Re: [PATCH] ARM: EXYNOS: Fix incorrect usage of S5P_ARM_CORE1_* registers

From: Chander Kashyap
Date: Wed Jun 19 2013 - 09:24:20 EST

On 19 June 2013 18:20, Tomasz Figa <t.figa@xxxxxxxxxxx> wrote:
> On Wednesday 19 of June 2013 17:39:21 Chander Kashyap wrote:
>> On 18 June 2013 23:29, Kukjin Kim <kgene.kim@xxxxxxxxxxx> wrote:
>> > On 06/19/13 02:45, Tomasz Figa wrote:
>> >> Ccing Arnd and Olof, because I forgot to add them to git send-email...
>> >>
>> >> Sorry for the noise.
>> >>
>> >> On Tuesday 18 of June 2013 17:26:31 Tomasz Figa wrote:
>> >>> S5P_ARM_CORE1_* registers affect only core 1. To control further
>> >>> cores
>> >>> properly another registers must be used.
>> >>>
>> >>> This patch replaces S5P_ARM_CORE1_* register definitions with
>> >>> S5P_ARM_CORE_*(x) macro which return addresses of registers for
>> >>> specified core.
>> >>>
>> >>> This fixes CPU hotplug on quad core Exynos SoCs on which currently
>> >>> offlining CPUs 2 or 3 caused CPU 1 to be turned off.
>> >>
>> >> Obviously this doesn't happen currently because of the if (cpu == 1),
>> >> but>
>> > Yes, not happened...and just note exynos5440 doesn't support hotplug :)
>> > so this is available on exynos4412 and added 5420.
>> >
>> >> if logical cpu1 turned out not to be physical cpu1, then it would
>> >> crash.
>> >>
>> >> Best regards,
>> >> Tomasz
>> >>
>> >>> In addition,
>> >>> bring-up of CPU 2 and 3 is fixed on boards where bootloader powers
>> >>> off
>> >>> secondary cores by default.
>> >
>> > I need to test on board about above...
>> >
>> >>> Cc: stable@xxxxxxxxxxxxxxx
>> >>> Signed-off-by: Tomasz Figa<t.figa@xxxxxxxxxxx>
>> >>> Signed-off-by: Kyungmin Park<kyungmin.park@xxxxxxxxxxx>
>> >>> ---
>> >>>
>> >>> arch/arm/mach-exynos/hotplug.c | 9 +++++----
>> >>> arch/arm/mach-exynos/include/mach/regs-pmu.h | 10 +++++++---
>> >>> arch/arm/mach-exynos/platsmp.c | 9 +++++----
>> >>> 3 files changed, 17 insertions(+), 11 deletions(-)
>> >>>
>> >>> diff --git a/arch/arm/mach-exynos/hotplug.c
>> >>> b/arch/arm/mach-exynos/hotplug.c index af90cfa..c089943 100644
>> >>> --- a/arch/arm/mach-exynos/hotplug.c
>> >>> +++ b/arch/arm/mach-exynos/hotplug.c
>> >>> @@ -93,10 +93,11 @@ static inline void cpu_leave_lowpower(void)
>> >>>
>> >>> static inline void platform_do_lowpower(unsigned int cpu, int
>> >>>
>> >>> *spurious) {
>> >>>
>> >>> for (;;) {
>> >>>
>> >>> + void __iomem *reg_base;
>> >>> + unsigned int phys_cpu = cpu_logical_map(cpu);
>> >>>
>> >>> - /* make cpu1 to be turned off at next WFI command */
>> >>> - if (cpu == 1)
>> >>> - __raw_writel(0, S5P_ARM_CORE1_CONFIGURATION);
>> >>> + reg_base = S5P_ARM_CORE_CONFIGURATION(phys_cpu);
>>
>> Tomasz,
>> This will break for non-zero, MPIDR value. Say if MPIDR is 1 then for
>> cpu0 phys_cpu value will be 0x100,
>> and address calculation will be (S5P_ARM_CORE0_CONFIGURATION +
>> ((0x101) * 0x80)), which is wrong.
>
> Hmm, according to the code initializing __cpu_logical_map[] array this is
> not true.
>
> Here's the code:
>
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/arch/arm/kernel/setup.c?id=refs/tags/next-20130619#n468
>
> and for used macros and bitmasks:
>
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/arch/arm/include/asm/cputype.h?id=refs/tags/next-20130619#n45
>
> Now the structure of the MPIDR register:
>
> http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388e/CIHEBGFG.html
>
> As you can see, the value read from the register in
> smp_setup_processor_id() is only the physical CPU ID, so I don't see any
> problem here.
Kindly look at implementation of "arm_dt_init_cpu_maps" in
"arch/arm/kernel/devtree.c". When you pass the cpu nodes thru DT, and
cluster id is non zero, the phys_cpu will include clusterID. Say e.g
exynos4210 has CLusterID=9, hence phys_cpu value for cpu0 will be
0x901.
>
> If I'm wrong, feel free to correct me.
>
> Cc'ing people who should have more knowledge on this.
