From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9A59C433FE for ; Thu, 7 Oct 2021 12:09:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1F4561262 for ; Thu, 7 Oct 2021 12:09:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241269AbhJGMK7 (ORCPT ); Thu, 7 Oct 2021 08:10:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:50666 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241267AbhJGMKl (ORCPT ); Thu, 7 Oct 2021 08:10:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id EB69961262; Thu, 7 Oct 2021 12:08:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1633608527; bh=MAGFFzqURGwDQH/Uo4hKzd/lQxtzLSBieu8FF4wspJI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XMeeyh/3koc4pxtWJMrFxk7WewrYMTfIM3MT0q7fxA1w9CvGBeNidWf4J3+TGMQ/J TjHUv7NhSkKq0z3m8Z/ktLF94SuoTVxYrnE/xLJ7dJ8qxX28VRswHJfcW3MyWj4i2v 77MV7dXayO312qCyjcGPDxaXRkTTQmdCXfHdAQU1ylJXNOyhyN+6Rp7yxR0EyxDiSd K9KdKPDYtprhsTBBQLRjPAJ9nqGy0aiLH3825WVMTtYSjBN1gxBrKkPwGxzA+bEduv mq0HgZTDw1WrlnV2A8qQOF/iG3lCfwjm7carpJjrORU+rOiagMZ/cGaPu6Rcuiu4/Z f4GdvVHKDj3tw== From: Roger Quadros To: tony@atomide.com Cc: robh+dt@kernel.org, grygorii.strashko@ti.com, nm@ti.com, lokeshvutla@ti.com, nsekhar@ti.com, krzysztof.kozlowski@canonical.com, miquel.raynal@bootlin.com, devicetree@vger.kernel.org, linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, Roger Quadros Subject: [PATCH v5 4/8] dt-bindings: mtd: ti,gpmc-nand: Convert to yaml Date: Thu, 7 Oct 2021 15:08:26 +0300 Message-Id: <20211007120830.17221-5-rogerq@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211007120830.17221-1-rogerq@kernel.org> References: <20211007120830.17221-1-rogerq@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Convert gpmc-nand.txt to ti,gpmc-nand.yaml. Signed-off-by: Roger Quadros Reviewed-by: Rob Herring --- .../devicetree/bindings/mtd/gpmc-nand.txt | 147 ------------------ .../devicetree/bindings/mtd/ti,gpmc-nand.yaml | 121 ++++++++++++++ 2 files changed, 121 insertions(+), 147 deletions(-) delete mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt create mode 100644 Documentation/devicetree/bindings/mtd/ti,gpmc-nand.yaml diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt deleted file mode 100644 index c459f169a904..000000000000 --- a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt +++ /dev/null @@ -1,147 +0,0 @@ -Device tree bindings for GPMC connected NANDs - -GPMC connected NAND (found on OMAP boards) are represented as child nodes of -the GPMC controller with a name of "nand". - -All timing relevant properties as well as generic gpmc child properties are -explained in a separate documents - please refer to -Documentation/devicetree/bindings/memory-controllers/omap-gpmc.txt - -For NAND specific properties such as ECC modes or bus width, please refer to -Documentation/devicetree/bindings/mtd/nand-controller.yaml - - -Required properties: - - - compatible: "ti,omap2-nand" - - reg: range id (CS number), base offset and length of the - NAND I/O space - - interrupts: Two interrupt specifiers, one for fifoevent, one for termcount. - -Optional properties: - - - nand-bus-width: Set this numeric value to 16 if the hardware - is wired that way. If not specified, a bus - width of 8 is assumed. - - - ti,nand-ecc-opt: A string setting the ECC layout to use. One of: - "sw" 1-bit Hamming ecc code via software - "hw" use "ham1" instead - "hw-romcode" use "ham1" instead - "ham1" 1-bit Hamming ecc code - "bch4" 4-bit BCH ecc code - "bch8" 8-bit BCH ecc code - "bch16" 16-bit BCH ECC code - Refer below "How to select correct ECC scheme for your device ?" - - - ti,nand-xfer-type: A string setting the data transfer type. One of: - - "prefetch-polled" Prefetch polled mode (default) - "polled" Polled mode, without prefetch - "prefetch-dma" Prefetch enabled DMA mode - "prefetch-irq" Prefetch enabled irq mode - - - elm_id: use "ti,elm-id" instead - - ti,elm-id: Specifies phandle of the ELM devicetree node. - ELM is an on-chip hardware engine on TI SoC which is used for - locating ECC errors for BCHx algorithms. SoC devices which have - ELM hardware engines should specify this device node in .dtsi - Using ELM for ECC error correction frees some CPU cycles. - - rb-gpios: GPIO specifier for the ready/busy# pin. - -For inline partition table parsing (optional): - - - #address-cells: should be set to 1 - - #size-cells: should be set to 1 - -Example for an AM33xx board: - - gpmc: gpmc@50000000 { - compatible = "ti,am3352-gpmc"; - ti,hwmods = "gpmc"; - reg = <0x50000000 0x36c>; - interrupts = <100>; - gpmc,num-cs = <8>; - gpmc,num-waitpins = <2>; - #address-cells = <2>; - #size-cells = <1>; - ranges = <0 0 0x08000000 0x1000000>; /* CS0 space, 16MB */ - elm_id = <&elm>; - interrupt-controller; - #interrupt-cells = <2>; - - nand@0,0 { - compatible = "ti,omap2-nand"; - reg = <0 0 4>; /* CS0, offset 0, NAND I/O window 4 */ - interrupt-parent = <&gpmc>; - interrupts = <0 IRQ_TYPE_NONE>, <1 IRQ_TYPE NONE>; - nand-bus-width = <16>; - ti,nand-ecc-opt = "bch8"; - ti,nand-xfer-type = "polled"; - rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */ - - gpmc,sync-clk-ps = <0>; - gpmc,cs-on-ns = <0>; - gpmc,cs-rd-off-ns = <44>; - gpmc,cs-wr-off-ns = <44>; - gpmc,adv-on-ns = <6>; - gpmc,adv-rd-off-ns = <34>; - gpmc,adv-wr-off-ns = <44>; - gpmc,we-off-ns = <40>; - gpmc,oe-off-ns = <54>; - gpmc,access-ns = <64>; - gpmc,rd-cycle-ns = <82>; - gpmc,wr-cycle-ns = <82>; - gpmc,wr-access-ns = <40>; - gpmc,wr-data-mux-bus-ns = <0>; - - #address-cells = <1>; - #size-cells = <1>; - - /* partitions go here */ - }; - }; - -How to select correct ECC scheme for your device ? --------------------------------------------------- -Higher ECC scheme usually means better protection against bit-flips and -increased system lifetime. However, selection of ECC scheme is dependent -on various other factors also like; - -(1) support of built in hardware engines. - Some legacy OMAP SoC do not have ELM harware engine, so those SoC cannot - support ecc-schemes with hardware error-correction (BCHx_HW). However - such SoC can use ecc-schemes with software library for error-correction - (BCHx_HW_DETECTION_SW). The error correction capability with software - library remains equivalent to their hardware counter-part, but there is - slight CPU penalty when too many bit-flips are detected during reads. - -(2) Device parameters like OOBSIZE. - Other factor which governs the selection of ecc-scheme is oob-size. - Higher ECC schemes require more OOB/Spare area to store ECC syndrome, - so the device should have enough free bytes available its OOB/Spare - area to accommodate ECC for entire page. In general following expression - helps in determining if given device can accommodate ECC syndrome: - "2 + (PAGESIZE / 512) * ECC_BYTES" <= OOBSIZE" - where - OOBSIZE number of bytes in OOB/spare area - PAGESIZE number of bytes in main-area of device page - ECC_BYTES number of ECC bytes generated to protect - 512 bytes of data, which is: - '3' for HAM1_xx ecc schemes - '7' for BCH4_xx ecc schemes - '14' for BCH8_xx ecc schemes - '26' for BCH16_xx ecc schemes - - Example(a): For a device with PAGESIZE = 2048 and OOBSIZE = 64 and - trying to use BCH16 (ECC_BYTES=26) ecc-scheme. - Number of ECC bytes per page = (2 + (2048 / 512) * 26) = 106 B - which is greater than capacity of NAND device (OOBSIZE=64) - Hence, BCH16 cannot be supported on given device. But it can - probably use lower ecc-schemes like BCH8. - - Example(b): For a device with PAGESIZE = 2048 and OOBSIZE = 128 and - trying to use BCH16 (ECC_BYTES=26) ecc-scheme. - Number of ECC bytes per page = (2 + (2048 / 512) * 26) = 106 B - which can be accommodated in the OOB/Spare area of this device - (OOBSIZE=128). So this device can use BCH16 ecc-scheme. diff --git a/Documentation/devicetree/bindings/mtd/ti,gpmc-nand.yaml b/Documentation/devicetree/bindings/mtd/ti,gpmc-nand.yaml new file mode 100644 index 000000000000..beb26b9bcfb2 --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/ti,gpmc-nand.yaml @@ -0,0 +1,121 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/mtd/ti,gpmc-nand.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Texas Instruments GPMC NAND Flash controller. + +maintainers: + - Tony Lindgren + - Roger Quadros + +description: + GPMC NAND controller/Flash is represented as a child of the + GPMC controller node. + +properties: + compatible: + const: ti,omap2-nand + + reg: + maxItems: 1 + + interrupts: + items: + - description: Interrupt for fifoevent + - description: Interrupt for termcount + + "#address-cells": true + + "#size-cells": true + + ti,nand-ecc-opt: + description: Desired ECC algorithm + $ref: /schemas/types.yaml#/definitions/string + enum: [sw, ham1, bch4, bch8, bch16] + + ti,nand-xfer-type: + description: Data transfer method between controller and chip. + $ref: /schemas/types.yaml#/definitions/string + enum: [prefetch-polled, polled, prefetch-dma, prefetch-irq] + default: prefetch-polled + + ti,elm-id: + description: + phandle to the ELM (Error Location Module). + $ref: /schemas/types.yaml#/definitions/phandle + + nand-bus-width: + description: + Bus width to the NAND chip + $ref: /schemas/types.yaml#/definitions/uint32 + enum: [8, 16] + default: 8 + +patternProperties: + "@[0-9a-f]+$": + $ref: "/schemas/mtd/partitions/partition.yaml" + +allOf: + - $ref: "/schemas/memory-controllers/ti,gpmc-child.yaml" + +required: + - compatible + - reg + - ti,nand-ecc-opt + +unevaluatedProperties: false + +examples: + - | + #include + #include + + gpmc: memory-controller@50000000 { + compatible = "ti,am3352-gpmc"; + dmas = <&edma 52 0>; + dma-names = "rxtx"; + clocks = <&l3s_gclk>; + clock-names = "fck"; + reg = <0x50000000 0x2000>; + interrupts = ; + gpmc,num-cs = <7>; + gpmc,num-waitpins = <2>; + #address-cells = <2>; + #size-cells = <1>; + interrupt-controller; + #interrupt-cells = <2>; + gpio-controller; + #gpio-cells = <2>; + + ranges = <0 0 0x08000000 0x01000000>; /* CS0 space. Min partition = 16MB */ + nand@0,0 { + compatible = "ti,omap2-nand"; + reg = <0 0 4>; /* device IO registers */ + interrupt-parent = <&gpmc>; + interrupts = <0 IRQ_TYPE_NONE>, /* fifoevent */ + <1 IRQ_TYPE_NONE>; /* termcount */ + ti,nand-xfer-type = "prefetch-dma"; + ti,nand-ecc-opt = "bch16"; + ti,elm-id = <&elm>; + #address-cells = <1>; + #size-cells = <1>; + + /* NAND generic properties */ + nand-bus-width = <8>; + rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */ + + /* GPMC properties*/ + gpmc,device-width = <1>; + + partition@0 { + label = "NAND.SPL"; + reg = <0x00000000 0x00040000>; + }; + partition@1 { + label = "NAND.SPL.backup1"; + reg = <0x00040000 0x00040000>; + }; + }; + }; -- 2.17.