i2c: Move to Linux like `struct i2c_msg`

Our current struct for I2C segments `i2c_seg` was close to being compa-
tible to the Linux version `i2c_msg`, close to being compatible to SMBus
and close to being readable (e.g. what was `chip` supposed to mean?) but
turned out to be hard to fix.

Instead of extending it in a backwards compatible way (and not touching
current controller drivers), replace it with a Linux source compatible
`struct i2c_msg` and patch all the drivers and users with Coccinelle.

The new `struct i2c_msg` should ease porting drivers from Linux and help
to write SMBus compatible controller drivers.

Beside integer type changes, the field `read` is replaced with a generic
field `flags` and `chip` is renamed to `slave`.

Patched with Coccinelle using the clumsy spatch below and some manual
changes:

* Nested struct initializers and one field access skipped by Coccinelle.
* Removed assumption in the code that I2C_M_RD is 1.
* In `i2c.h`, changed all occurences of `chip` to `slave`.

    @@ @@
    -struct i2c_seg
    +struct i2c_msg

    @@ identifier msg; expression e; @@
    (
     struct i2c_msg msg = {
    -    .read = 0,
    +    .flags = 0,
     };
    |
     struct i2c_msg msg = {
    -    .read = 1,
    +    .flags = I2C_M_RD,
     };
    |
     struct i2c_msg msg = {
    -    .chip = e,
    +    .slave = e,
     };
    )

    @@ struct i2c_msg msg; statement S1, S2; @@
    (
    -if (msg.read)
    +if (msg.flags & I2C_M_RD)
     S1 else S2
    |
    -if (msg.read)
    +if (msg.flags & I2C_M_RD)
     S1
    )

    @@ struct i2c_msg *msg; statement S1, S2; @@
    (
    -if (msg->read)
    +if (msg->flags & I2C_M_RD)
     S1 else S2
    |
    -if (msg->read)
    +if (msg->flags & I2C_M_RD)
     S1
    )

    @@ struct i2c_msg msg; expression e; @@
    (
    -msg.read = 0;
    +msg.flags = 0;
    |
    -msg.read = 1;
    +msg.flags = I2C_M_RD;
    |
    -msg.read = e;
    +msg.flags = e ? I2C_M_RD : 0;
    |
    -!!(msg.read)
    +(msg.flags & I2C_M_RD)
    |
    -(msg.read)
    +(msg.flags & I2C_M_RD)
    )

    @@ struct i2c_msg *msg; expression e; @@
    (
    -msg->read = 0;
    +msg->flags = 0;
    |
    -msg->read = 1;
    +msg->flags = I2C_M_RD;
    |
    -msg->read = e;
    +msg->flags = e ? I2C_M_RD : 0;
    |
    -!!(msg->read)
    +(msg->flags & I2C_M_RD)
    |
    -(msg->read)
    +(msg->flags & I2C_M_RD)
    )

    @@ struct i2c_msg msg; @@
    -msg.chip
    +msg.slave

    @@ struct i2c_msg *msg; expression e; @@
    -msg[e].chip
    +msg[e].slave

    @ slave disable ptr_to_array @ struct i2c_msg *msg; @@
    -msg->chip
    +msg->slave

Change-Id: Ifd7cabf0a18ffd7a1def25d1d7059b713d0b7ea9
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/20542
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

2 files changed, 19 insertions, 16 deletions

diff --git a/src/soc/intel/common/block/i2c/lpss_i2c.c b/src/soc/intel/common/block/i2c/lpss_i2c.c
index 5b188f8c22..711517f6d3 100644
--- a/src/soc/intel/common/block/i2c/lpss_i2c.c
+++ b/src/soc/intel/common/block/i2c/lpss_i2c.c
@@ -258,7 +258,7 @@ static int lpss_i2c_wait_for_bus_idle(struct lpss_i2c_regs *regs)
 
 /* Transfer one byte of one segment, sending stop bit if requested */
 static int lpss_i2c_transfer_byte(struct lpss_i2c_regs *regs,
-				  struct i2c_seg *segment,
+				  struct i2c_msg *segment,
 				  size_t byte, int send_stop)
 {
 	struct stopwatch sw;
@@ -266,7 +266,7 @@ static int lpss_i2c_transfer_byte(struct lpss_i2c_regs *regs,
 
 	stopwatch_init_usecs_expire(&sw, LPSS_I2C_TIMEOUT_US);
 
-	if (!segment->read) {
+	if (!(segment->flags & I2C_M_RD)) {
 		/* Write op only: Wait for FIFO not full */
 		while (!(read32(&regs->status) & STATUS_TX_FIFO_NOT_FULL)) {
 			if (stopwatch_expired(&sw)) {
@@ -283,7 +283,7 @@ static int lpss_i2c_transfer_byte(struct lpss_i2c_regs *regs,
 
 	write32(&regs->cmd_data, cmd);
 
