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/*
* 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/kernel.h>
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/genalloc.h>
#define SRAM_GRANULARITY 32
struct sram_dev {
struct gen_pool *pool;
struct clk *clk;
};
static int sram_probe(struct platform_device *pdev)
{
void __iomem *virt_base;
struct sram_dev *sram;
struct resource *res;
unsigned long size;
int ret;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
virt_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(virt_base))
return PTR_ERR(virt_base);
size = resource_size(res);
sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);
if (!sram)
return -ENOMEM;
sram->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(sram->clk))
sram->clk = NULL;
else
clk_prepare_enable(sram->clk);
sram->pool = devm_gen_pool_create(&pdev->dev, ilog2(SRAM_GRANULARITY), -1);
if (!sram->pool)
return -ENOMEM;
ret = gen_pool_add_virt(sram->pool, (unsigned long)virt_base,
res->start, size, -1);
if (ret < 0) {
gen_pool_destroy(sram->pool);
return ret;
}
platform_set_drvdata(pdev, sram);
dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base);
return 0;
}
static int sram_remove(struct platform_device *pdev)
{
struct sram_dev *sram = platform_get_drvdata(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);
return 0;
}
#ifdef CONFIG_OF
static 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);
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