mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-28 03:35:27 +07:00
5983255659
This patch updates description of device tree bindings for Exynos MCT (multicore timers). Namely: - added note about simplified specification of local timer interrupts, when using single per-processor interrupt for all local timers, - changed first example that was incorrectly suggesting that global timer interrupts are optional, - simplified example interrupt map, - added example showing simplified local timer interrupt specification. Signed-off-by: Tomasz Figa <t.figa@samsung.com> Acked-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
89 lines
3.0 KiB
Plaintext
89 lines
3.0 KiB
Plaintext
Samsung's Multi Core Timer (MCT)
|
|
|
|
The Samsung's Multi Core Timer (MCT) module includes two main blocks, the
|
|
global timer and CPU local timers. The global timer is a 64-bit free running
|
|
up-counter and can generate 4 interrupts when the counter reaches one of the
|
|
four preset counter values. The CPU local timers are 32-bit free running
|
|
down-counters and generate an interrupt when the counter expires. There is
|
|
one CPU local timer instantiated in MCT for every CPU in the system.
|
|
|
|
Required properties:
|
|
|
|
- compatible: should be "samsung,exynos4210-mct".
|
|
(a) "samsung,exynos4210-mct", for mct compatible with Exynos4210 mct.
|
|
(b) "samsung,exynos4412-mct", for mct compatible with Exynos4412 mct.
|
|
|
|
- reg: base address of the mct controller and length of the address space
|
|
it occupies.
|
|
|
|
- interrupts: the list of interrupts generated by the controller. The following
|
|
should be the order of the interrupts specified. The local timer interrupts
|
|
should be specified after the four global timer interrupts have been
|
|
specified.
|
|
|
|
0: Global Timer Interrupt 0
|
|
1: Global Timer Interrupt 1
|
|
2: Global Timer Interrupt 2
|
|
3: Global Timer Interrupt 3
|
|
4: Local Timer Interrupt 0
|
|
5: Local Timer Interrupt 1
|
|
6: ..
|
|
7: ..
|
|
i: Local Timer Interrupt n
|
|
|
|
For MCT block that uses a per-processor interrupt for local timers, such
|
|
as ones compatible with "samsung,exynos4412-mct", only one local timer
|
|
interrupt might be specified, meaning that all local timers use the same
|
|
per processor interrupt.
|
|
|
|
Example 1: In this example, the IP contains two local timers, using separate
|
|
interrupts, so two local timer interrupts have been specified,
|
|
in addition to four global timer interrupts.
|
|
|
|
mct@10050000 {
|
|
compatible = "samsung,exynos4210-mct";
|
|
reg = <0x10050000 0x800>;
|
|
interrupts = <0 57 0>, <0 69 0>, <0 70 0>, <0 71 0>,
|
|
<0 42 0>, <0 48 0>;
|
|
};
|
|
|
|
Example 2: In this example, the timer interrupts are connected to two separate
|
|
interrupt controllers. Hence, an interrupt-map is created to map
|
|
the interrupts to the respective interrupt controllers.
|
|
|
|
mct@101C0000 {
|
|
compatible = "samsung,exynos4210-mct";
|
|
reg = <0x101C0000 0x800>;
|
|
interrupt-parent = <&mct_map>;
|
|
interrupts = <0>, <1>, <2>, <3>, <4>, <5>;
|
|
|
|
mct_map: mct-map {
|
|
#interrupt-cells = <1>;
|
|
#address-cells = <0>;
|
|
#size-cells = <0>;
|
|
interrupt-map = <0 &gic 0 57 0>,
|
|
<1 &gic 0 69 0>,
|
|
<2 &combiner 12 6>,
|
|
<3 &combiner 12 7>,
|
|
<4 &gic 0 42 0>,
|
|
<5 &gic 0 48 0>;
|
|
};
|
|
};
|
|
|
|
Example 3: In this example, the IP contains four local timers, but using
|
|
a per-processor interrupt to handle them. Either all the local
|
|
timer interrupts can be specified, with the same interrupt specifier
|
|
value or just the first one.
|
|
|
|
mct@10050000 {
|
|
compatible = "samsung,exynos4412-mct";
|
|
reg = <0x10050000 0x800>;
|
|
|
|
/* Both ways are possible in this case. Either: */
|
|
interrupts = <0 57 0>, <0 69 0>, <0 70 0>, <0 71 0>,
|
|
<0 42 0>;
|
|
/* or: */
|
|
interrupts = <0 57 0>, <0 69 0>, <0 70 0>, <0 71 0>,
|
|
<0 42 0>, <0 42 0>, <0 42 0>, <0 42 0>;
|
|
};
|