/* * 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 #include #include #include #include #include #include #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; } if (of_property_read_bool(pdev->dev.of_node, "no-memory-wc")) sram->virt_base = devm_ioremap(sram->dev, res->start, size); else sram->virt_base = devm_ioremap_wc(sram->dev, res->start, size); if (!sram->virt_base) return -ENOMEM; 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);