[PATCH 3/5] ARM: Exynos: add device tree support for MCT controller driver
Thomas Abraham
thomas.abraham at linaro.org
Mon Nov 5 18:46:42 EST 2012
Hi Sylwester,
Thanks for your comments.
On 3 November 2012 22:20, Sylwester Nawrocki
<sylvester.nawrocki at gmail.com> wrote:
> Hi Thomas,
>
>
> On 11/03/2012 03:45 PM, Thomas Abraham wrote:
>>
>> Allow the MCT controller base address and interrupts to be obtained from
>> device tree and remove unused static definitions of these. The non-dt
>> support
>> for Exynos5250 is removed but retained for Exynos4210 based platforms.
>>
>> Cc: Changhwan Youn<chaos.youn at samsung.com>
>> Signed-off-by: Thomas Abraham<thomas.abraham at linaro.org>
>> ---
>> .../bindings/timer/samsung,exynos4210-mct.txt | 70
>> ++++++++++++++++++++
>> arch/arm/mach-exynos/include/mach/irqs.h | 6 --
>> arch/arm/mach-exynos/mct.c | 42 ++++++++----
>> 3 files changed, 99 insertions(+), 19 deletions(-)
>> create mode 100644
>> Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
>>
>> diff --git
>> a/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
>> b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
>> new file mode 100644
>> index 0000000..c53fd93
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
>> @@ -0,0 +1,70 @@
>> +Samsung's Multi Core Timer (MCT)
>> +
>> +The Samsung's Multi Core Timer (MCT) module includes two main blocks, the
>> +global timer and CPU local timers. The global timer is a 64-bit free
>> running
>> +up-counter and can generate 4 interrupts when the counter reaches one of
>> the
>> +four preset counter values. The CPU local timers are 32-bit free running
>> +down-counters and generates an interrupt when the counter expires. There
>> is
>
>
> s/generates/generate ?
Ok.
>
>
>> +one CPU local timer instantiated in MCT for every CPU in the system.
>> +
>> +Required properties:
>> +
>> +- compatible: should be "samsung,exynos4210-mct".
>> +- reg: base address of the mct controller and length of the address space
>> + it occupies.
>> +- interrupts: the list of interrupts generated by the controller. The
>> following
>> + should be the order of the interrupts specified. The local timer
>> interrupts
>> + should be specified after the four global timer interrupts have been
>> + specified.
>> +
>> + 0: Global Timer Interrupt 0
>> + 1: Global Timer Interrupt 1
>> + 2: Global Timer Interrupt 2
>> + 3: Global Timer Interrupt 3
>> + 4: Local Timer Interrupt 0
>> + 5: Local Timer Interrupt 1
>> + 6: ..
>> + 7: ..
>> + i: Local Timer Interrupt n
>> +
>> +- samsung,mct-nr-local-irqs: The number of local timer interrupts
>> supported
>> + by the MCT controller.
>> +
>> +Example 1: In this example, the system uses only the first global timer
>> + interrupt generated by MCT and the remaining three global timer
>> + interrupts are unused. Two local timer interrupts have been
>> + specified.
>> +
>> + mct at 10050000 {
>> + compatible = "samsung,exynos4210-mct";
>> + reg =<0x10050000 0x800>;
>> + interrupts =<0 57 0>,<0 0 0>,<0 0 0>,<0 0 0>,
>> + <0 42 0>,<0 48 0>;
>> + samsung,mct-nr-local-irqs =<4>;
>
>
> Then this means the MCT supports 4 local interrupts but only 2 are
> specified here ? Doesn't the code below expect
>
> samsung,mct-nr-local-irqs = <2>;
>
> in this case ? Or should interrupts really be
>
>
> interrupts =<0 57 0>, <0 0 0>, <0 0 0>, <0 0 0>,
> <0 42 0>, <0 48 0>, <0 0 0>, <0 0 0>;
>
> ?
No, that was a typo. It should be samsung,mct-nr-local-irqs = <2>.
Thanks for spotting this.
>>
>> + };
>> +
>> +Example 2: In this example, the MCT global and local timer interrupts are
>> + connected to two seperate interrupt controllers. Hence, an
>> + interrupt-map is created to map the interrupts to the
>> respective
>> + interrupt controllers.
>> +
>> + mct at 101C0000 {
>> + compatible = "samsung,exynos4210-mct";
>> + reg =<0x101C0000 0x800>;
>> + interrupt-controller;
>> + #interrups-cells =<2>;
>> + interrupt-parent =<&mct_map>;
>> + interrupts =<0 0>,<1 0>,<2 0>,<3 0>,
>> + <4 0>,<5 0>;
>> + samsung,mct-nr-local-irqs =<2>;
>
>
> Here the samsung,mct-nr-local-irqs' value matches what's specified in the
> interrupts property.
>
>
>> +
>> + mct_map: mct-map {
>> + compatible = "samsung,mct-map";
>
>
> Do we need a compatible property in sub-nodes like this one ?
> Wouldn't it be sufficient to reference this node, for example by name ?
Yes, it is not really required. I will remove it.
