v4.19.13 snapshot.
diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c
new file mode 100644
index 0000000..5fe84e4
--- /dev/null
+++ b/arch/arc/kernel/mcip.c
@@ -0,0 +1,376 @@
+/*
+ * 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/irqchip/chained_irq.h>
+#include <linux/spinlock.h>
+#include <soc/arc/mcip.h>
+#include <asm/irqflags-arcv2.h>
+#include <asm/setup.h>
+
+static DEFINE_RAW_SPINLOCK(mcip_lock);
+
+#ifdef CONFIG_SMP
+
+static char smp_cpuinfo_buf[128];
+
+/*
+ * Set mask to halt GFRC if any online core in SMP cluster is halted.
+ * Only works for ARC HS v3.0+, on earlier versions has no effect.
+ */
+static void mcip_update_gfrc_halt_mask(int cpu)
+{
+ struct bcr_generic gfrc;
+ unsigned long flags;
+ u32 gfrc_halt_mask;
+
+ READ_BCR(ARC_REG_GFRC_BUILD, gfrc);
+
+ /*
+ * CMD_GFRC_SET_CORE and CMD_GFRC_READ_CORE commands were added in
+ * GFRC 0x3 version.
+ */
+ if (gfrc.ver < 0x3)
+ return;
+
+ raw_spin_lock_irqsave(&mcip_lock, flags);
+
+ __mcip_cmd(CMD_GFRC_READ_CORE, 0);
+ gfrc_halt_mask = read_aux_reg(ARC_REG_MCIP_READBACK);
+ gfrc_halt_mask |= BIT(cpu);
+ __mcip_cmd_data(CMD_GFRC_SET_CORE, 0, gfrc_halt_mask);
+
+ raw_spin_unlock_irqrestore(&mcip_lock, flags);
+}
+
+static void mcip_update_debug_halt_mask(int cpu)
+{
+ u32 mcip_mask = 0;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&mcip_lock, flags);
+
+ /*
+ * mcip_mask is same for CMD_DEBUG_SET_SELECT and CMD_DEBUG_SET_MASK
+ * commands. So read it once instead of reading both CMD_DEBUG_READ_MASK
+ * and CMD_DEBUG_READ_SELECT.
+ */
+ __mcip_cmd(CMD_DEBUG_READ_SELECT, 0);
+ mcip_mask = read_aux_reg(ARC_REG_MCIP_READBACK);
+
+ mcip_mask |= BIT(cpu);
+
+ __mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, mcip_mask);
+ /*
+ * Parameter specified halt cause:
+ * STATUS32[H]/actionpoint/breakpoint/self-halt
+ * We choose all of them (0xF).
+ */
+ __mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xF, mcip_mask);
+
+ raw_spin_unlock_irqrestore(&mcip_lock, flags);
+}
+
+static void mcip_setup_per_cpu(int cpu)
+{
+ struct mcip_bcr mp;
+
+ READ_BCR(ARC_REG_MCIP_BCR, mp);
+
+ smp_ipi_irq_setup(cpu, IPI_IRQ);
+ smp_ipi_irq_setup(cpu, SOFTIRQ_IRQ);
+
+ /* Update GFRC halt mask as new CPU came online */
+ if (mp.gfrc)
+ mcip_update_gfrc_halt_mask(cpu);
+
+ /* Update MCIP debug mask as new CPU came online */
+ if (mp.dbg)
+ mcip_update_debug_halt_mask(cpu);
+}
+
+static void mcip_ipi_send(int cpu)
+{
+ unsigned long flags;
+ int ipi_was_pending;
+
+ /* ARConnect can only send IPI to others */
+ if (unlikely(cpu == raw_smp_processor_id())) {
+ arc_softirq_trigger(SOFTIRQ_IRQ);
+ return;
+ }
+
+ raw_spin_lock_irqsave(&mcip_lock, flags);
+
+ /*
+ * If receiver already has a pending interrupt, elide sending this one.
