From patchwork Fri May 22 12:45:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pratyush Yadav X-Patchwork-Id: 1296251 X-Patchwork-Delegate: jagannadh.teki@gmail.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.denx.de (client-ip=2a01:238:438b:c500:173d:9f52:ddab:ee01; helo=phobos.denx.de; envelope-from=u-boot-bounces@lists.denx.de; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=ti.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=ti.com header.i=@ti.com header.a=rsa-sha256 header.s=ti-com-17Q1 header.b=x0pbvziC; dkim-atps=neutral Received: from phobos.denx.de (phobos.denx.de [IPv6:2a01:238:438b:c500:173d:9f52:ddab:ee01]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 49T5sP0Z5vz9sRW for ; Fri, 22 May 2020 22:49:12 +1000 (AEST) Received: from h2850616.stratoserver.net (localhost [IPv6:::1]) by phobos.denx.de (Postfix) with ESMTP id 8EB2581E12; Fri, 22 May 2020 14:47:00 +0200 (CEST) Authentication-Results: phobos.denx.de; dmarc=pass (p=quarantine dis=none) header.from=ti.com Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=u-boot-bounces@lists.denx.de Authentication-Results: phobos.denx.de; dkim=pass (1024-bit key; unprotected) header.d=ti.com header.i=@ti.com header.b="x0pbvziC"; dkim-atps=neutral Received: by phobos.denx.de (Postfix, from userid 109) id 2B79D81904; Fri, 22 May 2020 14:45:59 +0200 (CEST) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on phobos.denx.de X-Spam-Level: X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,SPF_HELO_NONE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from fllv0016.ext.ti.com (fllv0016.ext.ti.com [198.47.19.142]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by phobos.denx.de (Postfix) with ESMTPS id 9B9A181866 for ; Fri, 22 May 2020 14:45:54 +0200 (CEST) Authentication-Results: phobos.denx.de; dmarc=pass (p=quarantine dis=none) header.from=ti.com Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=p.yadav@ti.com Received: from lelv0265.itg.ti.com ([10.180.67.224]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 04MCjraO075581; Fri, 22 May 2020 07:45:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1590151553; bh=68aGdyyW+L1ZC4AIgI7CVEPlA2L/LqRJGDR/fSHOAVc=; h=From:To:CC:Subject:Date:In-Reply-To:References; b=x0pbvziCbFYtUHr0ZA8jEsIPFrrUPfEK2TI7spW9KE4GowGGE/X9RQtvrHyfNsyKk XyFPez6mtAylD/FNlk9qLrKvcI6gjKMLXr+5bcuuOg12LvZkNXpoeuhCtiOI8d9vrH C3fxaIOjeE9oGOOdL9ADvQw/owsmZd2bS8jdaBE4= Received: from DFLE113.ent.ti.com (dfle113.ent.ti.com [10.64.6.34]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 04MCjqLN020439 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 22 May 2020 07:45:53 -0500 Received: from DFLE105.ent.ti.com (10.64.6.26) by DFLE113.ent.ti.com (10.64.6.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Fri, 22 May 2020 07:45:52 -0500 Received: from lelv0327.itg.ti.com (10.180.67.183) by DFLE105.ent.ti.com (10.64.6.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3 via Frontend Transport; Fri, 22 May 2020 07:45:52 -0500 Received: from pratyush-OptiPlex-790.dhcp.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id 04MCjAoc091145; Fri, 22 May 2020 07:45:51 -0500 From: Pratyush Yadav To: Jagan Teki , Vignesh Raghavendra CC: Pratyush Yadav , , Sekhar Nori , Pragnesh Patel Subject: [PATCH v4 18/20] mtd: spi-nor-core: Perform a Soft Reset on boot Date: Fri, 22 May 2020 18:15:07 +0530 Message-ID: <20200522124509.6901-19-p.yadav@ti.