[PATCH 2/2] clocksource: add rockchip-specific armv7-timer setup

[Matthias Brugger]

2014-06-20 12:51 GMT+02:00 Mark Rutland <mark.rutland at arm.com>:
> On Fri, Jun 20, 2014 at 11:44:49AM +0100, Heiko Stübner wrote:
>> The armv7-timer on Rockchip RK3288 SoCs needs an underlying timer to run.
>> Therefore the special rockchip,rk3288-armv7-timer does this setup and
>> then initializes the architected timer using the new locally exposed
>> arch_timer_init.
>>
>> Suggested-by: Arnd Bergmann <arnd at arndb.de>
>> Signed-off-by: Heiko Stuebner <heiko at sntech.de>
>> ---
>>  .../bindings/arm/rockchip/armv7-timer.txt          | 22 +++++++++
>>  drivers/clocksource/Makefile                       |  1 +
>>  drivers/clocksource/rockchip_timer.c               | 57 ++++++++++++++++++++++
>>  3 files changed, 80 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/arm/rockchip/armv7-timer.txt
>>  create mode 100644 drivers/clocksource/rockchip_timer.c
>>
>> diff --git a/Documentation/devicetree/bindings/arm/rockchip/armv7-timer.txt b/Documentation/devicetree/bindings/arm/rockchip/armv7-timer.txt
>> new file mode 100644
>> index 0000000..4c1950a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/rockchip/armv7-timer.txt
>> @@ -0,0 +1,22 @@
>> +Rockchip armv7-timer:
>> +---------------------
>> +
>> +The architected timer on rk3288 SoCs has special setup requirements, as
>> +the cpu-timer block needs to supply the architected timer.
>> +
>> +Required node properties:
>> +- compatible value : = "rockchip,rk3288-armv7-timer";
>> +- reg : physical base address and the size of the registers window
>> +        of the supplying timer block
>> +- CP15 Timer node properties as described in bindings/arm/arch_timer.txt
>> +
>> +Example:
>> +
>> +architected-timer {
>> +     compatible = "rockchip,rk3288-armv7-timer";
>> +     reg = <0xff810020 0x20>;
>> +     interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>,
>> +                  <GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>,
>> +                  <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>;
>> +     clock-frequency = <24000000>;
>> +};
>> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
>> index 800b130..cbad225 100644
>> --- a/drivers/clocksource/Makefile
>> +++ b/drivers/clocksource/Makefile
>> @@ -20,6 +20,7 @@ obj-$(CONFIG_ARCH_MARCO)    += timer-marco.o
>>  obj-$(CONFIG_ARCH_MOXART)    += moxart_timer.o
>>  obj-$(CONFIG_ARCH_MXS)               += mxs_timer.o
>>  obj-$(CONFIG_ARCH_PRIMA2)    += timer-prima2.o
>> +obj-$(CONFIG_ARCH_ROCKCHIP)  += rockchip_timer.o
>>  obj-$(CONFIG_ARCH_U300)              += timer-u300.o
>>  obj-$(CONFIG_SUN4I_TIMER)    += sun4i_timer.o
>>  obj-$(CONFIG_SUN5I_HSTIMER)  += timer-sun5i.o
>> diff --git a/drivers/clocksource/rockchip_timer.c b/drivers/clocksource/rockchip_timer.c
>> new file mode 100644
>> index 0000000..46c2146
>> --- /dev/null
>> +++ b/drivers/clocksource/rockchip_timer.c
>> @@ -0,0 +1,57 @@
>> +/*
>> + * Copyright (c) 2014 MundoReader S.L.
>> + * Author: Heiko Stuebner <heiko at sntech.de>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#include <linux/init.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/clockchips.h>
>> +#include "arm_arch_timer.h"
>> +
>> +#define TIMER_LOAD_COUNT0            0x00
>> +#define TIMER_LOAD_COUNT1            0x04
>> +#define TIMER_CURRENT_VALUE0         0x08
>> +#define TIMER_CURRENT_VALUE1         0x0c
>> +#define TIMER_CONTROL_REG            0x10
>> +#define TIMER_INT_STATUS             0x18
>> +
>> +#define TIMER_DISABLE                        (0 << 0)
>> +#define TIMER_ENABLE                 (1 << 0)
>> +#define TIMER_MODE_FREE_RUNNING              (0 << 1)
>> +#define TIMER_MODE_USER_DEFINED_COUNT        (1 << 1)
>> +#define TIMER_INT_MASK                       (0 << 2)
>> +#define TIMER_INT_UNMASK             (1 << 2)
>> +
>> +static __init void rk3288_arch_timer_init(struct device_node *np)
>> +{
>> +     void __iomem *reg_base;
>> +
>> +     reg_base = of_io_request_and_map(np, 0, "rk3288-armv7-timer");
>> +     if (!reg_base) {
>> +             pr_warn("%s: Can't get resource\n", __func__);
>> +             return;
>> +     }
>> +
>> +     writel(TIMER_DISABLE, reg_base + TIMER_CONTROL_REG);
>> +
>> +     writel(0xffffffff, reg_base + TIMER_LOAD_COUNT0);
>> +     writel(0xffffffff, reg_base + TIMER_LOAD_COUNT1);
>> +
>> +     writel(TIMER_ENABLE | TIMER_MODE_FREE_RUNNING,
>> +            reg_base + TIMER_CONTROL_REG);
>
> Given that this is unconditionally set up in this way, could this not be
> done in the fimrware/bootloader?

IMHO this is a candidate for the init_time function of the machine
description file until we have a bootloader that enables the arm arch
timer properly.

>
> That way you could also setup CNTFREQ correctly, and virtualisation can
> just work out of the box.

Setting CNTFREQ as done in mach-shmobile [0] does not help here, right?

Regards,
Matthias

[0] http://lxr.free-electrons.com/source/arch/arm/mach-shmobile/setup-rcar-gen2.c#L77

>
> This looks like a clock driver in disguise...
>
> Mark.



-- 
motzblog.wordpress.com