hi Linus:
> While the Freescale ARMv8 board LS2085A will enter U-Boot both
> on a master and a secondary (slave) CPU, this is not the common
> behaviour on ARMv8 platforms. The norm is that U-Boot is entered
> from the master CPU only, while the other CPUs are kept in
> WFI (wait for interrupt) state.
According to fsl-lsch3 source code,
Freescale LS2085A master cpu enter u-boot first, then it kick slaves up.
That's right?
There's ATF in Juno, so all slaves are held up.
>
> The code determining which CPU we are running on is using the
> MPIDR register, but the definition of that register varies with
> platform to some extent, and handling multi-cluster platforms
> (such as the Juno) will become cumbersome. It is better to only
> enable the multiple entry code on machines that actually need
> it and disable it by default.
>
> Make the single entry default and add a special
> ARMV8_MULTIENTRY KConfig option to be used by the
> platforms that need multientry and set it for the LS2085A.
> Delete all use of the CPU_RELEASE_ADDR from the Vexpress64
> boards as it is just totally unused and misleading, and
> make it conditional in the generic start.S code.
It's better to retain CPU_RELEASE_ADDR usage with CONFIG_ARMV8_MULTIENTRY.
It still useful when ATF or other PSCI service do not exist.
>
> This makes the Juno platform start U-Boot properly.
>
> Signed-off-by: Linus Walleij <linus.wall...@linaro.org>
> ---
> ChangeLog v1->v2:
> - Move configuration of ARMV8_MULTIENTRY over to Kconfig
> as requested by Tom Rini.
>
> This patch applied on top of the other patch series send,
> ending with
> [PATCH 4/4] vexpress64: support the Juno Development Platform
> Please apply it on top of these if the patch seems OK.
> ---
> arch/arm/Kconfig | 4 ++++
> arch/arm/cpu/armv8/Kconfig | 6 ++++++
> arch/arm/cpu/armv8/start.S | 8 ++++----
> arch/arm/include/asm/macro.h | 8 ++++++++
> board/armltd/vexpress64/vexpress64.c | 6 ------
> include/configs/vexpress_aemv8a.h | 8 --------
> 6 files changed, 22 insertions(+), 18 deletions(-)
> create mode 100644 arch/arm/cpu/armv8/Kconfig
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 986b4c5d81db..75dd9bb60d6b 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -743,10 +743,12 @@ config TARGET_VEXPRESS64_JUNO
> config TARGET_LS2085A_EMU
> bool "Support ls2085a_emu"
> select ARM64
> + select ARMV8_MULTIENTRY
>
> config TARGET_LS2085A_SIMU
> bool "Support ls2085a_simu"
> select ARM64
> + select ARMV8_MULTIENTRY
>
> config TARGET_LS1021AQDS
> bool "Support ls1021aqds"
> @@ -855,6 +857,8 @@ source "arch/arm/cpu/armv7/zynq/Kconfig"
>
> source "arch/arm/cpu/armv7/Kconfig"
>
> +source "arch/arm/cpu/armv8/Kconfig"
> +
> source "board/aristainetos/Kconfig"
> source "board/BuR/kwb/Kconfig"
> source "board/BuR/tseries/Kconfig"
> diff --git a/arch/arm/cpu/armv8/Kconfig b/arch/arm/cpu/armv8/Kconfig
> new file mode 100644
> index 000000000000..4cd84b031114
> --- /dev/null
> +++ b/arch/arm/cpu/armv8/Kconfig
> @@ -0,0 +1,6 @@
> +if ARM64
> +
> +config ARMV8_MULTIENTRY
> + boolean "Enable multiple CPUs to enter into U-boot"
> +
> +endif
> diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S
> index 4b11aa4f2227..9b439f30b779 100644
> --- a/arch/arm/cpu/armv8/start.S
> +++ b/arch/arm/cpu/armv8/start.S
> @@ -77,6 +77,7 @@ reset:
> /* Processor specific initialization */
> bl lowlevel_init
>
> +#ifdef CONFIG_ARMV8_MULTIENTRY
> branch_if_master x0, x1, master_cpu
>
> /*
> @@ -88,11 +89,10 @@ slave_cpu:
> ldr x0, [x1]
> cbz x0, slave_cpu
> br x0 /* branch to the given address */
> -
> - /*
> - * Master CPU
> - */
> master_cpu:
> + /* On the master CPU */
> +#endif /* CONFIG_ARMV8_MULTIENTRY */
> +
> bl _main
>
> /*-----------------------------------------------------------------------*/
> diff --git a/arch/arm/include/asm/macro.h b/arch/arm/include/asm/macro.h
> index 1c8c4251ee0c..3b3146ab2239 100644
> --- a/arch/arm/include/asm/macro.h
> +++ b/arch/arm/include/asm/macro.h
> @@ -78,6 +78,8 @@ lr .req x30
> * choose processor with all zero affinity value as the master.
