WSL2-Linux-Kernel/drivers/misc/sram.c

427 строки
10 KiB
C

/*
* 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);