ectool: Revert "ectool: Remove CROS_EC_DEV_IOCRDMEM"

CROS_EC_DEV_IOCRDMEM must be used on architecture where legacy IO mapped
registers are accessed inderectly via EMI. The kernel is taking care of
the translation.

TEST=Check on reks that we need to use the IOCTL.
BUG=chrome-os-partner:52550,chromium:602832
BRANCH=none

This reverts commit de45353bbdf0 ("ectool: Remove CROS_EC_DEV_IOCRDMEM").

Change-Id: I8efad56df90c58c25bdc9ccd70a508547e629a77
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/340348
Reviewed-by: Shawn N <shawnn@chromium.org>

4 files changed, 70 insertions, 39 deletions

diff --git a/util/comm-dev.c b/util/comm-dev.c
index 3b215d924d..94a5cdde52 100644
--- a/util/comm-dev.c
+++ b/util/comm-dev.c
@@ -91,6 +91,31 @@ static int ec_command_dev(int command, int version,
 	return r;
 }
 
+static int ec_readmem_dev(int offset, int bytes, void *dest)
+{
+	struct cros_ec_readmem s_mem;
+	struct ec_params_read_memmap r_mem;
+	int r;
+	static int fake_it;
+
+	if (!fake_it) {
+		s_mem.offset = offset;
+		s_mem.bytes = bytes;
+		s_mem.buffer = dest;
+		r = ioctl(fd, CROS_EC_DEV_IOCRDMEM, &s_mem);
+		if (r < 0 && errno == ENOTTY)
+			fake_it = 1;
+		else
+			return r;
+	}
+
+	r_mem.offset = offset;
+	r_mem.size = bytes;
+	return ec_command_dev(EC_CMD_READ_MEMMAP, 0,
+			      &r_mem, sizeof(r_mem),
+			      dest, bytes);
+}
+
 /* New ioctl format, used by Chrome OS 4.4 and later as well as upstream 4.0+ */
 
 static int ec_command_dev_v2(int command, int version,
@@ -131,6 +156,8 @@ static int ec_command_dev_v2(int command, int version,
 	} else {
 		memcpy(indata, s_cmd->data, MIN(r, insize));
 		if (s_cmd->result != EC_RES_SUCCESS) {
+			fprintf(stderr, "EC result %d (%s)\n", s_cmd->result,
+				strresult(s_cmd->result));
 			r =  -EECRESULT - s_cmd->result;
 		}
 	}
@@ -139,6 +166,31 @@ static int ec_command_dev_v2(int command, int version,
 	return r;
 }
 
+static int ec_readmem_dev_v2(int offset, int bytes, void *dest)
+{
+	struct cros_ec_readmem_v2 s_mem;
+	struct ec_params_read_memmap r_mem;
+	int r;
+	static int fake_it;
+
+	if (!fake_it) {
+		s_mem.offset = offset;
+		s_mem.bytes = bytes;
+		r = ioctl(fd, CROS_EC_DEV_IOCRDMEM_V2, &s_mem);
+		if (r < 0 && errno == ENOTTY) {
+			fake_it = 1;
+		} else {
+			memcpy(dest, s_mem.buffer, bytes);
+			return r;
+		}
+	}
+
+	r_mem.offset = offset;
+	r_mem.size = bytes;
+	return ec_command_dev(EC_CMD_READ_MEMMAP, 0,
+			      &r_mem, sizeof(r_mem),
+			      dest, bytes);
+}
 
 /*
  * Attempt to communicate with kernel using old ioctl format.
@@ -169,6 +221,7 @@ static int ec_dev_is_v2(void)
 
 int comm_init_dev(const char *device_name)
 {
+	int (*ec_cmd_readmem)(int offset, int bytes, void *dest);
 	char version[80];
 	char device[80] = "/dev/";
 	int r;
@@ -195,20 +248,15 @@ int comm_init_dev(const char *device_name)
 
 	if (ec_dev_is_v2()) {
 		ec_command_proto = ec_command_dev_v2;
+		ec_cmd_readmem = ec_readmem_dev_v2;
 	} else {
 		ec_command_proto = ec_command_dev;
+		ec_cmd_readmem = ec_readmem_dev;
 	}
 
