From patchwork Tue Jul 10 13:32:16 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Maydell X-Patchwork-Id: 170178 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 59E752C0207 for ; Tue, 10 Jul 2012 23:32:39 +1000 (EST) Received: from localhost ([::1]:56599 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SoaYO-0002Dv-Da for incoming@patchwork.ozlabs.org; Tue, 10 Jul 2012 09:32:36 -0400 Received: from eggs.gnu.org ([208.118.235.92]:56240) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SoaYD-0002Dk-0A for qemu-devel@nongnu.org; Tue, 10 Jul 2012 09:32:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SoaY9-0005Vo-L1 for qemu-devel@nongnu.org; Tue, 10 Jul 2012 09:32:24 -0400 Received: from mnementh.archaic.org.uk ([81.2.115.146]:35558) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SoaY9-0005V2-0N for qemu-devel@nongnu.org; Tue, 10 Jul 2012 09:32:21 -0400 Received: from pm215 by mnementh.archaic.org.uk with local (Exim 4.72) (envelope-from ) id 1SoaY4-00080b-Qn; Tue, 10 Jul 2012 14:32:16 +0100 From: Peter Maydell To: qemu-devel@nongnu.org Date: Tue, 10 Jul 2012 14:32:16 +0100 Message-Id: <1341927136-30762-1-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 1.7.2.5 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Received-From: 81.2.115.146 Cc: Peter Crosthwaite , patches@linaro.org Subject: [Qemu-devel] [PATCH v2] device_tree: Add support for reading device tree properties X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Add support for reading device tree properties (both generic and single-cell ones) to QEMU's convenience wrapper layer. Signed-off-by: Peter Maydell reviewed-by: tag to my v1 patch, then, or was there something --- Here's a v2: * added qemu_devtree_get_one_cell_from_prop() which reads a single cell from a property which is an array of cells * NB that qemu_devtree_getprop() isn't implemented in terms of this because that would give worse error handling. I still think that having this new function is misguided: * nobody's using it * it breaks the current model where functions at the qemu_devtree and libfdt levels deal only with entire properties and do not look inside them to operate on only part of the property value But here's a patch so we can argue about something concrete. device_tree.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ device_tree.h | 6 ++++++ 2 files changed, 55 insertions(+), 0 deletions(-) diff --git a/device_tree.c b/device_tree.c index b366fdd..3a8ff13 100644 --- a/device_tree.c +++ b/device_tree.c @@ -178,6 +178,55 @@ int qemu_devtree_setprop_string(void *fdt, const char *node_path, return r; } +const void *qemu_devtree_getprop(void *fdt, const char *node_path, + const char *property, int *lenp) +{ + int len; + const void *r; + if (!lenp) { + lenp = &len; + } + r = fdt_getprop(fdt, findnode_nofail(fdt, node_path), property, lenp); + if (!r) { + fprintf(stderr, "%s: Couldn't get %s/%s: %s\n", __func__, + node_path, property, fdt_strerror(*lenp)); + exit(1); + } + return r; +} + +uint32_t qemu_devtree_get_one_cell_from_prop(void *fdt, const char *node_path, + const char *property, int idx) +{ + int len; + const uint32_t *p = qemu_devtree_getprop(fdt, node_path, property, &len); + if (len % 4 != 0) { + fprintf(stderr, "%s: %s/%s not multiple of 4 bytes long " + "(not cells?)\n", + __func__, node_path, property); + exit(1); + } + if (len < (idx + 1) * 4) { + fprintf(stderr, "%s: %s/%s wrong length to contain %d cells\n", + __func__, node_path, property, idx + 1); + exit(1); + } + return be32_to_cpu(p[idx]); +} + +uint32_t qemu_devtree_getprop_cell(void *fdt, const char *node_path, + const char *property) +{ + int len; + const uint32_t *p = qemu_devtree_getprop(fdt, node_path, property, &len); + if (len != 4) { + fprintf(stderr, "%s: %s/%s not 4 bytes long (not a cell?)\n", + __func__, node_path, property); + exit(1); + } + return be32_to_cpu(*p); +} + uint32_t qemu_devtree_get_phandle(void *fdt, const char *path) { uint32_t r; diff --git a/device_tree.h b/device_tree.h index 2244270..86669ea 100644 --- a/device_tree.h +++ b/device_tree.h @@ -28,6 +28,12 @@ int qemu_devtree_setprop_string(void *fdt, const char *node_path, int qemu_devtree_setprop_phandle(void *fdt, const char *node_path, const char *property, const char *target_node_path); +const void *qemu_devtree_getprop(void *fdt, const char *node_path, + const char *property, int *lenp); +uint32_t qemu_devtree_getprop_cell(void *fdt, const char *node_path, + const char *property); +uint32_t qemu_devtree_get_one_cell_from_prop(void *fdt, const char *node_path, + const char *property, int idx); uint32_t qemu_devtree_get_phandle(void *fdt, const char *path); uint32_t qemu_devtree_alloc_phandle(void *fdt); int qemu_devtree_nop_node(void *fdt, const char *node_path);