From nobody Sat Dec 27 05:13:36 2025 Received: from mail.tkos.co.il (hours.tkos.co.il [84.110.109.230]) (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 3EC5E4595B; Wed, 27 Dec 2023 15:12:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=tkos.co.il Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=tkos.co.il Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=tkos.co.il header.i=@tkos.co.il header.b="NDqdcjcT" Received: from tarshish.tkos.co.il (unknown [10.0.8.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.tkos.co.il (Postfix) with ESMTPS id 43D39440F19; Wed, 27 Dec 2023 17:02:43 +0200 (IST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tkos.co.il; s=default; t=1703689363; bh=NDjhIXrijySlyAenotxkN/N6ucKkMmhIuT0+ciVsprY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NDqdcjcTK2m+7XK61ZGidZ5CHtBbiSX38xo6izGJCY26bma2wq7IBWT4vz000eUw1 GBbwyf7OQe+WaevbOBXI+5vavzS5FexuGsu1cTgMYyNCTp1yxO8Kx5jqkppNWa6Z8j G/94uSrvb6kFeiuJzbR3wWgZFMCTFEAZXRRD5jqHa1q3iQwABRitbkrY3IBwFqBRM9 ZlogSwyK6XNcbZ5B6kSPEuHxCz0+ItVYTRfoquADxy8KvWxqqP11b4ScQU54jhnxXU S5X08TEbiHVEdcVcv7WEld7Zmelmi5aa6tL4Gh5BrEponHpbVWgdEmUQ1qNIAqcQTZ dZT3UDYjbT/8A== From: Baruch Siach To: Christoph Hellwig , Marek Szyprowski , Rob Herring , Frank Rowand , Catalin Marinas , Will Deacon Cc: Baruch Siach , Robin Murphy , iommu@lists.linux.dev, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Petr=20Tesa=C5=99=C3=ADk?= , Ramon Fried Subject: [PATCH RFC 1/4] of: get dma area lower limit Date: Wed, 27 Dec 2023 17:04:25 +0200 Message-ID: X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" of_dma_get_max_cpu_address() returns the highest CPU address that devices can use for DMA. The implicit assumption is that all CPU addresses below that limit are suitable for DMA. However the 'dma-ranges' property this code uses also encodes a lower limit for DMA that is potentially non zero. Rename to of_dma_get_cpu_limits(), and extend to retrieve also the lower limit for the same 'dma-ranges' property describing the high limit. Update callers of of_dma_get_max_cpu_address(). No functional change intended. Signed-off-by: Baruch Siach --- arch/arm64/mm/init.c | 4 +++- drivers/of/address.c | 38 +++++++++++++++++++++++++++----------- drivers/of/unittest.c | 8 ++++---- include/linux/of.h | 11 ++++++++--- 4 files changed, 42 insertions(+), 19 deletions(-) diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 74c1db8ce271..d6c723ae6fb0 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -136,11 +136,13 @@ static void __init zone_sizes_init(void) unsigned long max_zone_pfns[MAX_NR_ZONES] =3D {0}; unsigned int __maybe_unused acpi_zone_dma_bits; unsigned int __maybe_unused dt_zone_dma_bits; + phys_addr_t __maybe_unused max_cpu_address; phys_addr_t __maybe_unused dma32_phys_limit =3D max_zone_phys(32); =20 #ifdef CONFIG_ZONE_DMA acpi_zone_dma_bits =3D fls64(acpi_iort_dma_get_max_cpu_address()); - dt_zone_dma_bits =3D fls64(of_dma_get_max_cpu_address(NULL)); + of_dma_get_cpu_limits(NULL, &max_cpu_address, NULL); + dt_zone_dma_bits =3D fls64(max_cpu_address); zone_dma_bits =3D min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits); arm64_dma_phys_limit =3D max_zone_phys(zone_dma_bits); max_zone_pfns[ZONE_DMA] =3D PFN_DOWN(arm64_dma_phys_limit); diff --git a/drivers/of/address.c b/drivers/of/address.c index b59956310f66..51fa52bbe911 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c @@ -965,21 +965,25 @@ int of_dma_get_range(struct device_node *np, const st= ruct bus_dma_region **map) #endif /* CONFIG_HAS_DMA */ =20 /** - * of_dma_get_max_cpu_address - Gets highest CPU address suitable for DMA + * of_dma_get_cpu_limits - Gets highest CPU address suitable for DMA * @np: The node to start searching from or NULL to start from the root + * @max: Pointer to high address limit or NULL if not needed + * @min: Pointer to low address limit or NULL if not needed * * Gets the highest CPU physical address that is addressable by all