linux-kernel - [PATCH v6 21/35] i2c: tegra: Don't fall back to PIO mode if DMA configuration fails

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200908021021.9123-22-digetx@gmail.com>
Date:   Tue,  8 Sep 2020 05:10:07 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     linux-i2c@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v6 21/35] i2c: tegra: Don't fall back to PIO mode if DMA configuration fails

The DMA code path has been tested well enough and the DMA configuration
performed by tegra_i2c_config_fifo_trig() shouldn't ever fail in practice.
Hence let's remove the obscure transfer-mode switching in order to have a
cleaner and simpler code. Now I2C transfer will be failed if DMA
configuration fails.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/i2c/busses/i2c-tegra.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index e94da14d36e2..ba71b64e5e64 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -940,8 +940,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
-				       size_t len)
+static int tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev, size_t len)
 {
 	u32 val, reg;
 	u8 dma_burst;
@@ -992,12 +991,10 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
 		if (ret < 0) {
 			dev_err(i2c_dev->dev, "DMA slave config failed: %d\n",
 				ret);
-			dev_err(i2c_dev->dev, "falling back to PIO\n");
-			tegra_i2c_release_dma(i2c_dev);
-			i2c_dev->is_curr_dma_xfer = false;
-		} else {
-			goto out;
+			return ret;
 		}
+
+		goto out;
 	}
 
 	if (i2c_dev->hw->has_mst_fifo)
@@ -1008,6 +1005,8 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
 		      I2C_FIFO_CONTROL_RX_TRIG(1);
 out:
 	i2c_writel(i2c_dev, val, reg);
+
+	return 0;
 }
 
 static unsigned long
@@ -1141,7 +1140,10 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 	i2c_dev->is_curr_dma_xfer = (xfer_size > I2C_PIO_MODE_PREFERRED_LEN) &&
 				    i2c_dev->dma_buf &&
 				    !i2c_dev->is_curr_atomic_xfer;
-	tegra_i2c_config_fifo_trig(i2c_dev, xfer_size);
+
+	err = tegra_i2c_config_fifo_trig(i2c_dev, xfer_size);
+	if (err)
+		return err;
 
 	/*
 	 * Transfer time in mSec = Total bits / transfer rate
-- 
2.27.0