diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-19 09:56:38 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-19 09:56:38 -0700 |
commit | 1009aa1205c2c5e9101437dcadfa195708d863bf (patch) | |
tree | 49e76c84522866fae25ba37372aef241b8713c3f | |
parent | 1d0926e99de7b486321e3db924b445531eea5e18 (diff) | |
parent | 627672cf431b0379c07cc8d146f907cda6797222 (diff) |
Merge tag 'riscv-for-linus-4.19-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux
Pull RISC-V updates from Palmer Dabbelt:
"This contains some major improvements to the RISC-V port, including
the necessary interrupt controller and timer support to actually make
it to userspace. Support for three devices has been added:
- the ISA-mandated timers on RISC-V systems.
- the ISA-mandated first-level interrupt controller on RISC-V
systems, which is handled as part of our core arch code because
it's very small and tightly tied to the ISA.
- SiFive's platform-level interrupt controller, which talks to the
actual devices.
In addition to these new devices, there are a handful of cleanups all
over the RISC-V tree:
- build fixes for various configurations:
* A fix to the vDSO build's makefile so it respects CFLAGS.
* The addition of __lshrti3, a libgcc derived function necessary
for some 32-bit configurations.
* !SMP && PERF_EVENTS
- Cleanups to the arch code to remove the remnants of old versions of
the drivers that were just properly submitted.
* Some dead code from the timer driver, most of which wasn't ever
even compiled.
* Cleanups of some interrupt #defines, which are now local to the
interrupt handling code.
- Fixes to ptrace(), which while not being sufficient to fully make
GDB work are at least sufficient to get simple GDB tasks to work.
- Early printk support via RISC-V's architecturally mandated SBI
console device.
- A fix to our early debug trap handler to ensure it's always
aligned.
These patches have all been through a fairly extensive review process,
but as this enables a whole pile of functionality (ie, userspace) I'm
confident we'll need to submit a few more patches. The only concrete
issues I know about are the sys_riscv_flush_icache patches, but as I
managed to screw those up on Friday I figured it'd be best to let them
bake another week.
This tag boots a Fedora root filesystem on QEMU's master branch for
me, and before this morning's rebase (from 4.18-rc8 to 4.18) it booted
on the HiFive Unleashed.
Thanks to Christoph Hellwig and the other guys at WD for getting the
new drivers in shape!"
* tag 'riscv-for-linus-4.19-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux:
dt-bindings: interrupt-controller: SiFive Plaform Level Interrupt Controller
dt-bindings: interrupt-controller: RISC-V local interrupt controller
RISC-V: Fix !CONFIG_SMP compilation error
irqchip: add a SiFive PLIC driver
RISC-V: Add the directive for alignment of stvec's value
clocksource: new RISC-V SBI timer driver
RISC-V: implement low-level interrupt handling
RISC-V: add a definition for the SIE SEIE bit
RISC-V: remove INTERRUPT_CAUSE_* defines from asm/irq.h
RISC-V: simplify software interrupt / IPI code
RISC-V: remove timer leftovers
RISC-V: Add early printk support via the SBI console
RISC-V: Don't increment sepc after breakpoint.
RISC-V: implement __lshrti3.
