From patchwork Fri May 29 00:25:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 199789 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6551C433DF for ; Fri, 29 May 2020 00:25:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C37F8208DB for ; Fri, 29 May 2020 00:25:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2438022AbgE2AZw (ORCPT ); Thu, 28 May 2020 20:25:52 -0400 Received: from relay12.mail.gandi.net ([217.70.178.232]:34029 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2438021AbgE2AZv (ORCPT ); Thu, 28 May 2020 20:25:51 -0400 Received: from localhost.localdomain (unknown [91.224.148.103]) (Authenticated sender: miquel.raynal@bootlin.com) by relay12.mail.gandi.net (Postfix) with ESMTPSA id 9AE11200007; Fri, 29 May 2020 00:25:47 +0000 (UTC) From: Miquel Raynal To: Richard Weinberger , Vignesh Raghavendra , Tudor Ambarus , , Rob Herring , Mark Rutland , Cc: Boris Brezillon , Thomas Petazzoni , Paul Cercueil , Chuanhong Guo , Weijie Gao , , Mason Yang , Julien Su , Miquel Raynal Subject: [PATCH v7 15/20] mtd: nand: Introduce the ECC engine abstraction Date: Fri, 29 May 2020 02:25:12 +0200 Message-Id: <20200529002517.3546-16-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200529002517.3546-1-miquel.raynal@bootlin.com> References: <20200529002517.3546-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Create a generic ECC engine object. Later the ecc.c file will receive more generic code coming from the raw NAND specific part. This is a base to instantiate ECC engine objects. Signed-off-by: Miquel Raynal --- drivers/mtd/nand/Kconfig | 8 ++ drivers/mtd/nand/Makefile | 2 + drivers/mtd/nand/ecc.c | 157 ++++++++++++++++++++++++++++++++++++++ include/linux/mtd/nand.h | 67 ++++++++++++++++ 4 files changed, 234 insertions(+) create mode 100644 drivers/mtd/nand/ecc.c diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig index c1a45b071165..263d474d091c 100644 --- a/drivers/mtd/nand/Kconfig +++ b/drivers/mtd/nand/Kconfig @@ -9,4 +9,12 @@ source "drivers/mtd/nand/onenand/Kconfig" source "drivers/mtd/nand/raw/Kconfig" source "drivers/mtd/nand/spi/Kconfig" +menu "ECC engine support" + +config MTD_NAND_ECC + bool + depends on MTD_NAND_CORE + +endmenu + endmenu diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile index 7ecd80c0a66e..981372953b56 100644 --- a/drivers/mtd/nand/Makefile +++ b/drivers/mtd/nand/Makefile @@ -6,3 +6,5 @@ obj-$(CONFIG_MTD_NAND_CORE) += nandcore.o obj-y += onenand/ obj-y += raw/ obj-y += spi/ + +nandcore-$(CONFIG_MTD_NAND_ECC) += ecc.o diff --git a/drivers/mtd/nand/ecc.c b/drivers/mtd/nand/ecc.c new file mode 100644 index 000000000000..f7300ba37167 --- /dev/null +++ b/drivers/mtd/nand/ecc.c @@ -0,0 +1,157 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Generic Error-Correcting Code (ECC) engine + * + * Copyright (C) 2019 Macronix + * Author: + * Miquèl RAYNAL + * + * + * This file describes the abstraction of any NAND ECC engine. It has been + * designed to fit most cases, including parallel NANDs and SPI-NANDs. + * + * There are three main situations where instantiating this ECC engine makes + * sense: + * - external: The ECC engine is outside the NAND pipeline, typically this + * is a software ECC engine, or an hardware engine that is + * outside the NAND controller pipeline. + * - pipelined: The ECC engine is inside the NAND pipeline, ie. on the + * controller's side. This is the case of most of the raw NAND + * controllers. In the pipeline case, the ECC bytes are + * generated/data corrected on the fly when a page is + * written/read. + * - ondie: The ECC engine is inside the NAND pipeline, on the chip's side. + * Some NAND chips can correct themselves the data. + * + * Besides the initial setup and final cleanups, the interfaces are rather + * simple: + * - prepare: Prepare an I/O request. Enable/disable the ECC engine based on + * the I/O request type. In case of software correction or external + * engine, this step may involve to derive the ECC bytes and place + * them in the OOB area before a write. + * - finish: Finish an I/O request. Correct the data in case of a read + * request and report the number of corrected bits/uncorrectable + * errors. Most likely empty for write operations, unless you have + * hardware specific stuff to do, like shutting down the engine to + * save power. + * + * The I/O request should be enclosed in a prepare()/finish() pair of calls + * and will behave differently depending on the requested I/O type: + * - raw: Correction disabled + * - ecc: Correction enabled + * + * The request direction is impacting the logic as well: + * - read: Load data from the NAND chip + * - write: Store data in the NAND chip + * + * Mixing all this combinations together gives the following behavior. + * Those are just examples, drivers are free to add custom steps in their + * prepare/finish hook. + * + * [external ECC engine] + * - external + prepare + raw + read: do nothing + * - external + finish + raw + read: do nothing + * - external + prepare + raw + write: do nothing + * - external + finish + raw + write: do nothing + * - external + prepare + ecc + read: do nothing + * - external + finish + ecc + read: calculate expected ECC bytes, extract + * ECC bytes from OOB buffer, correct + * and report any bitflip/error + * - external + prepare + ecc + write: calculate ECC bytes and store them at + * the right place in the OOB buffer based + * on the OOB layout + * - external + finish + ecc + write: do nothing + * + * [pipelined ECC