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Message-ID: <CABuKBe+0HRCg_gK2r60vS-wKCe7dCT5CzVn5-ck4feM-+aUR4g@mail.gmail.com> Date: Thu, 14 Aug 2014 11:35:56 +0200 From: Matthias Brugger <matthias.bgg@...il.com> To: "Joe.C" <srv_yingjoe.chen@...iatek.com> Cc: Linus Walleij <linus.walleij@...aro.org>, Mark Rutland <mark.rutland@....com>, Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>, Russell King - ARM Linux <linux@....linux.org.uk>, Arnd Bergmann <arnd@...db.de>, Pawel Moll <pawel.moll@....com>, "ijc+devicetree@...lion.org.uk" <ijc+devicetree@...lion.org.uk>, Heiko Stübner <heiko@...ech.de>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, stefan@...er.ch, Stephen Warren <swarren@...dia.com>, "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>, Rob Herring <robh+dt@...nel.org>, "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>, Kumar Gala <galak@...eaurora.org>, Olof Johansson <olof@...om.net>, Mike Turquette <mturquette@...aro.org>, Maxime Ripard <maxime.ripard@...e-electrons.com>, Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>, "Berg, Anders" <anders.berg@....com>, Jason Cooper <jason@...edaemon.net> Subject: Re: [PATCH 6/7] arm: mediatek: enable gpt6 on boot up to make arch timer working 2014-08-14 4:24 GMT+02:00 Joe.C <srv_yingjoe.chen@...iatek.com>: > On Tue, 2014-08-12 at 11:02 +0200, Matthias Brugger wrote: >> 2014-08-11 9:15 GMT+02:00 Linus Walleij <linus.walleij@...aro.org>: >> > On Thu, Jul 31, 2014 at 6:42 PM, Matthias Brugger >> > <matthias.bgg@...il.com> wrote: >> > >> >> 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@...il.com> >> > (...) >> > >> >> + 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. >> > >> >> + >> >> + /* 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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