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 at synopsys.com>
---
arch/arc/Kconfig | 17 +++++++++--------
arch/arc/include/asm/mcip.h | 16 ++++++++++++++++
arch/arc/kernel/mcip.c | 32 ++++++++++++--------------------
3 files changed, 37 insertions(+), 28 deletions(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index df8c8864b5ba..7b65d0e18fa0 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -186,14 +186,6 @@ if SMP
config ARC_HAS_COH_CACHES
def_bool n
-config ARC_MCIP
- bool "ARConnect Multicore IP (MCIP) Support "
- depends on ISA_ARCV2
- help
- This IP block enables SMP in ARC-HS38 cores.
- It provides for cross-core interrupts, multi-core debug
- hardware semaphores, shared memory,....
-
config NR_CPUS
int "Maximum number of CPUs (2-4096)"
range 2 4096
@@ -211,6 +203,15 @@ config ARC_SMP_HALT_ON_RESET
endif #SMP
+config ARC_MCIP
+ bool "ARConnect Multicore IP (MCIP) Support "
+ depends on ISA_ARCV2
+ default y if SMP
+ help
+ This IP block enables SMP in ARC-HS38 cores.
+ It provides for cross-core interrupts, multi-core debug
+ hardware semaphores, shared memory,....
+
menuconfig ARC_CACHE
bool "Enable Cache Support"
default y
diff --git a/arch/arc/include/asm/mcip.h b/arch/arc/include/asm/mcip.h
index 847e3bbe387f..c8fbe4114bad 100644
--- a/arch/arc/include/asm/mcip.h
+++ b/arch/arc/include/asm/mcip.h
@@ -55,6 +55,22 @@ struct mcip_cmd {
#define IDU_M_DISTRI_DEST 0x2
};
+struct mcip_bcr {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ unsigned int pad3:8,
+ idu:1, llm:1, num_cores:6,
+ 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, gfrc:1, iocoh:1,
+ num_cores:6, llm:1, idu:1,
+ pad3:8;
+#endif
+};
+
/*
* MCIP programming model
*
diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c
index 72f9179b1a24..423d7113e664 100644
--- a/arch/arc/kernel/mcip.c
+++ b/arch/arc/kernel/mcip.c
@@ -15,11 +15,12 @@
#include <asm/mcip.h>
#include <asm/setup.h>
-static char smp_cpuinfo_buf[128];
-static int idu_detected;
-
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);
@@ -84,23 +85,10 @@ static void mcip_ipi_clear(int irq)
raw_spin_unlock_irqrestore(&mcip_lock, flags);
}
+
static void mcip_probe_n_setup(void)
{
- struct mcip_bcr {
-#ifdef CONFIG_CPU_BIG_ENDIAN
- unsigned int pad3:8,
- idu:1, llm:1, num_cores:6,
- 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, gfrc:1, iocoh:1,
- num_cores:6, llm:1, idu:1,
- pad3:8;
-#endif
- } mp;
+ struct mcip_bcr mp;
READ_BCR(ARC_REG_MCIP_BCR, mp);
@@ -114,7 +102,6 @@ static void mcip_probe_n_setup(void)
IS_AVAIL1(mp.gfrc, "GFRC"));
cpuinfo_arc700[0].extn.gfrc = mp.gfrc;
- idu_detected = mp.idu;
if (mp.dbg) {
__mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, 0xf);
@@ -130,6 +117,8 @@ struct plat_smp_ops plat_smp_ops = {
.ipi_clear = mcip_ipi_clear,
};
+#endif
+
/***************************************************************************
* ARCv2 Interrupt Distribution Unit (IDU)
*
@@ -295,8 +284,11 @@ idu_of_init(struct device_node *intc, struct device_node *parent)
/* Read IDU BCR to confirm nr_irqs */
int nr_irqs = of_irq_count(intc);
int i, irq;
+ struct mcip_bcr mp;
+
+ READ_BCR(ARC_REG_MCIP_BCR, mp);
- if (!idu_detected)
+ if (!mp.idu)
panic("IDU not detected, but DeviceTree using it");
pr_info("MCIP: IDU referenced from Devicetree %d irqs\n", nr_irqs);
--
2.7.4
