[PATCH v2 1/5] drivers: of: add initialization code for reserved memory

[Marek Szyprowski]

This patch adds device tree support for contiguous and reserved memory
regions defined in device tree.

Large memory blocks can be reliably reserved only during early boot.
This must happen before the whole memory management subsystem is
initialized, because we need to ensure that the given contiguous blocks
are not yet allocated by kernel. Also it must happen before kernel
mappings for the whole low memory are created, to ensure that there will
be no mappings (for reserved blocks) or mapping with special properties
can be created (for CMA blocks). This all happens before device tree
structures are unflattened, so we need to get reserved memory layout
directly from fdt.

Later, those reserved memory regions are assigned to devices on each
device structure initialization.

Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Laura Abbott <lauraa@xxxxxxxxxxxxxx>
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
[joshc: rework to implement new DT binding, provide mechanism for
 plugging in new reserved-memory node handlers via
 RESERVEDMEM_OF_DECLARE]
Signed-off-by: Josh Cartwright <joshc@xxxxxxxxxxxxxx>
[mszyprow: little code cleanup]
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
 drivers/of/Kconfig                |    6 +
 drivers/of/Makefile               |    1 +
 drivers/of/of_reserved_mem.c      |  219 +++++++++++++++++++++++++++++++++++++
 drivers/of/platform.c             |    7 ++
 include/asm-generic/vmlinux.lds.h |   11 ++
 include/linux/of_reserved_mem.h   |   62 +++++++++++
 6 files changed, 306 insertions(+)
 create mode 100644 drivers/of/of_reserved_mem.c
 create mode 100644 include/linux/of_reserved_mem.h

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index c6973f101a3e..aba13df56f3a 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -75,4 +75,10 @@ config OF_MTD
 	depends on MTD
 	def_bool y
 
