From patchwork Tue Jun 18 11:09:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bitan Biswas X-Patchwork-Id: 1117789 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-tegra-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=nvidia.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=nvidia.com header.i=@nvidia.com header.b="Tw18Jiag"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45SljD6PxZz9sBr for ; Tue, 18 Jun 2019 21:09:52 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729631AbfFRLJv (ORCPT ); Tue, 18 Jun 2019 07:09:51 -0400 Received: from hqemgate14.nvidia.com ([216.228.121.143]:4439 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729458AbfFRLJv (ORCPT ); Tue, 18 Jun 2019 07:09:51 -0400 Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 18 Jun 2019 04:09:49 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Tue, 18 Jun 2019 04:09:49 -0700 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Tue, 18 Jun 2019 04:09:49 -0700 Received: from HQMAIL104.nvidia.com (172.18.146.11) by HQMAIL106.nvidia.com (172.18.146.12) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 18 Jun 2019 11:09:48 +0000 Received: from hqnvemgw01.nvidia.com (172.20.150.20) by HQMAIL104.nvidia.com (172.18.146.11) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Tue, 18 Jun 2019 11:09:48 +0000 Received: from dhcp-10-19-65-14.client.nvidia.com (Not Verified[10.19.65.14]) by hqnvemgw01.nvidia.com with Trustwave SEG (v7, 5, 8, 10121) id ; Tue, 18 Jun 2019 04:09:48 -0700 From: Bitan Biswas To: Laxman Dewangan , Thierry Reding , Jonathan Hunter , , , , Peter Rosin , Wolfram Sang , Dmitry Osipenko CC: Shardar Mohammed , Sowjanya Komatineni , Mantravadi Karthik , Bitan Biswas Subject: [PATCH V9] i2c: tegra: remove BUG() macro Date: Tue, 18 Jun 2019 04:09:42 -0700 Message-ID: <1560856182-26072-1-git-send-email-bbiswas@nvidia.com> X-Mailer: git-send-email 2.7.4 X-NVConfidentiality: public MIME-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1560856189; bh=GlqsET9RW9Zv0z9qf02TmUpqsUQyA8cD5UZ3n51Ox3k=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: X-NVConfidentiality:MIME-Version:Content-Type; b=Tw18JiagS36BQWe3Omn77LgcN0rf9PQRZagZ70q0rtrF1gmPw/fXa1AN021YD7FUw HG3c91yek1g393pkChr+blvZA9/kH2/8h3fA2LxeMFBQ6kIkgyFYWqt3cpe8CqtgfF B/OxefC0A+eoKhEha18nt8pOyw0xMVjgDzUvJ/d3rImLTWUTV9NoB1t4/tYRYqbIe3 BN9TE0G6RDba/6lQsnV/MXvlQXZCXvKG+mGLEwRy6/1edVPSX8SNAOLuDKFSgzqOdT uOao2KBoMkSBiGIzqt7QPHUODbwwgLtpTqpSUmmImUKiua04UN4MabDFPD53dIcGLW hJnfu4RymuYRA== Sender: linux-tegra-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org The usage of BUG() macro is generally discouraged in kernel, unless it's a problem that results in a physical damage or loss of data. This patch removes unnecessary BUG() macros and replaces the rest with warning. Signed-off-by: Bitan Biswas Reviewed-by: Dmitry Osipenko Tested-by: Dmitry Osipenko Acked-by: Thierry Reding --- drivers/i2c/busses/i2c-tegra.c | 47 +++++++++++++++++++++++++++++++++++------- 1 file changed, 39 insertions(+), 8 deletions(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 4dfb4c1..e9ff96d 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -73,6 +73,7 @@ #define I2C_ERR_NO_ACK BIT(0) #define I2C_ERR_ARBITRATION_LOST BIT(1) #define I2C_ERR_UNKNOWN_INTERRUPT BIT(2) +#define I2C_ERR_RX_BUFFER_OVERFLOW BIT(3) #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28 #define PACKET_HEADER0_PACKET_ID_SHIFT 16 @@ -489,6 +490,13 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) size_t buf_remaining = i2c_dev->msg_buf_remaining; int words_to_transfer; + /* + * Catch overflow due to message fully sent + * before the check for RX FIFO availability. + */ + if (WARN_ON_ONCE(!(i2c_dev->msg_buf_remaining))) + return -EINVAL; + if (i2c_dev->hw->has_mst_fifo) { val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS); rx_fifo_avail = (val & I2C_MST_FIFO_STATUS_RX_MASK) >> @@ -515,7 +523,11 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) * prevent overwriting past the end of buf */ if (rx_fifo_avail > 0 && buf_remaining > 0) { - BUG_ON(buf_remaining > 3); + /* + * buf_remaining > 3 check not needed as rx_fifo_avail == 0 + * when (words_to_transfer was > rx_fifo_avail) earlier + * in this function. + */ val = i2c_readl(i2c_dev, I2C_RX_FIFO); val = cpu_to_le32(val); memcpy(buf, &val, buf_remaining); @@ -523,7 +535,10 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) rx_fifo_avail--; } - BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0); + /* RX FIFO must be drained, otherwise it's an Overflow case. */ + if (WARN_ON_ONCE(rx_fifo_avail)) + return -EINVAL; + i2c_dev->msg_buf_remaining = buf_remaining; i2c_dev->msg_buf = buf; @@ -581,7 +596,11 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev) * boundary and fault. */ if (tx_fifo_avail > 0 && buf_remaining > 0) { - BUG_ON(buf_remaining > 3); + /* + * buf_remaining > 3 check not needed as tx_fifo_avail == 0 + * when (words_to_transfer was > tx_fifo_avail) earlier + * in this function for non-zero words_to_transfer. + */ memcpy(&val, buf, buf_remaining); val = le32_to_cpu(val); @@ -847,10 +866,15 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) if (!i2c_dev->is_curr_dma_xfer) { if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) { - if (i2c_dev->msg_buf_remaining) - tegra_i2c_empty_rx_fifo(i2c_dev); - else - BUG(); + if (tegra_i2c_empty_rx_fifo(i2c_dev)) { + /* + * Overflow error condition: message fully sent, + * with no XFER_COMPLETE interrupt but hardware + * asks to transfer more. + */ + i2c_dev->msg_err |= I2C_ERR_RX_BUFFER_OVERFLOW; + goto err; + } } if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) { @@ -876,7 +900,14 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) if (status & I2C_INT_PACKET_XFER_COMPLETE) { if (i2c_dev->is_curr_dma_xfer) i2c_dev->msg_buf_remaining = 0; - BUG_ON(i2c_dev->msg_buf_remaining); + /* + * Underflow error condition: XFER_COMPLETE before message + * fully sent. + */ + if (WARN_ON_ONCE(i2c_dev->msg_buf_remaining)) { + i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT; + goto err; + } complete(&i2c_dev->msg_complete); } goto done;