1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * 4 * Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE 5 * Copyright (C) 2010 John Crispin <john@phrozen.org> 6 */ 7 8 #include <linux/err.h> 9 #include <linux/module.h> 10 #include <linux/types.h> 11 #include <linux/kernel.h> 12 #include <linux/io.h> 13 #include <linux/slab.h> 14 #include <linux/mtd/mtd.h> 15 #include <linux/mtd/map.h> 16 #include <linux/mtd/partitions.h> 17 #include <linux/mtd/cfi.h> 18 #include <linux/platform_device.h> 19 #include <linux/mtd/physmap.h> 20 #include <linux/of.h> 21 22 #include <lantiq_soc.h> 23 24 /* 25 * The NOR flash is connected to the same external bus unit (EBU) as PCI. 26 * To make PCI work we need to enable the endianness swapping for the address 27 * written to the EBU. This endianness swapping works for PCI correctly but 28 * fails for attached NOR devices. To workaround this we need to use a complex 29 * map. The workaround involves swapping all addresses whilst probing the chip. 30 * Once probing is complete we stop swapping the addresses but swizzle the 31 * unlock addresses to ensure that access to the NOR device works correctly. 32 */ 33 34 enum { 35 LTQ_NOR_PROBING, 36 LTQ_NOR_NORMAL 37 }; 38 39 struct ltq_mtd { 40 struct resource *res; 41 struct mtd_info *mtd; 42 struct map_info *map; 43 }; 44 45 static const char ltq_map_name[] = "ltq_nor"; 46 47 static map_word 48 ltq_read16(struct map_info *map, unsigned long adr) 49 { 50 unsigned long flags; 51 map_word temp; 52 53 if (map->map_priv_1 == LTQ_NOR_PROBING) 54 adr ^= 2; 55 spin_lock_irqsave(&ebu_lock, flags); 56 temp.x[0] = *(u16 *)(map->virt + adr); 57 spin_unlock_irqrestore(&ebu_lock, flags); 58 return temp; 59 } 60 61 static void 62 ltq_write16(struct map_info *map, map_word d, unsigned long adr) 63 { 64 unsigned long flags; 65 66 if (map->map_priv_1 == LTQ_NOR_PROBING) 67 adr ^= 2; 68 spin_lock_irqsave(&ebu_lock, flags); 69 *(u16 *)(map->virt + adr) = d.x[0]; 70 spin_unlock_irqrestore(&ebu_lock, flags); 71 } 72 73 /* 74 * The following 2 functions copy data between iomem and a cached memory 75 * section. As memcpy() makes use of pre-fetching we cannot use it here. 76 * The normal alternative of using memcpy_{to,from}io also makes use of 77 * memcpy() on MIPS so it is not applicable either. We are therefore stuck 78 * with having to use our own loop. 79 */ 80 static void 81 ltq_copy_from(struct map_info *map, void *to, 82 unsigned long from, ssize_t len) 83 { 84 unsigned char *f = (unsigned char *)map->virt + from; 85 unsigned char *t = (unsigned char *)to; 86 unsigned long flags; 87 88 spin_lock_irqsave(&ebu_lock, flags); 89 while (len--) 90 *t++ = *f++; 91 spin_unlock_irqrestore(&ebu_lock, flags); 92 } 93 94 static void 95 ltq_copy_to(struct map_info *map, unsigned long to, 96 const void *from, ssize_t len) 97 { 98 unsigned char *f = (unsigned char *)from; 99 unsigned char *t = (unsigned char *)map->virt + to; 100 unsigned long flags; 101 102 spin_lock_irqsave(&ebu_lock, flags); 103 while (len--) 104 *t++ = *f++; 105 spin_unlock_irqrestore(&ebu_lock, flags); 106 } 107 108 static int 109 ltq_mtd_probe(struct platform_device *pdev) 110 { 111 struct ltq_mtd *ltq_mtd; 112 struct cfi_private *cfi; 113 int err; 114 115 ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL); 116 if (!ltq_mtd) 117 return -ENOMEM; 118 119 platform_set_drvdata(pdev, ltq_mtd); 120 121 ltq_mtd->map->virt = devm_platform_get_and_ioremap_resource(pdev, 0, <q_mtd->res); 122 if (IS_ERR(ltq_mtd->map->virt)) 123 return PTR_ERR(ltq_mtd->map->virt); 124 125 ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info), 126 GFP_KERNEL); 127 if (!ltq_mtd->map) 128 return -ENOMEM; 129 130 ltq_mtd->map->phys = ltq_mtd->res->start; 131 ltq_mtd->map->size = resource_size(ltq_mtd->res); 132 133 ltq_mtd->map->name = ltq_map_name; 134 ltq_mtd->map->bankwidth = 2; 135 ltq_mtd->map->read = ltq_read16; 136 ltq_mtd->map->write = ltq_write16; 137 ltq_mtd->map->copy_from = ltq_copy_from; 138 ltq_mtd->map->copy_to = ltq_copy_to; 139 140 ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING; 141 ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map); 142 ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL; 143 144 if (!ltq_mtd->mtd) { 145 dev_err(&pdev->dev, "probing failed\n"); 146 return -ENXIO; 147 } 148 149 ltq_mtd->mtd->dev.parent = &pdev->dev; 150 mtd_set_of_node(ltq_mtd->mtd, pdev->dev.of_node); 151 152 cfi = ltq_mtd->map->fldrv_priv; 153 cfi->addr_unlock1 ^= 1; 154 cfi->addr_unlock2 ^= 1; 155 156 err = mtd_device_register(ltq_mtd->mtd, NULL, 0); 157 if (err) { 158 dev_err(&pdev->dev, "failed to add partitions\n"); 159 goto err_destroy; 160 } 161 162 return 0; 163 164 err_destroy: 165 map_destroy(ltq_mtd->mtd); 166 return err; 167 } 168 169 static int 170 ltq_mtd_remove(struct platform_device *pdev) 171 { 172 struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev); 173 174 if (ltq_mtd && ltq_mtd->mtd) { 175 mtd_device_unregister(ltq_mtd->mtd); 176 map_destroy(ltq_mtd->mtd); 177 } 178 return 0; 179 } 180 181 static const struct of_device_id ltq_mtd_match[] = { 182 { .compatible = "lantiq,nor" }, 183 {}, 184 }; 185 MODULE_DEVICE_TABLE(of, ltq_mtd_match); 186 187 static struct platform_driver ltq_mtd_driver = { 188 .probe = ltq_mtd_probe, 189 .remove = ltq_mtd_remove, 190 .driver = { 191 .name = "ltq-nor", 192 .of_match_table = ltq_mtd_match, 193 }, 194 }; 195 196 module_platform_driver(ltq_mtd_driver); 197 198 MODULE_LICENSE("GPL"); 199 MODULE_AUTHOR("John Crispin <john@phrozen.org>"); 200 MODULE_DESCRIPTION("Lantiq SoC NOR"); 201