[PATCH 2/5] ARM: shmobile: Add the R9A06G032 SMP enabler driver

Simon Horman
2018-07-20T12:05:33Z

From: Michel Pollet <michel.pollet@bp.renesas.com>

The Renesas R9A06G032 second CA7 is parked in a ROM pen at boot time, it
equires a special enable method to get it started.

Signed-off-by: Michel Pollet <michel.pollet@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
drivers/soc/renesas/Makefile | 1 +
drivers/soc/renesas/r9a06g032-smp.c | 96 +++++++++++++++++++++++++++++++++++++
2 files changed, 97 insertions(+)
create mode 100644 drivers/soc/renesas/r9a06g032-smp.c

diff --git a/drivers/soc/renesas/Makefile b/drivers/soc/renesas/Makefile
index 7dc0f20d7907..44a0d6b10192 100644
--- a/drivers/soc/renesas/Makefile
+++ b/drivers/soc/renesas/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_SYSC_R8A77970) += r8a77970-sysc.o
obj-$(CONFIG_SYSC_R8A77980) += r8a77980-sysc.o
obj-$(CONFIG_SYSC_R8A77990) += r8a77990-sysc.o
obj-$(CONFIG_SYSC_R8A77995) += r8a77995-sysc.o
+obj-$(CONFIG_ARCH_R9A06G032) += r9a06g032-smp.o

# Family
obj-$(CONFIG_RST_RCAR) += rcar-rst.o
diff --git a/drivers/soc/renesas/r9a06g032-smp.c b/drivers/soc/renesas/r9a06g032-smp.c
new file mode 100644
index 000000000000..a1926e8d73f2
--- /dev/null
+++ b/drivers/soc/renesas/r9a06g032-smp.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * R9A06G032 Second CA7 enabler.
+ *
+ * Copyright (C) 2018 Renesas Electronics Europe Limited
+ *
+ * Michel Pollet <michel.pollet@bp.renesas.com>, <buserror@gmail.com>
+ * Derived from actions,s500-smp
+ */
+
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/smp.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
+r9a06g032_smp_boot_secondary(unsigned int cpu,
+ struct task_struct *idle)
+{
+ if (!cpu_bootaddr)
+ return -ENODEV;
+
+ spin_lock(&cpu_lock);
+
+ writel(__pa_symbol(secondary_startup), cpu_bootaddr);
+ arch_send_wakeup_ipi_mask(cpumask_of(cpu));
+
+ spin_unlock(&cpu_lock);
+
+ return 0;
+}
+
+static void __init r9a06g032_smp_prepare_cpus(unsigned int max_cpus)
+{
+ struct device_node *dn;
+ int ret = -EINVAL, dns;
+ 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.
+ * The bootloader *does* change this property.
+ * Note: The property can be either 64 or 32 bits, so handle both cases
+ */
+ if (of_find_property(dn, "cpu-release-addr", &dns)) {
+ if (dns == sizeof(u64)) {
+ u64 temp;
+
+ ret = of_property_read_u64(dn,
+ "cpu-release-addr", &temp);
+ bootaddr = temp;
+ } else {
+ ret = of_property_read_u32(dn,
+ "cpu-release-addr",
+ &bootaddr);
+ }
+ }
+ of_node_put(dn);
+ if (ret) {
+ pr_err("CPU#1: invalid cpu-release-addr property\n");
+ return;
+ }
+ pr_info("CPU#1: cpu-release-addr %08x\n", bootaddr);
+
+ cpu_bootaddr = ioremap(bootaddr, sizeof(bootaddr));
+}
+
+static const struct smp_operations r9a06g032_smp_ops __initconst = {
+ .smp_prepare_cpus = r9a06g032_smp_prepare_cpus,
+ .smp_boot_secondary = r9a06g032_smp_boot_secondary,
+};
+
+CPU_METHOD_OF_DECLARE(r9a06g032_smp,
+ "renesas,r9a06g032-smp", &r9a06g032_smp_ops);
--
2.11.0