From nobody Tue Feb 10 04:03:35 2026 Received: from smtpout-02.galae.net (smtpout-02.galae.net [185.246.84.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EA5B5315D2A; Wed, 7 Jan 2026 13:05:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.84.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767791122; cv=none; b=XyRCCZow3VArHhA+T4dQx+qQsYP0yQpx2vYfLTJOZUN6uSz1T/JcEeZqNXet1V+HIOw7Wa2dI5RaKyJgTUhnlk3xC2yDOlm0jJ1fkMnq621s3ipMNrIKUnhR/Naeojz3smYC1HM4XJkxRoeUrnLj11Oak21FTGejNrGyMpOqun8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767791122; c=relaxed/simple; bh=yTyrj5QoFsGABNaD50sMrBTfi0UxSYpQmgtQqsF91IQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=V5/KvTbiZp+y13wTWVOAgggg9VSYQ4bhJB4Ksepk3aQvF+GBcGn6/L1T+UruMhg8IekCjFL6rYWtQiQLAQpNnJjGCk1ulmr8a8LUX9b5s6IxrFjiQylnxq1L0iUCjsnqoSaUhKonZnBBzd2JvXzzbRVmnMgJFXoT2r/PQN23bm8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=UuENz/RQ; arc=none smtp.client-ip=185.246.84.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="UuENz/RQ" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id 7F3D71A26CD; Wed, 7 Jan 2026 13:05:18 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 552FB606F8; Wed, 7 Jan 2026 13:05:18 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 087BF103C873B; Wed, 7 Jan 2026 14:05:15 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1767791117; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=XMo0yKviCSls+Xrv3kwTnjITS8GQtx4OexQnCkfHofE=; b=UuENz/RQwtv9wgkzp85Tr6QLFxQOs22jCliOiild6uFJD47o64iojbXqggSC2Xp+FGTAIK xOJe36VxoJ7UQezuQrBpnmBXIPXugHhTltZPcrEliN54Uv5KDE/i7k/PTYx7gWszNhDCsz BjmBYJ0tVs/Jp25SUJ2U65+iD1S/5qA6wcmctOsb/wvZ9lKSM3P5R0fe+kBd3V2wnA38F2 XdShzZWO+EqWf1mAim3q+LglcI/G9iOeEJDDiBZqLxEkCzViMEqH/gS6e9aSgR7anZCwcG GltrftUgbGWUzZLGzN/z6QZtOE49aqcauTVB7bDAXJ88wELVqUkqnaSQj6wKAw== From: Gregory CLEMENT Date: Wed, 07 Jan 2026 14:04:53 +0100 Subject: [PATCH v3 2/4] of: reserved_mem: Support multiple 'reg' entries for memory-region Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260107-mtd-memregion-v3-2-f9fc9107b992@bootlin.com> References: <20260107-mtd-memregion-v3-0-f9fc9107b992@bootlin.com> In-Reply-To: <20260107-mtd-memregion-v3-0-f9fc9107b992@bootlin.com> To: Rob Herring , Linus Walleij , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Krzysztof Kozlowski , Conor Dooley Cc: Thomas Petazzoni , Vladimir Kondratiev , =?utf-8?q?Beno=C3=AEt_Monin?= , =?utf-8?q?Th=C3=A9o_Lebrun?= , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mtd@lists.infradead.org, Gregory CLEMENT X-Mailer: b4 0.14.3 X-Last-TLS-Session-Version: TLSv1.3 X-Rspamd-Fuzzy: 4424144f4218900c354d6490f15d7fd89bd74a90c2a7348481eaef86083880102d8c77ac236285b683c0bd37638dc6a3f0301a0bc431696a6ae2fe169c719249 The Device Tree specification allows a "memory-region" node to have multiple 'reg' entries, but the current kernel implementation only processes the first entry. This can lead to drivers not being able to access all the reserved memory regions specified in the Device Tree. This patch extends the reserved memory handling to support multiple 'reg' entries for a single "memory-region" node. The existing exported functions remain unchanged for backward compatibility, but new APIs are introduced to allow drivers to access all reserved memory regions. Signed-off-by: Gregory CLEMENT --- drivers/of/of_reserved_mem.c | 147 ++++++++++++++++++++++++++++++++++++= ---- include/linux/of_reserved_mem.h | 4 ++ 2 files changed, 137 insertions(+), 14 deletions(-) diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index 1ab8f4153600b..c9cef279260e7 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -157,6 +157,7 @@ static int __init __reserved_mem_reserve_reg(unsigned