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200522124509.6901-1-p.yadav@ti.com> References: <20200522124509.6901-1-p.yadav@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.30rc1 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: u-boot-bounces@lists.denx.de Sender: "U-Boot" X-Virus-Scanned: clamav-milter 0.102.2 at phobos.denx.de X-Virus-Status: Clean When the flash is handed to us in a stateful mode like 8D-8D-8D, it is difficult to detect the mode the flash is in. One option is to read SFDP in all modes and see which one gives the correct "SFDP" signature, but not all flashes support SFDP in 8D-8D-8D mode. Further, even if you detect the mode of the flash via SFDP, you still have the problem of actually reading the ID. The Read ID command is not standardized across flash vendors. Flashes can have different dummy cycles needed for reading the ID. Some flashes even expect a 4-byte dummy address with the Read ID command. All this information cannot be obtained from the SFDP table. So, perform a Software Reset sequence before reading the ID and initializing the flash. A Soft Reset will bring back the flash in its default protocol mode assuming no non-volatile configuration was set. This will let us detect the flash even if ROM hands it to us in Octal DTR mode. To accommodate cases where there is more than one flash on a board, and only one of them needs a soft reset, failure to reset is not made fatal, and we still try to read ID if possible. Signed-off-by: Pratyush Yadav --- drivers/mtd/spi/Kconfig | 11 +++++++++++ drivers/mtd/spi/spi-nor-core.c | 27 +++++++++++++++++++++++++++ 2 files changed, 38 insertions(+) diff --git a/drivers/mtd/spi/Kconfig b/drivers/mtd/spi/Kconfig index 018e8c597e..38d509c568 100644 --- a/drivers/mtd/spi/Kconfig +++ b/drivers/mtd/spi/Kconfig @@ -88,6 +88,17 @@ config SPI_FLASH_SFDP_SUPPORT SPI NOR flashes using Serial Flash Discoverable Parameters (SFDP) tables as per JESD216 standard. +config SPI_FLASH_SOFT_RESET + bool "Software Reset support for SPI NOR flashes" + help + Enable support for xSPI Software Reset. It will be used to switch + from Octal DTR mode to legacy mode to allow detecting flashes that + are handed to us in Octal DTR mode. It is expected that if the config + is enabled the flash supports the Soft Reset sequence and is booted in + Octal DTR mode. Do not enable this config on flashes that are not + supposed to be handed to U-Boot in Octal DTR mode, even if they _do_ + support the Soft Reset sequence. + config SPI_FLASH_BAR bool "SPI flash Bank/Extended address register support" help diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c index ca445d7278..4953ea38e8 100644 --- a/drivers/mtd/spi/spi-nor-core.c +++ b/drivers/mtd/spi/spi-nor-core.c @@ -2971,6 +2971,33 @@ int spi_nor_scan(struct spi_nor *nor) nor->setup = spi_nor_default_setup; +#if defined(CONFIG_SPI_FLASH_SOFT_RESET) + /* + * When the flash is handed to us in a stateful mode like 8D-8D-8D, it + * is difficult to detect the mode the flash is in. One option is to + * read SFDP in all modes and see which one gives the correct "SFDP" + * signature, but not all flashes support SFDP in 8D-8D-8D mode. + * + * Further, even if you detect the mode of the flash via SFDP, you + * still have the problem of actually reading the ID. The Read ID + * command is not standardized across flash vendors. Flashes can have + * different dummy cycles needed for reading the ID. Some flashes even + * expect a 4-byte dummy address with the Read ID command. All this + * information cannot be obtained from the SFDP table. + * + * So, perform a Software Reset sequence before reading the ID and + * initializing the flash. A Soft Reset will bring back the flash in + * its default protocol mode assuming no non-volatile configuration was + * set. This will let us detect the flash even if ROM hands it to us in + * Octal DTR mode. + * + * To accommodate cases where there is more than one flash on a board, + * and only one of them needs a soft reset, failure to reset is not + * made fatal, and we still try to read ID if possible. + */ + spi_nor_soft_reset(nor); +#endif /* CONFIG_SPI_FLASH_SOFT_RESET */ + info = spi_nor_read_id(nor); if (IS_ERR_OR_NULL(info)) return -ENOENT;