[U-Boot] [PATCH] arm: exynos: Use the generic lowlevel_init instead of the specific one
Alison Wang
alison.wang at nxp.com
Wed Nov 16 08:43:34 CET 2016
Hi, Thomas,
I didn't see your patch. Maybe it isn't CC'ing me. Could you send me and york the link?
Minkyu Kang,
Could you add review-by and assign this patch http://patchwork.ozlabs.org/patch/667948/ to York? So he can merge this patch and Thomas's patch together.
Thanks.
Best Regards,
Alison Wang
> > On Tue, Nov 15, 2016 at 1:03 PM, Alison Wang <alison.wang at nxp.com>
> > wrote:
> > > Hi, Thomas, Alex and York,
> > >
> > > Before there are some discussions about this patch, could we make a
> > solution now? Or else, the patches about [PATCH v8 0/3] armv8:
> Support
> > loading 32-bit OS in AArch32 execution state can't be merged, as the
> > compiling will fail without this patch.
> > >
> > > Thomas, is ARMV8_MULTIENTRY enabled on Exynos7420 now? If not, is
> > there a good way to enable ARMV8_MULTIENTRY on Exynos7420 now?
> >
> > It is not yet enabled. I will post the ARMV8_MULTIENTRY enable patch
> > for Exynos7420 later today. Alternatively, you could include the
> patch
> > listed in the previous email in your series.
> >
> [Alison Wang] Thanks for your reply. I think it's better to send the
> patch by you (the maintainer). Please send it later today. :)
>
> > >
> > > Thanks.
> > >
> > > Best Regards,
> > > Alison Wang
> > >
> > >> -----Original Message-----
> > >> From: Thomas Abraham [mailto:ta.omasab at gmail.com]
> > >> Sent: Tuesday, September 20, 2016 4:45 PM
> > >> To: Alexander Graf <agraf at suse.de>
> > >> Cc: Alison Wang <b18965 at freescale.com>; thomas.ab at samsung.com;
> > Minkyu
> > >> Kang <mk7.kang at samsung.com>; york sun <york.sun at nxp.com>; U-Boot
> > >> Mailing List <u-boot at lists.denx.de>; Jason Jin <jason.jin at nxp.com>
> > >> Subject: Re: [U-Boot] [PATCH] arm: exynos: Use the generic
> > >> lowlevel_init instead of the specific one
> > >>
> > >> On Tue, Sep 20, 2016 at 12:03 PM, Alexander Graf <agraf at suse.de>
> > wrote:
> > >> >
> > >> >
> > >> > On 20.09.16 08:25, Thomas Abraham wrote:
> > >> >> On Tue, Sep 20, 2016 at 11:35 AM, Alexander Graf <agraf at suse.de>
> > >> wrote:
> > >> >>>
> > >> >>>
> > >> >>> Am 20.09.2016 um 07:51 schrieb Thomas Abraham
> > <ta.omasab at gmail.com>:
> > >> >>>
> > >> >>> Hi Alison,
> > >> >>>
> > >> >>>
> > >> >>> On Mon, Sep 19, 2016 at 7:38 PM, Alexander Graf <agraf at suse.de>
> > >> wrote:
> > >> >>>
> > >> >>>
> > >> >>>
> > >> >>> On 09.09.16 10:48, Alison Wang wrote:
> > >> >>>
> > >> >>> This patch is to use the the generic lowlevel_init instead of
> > the
> > >> >>>
> > >> >>> specific one.
> > >> >>>
> > >> >>>
> > >> >>> Signed-off-by: Alison Wang <alison.wang at nxp.com>
> > >> >>>
> > >> >>>
> > >> >>> If I had to guess, I'd think they only had their own version
> > >> because the
> > >> >>>
> > >> >>> old one required a GIC.
> > >> >>>
> > >> >>>
> > >> >>> I apologize for the delay.
> > >> >>>
> > >> >>> The reason for using a custom version was to avoid enabling
> > >> >>> ARMV8_MULTIENTRY config option since the Exynos7 code was
> ready
> > for
> > >> >>> it.
> > >> >>>
> > >> >>>
> > >> >>> Either way, since Samsung doesn't reply, I'm fine potentially
> > >> breaking
> > >> >>>
> > >> >>> their boards if that means that we can make progress for
> > actively
> > >> >>>
> > >> >>> maintained ones:
> > >> >>>
> > >> >>>
> > >> >>> Reviewed-by: Alexander Graf <agraf at suse.de>
> > >> >>>
> > >> >>>
> > >> >>> This patch without the ARMV8_MULTIENTRY and
> ARMV8_SWITCH_TO_EL1
> > >> config
> > >> >>> options does not switch the boot CPU from EL3 to EL1. So it
> > would
> > >> be
> > >> >>> preferable to not merge this patch until ARMV8_MULTIENTRY is
> > >> enabled
> > >> >>> for Exynos7.
