On 09.02.19 18:35, Marek Vasut wrote:
Hi
On 2/7/19 6:19 PM, Oleksandr wrote:
[...]
+ /* Update registers with correct frequency */
+ writel(freq, TIMER_BASE + TIMER_CNTFID0);
+ asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
+
+ /* Make sure arch timer is started by setting bit 0 of
CNTCR */
+ writel(1, TIMER_BASE + TIMER_CNTCR);
Shouldn't this be in the timer driver instead ?
Which timer driver? Probably, I missed something, but I didn't find any
arch timer driver being used for Gen2.
I see that TMU timer (arch/sh/lib/time.c) is used as a system timer, but
it is yet another IP.
Would it be correct, if I move arch timer updating code to
arch/arm/mach-rmobile directory?
Actually, at the same location the corresponding code lives in Linux:
https://elixir.bootlin.com/linux/v5.0-rc5/source/arch/arm/mach-shmobile/setup-rcar-gen2.c#L61
Presumably if this is something else than TMU, it needs proper driver
that goes into drivers/ .
Did I get your point correctly that new driver (specially for Gen2 arch
timer) should be introduced in U-Boot and
the only one thing it is intended to do is to configure that timer for
the future use by Linux/Hypervisor?
If yes, the only question I have is how that new driver is going to be
populated? There is no corresponding node for arch timer in the device
tree.
https://elixir.bootlin.com/linux/v5.0-rc5/source/arch/arm/boot/dts/r8a7790.dtsi
So, do I need specially for this case add arch timer node with reg and
compatible properties?
Sorry if I ask obvious questions, not familiar enough with U-Boot.
You would need a DT entry and a bit of code to start the timer in case
the PSCI is enabled, yes. This would then fit into the DM/DT paradigm.
I understand your point, thank you.
Will create a simple driver for arch timer in V2.
+ }
+}
+
+/*
+ * In order not to break compilation if someone decides to build
with PSCI
+ * support disabled, keep these dummy functions.
+ */
That's currently the only use-case.
Shall I drop this comment and dummy functions below?
Since there is no PSCI support, yes.
Understand.
[...]
I'd like to have a cover letter go with V2, which describes what you're
trying to achieve here.
Yes, sure. Cover letter is present for the current V1 as well.
I thought that I had CC-ed all.
This is a link to it:
http://u-boot.10912.n7.nabble.com/PATCH-0-3-PSCI-support-for-r8a7790-SoC-Lager-Stout-boards-td357352.html
Thanks
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