[PATCH] ARM: EXYNOS: reset KFC cores when cpu is up
Abhilash Kesavan
kesavan.abhilash at gmail.com
Tue Sep 1 07:47:14 PDT 2015
Hi,
On Tue, Sep 1, 2015 at 5:51 AM, Krzysztof Kozlowski
<k.kozlowski at samsung.com> wrote:
> On 01.09.2015 07:46, Javier Martinez Canillas wrote:
>>
>> [adding Krzysztof Kozlowski to cc list]
>>
>> Hello Kevin,
>>
>> On 09/01/2015 12:11 AM, Kevin Hilman wrote:
>>> Chanho Park <parkch98 at gmail.com> writes:
>>>
>>>> The cpu booting of exynos5422 has been still broken since we discussed
>>>> it in last year[1]. This patch is inspired from odroid xu3
>>>> code(Actually, it was from samsung exynos vendor kernel)[2]. This weird
>>>> reset code was founded exynos5420 octa cores series SoCs and only
>>>> required for the first boot core is the little core(kingfisher core).
>>>> Some of the exynos5420 boards and all of the exynos5422 boards will be
>>>> required this code.
>>>> There is two ways to check the little core is the first cpu. One is
>>>> checking GPG2CON[1] gpio value and the other is checking the cluster
>>>> number of the first cpu. I selected the latter because it's more easier
>>>> than the former.
>>>>
>>>> Changes since RFC[3]:
>>>> - drop checking soc_is_exynos5800 to extend this codes to
>>>> exynos5420/5422 boards.
>>>> - kfc cores will be reset only if the cpu0 is kfc core.
>>>> - Rebase top of the kukjin's for-next branch
>>>>
>>>> [1]:http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/350632.html
>>>> [2]:https://patchwork.kernel.org/patch/6782891/
>>>> [3]:http://lists.infradead.org/pipermail/linux-arm-kernel/2015-July/356610.html
>>>>
>>>> Cc: Joonyoung Shim <jy0922.shim at samsung.com>
>>>> Cc: Chanwoo Choi <cw00.choi at samsung.com>
>>>> Cc: Kevin Hilman <khilman at kernel.org>
>>>> Cc: Heesub Shin <heesub.shin at samsung.com>
>>>> Cc: Mauro Ribeiro <mauro.ribeiro at hardkernel.com>
>>>> Cc: Abhilash Kesavan <a.kesavan at samsung.com>
>>>> Cc: Przemyslaw Marczak <p.marczak at samsung.com>
>>>> Cc: Marek Szyprowski <m.szyprowski at samsung.com>
>>>> Cc: Krzysztof Kozlowski <k.kozlowski at samsung.com>
>>>> Signed-off-by: Chanho Park <parkch98 at gmail.com>
>>>
>>>> ---
>>>> arch/arm/mach-exynos/mcpm-exynos.c | 18 +++++++++++++++++-
>>>> arch/arm/mach-exynos/regs-pmu.h | 6 ++++++
>>>> 2 files changed, 23 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c
>>>> index 9bdf547..5b69ed2 100644
>>>> --- a/arch/arm/mach-exynos/mcpm-exynos.c
>>>> +++ b/arch/arm/mach-exynos/mcpm-exynos.c
>>>> @@ -20,6 +20,7 @@
>>>> #include <asm/cputype.h>
>>>> #include <asm/cp15.h>
>>>> #include <asm/mcpm.h>
>>>> +#include <asm/smp_plat.h>
>>>>
>>>> #include "regs-pmu.h"
>>>> #include "common.h"
>>>> @@ -70,7 +71,22 @@ static int exynos_cpu_powerup(unsigned int cpu, unsigned int cluster)
>>>> cluster >= EXYNOS5420_NR_CLUSTERS)
>>>> return -EINVAL;
>>>>
>>>> - exynos_cpu_power_up(cpunr);
>>>> + if (!exynos_cpu_power_state(cpunr)) {
>>>> + exynos_cpu_power_up(cpunr);
>>>> +
>>>> + /* This assumes the cluster number of the eagle is 0 and the
>>>> + * kfc is 1. When the system was booted from the kfc core,
