linux/arch/arc/kernel/mcip.c

313 lines
7.8 KiB
C

/*
* 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];
static void mcip_setup_per_cpu(int cpu)
{
smp_ipi_irq_setup(cpu, IPI_IRQ);
smp_ipi_irq_setup(cpu, SOFTIRQ_IRQ);
}
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;
if (mp.dbg) {
__mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, 0xf);
__mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xf, 0xf);
}
}
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);