drivers: of: add initialization code for dynamic reserved memory

This patch adds support for dynamically allocated reserved memory regions
declared in device tree. Such regions are defined by 'size', 'alignment'
and 'alloc-ranges' properties.

Based on previous code provided by Josh Cartwright <joshc@codeaurora.org>

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>

4 files changed, 206 insertions, 2 deletions

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index ffdcb11f75fb..c144b8f990ff 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -79,4 +79,10 @@ config OF_MTD
         depends on MTD
         def_bool y
 
+config OF_RESERVED_MEM
+        depends on OF_EARLY_FLATTREE
+        bool
+        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/fdt.c b/drivers/of/fdt.c
index 819e11209718..510c0d8de8a0 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/sizes.h>
 #include <linux/string.h>
 #include <linux/errno.h>
@@ -450,7 +451,7 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
         phys_addr_t base, size;
         unsigned long len;
         __be32 *prop;
-        int nomap;
+        int nomap, first = 1;
 
         prop = of_get_flat_dt_prop(node, "reg", &len);
         if (!prop)
@@ -477,6 +478,10 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
                                 uname, &base, (unsigned long)size / SZ_1M);
 
                 len -= t_len;
+                if (first) {
+                        fdt_reserved_mem_save_node(node, uname, base, size);
+                        first = 0;
+                }
         }
         return 0;
 }
@@ -512,6 +517,7 @@ static int __init __fdt_scan_reserved_mem(unsigned long node, const char *uname,
 {
         static int found;
         const char *status;
+        int err;
 
         if (!found && depth == 1 && strcmp(uname, "reserved-memory") == 0) {
                 if (__reserved_mem_check_root(node) != 0) {
@@ -534,7 +540,9 @@ static int __init __fdt_scan_reserved_mem(unsigned long node, const char *uname,
         if (status && strcmp(status, "okay") != 0 && strcmp(status, "ok") != 0)
                 return 0;
 
-        __reserved_mem_reserve_reg(node, uname);
+        err = __reserved_mem_reserve_reg(node, uname);
+        if (err == -ENOENT && of_get_flat_dt_prop(node, "size", NULL))
+                fdt_reserved_mem_save_node(node, uname, 0, 0);
 
         /* scan next node */
         return 0;
@@ -550,6 +558,7 @@ static int __init __fdt_scan_reserved_mem(unsigned long node, const char *uname,
 void __init early_init_fdt_scan_reserved_mem(void)
 {
         of_scan_flat_dt(__fdt_scan_reserved_mem, NULL);
+        fdt_init_reserved_mem();
 }
 
