i2c: omap: resize fifos before each message
This patch will try to avoid the usage of
draining feature by reconfiguring the FIFO
the start condition of each message based
on the message's size.
By doing that, we will be better utilizing
the FIFO when doing big transfers.
While at that also drop the now unneeded
check for dev->buf_len as we always know
the amount of data to be transmitted.
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 4af123f..f33bc5a 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -193,6 +193,7 @@
u8 *regs;
size_t buf_len;
struct i2c_adapter adapter;
+ u8 threshold;
u8 fifo_size; /* use as flag and value
* fifo_size==0 implies no fifo
* if set, should be trsh+1
@@ -418,13 +419,6 @@
omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);
omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);
- if (dev->fifo_size) {
- /* Note: setup required fifo size - 1. RTRSH and XTRSH */
- buf = (dev->fifo_size - 1) << 8 | OMAP_I2C_BUF_RXFIF_CLR |
- (dev->fifo_size - 1) | OMAP_I2C_BUF_TXFIF_CLR;
- omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf);
- }
-
/* Take the I2C module out of reset: */
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
@@ -462,6 +456,45 @@
return 0;
}
+static void omap_i2c_resize_fifo(struct omap_i2c_dev *dev, u8 size, bool is_rx)
+{
+ u16 buf;
+
+ if (dev->flags & OMAP_I2C_FLAG_NO_FIFO)
+ return;
+
+ /*
+ * Set up notification threshold based on message size. We're doing
+ * this to try and avoid draining feature as much as possible. Whenever
+ * we have big messages to transfer (bigger than our total fifo size)
+ * then we might use draining feature to transfer the remaining bytes.
+ */
+
+ dev->threshold = clamp(size, (u8) 1, dev->fifo_size);
+
+ buf = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG);
+
+ if (is_rx) {
+ /* Clear RX Threshold */
+ buf &= ~(0x3f << 8);
+ buf |= ((dev->threshold - 1) << 8) | OMAP_I2C_BUF_RXFIF_CLR;
+ } else {
+ /* Clear TX Threshold */
+ buf &= ~0x3f;
+ buf |= (dev->threshold - 1) | OMAP_I2C_BUF_TXFIF_CLR;
+ }
+
+ omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf);
+
+ if (dev->rev < OMAP_I2C_REV_ON_3630_4430)
+ dev->b_hw = 1; /* Enable hardware fixes */
+
+ /* calculate wakeup latency constraint for MPU */
+ if (dev->set_mpu_wkup_lat != NULL)
+ dev->latency = (1000000 * dev->threshold) /
+ (1000 * dev->speed / 8);
+}
+
/*
* Low level master read/write transaction.
*/
@@ -478,6 +511,9 @@
if (msg->len == 0)
return -EINVAL;
+ dev->receiver = !!(msg->flags & I2C_M_RD);
+ omap_i2c_resize_fifo(dev, msg->len, dev->receiver);
+
omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr);
/* REVISIT: Could the STB bit of I2C_CON be used with probing? */
@@ -493,7 +529,6 @@
INIT_COMPLETION(dev->cmd_complete);
dev->cmd_err = 0;
- dev->receiver = !!(msg->flags & I2C_M_RD);
w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
@@ -760,12 +795,6 @@
u16 w;
while (num_bytes--) {
- if (!dev->buf_len) {
- dev_err(dev->dev, "%s without data",
- is_rdr ? "RDR" : "RRDY");
- break;
- }
-
w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
*dev->buf++ = w;
dev->buf_len--;
@@ -775,10 +804,8 @@
* omap4 is 8 bit wide
*/
if (dev->flags & OMAP_I2C_FLAG_16BIT_DATA_REG) {
- if (dev->buf_len) {
- *dev->buf++ = w >> 8;
- dev->buf_len--;
- }
+ *dev->buf++ = w >> 8;
+ dev->buf_len--;
}
}
}
@@ -789,12 +816,6 @@
u16 w;
while (num_bytes--) {
- if (!dev->buf_len) {
- dev_err(dev->dev, "%s without data",
- is_xdr ? "XDR" : "XRDY");
- break;
- }
-
w = *dev->buf++;
dev->buf_len--;
@@ -803,10 +824,8 @@
* omap4 is 8 bit wide
*/
if (dev->flags & OMAP_I2C_FLAG_16BIT_DATA_REG) {
- if (dev->buf_len) {
- w |= *dev->buf++ << 8;
- dev->buf_len--;
- }
+ w |= *dev->buf++ << 8;
+ dev->buf_len--;
}
if (dev->errata & I2C_OMAP_ERRATA_I462) {
@@ -901,8 +920,8 @@
if (stat & OMAP_I2C_STAT_RRDY) {
u8 num_bytes = 1;
- if (dev->fifo_size)
- num_bytes = dev->fifo_size;
+ if (dev->threshold)
+ num_bytes = dev->threshold;
omap_i2c_receive_data(dev, num_bytes, false);
omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RRDY);
@@ -929,8 +948,8 @@
u8 num_bytes = 1;
int ret;
- if (dev->fifo_size)
- num_bytes = dev->fifo_size;
+ if (dev->threshold)
+ num_bytes = dev->threshold;
ret = omap_i2c_transmit_data(dev, num_bytes, false);
stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);