>
> Best regards,
> Tomasz
>
>> >>> + __raw_writel(0, reg_base);
>> >>>
>> >>> /*
>> >>>
>> >>> * here's the WFI
>> >>>
>> >>> @@ -106,7 +107,7 @@ static inline void platform_do_lowpower(unsigned
>> >>> int
>> >>> cpu, int *spurious)
>> >>>
>> >>> : "memory", "cc");
>> >>>
>> >>> - if (pen_release == cpu_logical_map(cpu)) {
>> >>> + if (pen_release == phys_cpu) {
>> >>>
>> >>> /*
>> >>>
>> >>> * OK, proper wakeup, we're done
>> >>> */
>> >>>
>> >>> diff --git a/arch/arm/mach-exynos/include/mach/regs-pmu.h
>> >>> b/arch/arm/mach-exynos/include/mach/regs-pmu.h index 57344b7..cf40b86
>> >>> 100644
>> >>> --- a/arch/arm/mach-exynos/include/mach/regs-pmu.h
>> >>> +++ b/arch/arm/mach-exynos/include/mach/regs-pmu.h
>> >>> @@ -125,10 +125,14 @@
>> >>>
>> >>> #define S5P_GPS_ALIVE_LOWPWR S5P_PMUREG(0x13A0)
>> >>>
>> >>> #define S5P_ARM_CORE0_CONFIGURATION S5P_PMUREG(0x2000)
>> >>>
>> >>> +#define S5P_ARM_CORE0_STATUS S5P_PMUREG(0x2004)
>> >>>
>> >>> #define S5P_ARM_CORE0_OPTION S5P_PMUREG(0x2008)
>> >>>
>> >>> -#define S5P_ARM_CORE1_CONFIGURATION S5P_PMUREG(0x2080)
>> >>> -#define S5P_ARM_CORE1_STATUS S5P_PMUREG(0x2084)
>> >>> -#define S5P_ARM_CORE1_OPTION S5P_PMUREG(0x2088)
>> >>> +#define S5P_ARM_CORE_CONFIGURATION(_nr) \
>> >>> + (S5P_ARM_CORE0_CONFIGURATION + ((_nr) * 0x80))
>> >>> +#define S5P_ARM_CORE_STATUS(_nr) \
>> >>> + (S5P_ARM_CORE0_STATUS + ((_nr) * 0x80))
>> >>> +#define S5P_ARM_CORE_OPTION(_nr) \
>> >>> + (S5P_ARM_CORE0_OPTION + ((_nr) * 0x80))
>> >>>
>> >>> #define S5P_ARM_COMMON_OPTION S5P_PMUREG(0x2408)
>> >>> #define S5P_TOP_PWR_OPTION S5P_PMUREG(0x2C48)
>> >>>
>> >>> diff --git a/arch/arm/mach-exynos/platsmp.c
>> >>> b/arch/arm/mach-exynos/platsmp.c index d9c6d0a..2cbabc8 100644
>> >>> --- a/arch/arm/mach-exynos/platsmp.c
>> >>> +++ b/arch/arm/mach-exynos/platsmp.c
>> >>> @@ -109,14 +109,15 @@ static int __cpuinit
>> >>> exynos_boot_secondary(unsigned int cpu, struct task_struct */
>> >>>
>> >>> write_pen_release(phys_cpu);
>> >>>
>> >>> - if (!(__raw_readl(S5P_ARM_CORE1_STATUS)&
>> >>> S5P_CORE_LOCAL_PWR_EN))>>
>> >> {
>> >>
>> >>> + if (!(__raw_readl(S5P_ARM_CORE_STATUS(phys_cpu))
>> >>> + & S5P_CORE_LOCAL_PWR_EN)) {
>> >>>
>> >>> __raw_writel(S5P_CORE_LOCAL_PWR_EN,
>> >>>
>> >>> - S5P_ARM_CORE1_CONFIGURATION);
>> >>> + S5P_ARM_CORE_CONFIGURATION(phys_cpu));
>> >>>
>> >>> timeout = 10;
>> >>>
>> >>> /* wait max 10 ms until cpu1 is on */
>> >>>
>> >>> - while ((__raw_readl(S5P_ARM_CORE1_STATUS)
>> >>> + while ((__raw_readl(S5P_ARM_CORE_STATUS(phys_cpu))
>>
>> Ditto
>>
>> >>> & S5P_CORE_LOCAL_PWR_EN) !=
>> >>>
>> >>> S5P_CORE_LOCAL_PWR_EN)
>> >>
>> >> {
>> >>
>> >>> if (timeout-- == 0)
>> >>>
>> >>> break;
>> >>>
>> >>> @@ -125,7 +126,7 @@ static int __cpuinit
>> >>> exynos_boot_secondary(unsigned
>> >>> int cpu, struct task_struct }
>> >>>
>> >>> if (timeout == 0) {
>> >>>
>> >>> - printk(KERN_ERR "cpu1 power enable failed");
>> >>> + printk(KERN_ERR "cpu%u power enable failed",
>> >>> cpu);
>> >>>
>> >>> spin_unlock(&boot_lock);
>> >>> return -ETIMEDOUT;
>> >>>
>> >>> }
>> >>
>> >> --
>> >
>> > --
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>>
>> --
>> with warm regards,
>> Chander Kashyap
>> --
>> To unsubscribe from this list: send the line "unsubscribe
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--
with warm regards,
Chander Kashyap
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