1 files changed, 118 insertions, 9 deletions

diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
index afe66571ce0b..21181fa243df 100644
--- a/drivers/misc/sram.c
+++ b/drivers/misc/sram.c
@@ -24,6 +24,9 @@
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/list.h>
+#include <linux/list_sort.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -36,14 +39,35 @@ struct sram_dev {
         struct clk *clk;
 };
 
+struct sram_reserve {
+        struct list_head list;
+        u32 start;
+        u32 size;
+};
+
+static int sram_reserve_cmp(void *priv, struct list_head *a,
+                                        struct list_head *b)
+{
+        struct sram_reserve *ra = list_entry(a, struct sram_reserve, list);
+        struct sram_reserve *rb = list_entry(b, struct sram_reserve, list);
+
+        return ra->start - rb->start;
+}
+
 static int sram_probe(struct platform_device *pdev)
 {
         void __iomem *virt_base;
         struct sram_dev *sram;
         struct resource *res;
-        unsigned long size;
+        struct device_node *np = pdev->dev.of_node, *child;
+        unsigned long size, cur_start, cur_size;
+        struct sram_reserve *rblocks, *block;
+        struct list_head reserve_list;
+        unsigned int nblocks;
         int ret;
 
+        INIT_LIST_HEAD(&reserve_list);
+
         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         virt_base = devm_ioremap_resource(&pdev->dev, res);
         if (IS_ERR(virt_base))
@@ -65,19 +89,106 @@ static int sram_probe(struct platform_device *pdev)
         if (!sram->pool)
                 return -ENOMEM;
 
-        ret = gen_pool_add_virt(sram->pool, (unsigned long)virt_base,
-                                res->start, size, -1);
-        if (ret < 0) {
-                if (sram->clk)
-                        clk_disable_unprepare(sram->clk);
-                return ret;
+        /*
+         * We need an additional block to mark the end of the memory region
+         * after the reserved blocks from the dt are processed.
+         */
+        nblocks = (np) ? of_get_available_child_count(np) + 1 : 1;
+        rblocks = kmalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
+        if (!rblocks) {
+                ret = -ENOMEM;
+                goto err_alloc;
+        }
+
+        block = &rblocks[0];
+        for_each_available_child_of_node(np, child) {
+                struct resource child_res;
+
+                ret = of_address_to_resource(child, 0, &child_res);
+                if (ret < 0) {
+                        dev_err(&pdev->dev,
+                                "could not get address for node %s\n",
+                                child->full_name);
+                        goto err_chunks;
+                }
+
+                if (child_res.start < res->start || child_res.end > res->end) {
+                        dev_err(&pdev->dev,
+                                "reserved block %s outside the sram area\n",
+                                child->full_name);
+                        ret = -EINVAL;
+                        goto err_chunks;
+                }
+
+                block->start = child_res.start - res->start;
+                block->size = resource_size(&child_res);
+                list_add_tail(&block->list, &reserve_list);
+
+                dev_dbg(&pdev->dev, "found reserved block 0x%x-0x%x\n",
+                        block->start,
+                        block->start + block->size);
+
+                block++;
+        }
+
+        /* the last chunk marks the end of the region */
+        rblocks[nblocks - 1].start = size;
+        rblocks[nblocks - 1].size = 0;
+        list_add_tail(&rblocks[nblocks - 1].list, &reserve_list);
+
+        list_sort(NULL, &reserve_list, sram_reserve_cmp);
+
+        cur_start = 0;
+
+        list_for_each_entry(block, &reserve_list, list) {
+                /* can only happen if sections overlap */
+                if (block->start < cur_start) {
+                        dev_err(&pdev->dev,
+                                "block at 0x%x starts after current offset 0x%lx\n",
+                                block->start, cur_start);
+                        ret = -EINVAL;
+                        goto err_chunks;
+                }
+
+                /* current start is in a reserved block, so continue after it */
+                if (block->start == cur_start) {
+                        cur_start = block->start + block->size;
+                        continue;
+                }
+
+                /*
+                 * allocate the space between the current starting
+                 * address and the following reserved block, or the
+                 * end of the region.
+                 */
+                cur_size = block->start - cur_start;
+
+                dev_dbg(&pdev->dev, "adding chunk 0x%lx-0x%lx\n",
+                        cur_start, cur_start + cur_size);
+                ret = gen_pool_add_virt(sram->pool,
+                                (unsigned long)virt_base + cur_start,
+                                res->start + cur_start, cur_size, -1);
+                if (ret < 0)
+                        goto err_chunks;
+
+                /* next allocation after this reserved block */
+                cur_start = block->start + block->size;
         }
 
+        kfree(rblocks);
+
         platform_set_drvdata(pdev, sram);
 
         dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base);
 
         return 0;
+
+err_chunks:
+        kfree(rblocks);
+err_alloc:
+        if (sram->clk)
+                clk_disable_unprepare(sram->clk);
+        return ret;
 }
 
 static int sram_remove(struct platform_device *pdev)
@@ -87,8 +198,6 @@ static int sram_remove(struct platform_device *pdev)
         if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool))
                 dev_dbg(&pdev->dev, "removed while SRAM allocated\n");
 
-        gen_pool_destroy(sram->pool);
-
         if (sram->clk)
                 clk_disable_unprepare(sram->clk);