From patchwork Mon Mar 3 11:19:20 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: pekon gupta X-Patchwork-Id: 325787 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from casper.infradead.org (unknown [IPv6:2001:770:15f::2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 126FC2C0142 for ; Mon, 3 Mar 2014 22:20:20 +1100 (EST) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WKQuq-0004E9-JZ; Mon, 03 Mar 2014 11:20:12 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WKQuo-00045D-SP; Mon, 03 Mar 2014 11:20:10 +0000 Received: from devils.ext.ti.com ([198.47.26.153]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WKQul-00043X-FF for linux-mtd@lists.infradead.org; Mon, 03 Mar 2014 11:20:09 +0000 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by devils.ext.ti.com (8.13.7/8.13.7) with ESMTP id s23BJe7K019936; Mon, 3 Mar 2014 05:19:40 -0600 Received: from DLEE70.ent.ti.com (dlee70.ent.ti.com [157.170.170.113]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id s23BJeaN029337; Mon, 3 Mar 2014 05:19:40 -0600 Received: from dlep33.itg.ti.com (157.170.170.75) by DLEE70.ent.ti.com (157.170.170.113) with Microsoft SMTP Server id 14.3.174.1; Mon, 3 Mar 2014 05:19:40 -0600 Received: from psplinux063.india.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dlep33.itg.ti.com (8.14.3/8.13.8) with ESMTP id s23BJZC6003333; Mon, 3 Mar 2014 05:19:38 -0600 From: Pekon Gupta To: Brian Norris Subject: [PATCH v5 1/4] mtd: devices: elm: check for hardware engine's design constrains Date: Mon, 3 Mar 2014 16:49:20 +0530 Message-ID: <1393845563-7800-2-git-send-email-pekon@ti.com> X-Mailer: git-send-email 1.8.5.1.163.gd7aced9 In-Reply-To: <1393845563-7800-1-git-send-email-pekon@ti.com> References: <1393845563-7800-1-git-send-email-pekon@ti.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140303_062007_654902_A9595CB3 X-CRM114-Status: GOOD ( 14.90 ) X-Spam-Score: -6.9 (------) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-6.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [198.47.26.153 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Stefan Roese , linux-mtd , Felipe Balbi , Ezequiel Garcia , Pekon Gupta X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org ELM hardware engine is used by BCH ecc-schemes for detecting and locating ECC errors. This patch adds following checks as per ELM design constrains: - ELM internal buffers are of 1K, So it cannot process data with ecc-step-size > 1K. - ELM engine can execute upto maximum of 8 threads in parallel, So in *page-mode* (when complete page is processed in single iteration), ELM cannot support ecc-steps > 8. Signed-off-by: Pekon Gupta --- drivers/mtd/devices/elm.c | 19 ++++++++++++++++++- drivers/mtd/nand/omap2.c | 9 ++++++--- include/linux/platform_data/elm.h | 3 ++- 3 files changed, 26 insertions(+), 5 deletions(-) diff --git a/drivers/mtd/devices/elm.c b/drivers/mtd/devices/elm.c index f160d2c..7fda50f 100644 --- a/drivers/mtd/devices/elm.c +++ b/drivers/mtd/devices/elm.c @@ -84,6 +84,9 @@ struct elm_info { struct list_head list; enum bch_ecc bch_type; struct elm_registers elm_regs; + int ecc_steps; + int ecc_step_size; + int ecc_step_bytes; }; static LIST_HEAD(elm_devices); @@ -103,7 +106,8 @@ static u32 elm_read_reg(struct elm_info *info, int offset) * @dev: ELM device * @bch_type: Type of BCH ecc */ -int elm_config(struct device *dev, enum bch_ecc bch_type) +int elm_config(struct device *dev, enum bch_ecc bch_type, + int ecc_steps, int ecc_step_size, int ecc_step_bytes) { u32 reg_val; struct elm_info *info = dev_get_drvdata(dev); @@ -112,10 +116,23 @@ int elm_config(struct device *dev, enum bch_ecc bch_type) dev_err(dev, "Unable to configure elm - device not probed?\n"); return -ENODEV; } + /* ELM cannot detect ECC errors for chunks > 1KB */ + if (ecc_step_size > (ELM_ECC_SIZE/2 + 1)) { + pr_err("unsupported config ecc-size=%d", ecc_step_size); + return -EINVAL; + } + /* ELM support 8 error syndrome process */ + if (ecc_steps > ERROR_VECTOR_MAX) { + pr_err("unsupported config ecc-step=%d", ecc_steps); + return -EINVAL; + } reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16); elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val); info->bch_type = bch_type; + info->ecc_steps = ecc_steps; + info->ecc_step_size = ecc_step_size; + info->ecc_step_bytes = ecc_step_bytes; return 0; } diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index 5ce2097..369aee7 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -1546,6 +1546,8 @@ static int is_elm_present(struct omap_nand_info *info, struct device_node *elm_node, enum bch_ecc bch_type) { struct platform_device *pdev; + struct nand_ecc_ctrl *ecc = &info->nand.ecc; + int err = 0; /* check whether elm-id is passed via DT */ if (!elm_node) { pr_err("nand: error: ELM DT node not found\n"); @@ -1559,9 +1561,10 @@ static int is_elm_present(struct omap_nand_info *info, } /* ELM module available, now configure it */ info->elm_dev = &pdev->dev; - if (elm_config(info->elm_dev, bch_type)) - return -ENODEV; - return 0; + err = elm_config(info->elm_dev, bch_type, + (info->mtd.writesize / ecc->size), ecc->size, ecc->bytes); + + return err; } #endif /* CONFIG_MTD_NAND_ECC_BCH */ diff --git a/include/linux/platform_data/elm.h b/include/linux/platform_data/elm.h index bf0a83b..b824ff3 100644 --- a/include/linux/platform_data/elm.h +++ b/include/linux/platform_data/elm.h @@ -50,5 +50,6 @@ struct elm_errorvec { void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc, struct elm_errorvec *err_vec); -int elm_config(struct device *dev, enum bch_ecc bch_type); +int elm_config(struct device *dev, enum bch_ecc bch_type, + int ecc_steps, int ecc_step_size, int ecc_step_bytes); #endif /* __ELM_H */