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-rw-r--r--Documentation/devicetree/bindings/misc/sram.txt16
-rw-r--r--drivers/misc/sram.c196
2 files changed, 204 insertions, 8 deletions
diff --git a/Documentation/devicetree/bindings/misc/sram.txt b/Documentation/devicetree/bindings/misc/sram.txt
index 36cbe5aea990..42ee9438b771 100644
--- a/Documentation/devicetree/bindings/misc/sram.txt
+++ b/Documentation/devicetree/bindings/misc/sram.txt
@@ -33,6 +33,12 @@ Optional properties in the area nodes:
- compatible : standard definition, should contain a vendor specific string
in the form <vendor>,[<device>-]<usage>
+- pool : indicates that the particular reserved SRAM area is addressable
+ and in use by another device or devices
+- export : indicates that the reserved SRAM area may be accessed outside
+ of the kernel, e.g. by bootloader or userspace
+- label : the name for the reserved partition, if omitted, the label
+ is taken from the node name excluding the unit address.
Example:
@@ -48,4 +54,14 @@ sram: sram@5c000000 {
compatible = "socvendor,smp-sram";
reg = <0x100 0x50>;
};
+
+ device-sram@1000 {
+ reg = <0x1000 0x1000>;
+ pool;
+ };
+
+ exported@20000 {
+ reg = <0x20000 0x20000>;
+ export;
+ };
};
diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
index 431e1dd528bc..b0b5e9430bfe 100644
--- a/drivers/misc/sram.c
+++ b/drivers/misc/sram.c
@@ -28,20 +28,144 @@
#define SRAM_GRANULARITY 32
+struct sram_partition {
+ void *base;
+
+ struct gen_pool *pool;
+ struct bin_attribute battr;
+ struct mutex lock;
+};
+
struct sram_dev {
struct device *dev;
void __iomem *virt_base;
struct gen_pool *pool;
struct clk *clk;
+
+ struct sram_partition *partition;
+ u32 partitions;
};
struct sram_reserve {
struct list_head list;
u32 start;
u32 size;
+ bool export;
+ bool pool;
+ const char *label;
};
+static ssize_t sram_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t pos, size_t count)
+{
+ struct sram_partition *part;
+
+ part = container_of(attr, struct sram_partition, battr);
+
+ mutex_lock(&part->lock);
+ memcpy(buf, part->base + pos, count);
+ mutex_unlock(&part->lock);
+
+ return count;
+}
+
+static ssize_t sram_write(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t pos, size_t count)
+{
+ struct sram_partition *part;
+
+ part = container_of(attr, struct sram_partition, battr);
+
+ mutex_lock(&part->lock);
+ memcpy(part->base + pos, buf, count);
+ mutex_unlock(&part->lock);
+
+ return count;
+}
+
+static int sram_add_pool(struct sram_dev *sram, struct sram_reserve *block,
+ phys_addr_t start, struct sram_partition *part)
+{
+ int ret;
+
+ part->pool = devm_gen_pool_create(sram->dev, ilog2(SRAM_GRANULARITY),
+ NUMA_NO_NODE, block->label);
+ if (IS_ERR(part->pool))
+ return PTR_ERR(part->pool);
+
+ ret = gen_pool_add_virt(part->pool, (unsigned long)part->base, start,
+ block->size, NUMA_NO_NODE);
+ if (ret < 0) {
+ dev_err(sram->dev, "failed to register subpool: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int sram_add_export(struct sram_dev *sram, struct sram_reserve *block,
+ phys_addr_t start, struct sram_partition *part)
+{
+ sysfs_bin_attr_init(&part->battr);
+ part->battr.attr.name = devm_kasprintf(sram->dev, GFP_KERNEL,
+ "%llx.sram",
+ (unsigned long long)start);
+ if (!part->battr.attr.name)
+ return -ENOMEM;
+
+ part->battr.attr.mode = S_IRUSR | S_IWUSR;
+ part->battr.read = sram_read;
+ part->battr.write = sram_write;
+ part->battr.size = block->size;
+
+ return device_create_bin_file(sram->dev, &part->battr);
+}
+
+static int sram_add_partition(struct sram_dev *sram, struct sram_reserve *block,
+ phys_addr_t start)
+{
+ int ret;
+ struct sram_partition *part = &sram->partition[sram->partitions];
+
+ mutex_init(&part->lock);
+ part->base = sram->virt_base + block->start;
+
+ if (block->pool) {
+ ret = sram_add_pool(sram, block, start, part);
+ if (ret)
+ return ret;
+ }
+ if (block->export) {
+ ret = sram_add_export(sram, block, start, part);
+ if (ret)
+ return ret;
+ }
+ sram->partitions++;
+
+ return 0;
+}
+
+static void sram_free_partitions(struct sram_dev *sram)
+{
+ struct sram_partition *part;
+
+ if (!sram->partitions)
+ return;
+
+ part = &sram->partition[sram->partitions - 1];
+ for (; sram->partitions; sram->partitions--, part--) {
+ if (part->battr.size)
+ device_remove_bin_file(sram->dev, &part->battr);
+
+ if (part->pool &&
+ gen_pool_avail(part->pool) < gen_pool_size(part->pool))
+ dev_err(sram->dev, "removed pool while SRAM allocated\n");
+ }
+}
+
static int sram_reserve_cmp(void *priv, struct list_head *a,
struct list_head *b)
{
@@ -57,7 +181,8 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
unsigned long size, cur_start, cur_size;
struct sram_reserve *rblocks, *block;
struct list_head reserve_list;
- unsigned int nblocks;
+ unsigned int nblocks, exports = 0;
+ const char *label;
int ret = 0;
INIT_LIST_HEAD(&reserve_list);
@@ -69,7 +194,7 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
* 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);
+ rblocks = kzalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
if (!rblocks)
return -ENOMEM;
@@ -82,7 +207,6 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
dev_err(sram->dev,
"could not get address for node %s\n",
child->full_name);
- of_node_put(child);
goto err_chunks;
}
@@ -91,7 +215,6 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
"reserved block %s outside the sram area\n",
child->full_name);
ret = -EINVAL;
- of_node_put(child);
goto err_chunks;
}
@@ -99,11 +222,42 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
block->size = resource_size(&child_res);
list_add_tail(&block->list, &reserve_list);
- dev_dbg(sram->dev, "found reserved block 0x%x-0x%x\n",
- block->start, block->start + block->size);
+ if (of_find_property(child, "export", NULL))
+ block->export = true;
+
+ if (of_find_property(child, "pool", NULL))
+ block->pool = true;
+
+ if ((block->export || block->pool) && block->size) {
+ exports++;
+
+ label = NULL;
+ ret = of_property_read_string(child, "label", &label);
+ if (ret && ret != -EINVAL) {
+ dev_err(sram->dev,
+ "%s has invalid label name\n",
+ child->full_name);
+ goto err_chunks;
+ }
+ if (!label)
+ label = child->name;
+
+ block->label = devm_kstrdup(sram->dev,
+ label, GFP_KERNEL);
+ if (!block->label)
+ goto err_chunks;
+
+ dev_dbg(sram->dev, "found %sblock '%s' 0x%x-0x%x\n",
+ block->export ? "exported " : "", block->label,
+ block->start, block->start + block->size);
+ } else {
+ dev_dbg(sram->dev, "found reserved block 0x%x-0x%x\n",
+ block->start, block->start + block->size);
+ }
block++;
}
+ child = NULL;
/* the last chunk marks the end of the region */
rblocks[nblocks - 1].start = size;
@@ -112,8 +266,17 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
list_sort(NULL, &reserve_list, sram_reserve_cmp);
- cur_start = 0;
+ if (exports) {
+ sram->partition = devm_kzalloc(sram->dev,
+ exports * sizeof(*sram->partition),
+ GFP_KERNEL);
+ if (!sram->partition) {
+ ret = -ENOMEM;
+ goto err_chunks;
+ }
+ }
+ cur_start = 0;
list_for_each_entry(block, &reserve_list, list) {
/* can only happen if sections overlap */
if (block->start < cur_start) {
@@ -121,9 +284,19 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
"block at 0x%x starts after current offset 0x%lx\n",
block->start, cur_start);
ret = -EINVAL;
+ sram_free_partitions(sram);
goto err_chunks;
}
+ if ((block->export || block->pool) && block->size) {
+ ret = sram_add_partition(sram, block,
+ res->start + block->start);
+ if (ret) {
+ sram_free_partitions(sram);
+ 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;
@@ -143,14 +316,19 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
ret = gen_pool_add_virt(sram->pool,
(unsigned long)sram->virt_base + cur_start,
res->start + cur_start, cur_size, -1);
- if (ret < 0)
+ if (ret < 0) {
+ sram_free_partitions(sram);
goto err_chunks;
+ }
/* next allocation after this reserved block */
cur_start = block->start + block->size;
}
err_chunks:
+ if (child)
+ of_node_put(child);
+
kfree(rblocks);
return ret;
@@ -213,6 +391,8 @@ static int sram_remove(struct platform_device *pdev)
{
struct sram_dev *sram = platform_get_drvdata(pdev);
+ sram_free_partitions(sram);
+
if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool))
dev_err(sram->dev, "removed while SRAM allocated\n");