+ * Linux cross core calling works well with concurrent IPIs
+ * coalesced into one
+ * see arch/arc/kernel/smp.c: ipi_send_msg_one()
+ */
+ __mcip_cmd(CMD_INTRPT_READ_STATUS, cpu);
+ ipi_was_pending = read_aux_reg(ARC_REG_MCIP_READBACK);
+ if (!ipi_was_pending)
+ __mcip_cmd(CMD_INTRPT_GENERATE_IRQ, cpu);
+
+ raw_spin_unlock_irqrestore(&mcip_lock, flags);
+}
+
+static void mcip_ipi_clear(int irq)
+{
+ unsigned int cpu, c;
+ unsigned long flags;
+
+ if (unlikely(irq == SOFTIRQ_IRQ)) {
+ arc_softirq_clear(irq);
+ return;
+ }
+
+ 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... */
+
+ /*
+ * In rare case, multiple concurrent IPIs sent to same target can
+ * possibly be coalesced by MCIP into 1 asserted IRQ, so @cpus can be
+ * "vectored" (multiple bits sets) as opposed to typical single bit
+ */
+ do {
+ c = __ffs(cpu); /* 0,1,2,3 */
+ __mcip_cmd(CMD_INTRPT_GENERATE_ACK, c);
+ cpu &= ~(1U << c);
+ } while (cpu);
+
+ raw_spin_unlock_irqrestore(&mcip_lock, flags);
+}
+
+static void mcip_probe_n_setup(void)
+{
+ struct mcip_bcr 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.gfrc, "GFRC"));
+
+ cpuinfo_arc700[0].extn.gfrc = mp.gfrc;
+}
+
+struct plat_smp_ops plat_smp_ops = {
+ .info = smp_cpuinfo_buf,
+ .init_early_smp = mcip_probe_n_setup,
+ .init_per_cpu = mcip_setup_per_cpu,
+ .ipi_send = mcip_ipi_send,
+ .ipi_clear = mcip_ipi_clear,
+};
+
+#endif
+
+/***************************************************************************
+ * ARCv2 Interrupt Distribution Unit (IDU)
+ *
+ * Connects external "COMMON" IRQs to core intc, providing:
+ * -dynamic routing (IRQ affinity)
+ * -load balancing (Round Robin interrupt distribution)
+ * -1:N distribution
+ *
+ * It physically resides in the MCIP hw block
+ */
+
+#include <linux/irqchip.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+
+/*
+ * Set the DEST for @cmn_irq to @cpu_mask (1 bit per core)
+ */
+static void idu_set_dest(unsigned int cmn_irq, unsigned int cpu_mask)
+{
+ __mcip_cmd_data(CMD_IDU_SET_DEST, cmn_irq, cpu_mask);
+}
+
+static void idu_set_mode(unsigned int cmn_irq, unsigned int lvl,
+ unsigned int distr)
+{
+ union {
+ unsigned int word;
+ struct {
+ unsigned int distr:2, pad:2, lvl:1, pad2:27;
+ };
+ } data;
+
+ data.distr = distr;
+ data.lvl = lvl;
+ __mcip_cmd_data(CMD_IDU_SET_MODE, cmn_irq, data.word);
+}
+
+static void idu_irq_mask_raw(irq_hw_number_t hwirq)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&mcip_lock, flags);
+ __mcip_cmd_data(CMD_IDU_SET_MASK, hwirq, 1);
+ raw_spin_unlock_irqrestore(&mcip_lock, flags);
+}
+
+static void idu_irq_mask(struct irq_data *data)
+{
+ idu_irq_mask_raw(data->hwirq);
+}
+
+static void idu_irq_unmask(struct irq_data *data)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&mcip_lock, flags);
+ __mcip_cmd_data(CMD_IDU_SET_MASK, data->hwirq, 0);
+ raw_spin_unlock_irqrestore(&mcip_lock, flags);
+}
+
+static int
+idu_irq_set_affinity(struct irq_data *data, const struct cpumask *cpumask,
+ bool force)
+{
+ unsigned long flags;
+ cpumask_t online;
+ unsigned int destination_bits;
+ unsigned int distribution_mode;
+
+ /* errout if no online cpu per @cpumask */
+ if (!cpumask_and(&online, cpumask, cpu_online_mask))
+ return -EINVAL;
+
+ raw_spin_lock_irqsave(&mcip_lock, flags);
+
+ destination_bits = cpumask_bits(&online)[0];
+ idu_set_dest(data->hwirq, destination_bits);
+
+ if (ffs(destination_bits) == fls(destination_bits))
+ distribution_mode = IDU_M_DISTRI_DEST;
+ else
+ distribution_mode = IDU_M_DISTRI_RR;
+
+ idu_set_mode(data->hwirq, IDU_M_TRIG_LEVEL, distribution_mode);
+
+ raw_spin_unlock_irqrestore(&mcip_lock, flags);
+
+ return IRQ_SET_MASK_OK;
+}
+
+static void idu_irq_enable(struct irq_data *data)
+{
+ /*
+ * By default send all common interrupts to all available online CPUs.
