ARCv2: SMP: Support ARConnect (MCIP) for Inter-Core-Interrupts et al

Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

1 files changed, 117 insertions, 0 deletions

diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c
new file mode 100644
index 000000000000..e6ad6e64440a
--- /dev/null
+++ b/arch/arc/kernel/mcip.c
@@ -0,0 +1,117 @@
+/*
+ * ARC ARConnect (MultiCore IP) support (formerly known as MCIP)
+ *
+ * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
+ *
+ * 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.
+ */
+
+#include <linux/smp.h>
+#include <linux/irq.h>
+#include <linux/spinlock.h>
+#include <asm/mcip.h>
+
+static char smp_cpuinfo_buf[128];
+
+static DEFINE_RAW_SPINLOCK(mcip_lock);
+
+
+/*
+ * Any SMP specific init any CPU does when it comes up.
+ * Here we setup the CPU to enable Inter-Processor-Interrupts
+ * Called for each CPU
+ * -Master      : init_IRQ()
+ * -Other(s)    : start_kernel_secondary()
+ */
+void mcip_init_smp(unsigned int cpu)
+{
+	smp_ipi_irq_setup(cpu, IPI_IRQ);
+}
+
+static void mcip_ipi_send(int cpu)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&mcip_lock, flags);
+	__mcip_cmd(CMD_INTRPT_GENERATE_IRQ, cpu);
+	raw_spin_unlock_irqrestore(&mcip_lock, flags);
+}
+
+static void mcip_ipi_clear(int irq)
+{
+	unsigned int cpu;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&mcip_lock, flags);
+
+	/* Who sent the IPI */
+	__mcip_cmd(CMD_INTRPT_CHECK_SOURCE, 0);
+
+	cpu = read_aux_reg(ARC_REG_MCIP_READBACK);	/* 1,2,4,8... */
+
+	__mcip_cmd(CMD_INTRPT_GENERATE_ACK, __ffs(cpu)); /* 0,1,2,3... */
+
+	raw_spin_unlock_irqrestore(&mcip_lock, flags);
+}
+
+volatile int wake_flag;
+
+static void mcip_wakeup_cpu(int cpu, unsigned long pc)
+{
+	BUG_ON(cpu == 0);
+	wake_flag = cpu;
+}
+
+void arc_platform_smp_wait_to_boot(int cpu)
+{
+	while (wake_flag != cpu)
+		;
+
+	wake_flag = 0;
+	__asm__ __volatile__("j @first_lines_of_secondary	\n");
+}
+
+struct plat_smp_ops plat_smp_ops = {
+	.info		= smp_cpuinfo_buf,
+	.cpu_kick	= mcip_wakeup_cpu,
+	.ipi_send	= mcip_ipi_send,
+	.ipi_clear	= mcip_ipi_clear,
+};
+
+void mcip_init_early_smp(void)
+{
+#define IS_AVAIL1(var, str)    ((var) ? str : "")
+
+	struct mcip_bcr {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+		unsigned int pad3:8,
+			     idu:1, llm:1, num_cores:6,
+			     iocoh:1,  grtc:1, dbg:1, pad2:1,
+			     msg:1, sem:1, ipi:1, pad:1,
+			     ver:8;
+#else
+		unsigned int ver:8,
+			     pad:1, ipi:1, sem:1, msg:1,
+			     pad2:1, dbg:1, grtc:1, iocoh:1,
+			     num_cores:6, llm:1, idu:1,
+			     pad3:8;
+#endif
+	} mp;
+
+	READ_BCR(ARC_REG_MCIP_BCR, mp);
+
+	sprintf(smp_cpuinfo_buf,
+		"Extn [SMP]\t: ARConnect (v%d): %d cores with %s%s%s%s\n",
+		mp.ver, mp.num_cores,
+		IS_AVAIL1(mp.ipi, "IPI "),
+		IS_AVAIL1(mp.idu, "IDU "),
+		IS_AVAIL1(mp.dbg, "DEBUG "),
+		IS_AVAIL1(mp.grtc, "GRTC"));
+
+	if (mp.dbg) {
+		__mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, 0xf);
+		__mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xf, 0xf);
+	}
+}