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Subject[PATCH v2 1/5] ARM: sun9i: Support SMP on A80 with Multi-Cluster Power Management (MCPM)
Date
From: Chen-Yu Tsai <wens@csie.org>

The A80 is a big.LITTLE SoC with 1 cluster of 4 Cortex-A7s and
1 cluster of 4 Cortex-A15s.

This patch adds support to bring up the second cluster and thus all
cores using the common MCPM code. Core/cluster power down has not
been implemented, thus CPU hotplugging and big.LITTLE switcher is
not supported.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Mylène Josserand <mylene.josserand@free-electrons.com>
---
arch/arm/mach-sunxi/Kconfig | 10 ++
arch/arm/mach-sunxi/Makefile | 1 +
arch/arm/mach-sunxi/mcpm.c | 391 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 402 insertions(+)
create mode 100644 arch/arm/mach-sunxi/mcpm.c

diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig
index 58153cdf025b..177380548d99 100644
--- a/arch/arm/mach-sunxi/Kconfig
+++ b/arch/arm/mach-sunxi/Kconfig
@@ -47,5 +47,15 @@ config MACH_SUN9I
bool "Allwinner (sun9i) SoCs support"
default ARCH_SUNXI
select ARM_GIC
+ imply MCPM
+
+config SUN9I_A80_MCPM
+ bool "Allwinner A80 Multi-Cluster PM support"
+ depends on MCPM && MACH_SUN9I
+ default MACH_SUN9I
+ select ARM_CCI400_PORT_CTRL
+ help
+ This is needed to provide CPU and cluster power management
+ on Allwinner A80 implementing big.LITTLE.

endif
diff --git a/arch/arm/mach-sunxi/Makefile b/arch/arm/mach-sunxi/Makefile
index 27b168f121a1..e8558912c714 100644
--- a/arch/arm/mach-sunxi/Makefile
+++ b/arch/arm/mach-sunxi/Makefile
@@ -1,2 +1,3 @@
obj-$(CONFIG_ARCH_SUNXI) += sunxi.o
obj-$(CONFIG_SMP) += platsmp.o
+obj-$(CONFIG_SUN9I_A80_MCPM) += mcpm.o
diff --git a/arch/arm/mach-sunxi/mcpm.c b/arch/arm/mach-sunxi/mcpm.c
new file mode 100644
index 000000000000..4b6e1d6ae379
--- /dev/null
+++ b/arch/arm/mach-sunxi/mcpm.c
@@ -0,0 +1,391 @@
+/*
+ * Copyright (c) 2015 Chen-Yu Tsai
+ *
+ * Chen-Yu Tsai <wens@csie.org>
+ *
+ * arch/arm/mach-sunxi/mcpm.c
+ *
+ * Based on arch/arm/mach-exynos/mcpm-exynos.c and Allwinner code
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/arm-cci.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+
+#include <asm/cputype.h>
+#include <asm/cp15.h>
+#include <asm/mcpm.h>
+
+#define SUNXI_CPUS_PER_CLUSTER 4
+#define SUNXI_NR_CLUSTERS 2
+
+#define SUN9I_A80_A15_CLUSTER 1
+
+#define CPUCFG_CX_CTRL_REG0(c) (0x10 * (c))
+#define CPUCFG_CX_CTRL_REG0_L1_RST_DISABLE(n) BIT(n)
+#define CPUCFG_CX_CTRL_REG0_L1_RST_DISABLE_ALL 0xf
+#define CPUCFG_CX_CTRL_REG0_L2_RST_DISABLE_A7 BIT(4)
+#define CPUCFG_CX_CTRL_REG0_L2_RST_DISABLE_A15 BIT(0)
+#define CPUCFG_CX_CTRL_REG1(c) (0x10 * (c) + 0x4)
+#define CPUCFG_CX_CTRL_REG1_ACINACTM BIT(0)
+#define CPUCFG_CX_RST_CTRL(c) (0x80 + 0x4 * (c))
+#define CPUCFG_CX_RST_CTRL_DBG_SOC_RST BIT(24)