RISC-V: Use KBUILD_CFLAGS instead of KCFLAGS when building the vDSO
27 files changed, 625 insertions, 59 deletions
diff --git a/Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt b/Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt new file mode 100644 index 000000000000..b0a8af51c388 --- /dev/null +++ b/Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt @@ -0,0 +1,44 @@ +RISC-V Hart-Level Interrupt Controller (HLIC) +--------------------------------------------- + +RISC-V cores include Control Status Registers (CSRs) which are local to each +CPU core (HART in RISC-V terminology) and can be read or written by software. +Some of these CSRs are used to control local interrupts connected to the core. +Every interrupt is ultimately routed through a hart's HLIC before it +interrupts that hart. + +The RISC-V supervisor ISA manual specifies three interrupt sources that are +attached to every HLIC: software interrupts, the timer interrupt, and external +interrupts. Software interrupts are used to send IPIs between cores. The +timer interrupt comes from an architecturally mandated real-time timer that is +controller via Supervisor Binary Interface (SBI) calls and CSR reads. External +interrupts connect all other device interrupts to the HLIC, which are routed +via the platform-level interrupt controller (PLIC). + +All RISC-V systems that conform to the supervisor ISA specification are +required to have a HLIC with these three interrupt sources present. Since the +interrupt map is defined by the ISA it's not listed in the HLIC's device tree +entry, though external interrupt controllers (like the PLIC, for example) will +need to define how their interrupts map to the relevant HLICs. This means +a PLIC interrupt property will typically list the HLICs for all present HARTs +in the system. + +Required properties: +- compatible : "riscv,cpu-intc" +- #interrupt-cells : should be <1> +- interrupt-controller : Identifies the node as an interrupt controller + +Furthermore, this interrupt-controller MUST be embedded inside the cpu +definition of the hart whose CSRs control these local interrupts. + +An example device tree entry for a HLIC is show below. + + cpu1: cpu@1 { + compatible = "riscv"; + ... + cpu1-intc: interrupt-controller { + #interrupt-cells = <1>; + compatible = "riscv,cpu-intc", "sifive,fu540-c000-cpu-intc"; + interrupt-controller; + }; + }; diff --git a/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.txt b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.txt new file mode 100644 index 000000000000..6adf7a6e8825 --- /dev/null +++ b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.txt @@ -0,0 +1,58 @@ +SiFive Platform-Level Interrupt Controller (PLIC) +------------------------------------------------- + +SiFive SOCs include an implementation of the Platform-Level Interrupt Controller +(PLIC) high-level specification in the RISC-V Privileged Architecture +specification. The PLIC connects all external interrupts in the system to all +hart contexts in the system, via the external interrupt source in each hart. + +A hart context is a privilege mode in a hardware execution thread. For example, +in an 4 core system with 2-way SMT, you have 8 harts and probably at least two +privilege modes per hart; machine mode and supervisor mode. + +Each interrupt can be enabled on per-context basis. Any context can claim +a pending enabled interrupt and then release it once it has been handled. + +Each interrupt has a configurable priority. Higher priority interrupts are +serviced first. Each context can specify a priority threshold. Interrupts +with priority below this threshold will not cause the PLIC to raise its +interrupt line leading to the context. + +While the PLIC supports both edge-triggered and level-triggered interrupts, +interrupt handlers are oblivious