Merge branch 'for-v3.12' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping

Pull DMA mapping update from Marek Szyprowski:
 "This contains an addition of Device Tree support for reserved memory
  regions (Contiguous Memory Allocator is one of the drivers for it) and
  changes required by the KVM extensions for PowerPC architectue"

* 'for-v3.12' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  ARM: init: add support for reserved memory defined by device tree
  drivers: of: add initialization code for dma reserved memory
  drivers: of: add function to scan fdt nodes given by path
  drivers: dma-contiguous: clean source code and prepare for device tree

6 files changed, 306 insertions, 75 deletions

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 6c9cdaa9200d..99802d6f3c60 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -96,7 +96,7 @@ static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
 #endif
 
 /**
- * dma_contiguous_reserve() - reserve area for contiguous memory handling
+ * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
  * @limit: End address of the reserved memory (optional, 0 for any).
  *
  * This function reserves memory from early allocator. It should be
@@ -124,22 +124,29 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 #endif
         }
 
-        if (selected_size) {
+        if (selected_size && !dma_contiguous_default_area) {
                 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
                          (unsigned long)selected_size / SZ_1M);
 
-                dma_declare_contiguous(NULL, selected_size, 0, limit);
+                dma_contiguous_reserve_area(selected_size, 0, limit,
+                                            &dma_contiguous_default_area);
         }
 };
 
 static DEFINE_MUTEX(cma_mutex);
 
-static int __init cma_activate_area(unsigned long base_pfn, unsigned long count)
+static int __init cma_activate_area(struct cma *cma)
 {
-        unsigned long pfn = base_pfn;
-        unsigned i = count >> pageblock_order;
+        int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
+        unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
+        unsigned i = cma->count >> pageblock_order;
         struct zone *zone;
 
+        cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+
+        if (!cma->bitmap)
+                return -ENOMEM;
+
         WARN_ON_ONCE(!pfn_valid(pfn));
         zone = page_zone(pfn_to_page(pfn));
 
@@ -153,92 +160,53 @@ static int __init cma_activate_area(unsigned long base_pfn, unsigned long count)
                 }
                 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
         } while (--i);
-        return 0;
-}
-
-static struct cma * __init cma_create_area(unsigned long base_pfn,
-                                     unsigned long count)
-{
-        int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
-        struct cma *cma;
-        int ret = -ENOMEM;
-
-        pr_debug("%s(base %08lx, count %lx)\n", __func__, base_pfn, count);
-
-        cma = kmalloc(sizeof *cma, GFP_KERNEL);
-        if (!cma)
-                return ERR_PTR(-ENOMEM);
-
-        cma->base_pfn = base_pfn;
-        cma->count = count;
-        cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
 
-        if (!cma->bitmap)
-                goto no_mem;
-
-        ret = cma_activate_area(base_pfn, count);
-        if (ret)
-                goto error;
-
-        pr_debug("%s: returned %p\n", __func__, (void *)cma);
-        return cma;
-
-error:
-        kfree(cma->bitmap);
-no_mem:
-        kfree(cma);
-        return ERR_PTR(ret);
+        return 0;
 }
 
-static struct cma_reserved {
-        phys_addr_t start;
-        unsigned long size;
-        struct device *dev;
-} cma_reserved[MAX_CMA_AREAS] __initdata;
-static unsigned cma_reserved_count __initdata;
+static struct cma cma_areas[MAX_CMA_AREAS];
+static unsigned cma_area_count;
 
 static int __init cma_init_reserved_areas(void)
 {
-        struct cma_reserved *r = cma_reserved;
-        unsigned i = cma_reserved_count;
-
-        pr_debug("%s()\n", __func__);
+        int i;
 
-        for (; i; --i, ++r) {
-                struct cma *cma;
-                cma = cma_create_area(PFN_DOWN(r->start),
-                                      r->size >> PAGE_SHIFT);
-                if (!IS_ERR(cma))
-                        dev_set_cma_area(r->dev, cma);
+        for (i = 0; i < cma_area_count; i++) {
+                int ret = cma_activate_area(&cma_areas[i]);
+                if (ret)
+                        return ret;
         }
+
         return 0;
 }
 core_initcall(cma_init_reserved_areas);
 
 /**
- * dma_declare_contiguous() - reserve area for contiguous memory handling
- *                            for particular device
- * @dev:   Pointer to device structure.
- * @size:  Size of the reserved memory.
- * @base:  Start address of the reserved memory (optional, 0 for any).
+ * dma_contiguous_reserve_area() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
  * @limit: End address of the reserved memory (optional, 0 for any).
+ * @res_cma: Pointer to store the created cma region.
  *
- * This function reserves memory for specified device. It should be
- * called by board specific code when early allocator (memblock or bootmem)
- * is still activate.
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas for specific
+ * devices.
  */
-int __init dma_declare_contiguous(struct device *dev, phys_addr_t size,
-                                  phys_addr_t base, phys_addr_t limit)
+int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
+                                       phys_addr_t limit, struct cma **res_cma)
 {
-        struct cma_reserved *r = &cma_reserved[cma_reserved_count];
+        struct cma *cma = &cma_areas[cma_area_count];
         phys_addr_t alignment;
+        int ret = 0;
 
         pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
                  (unsigned long)size, (unsigned long)base,
                  (unsigned long)limit);
 