> > >> >>>
> > >> >>>
> > >> >>> Why do you want to switch it to EL1 in the first place? Linux
> > >> >>> is
> > >> very happy
> > >> >>> to live in EL2 - which is what we call it in by default.
> > >> >>
> > >> >> Okay, there is no particular requirement to be in EL1 for
> Exynos7.
> > >> EL2
> > >> >> would also be fine. But Exynos7 support in u-boot is not yet
> > ready
> > >> for
> > >> >> enabling ARMV8_MULTIENTRY config option. Is there anything be
> > >> blocked
> > >> >> due to Exynos7 using a custom lowlevel_init function?
> > >> >
> > >> > Yes, we're changing the semantics of armv8_switch_to_el2 and
> > >> > armv8_switch_to_el1:
> > >> >
> > >> >
> > >> > http://lists.denx.de/pipermail/u-boot/2016-September/266217.html
> > >> >
> > >> > which is a prerequisite for AArch32 kernel boot on AArch64
> systems.
> > >>
> > >> Okay.
> > >>
> > >> >
> > >> > How quickly do you think you could make Exynos7 work with
> > MULTIENTRY?
> > >> >
> > >>
> > >> Exynos7420 uses CPU 0 of Cluster 1 as boot CPU (master CPU). The
> > macro
> > >> 'branch_if_master' requires all affinity values to be zero for a
> > >> CPU to be identified as a master CPU. And so the boot CPU is
> > >> incorrectly detected as a slave CPU. I have tested with the
> > >> following temporary workaround to enable ARMV8_MULTIENTRY on
> > >> Exynos7420. If it looks
> > fine,
> > >> this can be merged along with Alison's patch.
> > >>
> > >> Thomas.
> > >>
> > >> diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-
> > >> exynos/Kconfig index ce2a16f..45c5eeb 100644
> > >> --- a/arch/arm/mach-exynos/Kconfig
> > >> +++ b/arch/arm/mach-exynos/Kconfig
> > >> @@ -126,6 +126,8 @@ choice
> > >> config TARGET_ESPRESSO7420
> > >> bool "ESPRESSO7420 board"
> > >> select ARM64
> > >> + select ARMV8_MULTIENTRY
> > >> + select ARMV8_SWITCH_TO_EL1
> > >> select SUPPORT_SPL
> > >> select OF_CONTROL
> > >> select SPL_DISABLE_OF_CONTROL diff --git
> > >> a/arch/arm/mach-exynos/soc.c b/arch/arm/mach-exynos/soc.c index
> > >> f9c7468..6c3ebb0 100644
> > >> --- a/arch/arm/mach-exynos/soc.c
> > >> +++ b/arch/arm/mach-exynos/soc.c
> > >> @@ -9,6 +9,16 @@
> > >> #include <asm/io.h>
> > >> #include <asm/system.h>
> > >>
> > >> +#ifdef CONFIG_TARGET_ESPRESSO7420
> > >> +/*
> > >> + * Exynos7420 uses CPU0 of Cluster-1 as boot CPU. Due to this
> > >> branch_if_master
> > >> + * fails to identify as the master CPU. As temporary workaround,
> > setup
> > >> the
> > >> + * slave CPU boot address as "_main".
> > >> + */
> > >> +extern void _main(void);
> > >> +void *secondary_boot_addr = (void *)_main; #endif /*
> > >> +CONFIG_TARGET_ESPRESSO7420 */
> > >> +
> > >> void reset_cpu(ulong addr)
> > >> {
> > >> #ifdef CONFIG_CPU_V7
> > >> diff --git a/include/configs/exynos7420-common.h
> > >> b/include/configs/exynos7420-common.h
> > >> index 9e03962..6f58aef 100644
> > >> --- a/include/configs/exynos7420-common.h
> > >> +++ b/include/configs/exynos7420-common.h
> > >> @@ -48,6 +48,7 @@
> > >> #define CONFIG_IRAM_BASE 0x02100000
> > >> #define CONFIG_IRAM_SIZE 0x58000
> > >> #define CONFIG_IRAM_END (CONFIG_IRAM_BASE
> +
> > >> CONFIG_IRAM_SIZE)
> > >> +#define CPU_RELEASE_ADDR secondary_boot_addr
> > >>
> > >> /* Number of CPUs available */
> > >> #define CONFIG_CORE_COUNT 0x8
> > >>
> > >> >
> > >> > Alex
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