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![Heiko Stübner](/assets/img/avatar_default.png)
This implements support for defining reserved areas as subnodes, to keep the genpool from using these. Suggested-by: Rob Herring <robherring2@gmail.com> Signed-off-by: Heiko Stuebner <heiko@sntech.de> Tested-by: Ulrich Prinz <ulrich.prinz@googlemail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
228 lines
5.6 KiB
C
228 lines
5.6 KiB
C
/*
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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/of_address.h>
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#include <linux/list.h>
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#include <linux/list_sort.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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struct sram_reserve {
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struct list_head list;
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u32 start;
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u32 size;
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};
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static int sram_reserve_cmp(void *priv, struct list_head *a,
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struct list_head *b)
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{
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struct sram_reserve *ra = list_entry(a, struct sram_reserve, list);
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struct sram_reserve *rb = list_entry(b, struct sram_reserve, list);
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return ra->start - rb->start;
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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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struct device_node *np = pdev->dev.of_node, *child;
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unsigned long size, cur_start, cur_size;
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struct sram_reserve *rblocks, *block;
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struct list_head reserve_list;
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unsigned int nblocks;
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int ret;
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INIT_LIST_HEAD(&reserve_list);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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virt_base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(virt_base))
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return PTR_ERR(virt_base);
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size = resource_size(res);
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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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/*
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* We need an additional block to mark the end of the memory region
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* after the reserved blocks from the dt are processed.
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*/
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nblocks = (np) ? of_get_available_child_count(np) + 1 : 1;
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rblocks = kmalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
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if (!rblocks) {
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ret = -ENOMEM;
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goto err_alloc;
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}
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block = &rblocks[0];
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for_each_available_child_of_node(np, child) {
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struct resource child_res;
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ret = of_address_to_resource(child, 0, &child_res);
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if (ret < 0) {
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dev_err(&pdev->dev,
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"could not get address for node %s\n",
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child->full_name);
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goto err_chunks;
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}
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if (child_res.start < res->start || child_res.end > res->end) {
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dev_err(&pdev->dev,
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"reserved block %s outside the sram area\n",
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child->full_name);
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ret = -EINVAL;
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goto err_chunks;
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}
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block->start = child_res.start - res->start;
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block->size = resource_size(&child_res);
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list_add_tail(&block->list, &reserve_list);
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dev_dbg(&pdev->dev, "found reserved block 0x%x-0x%x\n",
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block->start,
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block->start + block->size);
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block++;
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}
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/* the last chunk marks the end of the region */
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rblocks[nblocks - 1].start = size;
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rblocks[nblocks - 1].size = 0;
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list_add_tail(&rblocks[nblocks - 1].list, &reserve_list);
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list_sort(NULL, &reserve_list, sram_reserve_cmp);
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cur_start = 0;
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list_for_each_entry(block, &reserve_list, list) {
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/* can only happen if sections overlap */
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if (block->start < cur_start) {
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dev_err(&pdev->dev,
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"block at 0x%x starts after current offset 0x%lx\n",
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block->start, cur_start);
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ret = -EINVAL;
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goto err_chunks;
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}
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/* current start is in a reserved block, so continue after it */
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if (block->start == cur_start) {
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cur_start = block->start + block->size;
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continue;
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}
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/*
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* allocate the space between the current starting
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* address and the following reserved block, or the
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* end of the region.
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*/
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cur_size = block->start - cur_start;
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dev_dbg(&pdev->dev, "adding chunk 0x%lx-0x%lx\n",
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cur_start, cur_start + cur_size);
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ret = gen_pool_add_virt(sram->pool,
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(unsigned long)virt_base + cur_start,
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res->start + cur_start, cur_size, -1);
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if (ret < 0)
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goto err_chunks;
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/* next allocation after this reserved block */
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cur_start = block->start + block->size;
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}
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kfree(rblocks);
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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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err_chunks:
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kfree(rblocks);
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err_alloc:
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if (sram->clk)
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clk_disable_unprepare(sram->clk);
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return ret;
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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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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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