diff options
Diffstat (limited to 'drivers/mtd/maps/lantiq-flash.c')
| -rw-r--r-- | drivers/mtd/maps/lantiq-flash.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/drivers/mtd/maps/lantiq-flash.c b/drivers/mtd/maps/lantiq-flash.c new file mode 100644 index 000000000..67a1dbfdd --- /dev/null +++ b/drivers/mtd/maps/lantiq-flash.c @@ -0,0 +1,205 @@ +// 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->res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!ltq_mtd->res) { + dev_err(&pdev->dev, "failed to get memory resource\n"); + return -ENOENT; + } + + 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->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res); + if (IS_ERR(ltq_mtd->map->virt)) + return PTR_ERR(ltq_mtd->map->virt); + + 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 int +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); + } + return 0; +} + +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 = 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"); |