 /**
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
new file mode 100644
index 000000000000..69b811779585
--- /dev/null
+++ b/drivers/of/of_reserved_mem.c
@@ -0,0 +1,188 @@
+/*
+ * Device tree based initialization code for reserved memory.
+ *
+ * Copyright (c) 2013, The Linux Foundation. All Rights Reserved.
+ * Copyright (c) 2013,2014 Samsung Electronics Co., Ltd.
+ *              http://www.samsung.com
+ * Author: Marek Szyprowski <m.szyprowski@samsung.com>
+ * Author: Josh Cartwright <joshc@codeaurora.org>
+ *
+ * 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/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;
+
+#if defined(CONFIG_HAVE_MEMBLOCK)
+#include <linux/memblock.h>
+int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
+        phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
+        phys_addr_t *res_base)
+{
+        /*
+         * We use __memblock_alloc_base() because memblock_alloc_base()
+         * panic()s on allocation failure.
+         */
+        phys_addr_t base = __memblock_alloc_base(size, align, end);
+        if (!base)
+                return -ENOMEM;
+
+        /*
+         * Check if the allocated region fits in to start..end window
+         */
+        if (base < start) {
+                memblock_free(base, size);
+                return -ENOMEM;
+        }
+
+        *res_base = base;
+        if (nomap)
+                return memblock_remove(base, size);
+        return 0;
+}
+#else
+int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
+        phys_addr_t align, phys_addr_t start, phys_addr_t end, bool nomap,
+        phys_addr_t *res_base)
+{
+        pr_err("Reserved memory not supported, ignoring region 0x%llx%s\n",
+                  size, nomap ? " (nomap)" : "");
+        return -ENOSYS;
+}
+#endif
+
+/**
+ * res_mem_save_node() - save fdt node for second pass initialization
+ */
+void __init fdt_reserved_mem_save_node(unsigned long node, const char *uname,
+                                      phys_addr_t base, phys_addr_t size)
+{
+        struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
+
+        if (reserved_mem_count == ARRAY_SIZE(reserved_mem)) {
+                pr_err("Reserved memory: not enough space all defined regions.\n");
+                return;
+        }
+
+        rmem->fdt_node = node;
+        rmem->name = uname;
+        rmem->base = base;
+        rmem->size = size;
+
+        reserved_mem_count++;
+        return;
+}
+
+/**
+ * res_mem_alloc_size() - allocate reserved memory described by 'size', 'align'
+ *                        and 'alloc-ranges' properties
+ */
+static int __init __reserved_mem_alloc_size(unsigned long node,
+        const char *uname, phys_addr_t *res_base, phys_addr_t *res_size)
+{
+        int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
+        phys_addr_t start = 0, end = 0;
+        phys_addr_t base = 0, align = 0, size;
+        unsigned long len;
+        __be32 *prop;
+        int nomap;
+        int ret;
+
+        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);
+
+        nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
+
+        prop = of_get_flat_dt_prop(node, "alignment", &len);
+        if (prop) {
+                if (len != dt_root_addr_cells * sizeof(__be32)) {
+                        pr_err("Reserved memory: invalid alignment property in '%s' node.\n",
+                                uname);
+                        return -EINVAL;
+                }
+                align = dt_mem_next_cell(dt_root_addr_cells, &prop);
+        }
+
+        prop = of_get_flat_dt_prop(node, "alloc-ranges", &len);
+        if (prop) {
+
+                if (len % t_len != 0) {
+                        pr_err("Reserved memory: invalid alloc-ranges property in '%s', skipping node.\n",
+                               uname);
+                        return -EINVAL;
+                }
+
+                base = 0;
+
+                while (len > 0) {
+                        start = dt_mem_next_cell(dt_root_addr_cells, &prop);
+                        end = start + dt_mem_next_cell(dt_root_size_cells,
+                                                       &prop);
+
+                        ret = early_init_dt_alloc_reserved_memory_arch(size,
+                                        align, start, end, nomap, &base);
+                        if (ret == 0) {
+                                pr_debug("Reserved memory: allocated memory for '%s' node: base %pa, size %ld MiB\n",
+                                        uname, &base,
+                                        (unsigned long)size / SZ_1M);
+                                break;
+                        }
+                        len -= t_len;
+                }
+
+        } else {
+                ret = early_init_dt_alloc_reserved_memory_arch(size, align,
+                                                        0, 0, nomap, &base);
+                if (ret == 0)
+                        pr_debug("Reserved memory: allocated memory for '%s' node: base %pa, size %ld MiB\n",
+                                uname, &base, (unsigned long)size / SZ_1M);
+        }
+
+        if (base == 0) {
+                pr_info("Reserved memory: failed to allocate memory for node '%s'\n",
+                        uname);
+                return -ENOMEM;
+        }
+
+        *res_base = base;
+        *res_size = size;
+
+        return 0;
+}
+
+/**
+ * fdt_init_reserved_mem - allocate and init all saved reserved memory regions
+ */
+void __init fdt_init_reserved_mem(void)
+{
+        int i;
+        for (i = 0; i < reserved_mem_count; i++) {
+                struct reserved_mem *rmem = &reserved_mem[i];
+                unsigned long node = rmem->fdt_node;
+                int err = 0;
+
+                if (rmem->size == 0)
+                        err = __reserved_mem_alloc_size(node, rmem->name,
+                                                 &rmem->base, &rmem->size);
+        }
+}