to this distinction and therefore it is not +specified in the PLIC device-tree binding. + +While the RISC-V ISA doesn't specify a memory layout for the PLIC, the +"sifive,plic-1.0.0" device is a concrete implementation of the PLIC that +contains a specific memory layout, which is documented in chapter 8 of the +SiFive U5 Coreplex Series Manual <https://static.dev.sifive.com/U54-MC-RVCoreIP.pdf>. + +Required properties: +- compatible : "sifive,plic-1.0.0" and a string identifying the actual + detailed implementation in case that specific bugs need to be worked around. +- #address-cells : should be <0> or more. +- #interrupt-cells : should be <1> or more. +- interrupt-controller : Identifies the node as an interrupt controller. +- reg : Should contain 1 register range (address and length). +- interrupts-extended : Specifies which contexts are connected to the PLIC, + with "-1" specifying that a context is not present. Each node pointed + to should be a riscv,cpu-intc node, which has a riscv node as parent. +- riscv,ndev: Specifies how many external interrupts are supported by + this controller. + +Example: + + plic: interrupt-controller@c000000 { + #address-cells = <0>; + #interrupt-cells = <1>; + compatible = "sifive,plic-1.0.0", "sifive,fu540-c000-plic"; + interrupt-controller; + interrupts-extended = < + &cpu0-intc 11 + &cpu1-intc 11 &cpu1-intc 9 + &cpu2-intc 11 &cpu2-intc 9 + &cpu3-intc 11 &cpu3-intc 9 + &cpu4-intc 11 &cpu4-intc 9>; + reg = <0xc000000 0x4000000>; + riscv,ndev = <10>; + }; diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index 2627e4813edf..9ddd88bb30b7 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -25,6 +25,9 @@ ifeq ($(CONFIG_ARCH_RV64I),y) KBUILD_CFLAGS += -mabi=lp64 KBUILD_AFLAGS += -mabi=lp64 + + KBUILD_CFLAGS += $(call cc-ifversion, -ge, 0500, -DCONFIG_ARCH_SUPPORTS_INT128) + KBUILD_MARCH = rv64im LDFLAGS += -melf64lriscv else diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig index 07326466871b..36473d7dbaac 100644 --- a/arch/riscv/configs/defconfig +++ b/arch/riscv/configs/defconfig @@ -76,3 +76,4 @@ CONFIG_ROOT_NFS=y CONFIG_CRYPTO_USER_API_HASH=y CONFIG_MODULES=y CONFIG_MODULE_UNLOAD=y +CONFIG_SIFIVE_PLIC=y diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h index 421fa3585798..28a0d1cb374c 100644 --- a/arch/riscv/include/asm/csr.h +++ b/arch/riscv/include/asm/csr.h @@ -54,6 +54,7 @@ /* Interrupt Enable and Interrupt Pending flags */ #define SIE_SSIE _AC(0x00000002, UL) /* Software Interrupt Enable */ #define SIE_STIE _AC(0x00000020, UL) /* Timer Interrupt Enable */ +#define SIE_SEIE _AC(0x00000200, UL) /* External Interrupt Enable */ #define EXC_INST_MISALIGNED 0 #define EXC_INST_ACCESS 1 diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h index 4dee9d4c13c0..996b6fbe17a6 100644 --- a/arch/riscv/include/asm/irq.h +++ b/arch/riscv/include/asm/irq.h @@ -17,11 +17,8 @@ #define NR_IRQS 0 -#define INTERRUPT_CAUSE_SOFTWARE 1 -#define INTERRUPT_CAUSE_TIMER 5 -#define INTERRUPT_CAUSE_EXTERNAL 9 - void riscv_timer_interrupt(void); +void riscv_software_interrupt(void); #include <asm-generic/irq.h> diff --git a/arch/riscv/include/asm/perf_event.h b/arch/riscv/include/asm/perf_event.h index 0e638a0c3feb..aefbfaa6a781 100644 --- a/arch/riscv/include/asm/perf_event.h +++ b/arch/riscv/include/asm/perf_event.h @@ -10,6 +10,7 @@ #include <linux/perf_event.h> #include <linux/ptrace.h> +#include <linux/interrupt.h> #define RISCV_BASE_COUNTERS 2 diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h index 85e4220839b0..36016845461d 100644 --- a/arch/riscv/include/asm/smp.h +++ b/arch/riscv/include/asm/smp.h @@ -25,9 +25,6 @@ #ifdef CONFIG_SMP /* SMP initialization hook for setup_arch */ -void __init init_clockevent(void); - -/* SMP initialization hook for setup_arch */ void __init setup_smp(void); /* Hook for the generic