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author | Maxime Ripard <maxime.ripard@free-electrons.com> | 2013-11-03 10:30:13 +0100 |
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committer | Maxime Ripard <maxime.ripard@free-electrons.com> | 2013-12-16 21:33:41 +0100 |
commit | 73346794b48237b7b4c2a5c02b12e3c4f1da7551 (patch) | |
tree | 49e6ef08466d94f7899e4beea8bb4cc7991b3f75 /arch/arm/mach-sunxi/platsmp.c | |
parent | a3b7a0c84d56bc50d33428f302778104b7164ba2 (diff) | |
download | linux-73346794b48237b7b4c2a5c02b12e3c4f1da7551.tar.bz2 |
ARM: sun6i: Add SMP support for the Allwinner A31
The A31 is a quad Cortex-A7. Add the logic to use the IPs used to
control the CPU configuration and the CPU power so that we can bring up
secondary CPUs at boot.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Diffstat (limited to 'arch/arm/mach-sunxi/platsmp.c')
-rw-r--r-- | arch/arm/mach-sunxi/platsmp.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/arch/arm/mach-sunxi/platsmp.c b/arch/arm/mach-sunxi/platsmp.c new file mode 100644 index 000000000000..7b141d8342a1 --- /dev/null +++ b/arch/arm/mach-sunxi/platsmp.c @@ -0,0 +1,124 @@ +/* + * 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, +}; |