+#define CPUCFG_CX_RST_CTRL_ETM_RST(n) BIT(20 + (n))
+#define CPUCFG_CX_RST_CTRL_ETM_RST_ALL (0xf << 20)
+#define CPUCFG_CX_RST_CTRL_DBG_RST(n) BIT(16 + (n))
+#define CPUCFG_CX_RST_CTRL_DBG_RST_ALL (0xf << 16)
+#define CPUCFG_CX_RST_CTRL_H_RST BIT(12)
+#define CPUCFG_CX_RST_CTRL_L2_RST BIT(8)
+#define CPUCFG_CX_RST_CTRL_CX_RST(n) BIT(4 + (n))
+#define CPUCFG_CX_RST_CTRL_CORE_RST(n) BIT(n)
+
+#define PRCM_CPU_PO_RST_CTRL(c) (0x4 + 0x4 * (c))
+#define PRCM_CPU_PO_RST_CTRL_CORE(n) BIT(n)
+#define PRCM_CPU_PO_RST_CTRL_CORE_ALL 0xf
+#define PRCM_PWROFF_GATING_REG(c) (0x100 + 0x4 * (c))
+#define PRCM_PWROFF_GATING_REG_CLUSTER BIT(4)
+#define PRCM_PWROFF_GATING_REG_CORE(n) BIT(n)
+#define PRCM_PWR_SWITCH_REG(c, cpu) (0x140 + 0x10 * (c) + 0x4 * (cpu))
+#define PRCM_CPU_SOFT_ENTRY_REG 0x164
+
+static void __iomem *cpucfg_base;
+static void __iomem *prcm_base;
+
+static int sunxi_cpu_power_switch_set(unsigned int cpu, unsigned int cluster,
+ bool enable)
+{
+ u32 reg;
+
+ /* control sequence from Allwinner A80 user manual v1.2 PRCM section */
+ reg = readl(prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
+ if (enable) {
+ if (reg == 0x00) {
+ pr_debug("power clamp for cluster %u cpu %u already open\n",
+ cluster, cpu);
+ return 0;
+ }
+
+ writel(0xff, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
+ udelay(10);
+ writel(0xfe, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
+ udelay(10);
+ writel(0xf8, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
+ udelay(10);
+ writel(0xf0, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
+ udelay(10);
+ writel(0x00, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
+ udelay(10);
+ } else {
+ writel(0xff, prcm_base + PRCM_PWR_SWITCH_REG(cluster, cpu));
+ udelay(10);
+ }
+
+ return 0;
+}
+
+static int sunxi_cpu_powerup(unsigned int cpu, unsigned int cluster)
+{
+ u32 reg;
+
+ pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+ if (cpu >= SUNXI_CPUS_PER_CLUSTER || cluster >= SUNXI_NR_CLUSTERS)
+ return -EINVAL;
+
+ /* assert processor power-on reset */
+ reg = readl(prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
+ reg &= ~PRCM_CPU_PO_RST_CTRL_CORE(cpu);
+ writel(reg, prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
+
+ /* Cortex-A7: hold L1 reset disable signal low */
+ if (!(of_machine_is_compatible("allwinner,sun9i-a80") &&
+ cluster == SUN9I_A80_A15_CLUSTER)) {
+ reg = readl(cpucfg_base + CPUCFG_CX_CTRL_REG0(cluster));
+ reg &= ~CPUCFG_CX_CTRL_REG0_L1_RST_DISABLE(cpu);
+ writel(reg, cpucfg_base + CPUCFG_CX_CTRL_REG0(cluster));
+ }
+
+ /* assert processor related resets */
+ reg = readl(cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
+ reg &= ~CPUCFG_CX_RST_CTRL_DBG_RST(cpu);
+
+ /*
+ * Allwinner code also asserts resets for NEON on A15. According
+ * to ARM manuals, asserting power-on reset is sufficient.
