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-rw-r--r--arch/arm/mach-bcm/platsmp.c339
1 files changed, 339 insertions, 0 deletions
diff --git a/arch/arm/mach-bcm/platsmp.c b/arch/arm/mach-bcm/platsmp.c
new file mode 100644
index 0000000000..c9db2a9006
--- /dev/null
+++ b/arch/arm/mach-bcm/platsmp.c
@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2014-2015 Broadcom Corporation
+ * Copyright 2014 Linaro Limited
+ */
+
+#include <linux/cpumask.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/irqchip/irq-bcm2836.h>
+#include <linux/jiffies.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/smp.h>
+
+#include <asm/cacheflush.h>
+#include <asm/smp.h>
+#include <asm/smp_plat.h>
+#include <asm/smp_scu.h>
+
+#include "platsmp.h"
+
+/* Size of mapped Cortex A9 SCU address space */
+#define CORTEX_A9_SCU_SIZE 0x58
+
+#define SECONDARY_TIMEOUT_NS NSEC_PER_MSEC /* 1 msec (in nanoseconds) */
+#define BOOT_ADDR_CPUID_MASK 0x3
+
+/* Name of device node property defining secondary boot register location */
+#define OF_SECONDARY_BOOT "secondary-boot-reg"
+#define MPIDR_CPUID_BITMASK 0x3
+
+/*
+ * Enable the Cortex A9 Snoop Control Unit
+ *
+ * By the time this is called we already know there are multiple
+ * cores present. We assume we're running on a Cortex A9 processor,
+ * so any trouble getting the base address register or getting the
+ * SCU base is a problem.
+ *
+ * Return 0 if successful or an error code otherwise.
+ */
+static int __init scu_a9_enable(void)
+{
+ unsigned long config_base;
+ void __iomem *scu_base;
+
+ if (!scu_a9_has_base()) {
+ pr_err("no configuration base address register!\n");
+ return -ENXIO;
+ }
+
+ /* Config base address register value is zero for uniprocessor */
+ config_base = scu_a9_get_base();
+ if (!config_base) {
+ pr_err("hardware reports only one core\n");
+ return -ENOENT;
+ }
+
+ scu_base = ioremap((phys_addr_t)config_base, CORTEX_A9_SCU_SIZE);
+ if (!scu_base) {
+ pr_err("failed to remap config base (%lu/%u) for SCU\n",
+ config_base, CORTEX_A9_SCU_SIZE);
+ return -ENOMEM;
+ }
+
+ scu_enable(scu_base);
+
+ iounmap(scu_base); /* That's the last we'll need of this */
+
+ return 0;
+}
+
+static u32 secondary_boot_addr_for(unsigned int cpu)
+{
+ u32 secondary_boot_addr = 0;
+ struct device_node *cpu_node = of_get_cpu_node(cpu, NULL);
+
+ if (!cpu_node) {
+ pr_err("Failed to find device tree node for CPU%u\n", cpu);
+ return 0;
+ }
+
+ if (of_property_read_u32(cpu_node,
+ OF_SECONDARY_BOOT,
+ &secondary_boot_addr))
+ pr_err("required secondary boot register not specified for CPU%u\n",
+ cpu);
+
+ of_node_put(cpu_node);
+
+ return secondary_boot_addr;
+}
+
+static int nsp_write_lut(unsigned int cpu)
+{
+ void __iomem *sku_rom_lut;
+ phys_addr_t secondary_startup_phy;
+ const u32 secondary_boot_addr = secondary_boot_addr_for(cpu);
+
+ if (!secondary_boot_addr)
+ return -EINVAL;
+
+ sku_rom_lut = ioremap((phys_addr_t)secondary_boot_addr,
+ sizeof(phys_addr_t));
+ if (!sku_rom_lut) {
+ pr_warn("unable to ioremap SKU-ROM LUT register for cpu %u\n", cpu);
+ return -ENOMEM;
+ }
+
+ secondary_startup_phy = __pa_symbol(secondary_startup);
+ BUG_ON(secondary_startup_phy > (phys_addr_t)U32_MAX);
+
+ writel_relaxed(secondary_startup_phy, sku_rom_lut);
+
+ /* Ensure the write is visible to the secondary core */
+ smp_wmb();
+
+ iounmap(sku_rom_lut);
+
+ return 0;
+}
+
+static void __init bcm_smp_prepare_cpus(unsigned int max_cpus)
+{
+ const cpumask_t only_cpu_0 = { CPU_BITS_CPU0 };
+
+ /* Enable the SCU on Cortex A9 based SoCs */
+ if (scu_a9_enable()) {
+ /* Update the CPU present map to reflect uniprocessor mode */
+ pr_warn("failed to enable A9 SCU - disabling SMP\n");
+ init_cpu_present(&only_cpu_0);
+ }
+}
+
+/*
+ * The ROM code has the secondary cores looping, waiting for an event.
+ * When an event occurs each core examines the bottom two bits of the
+ * secondary boot register. When a core finds those bits contain its
+ * own core id, it performs initialization, including computing its boot
+ * address by clearing the boot register value's bottom two bits. The
+ * core signals that it is beginning its execution by writing its boot
+ * address back to the secondary boot register, and finally jumps to
+ * that address.
+ *
+ * So to start a core executing we need to:
+ * - Encode the (hardware) CPU id with the bottom bits of the secondary
+ * start address.
+ * - Write that value into the secondary boot register.
+ * - Generate an event to wake up the secondary CPU(s).
+ * - Wait for the secondary boot register to be re-written, which
+ * indicates the secondary core has started.
