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[91.76.170.54]) by smtp.googlemail.com with ESMTPSA id e8sm656086lfc.27.2019.06.07.12.47.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 07 Jun 2019 12:48:00 -0700 (PDT) Subject: Re: [PATCH V2 6/6] i2c: tegra: remove BUG, BUG_ON To: Bitan Biswas , Laxman Dewangan , Thierry Reding , Jonathan Hunter , linux-i2c@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Rosin , Wolfram Sang Cc: Shardar Mohammed , Sowjanya Komatineni , Mantravadi Karthik References: <1559935826-25812-1-git-send-email-bbiswas@nvidia.com> <1559935826-25812-6-git-send-email-bbiswas@nvidia.com> From: Dmitry Osipenko Message-ID: Date: Fri, 7 Jun 2019 22:47:59 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <1559935826-25812-6-git-send-email-bbiswas@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 07.06.2019 22:30, Bitan Biswas пишет: > Remove redundant BUG_ON calls or replace with WARN_ON_ONCE > as needed. Replace BUG() with error handling code. > Define I2C_ERR_UNEXPECTED_STATUS for error handling. > > Signed-off-by: Bitan Biswas > --- > drivers/i2c/busses/i2c-tegra.c | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c > index 4dfb4c1..c89d0ee 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_UNEXPECTED_STATUS BIT(3) > > #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28 > #define PACKET_HEADER0_PACKET_ID_SHIFT 16 > @@ -515,7 +516,6 @@ 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); > val = i2c_readl(i2c_dev, I2C_RX_FIFO); > val = cpu_to_le32(val); > memcpy(buf, &val, buf_remaining); > @@ -523,7 +523,6 @@ 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); > i2c_dev->msg_buf_remaining = buf_remaining; > i2c_dev->msg_buf = buf; > > @@ -581,7 +580,6 @@ 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); > memcpy(&val, buf, buf_remaining); > val = le32_to_cpu(val); > > @@ -847,10 +845,13 @@ 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) > + if (i2c_dev->msg_buf_remaining) { > tegra_i2c_empty_rx_fifo(i2c_dev); > - else > - BUG(); > + } else { > + dev_err(i2c_dev->dev, "unexpected rx data request\n"); > + i2c_dev->msg_err |= I2C_ERR_UNEXPECTED_STATUS; > + goto err; > + } > } > > if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) { > @@ -876,7 +877,8 @@ 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); > + if (WARN_ON_ONCE(i2c_dev->msg_buf_remaining)) > + goto err; > complete(&i2c_dev->msg_complete); > } > goto done; > Unfortunately that's not enough because the indicator of the error is the i2c_dev->msg_err and no error is set in yours case, hence no hardware reset will be performed. It should be at least somewhat like this: if (WARN_ON_ONCE(i2c_dev->msg_buf_remaining)) { i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT; goto err; }