+ */
+ if (!(of_machine_is_compatible("allwinner,sun9i-a80") &&
+ cluster == SUN9I_A80_A15_CLUSTER)) {
+ reg &= ~CPUCFG_CX_RST_CTRL_ETM_RST(cpu);
+ }
+ writel(reg, cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
+
+ /* open power switch */
+ sunxi_cpu_power_switch_set(cpu, cluster, true);
+
+ /* clear processor power gate */
+ reg = readl(prcm_base + PRCM_PWROFF_GATING_REG(cluster));
+ reg &= ~PRCM_PWROFF_GATING_REG_CORE(cpu);
+ writel(reg, prcm_base + PRCM_PWROFF_GATING_REG(cluster));
+ udelay(20);
+
+ /* de-assert processor power-on reset */
+ reg = readl(prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
+ reg |= PRCM_CPU_PO_RST_CTRL_CORE(cpu);
+ writel(reg, prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
+
+ /* de-assert all processor resets */
+ reg = readl(cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
+ reg |= CPUCFG_CX_RST_CTRL_DBG_RST(cpu);
+ reg |= CPUCFG_CX_RST_CTRL_CORE_RST(cpu);
+ if (!(of_machine_is_compatible("allwinner,sun9i-a80") &&
+ cluster == SUN9I_A80_A15_CLUSTER)) {
+ reg |= CPUCFG_CX_RST_CTRL_ETM_RST(cpu);
+ } else {
+ reg |= CPUCFG_CX_RST_CTRL_CX_RST(cpu); /* NEON */
+ }
+ writel(reg, cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
+
+ return 0;
+}
+
+static int sunxi_cluster_powerup(unsigned int cluster)
+{
+ u32 reg;
+
+ pr_debug("%s: cluster %u\n", __func__, cluster);
+ if (cluster >= SUNXI_NR_CLUSTERS)
+ return -EINVAL;
+
+ /* assert ACINACTM */
+ reg = readl(cpucfg_base + CPUCFG_CX_CTRL_REG1(cluster));
+ reg |= CPUCFG_CX_CTRL_REG1_ACINACTM;
+ writel(reg, cpucfg_base + CPUCFG_CX_CTRL_REG1(cluster));
+
+ /* assert cluster processor power-on resets */
+ reg = readl(prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
+ reg &= ~PRCM_CPU_PO_RST_CTRL_CORE_ALL;
+ writel(reg, prcm_base + PRCM_CPU_PO_RST_CTRL(cluster));
+
+ /* assert cluster resets */
+ reg = readl(cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
+ reg &= ~CPUCFG_CX_RST_CTRL_DBG_SOC_RST;
+ reg &= ~CPUCFG_CX_RST_CTRL_DBG_RST_ALL;
+ reg &= ~CPUCFG_CX_RST_CTRL_H_RST;
+ reg &= ~CPUCFG_CX_RST_CTRL_L2_RST;
+
+ /*
+ * Allwinner code also asserts resets for NEON on A15. According
+ * to ARM manuals, asserting power-on reset is sufficient.
