kernel/linux.git/drivers/mtd/mtdchar.c, branch v3.15.2

mtd: Fix the behavior of OTP write if there is not enough room for data

2014-03-11T05:42:31+00:00

If a write to one time programmable memory (OTP) hits the end of this memory area, no more data can be written. The count variable in mtdchar_write() in drivers/mtd/mtdchar.c is not decreased anymore. We are trapped in the loop forever, mtdchar_write() will never return in this case. The desired behavior of a write in such a case is described in [1]: - Try to write as much data as possible, truncate the write to fit into the available memory and return the number of bytes that actually have been written. - If no data could be written at all, return -ENOSPC. This patch fixes the behavior of OTP write if there is not enough space for all data: 1) mtd_write_user_prot_reg() in drivers/mtd/mtdcore.c is modified to return -ENOSPC if no data could be written at all. 2) mtdchar_write() is modified to handle -ENOSPC correctly. Exit if a write returned -ENOSPC and yield the correct return value, either then number of bytes that could be written, or -ENOSPC, if no data could be written at all. Furthermore the patch harmonizes the behavior of the OTP memory write in drivers/mtd/devices/mtd_dataflash.c with the other implementations and the requirements from [1]. Instead of returning -EINVAL if the data does not fit into the OTP memory, we try to write as much data as possible/truncate the write. [1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/write.html Signed-off-by: Christian Riesch Signed-off-by: Brian Norris

mtd: Add a retlen parameter to _get_{fact,user}_prot_info

2014-03-11T05:42:28+00:00

Signed-off-by: Christian Riesch Cc: Artem Bityutskiy Signed-off-by: Brian Norris

mtd: mtdchar: return expected errors on mmap() call

2013-11-11T19:18:15+00:00

According both to POSIX.1-2008 and Linux Programmer's Manual mmap() syscall shouldn't return undocumented ENOSYS, this change replaces the errno with more appropriate ENODEV and EACCESS. Signed-off-by: Vladimir Zapolskiy Cc: David Woodhouse Signed-off-by: Brian Norris

mtd: Move major number definitions to major.h

2013-11-07T07:32:59+00:00

This patch moves the char and block major number definitions to major.h to be with the rest of the major numbers. While doing this, include major.h in the files that need it. Signed-off-by: Ezequiel Garcia Signed-off-by: Brian Norris

mtdchar: switch to fixed_size_llseek()

2013-06-29T08:57:27+00:00

Signed-off-by: Al Viro

Merge tag 'for-linus-20130509' of git://git.infradead.org/linux-mtd

2013-05-09T17:15:46+00:00

Pull MTD update from David Woodhouse: - Lots of cleanups from Artem, including deletion of some obsolete drivers - Support partitions larger than 4GiB in device tree - Support for new SPI chips * tag 'for-linus-20130509' of git://git.infradead.org/linux-mtd: (83 commits) mtd: omap2: Use module_platform_driver() mtd: bf5xx_nand: Use module_platform_driver() mtd: denali_dt: Remove redundant use of of_match_ptr mtd: denali_dt: Change return value to fix smatch warning mtd: denali_dt: Use module_platform_driver() mtd: denali_dt: Fix incorrect error check mtd: nand: subpage write support for hardware based ECC schemes mtd: omap2: use msecs_to_jiffies() mtd: nand_ids: use size macros mtd: nand_ids: improve LEGACY_ID_NAND macro a bit mtd: add 4 Toshiba nand chips for the full-id case mtd: add the support to parse out the full-id nand type mtd: add new fields to nand_flash_dev{} mtd: sh_flctl: Use of_match_ptr() macro mtd: gpio: Use of_match_ptr() macro mtd: gpio: Use devm_kzalloc() mtd: davinci_nand: Use of_match_ptr() mtd: dataflash: Use of_match_ptr() macro mtd: remove h720x flash support mtd: onenand: remove OneNAND simulator ...

mtdchar: remove no-longer-used vma helpers

2013-04-19T17:05:39+00:00

With the conversion to vm_iomap_memory(), these vma helpers are no longer used. Signed-off-by: Linus Torvalds

vm: convert mtdchar mmap to vm_iomap_memory() helper

2013-04-19T16:53:07+00:00

This is my example conversion of a few existing mmap users. The mtdchar case is actually disabled right now (and stays disabled), but I did it because it showed up on my "git grep", and I was familiar with the code due to fixing an overflow problem in the code in commit 9c603e53d380 ("mtdchar: fix offset overflow detection"). Signed-off-by: Linus Torvalds

mtd: merge mtdchar module with mtdcore

2013-04-05T12:16:54+00:00

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: Artem Bityutskiy Signed-off-by: David Woodhouse

mtd: mtdchar: use proper kernel print level

2013-04-05T12:15:38+00:00

We normally use 'pr_err()' for error messages, not 'pr_notice()'. Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse