Re: [PATCH v2 1/2] powerpc/mpic: Add Open-PIC global timer document
From: Scott Wood <hidden>
Date: 2012-08-10 19:21:45
Also in:
linuxppc-dev
Possibly related (same subject, not in this thread)
- 2012-08-17 · RE: [PATCH v2 1/2] powerpc/mpic: Add Open-PIC global timer document · Wang Dongsheng-B40534 <hidden>
- 2012-08-14 · Re: [PATCH v2 1/2] powerpc/mpic: Add Open-PIC global timer document · Scott Wood <hidden>
- 2012-08-13 · RE: [PATCH v2 1/2] powerpc/mpic: Add Open-PIC global timer document · Wang Dongsheng-B40534 <hidden>
- 2012-08-10 · Re: [PATCH v2 1/2] powerpc/mpic: Add Open-PIC global timer document · Gala Kumar-B11780 <hidden>
- 2012-08-10 · [PATCH v2 1/2] powerpc/mpic: Add Open-PIC global timer document · <hidden>
On 08/10/2012 12:53 AM, Dongsheng.wang-KZfg59tc24xl57MIdRCFDg@public.gmane.org wrote:
quoted hunk
From: Wang Dongsheng <redacted> Add a description of the OPEN-PIC global timer in the OPEN-PIC document. Moidfy mpic-timer document. 1.Add a TFRR register region. This register is written by software to report the clocking frequency of the PIC timers. 2.Add a device_type. The global timer in line with the OPEN-PIC specification. Signed-off-by: Wang Dongsheng <redacted> Signed-off-by: Li Yang <redacted> --- Documentation/devicetree/bindings/open-pic.txt | 46 ++++++++++++++++++++ .../devicetree/bindings/powerpc/fsl/mpic-timer.txt | 21 +++++---- arch/powerpc/boot/dts/fsl/pq3-mpic-timer-B.dtsi | 7 ++- arch/powerpc/boot/dts/fsl/pq3-mpic.dtsi | 7 ++- 4 files changed, 66 insertions(+), 15 deletions(-)diff --git a/Documentation/devicetree/bindings/open-pic.txt b/Documentation/devicetree/bindings/open-pic.txt index 909a902..045c2e9 100644 --- a/Documentation/devicetree/bindings/open-pic.txt +++ b/Documentation/devicetree/bindings/open-pic.txt@@ -92,6 +92,52 @@ Example 2: * References +* Open PIC global timers + +Required properties: +- compatible: "open-pic,global-timer"
open-pic isn't a vendor (or software project that acts like a pseudo-vendor) -- I'd go with "open-pic-global-timer".
+- reg : Contains two regions. The first is the timer frequency reporting + register for the group. The second is the main timer register bank + (GTCCR, GTBCR, GTVPR, GTDR).
Why not just put clock-frequency in the node, instead of describing TFRR? I don't think U-Boot currently sets TFRR.
+- available-ranges: use <start count> style section to define which
+ timer interrupts can be used. This property is optional; without this,
+ all timers within the group can be used.
+
+- interrupts: one interrupt per timer in the group, in order, starting
+ with timer zero. If available-ranges is present, only the interrupts
+ that correspond to available timers shall be present.
+
+* Examples
+
+Example 1:
+
+ /* Note that this requires #interrupt-cells to be 4 */
+ timer: timer@010f0 {Unit addres shouldn't have leading zeroes.
+ compatible = "open-pic,global-timer"; + device_type = "open-pic";
Remove device_type. Not only is it deprecated outside of real OF, it's wrong -- this isn't an openpic, it's just a subset of it.
+ reg = <0x010f0 4 0x01100 0x100>;
+
+ /* Another AMP partition is using timer */
+ available-ranges = <2 2>;
+
+ interrupts = <2 0 3 0
+ 3 0 3 0>;
+ };
+
+Example 2:
+
+ timer: timer@010f0 {
+ compatible = "open-pic,global-timer";
+ device_type = "open-pic";
+ reg = <0x010f0 4 0x01100 0x100>;
+ interrupts = <0 0 3 0
+ 1 0 3 0
+ 2 0 3 0
+ 3 0 3 0>;
+ };4-cell interrupt specifiers are specific to Freescale MPICs. This means there's no way to describe the timer interrupt on a non-Freescale openpic. Again, I suggest we not bother with this in the absence of an actual need to support the timer on non-Freescale openpic in partitioned scenarios. The existing openpic node is sufficient to describe the hardware in the absence of partitioning. We could have an "openpic-no-timer" property to indicate that we're describing it separately, so that the absence of a timer node isn't ambiguous as to whether it's an old tree or a partitioned scenario. An fsl,mpic compatible would imply openpic-no-timer. Note that I believe many of the non-Freescale openpic nodes are going to be found on systems with real Open Firmware, so we can't go changing the device tree for them. -Scott