+ */
+ if (!(of_machine_is_compatible("allwinner,sun9i-a80") &&
+ cluster == SUN9I_A80_A15_CLUSTER)) {
+ reg &= ~CPUCFG_CX_RST_CTRL_ETM_RST_ALL;
+ }
+ writel(reg, cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
+
+ /* hold L1/L2 reset disable signals low */
+ reg = readl(cpucfg_base + CPUCFG_CX_CTRL_REG0(cluster));
+ if (of_machine_is_compatible("allwinner,sun9i-a80") &&
+ cluster == SUN9I_A80_A15_CLUSTER) {
+ /* Cortex-A15: hold L2RSTDISABLE low */
+ reg &= ~CPUCFG_CX_CTRL_REG0_L2_RST_DISABLE_A15;
+ } else {
+ /* Cortex-A7: hold L1RSTDISABLE and L2RSTDISABLE low */
+ reg &= ~CPUCFG_CX_CTRL_REG0_L1_RST_DISABLE_ALL;
+ reg &= ~CPUCFG_CX_CTRL_REG0_L2_RST_DISABLE_A7;
+ }
+ writel(reg, cpucfg_base + CPUCFG_CX_CTRL_REG0(cluster));
+
+ /* clear cluster power gate */
+ reg = readl(prcm_base + PRCM_PWROFF_GATING_REG(cluster));
+ reg &= ~PRCM_PWROFF_GATING_REG_CLUSTER;
+ writel(reg, prcm_base + PRCM_PWROFF_GATING_REG(cluster));
+ udelay(20);
+
+ /* de-assert cluster resets */
+ reg = readl(cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
+ reg |= CPUCFG_CX_RST_CTRL_DBG_SOC_RST;
+ reg |= CPUCFG_CX_RST_CTRL_H_RST;
+ reg |= CPUCFG_CX_RST_CTRL_L2_RST;
+ writel(reg, cpucfg_base + CPUCFG_CX_RST_CTRL(cluster));
+
+ /* de-assert ACINACTM */
+ reg = readl(cpucfg_base + CPUCFG_CX_CTRL_REG1(cluster));
+ reg &= ~CPUCFG_CX_CTRL_REG1_ACINACTM;
+ writel(reg, cpucfg_base + CPUCFG_CX_CTRL_REG1(cluster));
+
+ return 0;
+}
+
+static void sunxi_cpu_cache_disable(void)
+{
+ /* Disable and flush the local CPU cache. */
+ v7_exit_coherency_flush(louis);
+}
+
+/*
+ * This bit is shared between the initial mcpm_sync_init call to enable
+ * CCI-400 and proper cluster cache disable before power down.
+ */
+static void sunxi_cluster_cache_disable_without_axi(void)
+{
+ if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A15) {
+ /*
+ * On the Cortex-A15 we need to disable
+ * L2 prefetching before flushing the cache.
+ */
+ asm volatile(
+ "mcr p15, 1, %0, c15, c0, 3\n"
+ "isb\n"
+ "dsb"
+ : : "r" (0x400));
+ }
+
+ /* Flush all cache levels for this cluster. */
+ v7_exit_coherency_flush(all);
+
+ /*
+ * Disable cluster-level coherency by masking
+ * incoming snoops and DVM messages:
+ */
+ cci_disable_port_by_cpu(read_cpuid_mpidr());
+}
+
+static void sunxi_cluster_cache_disable(void)
+{
+ unsigned int cluster = MPIDR_AFFINITY_LEVEL(read_cpuid_mpidr(), 1);
+ u32 reg;
+
+ pr_info("%s: cluster %u\n", __func__, cluster);
+
+ sunxi_cluster_cache_disable_without_axi();
+
+ /* last man standing, assert ACINACTM */
+ reg = readl(cpucfg_base + CPUCFG_CX_CTRL_REG1(cluster));
+ reg |= CPUCFG_CX_CTRL_REG1_ACINACTM;
+ writel(reg, cpucfg_base + CPUCFG_CX_CTRL_REG1(cluster));
+}
+
+static const struct mcpm_platform_ops sunxi_power_ops = {
+ .cpu_powerup = sunxi_cpu_powerup,
+ .cluster_powerup = sunxi_cluster_powerup,
+ .cpu_cache_disable = sunxi_cpu_cache_disable,
+ .cluster_cache_disable = sunxi_cluster_cache_disable,
+};
+
+/*
+ * Enable cluster-level coherency, in preparation for turning on the MMU.
+ *
+ * Also enable regional clock gating and L2 data latency settings for
+ * Cortex-A15.