+config OF_RESERVED_MEM
+	depends on HAVE_MEMBLOCK
+	def_bool y
+	help
+	  Helpers to allow for reservation of memory regions
+
 endmenu # OF
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index efd05102c405..ed9660adad77 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_OF_MDIO)	+= of_mdio.o
 obj-$(CONFIG_OF_PCI)	+= of_pci.o
 obj-$(CONFIG_OF_PCI_IRQ)  += of_pci_irq.o
 obj-$(CONFIG_OF_MTD)	+= of_mtd.o
+obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
new file mode 100644
index 000000000000..f17cd56e68d9
--- /dev/null
+++ b/drivers/of/of_reserved_mem.c
@@ -0,0 +1,219 @@
+/*
+ * Device tree based initialization code for reserved memory.
+ *
+ * Copyright (c) 2013, The Linux Foundation. All Rights Reserved.
+ * Copyright (c) 2013 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ * Author: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
+ * Author: Josh Cartwright <joshc@xxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_platform.h>
+#include <linux/mm.h>
+#include <linux/sizes.h>
+#include <linux/of_reserved_mem.h>
+
+#define MAX_RESERVED_REGIONS	16
+static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
+static int reserved_mem_count;
+
+int __init of_parse_flat_dt_reg(unsigned long node, const char *uname,
+				   phys_addr_t *base, phys_addr_t *size)
+{
+	unsigned long len;
+	__be32 *prop;
+
+	prop = of_get_flat_dt_prop(node, "reg", &len);
+	if (!prop)
+		return -EINVAL;
+
+	if (len < (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32)) {
+		pr_err("Reserved memory: invalid reg property in '%s' node.\n",
+				uname);
+		return -EINVAL;
+	}
+
+	*base = dt_mem_next_cell(dt_root_addr_cells, &prop);
+	*size = dt_mem_next_cell(dt_root_size_cells, &prop);
+	return 0;
+}
+
+int __init of_parse_flat_dt_size(unsigned long node, const char *uname,
+				    phys_addr_t *size)
+{
+	unsigned long len;
+	__be32 *prop;
+
+	prop = of_get_flat_dt_prop(node, "size", &len);
+	if (!prop)
+		return -EINVAL;
+
+	if (len < dt_root_size_cells * sizeof(__be32)) {
+		pr_err("Reserved memory: invalid size property in '%s' node.\n",
+				uname);
+		return -EINVAL;
+	}
+
+	*size = dt_mem_next_cell(dt_root_size_cells, &prop);
+	return 0;
+}
+
+static int __init rmem_default_early_setup(struct reserved_mem *rmem,
+					   unsigned long node,
+					   const char *uname)
+{
+	int err;
+
+	if (of_get_flat_dt_prop(node, "compatible", NULL))
+		return -EINVAL;
+
+	err = of_parse_flat_dt_reg(node, uname, &rmem->base, &rmem->size);
+	if (err)
+		return err;
+
+	if (of_get_flat_dt_prop(node, "no-map", NULL))
+		err = memblock_remove(rmem->base, rmem->size);
+	else
+		err = memblock_reserve(rmem->base, rmem->size);
+
+	if (err == 0)
+		pr_info("Reserved memory: found '%s', memory base %pa, size %ld MiB\n",
+			uname, &rmem->base, (unsigned long)rmem->size / SZ_1M);
+
+	return err;
+}
+
+static const struct of_device_id rmem_default_id
+	__used __section(__reservedmem_of_table_end) = {
+	.data		= rmem_default_early_setup,
+};
+
+static int __init fdt_scan_reserved_mem(unsigned long node, const char *uname,
+					int depth, void *data)
+{
+	struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
+	extern const struct of_device_id __reservedmem_of_table[];
+	const struct of_device_id *id;
+	const char *status;
+
+	if (reserved_mem_count == ARRAY_SIZE(reserved_mem)) {
+		pr_err("Reserved memory: not enough space all defined regions.\n");
+		return -ENOSPC;
+	}
+
+	status = of_get_flat_dt_prop(node, "status", NULL);
+	if (status && strcmp(status, "okay") != 0)
+		return 0;
+
+	/*
+	 * The default handler above ensures this section is terminated with a
+	 * id whose compatible string is empty
+	 */
+	for (id = __reservedmem_of_table; id <= &rmem_default_id; id++) {
+		reservedmem_of_init_fn initfn = id->data;
+		const char *compat = id->compatible;
+
+		if (compat[0] && !of_flat_dt_is_compatible(node, compat))
+			continue;
+
+		if (initfn(rmem, node, uname) == 0) {
+			pr_info("Reserved memory: created %s node, compatible id %s\n",
+				uname, compat);
+			rmem->name = uname;
+			reserved_mem_count++;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static struct reserved_mem *find_rmem(struct device_node *np)
+{
+	const char *name;
+	unsigned int i;
+
+	name = kbasename(np->full_name);
+
+	for (i = 0; i < reserved_mem_count; i++)
+		if (strcmp(name, reserved_mem[i].name) == 0)
+			return &reserved_mem[i];
+
+	return NULL;
+}
+
+/**
+ * of_reserved_mem_device_init() - assign reserved memory region to given device
+ *
+ * This function assign memory region pointed by "memory-region" device tree
+ * property to the given device.
+ */
+void of_reserved_mem_device_init(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct reserved_mem *rmem;
+	struct of_phandle_args s;
+	unsigned int i;
+
+	for (i = 0; of_parse_phandle_with_args(np, "memory-region",
+				"#memory-region-cells", i, &s) == 0; i++) {
+
+		rmem = find_rmem(s.np);
+		if (!rmem || !rmem->ops || !rmem->ops->device_init) {
+			of_node_put(s.np);
+			continue;
+		}
+
+		rmem->ops->device_init(rmem, dev, &s);
+		dev_info(dev, "assigned reserved memory node %s\n",
+			 rmem->name);
+		of_node_put(s.np);
+		break;
+	}
+}
+
+/**
+ * of_reserved_mem_device_release() - release reserved memory device structures
+ *
+ * This function releases structures allocated for memory region handling for
+ * the given device.
+ */
+void of_reserved_mem_device_release(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct reserved_mem *rmem;
+	struct of_phandle_args s;
+	unsigned int i;
+
+	for (i = 0; of_parse_phandle_with_args(np, "memory-region",
+				"#memory-region-cells", i, &s) == 0; i++) {
+
+		rmem = find_rmem(s.np);
+		if (rmem && rmem->ops && rmem->ops->device_release)
+			rmem->ops->device_release(rmem, dev);
+
+		of_node_put(s.np);
+	}
+}
+
+/**
+ * early_init_dt_scan_reserved_mem() - create reserved memory regions
+ *
+ * This function grabs memory from early allocator for device exclusive use
+ * defined in device tree structures. It should be called by arch specific code
+ * once the early allocator (memblock) has been activated and all other
+ * subsystems have already allocated/reserved memory.
+ */
+void __init early_init_dt_scan_reserved_mem(void)
+{
+	of_scan_flat_dt_by_path("/reserved-memory", fdt_scan_reserved_mem,
+				NULL);
+}
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 404d1daebefa..3df0b1826e8b 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -21,6 +21,7 @@
 #include <linux/of_device.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/platform_device.h>
 
 const struct of_device_id of_default_bus_match_table[] = {
@@ -220,6 +221,8 @@ static struct platform_device *of_platform_device_create_pdata(
 	dev->dev.bus = &platform_bus_type;
 	dev->dev.platform_data = platform_data;
 
+	of_reserved_mem_device_init(&dev->dev);
+
 	/* We do not fill the DMA ops for platform devices by default.
 	 * This is currently the responsibility of the platform code
 	 * to do such, possibly using a device notifier
@@ -227,6 +230,7 @@ static struct platform_device *of_platform_device_create_pdata(
 
 	if (of_device_add(dev) != 0) {
 		platform_device_put(dev);
+		of_reserved_mem_device_release(&dev->dev);
 		return NULL;
 	}
 
@@ -282,6 +286,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
 	else
 		of_device_make_bus_id(&dev->dev);
 
+	of_reserved_mem_device_init(&dev->dev);
+
 	/* Allow the HW Peripheral ID to be overridden */
 	prop = of_get_property(node, "arm,primecell-periphid", NULL);
 	if (prop)
@@ -308,6 +314,7 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
 	return dev;
 
 err_free:
+	of_reserved_mem_device_release(&dev->dev);
 	amba_device_put(dev);
 	return NULL;
 }
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index bc2121fa9132..f10f64fcc815 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -167,6 +167,16 @@
 #define CLK_OF_TABLES()
 #endif
 
+#ifdef CONFIG_OF_RESERVED_MEM
+#define RESERVEDMEM_OF_TABLES()				\
+	. = ALIGN(8);					\
+	VMLINUX_SYMBOL(__reservedmem_of_table) = .;	\
+	*(__reservedmem_of_table)			\
+	*(__reservedmem_of_table_end)
+#else
+#define RESERVEDMEM_OF_TABLES()
+#endif
+
 #define KERNEL_DTB()							\
 	STRUCT_ALIGN();							\
 	VMLINUX_SYMBOL(__dtb_start) = .;				\
@@ -490,6 +500,7 @@
 	TRACE_SYSCALLS()						\
 	MEM_DISCARD(init.rodata)					\
 	CLK_OF_TABLES()							\
+	RESERVEDMEM_OF_TABLES()						\
 	CLKSRC_OF_TABLES()						\
 	KERNEL_DTB()							\
 	IRQCHIP_OF_MATCH_TABLE()
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
new file mode 100644
index 000000000000..41f43828e1db
--- /dev/null
+++ b/include/linux/of_reserved_mem.h
@@ -0,0 +1,62 @@
+#ifndef __OF_RESERVED_MEM_H
+#define __OF_RESERVED_MEM_H
+
+struct cma;
+struct platform_device;
+struct of_phandle_args;
+struct reserved_mem_ops;
+
+struct reserved_mem {
+	const char			*name;
+	const struct reserved_mem_ops	*ops;
+	phys_addr_t			base;
+	phys_addr_t			size;
+	void				*priv;
+};
+
+struct reserved_mem_ops {
+	void	(*device_init)(struct reserved_mem *rmem,
+			       struct device *dev,
+			       struct of_phandle_args *args);
+	void	(*device_release)(struct reserved_mem *rmem,
+				  struct device *dev);
+};
+
+typedef int (*reservedmem_of_init_fn)(struct reserved_mem *rmem,
+				      unsigned long node, const char *uname);
+
+#ifdef CONFIG_OF_RESERVED_MEM
+void of_reserved_mem_device_init(struct device *dev);
+void of_reserved_mem_device_release(struct device *dev);
+void early_init_dt_scan_reserved_mem(void);
+
+int of_parse_flat_dt_reg(unsigned long node, const char *uname,
+			 phys_addr_t *base, phys_addr_t *size);
+int of_parse_flat_dt_size(unsigned long node, const char *uname,
+			  phys_addr_t *size);
+
+#define RESERVEDMEM_OF_DECLARE(name, compat, init)			\
+	static const struct of_device_id __reservedmem_of_table_##name	\
+		__used __section(__reservedmem_of_table)		\
+		 = { .compatible = compat,				\
+		     .data = (init == (reservedmem_of_init_fn)NULL) ?	\
+				init : init }
+
+#else
+static inline void of_reserved_mem_device_init(struct device *dev) { }
+
+static inline
+void of_reserved_mem_device_release(struct device *dev) { }
+
+static inline void early_init_dt_scan_reserved_mem(void) { }
+
+#define RESERVEDMEM_OF_DECLARE(name, compat, init)			\
+	static const struct of_device_id __reservedmem_of_table_##name	\
+		__attribute__((unused))					\
+		 = { .compatible = compat,				\
+		     .data = (init == (reservedmem_of_init_fn)NULL) ?	\
+				init : init }
+
+#endif
+
+#endif /* __OF_RESERVED_MEM_H */
-- 
1.7.9.5

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