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openwrtv4/target/linux/bcm53xx/patches-4.1/130-ARM-BCM-Add-SMP-support-for-Broadcom-NSP.patch
Hauke Mehrtens 5682b0d954 bcm53xx: use Broadcom's proposed SMP implementation 
This replaces our SMP implementation with a very similar version which
is Broadcom currently trying to get into mainline kernel.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

SVN-Revision: 47247
2015-10-23 22:29:05 +00:00

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From a0ad1511d5805b95ac4c454d7904c670a1696055 Mon Sep 17 00:00:00 2001
From: Kapil Hali <kapilh@broadcom.com>
Date: Wed, 14 Oct 2015 13:47:00 -0400
Subject: [PATCH] ARM: BCM: Add SMP support for Broadcom NSP
Add SMP support for Broadcom's Northstar Plus SoC,
cpu enable method and pen_release procedures. This
changes also consolidates iProc family's - BCM NSP
and BCM Kona, SMP handling in a common file.
Northstar Plus SoC is based on ARM Cortex-A9
revision r3p0 which requires configuration for ARM
Errata 764369 for SMP. This change adds the needed
configuration option.
Signed-off-by: Kapil Hali <kapilh@broadcom.com>
---
arch/arm/mach-bcm/Makefile | 2 +-
arch/arm/mach-bcm/bcm_nsp.h | 19 +++
arch/arm/mach-bcm/headsmp.S | 37 +++++
arch/arm/mach-bcm/kona_smp.c | 202 ---------------------------
arch/arm/mach-bcm/platsmp.c | 326 +++++++++++++++++++++++++++++++++++++++++++
5 files changed, 383 insertions(+), 203 deletions(-)
create mode 100644 arch/arm/mach-bcm/bcm_nsp.h
create mode 100644 arch/arm/mach-bcm/headsmp.S
delete mode 100644 arch/arm/mach-bcm/kona_smp.c
create mode 100644 arch/arm/mach-bcm/platsmp.c
--- a/arch/arm/mach-bcm/Makefile
+++ b/arch/arm/mach-bcm/Makefile
@@ -20,7 +20,7 @@ obj-$(CONFIG_ARCH_BCM_281XX) += board_bc
obj-$(CONFIG_ARCH_BCM_21664) += board_bcm21664.o
# BCM281XX and BCM21664 SMP support
-obj-$(CONFIG_ARCH_BCM_MOBILE_SMP) += kona_smp.o
+obj-$(CONFIG_ARCH_BCM_MOBILE_SMP) += platsmp.o
# BCM281XX and BCM21664 L2 cache control
obj-$(CONFIG_ARCH_BCM_MOBILE_L2_CACHE) += kona_l2_cache.o
--- /dev/null
+++ b/arch/arm/mach-bcm/bcm_nsp.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2015 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __BCM_NSP_H
+#define __BCM_NSP_H
+
+extern void nsp_secondary_startup(void);
+
+#endif /* __BCM_NSP_H */
--- /dev/null
+++ b/arch/arm/mach-bcm/headsmp.S
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2015 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/linkage.h>
+
+/*
+ * iProc specific entry point for secondary CPUs. This provides
+ * a "holding pen" into which all secondary cores are held until
+ * we are ready for them to initialise.
+ */
+ENTRY(nsp_secondary_startup)
+ mrc p15, 0, r0, c0, c0, 5
+ and r0, r0, #15
+ adr r4, 1f
+ ldmia r4, {r5, r6}
+ sub r4, r4, r5
+ add r6, r6, r4
+pen: ldr r7, [r6]
+ cmp r7, r0
+ bne pen
+
+ b secondary_startup
+
+1: .long .
+ .long pen_release
+
+ENDPROC(nsp_secondary_startup)
--- a/arch/arm/mach-bcm/kona_smp.c
+++ /dev/null
@@ -1,202 +0,0 @@
-/*
- * Copyright (C) 2014 Broadcom Corporation
- * Copyright 2014 Linaro Limited
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation version 2.
