From patchwork Wed Nov 23 21:17:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Barrett-Morrison X-Patchwork-Id: 628252 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BD09C433FE for ; Wed, 23 Nov 2022 21:17:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229563AbiKWVRU (ORCPT ); Wed, 23 Nov 2022 16:17:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235918AbiKWVRM (ORCPT ); Wed, 23 Nov 2022 16:17:12 -0500 Received: from mail-qt1-x82d.google.com (mail-qt1-x82d.google.com [IPv6:2607:f8b0:4864:20::82d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 958A9A314F for ; Wed, 23 Nov 2022 13:17:09 -0800 (PST) Received: by mail-qt1-x82d.google.com with SMTP id l2so8530qtq.11 for ; Wed, 23 Nov 2022 13:17:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=timesys-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=4aqA0Mj3WFRM9SvHIljdHQ8+p96l5z6GhwHZgBiTLAE=; b=HOfGOF/KzrNbTIEs25w7CIh7DweUpRjCaPuDjlosBtlXKTk5QqFEzt3NJlVaE74iA+ jA7UAv8BMJsiduZ2LNB6LjS1SQ3WuyoMibpm7eolcRqsiqLLvyhUKhSNeEF4sUsGESwh n+QZCA9GvgGW7ATurAKm+W2fnWmcLbPdkaWDw+LVsC2p4hEzmgOAnczFW9efTzBhqi9w pGreWtPd65aM7ysQ+zIW0zT8Giv73OPlqvwvs64u+gAwgRbZ59rlJq3oQfikHxObzYjT LRppuKzblg5+Qk6uqK2hM6hItqAFhcw94hgYsYMjILCR13DJUb7ZnTQsRERX5hOSc2Gn xsQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=4aqA0Mj3WFRM9SvHIljdHQ8+p96l5z6GhwHZgBiTLAE=; b=TMyW8NJ7MrZDcrpxcT/0FxQej324PUB3WS5aOvoGcmFAWZCltIsnOg4NhFLWyr0RQq Gp8PFk4/QSfPAKTiAs0LCc6yVUb9JYKvLsWzk8IOm/4w1qoaWRWM2xT8cV/DaHZPPEjL 22C5kJjHVGfNfroBvaShhFucOil/LmzGbNDHy8XH21dCvcw1canSHunYa7pSr61EcyKc Wz3J9zZWWfk19la7c77FsJ8ufWd1NB+mFtq1BmphT9A5C1s2BCSsY+PbdovCYrARzpXW aCmvdAHu2grwQ+YYhEFDjUxmhSmH1FXfUkx2itZINl6CfhxkijQPddcSu9WvQw/t2tpb 8NbA== X-Gm-Message-State: ANoB5pnrsZqpiGkfot0Hw5HpZN3grVtEZSPv0r0M1ldqaG9LNN/BuLYE h1GYAjcE2K0/awBcoK3mHvGztGBiTuBm4BWc X-Google-Smtp-Source: AA0mqf4OXplR5mPC7T71BzFi9Tan1aVm5pq33+5u3HIsJmIGGOTjUuPwUlTFhECijGg6dxTzh4uCpA== X-Received: by 2002:ac8:4d4f:0:b0:3a6:1dea:8c1c with SMTP id x15-20020ac84d4f000000b003a61dea8c1cmr18403042qtv.157.1669238228695; Wed, 23 Nov 2022 13:17:08 -0800 (PST) Received: from nathan-ideapad.. (d-75-76-18-234.oh.cpe.breezeline.net. [75.76.18.234]) by smtp.gmail.com with ESMTPSA id o22-20020ac872d6000000b00399edda03dfsm10203066qtp.67.2022.11.23.13.17.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Nov 2022 13:17:08 -0800 (PST) From: Nathan Barrett-Morrison Cc: nathan.morrison@timesys.com, greg.malysa@timesys.com, Mark Brown , linux-spi@vger.kernel.org (open list:SPI SUBSYSTEM), linux-kernel@vger.kernel.org (open list) Subject: [PATCH] spi: cadence-quadspi: Add upper limit safety check to baudrate divisor Date: Wed, 23 Nov 2022 16:17:05 -0500 Message-Id: <20221123211705.126900-1-nathan.morrison@timesys.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org While bringing up the cadence-quadspi driver on a customer board, I discovered that the baud divisor calculation can exceed the peripheral's maximum in some circumstances. This will prevent it. Signed-off-by: Nathan Barrett-Morrison --- drivers/spi/spi-cadence-quadspi.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c index 447230547945..250575fb7b0e 100644 --- a/drivers/spi/spi-cadence-quadspi.c +++ b/drivers/spi/spi-cadence-quadspi.c @@ -1119,6 +1119,10 @@ static void cqspi_config_baudrate_div(struct cqspi_st *cqspi) /* Recalculate the baudrate divisor based on QSPI specification. */ div = DIV_ROUND_UP(ref_clk_hz, 2 * cqspi->sclk) - 1; + /* Maximum baud divisor */ + if (div > CQSPI_REG_CONFIG_BAUD_MASK) + div = CQSPI_REG_CONFIG_BAUD_MASK; + reg = readl(reg_base + CQSPI_REG_CONFIG); reg &= ~(CQSPI_REG_CONFIG_BAUD_MASK << CQSPI_REG_CONFIG_BAUD_LSB); reg |= (div & CQSPI_REG_CONFIG_BAUD_MASK) << CQSPI_REG_CONFIG_BAUD_LSB;