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@xxxxxxxxxxxx>
---
arch/arm/mach-bcm/Kconfig | 2 +
arch/arm/mach-bcm/Makefile | 8 +-
arch/arm/mach-bcm/bcm_nsp.h | 19 ++++
arch/arm/mach-bcm/headsmp.S | 37 ++++++++
arch/arm/mach-bcm/{kona_smp.c => platsmp.c} | 142 ++++++++++++++++++++++++++--
5 files changed, 197 insertions(+), 11 deletions(-)
create mode 100644 arch/arm/mach-bcm/bcm_nsp.h
create mode 100644 arch/arm/mach-bcm/headsmp.S
rename arch/arm/mach-bcm/{kona_smp.c => platsmp.c} (63%)
diff --git a/arch/arm/mach-bcm/Kconfig b/arch/arm/mach-bcm/Kconfig
index 1679fa4..2e9dbb5 100644
--- a/arch/arm/mach-bcm/Kconfig
+++ b/arch/arm/mach-bcm/Kconfig
@@ -40,6 +40,8 @@ config ARCH_BCM_NSP
select ARCH_BCM_IPROC
select ARM_ERRATA_754322
select ARM_ERRATA_775420
+ select ARM_ERRATA_764369 if SMP
+ select HAVE_SMP
help
Support for Broadcom Northstar Plus SoC.
Broadcom Northstar Plus family of SoCs are used for switching control
diff --git a/arch/arm/mach-bcm/Makefile b/arch/arm/mach-bcm/Makefile
index 892261f..36a4ca30 100644
--- a/arch/arm/mach-bcm/Makefile
+++ b/arch/arm/mach-bcm/Makefile
@@ -14,7 +14,11 @@
obj-$(CONFIG_ARCH_BCM_CYGNUS) += bcm_cygnus.o
# Northstar Plus
-obj-$(CONFIG_ARCH_BCM_NSP) += bcm_nsp.o
+obj-$(CONFIG_ARCH_BCM_NSP) += bcm_nsp.o
+
+ifeq ($(CONFIG_ARCH_BCM_NSP),y)
+obj-$(CONFIG_SMP) += headsmp.o platsmp.o
+endif
# BCM281XX
obj-$(CONFIG_ARCH_BCM_281XX) += board_bcm281xx.o
@@ -23,7 +27,7 @@ obj-$(CONFIG_ARCH_BCM_281XX) += board_bcm281xx.o
obj-$(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
diff --git a/arch/arm/mach-bcm/bcm_nsp.h b/arch/arm/mach-bcm/bcm_nsp.h
new file mode 100644
index 0000000..58e1e80
--- /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 */
diff --git a/arch/arm/mach-bcm/headsmp.S b/arch/arm/mach-bcm/headsmp.S
new file mode 100644
index 0000000..0da13b2
--- /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)
diff --git a/arch/arm/mach-bcm/kona_smp.c b/arch/arm/mach-bcm/platsmp.c
similarity index 63%
rename from arch/arm/mach-bcm/kona_smp.c
rename to arch/arm/mach-bcm/platsmp.c
index 66a0465..619030e 100644
--- a/arch/arm/mach-bcm/kona_smp.c
+++ b/arch/arm/mach-bcm/platsmp.c
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2014 Broadcom Corporation
+ * Copyright (C) 2014-2015 Broadcom Corporation
* Copyright 2014 Linaro Limited
*
* This program is free software; you can redistribute it and/or
@@ -12,16 +12,23 @@
* GNU General Public License for more details.
*/
-#include <linux/init.h>
+#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
@@ -34,6 +41,24 @@
/* 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
*
@@ -75,6 +100,51 @@ static int __init scu_a9_enable(void)
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 };
@@ -95,11 +165,11 @@ static void __init bcm_smp_prepare_cpus(unsigned int max_cpus)
/*
* 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
+ * 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_err("%s: missing/invalid " OF_SECONDARY_BOOT " property\n",
+ pr_warn("%s: missing/invalid " OF_SECONDARY_BOOT " property\n",
node->name);
ret = -ENOENT; /* Arrange to disable SMP */
goto out;
@@ -115,7 +185,6 @@ 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);
}
@@ -139,7 +208,7 @@ out:
* - 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)
+static int kona_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
void __iomem *boot_reg;
phys_addr_t boot_func;
@@ -162,7 +231,7 @@ static int bcm_boot_secondary(unsigned int cpu, struct task_struct *idle)
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;
+ return -ENOMEM;
}
/*
@@ -191,12 +260,67 @@ static int bcm_boot_secondary(unsigned int cpu, struct task_struct *idle)
pr_err("timeout waiting for cpu %u to start\n", cpu_id);
- return -ENOSYS;
+ 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 = bcm_boot_secondary,
+ .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);
--
2.1.0
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