+ */
+static int kona_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ void __iomem *boot_reg;
+ phys_addr_t boot_func;
+ u64 start_clock;
+ u32 cpu_id;
+ u32 boot_val;
+ bool timeout = false;
+ const u32 secondary_boot_addr = secondary_boot_addr_for(cpu);
+
+ cpu_id = cpu_logical_map(cpu);
+ if (cpu_id & ~BOOT_ADDR_CPUID_MASK) {
+ pr_err("bad cpu id (%u > %u)\n", cpu_id, BOOT_ADDR_CPUID_MASK);
+ return -EINVAL;
+ }
+
+ if (!secondary_boot_addr)
+ return -EINVAL;
+
+ boot_reg = ioremap((phys_addr_t)secondary_boot_addr,
+ sizeof(phys_addr_t));
+ if (!boot_reg) {
+ pr_err("unable to map boot register for cpu %u\n", cpu_id);
+ return -ENOMEM;
+ }
+
+ /*
+ * Secondary cores will start in secondary_startup(),
+ * defined in "arch/arm/kernel/head.S"
+ */
+ boot_func = __pa_symbol(secondary_startup);
+ BUG_ON(boot_func & BOOT_ADDR_CPUID_MASK);
+ BUG_ON(boot_func > (phys_addr_t)U32_MAX);
+
+ /* The core to start is encoded in the low bits */
+ boot_val = (u32)boot_func | cpu_id;
+ writel_relaxed(boot_val, boot_reg);
+
+ sev();
+
+ /* The low bits will be cleared once the core has started */
+ start_clock = local_clock();
+ while (!timeout && readl_relaxed(boot_reg) == boot_val)
+ timeout = local_clock() - start_clock > SECONDARY_TIMEOUT_NS;
+
+ iounmap(boot_reg);
+
+ if (!timeout)
+ return 0;
+
+ pr_err("timeout waiting for cpu %u to start\n", cpu_id);
+
+ return -ENXIO;
+}
+
+/* Cluster Dormant Control command to bring CPU into a running state */
+#define CDC_CMD 6
+#define CDC_CMD_OFFSET 0
+#define CDC_CMD_REG(cpu) (CDC_CMD_OFFSET + 4*(cpu))
+
+/*
+ * BCM23550 has a Cluster Dormant Control block that keeps the core in
+ * idle state. A command needs to be sent to the block to bring the CPU
+ * into running state.
+ */
+static int bcm23550_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ void __iomem *cdc_base;
+ struct device_node *dn;
+ char *name;
+ int ret;
+
+ /* Make sure a CDC node exists before booting the
+ * secondary core.
+ */
+ name = "brcm,bcm23550-cdc";
+ dn = of_find_compatible_node(NULL, NULL, name);
+ if (!dn) {
+ pr_err("unable to find cdc node\n");
+ return -ENODEV;
+ }
+
+ cdc_base = of_iomap(dn, 0);
+ of_node_put(dn);
+
+ if (!cdc_base) {
+ pr_err("unable to remap cdc base register\n");
+ return -ENOMEM;
+ }
+
+ /* Boot the secondary core */
+ ret = kona_boot_secondary(cpu, idle);
+ if (ret)
+ goto out;
+
+ /* Bring this CPU to RUN state so that nIRQ nFIQ
+ * signals are unblocked.
+ */
+ writel_relaxed(CDC_CMD, cdc_base + CDC_CMD_REG(cpu));
+
+out:
+ iounmap(cdc_base);
+
+ return ret;
+}
+
+static int nsp_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ int ret;
+
+ /*
+ * After wake up, secondary core branches to the startup
+ * address programmed at SKU ROM LUT location.
+ */
+ ret = nsp_write_lut(cpu);
+ if (ret) {
+ pr_err("unable to write startup addr to SKU ROM LUT\n");
+ goto out;
+ }
+
+ /* Send a CPU wakeup interrupt to the secondary core */
+ arch_send_wakeup_ipi_mask(cpumask_of(cpu));
+
+out:
+ return ret;
+}
+
+static int bcm2836_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ void __iomem *intc_base;
+ struct device_node *dn;
+ char *name;
+
+ name = "brcm,bcm2836-l1-intc";
+ dn = of_find_compatible_node(NULL, NULL, name);
+ if (!dn) {
+ pr_err("unable to find intc node\n");
+ return -ENODEV;
+ }
+
+ intc_base = of_iomap(dn, 0);
+ of_node_put(dn);
+
+ if (!intc_base) {
+ pr_err("unable to remap intc base register\n");
+ return -ENOMEM;
+ }
+
+ writel(virt_to_phys(secondary_startup),
+ intc_base + LOCAL_MAILBOX3_SET0 + 16 * cpu);
+
+ dsb(sy);
+ sev();
+
+ iounmap(intc_base);
+
+ return 0;
+}
+
+static const struct smp_operations kona_smp_ops __initconst = {
+ .smp_prepare_cpus = bcm_smp_prepare_cpus,
+ .smp_boot_secondary = kona_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(bcm_smp_bcm281xx, "brcm,bcm11351-cpu-method",
+ &kona_smp_ops);
+
+static const struct smp_operations bcm23550_smp_ops __initconst = {
+ .smp_boot_secondary = bcm23550_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(bcm_smp_bcm23550, "brcm,bcm23550",
+ &bcm23550_smp_ops);
+
+static const struct smp_operations nsp_smp_ops __initconst = {
+ .smp_prepare_cpus = bcm_smp_prepare_cpus,
+ .smp_boot_secondary = nsp_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(bcm_smp_nsp, "brcm,bcm-nsp-smp", &nsp_smp_ops);
+
+const struct smp_operations bcm2836_smp_ops __initconst = {
+ .smp_boot_secondary = bcm2836_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(bcm_smp_bcm2836, "brcm,bcm2836-smp", &bcm2836_smp_ops);