--- /dev/null
+/*
+ * 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/of_address.h>
+#include <linux/list.h>
+#include <linux/list_sort.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;
+};
+
+struct sram_reserve {
+ struct list_head list;
+ u32 start;
+ u32 size;
+};
+
+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_probe(struct platform_device *pdev)
+{
+ void __iomem *virt_base;
+ struct sram_dev *sram;
+ struct resource *res;
+ struct device_node *np = pdev->dev.of_node, *child;
+ unsigned long size, cur_start, cur_size;
+ struct sram_reserve *rblocks, *block;
+ struct list_head reserve_list;
+ unsigned int nblocks;
+ int ret;
+
+ INIT_LIST_HEAD(&reserve_list);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "found no memory resource\n");
+ return -EINVAL;
+ }
+
+ size = resource_size(res);
+
+ if (!devm_request_mem_region(&pdev->dev,
+ res->start, size, pdev->name)) {
+ dev_err(&pdev->dev, "could not request region for resource\n");
+ return -EBUSY;
+ }
+
+ virt_base = devm_ioremap_wc(&pdev->dev, res->start, size);
+ if (IS_ERR(virt_base))
+ return PTR_ERR(virt_base);
+
+ 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;
+
+ /*
+ * 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 = kmalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
+ if (!rblocks) {
+ ret = -ENOMEM;
+ goto err_alloc;
+ }
+
+ 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(&pdev->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(&pdev->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);
+
+ dev_dbg(&pdev->dev, "found reserved block 0x%x-0x%x\n",
+ block->start,
+ block->start + block->size);
+
+ block++;
+ }
+
+ /* 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);
+
+ cur_start = 0;
+
+ list_for_each_entry(block, &reserve_list, list) {
+ /* can only happen if sections overlap */
+ if (block->start < cur_start) {
+ dev_err(&pdev->dev,
+ "block at 0x%x starts after current offset 0x%lx\n",
+ block->start, cur_start);
+ ret = -EINVAL;
+ 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(&pdev->dev, "adding chunk 0x%lx-0x%lx\n",
+ cur_start, cur_start + cur_size);
+ ret = gen_pool_add_virt(sram->pool,
+ (unsigned long)virt_base + cur_start,
+ res->start + cur_start, cur_size, -1);
+ if (ret < 0)
+ goto err_chunks;
+
+ /* next allocation after this reserved block */
+ cur_start = block->start + block->size;
+ }
+
+ kfree(rblocks);
+
+ platform_set_drvdata(pdev, sram);
+
+ dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base);
+
+ return 0;
+
+err_chunks:
+ kfree(rblocks);
+err_alloc:
+ if (sram->clk)
+ clk_disable_unprepare(sram->clk);
+ return ret;
+}
+
+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");
+
+ 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);
Code Review / kvmfornfv.git / blobdiff