- *
- * This program is distributed "as is" WITHOUT ANY WARRANTY of any
- * kind, whether express or implied; without even the implied warranty
- * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- */
-
-#include <linux/init.h>
-#include <linux/errno.h>
-#include <linux/io.h>
-#include <linux/of.h>
-#include <linux/sched.h>
-
-#include <asm/smp.h>
-#include <asm/smp_plat.h>
-#include <asm/smp_scu.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"
-
-/* I/O address of register used to coordinate secondary core startup */
-static u32 secondary_boot;
-
-/*
- * 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 void __init bcm_smp_prepare_cpus(unsigned int max_cpus)
-{
- static cpumask_t only_cpu_0 = { CPU_BITS_CPU0 };
- struct device_node *node;
- int ret;
-
- BUG_ON(secondary_boot); /* We're called only once */
-
- /*
- * This function is only called via smp_ops->smp_prepare_cpu().
- * That only happens if a "/cpus" device tree node exists
- * and has an "enable-method" property that selects the SMP
- * operations defined herein.
- */
- node = of_find_node_by_path("/cpus");
- BUG_ON(!node);
-
- /*
- * Our secondary enable method requires a "secondary-boot-reg"
- * property to specify a register address used to request the
- * ROM code boot a secondary code. If we have any trouble
- * getting this we fall back to uniprocessor mode.
- */
- if (of_property_read_u32(node, OF_SECONDARY_BOOT, &secondary_boot)) {
- pr_err("%s: missing/invalid " OF_SECONDARY_BOOT " property\n",
- node->name);
- ret = -ENOENT; /* Arrange to disable SMP */
- goto out;
- }
-
- /*
- * Enable the SCU on Cortex A9 based SoCs. If -ENOENT is
- * returned, the SoC reported a uniprocessor configuration.
- * We bail on any other error.
- */
- ret = scu_a9_enable();
-out:
- of_node_put(node);
- if (ret) {
- /* Update the CPU present map to reflect uniprocessor mode */
- BUG_ON(ret != -ENOENT);
- pr_warn("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 bcm_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;
-
- 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) {
- pr_err("required secondary boot register not specified\n");
- return -EINVAL;
- }
-
- boot_reg = ioremap_nocache((phys_addr_t)secondary_boot, sizeof(u32));
- if (!boot_reg) {
- pr_err("unable to map boot register for cpu %u\n", cpu_id);
- return -ENOSYS;
- }
-
- /*
- * Secondary cores will start in secondary_startup(),
- * defined in "arch/arm/kernel/head.S"
- */
- boot_func = virt_to_phys(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 -ENOSYS;
-}
-
-static struct smp_operations bcm_smp_ops __initdata = {
- .smp_prepare_cpus = bcm_smp_prepare_cpus,
- .smp_boot_secondary = bcm_boot_secondary,
-};
-CPU_METHOD_OF_DECLARE(bcm_smp_bcm281xx, "brcm,bcm11351-cpu-method",
- &bcm_smp_ops);
--- /dev/null
+++ b/arch/arm/mach-bcm/platsmp.c
@@ -0,0 +1,326 @@
+/*
+ * Copyright (C) 2014-2015 Broadcom Corporation
+ * Copyright 2014 Linaro Limited
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/cpumask.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/of.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+
+#include <asm/cacheflush.h>
+#include <asm/smp.h>
+#include <asm/smp_plat.h>
+#include <asm/smp_scu.h>
+
+#include "bcm_nsp.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"
+
+/* I/O address of register used to coordinate secondary core startup */
+static u32 secondary_boot;
+
+static DEFINE_SPINLOCK(boot_lock);
+
+/*
+ * Write pen_release in a way that is guaranteed to be visible to all
+ * observers, irrespective of whether they're taking part in coherency
+ * or not. This is necessary for the hotplug code to work reliably.
+ */
+static void write_pen_release(int val)
+{
+ pen_release = val;
+ /*
+ * Ensure write to pen_release is visible to the other cores,
+ * here - primary core
+ */
+ smp_wmb();
+ sync_cache_w(&pen_release);
+}
+
+/*
+ * 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 int nsp_write_lut(void (*secondary_startup) (void))
+{
+ void __iomem *sku_rom_lut;
+ phys_addr_t secondary_startup_phy;
+
+ if (!secondary_boot) {
+ pr_warn("required secondary boot register not specified\n");
+ return -EINVAL;
+ }
+
+ sku_rom_lut = ioremap_nocache((phys_addr_t)secondary_boot,
+ sizeof(secondary_boot));
+ if (!sku_rom_lut) {
+ pr_warn("unable to ioremap SKU-ROM LUT register\n");
+ return -ENOMEM;
+ }
+
+ secondary_startup_phy = virt_to_phys(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 nsp_secondary_init(unsigned int cpu)
+{
+ /*
+ * Let the primary cpu know we are out of holding pen.
