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// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE
* Copyright (C) 2010 John Crispin <john@phrozen.org>
*/
#include <linux/err.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/cfi.h>
#include <linux/platform_device.h>
#include <linux/mtd/physmap.h>
#include <linux/of.h>
#include <lantiq_soc.h>
/*
* The NOR flash is connected to the same external bus unit (EBU) as PCI.
* To make PCI work we need to enable the endianness swapping for the address
* written to the EBU. This endianness swapping works for PCI correctly but
* fails for attached NOR devices. To workaround this we need to use a complex
* map. The workaround involves swapping all addresses whilst probing the chip.
* Once probing is complete we stop swapping the addresses but swizzle the
* unlock addresses to ensure that access to the NOR device works correctly.
*/
enum {
LTQ_NOR_PROBING,
LTQ_NOR_NORMAL
};
struct ltq_mtd {
struct resource *res;
struct mtd_info *mtd;
struct map_info *map;
};
static const char ltq_map_name[] = "ltq_nor";
static map_word
ltq_read16(struct map_info *map, unsigned long adr)
{
unsigned long flags;
map_word temp;
if (map->map_priv_1 == LTQ_NOR_PROBING)
adr ^= 2;
spin_lock_irqsave(&ebu_lock, flags);
temp.x[0] = *(u16 *)(map->virt + adr);
spin_unlock_irqrestore(&ebu_lock, flags);
return temp;
}
static void
ltq_write16(struct map_info *map, map_word d, unsigned long adr)
{
unsigned long flags;
if (map->map_priv_1 == LTQ_NOR_PROBING)
adr ^= 2;
spin_lock_irqsave(&ebu_lock, flags);
*(u16 *)(map->virt + adr) = d.x[0];
spin_unlock_irqrestore(&ebu_lock, flags);
}
/*
* The following 2 functions copy data between iomem and a cached memory
* section. As memcpy() makes use of pre-fetching we cannot use it here.
* The normal alternative of using memcpy_{to,from}io also makes use of
* memcpy() on MIPS so it is not applicable either. We are therefore stuck
* with having to use our own loop.
*/
static void
ltq_copy_from(struct map_info *map, void *to,
unsigned long from, ssize_t len)
{
unsigned char *f = (unsigned char *)map->virt + from;
unsigned char *t = (unsigned char *)to;
unsigned long flags;
spin_lock_irqsave(&ebu_lock, flags);
while (len--)
*t++ = *f++;
spin_unlock_irqrestore(&ebu_lock, flags);
}
static void
ltq_copy_to(struct map_info *map, unsigned long to,
const void *from, ssize_t len)
{
unsigned char *f = (unsigned char *)from;
unsigned char *t = (unsigned char *)map->virt + to;
unsigned long flags;
spin_lock_irqsave(&ebu_lock, flags);
while (len--)
*t++ = *f++;
spin_unlock_irqrestore(&ebu_lock, flags);
}
static int
ltq_mtd_probe(struct platform_device *pdev)
{
struct ltq_mtd *ltq_mtd;
struct cfi_private *cfi;
int err;
ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL);
if (!ltq_mtd)
return -ENOMEM;
platform_set_drvdata(pdev, ltq_mtd);
ltq_mtd->map->virt = devm_platform_get_and_ioremap_resource(pdev, 0, <q_mtd->res);
if (IS_ERR(ltq_mtd->map->virt))
return PTR_ERR(ltq_mtd->map->virt);
ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
GFP_KERNEL);
if (!ltq_mtd->map)
return -ENOMEM;
ltq_mtd->map->phys = ltq_mtd->res->start;
ltq_mtd->map->size = resource_size(ltq_mtd->res);
ltq_mtd->map->name = ltq_map_name;
ltq_mtd->map->bankwidth = 2;
ltq_mtd->map->read = ltq_read16;
ltq_mtd->map->write = ltq_write16;
ltq_mtd->map->copy_from = ltq_copy_from;
ltq_mtd->map->copy_to = ltq_copy_to;
ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
if (!ltq_mtd->mtd) {
dev_err(&pdev->dev, "probing failed\n");
return -ENXIO;
}
ltq_mtd->mtd->dev.parent = &pdev->dev;
mtd_set_of_node(ltq_mtd->mtd, pdev->dev.of_node);
cfi = ltq_mtd->map->fldrv_priv;
cfi->addr_unlock1 ^= 1;
cfi->addr_unlock2 ^= 1;
err = mtd_device_register(ltq_mtd->mtd, NULL, 0);
if (err) {
dev_err(&pdev->dev, "failed to add partitions\n");
goto err_destroy;
}
return 0;
err_destroy:
map_destroy(ltq_mtd->mtd);
return err;
}
static void ltq_mtd_remove(struct platform_device *pdev)
{
struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
if (ltq_mtd && ltq_mtd->mtd) {
mtd_device_unregister(ltq_mtd->mtd);
map_destroy(ltq_mtd->mtd);
}
}
static const struct of_device_id ltq_mtd_match[] = {
{ .compatible = "lantiq,nor" },
{},
};
MODULE_DEVICE_TABLE(of, ltq_mtd_match);
static struct platform_driver ltq_mtd_driver = {
.probe = ltq_mtd_probe,
.remove_new = ltq_mtd_remove,
.driver = {
.name = "ltq-nor",
.of_match_table = ltq_mtd_match,
},
};
module_platform_driver(ltq_mtd_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("John Crispin <john@phrozen.org>");
MODULE_DESCRIPTION("Lantiq SoC NOR");
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