         /* Sanity checks */
-        if (cma_reserved_count == ARRAY_SIZE(cma_reserved)) {
+        if (cma_area_count == ARRAY_SIZE(cma_areas)) {
                 pr_err("Not enough slots for CMA reserved regions!\n");
                 return -ENOSPC;
         }
@@ -256,7 +224,7 @@ int __init dma_declare_contiguous(struct device *dev, phys_addr_t size,
         if (base) {
                 if (memblock_is_region_reserved(base, size) ||
                     memblock_reserve(base, size) < 0) {
-                        base = -EBUSY;
+                        ret = -EBUSY;
                         goto err;
                 }
         } else {
@@ -266,7 +234,7 @@ int __init dma_declare_contiguous(struct device *dev, phys_addr_t size,
                  */
                 phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
                 if (!addr) {
-                        base = -ENOMEM;
+                        ret = -ENOMEM;
                         goto err;
                 } else {
                         base = addr;
@@ -277,10 +245,11 @@ int __init dma_declare_contiguous(struct device *dev, phys_addr_t size,
          * Each reserved area must be initialised later, when more kernel
          * subsystems (like slab allocator) are available.
          */
-        r->start = base;
-        r->size = size;
-        r->dev = dev;
-        cma_reserved_count++;
+        cma->base_pfn = PFN_DOWN(base);
+        cma->count = size >> PAGE_SHIFT;
+        *res_cma = cma;
+        cma_area_count++;
+
         pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
                 (unsigned long)base);
 
@@ -289,7 +258,7 @@ int __init dma_declare_contiguous(struct device *dev, phys_addr_t size,
         return 0;
 err:
         pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-        return base;
+        return ret;
 }
 
 /**
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 78cc76053328..9d2009a9004d 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -74,4 +74,10 @@ config OF_MTD
         depends on MTD
         def_bool y
 
+config OF_RESERVED_MEM
+        depends on OF_FLATTREE && (DMA_CMA || (HAVE_GENERIC_DMA_COHERENT && HAVE_MEMBLOCK))
+        def_bool y
+        help
+          Initialization code for DMA reserved memory
+
 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 b10ba00cc3e6..4fb06f3e7b3c 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -545,6 +545,82 @@ int __init of_flat_dt_match(unsigned long node, const char *const *compat)
         return of_fdt_match(initial_boot_params, node, compat);
 }
 
