[PATCH v5 4/5] ARM: BCM: Add SMP support for Broadcom NSP

From: Kapil Hali
Date: Fri Dec 04 2015 - 15:25:04 EST


Add SMP support for Broadcom's Northstar Plus SoC
cpu enable method. This changes also consolidates
iProc family's - BCM NSP and BCM Kona, platform
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/{kona_smp.c => platsmp.c} | 64 ++++++++++++++++++++++++++++-
3 files changed, 71 insertions(+), 3 deletions(-)
rename arch/arm/mach-bcm/{kona_smp.c => platsmp.c} (81%)

diff --git a/arch/arm/mach-bcm/Kconfig b/arch/arm/mach-bcm/Kconfig
index 8c53c55..83765a0 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..5193a25 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) += 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/kona_smp.c b/arch/arm/mach-bcm/platsmp.c
similarity index 81%
rename from arch/arm/mach-bcm/kona_smp.c
rename to arch/arm/mach-bcm/platsmp.c
index 15af781..ea4201e 100644
--- a/arch/arm/mach-bcm/kona_smp.c
+++ b/arch/arm/mach-bcm/platsmp.c
@@ -12,12 +12,17 @@
* 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>
@@ -76,6 +81,36 @@ static int __init scu_a9_enable(void)
return 0;
}

+static int nsp_write_lut(void)
+{
+ void __iomem *sku_rom_lut;
+ phys_addr_t secondary_startup_phy;
+
+ if (!secondary_boot_addr) {
+ pr_warn("required secondary boot register not specified\n");
+ return -EINVAL;
+ }
+
+ sku_rom_lut = ioremap_nocache((phys_addr_t)secondary_boot_addr,
+ sizeof(secondary_boot_addr));
+ 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 __init bcm_smp_prepare_cpus(unsigned int max_cpus)
{
static cpumask_t only_cpu_0 = { CPU_BITS_CPU0 };
@@ -220,9 +255,36 @@ static int kona_boot_secondary(unsigned int cpu, struct task_struct *idle)
return -ENXIO;
}

+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();
+ 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 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_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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