DMA ma= sters - * in the sub-tree pointed by np, or the whole tree if NULL is passed. If = no - * DMA constrained device is found, it returns PHYS_ADDR_MAX. + * in the sub-tree pointed by np, or the whole tree if @np in NULL. If no + * DMA constrained device is found, @*max is PHYS_ADDR_MAX, and @*low is 0. */ -phys_addr_t __init of_dma_get_max_cpu_address(struct device_node *np) +void __init of_dma_get_cpu_limits(struct device_node *np, + phys_addr_t *max, phys_addr_t *min) { phys_addr_t max_cpu_addr =3D PHYS_ADDR_MAX; struct of_range_parser parser; - phys_addr_t subtree_max_addr; + phys_addr_t min_cpu_addr =3D 0; struct device_node *child; struct of_range range; const __be32 *ranges; + u64 cpu_start =3D 0; u64 cpu_end =3D 0; int len; =20 @@ -989,21 +993,33 @@ phys_addr_t __init of_dma_get_max_cpu_address(struct = device_node *np) ranges =3D of_get_property(np, "dma-ranges", &len); if (ranges && len) { of_dma_range_parser_init(&parser, np); - for_each_of_range(&parser, &range) - if (range.cpu_addr + range.size > cpu_end) + for_each_of_range(&parser, &range) { + if (range.cpu_addr + range.size > cpu_end) { cpu_end =3D range.cpu_addr + range.size - 1; + cpu_start =3D range.cpu_addr; + } + } =20 - if (max_cpu_addr > cpu_end) + if (max_cpu_addr > cpu_end) { max_cpu_addr =3D cpu_end; + min_cpu_addr =3D cpu_start; + } } =20 for_each_available_child_of_node(np, child) { - subtree_max_addr =3D of_dma_get_max_cpu_address(child); - if (max_cpu_addr > subtree_max_addr) + phys_addr_t subtree_max_addr, subtree_min_addr; + + of_dma_get_cpu_limits(child, &subtree_max_addr, &subtree_min_addr); + if (max_cpu_addr > subtree_max_addr) { max_cpu_addr =3D subtree_max_addr; + min_cpu_addr =3D subtree_min_addr; + } } =20 - return max_cpu_addr; + if (max) + *max =3D max_cpu_addr; + if (min) + *min =3D min_cpu_addr; } =20 /** diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c index e9e90e96600e..21d273a05ba6 100644 --- a/drivers/of/unittest.c +++ b/drivers/of/unittest.c @@ -908,7 +908,7 @@ static void __init of_unittest_changeset(void) #endif } =20 -static void __init of_unittest_dma_get_max_cpu_address(void) +static void __init of_unittest_dma_get_cpu_limits(void) { struct device_node *np; phys_addr_t cpu_addr; @@ -922,9 +922,9 @@ static void __init of_unittest_dma_get_max_cpu_address(= void) return; } =20 - cpu_addr =3D of_dma_get_max_cpu_address(np); + of_dma_get_cpu_limits(np, &cpu_addr, NULL); unittest(cpu_addr =3D=3D 0x4fffffff, - "of_dma_get_max_cpu_address: wrong CPU addr %pad (expecting %x)\n", + "of_dma_get_cpu_limits: wrong CPU addr %pad (expecting %x)\n", &cpu_addr, 0x4fffffff); } =20 @@ -4104,7 +4104,7 @@ static int __init of_unittest(void) of_unittest_changeset(); of_unittest_parse_interrupts(); of_unittest_parse_interrupts_extended(); - of_unittest_dma_get_max_cpu_address(); + of_unittest_dma_get_cpu_limits(); of_unittest_parse_dma_ranges(); of_unittest_pci_dma_ranges(); of_unittest_bus_ranges(); diff --git a/include/linux/of.h b/include/linux/of.h index 6a9ddf20e79a..629b402d81bf 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -445,7 +445,8 @@ int of_map_id(struct device_node *np, u32 id, const char *map_name, const char *map_mask_name, struct device_node **target, u32 *id_out); =20 -phys_addr_t of_dma_get_max_cpu_address(struct device_node *np); +void of_dma_get_cpu_limits(struct device_node *np, phys_addr_t *max, + phys_addr_t *min); =20 struct kimage; void *of_kexec_alloc_and_setup_fdt(const struct kimage *image, @@ -865,9 +866,13 @@ static inline int of_map_id(struct device_node *np, u3= 2 id, return -EINVAL; } =20 -static inline phys_addr_t of_dma_get_max_cpu_address(struct device_node *n= p) +static inline void of_dma_get_cpu_limits(struct device_node *np, + phys_addr_t *max, phys_addr_t *min) { - return PHYS_ADDR_MAX; + if (max) + *max =3D PHYS_ADDR_MAX; + if (min) + *min =3D 0; } =20 static inline const void *of_device_get_match_data(const struct device *de= v) --=20 2.43.0