From 2b533e775aec580cf60074417f4ca00ac9cf3580 Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Fri, 3 Jul 2026 13:35:47 +0200 Subject: [PATCH] Revert "mtd: maps: remove uclinux map driver" MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The uclinux MTD map driver is still actively used on ColdFire (m68k) platforms. The ColdFire startup code in arch/m68k/coldfire/head.S copies an attached filesystem blob to _bss_stop, and the uclinux driver picks it up from there. Most ColdFire defconfigs enable CONFIG_MTD_UCLINUX, as the driver seems to serve as a replacement for CONFIG_BLK_DEV_INITRD on these non-MMU targets. The driver was removed as part of a series cleaning up AMD Élan specific drivers, but unlike the other three drivers in that series, this driver seemed to not be as Élan specific (nor unused) as initially thought. This reverts commit c584b8a7ad01a334a89732f3c5791ba14e58642b. Reported-by: Greg Ungerer Closes: https://lore.kernel.org/all/b55ac37f-4523-46d0-8e77-3a17d7235ffe@westnet.com.au/ Acked-by: Arnd Bergmann Signed-off-by: Miquel Raynal --- drivers/mtd/maps/Kconfig | 6 ++ drivers/mtd/maps/Makefile | 1 + drivers/mtd/maps/uclinux.c | 118 +++++++++++++++++++++++++++++++++++++ 3 files changed, 125 insertions(+) create mode 100644 drivers/mtd/maps/uclinux.c diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig index dce5e67ce3c2..f447902d707e 100644 --- a/drivers/mtd/maps/Kconfig +++ b/drivers/mtd/maps/Kconfig @@ -277,6 +277,12 @@ config MTD_PCMCIA_ANONYMOUS If unsure, say N. +config MTD_UCLINUX + bool "Generic uClinux RAM/ROM filesystem support" + depends on (MTD_RAM=y || MTD_ROM=y) && (!MMU || COLDFIRE) + help + Map driver to support image based filesystems for uClinux. + config MTD_PLATRAM tristate "Map driver for platform device RAM (mtd-ram)" select MTD_RAM diff --git a/drivers/mtd/maps/Makefile b/drivers/mtd/maps/Makefile index fbed278157f6..01745eca1f73 100644 --- a/drivers/mtd/maps/Makefile +++ b/drivers/mtd/maps/Makefile @@ -30,6 +30,7 @@ obj-$(CONFIG_MTD_SUN_UFLASH) += sun_uflash.o obj-$(CONFIG_MTD_SCx200_DOCFLASH)+= scx200_docflash.o obj-$(CONFIG_MTD_SOLUTIONENGINE)+= solutionengine.o obj-$(CONFIG_MTD_PCI) += pci.o +obj-$(CONFIG_MTD_UCLINUX) += uclinux.o obj-$(CONFIG_MTD_SCB2_FLASH) += scb2_flash.o obj-$(CONFIG_MTD_PLATRAM) += plat-ram.o obj-$(CONFIG_MTD_VMU) += vmu-flash.o diff --git a/drivers/mtd/maps/uclinux.c b/drivers/mtd/maps/uclinux.c new file mode 100644 index 000000000000..de4c46318abb --- /dev/null +++ b/drivers/mtd/maps/uclinux.c @@ -0,0 +1,118 @@ +/****************************************************************************/ + +/* + * uclinux.c -- generic memory mapped MTD driver for uclinux + * + * (C) Copyright 2002, Greg Ungerer (gerg@snapgear.com) + * + * License: GPL + */ + +/****************************************************************************/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/****************************************************************************/ + +#ifdef CONFIG_MTD_ROM +#define MAP_NAME "rom" +#else +#define MAP_NAME "ram" +#endif + +static struct map_info uclinux_ram_map = { + .name = MAP_NAME, + .size = 0, +}; + +static unsigned long physaddr = -1; +module_param(physaddr, ulong, S_IRUGO); + +static struct mtd_info *uclinux_ram_mtdinfo; + +/****************************************************************************/ + +static const struct mtd_partition uclinux_romfs[] = { + { .name = "ROMfs" } +}; + +#define NUM_PARTITIONS ARRAY_SIZE(uclinux_romfs) + +/****************************************************************************/ + +static int uclinux_point(struct mtd_info *mtd, loff_t from, size_t len, + size_t *retlen, void **virt, resource_size_t *phys) +{ + struct map_info *map = mtd->priv; + *virt = map->virt + from; + if (phys) + *phys = map->phys + from; + *retlen = len; + return(0); +} + +/****************************************************************************/ + +static int __init uclinux_mtd_init(void) +{ + struct mtd_info *mtd; + struct map_info *mapp; + + mapp = &uclinux_ram_map; + + if (physaddr == -1) + mapp->phys = (resource_size_t)__bss_stop; + else + mapp->phys = physaddr; + + if (!mapp->size) + mapp->size = PAGE_ALIGN(ntohl(*((unsigned long *)(mapp->phys + 8)))); + mapp->bankwidth = 4; + + printk("uclinux[mtd]: probe address=0x%x size=0x%x\n", + (int) mapp->phys, (int) mapp->size); + + /* + * The filesystem is guaranteed to be in direct mapped memory. It is + * directly following the kernels own bss region. Following the same + * mechanism used by architectures setting up traditional initrds we + * use phys_to_virt to get the virtual address of its start. + */ + mapp->virt = phys_to_virt(mapp->phys); + + if (mapp->virt == 0) { + printk("uclinux[mtd]: no virtual mapping?\n"); + return(-EIO); + } + + simple_map_init(mapp); + + mtd = do_map_probe("map_" MAP_NAME, mapp); + if (!mtd) { + printk("uclinux[mtd]: failed to find a mapping?\n"); + return(-ENXIO); + } + + mtd->owner = THIS_MODULE; + mtd->_point = uclinux_point; + mtd->priv = mapp; + + uclinux_ram_mtdinfo = mtd; + mtd_device_register(mtd, uclinux_romfs, NUM_PARTITIONS); + + return(0); +} +device_initcall(uclinux_mtd_init); + +/****************************************************************************/ -- 2.47.3