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1// SPDX-License-Identifier: GPL-2.0-only2/*3 *4 * Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE5 * 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 address27 * written to the EBU. This endianness swapping works for PCI correctly but28 * fails for attached NOR devices. To workaround this we need to use a complex29 * map. The workaround involves swapping all addresses whilst probing the chip.30 * Once probing is complete we stop swapping the addresses but swizzle the31 * unlock addresses to ensure that access to the NOR device works correctly.32 */33 34enum {35 LTQ_NOR_PROBING,36 LTQ_NOR_NORMAL37};38 39struct ltq_mtd {40 struct resource *res;41 struct mtd_info *mtd;42 struct map_info *map;43};44 45static const char ltq_map_name[] = "ltq_nor";46 47static map_word48ltq_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 61static void62ltq_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 memory75 * 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 of77 * memcpy() on MIPS so it is not applicable either. We are therefore stuck78 * with having to use our own loop.79 */80static void81ltq_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 94static void95ltq_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 108static int109ltq_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 164err_destroy:165 map_destroy(ltq_mtd->mtd);166 return err;167}168 169static void ltq_mtd_remove(struct platform_device *pdev)170{171 struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);172 173 if (ltq_mtd && ltq_mtd->mtd) {174 mtd_device_unregister(ltq_mtd->mtd);175 map_destroy(ltq_mtd->mtd);176 }177}178 179static const struct of_device_id ltq_mtd_match[] = {180 { .compatible = "lantiq,nor" },181 {},182};183MODULE_DEVICE_TABLE(of, ltq_mtd_match);184 185static struct platform_driver ltq_mtd_driver = {186 .probe = ltq_mtd_probe,187 .remove_new = ltq_mtd_remove,188 .driver = {189 .name = "ltq-nor",190 .of_match_table = ltq_mtd_match,191 },192};193 194module_platform_driver(ltq_mtd_driver);195 196MODULE_LICENSE("GPL");197MODULE_AUTHOR("John Crispin <john@phrozen.org>");198MODULE_DESCRIPTION("Lantiq SoC NOR");199