mtd: ubi: allow UBI volumes to provide NVMEM
Subsystems (2)
cover mtd: ubi: allow UBI volumes to provide NVMEM
The series is a follow-up and contains all patches of the previous series "mtd: ubi: behave like a good MTD citizen"[1] which was meant in preparation for implementing the NVMEM provider.
The goal is to support embedded Linux devices which got NVMEM bits stored inside a UBI volume. Representing the UBI volume in the Device Tree, adding a phandle to be referenced by NVMEM consumers allows such devices to come up with their correct MAC addresses and device-specific Wi-Fi calibration data loaded.
In order to be available for other drivers, attaching UBI devices has to be moved from late_initcall (which is too late for other drivers) to happen earlier. As an alternative to the existing kernel cmdline parameter the Device Tree property 'compatible = "linux,ubi";' inside an MTD partition can be used to have that MTD device attached as UBI device. MTD partitions which serve as UBI devices may have a "volumes" firmware subnode with volumes which may be compatible with "nvmem-cells".
In this way, other drivers (think: Ethernet, Wi-Fi) can resolve and acquire NVMEM bits using the usual device tree phandle, just this time the NVMEM content is read from a UBI volume.
[1]: https://patchwork.ozlabs.org/project/linux-mtd/list/?series=353177&state=%2A&archive=both
Daniel Golle (6):
mtd: ubi: block: don't return on error when removing
mtd: ubi: block: use notifier to create ubiblock from parameter
mtd: ubi: attach MTD partition from device-tree
mtd: ubi: introduce pre-removal notification for UBI volumes
mtd: ubi: populate ubi volume fwnode
mtd: ubi: provide NVMEM layer over UBI volumes
drivers/mtd/ubi/Kconfig | 12 +++ drivers/mtd/ubi/Makefile | 1 + drivers/mtd/ubi/block.c | 186 +++++++++++++++++++++++--------------- drivers/mtd/ubi/build.c | 160 ++++++++++++++++++++++++--------- drivers/mtd/ubi/cdev.c | 4 +- drivers/mtd/ubi/nvmem.c | 189 +++++++++++++++++++++++++++++++++++++++ drivers/mtd/ubi/ubi.h | 6 +- drivers/mtd/ubi/vmt.c | 36 ++++++++ include/linux/mtd/ubi.h | 2 + 9 files changed, 477 insertions(+), 119 deletions(-) create mode 100644 drivers/mtd/ubi/nvmem.c
Signature · 1 line
2.41.0
PATCH 1/6 mtd: ubi: block: don't return on error when removing
There is no point on returning the error from ubiblock_remove in case it is being called due to a volume removal event -- the volume is gone, we should destroy and remove the ubiblock device no matter what.
Introduce new boolean parameter 'force' to tell ubiblock_remove to go on even in case the ubiblock device is still busy. Use that new option when calling ubiblock_remove due to a UBI_VOLUME_REMOVED event.
--- drivers/mtd/ubi/block.c | 6 +++--- drivers/mtd/ubi/cdev.c | 2 +- drivers/mtd/ubi/ubi.h | 4 ++-- 3 files changed, 6 insertions(+), 6 deletions(-)
drivers/mtd/ubi/block.c +3 -3
@@ -456,7 +456,7 @@ static void ubiblock_cleanup(struct ubiblock *dev)idr_remove (&ubiblock_minor_idr, dev->gd->first_minor); } -int ubiblock_remove (struct ubi_volume_info *vi) +int ubiblock_remove (struct ubi_volume_info *vi,bool force) {struct ubiblock *dev;int ret;
@@ -470,7 +470,7 @@ int ubiblock_remove(struct ubi_volume_info *vi)/* Found a device, let's lock it so we can check if it's busy */ mutex_lock (&dev->dev_mutex); -if (dev->refcnt >0 ) { +if (dev->refcnt >0 && !force) { ret = -EBUSY ; goto out_unlock_dev; }
@@ -545,7 +545,7 @@ static int ubiblock_notify(struct notifier_block *nb,*/ break ;case UBI_VOLUME_REMOVED : -ubiblock_remove (&nt->vi); +ubiblock_remove (&nt->vi, true);break ;case UBI_VOLUME_RESIZED :ubiblock_resize (&nt->vi);
drivers/mtd/ubi/cdev.c +1 -1
@@ -572,7 +572,7 @@ static long vol_cdev_ioctl(struct file *file, unsigned int cmd,struct ubi_volume_info vi;ubi_get_volume_info (desc, &vi); - err =ubiblock_remove (&vi); + err =ubiblock_remove (&vi, false);break ; }
drivers/mtd/ubi/ubi.h +2 -2
@@ -979,7 +979,7 @@ static inline void ubi_fastmap_destroy_checkmap(struct ubi_volume *vol) {}int ubiblock_init (void );void ubiblock_exit (void );int ubiblock_create (struct ubi_volume_info *vi); -int ubiblock_remove (struct ubi_volume_info *vi); +int ubiblock_remove (struct ubi_volume_info *vi,bool force);#else static inline int ubiblock_init (void ) {return 0 ; }static inline void ubiblock_exit (void ) {}
@@ -987,7 +987,7 @@ static inline int ubiblock_create(struct ubi_volume_info *vi) {return -ENOSYS ; } -static inline int ubiblock_remove (struct ubi_volume_info *vi) +static inline int ubiblock_remove (struct ubi_volume_info *vi,bool force) {return -ENOSYS ; }
Signature · 1 line
2.41.0
PATCH 2/6 mtd: ubi: block: use notifier to create ubiblock from parameter
In reply to Daniel GolleUse UBI_VOLUME_ADDED notification to create ubiblock device specified on kernel cmdline or module parameter.
