forked from Minki/linux
3ce0fefc51
The IDU intc is technically part of MCIP (Multi-core IP) hence
historically was only available in a SMP hardware build (and thus only
in a SMP kernel build). Now that hardware restriction has been lifted,
so a UP kernel needs to support it.
This requires breaking mcip.c into parts which are strictly SMP
(inter-core interrupts) and IDU which in reality is just another
intc and thus has no bearing on SMP.
This change allows IDU in UP builds and with a suitable device tree, we
can have the cascaded intc system
ARCv2 core intc <---> ARCv2 IDU intc <---> periperals
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
318 lines
7.7 KiB
C
318 lines
7.7 KiB
C
/*
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* ARC ARConnect (MultiCore IP) support (formerly known as MCIP)
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*
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* Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/smp.h>
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#include <linux/irq.h>
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#include <linux/spinlock.h>
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#include <asm/irqflags-arcv2.h>
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#include <asm/mcip.h>
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#include <asm/setup.h>
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static DEFINE_RAW_SPINLOCK(mcip_lock);
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#ifdef CONFIG_SMP
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static char smp_cpuinfo_buf[128];
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static void mcip_setup_per_cpu(int cpu)
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{
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smp_ipi_irq_setup(cpu, IPI_IRQ);
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smp_ipi_irq_setup(cpu, SOFTIRQ_IRQ);
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}
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static void mcip_ipi_send(int cpu)
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{
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unsigned long flags;
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int ipi_was_pending;
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/* ARConnect can only send IPI to others */
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if (unlikely(cpu == raw_smp_processor_id())) {
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arc_softirq_trigger(SOFTIRQ_IRQ);
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return;
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}
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raw_spin_lock_irqsave(&mcip_lock, flags);
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/*
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* If receiver already has a pending interrupt, elide sending this one.
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* Linux cross core calling works well with concurrent IPIs
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* coalesced into one
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* see arch/arc/kernel/smp.c: ipi_send_msg_one()
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*/
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__mcip_cmd(CMD_INTRPT_READ_STATUS, cpu);
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ipi_was_pending = read_aux_reg(ARC_REG_MCIP_READBACK);
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if (!ipi_was_pending)
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__mcip_cmd(CMD_INTRPT_GENERATE_IRQ, cpu);
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raw_spin_unlock_irqrestore(&mcip_lock, flags);
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}
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static void mcip_ipi_clear(int irq)
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{
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unsigned int cpu, c;
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unsigned long flags;
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if (unlikely(irq == SOFTIRQ_IRQ)) {
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arc_softirq_clear(irq);
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return;
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}
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raw_spin_lock_irqsave(&mcip_lock, flags);
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/* Who sent the IPI */
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__mcip_cmd(CMD_INTRPT_CHECK_SOURCE, 0);
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cpu = read_aux_reg(ARC_REG_MCIP_READBACK); /* 1,2,4,8... */
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/*
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* In rare case, multiple concurrent IPIs sent to same target can
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* possibly be coalesced by MCIP into 1 asserted IRQ, so @cpus can be
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* "vectored" (multiple bits sets) as opposed to typical single bit
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*/
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do {
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c = __ffs(cpu); /* 0,1,2,3 */
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__mcip_cmd(CMD_INTRPT_GENERATE_ACK, c);
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cpu &= ~(1U << c);
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} while (cpu);
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raw_spin_unlock_irqrestore(&mcip_lock, flags);
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}
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static void mcip_probe_n_setup(void)
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{
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struct mcip_bcr mp;
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READ_BCR(ARC_REG_MCIP_BCR, mp);
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sprintf(smp_cpuinfo_buf,
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"Extn [SMP]\t: ARConnect (v%d): %d cores with %s%s%s%s%s\n",
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mp.ver, mp.num_cores,
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IS_AVAIL1(mp.ipi, "IPI "),
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IS_AVAIL1(mp.idu, "IDU "),
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IS_AVAIL1(mp.llm, "LLM "),
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IS_AVAIL1(mp.dbg, "DEBUG "),
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IS_AVAIL1(mp.gfrc, "GFRC"));
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cpuinfo_arc700[0].extn.gfrc = mp.gfrc;
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if (mp.dbg) {
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__mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, 0xf);
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__mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xf, 0xf);
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}
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}
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struct plat_smp_ops plat_smp_ops = {
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.info = smp_cpuinfo_buf,
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.init_early_smp = mcip_probe_n_setup,
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.init_per_cpu = mcip_setup_per_cpu,
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.ipi_send = mcip_ipi_send,
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.ipi_clear = mcip_ipi_clear,
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};
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#endif
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/***************************************************************************
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* ARCv2 Interrupt Distribution Unit (IDU)
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*
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* Connects external "COMMON" IRQs to core intc, providing:
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* -dynamic routing (IRQ affinity)
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* -load balancing (Round Robin interrupt distribution)
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* -1:N distribution
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*
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* It physically resides in the MCIP hw block
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*/
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#include <linux/irqchip.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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/*
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* Set the DEST for @cmn_irq to @cpu_mask (1 bit per core)
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*/
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static void idu_set_dest(unsigned int cmn_irq, unsigned int cpu_mask)
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{
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__mcip_cmd_data(CMD_IDU_SET_DEST, cmn_irq, cpu_mask);
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}
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static void idu_set_mode(unsigned int cmn_irq, unsigned int lvl,
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unsigned int distr)
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{
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union {
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unsigned int word;
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struct {
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unsigned int distr:2, pad:2, lvl:1, pad2:27;
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};
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} data;
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data.distr = distr;
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data.lvl = lvl;
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__mcip_cmd_data(CMD_IDU_SET_MODE, cmn_irq, data.word);
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}
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static void idu_irq_mask(struct irq_data *data)
