@@ -98,7 +98,6 @@
#define RCAR_IRQ_STOP (MST)
#define ID_LAST_MSG (1 << 0)
-#define ID_FIRST_MSG (1 << 1)
#define ID_DONE (1 << 2)
#define ID_ARBLOST (1 << 3)
#define ID_NACK (1 << 4)
@@ -333,11 +332,19 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv)
return 0;
}
+/*
+ * We don't have a test case but the HW engineers say that the write order of
+ * ICMSR and ICMCR depends on whether we issue START or REP_START. So, ICMSR
+ * handling is outside of this function. First messages clear ICMSR before this
+ * function, interrupt handlers clear the relevant bits after this function.
+ */
static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv)
{
int read = !!rcar_i2c_is_recv(priv);
priv->pos = 0;
+ priv->flags &= ID_P_MASK;
+
if (priv->msgs_left == 1)
priv->flags |= ID_LAST_MSG;
@@ -345,29 +352,27 @@ static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv)
if (!priv->atomic_xfer)
rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND);
- /*
- * We don't have a test case but the HW engineers say that the write order
- * of ICMSR and ICMCR depends on whether we issue START or REP_START. Since
- * it didn't cause a drawback for me, let's rather be safe than sorry.
- */
- if (priv->flags & ID_FIRST_MSG) {
- rcar_i2c_write(priv, ICMSR, 0);
+ if (priv->flags & ID_P_REP_AFTER_RD)
+ priv->flags &= ~ID_P_REP_AFTER_RD;
+ else
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
- } else {
- if (priv->flags & ID_P_REP_AFTER_RD)
- priv->flags &= ~ID_P_REP_AFTER_RD;
- else
- rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
- /* ICMSR is cleared in interrupt handlers */
- }
+}
+
+static void rcar_i2c_first_msg(struct rcar_i2c_priv *priv,
+ struct i2c_msg *msgs, int num)
+{
+ priv->msg = msgs;
+ priv->msgs_left = num;
+ rcar_i2c_write(priv, ICMSR, 0); /* must be before preparing msg */
+ rcar_i2c_prepare_msg(priv);
}
static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv)
{
priv->msg++;
priv->msgs_left--;
- priv->flags &= ID_P_MASK;
rcar_i2c_prepare_msg(priv);
+ /* ICMSR handling must come afterwards in the irq handler */
}
static void rcar_i2c_cleanup_dma(struct rcar_i2c_priv *priv, bool terminate)
@@ -852,11 +857,7 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
for (i = 0; i < num; i++)
rcar_i2c_request_dma(priv, msgs + i);
- /* init first message */
- priv->msg = msgs;
- priv->msgs_left = num;
- priv->flags = (priv->flags & ID_P_MASK) | ID_FIRST_MSG;
- rcar_i2c_prepare_msg(priv);
+ rcar_i2c_first_msg(priv, msgs, num);
time_left = wait_event_timeout(priv->wait, priv->flags & ID_DONE,
num * adap->timeout);
@@ -906,12 +907,7 @@ static int rcar_i2c_master_xfer_atomic(struct i2c_adapter *adap,
goto out;
rcar_i2c_init(priv);
-
- /* init first message */
- priv->msg = msgs;
- priv->msgs_left = num;
- priv->flags = (priv->flags & ID_P_MASK) | ID_FIRST_MSG;
- rcar_i2c_prepare_msg(priv);
+ rcar_i2c_first_msg(priv, msgs, num);
j = jiffies + num * adap->timeout;
do {
After moving ICMSR handling to interrupt handlers previously to fix a race condition, we can now also move ICMSR handling for the first message out of the function to prepare a message. By introducing a seperate function to initialize the first message, we can not only remove some code duplication but the remaining code is also easier to follow. The function to prepare a message is much simpler without ICMSR handling. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> --- drivers/i2c/busses/i2c-rcar.c | 50 ++++++++++++++++------------------- 1 file changed, 23 insertions(+), 27 deletions(-)