smp_call_function_many() routine. */ @@ -44,9 +41,6 @@ void arch_send_call_function_single_ipi(int cpu); */ #define raw_smp_processor_id() (*((int*)((char*)get_current() + TASK_TI_CPU))) -/* Interprocessor interrupt handler */ -irqreturn_t handle_ipi(void); - #endif /* CONFIG_SMP */ #endif /* _ASM_RISCV_SMP_H */ diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 9aaf6c986771..fa2c08e3c05e 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -168,8 +168,8 @@ ENTRY(handle_exception) /* Handle interrupts */ move a0, sp /* pt_regs */ - REG_L a1, handle_arch_irq - jr a1 + move a1, s4 /* scause */ + tail do_IRQ 1: /* Exceptions run with interrupts enabled */ csrs sstatus, SR_SIE diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 6e07ed37bbff..c4d2c63f9a29 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -94,6 +94,7 @@ relocate: or a0, a0, a1 sfence.vma csrw sptbr, a0 +.align 2 1: /* Set trap vector to spin forever to help debug */ la a0, .Lsecondary_park @@ -143,6 +144,7 @@ relocate: tail smp_callin #endif +.align 2 .Lsecondary_park: /* We lack SMP support or have too many harts, so park this hart */ wfi diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c index 7bcdaed15703..0cfac48a1272 100644 --- a/arch/riscv/kernel/irq.c +++ b/arch/riscv/kernel/irq.c @@ -1,21 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2012 Regents of the University of California * Copyright (C) 2017 SiFive - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation, version 2. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. + * Copyright (C) 2018 Christoph Hellwig */ #include <linux/interrupt.h> #include <linux/irqchip.h> #include <linux/irqdomain.h> +/* + * Possible interrupt causes: + */ +#define INTERRUPT_CAUSE_SOFTWARE 1 +#define INTERRUPT_CAUSE_TIMER 5 +#define INTERRUPT_CAUSE_EXTERNAL 9 + +/* + * The high order bit of the trap cause register is always set for + * interrupts, which allows us to differentiate them from exceptions + * quickly. The INTERRUPT_CAUSE_* macros don't contain that bit, so we + * need to mask it off. + */ +#define INTERRUPT_CAUSE_FLAG (1UL << (__riscv_xlen - 1)) + +asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long cause) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + + irq_enter(); + switch (cause & ~INTERRUPT_CAUSE_FLAG) { + case INTERRUPT_CAUSE_TIMER: + riscv_timer_interrupt(); + break; +#ifdef CONFIG_SMP + case INTERRUPT_CAUSE_SOFTWARE: + /* + * We only use software interrupts to pass IPIs, so if a non-SMP + * system gets one, then we don't know what to do. + */ + riscv_software_interrupt(); + break; +#endif + case INTERRUPT_CAUSE_EXTERNAL: + handle_arch_irq(regs); + break; + default: + panic("unexpected interrupt cause"); + } + irq_exit(); + + set_irq_regs(old_regs); +} + void __init init_IRQ(void) { irqchip_init(); diff --git a/arch/riscv/kernel/perf_event.c b/arch/riscv/kernel/perf_event.c index b0e10c4e9f77..a243fae1c1db 100644 --- a/arch/riscv/kernel/perf_event.c +++ b/arch/riscv/kernel/perf_event.c @@ -27,7 +27,6 @@ #include <linux/mutex.h> #include <linux/bitmap.h> #include <linux/irq.h> -#include <linux/interrupt.h> #include <linux/perf_event.h> #include <linux/atomic.h> #include <linux/of.h> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index f0d2070866d4..db20dc630e7e 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -39,6 +39,27 @@ #include <asm/tlbflush.h> #include <asm/thread_info.h> +#ifdef CONFIG_EARLY_PRINTK +static void sbi_console_write(struct console *co, const char *buf, + unsigned int n) +{ + int i; + + for (i = 0; i < n; ++i) { + if (buf[i] == '\n') + sbi_console_putchar('\r'); + sbi_console_putchar(buf[i]); + } +} + +struct console riscv_sbi_early_console_dev __initdata = { + .name = "early", + .write = sbi_console_write, + .