From patchwork Tue Nov 15 11:49:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dhruva Gole X-Patchwork-Id: 1703988 X-Patchwork-Delegate: jagannadh.teki@gmail.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.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: legolas.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=j2tf0dyJ; 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 ECDSA (P-384) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4NBPd52CXjz23mY for ; Tue, 15 Nov 2022 22:50:33 +1100 (AEDT) Received: from h2850616.stratoserver.net (localhost [IPv6:::1]) by phobos.denx.de (Postfix) with ESMTP id BE7B98503A; Tue, 15 Nov 2022 12:50:19 +0100 (CET) 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="j2tf0dyJ"; dkim-atps=neutral Received: by phobos.denx.de (Postfix, from userid 109) id BA6D480A46; Tue, 15 Nov 2022 12:50:15 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on phobos.denx.de X-Spam-Level: X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.2 Received: from lelv0142.ext.ti.com (lelv0142.ext.ti.com [198.47.23.249]) (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 5E96284FB3 for ; Tue, 15 Nov 2022 12:50:09 +0100 (CET) Authentication-Results: phobos.denx.de; dmarc=pass (p=quarantine dis=none) header.from=ti.com Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=d-gole@ti.com Received: from fllv0035.itg.ti.com ([10.64.41.0]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id 2AFBnwLS027935; Tue, 15 Nov 2022 05:49:58 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1668512998; bh=ml/aKjevl6eu2WfZqg5f3pea0/TCoqvWHHWeR60wDHo=; h=From:To:CC:Subject:Date:In-Reply-To:References; b=j2tf0dyJ3oZhvCKUpIZNMCabTlHvIVzMT+KdfmR4gJLMLAdTtYp6Yv6vL0UPzIGDQ qlVBDDEeybI7DKH2Q/Io+ammq5ck9UWN2ip4nu2gFaCkU9FPziVqO+RE+fgXubuSr/ bCrWzfGB5uYgQGnK2rq7hRJyhhZgezRAD5cnMIe0= Received: from DFLE103.ent.ti.com (dfle103.ent.ti.com [10.64.6.24]) by fllv0035.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 2AFBnwwx109192 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 15 Nov 2022 05:49:58 -0600 Received: from DFLE105.ent.ti.com (10.64.6.26) by DFLE103.ent.ti.com (10.64.6.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.6; Tue, 15 Nov 2022 05:49:58 -0600 Received: from lelv0326.itg.ti.com (10.180.67.84) 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 15.1.2507.6 via Frontend Transport; Tue, 15 Nov 2022 05:49:58 -0600 Received: from localhost (ileaxei01-snat.itg.ti.com [10.180.69.5]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 2AFBnvaA018411; Tue, 15 Nov 2022 05:49:57 -0600 From: Dhruva Gole To: Tom Rini CC: Dhruva Gole , Vignesh , Jagan Teki , , Pratyush Yadav Subject: [PATCH v2 2/2] spi: cadence_qspi: use STIG mode for small reads Date: Tue, 15 Nov 2022 17:19:26 +0530 Message-ID: <20221115114926.174351-2-d-gole@ti.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221115114926.174351-1-d-gole@ti.com> References: <20221115114926.174351-1-d-gole@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: 2.1.39 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 0.103.6 at phobos.denx.de X-Virus-Status: Clean Fix the issue where some flash chips like cypress S25HS256T for example return the value of the same register once a SPI transaction starts. So for example if read reg of 0x2 is requested and we start reading registers in DAC mode we start reading 4 byte aligned ie. 0x0, 0x1, 0x2 and then 0x3. In such a case the flash chip keeps returning the value of 0x0 even though we actually want the value of 0x2. STIG mode solves the above issue by not issuing a read continuosly for 4 byte aligned data. Signed-off-by: Dhruva Gole --- v2: No changes from previous patch. However this DEPENDS on PATCH 1/2 of the same series. Hence disregard the previously sent patch: [PATCH] spi: cadence-qspi: use STIG mode for small reads https://lore.kernel.org/u-boot/20221111110720.283013-1-d-gole@ti.com/T/#u drivers/spi/cadence_qspi.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/spi/cadence_qspi.c b/drivers/spi/cadence_qspi.c index ab0a681c8376..6f2924fe4515 100644 --- a/drivers/spi/cadence_qspi.c +++ b/drivers/spi/cadence_qspi.c @@ -307,7 +307,22 @@ static int cadence_spi_mem_exec_op(struct spi_slave *spi, priv->is_decoded_cs); if (op->data.dir == SPI_MEM_DATA_IN && op->data.buf.in) { - if (!op->addr.nbytes) + /* + * In some cases there is a layer of digital logic in front of the QSPI + * /OSPI Driver when used in DAC mode. This digital logic layer ensures + * that even if we are trying to read 1 or 2 bytes of data, it will + * always align it to 4 bytes from a 4byte aligned address. In some + * flash chips like cypress for example, if we try to read some regs + * in DAC mode then it keeps sending the value of the first register + * who was requested and inorder to read the next register we have to + * stop and re-initiate a new transaction. + * This causes wrong registers values to be read than what is desired + * when registers are read in DAC mode. Hence if the data.nbytes + * is very less then do not use DAC mode. Registers are generally only + * 1-2 bytes and thus switching to STIG mode will be a work around. + */ + if (!op->addr.nbytes || + op->data.nbytes < CQSPI_STIG_DATA_LEN_MAX) mode = CQSPI_STIG_READ; else mode = CQSPI_READ;