-	if (ec_readmem(EC_MEMMAP_ID, 2, version) < 0) {
-		/*
-		 * Unable to read memory map through command protocol,
-		 * assume LPC transport underneath.
-		 */
-		comm_init_lpc(1);
-		if (ec_readmem(EC_MEMMAP_ID, 2, version) < 0)
-			fprintf(stderr,
-				"Unable to read memory mapped registers.\n");
-	}
+	if (ec_cmd_readmem(EC_MEMMAP_ID, 2, version) == 2 &&
+	    version[0] == 'E' && version[1] == 'C')
+		ec_readmem = ec_cmd_readmem;
 
 	/*
 	 * Set temporary size, will be updated later.
diff --git a/util/comm-host.c b/util/comm-host.c
index f7514904cd..31ad56343e 100644
--- a/util/comm-host.c
+++ b/util/comm-host.c
@@ -25,6 +25,10 @@ void *ec_outbuf;
 void *ec_inbuf;
 static int command_offset;
 
+int comm_init_dev(const char *device_name) __attribute__((weak));
+int comm_init_lpc(void) __attribute__((weak));
+int comm_init_i2c(void) __attribute__((weak));
+
 static int fake_readmem(int offset, int bytes, void *dest)
 {
 	struct ec_params_read_memmap p;
@@ -88,15 +92,16 @@ int comm_init(int interfaces, const char *device_name)
 	}
 
 	/* Prefer new /dev method */
-	if ((interfaces & COMM_DEV) && !comm_init_dev(device_name))
+	if ((interfaces & COMM_DEV) && comm_init_dev &&
+	    !comm_init_dev(device_name))
 		goto init_ok;
 
 	/* Fallback to direct LPC on x86 */
-	if ((interfaces & COMM_LPC) && !comm_init_lpc(0))
+	if ((interfaces & COMM_LPC) && comm_init_lpc && !comm_init_lpc())
 		goto init_ok;
 
 	/* Fallback to direct i2c on ARM */
-	if ((interfaces & COMM_I2C) && !comm_init_i2c())
+	if ((interfaces & COMM_I2C) && comm_init_i2c && !comm_init_i2c())
 		goto init_ok;
 
 	/* Give up */
diff --git a/util/comm-host.h b/util/comm-host.h
index bfe99b2179..1d3cb9e36d 100644
--- a/util/comm-host.h
+++ b/util/comm-host.h
@@ -74,15 +74,4 @@ extern int (*ec_command_proto)(int command, int version,
  */
 extern int (*ec_readmem)(int offset, int bytes, void *dest);
 
-/*
- * Functions for initializing communication protocols.
- * @param device_name: device name to open to access the ec.
- * @param init_readmem_only:
- *  1: init only ec_readmem
- *  0: set ec_command_proto as well.
- */
-int comm_init_dev(const char *device_name);
-int comm_init_lpc(int init_readmem_only);
-int comm_init_i2c(void);
-
 #endif /* __UTIL_COMM_HOST_H */
diff --git a/util/comm-lpc.c b/util/comm-lpc.c
index 27a32f3b69..54f16b3ffc 100644
--- a/util/comm-lpc.c
+++ b/util/comm-lpc.c
@@ -246,7 +246,7 @@ static int ec_readmem_lpc(int offset, int bytes, void *dest)
 	return cnt;
 }
 
-int comm_init_lpc(int init_readmem_only)
+int comm_init_lpc(void)
 {
 	int i;
 	int byte = 0xff;
@@ -257,13 +257,6 @@ int comm_init_lpc(int init_readmem_only)
 		return -3;
 	}
 
-	ec_readmem = ec_readmem_lpc;
-
-	if (init_readmem_only) {
-		/* Function to send commands already defined. */
-		return 0;
-	}
-
 	/*
 	 * Test if the I/O port has been configured for Chromium EC LPC
 	 * interface.  Chromium EC guarantees that at least one status bit will
@@ -315,13 +308,9 @@ int comm_init_lpc(int init_readmem_only)
 		return -5;
 	}
 
+	/* Either one supports reading mapped memory directly. */
+	ec_readmem = ec_readmem_lpc;
 	return 0;
 }
 
-#else  /* defined(__i386__) || defined(__x86_64__) */
-#include <errno.h>
-int comm_init_lpc(int unused)
-{
-	return -EOPNOTSUPP;
-}
-#endif  /* defined(__i386__) || defined(__x86_64__) */
+#endif