1 /* 2 * This program is free software; you can redistribute it and/or modify it 3 * under the terms of the GNU General Public License version 2 as published 4 * by the Free Software Foundation. 5 * 6 * Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE 7 * Copyright (C) 2010 John Crispin <john@phrozen.org> 8 */ 9 10 #include <linux/err.h> 11 #include <linux/module.h> 12 #include <linux/types.h> 13 #include <linux/kernel.h> 14 #include <linux/io.h> 15 #include <linux/slab.h> 16 #include <linux/mtd/mtd.h> 17 #include <linux/mtd/map.h> 18 #include <linux/mtd/partitions.h> 19 #include <linux/mtd/cfi.h> 20 #include <linux/platform_device.h> 21 #include <linux/mtd/physmap.h> 22 #include <linux/of.h> 23 24 #include <lantiq_soc.h> 25 26 /* 27 * The NOR flash is connected to the same external bus unit (EBU) as PCI. 28 * To make PCI work we need to enable the endianness swapping for the address 29 * written to the EBU. This endianness swapping works for PCI correctly but 30 * fails for attached NOR devices. To workaround this we need to use a complex 31 * map. The workaround involves swapping all addresses whilst probing the chip. 32 * Once probing is complete we stop swapping the addresses but swizzle the 33 * unlock addresses to ensure that access to the NOR device works correctly. 34 */ 35 36 enum { 37 LTQ_NOR_PROBING, 38 LTQ_NOR_NORMAL 39 }; 40 41 struct ltq_mtd { 42 struct resource *res; 43 struct mtd_info *mtd; 44 struct map_info *map; 45 }; 46 47 static const char ltq_map_name[] = "ltq_nor"; 48 49 static map_word 50 ltq_read16(struct map_info *map, unsigned long adr) 51 { 52 unsigned long flags; 53 map_word temp; 54 55 if (map->map_priv_1 == LTQ_NOR_PROBING) 56 adr ^= 2; 57 spin_lock_irqsave(&ebu_lock, flags); 58 temp.x[0] = *(u16 *)(map->virt + adr); 59 spin_unlock_irqrestore(&ebu_lock, flags); 60 return temp; 61 } 62 63 static void 64 ltq_write16(struct map_info *map, map_word d, unsigned long adr) 65 { 66 unsigned long flags; 67 68 if (map->map_priv_1 == LTQ_NOR_PROBING) 69 adr ^= 2; 70 spin_lock_irqsave(&ebu_lock, flags); 71 *(u16 *)(map->virt + adr) = d.x[0]; 72 spin_unlock_irqrestore(&ebu_lock, flags); 73 } 74 75 /* 76 * The following 2 functions copy data between iomem and a cached memory 77 * section. As memcpy() makes use of pre-fetching we cannot use it here. 78 * The normal alternative of using memcpy_{to,from}io also makes use of 79 * memcpy() on MIPS so it is not applicable either. We are therefore stuck 80 * with having to use our own loop. 81 */ 82 static void 83 ltq_copy_from(struct map_info *map, void *to, 84 unsigned long from, ssize_t len) 85 { 86 unsigned char *f = (unsigned char *)map->virt + from; 87 unsigned char *t = (unsigned char *)to; 88 unsigned long flags; 89 90 spin_lock_irqsave(&ebu_lock, flags); 91 while (len--) 92 *t++ = *f++; 93 spin_unlock_irqrestore(&ebu_lock, flags); 94 } 95 96 static void 97 ltq_copy_to(struct map_info *map, unsigned long to, 98 const void *from, ssize_t len) 99 { 100 unsigned char *f = (unsigned char *)from; 101 unsigned char *t = (unsigned char *)map->virt + to; 102 unsigned long flags; 103 104 spin_lock_irqsave(&ebu_lock, flags); 105 while (len--) 106 *t++ = *f++; 107 spin_unlock_irqrestore(&ebu_lock, flags); 108 } 109 110 static int 111 ltq_mtd_probe(struct platform_device *pdev) 112 { 113 struct ltq_mtd *ltq_mtd; 114 struct cfi_private *cfi; 115 int err; 116 117 ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL); 118 if (!ltq_mtd) 119 return -ENOMEM; 120 121 platform_set_drvdata(pdev, ltq_mtd); 122 123 ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 124 if (!ltq_mtd->res) { 125 dev_err(&pdev->dev, "failed to get memory resource\n"); 126 return -ENOENT; 127 } 128 129 ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info), 130 GFP_KERNEL); 131 if (!ltq_mtd->map) 132 return -ENOMEM; 133 134 ltq_mtd->map->phys = ltq_mtd->res->start; 135 ltq_mtd->map->size = resource_size(ltq_mtd->res); 136 ltq_mtd->map->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res); 137 if (IS_ERR(ltq_mtd->map->virt)) 138 return PTR_ERR(ltq_mtd->map->virt); 139 140 ltq_mtd->map->name = ltq_map_name; 141 ltq_mtd->map->bankwidth = 2; 142 ltq_mtd->map->read = ltq_read16; 143 ltq_mtd->map->write = ltq_write16; 144 ltq_mtd->map->copy_from = ltq_copy_from; 145 ltq_mtd->map->copy_to = ltq_copy_to; 146 147 ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING; 148 ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map); 149 ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL; 150 151 if (!ltq_mtd->mtd) { 152 dev_err(&pdev->dev, "probing failed\n"); 153 return -ENXIO; 154 } 155 156 ltq_mtd->mtd->dev.parent = &pdev->dev; 157 mtd_set_of_node(ltq_mtd->mtd, pdev->dev.of_node); 158 159 cfi = ltq_mtd->map->fldrv_priv; 160 cfi->addr_unlock1 ^= 1; 161 cfi->addr_unlock2 ^= 1; 162 163 err = mtd_device_register(ltq_mtd->mtd, NULL, 0); 164 if (err) { 165 dev_err(&pdev->dev, "failed to add partitions\n"); 166 goto err_destroy; 167 } 168 169 return 0; 170 171 err_destroy: 172 map_destroy(ltq_mtd->mtd); 173 return err; 174 } 175 176 static int 177 ltq_mtd_remove(struct platform_device *pdev) 178 { 179 struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev); 180 181 if (ltq_mtd && ltq_mtd->mtd) { 182 mtd_device_unregister(ltq_mtd->mtd); 183 map_destroy(ltq_mtd->mtd); 184 } 185 return 0; 186 } 187 188 static const struct of_device_id ltq_mtd_match[] = { 189 { .compatible = "lantiq,nor" }, 190 {}, 191 }; 192 MODULE_DEVICE_TABLE(of, ltq_mtd_match); 193 194 static struct platform_driver ltq_mtd_driver = { 195 .probe = ltq_mtd_probe, 196 .remove = ltq_mtd_remove, 197 .driver = { 198 .name = "ltq-nor", 199 .of_match_table = ltq_mtd_match, 200 }, 201 }; 202 203 module_platform_driver(ltq_mtd_driver); 204 205 MODULE_LICENSE("GPL"); 206 MODULE_AUTHOR("John Crispin <john@phrozen.org>"); 207 MODULE_DESCRIPTION("Lantiq SoC NOR"); 208