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50970C433F5 for ; Thu, 7 Oct 2021 12:10:23 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1340960F90 for ; Thu, 7 Oct 2021 12:10:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1340960F90 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=wLci8PtUovWDtv2bKSgeeDj/1kqgFPOrZJx2d3kPfDM=; b=JCNbje7T654ncu SdVEAZGEnJjH7kDMlG66PDpAmoUs7Yykjuw5eymDcjquw9X8RT6KOSF1rAgRrOd+sjWYSslugl4IJ lwC1IriccDlb+A5ne81A2pyU730CrWK1q+sD/VtA3UWM933ViGbsdGvlcSsPYg4MKDnGL33PLu4jY KTcqC4pb25bcV5yFtZSu38N1aUunDlrz5wefm/e0qHhUumM0YcmY/bycogPBY21pge/+yJRMI6B+d mzYOuANJMKIv7yzh42G3LVQ/fKIC9NcJhgdP0V3trsFFiQYKsq/ohRntyJFeZ9JxIWM7IVG/a0xID y+xDdap7gwEk7a3zOuZQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mYSDX-00HC8u-Uv; Thu, 07 Oct 2021 12:09:44 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mYSCd-00HBpY-Nn for linux-mtd@lists.infradead.org; Thu, 07 Oct 2021 12:08:49 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id EB69961262; Thu, 7 Oct 2021 12:08:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1633608527; bh=MAGFFzqURGwDQH/Uo4hKzd/lQxtzLSBieu8FF4wspJI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XMeeyh/3koc4pxtWJMrFxk7WewrYMTfIM3MT0q7fxA1w9CvGBeNidWf4J3+TGMQ/J TjHUv7NhSkKq0z3m8Z/ktLF94SuoTVxYrnE/xLJ7dJ8qxX28VRswHJfcW3MyWj4i2v 77MV7dXayO312qCyjcGPDxaXRkTTQmdCXfHdAQU1ylJXNOyhyN+6Rp7yxR0EyxDiSd K9KdKPDYtprhsTBBQLRjPAJ9nqGy0aiLH3825WVMTtYSjBN1gxBrKkPwGxzA+bEduv mq0HgZTDw1WrlnV2A8qQOF/iG3lCfwjm7carpJjrORU+rOiagMZ/cGaPu6Rcuiu4/Z f4GdvVHKDj3tw== From: Roger Quadros To: tony@atomide.com Cc: robh+dt@kernel.org, grygorii.strashko@ti.com, nm@ti.com, lokeshvutla@ti.com, nsekhar@ti.com, krzysztof.kozlowski@canonical.com, miquel.raynal@bootlin.com, devicetree@vger.kernel.org, linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, Roger Quadros Subject: [PATCH v5 4/8] dt-bindings: mtd: ti,gpmc-nand: Convert to yaml Date: Thu, 7 Oct 2021 15:08:26 +0300 Message-Id: <20211007120830.17221-5-rogerq@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211007120830.17221-1-rogerq@kernel.org> References: <20211007120830.17221-1-rogerq@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211007_050847_843664_CC98FBE0 X-CRM114-Status: GOOD ( 23.25 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org Convert gpmc-nand.txt to ti,gpmc-nand.yaml. Signed-off-by: Roger Quadros Reviewed-by: Rob Herring --- .../devicetree/bindings/mtd/gpmc-nand.txt | 147 ------------------ .../devicetree/bindings/mtd/ti,gpmc-nand.yaml | 121 ++++++++++++++ 2 files changed, 121 insertions(+), 147 deletions(-) delete mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nand.txt create mode 100644 Documentation/devicetree/bindings/mtd/ti,gpmc-nand.yaml diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt deleted file mode 100644 index c459f169a904..000000000000 --- a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt +++ /dev/null @@ -1,147 +0,0 @@ -Device tree bindings for GPMC connected NANDs - -GPMC connected NAND (found on OMAP boards) are represented as child nodes of -the GPMC controller with a name of "nand". - -All timing relevant properties as well as generic gpmc child properties are -explained in a separate documents - please refer to -Documentation/devicetree/bindings/memory-controllers/omap-gpmc.txt - -For NAND specific properties such as ECC modes or bus width, please refer to -Documentation/devicetree/bindings/mtd/nand-controller.yaml - - -Required properties: - - - compatible: "ti,omap2-nand" - - reg: range id (CS number), base offset and length of the - NAND I/O space - - interrupts: Two interrupt specifiers, one for fifoevent, one for termcount. - -Optional properties: - - - nand-bus-width: Set this numeric value to 16 if the hardware - is wired that way. If not specified, a bus - width of 8 is assumed. - - - ti,nand-ecc-opt: A string setting the ECC layout to use. One of: - "sw" 1-bit Hamming ecc code via software - "hw" use "ham1" instead - "hw-romcode" use "ham1" instead - "ham1" 1-bit Hamming ecc code - "bch4" 4-bit BCH ecc code - "bch8" 8-bit BCH ecc code - "bch16" 16-bit BCH ECC code - Refer below "How to select correct ECC scheme for your device ?" - - - ti,nand-xfer-type: A string setting the data transfer type. One of: - - "prefetch-polled" Prefetch polled mode (default) - "polled" Polled mode, without prefetch - "prefetch-dma" Prefetch enabled DMA mode - "prefetch-irq" Prefetch enabled irq mode - - - elm_id: use "ti,elm-id" instead - - ti,elm-id: Specifies phandle of the ELM devicetree node. - ELM is an on-chip hardware engine on TI SoC which is used for - locating ECC errors for BCHx algorithms. SoC devices which have - ELM hardware engines should specify this device node in .dtsi - Using ELM for ECC error correction frees some CPU cycles. - - rb-gpios: GPIO specifier for the ready/busy# pin. - -For inline partition table parsing (optional): - - - #address-cells: should be set to 1 - - #size-cells: should be set to 1 - -Example for an AM33xx board: - - gpmc: gpmc@50000000 { - compatible = "ti,am3352-gpmc"; - ti,hwmods = "gpmc"; - reg = <0x50000000 0x36c>; - interrupts = <100>; - gpmc,num-cs = <8>; - gpmc,num-waitpins = <2>; - #address-cells = <2>; - #size-cells = <1>; - ranges = <0 0 0x08000000 0x1000000>; /* CS0 space, 16MB */ - elm_id = <&elm>; - interrupt-controller; - #interrupt-cells = <2>; - - nand@0,0 { - compatible = "ti,omap2-nand"; - reg = <0 0 4>; /* CS0, offset 0, NAND I/O window 4 */ - interrupt-parent = <&gpmc>; - interrupts = <0 IRQ_TYPE_NONE>, <1 IRQ_TYPE NONE>; - nand-bus-width = <16>; - ti,nand-ecc-opt = "bch8"; - ti,nand-xfer-type = "polled"; - rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */ - - gpmc,sync-clk-ps = <0>; - gpmc,cs-on-ns = <0>; - gpmc,cs-rd-off-ns = <44>; - gpmc,cs-wr-off-ns = <44>; - gpmc,adv-on-ns = <6>; - gpmc,adv-rd-off-ns = <34>; - gpmc,adv-wr-off-ns = <44>; - gpmc,we-off-ns = <40>; - gpmc,oe-off-ns = <54>; - gpmc,access-ns = <64>; - gpmc,rd-cycle-ns = <82>; - gpmc,wr-cycle-ns = <82>; - gpmc,wr-access-ns = <40>; - gpmc,wr-data-mux-bus-ns = <0>; - - #address-cells = <1>; - #size-cells = <1>; - - /* partitions go here */ - }; - }; - -How to select correct ECC scheme for your device ? --------------------------------------------------- -Higher ECC scheme usually means better protection against bit-flips and -increased system lifetime. However, selection of ECC scheme is dependent -on various other factors also like; - -(1) support of built in hardware engines. - Some legacy OMAP SoC do not have ELM harware engine, so those SoC cannot - support ecc-schemes with hardware error-correction (BCHx_HW). However - such SoC can use ecc-schemes with software library for error-correction - (BCHx_HW_DETECTION_SW). The error correction capability with software - library remains equivalent to their hardware counter-part, but there is - slight CPU penalty when too many bit-flips are detected during reads. - -(2) Device parameters like OOBSIZE. - Other factor which governs the selection of ecc-scheme is oob-size. - Higher ECC schemes require more OOB/Spare area to store ECC syndrome, - so the device should have enough free bytes available its OOB/Spare - area to accommodate ECC for entire page. In general following expression - helps in determining if given device can accommodate ECC syndrome: - "2 + (PAGESIZE / 512) * ECC_BYTES" <= OOBSIZE" - where - OOBSIZE number of bytes in OOB/spare area - PAGESIZE number of bytes in main-area of device page - ECC_BYTES number of ECC bytes generated to protect - 512 bytes of data, which is: - '3' for HAM1_xx ecc schemes - '7' for BCH4_xx ecc schemes - '14' for BCH8_xx ecc schemes - '26' for BCH16_xx ecc schemes - - Example(a): For a device with PAGESIZE = 2048 and OOBSIZE = 64 and - trying to use BCH16 (ECC_BYTES=26) ecc-scheme. - Number of ECC bytes per page = (2 + (2048 / 512) * 26) = 106 B - which is greater than capacity of NAND device (OOBSIZE=64) - Hence, BCH16 cannot be supported on given device. But it can - probably use lower ecc-schemes like BCH8. - - Example(b): For a device with PAGESIZE = 2048 and OOBSIZE = 128 and - trying to use BCH16 (ECC_BYTES=26) ecc-scheme. - Number of ECC bytes per page = (2 + (2048 / 512) * 26) = 106 B - which can be accommodated in the OOB/Spare area of this device - (OOBSIZE=128). So this device can use BCH16 ecc-scheme. diff --git a/Documentation/devicetree/bindings/mtd/ti,gpmc-nand.yaml b/Documentation/devicetree/bindings/mtd/ti,gpmc-nand.yaml new file mode 100644 index 000000000000..beb26b9bcfb2 --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/ti,gpmc-nand.yaml @@ -0,0 +1,121 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/mtd/ti,gpmc-nand.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Texas Instruments GPMC NAND Flash controller. + +maintainers: + - Tony Lindgren + - Roger Quadros + +description: + GPMC NAND controller/Flash is represented as a child of the + GPMC controller node. + +properties: + compatible: + const: ti,omap2-nand + + reg: + maxItems: 1 + + interrupts: + items: + - description: Interrupt for fifoevent + - description: Interrupt for termcount + + "#address-cells": true + + "#size-cells": true + + ti,nand-ecc-opt: + description: Desired ECC algorithm + $ref: /schemas/types.yaml#/definitions/string + enum: [sw, ham1, bch4, bch8, bch16] + + ti,nand-xfer-type: + description: Data transfer method between controller and chip. + $ref: /schemas/types.yaml#/definitions/string + enum: [prefetch-polled, polled, prefetch-dma, prefetch-irq] + default: prefetch-polled + + ti,elm-id: + description: + phandle to the ELM (Error Location Module). + $ref: /schemas/types.yaml#/definitions/phandle + + nand-bus-width: + description: + Bus width to the NAND chip + $ref: /schemas/types.yaml#/definitions/uint32 + enum: [8, 16] + default: 8 + +patternProperties: + "@[0-9a-f]+$": + $ref: "/schemas/mtd/partitions/partition.yaml" + +allOf: + - $ref: "/schemas/memory-controllers/ti,gpmc-child.yaml" + +required: + - compatible + - reg + - ti,nand-ecc-opt + +unevaluatedProperties: false + +examples: + - | + #include + #include + + gpmc: memory-controller@50000000 { + compatible = "ti,am3352-gpmc"; + dmas = <&edma 52 0>; + dma-names = "rxtx"; + clocks = <&l3s_gclk>; + clock-names = "fck"; + reg = <0x50000000 0x2000>; + interrupts = ; + gpmc,num-cs = <7>; + gpmc,num-waitpins = <2>; + #address-cells = <2>; + #size-cells = <1>; + interrupt-controller; + #interrupt-cells = <2>; + gpio-controller; + #gpio-cells = <2>; + + ranges = <0 0 0x08000000 0x01000000>; /* CS0 space. Min partition = 16MB */ + nand@0,0 { + compatible = "ti,omap2-nand"; + reg = <0 0 4>; /* device IO registers */ + interrupt-parent = <&gpmc>; + interrupts = <0 IRQ_TYPE_NONE>, /* fifoevent */ + <1 IRQ_TYPE_NONE>; /* termcount */ + ti,nand-xfer-type = "prefetch-dma"; + ti,nand-ecc-opt = "bch16"; + ti,elm-id = <&elm>; + #address-cells = <1>; + #size-cells = <1>; + + /* NAND generic properties */ + nand-bus-width = <8>; + rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */ + + /* GPMC properties*/ + gpmc,device-width = <1>; + + partition@0 { + label = "NAND.SPL"; + reg = <0x00000000 0x00040000>; + }; + partition@1 { + label = "NAND.SPL.backup1"; + reg = <0x00040000 0x00040000>; + }; + }; + }; -- 2.17.1 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/