l= ong node, int i, len; const __be32 *prop; bool nomap; + int count =3D 0; =20 prop =3D of_flat_dt_get_addr_size_prop(node, "reg", &len); if (!prop) @@ -179,12 +180,13 @@ static int __init __reserved_mem_reserve_reg(unsigned= long node, dma_contiguous_early_fixup(base, size); pr_debug("Reserved memory: reserved region for node '%s': base %pa, siz= e %lu MiB\n", uname, &base, (unsigned long)(size / SZ_1M)); + count++; } else { pr_err("Reserved memory: failed to reserve memory for node '%s': base %= pa, size %lu MiB\n", uname, &base, (unsigned long)(size / SZ_1M)); } } - return 0; + return count; } =20 /* @@ -247,20 +249,24 @@ void __init fdt_scan_reserved_mem_reg_nodes(void) =20 fdt_for_each_subnode(child, fdt, node) { const char *uname; + const __be32 *reg; u64 b, s; + int i, l; =20 if (!of_fdt_device_is_available(fdt, child)) continue; - - if (!of_flat_dt_get_addr_size(child, "reg", &b, &s)) + reg =3D of_flat_dt_get_addr_size_prop(child, "reg", &l); + if (!reg) continue; - - base =3D b; - size =3D s; - - if (size) { - uname =3D fdt_get_name(fdt, child, NULL); - fdt_reserved_mem_save_node(child, uname, base, size); + for (i =3D 0; i < l; i++) { + of_flat_dt_read_addr_size(reg, i, &b, &s); + base =3D b; + size =3D s; + + if (size) { + uname =3D fdt_get_name(fdt, child, NULL); + fdt_reserved_mem_save_node(child, uname, base, size); + } } } =20 @@ -291,16 +297,16 @@ int __init fdt_scan_reserved_mem(void) =20 fdt_for_each_subnode(child, fdt, node) { const char *uname; - int err; + int err, ret; =20 if (!of_fdt_device_is_available(fdt, child)) continue; =20 uname =3D fdt_get_name(fdt, child, NULL); =20 - err =3D __reserved_mem_reserve_reg(child, uname); - if (!err) - count++; + ret =3D __reserved_mem_reserve_reg(child, uname); + if (ret > 0) + count +=3D ret; /* * Save the nodes for the dynamically-placed regions * into an array which will be used for allocation right @@ -726,6 +732,35 @@ struct reserved_mem *of_reserved_mem_lookup(struct dev= ice_node *np) } EXPORT_SYMBOL_GPL(of_reserved_mem_lookup); =20 +/** + * of_reserved_mem_array_lookup() - acquire reserved_mem array from a devi= ce node + * @np: node pointer of the desired reserved-memory region + * @rmrm: pointer to the first elemennt of the reserved_mem struct of the = memory region + * + * This function allows drivers to acquire a reference to the array of the + * reserved_mem struct based on a device node handle. + * + * Returns the number reserved_mem elements + */ +int of_reserved_mem_array_lookup(struct device_node *np, + struct reserved_mem **rmem) +{ + const char *name; + int i, count =3D 0; + + if (!np->full_name) + return 0; + + name =3D kbasename(np->full_name); + + for (i =3D 0; i < reserved_mem_count; i++) + if (!strcmp(reserved_mem[i].name, name)) + rmem[count++] =3D &reserved_mem[i]; + + return count; +} +EXPORT_SYMBOL_GPL(of_reserved_mem_array_lookup); + /** * of_reserved_mem_region_to_resource() - Get a reserved memory region as = a resource * @np: node containing 'memory-region' property @@ -761,6 +796,49 @@ int of_reserved_mem_region_to_resource(const struct de= vice_node *np, } EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource); =20 +/** + * of_reserved_mem_region_to_resource_array() - Get a reserved memory regi= on as a resources + * @dev: device associated to the node + * @np: node containing 'memory-region' property + * @idx: index of 'memory-region' property to lookup + * @res: Pointer to an array of struct resource pointers to fill in with r= eserved regions + * + * This function allows drivers to lookup a node's 'memory-region' property + * entries by index and fill an array of struct resource pointers for the = entries. + * + * Returns