1 /* 2 * Generic on-chip SRAM allocation driver 3 * 4 * Copyright (C) 2012 Philipp Zabel, Pengutronix 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 2 9 * of the License, or (at your option) any later version. 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 18 * MA 02110-1301, USA. 19 */ 20 21 #include <linux/kernel.h> 22 #include <linux/init.h> 23 #include <linux/clk.h> 24 #include <linux/err.h> 25 #include <linux/io.h> 26 #include <linux/of.h> 27 #include <linux/platform_device.h> 28 #include <linux/slab.h> 29 #include <linux/spinlock.h> 30 #include <linux/genalloc.h> 31 32 #define SRAM_GRANULARITY 32 33 34 struct sram_dev { 35 struct gen_pool *pool; 36 struct clk *clk; 37 }; 38 39 static int sram_probe(struct platform_device *pdev) 40 { 41 void __iomem *virt_base; 42 struct sram_dev *sram; 43 struct resource *res; 44 unsigned long size; 45 int ret; 46 47 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 48 if (!res) 49 return -EINVAL; 50 51 size = resource_size(res); 52 53 virt_base = devm_request_and_ioremap(&pdev->dev, res); 54 if (!virt_base) 55 return -EADDRNOTAVAIL; 56 57 sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL); 58 if (!sram) 59 return -ENOMEM; 60 61 sram->clk = devm_clk_get(&pdev->dev, NULL); 62 if (IS_ERR(sram->clk)) 63 sram->clk = NULL; 64 else 65 clk_prepare_enable(sram->clk); 66 67 sram->pool = devm_gen_pool_create(&pdev->dev, ilog2(SRAM_GRANULARITY), -1); 68 if (!sram->pool) 69 return -ENOMEM; 70 71 ret = gen_pool_add_virt(sram->pool, (unsigned long)virt_base, 72 res->start, size, -1); 73 if (ret < 0) { 74 gen_pool_destroy(sram->pool); 75 return ret; 76 } 77 78 platform_set_drvdata(pdev, sram); 79 80 dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base); 81 82 return 0; 83 } 84 85 static int sram_remove(struct platform_device *pdev) 86 { 87 struct sram_dev *sram = platform_get_drvdata(pdev); 88 89 if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool)) 90 dev_dbg(&pdev->dev, "removed while SRAM allocated\n"); 91 92 gen_pool_destroy(sram->pool); 93 94 if (sram->clk) 95 clk_disable_unprepare(sram->clk); 96 97 return 0; 98 } 99 100 #ifdef CONFIG_OF 101 static struct of_device_id sram_dt_ids[] = { 102 { .compatible = "mmio-sram" }, 103 {} 104 }; 105 #endif 106 107 static struct platform_driver sram_driver = { 108 .driver = { 109 .name = "sram", 110 .of_match_table = of_match_ptr(sram_dt_ids), 111 }, 112 .probe = sram_probe, 113 .remove = sram_remove, 114 }; 115 116 static int __init sram_init(void) 117 { 118 return platform_driver_register(&sram_driver); 119 } 120 121 postcore_initcall(sram_init); 122