[U-Boot] [RFC PATCH 7/8] sunxi: Add basic PSCI implementation for multi-cluster SoCs

[Maxime Ripard <maxime.ripard@free-electrons.com>]

Hi,

On Wed, Jun 07, 2017 at 08:47:20AM +0800, Icenowy Zheng wrote:
> From: Chen-Yu Tsai <wens@csie.org>
> 
> Allwinner A80 and A83T SoCs have two clusters of CPU, each cluster
> contains 4 cores. A80 is Cortex-A15 + Cortex-A7 configuration, while
> A83T has two clusters of Cortex-A7.
> 
> This patch adds a basic version that allows bringing up the four cores
> in the first cluster. The structure is based on existing sunxi PSCI code.
> 
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> [Icenowy: adapt for A83T]
> Signed-off-by: Icenowy Zheng <icenowy@aosc.io>

Ideally, Marc should be in Cc in order to review this.

> ---
>  arch/arm/cpu/armv7/sunxi/Makefile    |   4 +
>  arch/arm/cpu/armv7/sunxi/psci-mcpm.c | 258 +++++++++++++++++++++++++++++++++++
>  2 files changed, 262 insertions(+)
>  create mode 100644 arch/arm/cpu/armv7/sunxi/psci-mcpm.c
> 
> diff --git a/arch/arm/cpu/armv7/sunxi/Makefile b/arch/arm/cpu/armv7/sunxi/Makefile
> index 8c026ff052..c789f686fd 100644
> --- a/arch/arm/cpu/armv7/sunxi/Makefile
> +++ b/arch/arm/cpu/armv7/sunxi/Makefile
> @@ -14,8 +14,12 @@ obj-$(CONFIG_MACH_SUN8I_H3)	+= tzpc.o
>  obj-$(CONFIG_MACH_SUN8I_A83T)	+= tzpc.o
>  
>  ifndef CONFIG_SPL_BUILD
> +ifdef CONFIG_MACH_SUN8I_A83T
> +obj-$(CONFIG_ARMV7_PSCI)	+= psci-mcpm.o
> +else
>  obj-$(CONFIG_ARMV7_PSCI)	+= psci.o
>  endif
> +endif
>  
>  ifdef CONFIG_SPL_BUILD
>  obj-y	+= fel_utils.o
> diff --git a/arch/arm/cpu/armv7/sunxi/psci-mcpm.c b/arch/arm/cpu/armv7/sunxi/psci-mcpm.c
> new file mode 100644
> index 0000000000..ba8d669c7e
> --- /dev/null
> +++ b/arch/arm/cpu/armv7/sunxi/psci-mcpm.c
> @@ -0,0 +1,258 @@
> +/*
> + * Copyright (C) 2016
> + * Author: Chen-Yu Tsai <wens@csie.org>
> + *
> + * Based on assembly code by Marc Zyngier <marc.zyngier@arm.com>,
> + * which was based on code by Carl van Schaik <carl@ok-labs.com>.
> + *
> + * SPDX-License-Identifier:	GPL-2.0
> + */
> +#include <config.h>
> +#include <common.h>
> +
> +#include <asm/arch/cpu.h>
> +#include <asm/arch/cpucfg.h>
> +#include <asm/arch/prcm.h>
> +#include <asm/armv7.h>
> +#include <asm/io.h>
> +#include <asm/psci.h>
> +#include <asm/secure.h>
> +
> +#include <linux/bitops.h>
> +
> +/*
> + * NOTE dense CPU IDs (0~3 for first cluster of 4 cores, 4~7 for the
> + * second cluster) are used throughout the PSCI code. Any MPIDR style
> + * values must be converted.
> + */
> +
> +/*
> + * Provide a dense CPU ID for 2-cluster systems. This must be coded in
> + * assembly as it gets called from psci_stack_setup, when the stack isn't
> + * available yet.
> + *
> + * Only r0 and r3 is usable. r8 - r12 are available if this function is
> + * only called from psci_stack_setup, which we cannot guarantee.
> + */
> +u32 __secure __naked psci_get_cpu_id(void)
> +{
> +	asm volatile (
> +		"mrc	p15, 0, r3, c0, c0, 5	@ Get MPIDR\n"
> +		"lsr	r0, r3, #6\n"
> +		"and	r3, r3, #3\n"
> +		"and	r0, r0, #4\n"
> +		"orr	r0, r0, r3\n"
> +		"bx	lr\n"
> +	);
> +
> +	/*
> +	 * The last five lines are the compiler generated assembly code for
> +	 *
> +	 *	return (reg & 0x3) | (((reg >> 8) & 0x1) << 2);
> +	 *
> +	 * We can't guarantee that all compilers correctly use only r0 and
> +	 * r3, so we use inline assembly here.
> +	 */
> +}
> +
> +static void __secure cp15_write_cntp_tval(u32 tval)
> +{
> +	asm volatile ("mcr p15, 0, %0, c14, c2, 0" : : "r" (tval));
> +}
> +
> +static void __secure cp15_write_cntp_ctl(u32 val)
> +{
> +	asm volatile ("mcr p15, 0, %0, c14, c2, 1" : : "r" (val));
> +}
> +
> +static u32 __secure cp15_read_cntp_ctl(void)
> +{
> +	u32 val;
> +
> +	asm volatile ("mrc p15, 0, %0, c14, c2, 1" : "=r" (val));
> +
> +	return val;
> +}
> +
> +#define ONE_US (COUNTER_FREQUENCY / 1000000)
> +
> +/* Use a different name to avoid clashing with the non-secure function */
> +static void __secure __udelay_sec(unsigned long us)
> +{
> +	u32 reg = ONE_US * us;
> +
> +	cp15_write_cntp_tval(reg);
> +	isb();
> +	cp15_write_cntp_ctl(3);
> +
> +	do {
> +		isb();
> +		reg = cp15_read_cntp_ctl();
> +	} while (!(reg & BIT(2)));
> +
> +	cp15_write_cntp_ctl(0);
> +	isb();
> +}
> +
> +static void __secure clamp_release(u32 *clamp)
> +{
> +	writel(0xff, clamp);
> +	__udelay_sec(10);
> +	writel(0xfe, clamp);
> +	__udelay_sec(10);
> +	writel(0xf8, clamp);
> +	__udelay_sec(10);
> +	writel(0xf0, clamp);
> +	__udelay_sec(10);
> +	writel(0x00, clamp);
> +}
> +
> +static void __secure clamp_set(u32 *clamp)
> +{
> +	writel(0xff, clamp);
> +}
> +
> +static void __secure sunxi_core_power_switch(u32 *clamp, u32 *pwroff,
> +					     bool on, int cpu)
> +{
> +	if (on) {
> +		/* Release power clamp */
> +		clamp_release(clamp);
> +
> +		__udelay_sec(20);
> +
> +		/* Clear power gating */
> +		clrbits_le32(pwroff, BIT(cpu));
> +	} else {
> +		/* Set power gating */
> +		setbits_le32(pwroff, BIT(cpu));
> +
> +		__udelay_sec(20);
> +
> +		/* Activate power clamp */
> +		clamp_set(clamp);
> +	}
> +}
> +
> +static int __secure sunxi_cluster_is_a7(int cluster)
> +{
> +#ifdef CONFIG_MACH_SUN8I_A83T
> +	return 1;
> +#else
> +	return (clustter == 0);

This doesn't compile.


Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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