openwrt/target/linux/bcm53xx/patches-4.3/130-ARM-BCM-Add-SMP-support-for-Broadcom-NSP.patch

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);