+ */
+ write_pen_release(-1);
+
+ /*
+ * Synchronise with the boot thread.
+ */
+ spin_lock(&boot_lock);
+ spin_unlock(&boot_lock);
+}
+
+static void __init bcm_smp_prepare_cpus(unsigned int max_cpus)
+{
+ static cpumask_t only_cpu_0 = { CPU_BITS_CPU0 };
+ struct device_node *node;
+ int ret;
+
+ BUG_ON(secondary_boot); /* We're called only once */
+
+ /*
+ * This function is only called via smp_ops->smp_prepare_cpu().
+ * That only happens if a "/cpus" device tree node exists
+ * and has an "enable-method" property that selects the SMP
+ * operations defined herein.
+ */
+ node = of_find_node_by_path("/cpus");
+ BUG_ON(!node);
+
+ /*
+ * Our secondary enable method requires a "secondary-boot-reg"
+ * property to specify a register address used to request the
+ * ROM code boot a secondary core. If we have any trouble
+ * getting this we fall back to uniprocessor mode.
+ */
+ if (of_property_read_u32(node, OF_SECONDARY_BOOT, &secondary_boot)) {
+ pr_warn("%s: missing/invalid " OF_SECONDARY_BOOT " property\n",
+ node->name);
+ ret = -ENOENT; /* Arrange to disable SMP */
+ goto out;
+ }
+
+ /*
+ * Enable the SCU on Cortex A9 based SoCs. If -ENOENT is
+ * returned, the SoC reported a uniprocessor configuration.
+ * We bail on any other error.
+ */
+ ret = scu_a9_enable();
+out:
+ of_node_put(node);
+ if (ret) {
+ /* Update the CPU present map to reflect uniprocessor mode */
+ pr_warn("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;
+
+ 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) {
+ pr_err("required secondary boot register not specified\n");
+ return -EINVAL;
+ }
+
+ boot_reg = ioremap_nocache((phys_addr_t)secondary_boot, sizeof(u32));
+ 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 = virt_to_phys(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;
+}
+
+static int nsp_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ unsigned long timeout;
+ int ret;
+
+ /*
+ * After wake up, secondary core branches to the startup
+ * address programmed at SKU ROM LUT location.
+ */
+ ret = nsp_write_lut(nsp_secondary_startup);
+ if (ret) {
+ pr_err("unable to write startup addr to SKU ROM LUT\n");
+ goto out;
+ }
+
+ /*
+ * The secondary processor is waiting to be released from
+ * the holding pen - release it, then wait for it to flag
+ * that it has been released by resetting pen_release.
+ */
+ spin_lock(&boot_lock);
+
+ write_pen_release(cpu_logical_map(cpu));
+ /*
+ * Send an Event to wake up the secondary core which is in
+ * WFE state. Updated pen_release should also be visible to
+ * the secondary core.
+ */
+ dsb_sev();
+
+ timeout = jiffies + (1 * HZ);
+ while (time_before(jiffies, timeout)) {
+ /* Make sure loads on other CPU is visible */
+ smp_rmb();
+ if (pen_release == -1)
+ break;
+
+ udelay(10);
+ }
+
+ spin_unlock(&boot_lock);
+
+ ret = pen_release != -1 ? -ENXIO : 0;
+
+out:
+ return ret;
+}
+
+static struct smp_operations bcm_smp_ops __initdata = {
+ .smp_prepare_cpus = bcm_smp_prepare_cpus,
+ .smp_boot_secondary = kona_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(bcm_smp_bcm281xx, "brcm,bcm11351-cpu-method",
+ &bcm_smp_ops);
+
+struct smp_operations nsp_smp_ops __initdata = {
+ .smp_prepare_cpus = bcm_smp_prepare_cpus,
+ .smp_secondary_init = nsp_secondary_init,
+ .smp_boot_secondary = nsp_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(bcm_smp_nsp, "brcm,bcm-nsp-smp", &nsp_smp_ops);
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