platsmp.c
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/*
* SMP support for Allwinner SoCs
*
* Copyright (C) 2013 Maxime Ripard
*
* Maxime Ripard <maxime.ripard@free-electrons.com>
*
* Based on code
* Copyright (C) 2012-2013 Allwinner Ltd.
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/memory.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/smp.h>
#include "common.h"
#define CPUCFG_CPU_PWR_CLAMP_STATUS_REG(cpu) ((cpu) * 0x40 + 0x64)
#define CPUCFG_CPU_RST_CTRL_REG(cpu) (((cpu) + 1) * 0x40)
#define CPUCFG_CPU_CTRL_REG(cpu) (((cpu) + 1) * 0x40 + 0x04)
#define CPUCFG_CPU_STATUS_REG(cpu) (((cpu) + 1) * 0x40 + 0x08)
#define CPUCFG_GEN_CTRL_REG 0x184
#define CPUCFG_PRIVATE0_REG 0x1a4
#define CPUCFG_PRIVATE1_REG 0x1a8
#define CPUCFG_DBG_CTL0_REG 0x1e0
#define CPUCFG_DBG_CTL1_REG 0x1e4
#define PRCM_CPU_PWROFF_REG 0x100
#define PRCM_CPU_PWR_CLAMP_REG(cpu) (((cpu) * 4) + 0x140)
static void __iomem *cpucfg_membase;
static void __iomem *prcm_membase;
static DEFINE_SPINLOCK(cpu_lock);
static void __init sun6i_smp_prepare_cpus(unsigned int max_cpus)
{
struct device_node *node;
node = of_find_compatible_node(NULL, NULL, "allwinner,sun6i-a31-prcm");
if (!node) {
pr_err("Missing A31 PRCM node in the device tree\n");
return;
}
prcm_membase = of_iomap(node, 0);
if (!prcm_membase) {
pr_err("Couldn't map A31 PRCM registers\n");
return;
}
node = of_find_compatible_node(NULL, NULL,
"allwinner,sun6i-a31-cpuconfig");
if (!node) {
pr_err("Missing A31 CPU config node in the device tree\n");
return;
}
cpucfg_membase = of_iomap(node, 0);
if (!cpucfg_membase)
pr_err("Couldn't map A31 CPU config registers\n");
}
static int sun6i_smp_boot_secondary(unsigned int cpu,
struct task_struct *idle)
{
u32 reg;
int i;
if (!(prcm_membase && cpucfg_membase))
return -EFAULT;
spin_lock(&cpu_lock);
/* Set CPU boot address */
writel(virt_to_phys(sun6i_secondary_startup),
cpucfg_membase + CPUCFG_PRIVATE0_REG);
/* Assert the CPU core in reset */
writel(0, cpucfg_membase + CPUCFG_CPU_RST_CTRL_REG(cpu));
/* Assert the L1 cache in reset */
reg = readl(cpucfg_membase + CPUCFG_GEN_CTRL_REG);
writel(reg & ~BIT(cpu), cpucfg_membase + CPUCFG_GEN_CTRL_REG);
/* Disable external debug access */
reg = readl(cpucfg_membase + CPUCFG_DBG_CTL1_REG);
writel(reg & ~BIT(cpu), cpucfg_membase + CPUCFG_DBG_CTL1_REG);
/* Power up the CPU */
for (i = 0; i <= 8; i++)
writel(0xff >> i, prcm_membase + PRCM_CPU_PWR_CLAMP_REG(cpu));
mdelay(10);
/* Clear CPU power-off gating */
reg = readl(prcm_membase + PRCM_CPU_PWROFF_REG);
writel(reg & ~BIT(cpu), prcm_membase + PRCM_CPU_PWROFF_REG);
mdelay(1);
/* Deassert the CPU core reset */
writel(3, cpucfg_membase + CPUCFG_CPU_RST_CTRL_REG(cpu));
/* Enable back the external debug accesses */
reg = readl(cpucfg_membase + CPUCFG_DBG_CTL1_REG);
writel(reg | BIT(cpu), cpucfg_membase + CPUCFG_DBG_CTL1_REG);
spin_unlock(&cpu_lock);
return 0;
}
struct smp_operations sun6i_smp_ops __initdata = {
.smp_prepare_cpus = sun6i_smp_prepare_cpus,
.smp_boot_secondary = sun6i_smp_boot_secondary,
};