Revert "i2c: tegra: Remove the synchronization between isr and caller"

This reverts commit fbe412ed91158bc1ec5c30c1bc9e9857a115d754.
This fixed the video recording system hang bug.

Bug 842901

Change-Id: I9467931ffe57b0d7462f6ca09f7582f9c3c40e46
Reviewed-on: http://git-master/r/39286
Tested-by: Zhijun He <zhhe@nvidia.com>
Reviewed-by: Jeremy Wyman <jwyman@nvidia.com>

1 files changed, 37 insertions, 6 deletions

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index c8a26a85a938..f9a14a75563c 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -31,6 +31,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/i2c-tegra.h>
+#include <linux/spinlock.h>
 
 #include <asm/unaligned.h>
 
@@ -125,10 +126,12 @@ struct tegra_i2c_dev {
 	struct clk *clk;
 	struct resource *iomem;
 	struct rt_mutex dev_lock;
+	spinlock_t clk_lock;
 	void __iomem *base;
 	int cont_id;
 	int irq;
 	bool irq_disabled;
+	bool controller_enabled;
 	int is_dvc;
 	bool is_slave;
 	struct completion msg_complete;
@@ -385,6 +388,14 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 	u32 status;
 	const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | I2C_INT_TX_FIFO_OVERFLOW;
 	struct tegra_i2c_dev *i2c_dev = dev_id;
+	unsigned long flags;
+
+	spin_lock_irqsave(&i2c_dev->clk_lock, flags);
+	if (!i2c_dev->controller_enabled) {
+		dev_warn(i2c_dev->dev, "Controller not enabled\n");
+		spin_unlock_irqrestore(&i2c_dev->clk_lock, flags);
+		return IRQ_NONE;
+	}
 
 	status = i2c_readl(i2c_dev, I2C_INT_STATUS);
 
@@ -398,7 +409,6 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 			i2c_dev->irq_disabled = 1;
 		}
 
-		complete(&i2c_dev->msg_complete);
 		goto err;
 	}
 
@@ -427,8 +437,6 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 			dev_warn(i2c_dev->dev, "Packet status 0x%08x\n",
 				i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS));
 		}
-		complete(&i2c_dev->msg_complete);
-
 		goto err;
 	}
 
@@ -444,7 +452,6 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 			i2c_dev->irq_disabled = 1;
 		}
 
-		complete(&i2c_dev->msg_complete);
 		goto err;
 	}
 
@@ -465,13 +472,15 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 	if (status & I2C_INT_PACKET_XFER_COMPLETE)
 		i2c_dev->msg_transfer_complete = 1;
 
-	if (i2c_dev->msg_transfer_complete && !i2c_dev->msg_buf_remaining)
-		complete(&i2c_dev->msg_complete);
 	i2c_writel(i2c_dev, status, I2C_INT_STATUS);
 
 	if (i2c_dev->is_dvc)
 		dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
 
+	if (i2c_dev->msg_transfer_complete && !i2c_dev->msg_buf_remaining)
+		complete(&i2c_dev->msg_complete);
+
+	spin_unlock_irqrestore(&i2c_dev->clk_lock, flags);
 	return IRQ_HANDLED;
 
 err:
@@ -505,6 +514,8 @@ err:
 	if (i2c_dev->is_dvc)
 		dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
 
+	complete(&i2c_dev->msg_complete);
+	spin_unlock_irqrestore(&i2c_dev->clk_lock, flags);
 	return IRQ_HANDLED;
 }
 
@@ -514,6 +525,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_bus *i2c_bus,
 	struct tegra_i2c_dev *i2c_dev = i2c_bus->dev;
 	u32 int_mask;
 	int ret;
+	unsigned long flags;
 
 	tegra_i2c_flush_fifos(i2c_dev);
 
@@ -570,7 +582,10 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_bus *i2c_bus,
 			"i2c transfer timed out, addr 0x%04x, data 0x%02x\n",
 			msg->addr, msg->buf[0]);
 
+		spin_lock_irqsave(&i2c_dev->clk_lock, flags);
+		i2c_dev->controller_enabled = false;
 		tegra_i2c_init(i2c_dev);
+		spin_unlock_irqrestore(&i2c_dev->clk_lock, flags);
 		return -ETIMEDOUT;
 	}
 
@@ -580,7 +595,11 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_bus *i2c_bus,
 	if (likely(i2c_dev->msg_err == I2C_ERR_NONE))
 		return 0;
 
+	spin_lock_irqsave(&i2c_dev->clk_lock, flags);
+	i2c_dev->controller_enabled = false;
 	tegra_i2c_init(i2c_dev);
+	spin_unlock_irqrestore(&i2c_dev->clk_lock, flags);
+
 	if (i2c_dev->msg_err == I2C_ERR_NO_ACK) {
 		if (msg->flags & I2C_M_IGNORE_NAK)
 			return 0;
@@ -600,6 +619,7 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 	struct tegra_i2c_dev *i2c_dev = i2c_bus->dev;
 	int i;
 	int ret = 0;
+	unsigned long flags;
 
 	if (i2c_dev->is_suspended)
 		return -EBUSY;
@@ -625,6 +645,11 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 
 	if (!i2c_dev->is_clkon_always)
 		clk_enable(i2c_dev->clk);
+
+	spin_lock_irqsave(&i2c_dev->clk_lock, flags);
+	i2c_dev->controller_enabled = true;
+	spin_unlock_irqrestore(&i2c_dev->clk_lock, flags);
+
 	for (i = 0; i < num; i++) {
 		int stop = (i == (num - 1)) ? 1  : 0;
 		ret = tegra_i2c_xfer_msg(i2c_bus, &msgs[i], stop);
@@ -634,6 +659,10 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 	ret = i;
 
 out:
+	spin_lock_irqsave(&i2c_dev->clk_lock, flags);
+	i2c_dev->controller_enabled = false;
+	spin_unlock_irqrestore(&i2c_dev->clk_lock, flags);
+
 	if (!i2c_dev->is_clkon_always)
 		clk_disable(i2c_dev->clk);
 
@@ -731,7 +760,9 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	i2c_dev->last_bus_clk = plat->bus_clk_rate[0] ?: 100000;
 	i2c_dev->msgs = NULL;
 	i2c_dev->msgs_num = 0;
+	i2c_dev->controller_enabled = false;
 	rt_mutex_init(&i2c_dev->dev_lock);
+	spin_lock_init(&i2c_dev->clk_lock);
 
 	i2c_dev->slave_addr = plat->slave_addr;
 	i2c_dev->is_dvc = plat->is_dvc;