[U-Boot] [PATCH 08/10] sunxi: Add basic PSCI implementation for A80

[Hans de Goede]

Hi,

On 09-11-16 11:21, Chen-Yu Tsai wrote:
> The A80 is a big.LITTLE multi-cluster SoC, with a different layout for
> the PRCM and CPUCFG registers. As such it needs a different PSCI
> implementation.
>
> 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 at csie.org>

LGTM:

Reviewed-by: Hans de Goede <hdegoede at redhat.com>

Regards,

Hans


> ---
>  arch/arm/cpu/armv7/sunxi/Makefile    |   4 +
>  arch/arm/cpu/armv7/sunxi/psci-mcpm.c | 234 +++++++++++++++++++++++++++++++++++
>  2 files changed, 238 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 239c659ec032..b18e5f1fa974 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_SUN9I)	+= tzpc.o
>
>  ifndef CONFIG_SPL_BUILD
> +ifdef CONFIG_MACH_SUN9I
> +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 000000000000..3ede07cace2c
> --- /dev/null
> +++ b/arch/arm/cpu/armv7/sunxi/psci-mcpm.c
> @@ -0,0 +1,234 @@
> +/*
> + * Copyright (C) 2016
> + * Author: Chen-Yu Tsai <wens at csie.org>
> + *
> + * Based on assembly code by Marc Zyngier <marc.zyngier at arm.com>,
> + * which was based on code by Carl van Schaik <carl at ok-labs.com>.
> + *
> + * SPDX-License-Identifier:	GPL-2.0
> + */
> +#include <config.h>
> +#include <common.h>
> +
> +#include <asm/arch/cpu.h>
> +#include <asm/arch/cpucfg_sun9i.h>
> +#include <asm/arch/prcm_sun9i.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 (CONFIG_TIMER_CLK_FREQ / 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 void __secure sunxi_cpu_set_power(int cpu, bool on)
> +{
> +	struct sunxi_prcm_reg *prcm =
> +		(struct sunxi_prcm_reg *)SUNXI_PRCM_BASE;
> +	int cluster = (cpu >> 2) & 0x1;
> +	int core = cpu & 0x3;
> +
> +	sunxi_core_power_switch(&prcm->cpu_pwr_clamp[cluster][core],
> +				&prcm->cpu_pwroff[cluster], on, core);
> +}
> +
> +static u32 __secure cp15_read_scr(void)
> +{
> +	u32 scr;
> +
> +	asm volatile ("mrc p15, 0, %0, c1, c1, 0" : "=r" (scr));
> +
> +	return scr;
> +}
> +
> +static void __secure cp15_write_scr(u32 scr)
> +{
> +	asm volatile ("mcr p15, 0, %0, c1, c1, 0" : : "r" (scr));
> +	isb();
> +}
> +
> +int __secure psci_cpu_on(u32 __always_unused unused, u32 mpidr, u32 pc)
> +{
> +	struct sunxi_cpucfg_reg *cpucfg =
> +		(struct sunxi_cpucfg_reg *)SUNXI_CPUCFG_BASE;
> +	struct sunxi_prcm_reg *prcm =
> +		(struct sunxi_prcm_reg *)SUNXI_PRCM_BASE;
> +	u32 cluster = (mpidr >> 8) & 0x1;
> +	u32 cpu = mpidr & 0x3;
> +	u32 cpuid = cpu | (cluster << 2);
> +
> +	/* TODO We don't support multi-cluster yet */
> +	if (cluster > 0)
> +		return ARM_PSCI_RET_INVAL;
> +
> +	/* store target PC */
> +	psci_save_target_pc(cpuid, pc);
> +
> +	/* Set secondary core power on PC */
> +	writel((u32)&psci_cpu_entry, &prcm->cpu_soft_entry);
> +
> +	/* Assert power-on reset on target CPU */
> +	clrbits_le32(&prcm->cpu_rst[cluster], BIT(cpu));
> +
> +	/* Cortex-A7: hold L1 cache reset disable signal low */
> +	if (cluster == 0)
> +		clrbits_le32(&cpucfg->cluster[cluster].ctrl0,
> +			     CPUCFG_CX_CTRL0_L1_RST_DISABLE(cpu));
> +
> +	/* Lock CPU (Disable external debug access) */
> +	clrbits_le32(&cpucfg->cluster_reset[cluster],
> +		     CPUCFG_CX_RST_DBG(cpu));
> +
> +	/* Cortex-A7: Assert ETM reset */
> +	if (cluster == 0)
> +		clrbits_le32(&cpucfg->cluster_reset[cluster],
> +			     CPUCFG_CX_RST_ETM(cpu));
> +
> +	/*
> +	 * Allwinner code also asserts resets for NEON on A15. According
> +	 * to ARM manuals, asserting power-on reset is sufficient.
> +	 */
> +
> +	/* Power up target CPU */
> +	sunxi_cpu_set_power(cpu, true);
> +
> +	/* De-assert power-on reset on target CPU */
> +	setbits_le32(&prcm->cpu_rst[cluster], BIT(cpu));
> +
> +	/* De-assert core reset on target CPU */
> +	setbits_le32(&cpucfg->cluster_reset[cluster],
> +		     CPUCFG_CX_RST_CORE(cpu));
> +
> +	/* Cortex-A7: De-assert ETM reset */
> +	if (cluster == 0)
> +		setbits_le32(&cpucfg->cluster_reset[cluster],
> +			     CPUCFG_CX_RST_ETM(cpu));
> +
> +	/* Unlock CPU (Disable external debug access) */
> +	setbits_le32(&cpucfg->cluster_reset[cluster],
> +		     CPUCFG_CX_RST_DBG(cpu));
> +
> +	return ARM_PSCI_RET_SUCCESS;
> +}
> +
> +void __secure psci_arch_init(void)
> +{
> +	u32 reg;
> +
> +	reg = cp15_read_scr();
> +	reg &= ~BIT(0); /* Secure mode */
> +	cp15_write_scr(reg);
> +}
>