ectool prefers /dev/cros_ec, then falls back to i2c, lpc

This is preparation for the common userspace EC interface. If/when that
appears, this will be ready.

BUG=chromium:239197
BRANCH=all
TEST=manual

Build, install, run it. Shouldn't be any change.

Change-Id: I9fa78515ec5443ba659f10a66bbaadcb7f4802b0
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/56131

1 files changed, 77 insertions, 0 deletions

diff --git a/util/comm-host.c b/util/comm-host.c
new file mode 100644
index 0000000000..bf94927361
--- /dev/null
+++ b/util/comm-host.c
@@ -0,0 +1,77 @@
+/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "comm-host.h"
+#include "ec_commands.h"
+
+int (*ec_command)(int command, int version,
+		  const void *outdata, int outsize,
+		  void *indata, int insize);
+
+int (*ec_readmem)(int offset, int bytes, void *dest);
+
+int comm_init_dev(void) __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;
+	int c;
+	char *buf;
+
+	p.offset = offset;
+
+	if (bytes) {
+		p.size = bytes;
+		c = ec_command(EC_CMD_READ_MEMMAP, 0, &p, sizeof(p),
+			       dest, p.size);
+		if (c < 0)
+			return c;
+		return p.size;
+	}
+
+	p.size = EC_MEMMAP_TEXT_MAX;
+
+	c = ec_command(EC_CMD_READ_MEMMAP, 0, &p, sizeof(p), dest, p.size);
+	if (c < 0)
+		return c;
+
+	buf = dest;
+	for (c = 0; c < EC_MEMMAP_TEXT_MAX; c++) {
+		if (buf[c] == 0)
+			return c;
+	}
+
+	buf[EC_MEMMAP_TEXT_MAX - 1] = 0;
+	return EC_MEMMAP_TEXT_MAX - 1;
+}
+
+int comm_init(void)
+{
+	/* Default memmap access */
+	ec_readmem = fake_readmem;
+
+	/* Prefer new /dev method */
+	if (comm_init_dev && !comm_init_dev())
+		return 0;
+
+	/* Fallback to direct LPC on x86 */
+	if (comm_init_lpc && !comm_init_lpc())
+		return 0;
+
+	/* Fallback to direct i2c on ARM */
+	if (comm_init_i2c && !comm_init_i2c())
+		return 0;
+
+	/* Give up */
+	fprintf(stderr, "Unable to establish host communication\n");
+	return 1;
+}