+ */
+static void __naked sunxi_power_up_setup(unsigned int affinity_level)
+{
+ asm volatile (
+ "mrc p15, 0, r1, c0, c0, 0\n"
+ "movw r2, #" __stringify(ARM_CPU_PART_MASK & 0xffff) "\n"
+ "movt r2, #" __stringify(ARM_CPU_PART_MASK >> 16) "\n"
+ "and r1, r1, r2\n"
+ "movw r2, #" __stringify(ARM_CPU_PART_CORTEX_A15 & 0xffff) "\n"
+ "movt r2, #" __stringify(ARM_CPU_PART_CORTEX_A15 >> 16) "\n"
+ "cmp r1, r2\n"
+ "bne not_a15\n"
+
+ /* The following is Cortex-A15 specific */
+
+ /* L2CTRL: Enable CPU regional clock gates */
+ "mrc p15, 1, r1, c15, c0, 4\n"
+ "orr r1, r1, #(0x1<<31)\n"
+ "mcr p15, 1, r1, c15, c0, 4\n"
+
+ /* L2ACTLR */
+ "mrc p15, 1, r1, c15, c0, 0\n"
+ /* Enable L2, GIC, and Timer regional clock gates */
+ "orr r1, r1, #(0x1<<26)\n"
+ /* Disable clean/evict from being pushed to external */
+ "orr r1, r1, #(0x1<<3)\n"
+ "mcr p15, 1, r1, c15, c0, 0\n"
+
+ /* L2 data RAM latency */
+ "mrc p15, 1, r1, c9, c0, 2\n"
+ "bic r1, r1, #(0x7<<0)\n"
+ "orr r1, r1, #(0x3<<0)\n"
+ "mcr p15, 1, r1, c9, c0, 2\n"
+
+ /* End of Cortex-A15 specific setup */
+ "not_a15:\n"
+
+ "cmp r0, #1\n"
+ "bxne lr\n"
+ "b cci_enable_port_for_self"
+ );
+}
+
+static void sunxi_mcpm_setup_entry_point(void)
+{
+ __raw_writel(virt_to_phys(mcpm_entry_point),
+ prcm_base + PRCM_CPU_SOFT_ENTRY_REG);
+}
+
+static int __init sunxi_mcpm_init(void)
+{
+ struct device_node *node;
+ int ret;
+
+ if (!of_machine_is_compatible("allwinner,sun9i-a80"))
+ return -ENODEV;
+
+ if (!cci_probed())
+ return -ENODEV;
+
+ node = of_find_compatible_node(NULL, NULL,
+ "allwinner,sun9i-a80-cpucfg");
+ if (!node)
+ return -ENODEV;
+
+ cpucfg_base = of_iomap(node, 0);
+ of_node_put(node);
+ if (!cpucfg_base) {
+ pr_err("%s: failed to map CPUCFG registers\n", __func__);
+ return -ENOMEM;
+ }
+
+ node = of_find_compatible_node(NULL, NULL,
+ "allwinner,sun9i-a80-prcm");
+ if (!node)
+ return -ENODEV;
+
+ prcm_base = of_iomap(node, 0);
+ of_node_put(node);
+ if (!prcm_base) {
+ pr_err("%s: failed to map PRCM registers\n", __func__);
+ iounmap(prcm_base);
+ return -ENOMEM;
+ }
+
+ ret = mcpm_platform_register(&sunxi_power_ops);
+ if (!ret)
+ ret = mcpm_sync_init(sunxi_power_up_setup);
+ if (!ret)
+ /* do not disable AXI master as no one will re-enable it */
+ ret = mcpm_loopback(sunxi_cluster_cache_disable_without_axi);
+ if (ret) {
+ iounmap(cpucfg_base);
+ iounmap(prcm_base);
+ return ret;
+ }
+
+ mcpm_smp_set_ops();
+
+ pr_info("sunxi MCPM support installed\n");
+
+ sunxi_mcpm_setup_entry_point();
+
+ return ret;
+}
+
+early_initcall(sunxi_mcpm_init);
--
2.11.0
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