1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* drivers/mtd/maps/plat-ram.c 3 * 4 * (c) 2004-2005 Simtec Electronics 5 * http://www.simtec.co.uk/products/SWLINUX/ 6 * Ben Dooks <ben@simtec.co.uk> 7 * 8 * Generic platform device based RAM map 9 */ 10 11 #include <linux/module.h> 12 #include <linux/types.h> 13 #include <linux/kernel.h> 14 #include <linux/string.h> 15 #include <linux/ioport.h> 16 #include <linux/device.h> 17 #include <linux/slab.h> 18 #include <linux/platform_device.h> 19 20 #include <linux/mtd/mtd.h> 21 #include <linux/mtd/map.h> 22 #include <linux/mtd/partitions.h> 23 #include <linux/mtd/plat-ram.h> 24 25 #include <asm/io.h> 26 27 /* private structure for each mtd platform ram device created */ 28 29 struct platram_info { 30 struct device *dev; 31 struct mtd_info *mtd; 32 struct map_info map; 33 struct platdata_mtd_ram *pdata; 34 }; 35 36 /* to_platram_info() 37 * 38 * device private data to struct platram_info conversion 39 */ 40 41 static inline struct platram_info *to_platram_info(struct platform_device *dev) 42 { 43 return platform_get_drvdata(dev); 44 } 45 46 /* platram_setrw 47 * 48 * call the platform device's set rw/ro control 49 * 50 * to = 0 => read-only 51 * = 1 => read-write 52 */ 53 54 static inline void platram_setrw(struct platram_info *info, int to) 55 { 56 if (info->pdata == NULL) 57 return; 58 59 if (info->pdata->set_rw != NULL) 60 (info->pdata->set_rw)(info->dev, to); 61 } 62 63 /* platram_remove 64 * 65 * called to remove the device from the driver's control 66 */ 67 68 static void platram_remove(struct platform_device *pdev) 69 { 70 struct platram_info *info = to_platram_info(pdev); 71 72 dev_dbg(&pdev->dev, "removing device\n"); 73 74 if (info == NULL) 75 return; 76 77 if (info->mtd) { 78 mtd_device_unregister(info->mtd); 79 map_destroy(info->mtd); 80 } 81 82 /* ensure ram is left read-only */ 83 84 platram_setrw(info, PLATRAM_RO); 85 86 kfree(info); 87 } 88 89 /* platram_probe 90 * 91 * called from device drive system when a device matching our 92 * driver is found. 93 */ 94 95 static int platram_probe(struct platform_device *pdev) 96 { 97 struct platdata_mtd_ram *pdata; 98 struct platram_info *info; 99 struct resource *res; 100 int err = 0; 101 102 dev_dbg(&pdev->dev, "probe entered\n"); 103 104 if (dev_get_platdata(&pdev->dev) == NULL) { 105 dev_err(&pdev->dev, "no platform data supplied\n"); 106 err = -ENOENT; 107 goto exit_error; 108 } 109 110 pdata = dev_get_platdata(&pdev->dev); 111 112 info = kzalloc(sizeof(*info), GFP_KERNEL); 113 if (info == NULL) { 114 err = -ENOMEM; 115 goto exit_error; 116 } 117 118 platform_set_drvdata(pdev, info); 119 120 info->dev = &pdev->dev; 121 info->pdata = pdata; 122 123 /* get the resource for the memory mapping */ 124 info->map.virt = devm_platform_get_and_ioremap_resource(pdev, 0, &res); 125 if (IS_ERR(info->map.virt)) { 126 err = PTR_ERR(info->map.virt); 127 goto exit_free; 128 } 129 130 dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res, 131 (unsigned long long)res->start); 132 133 /* setup map parameters */ 134 135 info->map.phys = res->start; 136 info->map.size = resource_size(res); 137 info->map.name = pdata->mapname != NULL ? 138 (char *)pdata->mapname : (char *)pdev->name; 139 info->map.bankwidth = pdata->bankwidth; 140 141 dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size); 142 143 simple_map_init(&info->map); 144 145 dev_dbg(&pdev->dev, "initialised map, probing for mtd\n"); 146 147 /* probe for the right mtd map driver 148 * supplied by the platform_data struct */ 149 150 if (pdata->map_probes) { 151 const char * const *map_probes = pdata->map_probes; 152 153 for ( ; !info->mtd && *map_probes; map_probes++) 154 info->mtd = do_map_probe(*map_probes , &info->map); 155 } 156 /* fallback to map_ram */ 157 else 158 info->mtd = do_map_probe("map_ram", &info->map); 159 160 if (info->mtd == NULL) { 161 dev_err(&pdev->dev, "failed to probe for map_ram\n"); 162 err = -ENOMEM; 163 goto exit_free; 164 } 165 166 info->mtd->dev.parent = &pdev->dev; 167 168 platram_setrw(info, PLATRAM_RW); 169 170 /* check to see if there are any available partitions, or whether 171 * to add this device whole */ 172 173 err = mtd_device_parse_register(info->mtd, pdata->probes, NULL, 174 pdata->partitions, 175 pdata->nr_partitions); 176 if (err) { 177 dev_err(&pdev->dev, "failed to register mtd device\n"); 178 goto exit_free; 179 } 180 181 dev_info(&pdev->dev, "registered mtd device\n"); 182 183 if (pdata->nr_partitions) { 184 /* add the whole device. */ 185 err = mtd_device_register(info->mtd, NULL, 0); 186 if (err) { 187 dev_err(&pdev->dev, 188 "failed to register the entire device\n"); 189 goto exit_free; 190 } 191 } 192 193 return 0; 194 195 exit_free: 196 platram_remove(pdev); 197 exit_error: 198 return err; 199 } 200 201 /* device driver info */ 202 203 /* work with hotplug and coldplug */ 204 MODULE_ALIAS("platform:mtd-ram"); 205 206 static struct platform_driver platram_driver = { 207 .probe = platram_probe, 208 .remove_new = platram_remove, 209 .driver = { 210 .name = "mtd-ram", 211 }, 212 }; 213 214 module_platform_driver(platram_driver); 215 216 MODULE_LICENSE("GPL"); 217 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); 218 MODULE_DESCRIPTION("MTD platform RAM map driver"); 219