1 files changed, 48 insertions, 18 deletions

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 217def2d7cb4..12f6d452c0f7 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -91,7 +91,6 @@
 
 #define RCAR_BUS_PHASE_START	(MDBS | MIE | ESG)
 #define RCAR_BUS_PHASE_DATA	(MDBS | MIE)
-#define RCAR_BUS_MASK_DATA	(~(ESG | FSB) & 0xFF)
 #define RCAR_BUS_PHASE_STOP	(MDBS | MIE | FSB)
 
 #define RCAR_IRQ_SEND	(MNR | MAL | MST | MAT | MDE)
@@ -120,6 +119,7 @@ enum rcar_i2c_type {
 };
 
 struct rcar_i2c_priv {
+	u32 flags;
 	void __iomem *io;
 	struct i2c_adapter adap;
 	struct i2c_msg *msg;
@@ -130,7 +130,6 @@ struct rcar_i2c_priv {
 
 	int pos;
 	u32 icccr;
-	u32 flags;
 	u8 recovery_icmcr;	/* protected by adapter lock */
 	enum rcar_i2c_type devtype;
 	struct i2c_client *slave;
@@ -621,27 +620,16 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
 /*
  * This driver has a lock-free design because there are IP cores (at least
  * R-Car Gen2) which have an inherent race condition in their hardware design.
- * There, we need to clear RCAR_BUS_MASK_DATA bits as soon as possible after
+ * There, we need to switch to RCAR_BUS_PHASE_DATA as soon as possible after
  * the interrupt was generated, otherwise an unwanted repeated message gets
  * generated. It turned out that taking a spinlock at the beginning of the ISR
  * was already causing repeated messages. Thus, this driver was converted to
  * the now lockless behaviour. Please keep this in mind when hacking the driver.
+ * R-Car Gen3 seems to have this fixed but earlier versions than R-Car Gen2 are
+ * likely affected. Therefore, we have different interrupt handler entries.
  */
-static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
+static irqreturn_t rcar_i2c_irq(int irq, struct rcar_i2c_priv *priv, u32 msr)
 {
-	struct rcar_i2c_priv *priv = ptr;
-	u32 msr, val;
-
-	/* Clear START or STOP immediately, except for REPSTART after read */
-	if (likely(!(priv->flags & ID_P_REP_AFTER_RD))) {
-		val = rcar_i2c_read(priv, ICMCR);
-		rcar_i2c_write(priv, ICMCR, val & RCAR_BUS_MASK_DATA);
-	}
-
-	msr = rcar_i2c_read(priv, ICMSR);
-
-	/* Only handle interrupts that are currently enabled */
-	msr &= rcar_i2c_read(priv, ICMIER);
 	if (!msr) {
 		if (rcar_i2c_slave_irq(priv))
 			return IRQ_HANDLED;
@@ -685,6 +673,41 @@ out:
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t rcar_i2c_gen2_irq(int irq, void *ptr)
+{
+	struct rcar_i2c_priv *priv = ptr;
+	u32 msr;
+
+	/* Clear START or STOP immediately, except for REPSTART after read */
+	if (likely(!(priv->flags & ID_P_REP_AFTER_RD)))
+		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
+
+	/* Only handle interrupts that are currently enabled */
+	msr = rcar_i2c_read(priv, ICMSR);
+	msr &= rcar_i2c_read(priv, ICMIER);
+
+	return rcar_i2c_irq(irq, priv, msr);
+}
+
+static irqreturn_t rcar_i2c_gen3_irq(int irq, void *ptr)
+{
+	struct rcar_i2c_priv *priv = ptr;
+	u32 msr;
+
+	/* Only handle interrupts that are currently enabled */
+	msr = rcar_i2c_read(priv, ICMSR);
+	msr &= rcar_i2c_read(priv, ICMIER);
+
+	/*
+	 * Clear START or STOP immediately, except for REPSTART after read or
+	 * if a spurious interrupt was detected.
+	 */
+	if (likely(!(priv->flags & ID_P_REP_AFTER_RD) && msr))
+		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
+
+	return rcar_i2c_irq(irq, priv, msr);
+}
+
 static struct dma_chan *rcar_i2c_request_dma_chan(struct device *dev,
 					enum dma_transfer_direction dir,
 					dma_addr_t port_addr)
@@ -931,6 +954,8 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 	struct rcar_i2c_priv *priv;
 	struct i2c_adapter *adap;
 	struct device *dev = &pdev->dev;
+	unsigned long irqflags = 0;
+	irqreturn_t (*irqhandler)(int irq, void *ptr) = rcar_i2c_gen3_irq;
 	int ret;
 
 	/* Otherwise logic will break because some bytes must always use PIO */
@@ -979,6 +1004,11 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 
 	rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */
 
+	if (priv->devtype < I2C_RCAR_GEN3) {
+		irqflags |= IRQF_NO_THREAD;
+		irqhandler = rcar_i2c_gen2_irq;
+	}
+
 	if (priv->devtype == I2C_RCAR_GEN3) {
 		priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
 		if (!IS_ERR(priv->rstc)) {
@@ -998,7 +1028,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 		priv->flags |= ID_P_HOST_NOTIFY;
 
 	priv->irq = platform_get_irq(pdev, 0);
-	ret = devm_request_irq(dev, priv->irq, rcar_i2c_irq, 0, dev_name(dev), priv);
+	ret = devm_request_irq(dev, priv->irq, irqhandler, irqflags, dev_name(dev), priv);
 	if (ret < 0) {
 		dev_err(dev, "cannot get irq %d\n", priv->irq);
 		goto out_pm_disable;