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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E18FFC432C0 for ; Tue, 19 Nov 2019 05:57:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AE8B72084D for ; Tue, 19 Nov 2019 05:57:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574143032; bh=SgPrO7ugVJyhINURkWlDfRVDXn1Vdmrw7OE7L8HeNAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lVulfFOSLrkHqzQtXTk7nv/Uroic5wiaS4WDXOO718qqwxG104mD2gAT7pjODBIH5 YFyqNCJUABvpwpeG8yhABgpy294dYFjh+4/FfnvGmj2qySsjMpNl2SDmuInp0ZtyXc P9iHnzez1CJjISc4uAlxYyXkL6r0MqKL6PxFf4Fg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731586AbfKSFw0 (ORCPT ); Tue, 19 Nov 2019 00:52:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:50054 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731891AbfKSFwW (ORCPT ); Tue, 19 Nov 2019 00:52:22 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7BBFB20862; Tue, 19 Nov 2019 05:52:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574142741; bh=SgPrO7ugVJyhINURkWlDfRVDXn1Vdmrw7OE7L8HeNAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mP8qMuiOfte6Axn+2UmhBQE642GEVDpm63Z370l/sszuT0o9beTQks9jevDUNyQ2S NZRMbgmCzWHpfaPi708J06Pyk9rChnNmO5oJuwt8L9Fal5mXWlq31P9ea3/MZ+wbH4 i9MbxWz1gI2LAMxbhP1J5J5NoMHPqIZAEpY4p0EQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Brendan Higgins , Jae Hyun Yoo , Wolfram Sang , Sasha Levin Subject: [PATCH 4.14 185/239] i2c: aspeed: fix invalid clock parameters for very large divisors Date: Tue, 19 Nov 2019 06:19:45 +0100 Message-Id: <20191119051335.060834185@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191119051255.850204959@linuxfoundation.org> References: <20191119051255.850204959@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Brendan Higgins [ Upstream commit 17ccba67109cd0631f206cf49e17986218b47854 ] The function that computes clock parameters from divisors did not respect the maximum size of the bitfields that the parameters were written to. This fixes the bug. This bug can be reproduced with (and this fix verified with) the test at: https://kunit-review.googlesource.com/c/linux/+/1035/ Discovered-by-KUnit: https://kunit-review.googlesource.com/c/linux/+/1035/ Signed-off-by: Brendan Higgins Reviewed-by: Jae Hyun Yoo Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-aspeed.c | 65 +++++++++++++++++++++++---------- 1 file changed, 45 insertions(+), 20 deletions(-) diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c index a074735456bc7..29574b9075fd7 100644 --- a/drivers/i2c/busses/i2c-aspeed.c +++ b/drivers/i2c/busses/i2c-aspeed.c @@ -135,7 +135,8 @@ struct aspeed_i2c_bus { /* Synchronizes I/O mem access to base. */ spinlock_t lock; struct completion cmd_complete; - u32 (*get_clk_reg_val)(u32 divisor); + u32 (*get_clk_reg_val)(struct device *dev, + u32 divisor); unsigned long parent_clk_frequency; u32 bus_frequency; /* Transaction state. */ @@ -679,16 +680,27 @@ static const struct i2c_algorithm aspeed_i2c_algo = { #endif /* CONFIG_I2C_SLAVE */ }; -static u32 aspeed_i2c_get_clk_reg_val(u32 clk_high_low_max, u32 divisor) +static u32 aspeed_i2c_get_clk_reg_val(struct device *dev, + u32 clk_high_low_mask, + u32 divisor) { - u32 base_clk, clk_high, clk_low, tmp; + u32 base_clk_divisor, clk_high_low_max, clk_high, clk_low, tmp; + + /* + * SCL_high and SCL_low represent a value 1 greater than what is stored + * since a zero divider is meaningless. Thus, the max value each can + * store is every bit set + 1. Since SCL_high and SCL_low are added + * together (see below), the max value of both is the max value of one + * them times two. + */ + clk_high_low_max = (clk_high_low_mask + 1) * 2; /* * The actual clock frequency of SCL is: * SCL_freq = APB_freq / (base_freq * (SCL_high + SCL_low)) * = APB_freq / divisor * where base_freq is a programmable clock divider; its value is - * base_freq = 1 << base_clk + * base_freq = 1 << base_clk_divisor * SCL_high is the number of base_freq clock cycles that SCL stays high * and SCL_low is the number of base_freq clock cycles that SCL stays * low for a period of SCL. @@ -698,47 +710,59 @@ static u32 aspeed_i2c_get_clk_reg_val(u32 clk_high_low_max, u32 divisor) * SCL_low = clk_low + 1 * Thus, * SCL_freq = APB_freq / - * ((1 << base_clk) * (clk_high + 1 + clk_low + 1)) + * ((1 << base_clk_divisor) * (clk_high + 1 + clk_low + 1)) * The documentation recommends clk_high >= clk_high_max / 2 and * clk_low >= clk_low_max / 2 - 1 when possible; this last constraint * gives us the following solution: */ - base_clk = divisor > clk_high_low_max ? + base_clk_divisor = divisor > clk_high_low_max ? ilog2((divisor - 1) / clk_high_low_max) + 1 : 0; - tmp = (divisor + (1 << base_clk) - 1) >> base_clk; - clk_low = tmp / 2; - clk_high = tmp - clk_low; - if (clk_high) - clk_high--; + if (base_clk_divisor > ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) { + base_clk_divisor = ASPEED_I2CD_TIME_BASE_DIVISOR_MASK; + clk_low = clk_high_low_mask; + clk_high = clk_high_low_mask; + dev_err(dev, + "clamping clock divider: divider requested, %u, is greater than largest possible divider, %u.\n", + divisor, (1 << base_clk_divisor) * clk_high_low_max); + } else { + tmp = (divisor + (1 << base_clk_divisor) - 1) + >> base_clk_divisor; + clk_low = tmp / 2; + clk_high = tmp - clk_low; + + if (clk_high) + clk_high--; - if (clk_low) - clk_low--; + if (clk_low) + clk_low--; + } return ((clk_high << ASPEED_I2CD_TIME_SCL_HIGH_SHIFT) & ASPEED_I2CD_TIME_SCL_HIGH_MASK) | ((clk_low << ASPEED_I2CD_TIME_SCL_LOW_SHIFT) & ASPEED_I2CD_TIME_SCL_LOW_MASK) - | (base_clk & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK); + | (base_clk_divisor + & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK); } -static u32 aspeed_i2c_24xx_get_clk_reg_val(u32 divisor) +static u32 aspeed_i2c_24xx_get_clk_reg_val(struct device *dev, u32 divisor) { /* * clk_high and clk_low are each 3 bits wide, so each can hold a max * value of 8 giving a clk_high_low_max of 16. */ - return aspeed_i2c_get_clk_reg_val(16, divisor); + return aspeed_i2c_get_clk_reg_val(dev, GENMASK(2, 0), divisor); } -static u32 aspeed_i2c_25xx_get_clk_reg_val(u32 divisor) +static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor) { /* * clk_high and clk_low are each 4 bits wide, so each can hold a max * value of 16 giving a clk_high_low_max of 32. */ - return aspeed_i2c_get_clk_reg_val(32, divisor); + return aspeed_i2c_get_clk_reg_val(dev, GENMASK(3, 0), divisor); } /* precondition: bus.lock has been acquired. */ @@ -751,7 +775,7 @@ static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus) clk_reg_val &= (ASPEED_I2CD_TIME_TBUF_MASK | ASPEED_I2CD_TIME_THDSTA_MASK | ASPEED_I2CD_TIME_TACST_MASK); - clk_reg_val |= bus->get_clk_reg_val(divisor); + clk_reg_val |= bus->get_clk_reg_val(bus->dev, divisor); writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1); writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2); @@ -859,7 +883,8 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev) if (!match) bus->get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val; else - bus->get_clk_reg_val = (u32 (*)(u32))match->data; + bus->get_clk_reg_val = (u32 (*)(struct device *, u32)) + match->data; /* Initialize the I2C adapter */ spin_lock_init(&bus->lock); -- 2.20.1