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Diffstat (limited to 'arch/arc/kernel/mcip.c')
-rw-r--r--arch/arc/kernel/mcip.c55
1 files changed, 19 insertions, 36 deletions
diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c
index 30d806ce0..c41c364b9 100644
--- a/arch/arc/kernel/mcip.c
+++ b/arch/arc/kernel/mcip.c
@@ -15,6 +15,7 @@
#include <asm/mcip.h>
#include <asm/setup.h>
+#define IPI_IRQ 19
#define SOFTIRQ_IRQ 21
static char smp_cpuinfo_buf[128];
@@ -39,39 +40,26 @@ static void mcip_ipi_send(int cpu)
return;
}
+ raw_spin_lock_irqsave(&mcip_lock, flags);
+
/*
- * 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.
+ * 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);
- 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;
if (unlikely(irq == SOFTIRQ_IRQ)) {
arc_softirq_clear(irq);
@@ -83,7 +71,7 @@ static void mcip_ipi_clear(int irq)
/* Who sent the IPI */
__mcip_cmd(CMD_INTRPT_CHECK_SOURCE, 0);
- copy = cpu = read_aux_reg(ARC_REG_MCIP_READBACK); /* 1,2,4,8... */
+ cpu = read_aux_reg(ARC_REG_MCIP_READBACK); /* 1,2,4,8... */
/*
* In rare case, multiple concurrent IPIs sent to same target can
@@ -97,12 +85,6 @@ static void mcip_ipi_clear(int irq)
} 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
}
static void mcip_probe_n_setup(void)
@@ -111,13 +93,13 @@ static void mcip_probe_n_setup(void)
#ifdef CONFIG_CPU_BIG_ENDIAN
unsigned int pad3:8,
idu:1, llm:1, num_cores:6,
- iocoh:1, grtc:1, dbg:1, pad2:1,
+ iocoh:1, gfrc: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,
+ pad2:1, dbg:1, gfrc:1, iocoh:1,
num_cores:6, llm:1, idu:1,
pad3:8;
#endif
@@ -126,12 +108,13 @@ static void mcip_probe_n_setup(void)
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",
+ "Extn [SMP]\t: ARConnect (v%d): %d cores with %s%s%s%s%s\n",
mp.ver, mp.num_cores,
IS_AVAIL1(mp.ipi, "IPI "),
IS_AVAIL1(mp.idu, "IDU "),
+ IS_AVAIL1(mp.llm, "LLM "),
IS_AVAIL1(mp.dbg, "DEBUG "),
- IS_AVAIL1(mp.grtc, "GRTC"));
+ IS_AVAIL1(mp.gfrc, "GFRC"));
idu_detected = mp.idu;
@@ -140,8 +123,8 @@ static void mcip_probe_n_setup(void)
__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");
+ if (IS_ENABLED(CONFIG_ARC_HAS_GFRC) && !mp.gfrc)
+ panic("kernel trying to use non-existent GFRC\n");
}
struct plat_smp_ops plat_smp_ops = {