122 lines
2.8 KiB
C
122 lines
2.8 KiB
C
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/*
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* Generic on-chip SRAM allocation driver
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*
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* Copyright (C) 2012 Philipp Zabel, Pengutronix
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/genalloc.h>
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#define SRAM_GRANULARITY 32
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struct sram_dev {
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struct gen_pool *pool;
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struct clk *clk;
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};
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static int sram_probe(struct platform_device *pdev)
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{
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void __iomem *virt_base;
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struct sram_dev *sram;
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struct resource *res;
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unsigned long size;
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int ret;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res)
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return -EINVAL;
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size = resource_size(res);
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virt_base = devm_request_and_ioremap(&pdev->dev, res);
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if (!virt_base)
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return -EADDRNOTAVAIL;
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sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);
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if (!sram)
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return -ENOMEM;
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sram->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(sram->clk))
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sram->clk = NULL;
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else
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clk_prepare_enable(sram->clk);
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sram->pool = devm_gen_pool_create(&pdev->dev, ilog2(SRAM_GRANULARITY), -1);
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if (!sram->pool)
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return -ENOMEM;
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ret = gen_pool_add_virt(sram->pool, (unsigned long)virt_base,
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res->start, size, -1);
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if (ret < 0) {
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gen_pool_destroy(sram->pool);
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return ret;
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}
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platform_set_drvdata(pdev, sram);
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dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base);
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return 0;
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}
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static int sram_remove(struct platform_device *pdev)
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{
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struct sram_dev *sram = platform_get_drvdata(pdev);
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if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool))
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dev_dbg(&pdev->dev, "removed while SRAM allocated\n");
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gen_pool_destroy(sram->pool);
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if (sram->clk)
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clk_disable_unprepare(sram->clk);
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return 0;
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}
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#ifdef CONFIG_OF
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static struct of_device_id sram_dt_ids[] = {
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{ .compatible = "mmio-sram" },
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{}
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};
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#endif
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static struct platform_driver sram_driver = {
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.driver = {
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.name = "sram",
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.of_match_table = of_match_ptr(sram_dt_ids),
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},
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.probe = sram_probe,
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.remove = sram_remove,
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};
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static int __init sram_init(void)
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{
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return platform_driver_register(&sram_driver);
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}
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postcore_initcall(sram_init);
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