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From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: robh+dt@kernel.org, catalin.marinas@arm.com, hch@lst.de,
	ardb@kernel.org, linux-kernel@vger.kernel.org,
	Frank Rowand <frowand.list@gmail.com>
Cc: devicetree@vger.kernel.org, jeremy.linton@arm.com,
	iommu@lists.linux-foundation.org,
	linux-rpi-kernel@lists.infradead.org, robin.murphy@arm.com,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 3/8] of/address: Introduce of_dma_get_max_cpu_address()
Date: Wed, 14 Oct 2020 21:12:05 +0200
Message-ID: <20201014191211.27029-4-nsaenzjulienne@suse.de> (raw)
In-Reply-To: <20201014191211.27029-1-nsaenzjulienne@suse.de>

Introduce of_dma_get_max_cpu_address(), which provides the highest CPU
physical address addressable by all DMA masters in the system. It's
specially useful for setting memory zones sizes at early boot time.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>

---

Changes since v2:
 - Use PHYS_ADDR_MAX
 - return phys_dma_t
 - Rename function
 - Correct subject
 - Add support to start parsing from an arbitrary device node in order
   for the function to work with unit tests

 drivers/of/address.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h   |  7 +++++++
 2 files changed, 49 insertions(+)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index eb9ab4f1e80b..b5a9695aaf82 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -1024,6 +1024,48 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
 }
 #endif /* CONFIG_HAS_DMA */
 
+/**
+ * of_dma_get_max_cpu_address - Gets highest CPU address suitable for DMA
+ * @np: The node to start searching from or NULL to start from the root
+ *
+ * Gets the highest CPU physical address that is addressable by all DMA masters
+ * in the system (or subtree when np is non-NULL). If no DMA constrained device
+ * is found, it returns PHYS_ADDR_MAX.
+ */
+phys_addr_t __init of_dma_get_max_cpu_address(struct device_node *np)
+{
+	phys_addr_t max_cpu_addr = PHYS_ADDR_MAX;
+	struct of_range_parser parser;
+	phys_addr_t subtree_max_addr;
+	struct device_node *child;
+	phys_addr_t cpu_end = 0;
+	struct of_range range;
+	const __be32 *ranges;
+	int len;
+
+	if (!np)
+		np = of_root;
+
+	ranges = 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)
+				cpu_end = range.cpu_addr + range.size;
+
+		if (max_cpu_addr > cpu_end)
+			max_cpu_addr = cpu_end;
+	}
+
+	for_each_available_child_of_node(np, child) {
+		subtree_max_addr = of_dma_get_max_cpu_address(child);
+		if (max_cpu_addr > subtree_max_addr)
+			max_cpu_addr = subtree_max_addr;
+	}
+
+	return max_cpu_addr;
+}
+
 /**
  * of_dma_is_coherent - Check if device is coherent
  * @np:	device node
diff --git a/include/linux/of.h b/include/linux/of.h
index 481ec0467285..db8db8f2c967 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -558,6 +558,8 @@ 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);
 
+phys_addr_t of_dma_get_max_cpu_address(struct device_node *np);
+
 #else /* CONFIG_OF */
 
 static inline void of_core_init(void)
@@ -995,6 +997,11 @@ static inline int of_map_id(struct device_node *np, u32 id,
 	return -EINVAL;
 }
 
+static inline phys_addr_t of_dma_get_max_cpu_address(struct device_node *np)
+{
+	return PHYS_ADDR_MAX;
+}
+
 #define of_match_ptr(_ptr)	NULL
 #define of_match_node(_matches, _node)	NULL
 #endif /* CONFIG_OF */
-- 
2.28.0

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  parent reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-14 19:12 [PATCH v3 0/8] arm64: Default to 32-bit wide ZONE_DMA Nicolas Saenz Julienne
2020-10-14 19:12 ` [PATCH v3 1/8] arm64: mm: Move reserve_crashkernel() into mem_init() Nicolas Saenz Julienne
2020-10-15  8:40   ` Will Deacon
2020-10-15  8:55     ` Nicolas Saenz Julienne
2020-10-14 19:12 ` [PATCH v3 2/8] arm64: mm: Move zone_dma_bits initialization into zone_sizes_init() Nicolas Saenz Julienne
2020-10-14 19:12 ` Nicolas Saenz Julienne [this message]
2020-10-14 22:02   ` [PATCH v3 3/8] of/address: Introduce of_dma_get_max_cpu_address() Rob Herring
2020-10-15  6:56     ` Ard Biesheuvel
2020-10-15  9:16       ` Nicolas Saenz Julienne
2020-10-15  9:18         ` Ard Biesheuvel
2020-10-15  8:54     ` Nicolas Saenz Julienne
2020-10-15  5:42   ` Christoph Hellwig
2020-10-15 10:03     ` Nicolas Saenz Julienne
2020-10-16 13:19     ` Rob Herring
2020-10-14 19:12 ` [PATCH v3 4/8] of: unittest: Add test for of_dma_get_max_cpu_address() Nicolas Saenz Julienne
2020-10-14 22:04   ` Rob Herring
2020-10-15  9:51     ` Nicolas Saenz Julienne
2020-10-14 19:12 ` [PATCH v3 5/8] dma-direct: Turn zone_dma_bits default value into a define Nicolas Saenz Julienne
2020-10-15  5:38   ` Christoph Hellwig
2020-10-15 10:05     ` Nicolas Saenz Julienne
2020-10-14 19:12 ` [PATCH v3 6/8] arm64: mm: Set ZONE_DMA size based on devicetree's dma-ranges Nicolas Saenz Julienne
2020-10-15  5:39   ` Christoph Hellwig
2020-10-15 10:05     ` Nicolas Saenz Julienne
2020-10-14 19:12 ` [PATCH v3 7/8] arm64: mm: Set ZONE_DMA size based on early IORT scan Nicolas Saenz Julienne
2020-10-15 10:31   ` Lorenzo Pieralisi
2020-10-16  6:56     ` Ard Biesheuvel
2020-10-15 14:26   ` Hanjun Guo
2020-10-15 15:15     ` Nicolas Saenz Julienne
2020-10-15 18:03     ` Catalin Marinas
2020-10-16  6:51       ` Hanjun Guo
2020-10-16  6:54         ` Ard Biesheuvel
2020-10-16  7:27           ` Hanjun Guo
2020-10-16  7:34             ` Hanjun Guo
2020-10-14 19:12 ` [PATCH v3 8/8] mm: Update DMA zones description Nicolas Saenz Julienne
2020-10-15  5:40   ` Christoph Hellwig

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