From patchwork Sat Aug 4 08:23:17 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 953415 Return-Path: X-Original-To: incoming-dt@patchwork.ozlabs.org Delivered-To: patchwork-incoming-dt@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=devicetree-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=infradead.org header.i=@infradead.org header.b="eKPYZ3yk"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 41jH4h2pMyz9sXc for ; Sat, 4 Aug 2018 18:24:04 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729473AbeHDKXh (ORCPT ); Sat, 4 Aug 2018 06:23:37 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:37520 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726055AbeHDKXh (ORCPT ); Sat, 4 Aug 2018 06:23:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=hEWmJO1h1kDrqPFA/neVJnv6xc8E8nwRi8F+aFXiR0k=; b=eKPYZ3ykdetv6QQNkmixhi8Ot j0wEzdTQyh0qidd2AtPeNaMZxm8QTRmTXaJAEeb/UW0VzRsDEoRjeV2AW+BVDxargC+qhnGLrEd4Q i0qlDrRvKIH+UQqOQbzFkglsa/S5uzqNckQ37xCYBWFFHDbKHv4pSIN5wrYl2FRdj8yg9w4gPCl9g vR5YWotkNfIYiMIOLzQNWpNMNHL9RdKkU4uBWVUIwMuSJxM3wKCn21BqwhKpN2trljhufjuujPLbS 0GhAb+W8LHKc1PW+AxrOuw/hG1PxHmqSFn/sSnymlKCtU6kJzUcxqdJPY1GNlZhqrP3yBNMHvHJQa crgTmVyYg==; Received: from [46.125.249.69] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1flrqg-0003m0-51; Sat, 04 Aug 2018 08:23:42 +0000 From: Christoph Hellwig To: tglx@linutronix.de, palmer@sifive.com, jason@lakedaemon.net, marc.zyngier@arm.com, robh+dt@kernel.org, mark.rutland@arm.com Cc: anup@brainfault.org, atish.patra@wdc.com, devicetree@vger.kernel.org, aou@eecs.berkeley.edu, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, shorne@gmail.com, Palmer Dabbelt Subject: [PATCH 6/8] dt-bindings: interrupt-controller: RISC-V PLIC documentation Date: Sat, 4 Aug 2018 10:23:17 +0200 Message-Id: <20180804082319.5711-7-hch@lst.de> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180804082319.5711-1-hch@lst.de> References: <20180804082319.5711-1-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org From: Palmer Dabbelt This patch adds documentation for the platform-level interrupt controller (PLIC) found in all RISC-V systems. This interrupt controller routes interrupts from all the devices in the system to each hart-local interrupt controller. Note: the DTS bindings for the PLIC aren't set in stone yet, as we might want to change how we're specifying holes in the hart list. Signed-off-by: Palmer Dabbelt [hch: various fixes and updates] Signed-off-by: Christoph Hellwig --- .../interrupt-controller/sifive,plic0.txt | 57 +++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 Documentation/devicetree/bindings/interrupt-controller/sifive,plic0.txt diff --git a/Documentation/devicetree/bindings/interrupt-controller/sifive,plic0.txt b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic0.txt new file mode 100644 index 000000000000..bbfa61cf8d3f --- /dev/null +++ b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic0.txt @@ -0,0 +1,57 @@ +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,plic0" 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 . + +Required properties: +- compatible : "sifive,plic0". +- #address-cells : should be <0>. +- #interrupt-cells : should be <1>. +- 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. The nodes pointed + to should be "riscv" HART nodes, or eventually be parented by such nodes. +- riscv,ndev: Specifies how many external interrupts are supported by + this controller. + +Example: + + plic: interrupt-controller@c000000 { + #address-cells = <0>; + #interrupt-cells = <1>; + compatible = "riscv,plic0"; + 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>; + };