Commit 3ce0fefc authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARCv2: intc: untangle SMP, MCIP and IDU 



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: default avatarVineet Gupta <vgupta@synopsys.com>
parent 1001354c

arch/arc/Kconfig

+9 −8
Original line number Diff line number Diff line
@@ -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

arch/arc/include/asm/mcip.h

+16 −0
Original line number Diff line number Diff line
@@ -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

 *

arch/arc/kernel/mcip.c

+11 −20
Original line number Diff line number Diff line
@@ -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);
@@ -86,21 +87,7 @@ static void mcip_ipi_clear(int irq) 


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 +101,6 @@ 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 +116,8 @@ struct plat_smp_ops plat_smp_ops = { 
	.ipi_clear	= mcip_ipi_clear,

};



#endif



/***************************************************************************

 * ARCv2 Interrupt Distribution Unit (IDU)

 *
@@ -295,8 +283,11 @@ 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);

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