From 0ffe265fd969f5ac689c820a4b40a99cd2f1e9a9 Mon Sep 17 00:00:00 2001 From: Samuel Holland Date: Wed, 19 Feb 2025 12:42:51 -0800 Subject: [PATCH] lib: utils/fdt: Respect compatible string fallback priority When matching drivers to DT nodes, always match all drivers against the first compatible string before considering fallback compatible strings. This ensures the most specific match is always selected, regardless of the order of the drivers or match structures, as long as no compatible string appears in multiple match structures. Fixes: 1ccc52c427f3 ("lib: utils/fdt: Add helpers for generic driver initialization") Signed-off-by: Samuel Holland Reviewed-by: Anup Patel --- lib/utils/fdt/fdt_driver.c | 50 ++++++++++++++++++++------------------ 1 file changed, 27 insertions(+), 23 deletions(-) diff --git a/lib/utils/fdt/fdt_driver.c b/lib/utils/fdt/fdt_driver.c index f6707c0e..39385ce9 100644 --- a/lib/utils/fdt/fdt_driver.c +++ b/lib/utils/fdt/fdt_driver.c @@ -15,39 +15,43 @@ int fdt_driver_init_by_offset(const void *fdt, int nodeoff, { const struct fdt_driver *driver; const struct fdt_match *match; - const void *prop; - int len, rc; + int compat_len, prop_len, rc; + const char *compat_str; if (!fdt_node_is_enabled(fdt, nodeoff)) return SBI_ENODEV; - prop = fdt_getprop(fdt, nodeoff, "compatible", &len); - if (!prop) + compat_str = fdt_getprop(fdt, nodeoff, "compatible", &prop_len); + if (!compat_str) return SBI_ENODEV; - while ((driver = *drivers++)) { - for (match = driver->match_table; match->compatible; match++) { - if (!fdt_stringlist_contains(prop, len, match->compatible)) - continue; + while ((compat_len = strnlen(compat_str, prop_len) + 1) <= prop_len) { + for (int i = 0; (driver = drivers[i]); i++) + for (match = driver->match_table; match->compatible; match++) + if (!memcmp(match->compatible, compat_str, compat_len)) + goto found; - if (driver->experimental) - sbi_printf("WARNING: %s driver is experimental and may change\n", - match->compatible); - - rc = driver->init(fdt, nodeoff, match); - if (rc < 0) { - const char *name; - - name = fdt_get_name(fdt, nodeoff, NULL); - sbi_printf("%s: %s (%s) init failed: %d\n", - __func__, name, match->compatible, rc); - } - - return rc; - } + compat_str += compat_len; + prop_len -= compat_len; } return SBI_ENODEV; + +found: + if (driver->experimental) + sbi_printf("WARNING: %s driver is experimental and may change\n", + match->compatible); + + rc = driver->init(fdt, nodeoff, match); + if (rc < 0) { + const char *name; + + name = fdt_get_name(fdt, nodeoff, NULL); + sbi_printf("%s: %s (%s) init failed: %d\n", + __func__, name, match->compatible, rc); + } + + return rc; } static int fdt_driver_init_scan(const void *fdt,