swh:1:snp:77163734605b0ec556b01d897b7bb4a7e30d46b6
Tip revision: 64291f7db5bd8150a74ad2036f1037e6a0428df2 authored by Linus Torvalds on 30 August 2015, 18:34:09 UTC
Linux 4.2
Linux 4.2
Tip revision: 64291f7
mcip.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/spinlock.h>
#include <asm/mcip.h>
static char smp_cpuinfo_buf[128];
static int idu_detected;
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;
int ipi_was_pending;
/*
* NOTE: We must spin here if the other cpu hasn't yet
* serviced a previous message. This can burn lots
* of time, but we MUST follows this protocol or
* ipi messages can be lost!!!
* Also, we must release the lock in this loop because
* the other side may get to this same loop and not
* be able to ack -- thus causing deadlock.
*/
do {
raw_spin_lock_irqsave(&mcip_lock, flags);
__mcip_cmd(CMD_INTRPT_READ_STATUS, cpu);
ipi_was_pending = read_aux_reg(ARC_REG_MCIP_READBACK);
if (ipi_was_pending == 0)
break; /* break out but keep lock */
raw_spin_unlock_irqrestore(&mcip_lock, flags);
} while (1);
__mcip_cmd(CMD_INTRPT_GENERATE_IRQ, cpu);
raw_spin_unlock_irqrestore(&mcip_lock, flags);
#ifdef CONFIG_ARC_IPI_DBG
if (ipi_was_pending)
pr_info("IPI ACK delayed from cpu %d\n", cpu);
#endif
}
static void mcip_ipi_clear(int irq)
{
unsigned int cpu, c;
unsigned long flags;
unsigned int __maybe_unused copy;
raw_spin_lock_irqsave(&mcip_lock, flags);
/* Who sent the IPI */
__mcip_cmd(CMD_INTRPT_CHECK_SOURCE, 0);
copy = 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);
#ifdef CONFIG_ARC_IPI_DBG
if (c != __ffs(copy))
pr_info("IPIs from %x coalesced to %x\n",
copy, raw_smp_processor_id());
#endif
}
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"));
idu_detected = mp.idu;
if (mp.dbg) {
__mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, 0xf);
__mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xf, 0xf);
}
if (IS_ENABLED(CONFIG_ARC_HAS_GRTC) && !mp.grtc)
panic("kernel trying to use non-existent GRTC\n");
}
/***************************************************************************
* 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(struct irq_data *data)
{
unsigned long flags;
raw_spin_lock_irqsave(&mcip_lock, flags);
__mcip_cmd_data(CMD_IDU_SET_MASK, data->hwirq, 1);
raw_spin_unlock_irqrestore(&mcip_lock, flags);
}
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);
}
#ifdef CONFIG_SMP
static int
idu_irq_set_affinity(struct irq_data *data, const struct cpumask *cpumask,
bool force)
{
unsigned long flags;
cpumask_t online;
/* errout if no online cpu per @cpumask */
if (!cpumask_and(&online, cpumask, cpu_online_mask))
return -EINVAL;
raw_spin_lock_irqsave(&mcip_lock, flags);
idu_set_dest(data->hwirq, cpumask_bits(&online)[0]);
idu_set_mode(data->hwirq, IDU_M_TRIG_LEVEL, IDU_M_DISTRI_RR);
raw_spin_unlock_irqrestore(&mcip_lock, flags);
return IRQ_SET_MASK_OK;
}
#endif
static struct irq_chip idu_irq_chip = {
.name = "MCIP IDU Intc",
.irq_mask = idu_irq_mask,
.irq_unmask = idu_irq_unmask,
#ifdef CONFIG_SMP
.irq_set_affinity = idu_irq_set_affinity,
#endif
};
static int idu_first_irq;
static void idu_cascade_isr(unsigned int core_irq, struct irq_desc *desc)
{
struct irq_domain *domain = irq_desc_get_handler_data(desc);
unsigned int idu_irq;
idu_irq = core_irq - idu_first_irq;
generic_handle_irq(irq_find_mapping(domain, idu_irq));
}
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 int idu_irq_xlate(struct irq_domain *d, struct device_node *n,
const u32 *intspec, unsigned int intsize,
irq_hw_number_t *out_hwirq, unsigned int *out_type)
{
irq_hw_number_t hwirq = *out_hwirq = intspec[0];
int distri = intspec[1];
unsigned long flags;
*out_type = IRQ_TYPE_NONE;
/* XXX: validate distribution scheme again online cpu mask */
if (distri == 0) {
/* 0 - Round Robin to all cpus, otherwise 1 bit per core */
raw_spin_lock_irqsave(&mcip_lock, flags);
idu_set_dest(hwirq, BIT(num_online_cpus()) - 1);
idu_set_mode(hwirq, IDU_M_TRIG_LEVEL, IDU_M_DISTRI_RR);
raw_spin_unlock_irqrestore(&mcip_lock, flags);
} else {
/*
* DEST based distribution for Level Triggered intr can only
* have 1 CPU, so generalize it to always contain 1 cpu
*/
int cpu = ffs(distri);
if (cpu != fls(distri))
pr_warn("IDU irq %lx distri mode set to cpu %x\n",
hwirq, cpu);
raw_spin_lock_irqsave(&mcip_lock, flags);
idu_set_dest(hwirq, cpu);
idu_set_mode(hwirq, IDU_M_TRIG_LEVEL, IDU_M_DISTRI_DEST);
raw_spin_unlock_irqrestore(&mcip_lock, flags);
}
return 0;
}
static const struct irq_domain_ops idu_irq_ops = {
.xlate = idu_irq_xlate,
.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;
/* Read IDU BCR to confirm nr_irqs */
int nr_irqs = of_irq_count(intc);
int i, irq;
if (!idu_detected)
panic("IDU not detected, but DeviceTree using it");
pr_info("MCIP: IDU referenced from Devicetree %d 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++) {
/*
* 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
*/
irq = irq_of_parse_and_map(intc, i);
if (!i)
idu_first_irq = irq;
irq_set_chained_handler_and_data(irq, idu_cascade_isr, domain);
}
__mcip_cmd(CMD_IDU_ENABLE, 0);
return 0;
}
IRQCHIP_DECLARE(arcv2_idu_intc, "snps,archs-idu-intc", idu_of_init);