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME, + .index = -1 +}; +#endif + #ifdef CONFIG_DUMMY_CONSOLE struct screen_info screen_info = { .orig_video_lines = 30, @@ -195,6 +216,12 @@ static void __init setup_bootmem(void) void __init setup_arch(char **cmdline_p) { +#if defined(CONFIG_EARLY_PRINTK) + if (likely(early_console == NULL)) { + early_console = &riscv_sbi_early_console_dev; + register_console(early_console); + } +#endif *cmdline_p = boot_command_line; parse_early_param(); diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index 6d3962435720..906fe21ea21b 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -45,7 +45,7 @@ int setup_profiling_timer(unsigned int multiplier) return -EINVAL; } -irqreturn_t handle_ipi(void) +void riscv_software_interrupt(void) { unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits; @@ -60,7 +60,7 @@ irqreturn_t handle_ipi(void) ops = xchg(pending_ipis, 0); if (ops == 0) - return IRQ_HANDLED; + return; if (ops & (1 << IPI_RESCHEDULE)) scheduler_ipi(); @@ -73,8 +73,6 @@ irqreturn_t handle_ipi(void) /* Order data access and bit testing. */ mb(); } - - return IRQ_HANDLED; } static void diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c index f741458c5a3f..56abab6a9812 100644 --- a/arch/riscv/kernel/smpboot.c +++ b/arch/riscv/kernel/smpboot.c @@ -104,7 +104,6 @@ asmlinkage void __init smp_callin(void) current->active_mm = mm; trap_init(); - init_clockevent(); notify_cpu_starting(smp_processor_id()); set_cpu_online(smp_processor_id(), 1); local_flush_tlb_all(); diff --git a/arch/riscv/kernel/time.c b/arch/riscv/kernel/time.c index 2463fcca719e..1911c8f6b8a6 100644 --- a/arch/riscv/kernel/time.c +++ b/arch/riscv/kernel/time.c @@ -13,38 +13,11 @@ */ #include <linux/clocksource.h> -#include <linux/clockchips.h> #include <linux/delay.h> - -#ifdef CONFIG_RISCV_TIMER -#include <linux/timer_riscv.h> -#endif - #include <asm/sbi.h> unsigned long riscv_timebase; -DECLARE_PER_CPU(struct clock_event_device, riscv_clock_event); - -void riscv_timer_interrupt(void) -{ -#ifdef CONFIG_RISCV_TIMER - /* - * FIXME: This needs to be cleaned up along with the rest of the IRQ - * handling cleanup. See irq.c for more details. - */ - struct clock_event_device *evdev = this_cpu_ptr(&riscv_clock_event); - - evdev->event_handler(evdev); -#endif -} - -void __init init_clockevent(void) -{ - timer_probe(); - csr_set(sie, SIE_STIE); -} - void __init time_init(void) { struct device_node *cpu; @@ -56,6 +29,5 @@ void __init time_init(void) riscv_timebase = prop; lpj_fine = riscv_timebase / HZ; - - init_clockevent(); + timer_probe(); } diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 81a1952015a6..24a9333dda2c 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -138,7 +138,6 @@ asmlinkage void do_trap_break(struct pt_regs *regs) #endif /* CONFIG_GENERIC_BUG */ force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc), current); - regs->sepc += 0x4; } #ifdef CONFIG_GENERIC_BUG diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile index f6561b783b61..eed1c137f618 100644 --- a/arch/riscv/kernel/vdso/Makefile +++ b/arch/riscv/kernel/vdso/Makefile @@ -52,8 +52,8 @@ $(obj)/%.so: $(obj)/%.so.dbg FORCE # Add -lgcc so rv32 gets static muldi3 and lshrdi3 definitions. # Make sure only to export the intended __vdso_xxx symbol offsets. quiet_cmd_vdsold = VDSOLD $@ - cmd_vdsold = $(CC) $(KCFLAGS) $(call cc-option, -no-pie) -nostdlib $(SYSCFLAGS_$(@F)) \ - -Wl,-T,$(filter-out FORCE,$^) -o $@.tmp -lgcc && \ + cmd_vdsold = $(CC) $(KBUILD_CFLAGS) $(call cc-option, -no-pie) -nostdlib -nostartfiles $(SYSCFLAGS_$(@F)) \ + -Wl,-T,$(filter-out FORCE,$^) -o $@.tmp && \ $(CROSS_COMPILE)objcopy \ $(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@ diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile index 596c2ca40d63..445ec84f9a47 100644 --- a/arch/riscv/lib/Makefile +++ b/arch/riscv/lib/Makefile @@ -2,5 +2,6 @@ lib-y += delay.o lib-y += memcpy.o lib-y += memset.o lib-y += uaccess.o +lib-y += tishift.o lib-$(CONFIG_32BIT) += udivdi3.o diff --git a/arch/riscv/lib/tishift.S b/arch/riscv/lib/tishift.S new file mode 100644 index 000000000000..69abb1277234 --- /dev/null +++ b/arch/riscv/lib/tishift.S @@ -0,0 +1,42 @@ +/* + * Copyright (C) 2018 Free Software Foundation, Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, version 2. