Re: [PATCH v2 1/9] powerpc: Add Microwatt platform
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2021-06-19 03:04:14
Excerpts from Paul Mackerras's message of June 18, 2021 1:43 pm:
Microwatt is a FPGA-based implementation of the Power ISA. It currently only implements little-endian 64-bit mode, and does not (yet) support SMP, VMX, VSX or transactional memory. It has an optional FPU, and an optional MMU (required for running Linux, obviously) which implements a configurable radix tree but not hypervisor mode or nested radix translation. This adds a new machine type to support FPGA-based SoCs with a Microwatt core. CONFIG_MATH_EMULATION can be selected for Microwatt SOCs which don't have the FPU.
The only thing I can think of is you may want to select PPC_RADIX and other possible things that are required, but that's not a big deal at the moment. I have a few kernel size reduction config patches (like CONFIG_PPC_HASH) I might be able to upstream now for Microwatt, so I could do a bit of a pass over the Kconfig stuff at that point. Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
quoted hunk ↗ jump to hunk
Signed-off-by: Paul Mackerras <redacted> --- arch/powerpc/Kconfig | 2 +- arch/powerpc/platforms/Kconfig | 1 + arch/powerpc/platforms/Makefile | 1 + arch/powerpc/platforms/microwatt/Kconfig | 9 +++++++++ arch/powerpc/platforms/microwatt/Makefile | 1 + arch/powerpc/platforms/microwatt/setup.c | 23 +++++++++++++++++++++++ 6 files changed, 36 insertions(+), 1 deletion(-) create mode 100644 arch/powerpc/platforms/microwatt/Kconfig create mode 100644 arch/powerpc/platforms/microwatt/Makefile create mode 100644 arch/powerpc/platforms/microwatt/setup.cdiff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 386ae12d8523..5ce51c38a346 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig@@ -422,7 +422,7 @@ config HUGETLB_PAGE_SIZE_VARIABLE config MATH_EMULATION bool "Math emulation" - depends on 4xx || PPC_8xx || PPC_MPC832x || BOOKE + depends on 4xx || PPC_8xx || PPC_MPC832x || BOOKE || PPC_MICROWATT select PPC_FPU_REGS help Some PowerPC chips designed for embedded applications do not havediff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig index 7a5e8f4541e3..74be4d06afbf 100644 --- a/arch/powerpc/platforms/Kconfig +++ b/arch/powerpc/platforms/Kconfig@@ -20,6 +20,7 @@ source "arch/powerpc/platforms/embedded6xx/Kconfig" source "arch/powerpc/platforms/44x/Kconfig" source "arch/powerpc/platforms/40x/Kconfig" source "arch/powerpc/platforms/amigaone/Kconfig" +source "arch/powerpc/platforms/microwatt/Kconfig" config KVM_GUEST bool "KVM Guest support"diff --git a/arch/powerpc/platforms/Makefile b/arch/powerpc/platforms/Makefile index 143d4417f6cc..edcb54cdb1a8 100644 --- a/arch/powerpc/platforms/Makefile +++ b/arch/powerpc/platforms/Makefile@@ -22,3 +22,4 @@ obj-$(CONFIG_PPC_CELL) += cell/ obj-$(CONFIG_PPC_PS3) += ps3/ obj-$(CONFIG_EMBEDDED6xx) += embedded6xx/ obj-$(CONFIG_AMIGAONE) += amigaone/ +obj-$(CONFIG_PPC_MICROWATT) += microwatt/diff --git a/arch/powerpc/platforms/microwatt/Kconfig b/arch/powerpc/platforms/microwatt/Kconfig new file mode 100644 index 000000000000..3be01e78ce57 --- /dev/null +++ b/arch/powerpc/platforms/microwatt/Kconfig@@ -0,0 +1,9 @@ +# SPDX-License-Identifier: GPL-2.0 +config PPC_MICROWATT + depends on PPC_BOOK3S_64 && !SMP + bool "Microwatt SoC platform" + select PPC_XICS + select PPC_NATIVE + help + This option enables support for FPGA-based Microwatt implementations. +diff --git a/arch/powerpc/platforms/microwatt/Makefile b/arch/powerpc/platforms/microwatt/Makefile new file mode 100644 index 000000000000..e6885b3b2ee7 --- /dev/null +++ b/arch/powerpc/platforms/microwatt/Makefile@@ -0,0 +1 @@ +obj-y += setup.odiff --git a/arch/powerpc/platforms/microwatt/setup.c b/arch/powerpc/platforms/microwatt/setup.c new file mode 100644 index 000000000000..d80d52612672 --- /dev/null +++ b/arch/powerpc/platforms/microwatt/setup.c@@ -0,0 +1,23 @@ +/* + * Microwatt FPGA-based SoC platform setup code. + * + * Copyright 2020 Paul Mackerras (paulus@ozlabs.org), IBM Corp. + */ + +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/stddef.h> +#include <linux/init.h> +#include <asm/machdep.h> +#include <asm/time.h> + +static int __init microwatt_probe(void) +{ + return of_machine_is_compatible("microwatt-soc"); +} + +define_machine(microwatt) { + .name = "microwatt", + .probe = microwatt_probe, + .calibrate_decr = generic_calibrate_decr, +};-- 2.31.1