fc56bc5033 (patch) | |
tree | daa9f88a4e2e65e86b351ffa2d52dcc07e753c1e /Documentation | |
parent | 7801edb0b8b66e83c13623b483bc2e846c007c9d (diff) | |
parent | 95cd34b42b43c0ed5a89a764e023189bfe7b1530 (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')
-rw-r--r-- | Documentation/powerpc/dts-bindings/fsl/mpic.txt | 42 |
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 new file mode 100644 index 000000000000..71e39cf3215b --- /dev/null +++ b/Documentation/powerpc/dts-bindings/fsl/mpic.txt | |||
@@ -0,0 +1,42 @@ | |||
1 | * OpenPIC and its interrupt numbers on Freescale's e500/e600 cores | ||
2 | |||
3 | The OpenPIC specification does not specify which interrupt source has to | ||
4 | become which interrupt number. This is up to the software implementation | ||
5 | of the interrupt controller. The only requirement is that every | ||
6 | interrupt source has to have an unique interrupt number / vector number. | ||
7 | To accomplish this the current implementation assigns the number zero to | ||
8 | the first source, the number one to the second source and so on until | ||
9 | all interrupt sources have their unique number. | ||
10 | Usually the assigned vector number equals the interrupt number mentioned | ||
11 | in the documentation for a given core / CPU. This is however not true | ||
12 | for the e500 cores (MPC85XX CPUs) where the documentation distinguishes | ||
13 | between internal and external interrupt sources and starts counting at | ||
14 | zero for both of them. | ||
15 | |||
16 | So what to write for external interrupt source X or internal interrupt | ||
17 | source Y into the device tree? Here is an example: | ||
18 | |||
19 | The memory map for the interrupt controller in the MPC8544[0] shows, | ||
20 | that the first interrupt source starts at 0x5_0000 (PIC Register Address | ||
21 | Map-Interrupt Source Configuration Registers). This source becomes the | ||
22 | number zero therefore: | ||
23 | External interrupt 0 = interrupt number 0 | ||
24 | External interrupt 1 = interrupt number 1 | ||
25 | External interrupt 2 = interrupt number 2 | ||
26 | ... | ||
27 | Every interrupt number allocates 0x20 bytes register space. So to get | ||
28 | its number it is sufficient to shift the lower 16bits to right by five. | ||
29 | So for the external interrupt 10 we have: | ||
30 | 0x0140 >> 5 = 10 | ||
31 | |||
32 | After the external sources, the internal sources follow. The in core I2C | ||
33 | controller on the MPC8544 for instance has the internal source number | ||
34 | 27. Oo obtain its interrupt number we take the lower 16bits of its memory | ||
35 | address (0x5_0560) and shift it right: | ||
36 | 0x0560 >> 5 = 43 | ||
37 | |||
38 | Therefore the I2C device node for the MPC8544 CPU has to have the | ||
39 | interrupt number 43 specified in the device tree. | ||
40 | |||
41 | [0] MPC8544E PowerQUICCTM III, Integrated Host Processor Family Reference Manual | ||
42 | MPC8544ERM Rev. 1 10/2007 | ||