Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / arm64 / kernel / smp_spin_table.c

diff --git a/kernel/arch/arm64/kernel/smp_spin_table.c b/kernel/arch/arm64/kernel/smp_spin_table.c
new file mode 100644 (file)
index 0000000..14944e5
--- /dev/null
+++ b/kernel/arch/arm64/kernel/smp_spin_table.c
@@ -0,0 +1,127 @@
+/*
+ * Spin Table SMP initialisation
+ *
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/smp.h>
+#include <linux/types.h>
+
+#include <asm/cacheflush.h>
+#include <asm/cpu_ops.h>
+#include <asm/cputype.h>
+#include <asm/io.h>
+#include <asm/smp_plat.h>
+
+extern void secondary_holding_pen(void);
+volatile unsigned long secondary_holding_pen_release = INVALID_HWID;
+
+static phys_addr_t cpu_release_addr[NR_CPUS];
+
+/*
+ * Write secondary_holding_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(u64 val)
+{
+       void *start = (void *)&secondary_holding_pen_release;
+       unsigned long size = sizeof(secondary_holding_pen_release);
+
+       secondary_holding_pen_release = val;
+       __flush_dcache_area(start, size);
+}
+
+
+static int smp_spin_table_cpu_init(struct device_node *dn, unsigned int cpu)
+{
+       /*
+        * Determine the address from which the CPU is polling.
+        */
+       if (of_property_read_u64(dn, "cpu-release-addr",
+                                &cpu_release_addr[cpu])) {
+               pr_err("CPU %d: missing or invalid cpu-release-addr property\n",
+                      cpu);
+
+               return -1;
+       }
+
+       return 0;
+}
+
+static int smp_spin_table_cpu_prepare(unsigned int cpu)
+{
+       __le64 __iomem *release_addr;
+
+       if (!cpu_release_addr[cpu])
+               return -ENODEV;
+
+       /*
+        * The cpu-release-addr may or may not be inside the linear mapping.
+        * As ioremap_cache will either give us a new mapping or reuse the
+        * existing linear mapping, we can use it to cover both cases. In
+        * either case the memory will be MT_NORMAL.
+        */
+       release_addr = ioremap_cache(cpu_release_addr[cpu],
+                                    sizeof(*release_addr));
+       if (!release_addr)
+               return -ENOMEM;
+
+       /*
+        * We write the release address as LE regardless of the native
+        * endianess of the kernel. Therefore, any boot-loaders that
+        * read this address need to convert this address to the
+        * boot-loader's endianess before jumping. This is mandated by
+        * the boot protocol.
+        */
+       writeq_relaxed(__pa(secondary_holding_pen), release_addr);
+       __flush_dcache_area((__force void *)release_addr,
+                           sizeof(*release_addr));
+
+       /*
+        * Send an event to wake up the secondary CPU.
+        */
+       sev();
+
+       iounmap(release_addr);
+
+       return 0;
+}
+
+static int smp_spin_table_cpu_boot(unsigned int cpu)
+{
+       /*
+        * Update the pen release flag.
+        */
+       write_pen_release(cpu_logical_map(cpu));
+
+       /*
+        * Send an event, causing the secondaries to read pen_release.
+        */
+       sev();
+
+       return 0;
+}
+
+const struct cpu_operations smp_spin_table_ops = {
+       .name           = "spin-table",
+       .cpu_init       = smp_spin_table_cpu_init,
+       .cpu_prepare    = smp_spin_table_cpu_prepare,
+       .cpu_boot       = smp_spin_table_cpu_boot,
+};