2014-08-14 4:24 GMT+02:00 Joe.C [off-list ref]:

On Tue, 2014-08-12 at 11:02 +0200, Matthias Brugger wrote:

quoted

2014-08-11 9:15 GMT+02:00 Linus Walleij [off-list ref]:

quoted

On Thu, Jul 31, 2014 at 6:42 PM, Matthias Brugger
[off-list ref] wrote:

quoted

We enable GTP6 which ungates the arch timer clock. Apart we write the
frequency with which the timer is running in the CNTFREQ register.
In the future this should be done in the bootloader.

Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

(...)

quoted

+       if (of_machine_is_compatible("mediatek,mt6589")) {
+               /* set cntfreq register which is not done in bootloader */
+               asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (13000000));

I guess this is for something like the ARM arch timer in
drivers/clocksource/arm_arch_timer.c

Instead of doing this, use the DT property "clock-frequency" on
the ARM arch timer node, as that overrides the CP15 setting.

quoted

+
+               /* turn on GPT6 which ungates arch timer clocks */
+               gpt_base = ioremap(GPT6_CON_MT65xx, 0x04);
+       }
+
+       /* enabel clock and set to free-run */
+       if (gpt_base)
+               writel(0x31, gpt_base);

Why is this not done properly in the GPT driver (I guess
in drivers/clocksource/mtk_timer.c) instead of remapping
it and fiddling around in the machine?

I didn't put it in the GPT driver, because that would mean, that you
need to have the mtk_timer to be able to use the ARM arch timer.
From my understanding this are two independent blocks in the SoC.
Apart from that, as stated in the commit message, this patch is a
workaround until we have a bootloader which does this for us.
Therefore I thought the init_time function would be the better place to do this.

Can we have a separate node like mt6577-timerfixup then?
I'm preparing patch for mt8127 and mt8135. They all need this and use
same address and. In current form, I'll have to make this check against
a compatible string array.

The way to go is to add another of_machine_is_compatible for every
SoC. If the address is the same just use logical or.

Cheers,
Matthias

Joe.C

-- 
motzblog.wordpress.com