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Linux/drivers/mtd/maps/lantiq-flash.c

  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 <blogic@openwrt.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         if (of_machine_is_compatible("lantiq,falcon") &&
118                         (ltq_boot_select() != BS_FLASH)) {
119                 dev_err(&pdev->dev, "invalid bootstrap options\n");
120                 return -ENODEV;
121         }
122 
123         ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL);
124         if (!ltq_mtd)
125                 return -ENOMEM;
126 
127         platform_set_drvdata(pdev, ltq_mtd);
128 
129         ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
130         if (!ltq_mtd->res) {
131                 dev_err(&pdev->dev, "failed to get memory resource\n");
132                 return -ENOENT;
133         }
134 
135         ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
136                                     GFP_KERNEL);
137         if (!ltq_mtd->map)
138                 return -ENOMEM;
139 
140         ltq_mtd->map->phys = ltq_mtd->res->start;
141         ltq_mtd->map->size = resource_size(ltq_mtd->res);
142         ltq_mtd->map->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res);
143         if (IS_ERR(ltq_mtd->map->virt))
144                 return PTR_ERR(ltq_mtd->map->virt);
145 
146         ltq_mtd->map->name = ltq_map_name;
147         ltq_mtd->map->bankwidth = 2;
148         ltq_mtd->map->read = ltq_read16;
149         ltq_mtd->map->write = ltq_write16;
150         ltq_mtd->map->copy_from = ltq_copy_from;
151         ltq_mtd->map->copy_to = ltq_copy_to;
152 
153         ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
154         ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
155         ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
156 
157         if (!ltq_mtd->mtd) {
158                 dev_err(&pdev->dev, "probing failed\n");
159                 return -ENXIO;
160         }
161 
162         ltq_mtd->mtd->dev.parent = &pdev->dev;
163         mtd_set_of_node(ltq_mtd->mtd, pdev->dev.of_node);
164 
165         cfi = ltq_mtd->map->fldrv_priv;
166         cfi->addr_unlock1 ^= 1;
167         cfi->addr_unlock2 ^= 1;
168 
169         err = mtd_device_register(ltq_mtd->mtd, NULL, 0);
170         if (err) {
171                 dev_err(&pdev->dev, "failed to add partitions\n");
172                 goto err_destroy;
173         }
174 
175         return 0;
176 
177 err_destroy:
178         map_destroy(ltq_mtd->mtd);
179         return err;
180 }
181 
182 static int
183 ltq_mtd_remove(struct platform_device *pdev)
184 {
185         struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
186 
187         if (ltq_mtd && ltq_mtd->mtd) {
188                 mtd_device_unregister(ltq_mtd->mtd);
189                 map_destroy(ltq_mtd->mtd);
190         }
191         return 0;
192 }
193 
194 static const struct of_device_id ltq_mtd_match[] = {
195         { .compatible = "lantiq,nor" },
196         {},
197 };
198 MODULE_DEVICE_TABLE(of, ltq_mtd_match);
199 
200 static struct platform_driver ltq_mtd_driver = {
201         .probe = ltq_mtd_probe,
202         .remove = ltq_mtd_remove,
203         .driver = {
204                 .name = "ltq-nor",
205                 .of_match_table = ltq_mtd_match,
206         },
207 };
208 
209 module_platform_driver(ltq_mtd_driver);
210 
211 MODULE_LICENSE("GPL");
212 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
213 MODULE_DESCRIPTION("Lantiq SoC NOR");
214 

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