drivers: dma-contiguous: clean source code and prepare for device tree

This patch cleans the initialization of dma contiguous framework. The
all-in-one dma_declare_contiguous() function is now separated into
dma_contiguous_reserve_area() which only steals the the memory from
memblock allocator and dma_contiguous_add_device() function, which
assigns given device to the specified reserved memory area. This improves
the flexibility in defining contiguous memory areas and assigning device
to them, because now it is possible to assign more than one device to
the given contiguous memory area. Such split in initialization procedure
is also required for upcoming device tree support.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Tomasz Figa <t.figa@samsung.com>

1 files changed, 44 insertions, 75 deletions

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 0ca54421ce97..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 __init int 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 __init int cma_activate_area(unsigned long base_pfn, unsigned long count)
                 }
                 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
         } while (--i);
-        return 0;
-}
-
-static __init struct cma *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;
 }
 
 /**