[coreboot-gerrit] Change in coreboot[master]: sconfig: Allow base devicetrees to provide a header

[Angel Pons (Code Review)]

Angel Pons has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/48693 )

Change subject: sconfig: Allow base devicetrees to provide a header
......................................................................

sconfig: Allow base devicetrees to provide a header

To allow mainboards to define macros for use in devicetree, check if
the base devicetree has a corresponding header, and include it from
static.c if it does. Else, do nothing (behaviour remains unchanged).

This assumes that devicetrees end with `.cb` and that their path starts
with `src/`. The header is assumed to not exist if this is not the case.

Change-Id: If9b9908155e64cdc140bb759e1dcc96acb8018b6
Signed-off-by: Angel Pons 
---
M util/sconfig/main.c
1 file changed, 52 insertions(+), 2 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/93/48693/1

diff --git a/util/sconfig/main.c b/util/sconfig/main.c
index 815bfc7..6904a1c 100644
--- a/util/sconfig/main.c
+++ b/util/sconfig/main.c
@@ -1733,6 +1733,55 @@
    override_devicetree(&base_root_bus, dev->bus);
 }

+/* Write an include directive if a header for devtree exists, else do nothing */
+static void emit_devtree_header(FILE *f, const char *devtree)
+{
+	const char prefix[] = "src/";
+	const char old_ext[] = ".cb";
+	const char new_ext[] = ".h";
+	_Static_assert(sizeof(old_ext) >= sizeof(new_ext));
+
+	const char *header = NULL;
+	char *path = NULL;
+
+	if (!devtree)
+		return;
+
+	const size_t old_ext_len = strlen(old_ext);
+	const size_t devtree_len = strlen(devtree);
+	const size_t prefix_len = strlen(prefix);
+
+	/* Ensure preconditions are met */
+	if (devtree_len <= prefix_len + old_ext_len)
+		return;
+
+	path = strdup(devtree);
+	if (!path)
+		return;
+
+	/* Find and replace suffix */
+	char *ext = &path[devtree_len - old_ext_len];
+	if (strncmp(ext, old_ext, old_ext_len))
+		goto out;
+
+	strcpy(ext, new_ext);
+	assert(strlen(path) - strlen(new_ext) == devtree_len - old_ext_len);
+
+	/* Check if file actually exists */
+	struct stat st;
+	if ((stat(path, &st) == -1) && (errno == ENOENT))
+		goto out;
+
+	/* Remove the prefix */
+	if (strncmp(path, prefix, prefix_len))
+		goto out;
+
+	fprintf(f, "#include <%s>\n", &path[prefix_len]);
+
+out:
+	free(path);
+}
+
 static void generate_outputh(FILE *f, const char *fw_conf_header, const char *device_header)
 {
    fprintf(f, "#ifndef __STATIC_DEVICE_TREE_H\n");
@@ -1744,12 +1793,13 @@
    fprintf(f, "\n#endif /* __STATIC_DEVICE_TREE_H */\n");
 }

-static void generate_outputc(FILE *f, const char *static_header)
+static void generate_outputc(FILE *f, const char *static_header, const char *base_devtree)
 {
    fprintf(f, "#include <device/device.h>\n");
    fprintf(f, "#include <device/pci.h>\n");
    fprintf(f, "#include <fw_config.h>\n");
    fprintf(f, "#include <%s>\n", static_header);
+	emit_devtree_header(f, base_devtree);
    emit_chip_headers(f, chip_header.next);
    fprintf(f, "\n#define STORAGE static __unused DEVTREE_CONST\n\n");

@@ -1895,7 +1945,7 @@
    const char *static_header = basename(h);

generate_outputh(autohead, fw_conf_header, device_header);
-	generate_outputc(autogen, static_header);
+	generate_outputc(autogen, static_header, base_devtree);
    generate_outputd(autogen, autodev);
    generate_outputf(autofwconf);