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{
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unsigned long flags;
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raw_spin_lock_irqsave(&mcip_lock, flags);
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__mcip_cmd_data(CMD_IDU_SET_MASK, data->hwirq, 1);
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raw_spin_unlock_irqrestore(&mcip_lock, flags);
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}
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static void idu_irq_unmask(struct irq_data *data)
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{
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unsigned long flags;
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raw_spin_lock_irqsave(&mcip_lock, flags);
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__mcip_cmd_data(CMD_IDU_SET_MASK, data->hwirq, 0);
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raw_spin_unlock_irqrestore(&mcip_lock, flags);
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}
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#ifdef CONFIG_SMP
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static int
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idu_irq_set_affinity(struct irq_data *data, const struct cpumask *cpumask,
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bool force)
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{
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unsigned long flags;
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cpumask_t online;
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/* errout if no online cpu per @cpumask */
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if (!cpumask_and(&online, cpumask, cpu_online_mask))
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return -EINVAL;
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raw_spin_lock_irqsave(&mcip_lock, flags);
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idu_set_dest(data->hwirq, cpumask_bits(&online)[0]);
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idu_set_mode(data->hwirq, IDU_M_TRIG_LEVEL, IDU_M_DISTRI_RR);
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raw_spin_unlock_irqrestore(&mcip_lock, flags);
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return IRQ_SET_MASK_OK;
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}
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#endif
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static struct irq_chip idu_irq_chip = {
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.name = "MCIP IDU Intc",
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.irq_mask = idu_irq_mask,
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.irq_unmask = idu_irq_unmask,
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#ifdef CONFIG_SMP
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.irq_set_affinity = idu_irq_set_affinity,
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#endif
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};
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static int idu_first_irq;
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static void idu_cascade_isr(struct irq_desc *desc)
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{
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struct irq_domain *domain = irq_desc_get_handler_data(desc);
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unsigned int core_irq = irq_desc_get_irq(desc);
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unsigned int idu_irq;
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idu_irq = core_irq - idu_first_irq;
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generic_handle_irq(irq_find_mapping(domain, idu_irq));
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}
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static int idu_irq_map(struct irq_domain *d, unsigned int virq, irq_hw_number_t hwirq)
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{
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irq_set_chip_and_handler(virq, &idu_irq_chip, handle_level_irq);
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irq_set_status_flags(virq, IRQ_MOVE_PCNTXT);
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return 0;
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}
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static int idu_irq_xlate(struct irq_domain *d, struct device_node *n,
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const u32 *intspec, unsigned int intsize,
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irq_hw_number_t *out_hwirq, unsigned int *out_type)
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{
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irq_hw_number_t hwirq = *out_hwirq = intspec[0];
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int distri = intspec[1];
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unsigned long flags;
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*out_type = IRQ_TYPE_NONE;
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/* XXX: validate distribution scheme again online cpu mask */
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if (distri == 0) {
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/* 0 - Round Robin to all cpus, otherwise 1 bit per core */
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raw_spin_lock_irqsave(&mcip_lock, flags);
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idu_set_dest(hwirq, BIT(num_online_cpus()) - 1);
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idu_set_mode(hwirq, IDU_M_TRIG_LEVEL, IDU_M_DISTRI_RR);
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raw_spin_unlock_irqrestore(&mcip_lock, flags);
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} else {
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/*
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* DEST based distribution for Level Triggered intr can only
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* have 1 CPU, so generalize it to always contain 1 cpu
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*/
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int cpu = ffs(distri);
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if (cpu != fls(distri))
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pr_warn("IDU irq %lx distri mode set to cpu %x\n",
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hwirq, cpu);
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raw_spin_lock_irqsave(&mcip_lock, flags);
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idu_set_dest(hwirq, cpu);
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idu_set_mode(hwirq, IDU_M_TRIG_LEVEL, IDU_M_DISTRI_DEST);
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raw_spin_unlock_irqrestore(&mcip_lock, flags);
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}
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return 0;
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}
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static const struct irq_domain_ops idu_irq_ops = {
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.xlate = idu_irq_xlate,
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.map = idu_irq_map,
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};
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/*
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* [16, 23]: Statically assigned always private-per-core (Timers, WDT, IPI)
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* [24, 23+C]: If C > 0 then "C" common IRQs
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* [24+C, N]: Not statically assigned, private-per-core
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*/
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static int __init
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idu_of_init(struct device_node *intc, struct device_node *parent)
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{
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struct irq_domain *domain;
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/* Read IDU BCR to confirm nr_irqs */
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int nr_irqs = of_irq_count(intc);
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int i, irq;
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struct mcip_bcr mp;
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READ_BCR(ARC_REG_MCIP_BCR, mp);
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if (!mp.idu)
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panic("IDU not detected, but DeviceTree using it");
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pr_info("MCIP: IDU referenced from Devicetree %d irqs\n", nr_irqs);
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domain = irq_domain_add_linear(intc, nr_irqs, &idu_irq_ops, NULL);
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/* Parent interrupts (core-intc) are already mapped */
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for (i = 0; i < nr_irqs; i++) {
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/*
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* Return parent uplink IRQs (towards core intc) 24,25,.....
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* this step has been done before already
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* however we need it to get the parent virq and set IDU handler
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* as first level isr
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*/
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irq = irq_of_parse_and_map(intc, i);
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if (!i)
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idu_first_irq = irq;
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irq_set_chained_handler_and_data(irq, idu_cascade_isr, domain);
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}
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__mcip_cmd(CMD_IDU_ENABLE, 0);
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return 0;
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}
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IRQCHIP_DECLARE(arcv2_idu_intc, "snps,archs-idu-intc", idu_of_init);
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