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 ...
This commit is contained in:
42
Documentation/powerpc/dts-bindings/fsl/mpic.txt
Normal file
42
Documentation/powerpc/dts-bindings/fsl/mpic.txt
Normal file
@@ -0,0 +1,42 @@
|
||||
* 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
|
Reference in New Issue
Block a user