the number of resources filled in @res on success. + * Returns -ENODEV if 'memory-region' is missing or unavailable, + * -EINVAL for any other error. + */ +int of_reserved_mem_region_to_resource_array(struct device *dev, const str= uct device_node *np, + unsigned int idx, struct resource **res) +{ + struct reserved_mem *rmem[MAX_RESERVED_REGIONS]; + int count, i; + struct resource *r; + + if (!np) + return -EINVAL; + + struct device_node *target __free(device_node) =3D of_parse_phandle(np, "= memory-region", idx); + if (!target || !of_device_is_available(target)) + return -ENODEV; + + count =3D of_reserved_mem_array_lookup(target, rmem); + if (count <=3D 0) + return -EINVAL; + + *res =3D devm_kzalloc(dev, count * sizeof(struct resource), GFP_KERNEL); + r =3D res[0]; + for (i =3D 0; i < count; i++) { + resource_set_range(&r[i], rmem[i]->base, rmem[i]->size); + r[i].flags =3D IORESOURCE_MEM; + r[i].name =3D rmem[i]->name; + } + return count; +} +EXPORT_SYMBOL_GPL(of_reserved_mem_region_to_resource_array); + /** * of_reserved_mem_region_to_resource_byname() - Get a reserved memory reg= ion as a resource * @np: node containing 'memory-region' property @@ -805,3 +883,44 @@ int of_reserved_mem_region_count(const struct device_n= ode *np) return of_count_phandle_with_args(np, "memory-region", NULL); } EXPORT_SYMBOL_GPL(of_reserved_mem_region_count); + +/** + * of_reserved_mem_region_count() - Return the total number of reserved me= mory regions + * @np: node containing 'memory-region' property + * + * This function counts the total number of reserved memory regions refere= nced + * by a node's 'memory-region' property. It iterates over each phandle and= sums + * the number of regions found in each referenced reserved memory node. + * + * Returns the total number of reserved memory regions on success. + * This function allows drivers to retrieve the number of entries for a no= de's + * 'memory-region' property. + * + * Returns total number of reserved memory regions on success, or negative= error + * code on a malformed property. + */ +int of_reserved_mem_region_total_count(const struct device_node *np) +{ + int nregion =3D of_count_phandle_with_args(np, "memory-region", NULL); + struct device_node *target; + int i, nregs =3D 0; + + for (i =3D 0; i < nregion; i++) { + struct reserved_mem *rmem; + + target =3D of_parse_phandle(np, "memory-region", i); + if (!target) + return -ENODEV; + + if (!of_device_is_available(target)) { + of_node_put(target); + return 0; + } + + nregs +=3D of_reserved_mem_array_lookup(target, &rmem); + + of_node_put(target); + }; + return nregs; +} +EXPORT_SYMBOL_GPL(of_reserved_mem_region_total_count); diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_me= m.h index f573423359f48..1e0c6afddd812 100644 --- a/include/linux/of_reserved_mem.h +++ b/include/linux/of_reserved_mem.h @@ -40,11 +40,15 @@ int of_reserved_mem_device_init_by_name(struct device *= dev, void of_reserved_mem_device_release(struct device *dev); =20 struct reserved_mem *of_reserved_mem_lookup(struct device_node *np); +int of_reserved_mem_array_lookup(struct device_node *np, struct reserved_m= em **rmem); int of_reserved_mem_region_to_resource(const struct device_node *np, unsigned int idx, struct resource *res); +int of_reserved_mem_region_to_resource_array(struct device *dev, const str= uct device_node *np, + unsigned int idx, struct resource **res); int of_reserved_mem_region_to_resource_byname(const struct device_node *np, const char *name, struct resource *res); int of_reserved_mem_region_count(const struct device_node *np); +int of_reserved_mem_region_total_count(const struct device_node *np); =20 #else =20 --=20 2.51.0