>
>> + #interrupt-cells =<2>;
>> + #address-cells =<0>;
>> + #size-cells =<0>;
>> + interrupt-map =<0x0 0&combiner 23 3>,
>> + <0x4 0&gic 0 120 0>,
>> + <0x5 0&gic 0 121 0>;
>>
>> + };
>> + };
>> diff --git a/arch/arm/mach-exynos/include/mach/irqs.h
>> b/arch/arm/mach-exynos/include/mach/irqs.h
>> index 6da3115..03c9f04 100644
>> --- a/arch/arm/mach-exynos/include/mach/irqs.h
>> +++ b/arch/arm/mach-exynos/include/mach/irqs.h
>> @@ -30,8 +30,6 @@
>>
>> /* For EXYNOS4 and EXYNOS5 */
>>
>> -#define EXYNOS_IRQ_MCT_LOCALTIMER IRQ_PPI(12)
>> -
>> #define EXYNOS_IRQ_EINT16_31 IRQ_SPI(32)
>>
>> /* For EXYNOS4 SoCs */
>> @@ -320,8 +318,6 @@
>> #define EXYNOS5_IRQ_CEC IRQ_SPI(114)
>> #define EXYNOS5_IRQ_SATA IRQ_SPI(115)
>>
>> -#define EXYNOS5_IRQ_MCT_L0 IRQ_SPI(120)
>> -#define EXYNOS5_IRQ_MCT_L1 IRQ_SPI(121)
>> #define EXYNOS5_IRQ_MMC44 IRQ_SPI(123)
>> #define EXYNOS5_IRQ_MDMA1 IRQ_SPI(124)
>> #define EXYNOS5_IRQ_FIMC_LITE0 IRQ_SPI(125)
>> @@ -411,8 +407,6 @@
>> #define EXYNOS5_IRQ_PMU_CPU1 COMBINER_IRQ(22, 4)
>>
>> #define EXYNOS5_IRQ_EINT0 COMBINER_IRQ(23, 0)
>> -#define EXYNOS5_IRQ_MCT_G0 COMBINER_IRQ(23, 3)
>> -#define EXYNOS5_IRQ_MCT_G1 COMBINER_IRQ(23, 4)
>>
>> #define EXYNOS5_IRQ_EINT1 COMBINER_IRQ(24, 0)
>> #define EXYNOS5_IRQ_SYSMMU_LITE1_0 COMBINER_IRQ(24, 1)
>> diff --git a/arch/arm/mach-exynos/mct.c b/arch/arm/mach-exynos/mct.c
>> index d65d0c7..f7792b8 100644
>> --- a/arch/arm/mach-exynos/mct.c
>> +++ b/arch/arm/mach-exynos/mct.c
>> @@ -19,6 +19,9 @@
>> #include<linux/platform_device.h>
>> #include<linux/delay.h>
>> #include<linux/percpu.h>
>> +#include<linux/of.h>
>> +#include<linux/of_irq.h>
>> +#include<linux/of_address.h>
>>
>> #include<asm/hardware/gic.h>
>> #include<asm/localtimer.h>
>> @@ -483,14 +486,16 @@ static struct local_timer_ops exynos4_mct_tick_ops
>> __cpuinitdata = {
>> };
>> #endif /* CONFIG_LOCAL_TIMERS */
>>
>> -static void __init exynos4_timer_resources(void)
>> +static void __init exynos4_timer_resources(struct device_node *np)
>> {
>> struct clk *mct_clk;
>> mct_clk = clk_get(NULL, "xtal");
>>
>> clk_rate = clk_get_rate(mct_clk);
>>
>> - reg_base = S5P_VA_SYSTIMER;
>> + reg_base = (np) ? of_iomap(np, 0) : S5P_VA_SYSTIMER;
>
>
> nit: Parentheses around np look redundant.
Ok.
>
>
>> + if (!reg_base)
>> + panic("%s: unable to ioremap mct address space\n",
>> __func__);
>
>
> How about adding a line like:
>
> #define pr_fmt(fmt) "%s: " fmt, __func__
>
> on top of this file and dropping "%s: " and __func__ in those panic() calls
> ? It would make the logs more consistent across whole file.
Ok.
>
>
>> #ifdef CONFIG_LOCAL_TIMERS
>> if (mct_int_type == MCT_INT_PPI) {
>> @@ -509,23 +514,34 @@ static void __init exynos4_timer_resources(void)
>>
>> static void __init exynos4_timer_init(void)
>> {
>> - if (soc_is_exynos4210()) {
>> + struct device_node *np;
>> + u32 nr_irqs, i;
>> +
>> + np = of_find_compatible_node(NULL, NULL,
>> "samsung,exynos4210-mct");
>> + if (np) {
>> + if (of_machine_is_compatible("samsung,exynos4210") ||
>> + of_machine_is_compatible("samsung,exynos5250"))
>> + mct_int_type = MCT_INT_SPI;
>> + else
>> + mct_int_type = MCT_INT_PPI;
>
>
> Does it make sense to specify this mct_int_type as a property of
> the mct node ?
The MCT bindings are independent of the system integration details.
There could be a system that uses MCT controller but not GIC
controller.
Thanks,
Thomas.
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