From patchwork Mon Jun 24 05:43:05 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11012193 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0FBCE76 for ; Mon, 24 Jun 2019 05:43:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F31FC28B01 for ; Mon, 24 Jun 2019 05:43:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E704B28B1E; Mon, 24 Jun 2019 05:43:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 4AFDA28B01 for ; Mon, 24 Jun 2019 05:43:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=oScOKtJ4cpdLmoh27Alh5uiuFydPkPy80F7b9A6EYlM=; b=I09QB4i/khsRx+ atqXMqjzNJg53eUgIBW2OGf+9EwBv946gqs4z66WC3SS5LfSfDD3wGIzRjIJ1O8CUQJwbkFCOcmmT fBKP/q0taJ+PmgSR1TKM+TP4MrAb+cwcmYPgwfBsXQ9TNK922JSvJ8lLUvtw5ER0zP7zBL6RD8jBK gzhTU/N9MCmiJcn+IZWeEyeBFBsfYki/B587ufkNaEPhzB7ytn9KzXkvdpCEblbBiIqS9FpxXu+tZ V9Bo2jYBE/V2+T0CpzS0mZ3/U2kLlAQCFzV2UYsUbiGWgv3gwB/2myd119hCUtDJPmKb6UOX0xn4+ QNT2yWBu/OykbJJQdh6Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hfHli-0006hd-Vm; Mon, 24 Jun 2019 05:43:55 +0000 Received: from 213-225-6-159.nat.highway.a1.net ([213.225.6.159] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hfHlg-0006c3-P1; Mon, 24 Jun 2019 05:43:53 +0000 From: Christoph Hellwig To: Palmer Dabbelt , Paul Walmsley Subject: [PATCH 11/17] riscv: provide native clint access for M-mode Date: Mon, 24 Jun 2019 07:43:05 +0200 Message-Id: <20190624054311.30256-12-hch@lst.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190624054311.30256-1-hch@lst.de> References: <20190624054311.30256-1-hch@lst.de> MIME-Version: 1.0 X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mm@kvack.org, Damien Le Moal , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Sender: "linux-riscv" Errors-To: linux-riscv-bounces+patchwork-linux-riscv=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP RISC-V has the concept of a cpu level interrupt controller. Part of it is expose as bits in the status registers, and 2 new CSRs per privilege level in the instruction set, but the machanisms to trigger IPIs and timer events, as well as reading the actual timer value are not specified in the RISC-V spec but usually delegated to a block of MMIO registers. This patch adds support for those MMIO registers in the timer and IPI code. For now only the SiFive layout also supported by a few other implementations is supported, but the code should be easily extensible to others in the future. Signed-off-by: Christoph Hellwig --- arch/riscv/include/asm/clint.h | 40 +++++++++++++++++++++++++++ arch/riscv/include/asm/timex.h | 17 ++++++++++++ arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/clint.c | 45 +++++++++++++++++++++++++++++++ arch/riscv/kernel/setup.c | 2 ++ arch/riscv/kernel/smp.c | 24 +++++++++++++++++ arch/riscv/kernel/smpboot.c | 3 +++ drivers/clocksource/timer-riscv.c | 16 ++++++++--- 8 files changed, 144 insertions(+), 4 deletions(-) create mode 100644 arch/riscv/include/asm/clint.h create mode 100644 arch/riscv/kernel/clint.c diff --git a/arch/riscv/include/asm/clint.h b/arch/riscv/include/asm/clint.h new file mode 100644 index 000000000000..46d182d9a4db --- /dev/null +++ b/arch/riscv/include/asm/clint.h @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifndef _ASM_CLINT_H +#define _ASM_CLINT_H 1 + +#include + +#ifdef CONFIG_M_MODE +extern u32 __iomem *clint_ipi_base; +extern u64 __iomem *clint_time_val; +extern u64 __iomem *clint_time_cmp; + +void clint_init_boot_cpu(void); + +static inline void clint_send_ipi(unsigned long hartid) +{ + writel(1, clint_ipi_base + hartid); +} + +static inline void clint_clear_ipi(unsigned long hartid) +{ + writel(0, clint_ipi_base + hartid); +} + +static inline u64 clint_read_timer(void) +{ + return readq_relaxed(clint_time_val); +} + +static inline void clint_set_timer(unsigned long delta) +{ + writeq_relaxed(clint_read_timer() + delta, + clint_time_cmp + cpuid_to_hartid_map(smp_processor_id())); +} + +#else +#define clint_init_boot_cpu() do { } while (0) +#define clint_clear_ipi(hartid) do { } while (0) +#endif /* CONFIG_M_MODE */ + +#endif /* _ASM_CLINT_H */ diff --git a/arch/riscv/include/asm/timex.h b/arch/riscv/include/asm/timex.h index 6a703ec9d796..bf907997f107 100644 --- a/arch/riscv/include/asm/timex.h +++ b/arch/riscv/include/asm/timex.h @@ -10,6 +10,22 @@ typedef unsigned long cycles_t; +#ifdef CONFIG_M_MODE + +#include +#include + +static inline cycles_t get_cycles(void) +{ +#ifdef CONFIG_64BIT + return readq_relaxed(clint_time_val); +#else + return readl_relaxed(clint_time_val); +#endif +} +#define get_cycles get_cycles + +#else /* CONFIG_M_MODE */ static inline cycles_t get_cycles_inline(void) { cycles_t n; @@ -40,6 +56,7 @@ static inline uint64_t get_cycles64(void) return ((u64)hi << 32) | lo; } #endif +#endif /* CONFIG_M_MODE */ #define ARCH_HAS_READ_CURRENT_TIMER diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 2420d37d96de..f933c04f89db 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -29,6 +29,7 @@ obj-y += vdso.o obj-y += cacheinfo.o obj-y += vdso/ +obj-$(CONFIG_M_MODE) += clint.o obj-$(CONFIG_FPU) += fpu.o obj-$(CONFIG_SMP) += smpboot.o obj-$(CONFIG_SMP) += smp.o diff --git a/arch/riscv/kernel/clint.c b/arch/riscv/kernel/clint.c new file mode 100644 index 000000000000..15b9e7fa5416 --- /dev/null +++ b/arch/riscv/kernel/clint.c @@ -0,0 +1,45 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019 Christoph Hellwig. + */ + +#include +#include +#include +#include +#include +#include + +/* + * This is the layout used by the SiFive clint, which is also shared by the qemu + * virt platform, and the Kendryte KD210 at least. + */ +#define CLINT_IPI_OFF 0 +#define CLINT_TIME_VAL_OFF 0xbff8 +#define CLINT_TIME_CMP_OFF 0x4000; + +u32 __iomem *clint_ipi_base; +u64 __iomem *clint_time_val; +u64 __iomem *clint_time_cmp; + +void clint_init_boot_cpu(void) +{ + struct device_node *np; + void __iomem *base; + + np = of_find_compatible_node(NULL, NULL, "riscv,clint0"); + if (!np) { + panic("clint not found"); + return; + } + + base = of_iomap(np, 0); + if (!base) + panic("could not map CLINT"); + + clint_ipi_base = base + CLINT_IPI_OFF; + clint_time_val = base + CLINT_TIME_VAL_OFF; + clint_time_cmp = base + CLINT_TIME_CMP_OFF; + + clint_clear_ipi(boot_cpu_hartid); +} diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index b92e6831d1ec..2892d82f474c 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -17,6 +17,7 @@ #include #include +#include #include #include #include @@ -67,6 +68,7 @@ void __init setup_arch(char **cmdline_p) setup_bootmem(); paging_init(); unflatten_device_tree(); + clint_init_boot_cpu(); #ifdef CONFIG_SWIOTLB swiotlb_init(1); diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index 8cd730239613..ee8599a7ca48 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -13,7 +13,9 @@ #include #include #include +#include +#include #include #include #include @@ -78,6 +80,27 @@ static void ipi_stop(void) wait_for_interrupt(); } +#ifdef CONFIG_M_MODE +static inline void send_ipi_single(int cpu, enum ipi_message_type op) +{ + set_bit(op, &ipi_data[cpu].bits); + clint_send_ipi(cpuid_to_hartid_map(cpu)); +} + +static inline void send_ipi_mask(const struct cpumask *mask, + enum ipi_message_type op) +{ + int cpu; + + for_each_cpu(cpu, mask) + send_ipi_single(cpu, op); +} + +static inline void clear_ipi(void) +{ + clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id())); +} +#else /* CONFIG_M_MODE */ static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op) { int cpuid, hartid; @@ -103,6 +126,7 @@ static inline void clear_ipi(void) { csr_clear(CSR_SIP, SIE_SSIE); } +#endif /* CONFIG_M_MODE */ void riscv_software_interrupt(void) { diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c index 7462a44304fe..1b7678d86ec8 100644 --- a/arch/riscv/kernel/smpboot.c +++ b/arch/riscv/kernel/smpboot.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -132,6 +133,8 @@ asmlinkage void __init smp_callin(void) { struct mm_struct *mm = &init_mm; + clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id())); + /* All kernel threads share the same mm context. */ mmgrab(mm); current->active_mm = mm; diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c index 2e2d363faabf..008af21611d9 100644 --- a/drivers/clocksource/timer-riscv.c +++ b/drivers/clocksource/timer-riscv.c @@ -24,12 +24,16 @@ * 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(CSR_XIE, XIE_XTIE); + +#ifdef CONFIG_M_MODE + clint_set_timer(delta); +#else sbi_set_timer(get_cycles64() + delta); +#endif return 0; } @@ -45,14 +49,18 @@ static DEFINE_PER_CPU(struct clock_event_device, riscv_clock_event) = { * 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) +static u64 riscv_sched_clock(void) { +#ifdef CONFIG_M_MODE + return clint_read_timer(); +#else return get_cycles64(); +#endif } -static u64 riscv_sched_clock(void) +static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs) { - return get_cycles64(); + return riscv_sched_clock(); } static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = {