File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
new file mode 100644
index 0000000..736dae7
--- /dev/null
+++ b/drivers/misc/sram.c
@@ -0,0 +1,426 @@
+/*
+ * Generic on-chip SRAM allocation driver
+ *
+ * Copyright (C) 2012 Philipp Zabel, Pengutronix
+ *
+ * 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 option) any later version.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include <linux/clk.h>
+#include <linux/genalloc.h>
+#include <linux/io.h>
+#include <linux/list_sort.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define SRAM_GRANULARITY 32
+
+struct sram_partition {
+ void __iomem *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_fromio(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_toio(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)
+{
+ 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_reserve_regions(struct sram_dev *sram, struct resource *res)
+{
+ struct device_node *np = sram->dev->of_node, *child;
+ unsigned long size, cur_start, cur_size;
+ struct sram_reserve *rblocks, *block;
+ struct list_head reserve_list;
+ unsigned int nblocks, exports = 0;
+ const char *label;
+ int ret = 0;
+
+ INIT_LIST_HEAD(&reserve_list);
+
+ size = resource_size(res);
+
+ /*
+ * 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 = kzalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
+ if (!rblocks)
+ return -ENOMEM;
+
+ 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(sram->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(sram->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);
+
+ 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;
+ rblocks[nblocks - 1].size = 0;
+ list_add_tail(&rblocks[nblocks - 1].list, &reserve_list);
+
+ list_sort(NULL, &reserve_list, sram_reserve_cmp);
+
+ 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) {
+ dev_err(sram->dev,
+ "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;
+ 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(sram->dev, "adding chunk 0x%lx-0x%lx\n",
+ cur_start, cur_start + cur_size);
+
+ ret = gen_pool_add_virt(sram->pool,
+ (unsigned long)sram->virt_base + cur_start,
+ res->start + cur_start, cur_size, -1);
+ 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;
+}
+
+static int sram_probe(struct platform_device *pdev)
+{
+ struct sram_dev *sram;
+ struct resource *res;
+ size_t size;
+ int ret;
+
+ sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);
+ if (!sram)
+ return -ENOMEM;
+
+ sram->dev = &pdev->dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(sram->dev, "found no memory resource\n");
+ return -EINVAL;
+ }
+
+ size = resource_size(res);
+
+ if (!devm_request_mem_region(sram->dev, res->start, size, pdev->name)) {
+ dev_err(sram->dev, "could not request region for resource\n");
+ return -EBUSY;
+ }
+
+ sram->virt_base = devm_ioremap_wc(sram->dev, res->start, size);
+ if (IS_ERR(sram->virt_base))
+ return PTR_ERR(sram->virt_base);
+
+ sram->pool = devm_gen_pool_create(sram->dev, ilog2(SRAM_GRANULARITY),
+ NUMA_NO_NODE, NULL);
+ if (IS_ERR(sram->pool))
+ return PTR_ERR(sram->pool);
+
+ ret = sram_reserve_regions(sram, res);
+ if (ret)
+ return ret;
+
+ sram->clk = devm_clk_get(sram->dev, NULL);
+ if (IS_ERR(sram->clk))
+ sram->clk = NULL;
+ else
+ clk_prepare_enable(sram->clk);
+
+ platform_set_drvdata(pdev, sram);
+
+ dev_dbg(sram->dev, "SRAM pool: %zu KiB @ 0x%p\n",
+ gen_pool_size(sram->pool) / 1024, sram->virt_base);
+
+ return 0;
+}
+
+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");
+
+ if (sram->clk)
+ clk_disable_unprepare(sram->clk);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id sram_dt_ids[] = {
+ { .compatible = "mmio-sram" },
+ {}
+};
+#endif
+
+static struct platform_driver sram_driver = {
+ .driver = {
+ .name = "sram",
+ .of_match_table = of_match_ptr(sram_dt_ids),
+ },
+ .probe = sram_probe,
+ .remove = sram_remove,
+};
+
+static int __init sram_init(void)
+{
+ return platform_driver_register(&sram_driver);
+}
+
+postcore_initcall(sram_init);