Subject: [PATCH V7 1/6] i2c: qup: Change qup_wait_writeready function to use for all timeouts

From: [email-masked] (Sricharan R)
Date: Tue, 19 Jan 2016 15:32:41 +0530

qup_wait_writeready waits only on a output fifo empty event.
Change the same function to accept the event and data length
to wait as parameters. This way the same function can be used for
timeouts in other places as well.

Signed-off-by: Sricharan R <[email-masked]>
Reviewed-by: Andy Gross <[email-masked]>
Tested-by: Archit Taneja <[email-masked]>
Tested-by: Telkar Nagender <[email-masked]>
---
 drivers/i2c/busses/i2c-qup.c | 67 +++++++++++++++++++++++++++++++-------------
 1 file changed, 48 insertions(+), 19 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index fdcbdab..81ed120 100644
--- a/drivers/i2c/busses/i2c-qup.c
+++ b/drivers/i2c/busses/i2c-qup.c
@@ -98,6 +98,9 @@
 #define QUP_STATUS_ERROR_FLAGS		0x7c
 
 #define QUP_READ_LIMIT			256
+#define SET_BIT				0x1
+#define RESET_BIT			0x0
+#define ONE_BYTE			0x1
 
 struct qup_i2c_dev {
 	struct device		*dev;
@@ -221,26 +224,42 @@ static int qup_i2c_change_state(struct qup_i2c_dev *qup, u32 state)
 	return 0;
 }
 
-static int qup_i2c_wait_writeready(struct qup_i2c_dev *qup)
+/**
+ * qup_i2c_wait_ready - wait for a give number of bytes in tx/rx path
+ * @qup: The qup_i2c_dev device
+ * @op: The bit/event to wait on
+ * @val: value of the bit to wait on, 0 or 1
+ * @len: The length the bytes to be transferred
+ */
+static int qup_i2c_wait_ready(struct qup_i2c_dev *qup, int op, bool val,
+			      int len)
 {
 	unsigned long timeout;
 	u32 opflags;
 	u32 status;
+	u32 shift = __ffs(op);
 
-	timeout = jiffies + HZ;
+	len *= qup->one_byte_t;
+	/* timeout after a wait of twice the max time */
+	timeout = jiffies + len * 4;
 
 	for (;;) {
 		opflags = readl(qup->base + QUP_OPERATIONAL);
 		status = readl(qup->base + QUP_I2C_STATUS);
 
-		if (!(opflags & QUP_OUT_NOT_EMPTY) &&
-		    !(status & I2C_STATUS_BUS_ACTIVE))
-			return 0;
+		if (((opflags & op) >> shift) == val) {
+			if (op == QUP_OUT_NOT_EMPTY) {
+				if (!(status & I2C_STATUS_BUS_ACTIVE))
+					return 0;
+			} else {
+				return 0;
+			}
+		}
 
 		if (time_after(jiffies, timeout))
 			return -ETIMEDOUT;
 
-		usleep_range(qup->one_byte_t, qup->one_byte_t * 2);
+		usleep_range(len, len * 2);
 	}
 }
 
@@ -261,13 +280,13 @@ static void qup_i2c_set_write_mode(struct qup_i2c_dev *qup, struct i2c_msg *msg)
 	}
 }
 
-static void qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg *msg)
+static int qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg *msg)
 {
 	u32 addr = msg->addr << 1;
 	u32 qup_tag;
-	u32 opflags;
 	int idx;
 	u32 val;
+	int ret = 0;
 
 	if (qup->pos == 0) {
 		val = QUP_TAG_START | addr;
@@ -279,9 +298,10 @@ static void qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg *msg)
 
 	while (qup->pos < msg->len) {
 		/* Check that there's space in the FIFO for our pair */
-		opflags = readl(qup->base + QUP_OPERATIONAL);
-		if (opflags & QUP_OUT_FULL)
-			break;
+		ret = qup_i2c_wait_ready(qup, QUP_OUT_FULL, RESET_BIT,
+					 4 * ONE_BYTE);
+		if (ret)
+			return ret;
 
 		if (qup->pos == msg->len - 1)
 			qup_tag = QUP_TAG_STOP;
@@ -300,6 +320,8 @@ static void qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg *msg)
 		qup->pos++;
 		idx++;
 	}
+
+	return ret;
 }
 
 static int qup_i2c_write_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
@@ -325,7 +347,9 @@ static int qup_i2c_write_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
 		if (ret)
 			goto err;
 
-		qup_i2c_issue_write(qup, msg);
+		ret = qup_i2c_issue_write(qup, msg);
+		if (ret)
+			goto err;
 
 		ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
 		if (ret)
@@ -347,7 +371,7 @@ static int qup_i2c_write_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
 	} while (qup->pos < msg->len);
 
 	/* Wait for the outstanding data in the fifo to drain */
-	ret = qup_i2c_wait_writeready(qup);
+	ret = qup_i2c_wait_ready(qup, QUP_OUT_NOT_EMPTY, RESET_BIT, ONE_BYTE);
 
 err:
 	disable_irq(qup->irq);
@@ -384,18 +408,19 @@ static void qup_i2c_issue_read(struct qup_i2c_dev *qup, struct i2c_msg *msg)
 }

-static void qup_i2c_read_fifo(struct qup_i2c_dev *qup, struct i2c_msg *msg)
+static int qup_i2c_read_fifo(struct qup_i2c_dev *qup, struct i2c_msg *msg)
 {
-	u32 opflags;
 	u32 val = 0;
 	int idx;
+	int ret = 0;
 
 	for (idx = 0; qup->pos < msg->len; idx++) {
 		if ((idx & 1) == 0) {
 			/* Check that FIFO have data */
-			opflags = readl(qup->base + QUP_OPERATIONAL);
-			if (!(opflags & QUP_IN_NOT_EMPTY))
-				break;
+			ret = qup_i2c_wait_ready(qup, QUP_IN_NOT_EMPTY,
+						 SET_BIT, 4 * ONE_BYTE);
+			if (ret)
+				return ret;
 
 			/* Reading 2 words at time */
 			val = readl(qup->base + QUP_IN_FIFO_BASE);
@@ -405,6 +430,8 @@ static void qup_i2c_read_fifo(struct qup_i2c_dev *qup, struct i2c_msg *msg)
 			msg->buf[qup->pos++] = val >> QUP_MSW_SHIFT;
 		}
 	}
+
+	return ret;
 }
 
 static int qup_i2c_read_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
@@ -450,7 +477,9 @@ static int qup_i2c_read_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
 			goto err;
 		}
 
-		qup_i2c_read_fifo(qup, msg);
+		ret = qup_i2c_read_fifo(qup, msg);
+		if (ret)
+			goto err;
 	} while (qup->pos < msg->len);
 
 err:
-- 
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