> */
> .macro branch_if_slave, xreg, slave_label
> +#ifdef CONFIG_ARMV8_MULTIENTRY
> + /* NOTE: MPIDR handling will be erroneous on multi-cluster machines */
> mrs \xreg, mpidr_el1
> tst \xreg, #0xff /* Test Affinity 0 */
> b.ne \slave_label
> @@ -90,6 +92,7 @@ lr .req x30
> lsr \xreg, \xreg, #16
> tst \xreg, #0xff /* Test Affinity 3 */
> b.ne \slave_label
> +#endif
> .endm
>
> /*
> @@ -97,12 +100,17 @@ lr .req x30
> * choose processor with all zero affinity value as the master.
> */
> .macro branch_if_master, xreg1, xreg2, master_label
> +#ifdef CONFIG_ARMV8_MULTIENTRY
> + /* NOTE: MPIDR handling will be erroneous on multi-cluster machines */
> mrs \xreg1, mpidr_el1
> lsr \xreg2, \xreg1, #32
> lsl \xreg1, \xreg1, #40
> lsr \xreg1, \xreg1, #40
> orr \xreg1, \xreg1, \xreg2
> cbz \xreg1, \master_label
> +#else
> + b \master_label
> +#endif
> .endm
>
> .macro armv8_switch_to_el2_m, xreg1
> diff --git a/board/armltd/vexpress64/vexpress64.c
> b/board/armltd/vexpress64/vexpress64.c
> index 58973185ecda..7ab000cca77b 100644
> --- a/board/armltd/vexpress64/vexpress64.c
> +++ b/board/armltd/vexpress64/vexpress64.c
> @@ -22,12 +22,6 @@ int board_init(void)
>
> int dram_init(void)
> {
> - /*
> - * Clear spin table so that secondary processors
> - * observe the correct value after waken up from wfe.
> - */
> - *(unsigned long *)CPU_RELEASE_ADDR = 0;
> -
> gd->ram_size = PHYS_SDRAM_1_SIZE;
> return 0;
> }
> diff --git a/include/configs/vexpress_aemv8a.h
> b/include/configs/vexpress_aemv8a.h
> index 7fb28a54ba17..e276fff7e442 100644
> --- a/include/configs/vexpress_aemv8a.h
> +++ b/include/configs/vexpress_aemv8a.h
> @@ -56,14 +56,6 @@
> /* Flat Device Tree Definitions */
> #define CONFIG_OF_LIBFDT
>
> -
> -/* SMP Spin Table Definitions */
> -#ifdef CONFIG_TARGET_VEXPRESS64_BASE_FVP
> -#define CPU_RELEASE_ADDR (CONFIG_SYS_SDRAM_BASE + 0x03f00000)
> -#else
> -#define CPU_RELEASE_ADDR (CONFIG_SYS_SDRAM_BASE + 0x7fff0)
> -#endif
> -
> /* CS register bases for the original memory map. */
> #define V2M_PA_CS0 0x00000000
> #define V2M_PA_CS1 0x14000000
> --
> 1.9.3
>
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