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + .globl __lshrti3 +__lshrti3: + beqz a2, .L1 + li a5,64 + sub a5,a5,a2 + addi sp,sp,-16 + sext.w a4,a5 + blez a5, .L2 + sext.w a2,a2 + sll a4,a1,a4 + srl a0,a0,a2 + srl a1,a1,a2 + or a0,a0,a4 + sd a1,8(sp) + sd a0,0(sp) + ld a0,0(sp) + ld a1,8(sp) + addi sp,sp,16 + ret +.L1: + ret +.L2: + negw a4,a4 + srl a1,a1,a4 + sd a1,0(sp) + sd zero,8(sp) + ld a0,0(sp) + ld a1,8(sp) + addi sp,sp,16 + ret diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index dec0dd88ec15..a11f4ba98b05 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -609,4 +609,15 @@ config ATCPIT100_TIMER help This option enables support for the Andestech ATCPIT100 timers. +config RISCV_TIMER + bool "Timer for the RISC-V platform" + depends on RISCV + default y + select TIMER_PROBE + select TIMER_OF + help + This enables the per-hart timer built into all RISC-V systems, which + is accessed via both the SBI and the rdcycle instruction. This is + required for all RISC-V systems. + endmenu diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index c070cc7992e9..db51b2427e8a 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -78,3 +78,4 @@ obj-$(CONFIG_H8300_TPU) += h8300_tpu.o obj-$(CONFIG_CLKSRC_ST_LPC) += clksrc_st_lpc.o obj-$(CONFIG_X86_NUMACHIP) += numachip.o obj-$(CONFIG_ATCPIT100_TIMER) += timer-atcpit100.o +obj-$(CONFIG_RISCV_TIMER) += riscv_timer.o diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/riscv_timer.c new file mode 100644 index 000000000000..4e8b347e43e2 --- /dev/null +++ b/drivers/clocksource/riscv_timer.c @@ -0,0 +1,105 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2012 Regents of the University of California + * Copyright (C) 2017 SiFive + */ +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <linux/cpu.h> +#include <linux/delay.h> +#include <linux/irq.h> +#include <asm/sbi.h> + +/* + * All RISC-V systems have a timer attached to every hart. These timers can be + * read by the 'rdcycle' pseudo instruction, and can use the SBI to setup + * events. In order to abstract the architecture-specific timer reading and + * setting functions away from the clock event insertion code, we provide + * function pointers to the clockevent subsystem that perform two basic + * operations: rdtime() reads the timer on the current CPU, and + * next_event(delta) sets the next timer event to 'delta' cycles in the future. + * As the timers are inherently a per-cpu resource, these callbacks perform + * operations on the current hart. There is guaranteed to be exactly one timer + * per hart on all RISC-V systems. + */ + +static int riscv_clock_next_event(unsigned long delta, + struct clock_event_device *ce) +{ + csr_set(sie, SIE_STIE); + sbi_set_timer(get_cycles64() + delta); + return 0; +} + +static DEFINE_PER_CPU(struct clock_event_device, riscv_clock_event) = { + .name = "riscv_timer_clockevent", + .features = CLOCK_EVT_FEAT_ONESHOT, + .rating = 100, + .set_next_event = riscv_clock_next_event, +}; + +/* + * It is guaranteed that all the timers across all the harts are synchronized + * within one tick of each other, so while this could technically go + * backwards when hopping between CPUs, practically it won't happen. + */ +static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs) +{ + return get_cycles64(); +} + +static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = { + .name = "riscv_clocksource", + .rating = 300, + .mask = CLOCKSOURCE_MASK(BITS_PER_LONG), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .read = riscv_clocksource_rdtime, +}; + +static int riscv_timer_starting_cpu(unsigned int cpu) +{ + struct clock_event_device *ce = per_cpu_ptr(&riscv_clock_event, cpu); + + ce->cpumask = cpumask_of(cpu); + clockevents_config_and_register(ce, riscv_timebase, 100, 0x7fffffff); + + csr_set(sie, SIE_STIE); + return 0; +} + +static int riscv_timer_dying_cpu(unsigned int cpu) +{ + csr_clear(sie, SIE_STIE); + return 0; +} + +/* called directly from the low-level interrupt handler */ +void riscv_timer_interrupt(void) +{ + struct clock_event_device *evdev = this_cpu_ptr(&riscv_clock_event); + + csr_clear(sie, SIE_STIE); + evdev->event_handler(evdev); +} + +static int __init riscv_timer_init_dt(struct device_node *n) +{ + int cpu_id = riscv_of_processor_hart(n), error; + struct clocksource *cs; + + if (cpu_id != smp_processor_id()) + return 0; + + cs = per_cpu_ptr(&riscv_clocksource, cpu_id); + clocksource_register_hz(cs, riscv_timebase); + + error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING, + "clockevents/riscv/timer:starting", + riscv_timer_starting_cpu, riscv_timer_dying_cpu); + if (error) + pr_err("RISCV timer register failed [%d] for cpu = [%d]\n", + error, cpu_id); + return error; +} + +TIMER_OF_DECLARE(riscv_timer, "riscv", riscv_timer_init_dt); diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig index d564d21245c5..383e7b70221d 100644 --- a/drivers/irqchip/Kconfig +++ b/drivers/irqchip/Kconfig @@ -372,3 +372,15 @@ config QCOM_PDC IRQs for Qualcomm Technologies Inc (QTI) mobile chips. endmenu + +config SIFIVE_PLIC + bool "SiFive Platform-Level Interrupt Controller" + depends on RISCV + help + This enables support for the PLIC chip found in SiFive (and + potentially other) RISC-V systems. The PLIC controls devices + interrupts and connects them to each core's local interrupt + controller. Aside from timer and software interrupts, all other + interrupt sources are subordinate to the PLIC. + + If you don't know what to do here, say Y. diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile index 15f268f646bf..fbd1ec8070ef 100644 --- a/drivers/irqchip/Makefile +++ b/drivers/irqchip/Makefile @@ -87,3 +87,4 @@ obj-$(CONFIG_MESON_IRQ_GPIO) += irq-meson-gpio.o obj-$(CONFIG_GOLDFISH_PIC) += irq-goldfish-pic.o obj-$(CONFIG_NDS32) += irq-ativic32.o obj-$(CONFIG_QCOM_PDC) += qcom-pdc.o +obj-$(CONFIG_SIFIVE_PLIC) += irq-sifive-plic.o diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c new file mode 100644 index 000000000000..532e9d68c704 --- /dev/null +++ b/drivers/irqchip/irq-sifive-plic.c @@ -0,0 +1,260 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2017 SiFive + * Copyright (C) 2018 Christoph Hellwig + */ +#define pr_fmt(fmt) "plic: " fmt +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/irq.h> +#include <linux/irqchip.h> +#include <linux/irqdomain.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/platform_device.h> +#include <linux/spinlock.h> + +/* + * This driver implements a version of the RISC-V PLIC with the actual layout + * specified in chapter 8 of the SiFive U5 Coreplex Series Manual: + * + * https://static.dev.sifive.com/U54-MC-RVCoreIP.pdf + * + * The largest number supported by devices marked as 'sifive,plic-1.0.0', is + * 1024, of which device 0 is defined as non-existent by the RISC-V Privileged + * Spec. + */ + +#define MAX_DEVICES 1024 +#define MAX_CONTEXTS 15872 + +/* + * Each interrupt source has a priority register associated with it. + * We always hardwire it to one in Linux. + */ +#define PRIORITY_BASE 0 +#define PRIORITY_PER_ID 4 + +/* + * Each hart context has a vector of interrupt enable bits associated with it. + * There's one bit for each interrupt source. + */ +#define ENABLE_BASE 0x2000 |