>>>> + * they should be reset */
>>>
>>> minor: fix multi-line comment style (search for 'multi-line' in
>>> Documentation/CodingStyle)
>>>
>>> Also minor, but personally, I prefer seeing A15/A7 instead of eagle/KFC
>>> as those names are fading from my memory and I can't seem to remember
>>> which one is which. :/
>>>
>>>> + if (cluster &&
>>>> + cluster == MPIDR_AFFINITY_LEVEL(cpu_logical_map(0), 1)) {
>>>> + while (!pmu_raw_readl(S5P_PMU_SPARE2))
>>>> + udelay(10);
>>>> +
>>>> + pmu_raw_writel(EXYNOS5420_KFC_CORE_RESET(cpu),
>>>> + EXYNOS_SWRESET);
>>>> + }
>>>> + }
>>>> +
>>>> return 0;
>>>> }
>>>
>>> I tested this on top of mainline (v4.2) using exynos_defconfig (with
>>> BL_SWITCHER disabled) and I now see all 8 CPUs booting. Nice!
>>>
>>> Tested-by: Kevin Hilman <khilman at linaro.org>
>>>
>>> Also, please note that this does not fix another fundamental problem
>>> with this board in that the firmware puts CCI into secure mode, so
>>> linux/MCPM cannot manage it, causing hangs whenever CPUidle is enabled
>>> (because b.L cpuidle driver tries to use MCPM, which needs to manage
>>> CCI.)
>>>
>>> In order for this to not hang when using CPUidle, the following patch is
>>> also needed.
>>>
>>> Kevin
>>>
>>> diff --git a/arch/arm/boot/dts/exynos5422-odroidxu3.dts
>>> b/arch/arm/boot/dts/exynos5422-odroidxu3.dts
>>> index 78e6a502f320..7891bd05bf8e 100644
>>> --- a/arch/arm/boot/dts/exynos5422-odroidxu3.dts
>>> +++ b/arch/arm/boot/dts/exynos5422-odroidxu3.dts
>>> @@ -49,3 +49,11 @@
>>> shunt-resistor = <10000>;
>>> };
>>> };
>>> +
>>> +/*
>>> + * Secure firmware prevents CCI access/usage from linux, so must be
>>> disabled
>>> + * to prevent usage by MCPM.
>>> + */
>>> +&cci {
>>> + status = "disabled";
>>> +};
>>>
>>>
>>
>> I posted a similar patch that instead disabling CCI for the XU3 board,
>> it disables in exynos5422-odroidxu3-common.dtsi since all Exynos5422
>> Odroid boards have the same broken firmware and so the same issue:
>>
>> https://lkml.org/lkml/2015/8/29/59
>>
>> Krzysztof tested it on an Odroid XU3 Lite and reported that disabling
>> CCI caused some CPUs to fail to boot even with $subject applied:
>>
>> https://lkml.org/lkml/2015/8/29/65
>
> Indeed. On Odroid XU3 Chanho's patch gives me 8 CPUs up. Disabling CCI
> causes fails on CPU{5,6,7} (Cortex-A15).
Chanho's patch is for the exynos mcpm back-end. However, when we
disable CCI the mcpm code is bypassed and we default to the code in
exynos' platsmp.c/firmware.c. If the A7s were failing to boot-up then
the reason could have been that Chanho's workaround was not being
executed after applying the CCI disablement patch.
According to the comments the A15s are not booting and so the
exynos_boot_secondary function needs to be checked further.
Regards,
Abhilash
>
> Best regards,
> Krzysztof
>
>>
>> Did you succeed booting all CPUs with CONFIG_ARM_BIG_LITTLE_CPUIDLE
>> enabled and CCI disabled in the the Odroid XU3 DTS?
>>
>> Best regards,
>>
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
More information about the linux-arm-kernel
mailing list