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Subject[RFC 3/3] arm: shmobile: Add the RZ/N1D SMP enabler driver.
Date
The Renesas RZ/N1D second CA7 is parked in a ROM pen at boot time, it
requires a special enable method to get it started at boot time.

Signed-off-by: Michel Pollet <michel.pollet@bp.renesas.com>
---
arch/arm/mach-shmobile/Makefile | 1 +
arch/arm/mach-shmobile/smp-r9a06g032.c | 87 ++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+)
create mode 100644 arch/arm/mach-shmobile/smp-r9a06g032.c

diff --git a/arch/arm/mach-shmobile/Makefile b/arch/arm/mach-shmobile/Makefile
index 1939f52..d7fc98f 100644
--- a/arch/arm/mach-shmobile/Makefile
+++ b/arch/arm/mach-shmobile/Makefile
@@ -34,6 +34,7 @@ smp-$(CONFIG_ARCH_SH73A0) += smp-sh73a0.o headsmp-scu.o platsmp-scu.o
smp-$(CONFIG_ARCH_R8A7779) += smp-r8a7779.o headsmp-scu.o platsmp-scu.o
smp-$(CONFIG_ARCH_R8A7790) += smp-r8a7790.o
smp-$(CONFIG_ARCH_R8A7791) += smp-r8a7791.o
+smp-$(CONFIG_ARCH_R9A06G032) += smp-r9a06g032.o
smp-$(CONFIG_ARCH_EMEV2) += smp-emev2.o headsmp-scu.o platsmp-scu.o

# PM objects
diff --git a/arch/arm/mach-shmobile/smp-r9a06g032.c b/arch/arm/mach-shmobile/smp-r9a06g032.c
new file mode 100644
index 0000000..59ec287
--- /dev/null
+++ b/arch/arm/mach-shmobile/smp-r9a06g032.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RZ/N1D Second CA7 enabler.
+ *
+ * Copyright (C) 2018 Renesas Electronics Europe Limited
+ *
+ * Michel Pollet <michel.pollet@bp.renesas.com>, <buserror@gmail.com>
+ * Derived from action,s500-smp
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/smp.h>
+#include <asm/cacheflush.h>
+#include <asm/smp_plat.h>
+#include <asm/smp_scu.h>
+
+/*
+ * The second CPU is parked in ROM at boot time. It requires waking it after
+ * writing an address into the BOOTADDR register of sysctrl.
+ *
+ * So the default value of the "cpu-release-addr" corresponds to BOOTADDR...
+ *
+ * *However* the BOOTADDR register is not available when the kernel
+ * starts in NONSEC mode.
+ *
+ * So for NONSEC mode, the bootloader re-parks the second CPU into a pen
+ * in SRAM, and changes the "cpu-release-addr" of linux's DT to a SRAM address,
+ * which is not restricted.
+ */
+
+static void __iomem *cpu_bootaddr;
+
+static DEFINE_SPINLOCK(cpu_lock);
+
+static int rzn1_smp_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+ if (!cpu_bootaddr)
+ return -ENODEV;
+
+ spin_lock(&cpu_lock);
+
+ writel(virt_to_phys(secondary_startup), cpu_bootaddr);
+ arch_send_wakeup_ipi_mask(cpumask_of(cpu));
+
+ spin_unlock(&cpu_lock);
+
+ return 0;
+}
+
+static void __init rzn1_smp_prepare_cpus(unsigned int max_cpus)
+{
+ struct device_node *dn;
+ int ret;
+ u32 bootaddr;
+
+ dn = of_get_cpu_node(1, NULL);
+ if (!dn) {
+ pr_err("CPU#1: missing device tree node\n");
+ return;
+ }
+ /*
+ * Determine the address from which the CPU is polling.
+ */
+ ret = of_property_read_u32(dn, "cpu-release-addr", &bootaddr);
+ if (ret)
+ pr_err("CPU#1: invalid cpu-release-addr property\n");
+
+ of_node_put(dn);
+ /* The bootloader *does* change this property */
+ pr_info("CPU#1: cpu-release-addr %08x\n", (u32)bootaddr);
+
+ if (!bootaddr)
+ return;
+
+ cpu_bootaddr = ioremap(bootaddr, sizeof(bootaddr));
+ if (!cpu_bootaddr)
+ pr_err("CPU#1: cpu-release-addr map failed\n");
+}
+
+static const struct smp_operations rzn1_smp_ops __initconst = {
+ .smp_prepare_cpus = rzn1_smp_prepare_cpus,
+ .smp_boot_secondary = rzn1_smp_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(rzn1_smp, "renesas,r9a06g032-smp", &rzn1_smp_ops);
--
2.7.4
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