+struct fdt_scan_status {
+        const char *name;
+        int namelen;
+        int depth;
+        int found;
+        int (*iterator)(unsigned long node, const char *uname, int depth, void *data);
+        void *data;
+};
+
+/**
+ * fdt_scan_node_by_path - iterator for of_scan_flat_dt_by_path function
+ */
+static int __init fdt_scan_node_by_path(unsigned long node, const char *uname,
+                                        int depth, void *data)
+{
+        struct fdt_scan_status *st = data;
+
+        /*
+         * if scan at the requested fdt node has been completed,
+         * return -ENXIO to abort further scanning
+         */
+        if (depth <= st->depth)
+                return -ENXIO;
+
+        /* requested fdt node has been found, so call iterator function */
+        if (st->found)
+                return st->iterator(node, uname, depth, st->data);
+
+        /* check if scanning automata is entering next level of fdt nodes */
+        if (depth == st->depth + 1 &&
+            strncmp(st->name, uname, st->namelen) == 0 &&
+            uname[st->namelen] == 0) {
+                st->depth += 1;
+                if (st->name[st->namelen] == 0) {
+                        st->found = 1;
+                } else {
+                        const char *next = st->name + st->namelen + 1;
+                        st->name = next;
+                        st->namelen = strcspn(next, "/");
+                }
+                return 0;
+        }
+
+        /* scan next fdt node */
+        return 0;
+}
+
+/**
+ * of_scan_flat_dt_by_path - scan flattened tree blob and call callback on each
+ *                           child of the given path.
+ * @path: path to start searching for children
+ * @it: callback function
+ * @data: context data pointer
+ *
+ * This function is used to scan the flattened device-tree starting from the
+ * node given by path. It is used to extract information (like reserved
+ * memory), which is required on ealy boot before we can unflatten the tree.
+ */
+int __init of_scan_flat_dt_by_path(const char *path,
+        int (*it)(unsigned long node, const char *name, int depth, void *data),
+        void *data)
+{
+        struct fdt_scan_status st = {path, 0, -1, 0, it, data};
+        int ret = 0;
+
+        if (initial_boot_params)
+                ret = of_scan_flat_dt(fdt_scan_node_by_path, &st);
+
+        if (!st.found)
+                return -ENOENT;
+        else if (ret == -ENXIO) /* scan has been completed */
+                return 0;
+        else
+                return ret;
+}
+
 #ifdef CONFIG_BLK_DEV_INITRD
 /**
  * early_init_dt_check_for_initrd - Decode initrd location from flat tree
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
new file mode 100644
index 000000000000..a754b84ba016
--- /dev/null
+++ b/drivers/of/of_reserved_mem.c
@@ -0,0 +1,175 @@
+/*
+ * Device tree based initialization code for reserved memory.
+ *
+ * Copyright (c) 2013 Samsung Electronics Co., Ltd.
+ *              http://www.samsung.com
+ * Author: Marek Szyprowski <m.szyprowski@samsung.com>
+ *
+ * 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 <asm/dma-contiguous.h>
+
+#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/mm_types.h>
+#include <linux/dma-contiguous.h>
+#include <linux/dma-mapping.h>
+#include <linux/of_reserved_mem.h>
+
+#define MAX_RESERVED_REGIONS    16
+struct reserved_mem {
+        phys_addr_t             base;
+        unsigned long           size;
+        struct cma              *cma;
+        char                    name[32];
+};
+static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
+static int reserved_mem_count;
+
+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];
+        phys_addr_t base, size;
+        int is_cma, is_reserved;
+        unsigned long len;
+        const char *status;
+        __be32 *prop;
+
+        is_cma = IS_ENABLED(CONFIG_DMA_CMA) &&
+               of_flat_dt_is_compatible(node, "linux,contiguous-memory-region");
+        is_reserved = of_flat_dt_is_compatible(node, "reserved-memory-region");
+
+        if (!is_reserved && !is_cma) {
+                /* ignore node and scan next one */
+                return 0;
+        }
+
+        status = of_get_flat_dt_prop(node, "status", &len);
+        if (status && strcmp(status, "okay") != 0) {
+                /* ignore disabled node nad scan next one */
+                return 0;
+        }
+
+        prop = of_get_flat_dt_prop(node, "reg", &len);
+        if (!prop || (len < (dt_root_size_cells + dt_root_addr_cells) *
+                             sizeof(__be32))) {
+                pr_err("Reserved mem: node %s, incorrect \"reg\" property\n",
+                       uname);
+                /* ignore node and scan next one */
+                return 0;
+        }
+        base = dt_mem_next_cell(dt_root_addr_cells, &prop);
+        size = dt_mem_next_cell(dt_root_size_cells, &prop);
+
+        if (!size) {
+                /* ignore node and scan next one */
+                return 0;
+        }
+
+        pr_info("Reserved mem: found %s, memory base %lx, size %ld MiB\n",
+                uname, (unsigned long)base, (unsigned long)size / SZ_1M);
+
+        if (reserved_mem_count == ARRAY_SIZE(reserved_mem))
+                return -ENOSPC;
+
+        rmem->base = base;
+        rmem->size = size;
+        strlcpy(rmem->name, uname, sizeof(rmem->name));
+
+        if (is_cma) {
+                struct cma *cma;
+                if (dma_contiguous_reserve_area(size, base, 0, &cma) == 0) {
+                        rmem->cma = cma;
+                        reserved_mem_count++;
+                        if (of_get_flat_dt_prop(node,
+                                                "linux,default-contiguous-region",
+                                                NULL))
+                                dma_contiguous_set_default(cma);
+                }
+        } else if (is_reserved) {
+                if (memblock_remove(base, size) == 0)
+                        reserved_mem_count++;
+                else
+                        pr_err("Failed to reserve memory for %s\n", uname);
+        }
+
+        return 0;
+}
+
+static struct reserved_mem *get_dma_memory_region(struct device *dev)
+{
+        struct device_node *node;
+        const char *name;
+        int i;
+
+        node = of_parse_phandle(dev->of_node, "memory-region", 0);
+        if (!node)
+                return NULL;
+
+        name = kbasename(node->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 reserved_mem *region = get_dma_memory_region(dev);
+        if (!region)
+                return;
+
+        if (region->cma) {
+                dev_set_cma_area(dev, region->cma);
+                pr_info("Assigned CMA %s to %s device\n", region->name,
+                        dev_name(dev));
+        } else {
+                if (dma_declare_coherent_memory(dev, region->base, region->base,
+                    region->size, DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE) != 0)
+                        pr_info("Declared reserved memory %s to %s device\n",
+                                region->name, dev_name(dev));
+        }
+}
+
+/**
+ * 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 reserved_mem *region = get_dma_memory_region(dev);
+        if (!region && !region->cma)
+                dma_release_declared_memory(dev);
+}
+
+/**
+ * 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("/memory/reserved-memory",
+                                fdt_scan_reserved_mem, NULL);
+}
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index e0a6514ab46c..eeca8a596973 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[] = {
@@ -218,6 +219,8 @@ 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
@@ -225,6 +228,7 @@ 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;
         }