linux-kernel - [PATCH] i2c: tegra: Wait for config load atomically while in ISR

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Date:   Mon, 11 Jan 2021 15:55:47 +0200
From:   Mikko Perttunen <mperttunen@...dia.com>
To:     ldewangan@...dia.com, digetx@...il.com, thierry.reding@...il.com,
        jonathanh@...dia.com, wsa@...nel.org
Cc:     linux-i2c@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Mikko Perttunen <mperttunen@...dia.com>, stable@...r.kernel.org
Subject: [PATCH] i2c: tegra: Wait for config load atomically while in ISR

Upon a communication error, the interrupt handler can call
tegra_i2c_disable_packet_mode. This causes a sleeping poll to happen
unless the current transaction was marked atomic. Since
tegra_i2c_disable_packet_mode is only called from the interrupt path,
make it use atomic waiting always.

Fixes: ede2299f7101 ("i2c: tegra: Support atomic transfers")
Cc: stable@...r.kernel.org
Signed-off-by: Mikko Perttunen <mperttunen@...dia.com>
---
This fixes constant spew for me while HDMI is connected to a
powered off television.

 drivers/i2c/busses/i2c-tegra.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 6f08c0c3238d..4a7ff1840565 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -528,12 +528,12 @@ static void tegra_i2c_vi_init(struct tegra_i2c_dev *i2c_dev)
 
 static int tegra_i2c_poll_register(struct tegra_i2c_dev *i2c_dev,
 				   u32 reg, u32 mask, u32 delay_us,
-				   u32 timeout_us)
+				   u32 timeout_us, bool force_atomic)
 {
 	void __iomem *addr = i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg);
 	u32 val;
 
-	if (!i2c_dev->atomic_mode)
+	if (!i2c_dev->atomic_mode && !force_atomic)
 		return readl_relaxed_poll_timeout(addr, val, !(val & mask),
 						  delay_us, timeout_us);
 
@@ -560,7 +560,7 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 	val |= mask;
 	i2c_writel(i2c_dev, val, offset);
 
-	err = tegra_i2c_poll_register(i2c_dev, offset, mask, 1000, 1000000);
+	err = tegra_i2c_poll_register(i2c_dev, offset, mask, 1000, 1000000, false);
 	if (err) {
 		dev_err(i2c_dev->dev, "failed to flush FIFO\n");
 		return err;
@@ -569,7 +569,7 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 	return 0;
 }
 
-static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
+static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev, bool force_atomic)
 {
 	int err;
 
@@ -579,7 +579,7 @@ static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
 	i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
 
 	err = tegra_i2c_poll_register(i2c_dev, I2C_CONFIG_LOAD, 0xffffffff,
-				      1000, I2C_CONFIG_LOAD_TIMEOUT);
+				      1000, I2C_CONFIG_LOAD_TIMEOUT, force_atomic);
 	if (err) {
 		dev_err(i2c_dev->dev, "failed to load config\n");
 		return err;
@@ -684,7 +684,7 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 	if (i2c_dev->multimaster_mode && i2c_dev->hw->has_slcg_override_reg)
 		i2c_writel(i2c_dev, I2C_MST_CORE_CLKEN_OVR, I2C_CLKEN_OVERRIDE);
 
-	err = tegra_i2c_wait_for_config_load(i2c_dev);
+	err = tegra_i2c_wait_for_config_load(i2c_dev, false);
 	if (err)
 		return err;
 
@@ -707,7 +707,7 @@ static int tegra_i2c_disable_packet_mode(struct tegra_i2c_dev *i2c_dev)
 	if (cnfg & I2C_CNFG_PACKET_MODE_EN)
 		i2c_writel(i2c_dev, cnfg & ~I2C_CNFG_PACKET_MODE_EN, I2C_CNFG);
 
-	return tegra_i2c_wait_for_config_load(i2c_dev);
+	return tegra_i2c_wait_for_config_load(i2c_dev, true);
 }
 
 static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
@@ -1090,7 +1090,7 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
 	      I2C_BC_TERMINATE;
 	i2c_writel(i2c_dev, val, I2C_BUS_CLEAR_CNFG);
 
-	err = tegra_i2c_wait_for_config_load(i2c_dev);
+	err = tegra_i2c_wait_for_config_load(i2c_dev, false);
 	if (err)
 		return err;
 
-- 
2.30.0