Commit aca95fb6 authored by Paul Mackerras's avatar Paul Mackerras Committed by Madhavan Srinivasan
Browse files

powerpc/microwatt: Add SMP support 



This adds support for Microwatt systems with more than one core, and
updates the device tree for a 2-core version.

The secondary CPUs are started and sent to spin in __secondary_hold
very early on, in the platform probe function.  The reason for doing
this is so that they are there when smp_release_cpus() gets called,
which is before the platform init_smp function or even the platform
setup_arch function gets called.

Note that having two CPUs in the device tree doesn't preclude
operation with only one CPU.  The SYSCON_CPU_CTRL register has a
read-only field which indicates the number of CPU cores, so
microwatt_init_smp() will only start as many CPU cores as are present
in the system, and any extra CPU device-tree nodes will just be
ignored.

Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: default avatarMadhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/Z5xt8aooKyXZv6Kf@thinks.paulus.ozlabs.org
parent 3d45a3d0

arch/powerpc/boot/dts/microwatt.dts

+32 −2
Original line number Diff line number Diff line
@@ -142,6 +142,36 @@ PowerPC,Microwatt@0 { 
			ibm,mmu-lpid-bits = <12>;

			ibm,mmu-pid-bits = <20>;

		};



		PowerPC,Microwatt@1 {

			i-cache-sets = <2>;

			ibm,dec-bits = <64>;

			reservation-granule-size = <64>;

			clock-frequency = <100000000>;

			timebase-frequency = <100000000>;

			i-tlb-sets = <1>;

			ibm,ppc-interrupt-server#s = <1>;

			i-cache-block-size = <64>;

			d-cache-block-size = <64>;

			d-cache-sets = <2>;

			i-tlb-size = <64>;

			cpu-version = <0x990000>;

			status = "okay";

			i-cache-size = <0x1000>;

			ibm,processor-radix-AP-encodings = <0x0c 0xa0000010 0x20000015 0x4000001e>;

			tlb-size = <0>;

			tlb-sets = <0>;

			device_type = "cpu";

			d-tlb-size = <128>;

			d-tlb-sets = <2>;

			reg = <1>;

			general-purpose;

			64-bit;

			d-cache-size = <0x1000>;

			ibm,chip-id = <0>;

			ibm,mmu-lpid-bits = <12>;

			ibm,mmu-pid-bits = <20>;

		};

	};



	soc@c0000000 {
@@ -154,8 +184,8 @@ soc@c0000000 { 


		interrupt-controller@4000 {

			compatible = "openpower,xics-presentation", "ibm,ppc-xicp";

			ibm,interrupt-server-ranges = <0x0 0x1>;

			reg = <0x4000 0x100>;

			ibm,interrupt-server-ranges = <0x0 0x2>;

			reg = <0x4000 0x10 0x4010 0x10>;

		};



		ICS: interrupt-controller@5000 {

arch/powerpc/platforms/microwatt/Kconfig

+1 −1
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0

config PPC_MICROWATT

	depends on PPC_BOOK3S_64 && !SMP

	depends on PPC_BOOK3S_64

	bool "Microwatt SoC platform"

	select PPC_XICS

	select PPC_ICS_NATIVE

arch/powerpc/platforms/microwatt/Makefile

+1 −0
Original line number Diff line number Diff line 
obj-y	+= setup.o rng.o

obj-$(CONFIG_SMP) += smp.o

arch/powerpc/platforms/microwatt/microwatt.h

+1 −0
Original line number Diff line number Diff line
@@ -3,5 +3,6 @@ 
#define _MICROWATT_H



void microwatt_rng_init(void);

void microwatt_init_smp(void);



#endif /* _MICROWATT_H */

arch/powerpc/platforms/microwatt/setup.c

+9 −0
Original line number Diff line number Diff line
@@ -29,6 +29,14 @@ static int __init microwatt_populate(void) 
}

machine_arch_initcall(microwatt, microwatt_populate);



static int __init microwatt_probe(void)

{

	/* Main reason for having this is to start the other CPU(s) */

	if (IS_ENABLED(CONFIG_SMP))

		microwatt_init_smp();

	return 1;

}



static void __init microwatt_setup_arch(void)

{

	microwatt_rng_init();
@@ -45,6 +53,7 @@ static void microwatt_idle(void) 
define_machine(microwatt) {

	.name			= "microwatt",

	.compatible		= "microwatt-soc",

	.probe			= microwatt_probe,

	.init_IRQ		= microwatt_init_IRQ,

	.setup_arch		= microwatt_setup_arch,

	.progress		= udbg_progress,