+ * The affinity of common interrupts in IDU must be set manually since
+ * in some cases the kernel will not call irq_set_affinity() by itself:
+ * 1. When the kernel is not configured with support of SMP.
+ * 2. When the kernel is configured with support of SMP but upper
+ * interrupt controllers does not support setting of the affinity
+ * and cannot propagate it to IDU.
+ */
+ idu_irq_set_affinity(data, cpu_online_mask, false);
+ idu_irq_unmask(data);
+}
+
+static struct irq_chip idu_irq_chip = {
+ .name = "MCIP IDU Intc",
+ .irq_mask = idu_irq_mask,
+ .irq_unmask = idu_irq_unmask,
+ .irq_enable = idu_irq_enable,
+#ifdef CONFIG_SMP
+ .irq_set_affinity = idu_irq_set_affinity,
+#endif
+
+};
+
+static void idu_cascade_isr(struct irq_desc *desc)
+{
+ struct irq_domain *idu_domain = irq_desc_get_handler_data(desc);
+ struct irq_chip *core_chip = irq_desc_get_chip(desc);
+ irq_hw_number_t core_hwirq = irqd_to_hwirq(irq_desc_get_irq_data(desc));
+ irq_hw_number_t idu_hwirq = core_hwirq - FIRST_EXT_IRQ;
+
+ chained_irq_enter(core_chip, desc);
+ generic_handle_irq(irq_find_mapping(idu_domain, idu_hwirq));
+ chained_irq_exit(core_chip, desc);
+}
+
+static int idu_irq_map(struct irq_domain *d, unsigned int virq, irq_hw_number_t hwirq)
+{
+ irq_set_chip_and_handler(virq, &idu_irq_chip, handle_level_irq);
+ irq_set_status_flags(virq, IRQ_MOVE_PCNTXT);
+
+ return 0;
+}
+
+static const struct irq_domain_ops idu_irq_ops = {
+ .xlate = irq_domain_xlate_onecell,
+ .map = idu_irq_map,
+};
+
+/*
+ * [16, 23]: Statically assigned always private-per-core (Timers, WDT, IPI)
+ * [24, 23+C]: If C > 0 then "C" common IRQs
+ * [24+C, N]: Not statically assigned, private-per-core
+ */
+
+
+static int __init
+idu_of_init(struct device_node *intc, struct device_node *parent)
+{
+ struct irq_domain *domain;
+ int nr_irqs;
+ int i, virq;
+ struct mcip_bcr mp;
+ struct mcip_idu_bcr idu_bcr;
+
+ READ_BCR(ARC_REG_MCIP_BCR, mp);
+
+ if (!mp.idu)
+ panic("IDU not detected, but DeviceTree using it");
+
+ READ_BCR(ARC_REG_MCIP_IDU_BCR, idu_bcr);
+ nr_irqs = mcip_idu_bcr_to_nr_irqs(idu_bcr);
+
+ pr_info("MCIP: IDU supports %u common irqs\n", nr_irqs);
+
+ domain = irq_domain_add_linear(intc, nr_irqs, &idu_irq_ops, NULL);
+
+ /* Parent interrupts (core-intc) are already mapped */
+
+ for (i = 0; i < nr_irqs; i++) {
+ /* Mask all common interrupts by default */
+ idu_irq_mask_raw(i);
+
+ /*
+ * Return parent uplink IRQs (towards core intc) 24,25,.....
+ * this step has been done before already
+ * however we need it to get the parent virq and set IDU handler
+ * as first level isr
+ */
+ virq = irq_create_mapping(NULL, i + FIRST_EXT_IRQ);
+ BUG_ON(!virq);
+ irq_set_chained_handler_and_data(virq, idu_cascade_isr, domain);
+ }
+
+ __mcip_cmd(CMD_IDU_ENABLE, 0);
+
+ return 0;
+}
+IRQCHIP_DECLARE(arcv2_idu_intc, "snps,archs-idu-intc", idu_of_init);