-	if (segment->read) {
+	if (segment->flags & I2C_M_RD) {
 		/* Read op only: Wait for FIFO data and store it */
 		while (!(read32(&regs->status) & STATUS_RX_FIFO_NOT_EMPTY)) {
 			if (stopwatch_expired(&sw)) {
@@ -298,7 +298,8 @@ static int lpss_i2c_transfer_byte(struct lpss_i2c_regs *regs,
 }
 
 /* Global I2C bus handler, defined in include/i2c.h */
-int platform_i2c_transfer(unsigned int bus, struct i2c_seg *segments, int count)
+int platform_i2c_transfer(unsigned int bus, struct i2c_msg *segments,
+			  int count)
 {
 	struct stopwatch sw;
 	struct lpss_i2c_regs *regs;
@@ -325,11 +326,12 @@ int platform_i2c_transfer(unsigned int bus, struct i2c_seg *segments, int count)
 	while (count--) {
 		if (CONFIG_SOC_INTEL_COMMON_LPSS_I2C_DEBUG)
 			printk(BIOS_DEBUG, "i2c %u:%02x %s %d bytes : ",
-			       bus, segments->chip, segments->read ? "R" : "W",
+			       bus, segments->slave,
+			       (segments->flags & I2C_M_RD) ? "R" : "W",
 			       segments->len);
 
 		/* Set target slave address */
-		write32(&regs->target_addr, segments->chip);
+		write32(&regs->target_addr, segments->slave);
 
 		/* Read or write each byte in segment */
 		for (byte = 0; byte < segments->len; byte++) {
@@ -341,8 +343,9 @@ int platform_i2c_transfer(unsigned int bus, struct i2c_seg *segments, int count)
 			if (lpss_i2c_transfer_byte(regs, segments, byte,
 						   count == 0) < 0) {
 				printk(BIOS_ERR, "I2C %s failed: bus %u "
-				       "addr 0x%02x\n", segments->read ?
-				       "read" : "write", bus, segments->chip);
+				       "addr 0x%02x\n",
+				       (segments->flags & I2C_M_RD) ?
+				       "read" : "write", bus, segments->slave);
 				goto out;
 			}
 		}
diff --git a/src/soc/intel/quark/i2c.c b/src/soc/intel/quark/i2c.c
index 26017389b8..e8dba5376f 100644
--- a/src/soc/intel/quark/i2c.c
+++ b/src/soc/intel/quark/i2c.c
@@ -186,8 +186,8 @@ static int platform_i2c_read(uint32_t restart, uint8_t *rx_buffer, int length,
 	return bytes_transferred;
 }
 
-int platform_i2c_transfer(unsigned int bus, struct i2c_seg *segment,
-	int seg_count)
+int platform_i2c_transfer(unsigned int bus, struct i2c_msg *segment,
+			  int seg_count)
 {
 	int bytes_transferred;
 	uint8_t chip;
@@ -212,9 +212,9 @@ int platform_i2c_transfer(unsigned int bus, struct i2c_seg *segment,
 			printk(BIOS_ERR,
 				"I2C segment[%d]: %s 0x%02x %s 0x%p, 0x%08x bytes\n",
 				index,
-				segment[index].read ? "Read from" : "Write to",
-				segment[index].chip,
-				segment[index].read ? "to " : "from",
+				(segment[index].flags & I2C_M_RD) ? "Read from" : "Write to",
+				segment[index].slave,
+				(segment[index].flags & I2C_M_RD) ? "to " : "from",
 				segment[index].buf,
 				segment[index].len);
 			printk(BIOS_ERR, "I2C %s\n",
@@ -243,7 +243,7 @@ int platform_i2c_transfer(unsigned int bus, struct i2c_seg *segment,
 	regs->ic_con = cmd;
 
 	/* Set the target chip address */
-	chip = segment->chip;
+	chip = segment->slave;
 	regs->ic_tar = chip;
 
 	/* Enable the I2C controller */
@@ -270,13 +270,13 @@ int platform_i2c_transfer(unsigned int bus, struct i2c_seg *segment,
 		total_bytes += length;
 		ASSERT(segment->buf != NULL);
 		ASSERT(length >= 1);
-		ASSERT(segment->chip == chip);
+		ASSERT(segment->slave == chip);
 
 		/* Determine if this is the last segment of the transaction */
 		stop = (index == seg_count) ? IC_DATA_CMD_STOP : 0;
 
 		/* Fill the FIFO with the necessary command bytes */
-		if (segment->read) {
+		if (segment->flags & I2C_M_RD) {
 			/* Place read commands into the FIFO */
 			rx_buffer = segment->buf;
 			data_bytes = platform_i2c_read(restart, rx_buffer,