Commit 660685d9 authored by Artem Bityutskiy's avatar Artem Bityutskiy Committed by David Woodhouse
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mtd: merge mtdchar module with mtdcore 



The MTD subsystem has historically tried to be as configurable as possible. The
side-effect of this is that its configuration menu is rather large, and we are
gradually shrinking it. For example, we recently merged partitions support with
the mtdcore.

This patch does the next step - it merges the mtdchar module to mtdcore. And in
this case this is not only about eliminating too fine-grained separation and
simplifying the configuration menu. This is also about eliminating seemingly
useless kernel module.

Indeed, mtdchar is a module that allows user-space making use of MTD devices
via /dev/mtd* character devices. If users do not enable it, they simply cannot
use MTD devices at all. They cannot read or write the flash contents. Is it a
sane and useful setup? I believe not. And everyone just enables mtdchar.

Having mtdchar separate is also a little bit harmful. People sometimes miss the
fact that they need to enable an additional configuration option to have
user-space MTD interfaces, and then they wonder why on earth the kernel does
not allow using the flash? They spend time asking around.

Thus, let's just get rid of this module and make it part of mtd core.

Note, mtdchar had additional configuration option to enable OTP interfaces,
which are present on some flashes. I removed that option as well - it saves a
really tiny amount space.

[dwmw2: Strictly speaking, you can mount file systems on MTD devices just
        fine without the mtdchar (or mtdblock) devices; you just can't do
        other manipulations directly on the underlying device. But still I
        agree that it makes sense to make this unconditional. And Yay! we
        get to kill off an instance of checking CONFIG_foo_MODULE, which is
        an abomination that should never happen.]

Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent cb70783c

drivers/mtd/Kconfig

+0 −13
Original line number Diff line number Diff line
@@ -157,19 +157,6 @@ config MTD_BCM47XX_PARTS 


comment "User Modules And Translation Layers"



config MTD_CHAR

	tristate "Direct char device access to MTD devices"

	help

	  This provides a character device for each MTD device present in

	  the system, allowing the user to read and write directly to the

	  memory chips, and also use ioctl() to obtain information about

	  the device, or to erase parts of it.



config HAVE_MTD_OTP

	bool

	help

	  Enable access to OTP regions using MTD_CHAR.



config MTD_BLKDEVS

	tristate "Common interface to block layer for MTD 'translation layers'"

	depends on BLOCK

drivers/mtd/Makefile

+1 −2
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ 


# Core functionality.

obj-$(CONFIG_MTD)		+= mtd.o

mtd-y				:= mtdcore.o mtdsuper.o mtdconcat.o mtdpart.o

mtd-y				:= mtdcore.o mtdsuper.o mtdconcat.o mtdpart.o mtdchar.o



obj-$(CONFIG_MTD_OF_PARTS)	+= ofpart.o

obj-$(CONFIG_MTD_REDBOOT_PARTS) += redboot.o
@@ -15,7 +15,6 @@ obj-$(CONFIG_MTD_BCM63XX_PARTS) += bcm63xxpart.o 
obj-$(CONFIG_MTD_BCM47XX_PARTS)	+= bcm47xxpart.o



# 'Users' - code which presents functionality to userspace.

obj-$(CONFIG_MTD_CHAR)		+= mtdchar.o

obj-$(CONFIG_MTD_BLKDEVS)	+= mtd_blkdevs.o

obj-$(CONFIG_MTD_BLOCK)		+= mtdblock.o

obj-$(CONFIG_MTD_BLOCK_RO)	+= mtdblock_ro.o

drivers/mtd/chips/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -146,7 +146,6 @@ config MTD_CFI_I8 
config MTD_OTP

	bool "Protection Registers aka one-time programmable (OTP) bits"

	depends on MTD_CFI_ADV_OPTIONS

	select HAVE_MTD_OTP

	default n

	help

	  This enables support for reading, writing and locking so called

drivers/mtd/devices/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -71,7 +71,6 @@ config MTD_DATAFLASH_WRITE_VERIFY 
config MTD_DATAFLASH_OTP

	bool "DataFlash OTP support (Security Register)"

	depends on MTD_DATAFLASH

	select HAVE_MTD_OTP

	help

	  Newer DataFlash chips (revisions C and D) support 128 bytes of

	  one-time-programmable (OTP) data.  The first half may be written

drivers/mtd/mtdchar.c

+4 −16
Original line number Diff line number Diff line
@@ -38,6 +38,8 @@ 


#include <asm/uaccess.h>



#include "mtdcore.h"



static DEFINE_MUTEX(mtd_mutex);



/*
@@ -365,7 +367,6 @@ static void mtdchar_erase_callback (struct erase_info *instr) 
	wake_up((wait_queue_head_t *)instr->priv);

}



#ifdef CONFIG_HAVE_MTD_OTP

static int otp_select_filemode(struct mtd_file_info *mfi, int mode)

{

	struct mtd_info *mtd = mfi->mtd;
@@ -395,9 +396,6 @@ static int otp_select_filemode(struct mtd_file_info *mfi, int mode) 


	return 0;

}

#else

# define otp_select_filemode(f,m)	-EOPNOTSUPP

#endif



static int mtdchar_writeoob(struct file *file, struct mtd_info *mtd,

	uint64_t start, uint32_t length, void __user *ptr,
@@ -890,7 +888,6 @@ static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg) 
		break;

	}



#ifdef CONFIG_HAVE_MTD_OTP

	case OTPSELECT:

	{

		int mode;
@@ -946,7 +943,6 @@ static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg) 
		ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);

		break;

	}

#endif



	/* This ioctl is being deprecated - it truncates the ECC layout */

	case ECCGETLAYOUT:
@@ -1242,7 +1238,7 @@ static struct file_system_type mtd_inodefs_type = { 
};

MODULE_ALIAS_FS("mtd_inodefs");



static int __init init_mtdchar(void)

int __init init_mtdchar(void)

{

	int ret;
@@ -1268,18 +1264,10 @@ err_unregister_chdev: 
	return ret;

}



static void __exit cleanup_mtdchar(void)

void __exit cleanup_mtdchar(void)

{

	unregister_filesystem(&mtd_inodefs_type);

	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");

}



module_init(init_mtdchar);

module_exit(cleanup_mtdchar);



MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");

MODULE_DESCRIPTION("Direct character-device access to MTD devices");

MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);

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