Merge tag 'loongarch-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull initial Loongarch architecture code from Arnd Bergmann:
 "This is the majority of the loongarch architecture code, including the
  final system call interface and all core functionality.

  It still misses three sets of peripheral but vital patches to add
  support for other subsystems, which have yet to pass review:

   - The drivers/firmware/efi stub for booting from a standard UEFI
     firmware implementation. Both the original custom boot interface
     and a draft implementation of the EFI stub did not make it, so it
     is currently impossible to boot the kernel, until the loongarch
     specific portions get accepted into the UEFI subsystem

   - The drivers/irqchip/irq-loongson-*.c drivers are shared with the
     the MIPS port, but currently lack support for ACPI based booting,
     which will get merged through the irqchip subsystem.

   - Similarly, the drivers/pci/controller/pci-loongson.c needs to be
     modified for ACPI support, which will be merged through the PCI
     subsystem.

  While the port cannot actually be used before all the above are
  merged, having it in 5.19 helps to establish the user space ABI for
  the libc ports to build on, and to help any treewide changes in the
  mainline kernel get applied here as well.

  A gcc-12 based tool chains for build testing is now included in

    https://mirrors.edge.kernel.org/pub/tools/crosstool/"

Original description from Huacai Chen:
 "LoongArch is a new RISC ISA, which is a bit like MIPS or RISC-V.
  LoongArch includes a reduced 32-bit version (LA32R), a standard 32-bit
  version (LA32S) and a 64-bit version (LA64). LoongArch use ACPI as its
  boot protocol LoongArch-specific interrupt controllers (similar to APIC)
  are already added in the next revision of ACPI Specification (current
  revision is 6.4).

  This patchset is adding basic LoongArch support in mainline kernel, we
  can see a complete snapshot here:

    https://github.com/loongson/linux/tree/loongarch-next
    https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson.git/log/?h=loongarch-next

  Cross-compile tool chain to build kernel:

    https://github.com/loongson/build-tools/releases/download/2021.12.21/loongarch64-clfs-2022-03-03-cross-tools-gcc-glibc.tar.xz

  A CLFS-based Linux distro:

    https://github.com/loongson/build-tools/releases/download/2021.12.21/loongarch64-clfs-system-2022-03-03.tar.bz2

  Open-source tool chain which is under review (Binutils and Gcc are already upstream):

    https://github.com/loongson/binutils-gdb/tree/upstream_v3.1
    https://github.com/loongson/gcc/tree/loongarch_upstream_v6.3
    https://github.com/loongson/glibc/tree/loongarch_2_35_dev_v2.2

  Loongson and LoongArch documentations:

    https://github.com/loongson/LoongArch-Documentation

  LoongArch-specific interrupt controllers:

    https://mantis.uefi.org/mantis/view.php?id=2203
    https://mantis.uefi.org/mantis/view.php?id=2313"

Link: https://lore.kernel.org/lkml/20220603072053.35005-1-chenhuacai@loongson.cn/

* tag 'loongarch-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (24 commits)
  MAINTAINERS: Add maintainer information for LoongArch
  LoongArch: Add Loongson-3 default config file
  LoongArch: Add Non-Uniform Memory Access (NUMA) support
  LoongArch: Add multi-processor (SMP) support
  LoongArch: Add VDSO and VSYSCALL support
  LoongArch: Add some library functions
  LoongArch: Add misc common routines
  LoongArch: Add ELF and module support
  LoongArch: Add signal handling support
  LoongArch: Add system call support
  LoongArch: Add memory management
  LoongArch: Add process management
  LoongArch: Add exception/interrupt handling
  LoongArch: Add boot and setup routines
  LoongArch: Add other common headers
  LoongArch: Add atomic/locking headers
  LoongArch: Add CPU definition headers
  LoongArch: Add build infrastructure
  LoongArch: Add writecombine support for drm
  LoongArch: Add ELF-related definitions
  ...

1 files changed, 102 insertions, 0 deletions

diff --git a/arch/loongarch/kernel/reset.c b/arch/loongarch/kernel/reset.c
new file mode 100644
index 000000000000..2b86469e4718
--- /dev/null
+++ b/arch/loongarch/kernel/reset.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <linux/kernel.h>
+#include <linux/acpi.h>
+#include <linux/efi.h>
+#include <linux/export.h>
+#include <linux/pm.h>
+#include <linux/types.h>
+#include <linux/reboot.h>
+#include <linux/delay.h>
+#include <linux/console.h>
+
+#include <acpi/reboot.h>
+#include <asm/compiler.h>
+#include <asm/idle.h>
+#include <asm/loongarch.h>
+#include <asm/reboot.h>
+
+static void default_halt(void)
+{
+	local_irq_disable();
+	clear_csr_ecfg(ECFG0_IM);
+
+	pr_notice("\n\n** You can safely turn off the power now **\n\n");
+	console_flush_on_panic(CONSOLE_FLUSH_PENDING);
+
+	while (true) {
+		__arch_cpu_idle();
+	}
+}
+
+static void default_poweroff(void)
+{
+#ifdef CONFIG_EFI
+	efi.reset_system(EFI_RESET_SHUTDOWN, EFI_SUCCESS, 0, NULL);
+#endif
+	while (true) {
+		__arch_cpu_idle();
+	}
+}
+
+static void default_restart(void)
+{
+#ifdef CONFIG_EFI
+	if (efi_capsule_pending(NULL))
+		efi_reboot(REBOOT_WARM, NULL);
+	else
+		efi_reboot(REBOOT_COLD, NULL);
+#endif
+	if (!acpi_disabled)
+		acpi_reboot();
+
+	while (true) {
+		__arch_cpu_idle();
+	}
+}
+
+void (*pm_restart)(void);
+EXPORT_SYMBOL(pm_restart);
+
+void (*pm_power_off)(void);
+EXPORT_SYMBOL(pm_power_off);
+
+void machine_halt(void)
+{
+#ifdef CONFIG_SMP
+	preempt_disable();
+	smp_send_stop();
+#endif
+	default_halt();
+}
+
+void machine_power_off(void)
+{
+#ifdef CONFIG_SMP
+	preempt_disable();
+	smp_send_stop();
+#endif
+	pm_power_off();
+}
+
+void machine_restart(char *command)
+{
+#ifdef CONFIG_SMP
+	preempt_disable();
+	smp_send_stop();
+#endif
+	do_kernel_restart(command);
+	pm_restart();
+}
+
+static int __init loongarch_reboot_setup(void)
+{
+	pm_restart = default_restart;
+	pm_power_off = default_poweroff;
+
+	return 0;
+}
+
+arch_initcall(loongarch_reboot_setup);