engine] + * - pipelined + prepare + raw + read: disable the controller's ECC engine if + * activated + * - pipelined + finish + raw + read: do nothing + * - pipelined + prepare + raw + write: disable the controller's ECC engine if + * activated + * - pipelined + finish + raw + write: do nothing + * - pipelined + prepare + ecc + read: enable the controller's ECC engine if + * deactivated + * - pipelined + finish + ecc + read: check the status, report any + * error/bitflip + * - pipelined + prepare + ecc + write: enable the controller's ECC engine if + * deactivated + * - pipelined + finish + ecc + write: do nothing + * + * [ondie ECC engine] + * - ondie + prepare + raw + read: send commands to disable the on-chip ECC + * engine if activated + * - ondie + finish + raw + read: do nothing + * - ondie + prepare + raw + write: send commands to disable the on-chip ECC + * engine if activated + * - ondie + finish + raw + write: do nothing + * - ondie + prepare + ecc + read: send commands to enable the on-chip ECC + * engine if deactivated + * - ondie + finish + ecc + read: send commands to check the status, report + * any error/bitflip + * - ondie + prepare + ecc + write: send commands to enable the on-chip ECC + * engine if deactivated + * - ondie + finish + ecc + write: do nothing + */ + +#include +#include + +/** + * nand_ecc_init_ctx - Init the ECC engine context + * @nand: the NAND device + * + * On success, the caller is responsible of calling @nand_ecc_cleanup_ctx(). + */ +int nand_ecc_init_ctx(struct nand_device *nand) +{ + if (!nand->ecc.engine->ops->init_ctx) + return 0; + + return nand->ecc.engine->ops->init_ctx(nand); +} +EXPORT_SYMBOL(nand_ecc_init_ctx); + +/** + * nand_ecc_cleanup_ctx - Cleanup the ECC engine context + * @nand: the NAND device + */ +void nand_ecc_cleanup_ctx(struct nand_device *nand) +{ + if (nand->ecc.engine->ops->cleanup_ctx) + nand->ecc.engine->ops->cleanup_ctx(nand); +} +EXPORT_SYMBOL(nand_ecc_cleanup_ctx); + +/** + * nand_ecc_prepare_io_req - Prepare an I/O request + * @nand: the NAND device + * @req: the I/O request + */ +int nand_ecc_prepare_io_req(struct nand_device *nand, + struct nand_page_io_req *req) +{ + if (!nand->ecc.engine->ops->prepare_io_req) + return 0; + + return nand->ecc.engine->ops->prepare_io_req(nand, req); +} +EXPORT_SYMBOL(nand_ecc_prepare_io_req); + +/** + * nand_ecc_finish_io_req - Finish an I/O request + * @nand: the NAND device + * @req: the I/O request + */ +int nand_ecc_finish_io_req(struct nand_device *nand, + struct nand_page_io_req *req) +{ + if (!nand->ecc.engine->ops->finish_io_req) + return 0; + + return nand->ecc.engine->ops->finish_io_req(nand, req); +} +EXPORT_SYMBOL(nand_ecc_finish_io_req); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Miquel Raynal "); +MODULE_DESCRIPTION("Generic ECC engine"); diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 9aacdf9dc779..2f838394b5f7 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -219,6 +219,73 @@ struct nand_ops { bool (*isbad)(struct nand_device *nand, const struct nand_pos *pos); }; +/** + * struct nand_ecc_context - Context for the ECC engine + * @conf: basic ECC engine parameters + * @total: total number of bytes used for storing ECC codes, this is used by + * generic OOB layouts + * @priv: ECC engine driver private data + */ +struct nand_ecc_context { + struct nand_ecc_props conf; + unsigned int total; + void *priv; +}; + +/** + * struct nand_ecc_engine_ops - ECC engine operations + * @init_ctx: given a desired user configuration for the pointed NAND device, + * requests the ECC engine driver to setup a configuration with + * values it supports. + * @cleanup_ctx: clean the context initialized by @init_ctx. + * @prepare_io_req: is called before reading/writing a page to prepare the I/O + * request to be performed with ECC correction. + * @finish_io_req: is called after reading/writing a page to terminate the I/O + * request and ensure proper ECC correction. + */ +struct nand_ecc_engine_ops { + int (*init_ctx)(struct nand_device *nand); + void (*cleanup_ctx)(struct nand_device *nand); + int (*prepare_io_req)(struct nand_device *nand, + struct nand_page_io_req *req); + int (*finish_io_req)(struct nand_device *nand, + struct nand_page_io_req *req); +}; + +/** + * struct nand_ecc_engine - ECC engine abstraction for NAND devices + * @ops: ECC engine operations + */ +struct nand_ecc_engine { + struct nand_ecc_engine_ops *ops; +}; + +int nand_ecc_init_ctx(struct nand_device *nand); +void nand_ecc_cleanup_ctx(struct nand_device *nand); +int nand_ecc_prepare_io_req(struct nand_device *nand, + struct nand_page_io_req *req); +int nand_ecc_finish_io_req(struct nand_device *nand, + struct nand_page_io_req *req); + +/** + * struct nand_ecc - Information relative to the ECC + * @defaults: Default values, depend on the underlying subsystem + * @requirements: ECC requirements from the NAND chip perspective + * @user_conf: User desires in terms of ECC parameters + * @ctx: ECC context for the ECC engine, derived from the device @requirements + * the @user_conf and the @defaults + * @ondie_engine: On-die ECC engine reference, if any + * @engine: ECC engine actually bound + */ +struct nand_ecc { + struct nand_ecc_props defaults; + struct nand_ecc_props requirements; + struct nand_ecc_props user_conf; + struct nand_ecc_context ctx; + struct nand_ecc_engine *ondie_engine; + struct nand_ecc_engine *engine; +}; + /** * struct nand_device - NAND device * @mtd: MTD instance attached to the NAND device