{"id":2198193,"url":"http://patchwork.ozlabs.org/api/1.0/patches/2198193/?format=json","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.0/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260219143332.3316679-3-ruslichenko.r@gmail.com>","date":"2026-02-19T14:33:01","name":"[v2,02/33] system/device_tree: add few parsing and traversal helpers","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"bfca13b9e334d7672d2d523e1f6c7add95c835a4","submitter":{"id":92275,"url":"http://patchwork.ozlabs.org/api/1.0/people/92275/?format=json","name":"Ruslan Ruslichenko","email":"ruslichenko.r@gmail.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260219143332.3316679-3-ruslichenko.r@gmail.com/mbox/","series":[{"id":492690,"url":"http://patchwork.ozlabs.org/api/1.0/series/492690/?format=json","date":"2026-02-19T14:33:04","name":"hw/arm: Introduce generic FDT-driven machine","version":2,"mbox":"http://patchwork.ozlabs.org/series/492690/mbox/"}],"check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2198193/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20230601 header.b=EN2JNFGW;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fGwsN5rb0z1xxQ\n\tfor ; Fri, 20 Feb 2026 01:35:36 +1100 (AEDT)","from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from )\n\tid 1vt576-0008Sl-Q9; Thu, 19 Feb 2026 09:34:44 -0500","from eggs.gnu.org ([2001:470:142:3::10])\n by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from )\n id 1vt575-0008Rc-FN\n for qemu-devel@nongnu.org; Thu, 19 Feb 2026 09:34:43 -0500","from mail-wr1-x42b.google.com ([2a00:1450:4864:20::42b])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128)\n (Exim 4.90_1) (envelope-from )\n id 1vt573-0002uf-Fc\n for qemu-devel@nongnu.org; Thu, 19 Feb 2026 09:34:43 -0500","by mail-wr1-x42b.google.com with SMTP id\n ffacd0b85a97d-43945763558so631832f8f.3\n for ; Thu, 19 Feb 2026 06:34:41 -0800 (PST)","from thinkpad-t470s.. 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Iglesias\" ,\n Ruslan_Ruslichenko@epam.com, balaton@eik.bme.hu,\n Alistair Francis ,\n David Gibson ","Subject":"[PATCH v2 02/33] system/device_tree: add few parsing and traversal\n helpers","Date":"Thu, 19 Feb 2026 15:33:01 +0100","Message-ID":"<20260219143332.3316679-3-ruslichenko.r@gmail.com>","X-Mailer":"git-send-email 2.43.0","In-Reply-To":"<20260219143332.3316679-1-ruslichenko.r@gmail.com>","References":"<20260219143332.3316679-1-ruslichenko.r@gmail.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Received-SPF":"pass client-ip=2a00:1450:4864:20::42b;\n envelope-from=ruslichenko.r@gmail.com; helo=mail-wr1-x42b.google.com","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"From: Ruslan Ruslichenko \n\nThe patch adds few utility functions for parsing FDT nodes.\nThe helpers are required for upcoming Hardware device tree\nfeature.\n\nSigned-off-by: Ruslan Ruslichenko \n---\n include/system/device_tree.h | 30 +++++\n system/device_tree.c | 221 +++++++++++++++++++++++++++++++++++\n 2 files changed, 251 insertions(+)","diff":"diff --git a/include/system/device_tree.h b/include/system/device_tree.h\nindex 5667ff9538..9d6b570bdb 100644\n--- a/include/system/device_tree.h\n+++ b/include/system/device_tree.h\n@@ -116,6 +116,11 @@ const void *qemu_fdt_getprop(void *fdt, const char *node_path,\n uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,\n const char *property, int cell_id,\n Error **errp);\n+\n+const void *qemu_fdt_getprop_inherited(void *fdt, const char *node_path,\n+ const char *property, int *lenp, Error **errp);\n+uint32_t qemu_fdt_getprop_cell_inherited(void *fdt, const char *node_path,\n+ const char *property, int cell_id, Error **errp);\n uint32_t qemu_fdt_get_phandle(void *fdt, const char *path);\n uint32_t qemu_fdt_alloc_phandle(void *fdt);\n int qemu_fdt_nop_node(void *fdt, const char *node_path);\n@@ -191,6 +196,31 @@ int qemu_fdt_setprop_sized_cells_from_array(void *fdt,\n qdt_tmp); \\\n })\n \n+typedef struct QEMUDevtreeProp {\n+ const char *name;\n+ int len;\n+ const void *value;\n+} QEMUDevtreeProp;\n+\n+/* node queries */\n+\n+int qemu_devtree_get_num_children(void *fdt, const char *node_path);\n+int qemu_devtree_get_children(void *fdt, const char *node_path,\n+ int max_paths, char **returned_paths);\n+int qemu_devtree_num_props(void *fdt, const char *node_path);\n+QEMUDevtreeProp *qemu_devtree_get_props(void *fdt, const char *node_path);\n+\n+/* node getters */\n+\n+int qemu_devtree_get_node_by_phandle(void *fdt, char *node_path, int phandle);\n+int qemu_devtree_getparent(void *fdt, char *node_path,\n+ const char *current);\n+\n+/* misc */\n+\n+int devtree_get_num_nodes(void *fdt);\n+\n+#define DT_PATH_LENGTH 1024\n \n /**\n * qemu_fdt_randomize_seeds:\ndiff --git a/system/device_tree.c b/system/device_tree.c\nindex d2db7bd355..fc34c660db 100644\n--- a/system/device_tree.c\n+++ b/system/device_tree.c\n@@ -464,6 +464,103 @@ uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,\n return be32_to_cpu(p[cell_id]);\n }\n \n+const void *qemu_fdt_getprop_inherited(void *fdt, const char *node_path,\n+ const char *property, int *lenp, Error **errp)\n+{\n+ const void *found_val = NULL;\n+ int found_len = 0;\n+ int curr_offset = 0;\n+ int temp_len;\n+ char **tokens;\n+ char **iter;\n+\n+ found_val = fdt_getprop(fdt, 0, property, &found_len);\n+\n+ tokens = g_strsplit(node_path + 1, \"/\", -1);\n+\n+ for (iter = tokens; *iter != NULL; iter++) {\n+ if (**iter == '\\0') {\n+ continue;\n+ }\n+\n+ curr_offset = fdt_subnode_offset(fdt, curr_offset, *iter);\n+ if (curr_offset < 0) {\n+ error_setg(errp, \"%s: Path '%s' not found\",\n+ __func__, *iter);\n+ g_strfreev(tokens);\n+ return NULL;\n+ }\n+\n+ const void *val = fdt_getprop(fdt, curr_offset, property, &temp_len);\n+ if (val) {\n+ found_val = val;\n+ found_len = temp_len;\n+ }\n+ }\n+ g_strfreev(tokens);\n+\n+ if (!found_val) {\n+ error_setg(errp, \"%s: Property '%s' not found\",\n+ __func__, property);\n+ return NULL;\n+ }\n+\n+ if (lenp) {\n+ *lenp = found_len;\n+ }\n+\n+ return found_val;\n+}\n+\n+uint32_t qemu_fdt_getprop_cell_inherited(void *fdt, const char *node_path,\n+ const char *property, int cell_id, Error **errp)\n+{\n+ int len;\n+ const uint32_t *p;\n+\n+ p = qemu_fdt_getprop_inherited(fdt, node_path, property, &len, errp);\n+ if (!p) {\n+ return 0;\n+ }\n+ if (len < (cell_id + 1) * 4) {\n+ error_setg(errp,\n+ \"%s: %s/%s is too short, need %d bytes for cell ind %d\",\n+ __func__, node_path, property, (cell_id + 1) * 4, cell_id);\n+ return 0;\n+ }\n+ return be32_to_cpu(p[cell_id]);\n+}\n+\n+int qemu_devtree_getparent(void *fdt, char *node_path, const char *current)\n+{\n+ const char *sep;\n+ int len;\n+\n+ if (!current || !node_path) {\n+ return -FDT_ERR_NOTFOUND;\n+ }\n+\n+ if (current[0] == '/' && current[1] == 0) {\n+ return -FDT_ERR_NOTFOUND;\n+ }\n+\n+ sep = strrchr(current, '/');\n+ if (!sep) {\n+ return -FDT_ERR_BADPATH;\n+ }\n+\n+ if (sep == current) {\n+ len = 1;\n+ } else {\n+ len = sep - current;\n+ }\n+\n+ memcpy(node_path, current, len);\n+ node_path[len] = '\\0';\n+\n+ return 0;\n+}\n+\n uint32_t qemu_fdt_get_phandle(void *fdt, const char *path)\n {\n uint32_t r;\n@@ -631,6 +728,130 @@ out:\n return ret;\n }\n \n+int qemu_devtree_num_props(void *fdt, const char *node_path)\n+{\n+ int offset = fdt_path_offset(fdt, node_path);\n+ int ret = 0;\n+\n+ for (offset = fdt_first_property_offset(fdt, offset);\n+ offset != -FDT_ERR_NOTFOUND;\n+ offset = fdt_next_property_offset(fdt, offset)) {\n+ ret++;\n+ }\n+ return ret;\n+}\n+\n+QEMUDevtreeProp *qemu_devtree_get_props(void *fdt, const char *node_path)\n+{\n+ QEMUDevtreeProp *ret = g_new0(QEMUDevtreeProp,\n+ qemu_devtree_num_props(fdt, node_path) + 1);\n+ int offset = fdt_path_offset(fdt, node_path);\n+ int i = 0;\n+\n+ for (offset = fdt_first_property_offset(fdt, offset);\n+ offset != -FDT_ERR_NOTFOUND;\n+ offset = fdt_next_property_offset(fdt, offset)) {\n+ const char *propname;\n+ const void *val = fdt_getprop_by_offset(fdt, offset, &propname,\n+ &ret[i].len);\n+\n+ ret[i].name = propname;\n+ ret[i].value = val;\n+ i++;\n+ }\n+ return ret;\n+}\n+\n+int qemu_devtree_get_children(void *fdt, const char *node_path,\n+ int max_paths, char **returned_paths) {\n+ int count = 0;\n+ int subnode;\n+ const char *name;\n+ int offset = fdt_path_offset(fdt, node_path);\n+\n+ if (offset < 0) {\n+ return offset;\n+ }\n+\n+ bool is_root = (strcmp(node_path, \"/\") == 0);\n+\n+ fdt_for_each_subnode(subnode, fdt, offset) {\n+ if (count >= max_paths) {\n+ break;\n+ }\n+ name = fdt_get_name(fdt, subnode, NULL);\n+ if (returned_paths) {\n+ returned_paths[count] = g_strdup_printf(\"%s/%s\",\n+ is_root ? \"\" : node_path, name);\n+ }\n+\n+ ++count;\n+ }\n+\n+ return count;\n+}\n+\n+int qemu_devtree_get_num_children(void *fdt, const char *node_path)\n+{\n+ int count = 0;\n+ int subnode;\n+ int offset = fdt_path_offset(fdt, node_path);\n+\n+ if (offset < 0) {\n+ return offset;\n+ }\n+\n+ fdt_for_each_subnode(subnode, fdt, offset) {\n+ ++count;\n+ }\n+\n+ return count;\n+}\n+\n+int qemu_devtree_get_node_by_phandle(void *fdt, char *node_path, int phandle)\n+{\n+ int offset = 0, cur_depth = 0;\n+ int path_lens[64] = { 0 };\n+\n+ for (offset = 0; offset >= 0; offset = fdt_next_node(fdt, offset,\n+ &cur_depth)) {\n+ if (cur_depth > 64) {\n+ break;\n+ }\n+ const char *name = fdt_get_name(fdt, offset, NULL);\n+\n+ int parent_len = (cur_depth > 0) ? path_lens[cur_depth - 1] : 0;\n+ int len = snprintf(node_path + parent_len,\n+ DT_PATH_LENGTH - parent_len,\n+ \"%s%s\",\n+ (parent_len > 1) ? \"/\" : \"\",\n+ (cur_depth == 0) ? \"/\" : name);\n+\n+ path_lens[cur_depth] = parent_len + len;\n+\n+ if (fdt_get_phandle(fdt, offset) == phandle) {\n+ return 0;\n+ }\n+ }\n+\n+ return -FDT_ERR_NOTFOUND;\n+}\n+\n+int devtree_get_num_nodes(void *fdt)\n+{\n+ int num_nodes = 0;\n+ int depth = 0, offset = 0;\n+\n+ for (;;) {\n+ offset = fdt_next_node(fdt, offset, &depth);\n+ num_nodes++;\n+ if (offset <= 0 || depth <= 0) {\n+ break;\n+ }\n+ }\n+ return num_nodes;\n+}\n+\n void qmp_dumpdtb(const char *filename, Error **errp)\n {\n ERRP_GUARD();\n","prefixes":["v2","02/33"]}