Thanks Marek, On 3/25/2026 6:43 AM, Marek Vasut wrote: > Add configuration for ARMv8-M aarch32 core, which are currently > Cortex-M23/M33 cores. These cores are treated similar to ARMv7-M > cores, except the code has to be compiled with matching compiler > -march=armv8-m.main flag . These cores have no MMU, they have MPU, > which is currently not configured. > > Unlike ARMv7-M, these cores have 512 interrupt vectors. While the > SYS_ARM_ARCH should be set to 8, it is set to 7 because all of the > initialization code is built from from arch/arm/cpu/armv7m and not > armv8. Furthermore, CONFIG_ARM64 must be disabled, although DTs > for devices using these cores do come from arch/arm64/boot/dts . > > To avoid excess duplication in Makefiles, introduce one new Kconfig > symbol, CPU_V78M. The CPU_V78M cover both ARMv7-M and ARMv8-M cores. > > Signed-off-by: Marek Vasut <[email protected]> > --- > Cc: Casey Connolly <[email protected]> > Cc: Heinrich Schuchardt <[email protected]> > Cc: Ilias Apalodimas <[email protected]> > Cc: Jerome Forissier <[email protected]> <[email protected]> > Cc: Tom Rini <[email protected]> > Cc: [email protected] > --- > Makefile | 8 ++++++-- > arch/arm/Kconfig | 18 +++++++++++++++--- [..]> > +config CPU_V8M > + bool > + select CPU_V78M > + select SYS_CACHE_SHIFT_6
referring to M55 TRM [0], (which seems to be next processor in this family) page- (68-69) CCSIDR, LTM cache size is not default to 64. my suggestion will be to keep cache line same as of V7M, unless you think otherwise. > + > config SYS_CPU > default "arm720t" if CPU_ARM720T > default "arm920t" if CPU_ARM920T > @@ -389,6 +399,7 @@ config SYS_CPU > default "armv7" if CPU_V7A > default "armv7" if CPU_V7R > default "armv7m" if CPU_V7M > + default "armv7m" if CPU_V8M > default "armv8" if ARM64 > > config SYS_ARM_ARCH > @@ -402,6 +413,7 @@ config SYS_ARM_ARCH > default 7 if CPU_V7A > default 7 if CPU_V7M > default 7 if CPU_V7R > + default 7 if CPU_V8M > default 8 if ARM64 > > choice > @@ -445,7 +457,7 @@ config ARCH_CPU_INIT > > config SYS_ARCH_TIMER > bool "ARM Generic Timer support" > - depends on CPU_V7A || CPU_V7M || ARM64 > + depends on CPU_V7A || CPU_V78M || ARM64 > default y if ARM64 > help > The ARM Generic Timer (aka arch-timer) provides an architected > diff --git a/arch/arm/Makefile b/arch/arm/Makefile > index b36b0742580..de975fc9368 100644 > --- a/arch/arm/Makefile > +++ b/arch/arm/Makefile > @@ -16,6 +16,7 @@ arch-$(CONFIG_CPU_V7A) =$(call cc-option, > -march=armv7-a, \ > $(call cc-option, -march=armv7)) > arch-$(CONFIG_CPU_V7M) =-march=armv7-m > arch-$(CONFIG_CPU_V7R) =-march=armv7-r > +arch-$(CONFIG_CPU_V8M) =-march=armv8-m.main > ifeq ($(CONFIG_ARM64_CRC32),y) > arch-$(CONFIG_ARM64) =-march=armv8-a+crc > else > @@ -42,6 +43,7 @@ tune-$(CONFIG_CPU_ARM1136) = > tune-$(CONFIG_CPU_ARM1176) = > tune-$(CONFIG_CPU_V7A) =-mtune=generic-armv7-a > tune-$(CONFIG_CPU_V7R) = > +tune-$(CONFIG_CPU_V8M) = > tune-$(CONFIG_ARM64) = > > # Evaluate tune cc-option calls now > diff --git a/arch/arm/cpu/armv7m/Makefile b/arch/arm/cpu/armv7m/Makefile > index baeac9343d9..33d49dc3d35 100644 > --- a/arch/arm/cpu/armv7m/Makefile > +++ b/arch/arm/cpu/armv7m/Makefile > @@ -4,6 +4,7 @@ > # Wolfgang Denk, DENX Software Engineering, [email protected]. > > extra-y := start.o > -obj-y += cpu.o cache.o > +obj-y += cache.o > +obj-$(CONFIG_CPU_V7M) += cpu.o Why you are dropping cpu.c compilation > obj-$(CONFIG_SYS_ARM_MPU) += mpu.o > obj-$(CONFIG_SYS_ARCH_TIMER) += systick-timer.o > diff --git a/arch/arm/include/asm/armv7_mpu.h > b/arch/arm/include/asm/armv7_mpu.h > index 16b9d0d1aeb..b615b1bc9dc 100644 > --- a/arch/arm/include/asm/armv7_mpu.h > +++ b/arch/arm/include/asm/armv7_mpu.h > @@ -11,7 +11,7 @@ [..] [0] https://documentation-service.arm.com/static/6622c173fabc8c11c7b53a92?token=
