[PATCH 2/2] ARM: sun6i: Add SMP support for the Allwinner A31

From: Maxime Ripard
Date: Sun Nov 03 2013 - 04:35:55 EST

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@xxxxxxxxxxxxxxxxxx>
---
arch/arm/mach-sunxi/Makefile | 1 +
arch/arm/mach-sunxi/common.h | 19 +++++++
arch/arm/mach-sunxi/headsmp.S | 11 ++++
arch/arm/mach-sunxi/platsmp.c | 115 ++++++++++++++++++++++++++++++++++++++++++
arch/arm/mach-sunxi/sunxi.c | 3 ++
5 files changed, 149 insertions(+)
create mode 100644 arch/arm/mach-sunxi/common.h
create mode 100644 arch/arm/mach-sunxi/headsmp.S
create mode 100644 arch/arm/mach-sunxi/platsmp.c

diff --git a/arch/arm/mach-sunxi/Makefile b/arch/arm/mach-sunxi/Makefile
index 93bebfc3ff9f..d9397202d6ec 100644
--- a/arch/arm/mach-sunxi/Makefile
+++ b/arch/arm/mach-sunxi/Makefile
@@ -1 +1,2 @@
obj-$(CONFIG_ARCH_SUNXI) += sunxi.o
+obj-$(CONFIG_SMP) += platsmp.o headsmp.o
diff --git a/arch/arm/mach-sunxi/common.h b/arch/arm/mach-sunxi/common.h
new file mode 100644
index 000000000000..9e5ac4756cbb
--- /dev/null
+++ b/arch/arm/mach-sunxi/common.h
@@ -0,0 +1,19 @@
+/*
+ * Core functions for Allwinner SoCs
+ *
+ * Copyright (C) 2013 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
+ *
+ * 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.
+ */
+
+#ifndef __ARCH_SUNXI_COMMON_H_
+#define __ARCH_SUNXI_COMMON_H_
+
+void sun6i_secondary_startup(void);
+extern struct smp_operations sun6i_smp_ops;
+
+#endif /* __ARCH_SUNXI_COMMON_H_ */
diff --git a/arch/arm/mach-sunxi/headsmp.S b/arch/arm/mach-sunxi/headsmp.S
new file mode 100644
index 000000000000..f5ff05e0e6a3
--- /dev/null
+++ b/arch/arm/mach-sunxi/headsmp.S
@@ -0,0 +1,11 @@
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+ .section ".text.head", "ax"
+ __CPUINIT
+
+ENTRY(sun6i_secondary_startup)
+ msr cpsr_fsxc, #0xd3
+ b secondary_startup
+ENDPROC(sun6i_secondary_startup)
+
diff --git a/arch/arm/mach-sunxi/platsmp.c b/arch/arm/mach-sunxi/platsmp.c
new file mode 100644
index 000000000000..90045700c429
--- /dev/null
+++ b/arch/arm/mach-sunxi/platsmp.c
@@ -0,0 +1,115 @@
+/*
+ * SMP support for Allwinner SoCs
+ *
+ * Copyright (C) 2013 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
+ *
+ * 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)
+ panic("Missing A31 PRCM node in the device tree\n");
+
+ prcm_membase = of_iomap(node, 0);
+ if (!prcm_membase)
+ panic("Couldn't map A31 PRCM registers\n");
+
+ node = of_find_compatible_node(NULL, NULL,
+ "allwinner,sun6i-a31-cpuconfig");
+ if (!node)
+ panic("Missing A31 CPU config node in the device tree\n");
+
+ cpucfg_membase = of_iomap(node, 0);
+ if (!cpucfg_membase)
+ panic("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;
+
+ 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,
+};
diff --git a/arch/arm/mach-sunxi/sunxi.c b/arch/arm/mach-sunxi/sunxi.c
index f184f6c2fa33..b2e570253a8f 100644
--- a/arch/arm/mach-sunxi/sunxi.c
+++ b/arch/arm/mach-sunxi/sunxi.c
@@ -26,6 +26,8 @@
#include <asm/mach/map.h>
#include <asm/system_misc.h>

+#include "common.h"
+
#define SUN4I_WATCHDOG_CTRL_REG 0x00
#define SUN4I_WATCHDOG_CTRL_RESTART BIT(0)
#define SUN4I_WATCHDOG_MODE_REG 0x04
@@ -147,6 +149,7 @@ DT_MACHINE_START(SUN6I_DT, "Allwinner sun6i (A31) Family")
.init_time = sunxi_timer_init,
.dt_compat = sun6i_board_dt_compat,
.restart = sun6i_restart,
+ .smp = smp_ops(sun6i_smp_ops),
MACHINE_END

static const char * const sun7i_board_dt_compat[] = {
--
1.8.4

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