This makes thing more simple and has the advantage that ubiblock devices on volumes which are not present at the time the ubi module is probed will still be created.
--- drivers/mtd/ubi/block.c | 152 ++++++++++++++++++++++------------------ 1 file changed, 84 insertions(+), 68 deletions(-)
drivers/mtd/ubi/block.c +84 -68
@@ -33,6 +33,7 @@#include <linux/kernel.h> #include <linux/list.h> #include <linux/mutex.h> +#include <linux/namei.h> #include <linux/slab.h> #include <linux/mtd/ubi.h> #include <linux/blkdev.h>
@@ -65,10 +66,10 @@ struct ubiblock_pdu { };/* Numbers of elements set in the @ubiblock_param array */ -static int ubiblock_devs__initdata ; +static int ubiblock_devs;/* MTD devices specification parameters */ -static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES ]__initdata ; +static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES ];struct ubiblock {struct ubi_volume_desc *desc;
@@ -532,6 +533,85 @@ static int ubiblock_resize(struct ubi_volume_info *vi)return 0 ; } +static bool +match_volume_desc (struct ubi_volume_info *vi,const char *name,int ubi_num,int vol_id) +{ +int err, len; +struct path path; +struct kstat stat; + +if (ubi_num ==-1 ) { +/* No ubi num, name must be a vol device path */ + err =kern_path (name,LOOKUP_FOLLOW , &path); +if (err) +return false; + + err =vfs_getattr (&path, &stat,STATX_TYPE ,AT_STATX_SYNC_AS_STAT ); +path_put (&path); +if (err) +return false; + +if (!S_ISCHR (stat.mode)) +return false; + +if (vi->ubi_num !=ubi_major2num (MAJOR (stat.rdev))) +return false; + +if (vi->vol_id !=MINOR (stat.rdev) -1 ) +return false; + +return true; + } + +if (vol_id ==-1 ) { +if (vi->ubi_num != ubi_num) +return false; + + len =strnlen (name,UBI_VOL_NAME_MAX +1 ); +if (len <1 || vi->name_len != len) +return false; + +if (strcmp (name, vi->name)) +return false; + +return true; + } + +if (vi->ubi_num != ubi_num) +return false; + +if (vi->vol_id != vol_id) +return false; + +return true; +} + +static void +ubiblock_create_from_param (struct ubi_volume_info *vi) +{ +int i, ret =0 ; +struct ubiblock_param *p; + +/* +* Iterate over ubiblock cmdline parameters. If a parameter matches the +* newly added volume create the ubiblock device for it. +*/ +for (i =0 ; i < ubiblock_devs; i++) { + p = &ubiblock_param[i]; + +if (!match_volume_desc (vi, p->name, p->ubi_num, p->vol_id)) +continue ; + + ret =ubiblock_create (vi); +if (ret) { +pr_err ( +"UBI: block: can't add '%s' volume on ubi%d_%d, err=%d\n" , + vi->name, p->ubi_num, p->vol_id, ret); + } +break ; + } +} +static int ubiblock_notify (struct notifier_block *nb,unsigned long notification_type,void *ns_ptr) {
@@ -539,10 +619,7 @@ static int ubiblock_notify(struct notifier_block *nb,switch (notification_type) {case UBI_VOLUME_ADDED : -/* -* We want to enforce explicit block device creation for -* volumes, so when a volume is added we do nothing. -*/ +ubiblock_create_from_param (&nt->vi);break ;case UBI_VOLUME_REMOVED :ubiblock_remove (&nt->vi, true);
@@ -568,56 +645,6 @@ static struct notifier_block ubiblock_notifier = { .notifier_call = ubiblock_notify, }; -static struct ubi_volume_desc *__init -open_volume_desc (const char *name,int ubi_num,int vol_id) -{ -if (ubi_num ==-1 ) -/* No ubi num, name must be a vol device path */ -return ubi_open_volume_path (name,UBI_READONLY ); -else if (vol_id ==-1 ) -/* No vol_id, must be vol_name */ -return ubi_open_volume_nm (ubi_num, name,UBI_READONLY ); -else -return ubi_open_volume (ubi_num, vol_id,UBI_READONLY ); -} - -static void __init ubiblock_create_from_param (void ) -{ -int i, ret =0 ; -struct ubiblock_param *p; -struct ubi_volume_desc *desc; -struct ubi_volume_info vi; - -/* -* If there is an error creating one of the ubiblocks, continue on to -* create the following ubiblocks. This helps in a circumstance where -* the kernel command-line specifies multiple block devices and some -* may be broken, but we still want the working ones to come up. -*/ -for (i =0 ; i < ubiblock_devs; i++) { - p = &ubiblock_param[i]; - - desc =open_volume_desc (p->name, p->ubi_num, p->vol_id); -if (IS_ERR (desc)) { -pr_err ( -"UBI: block: can't open volume on ubi%d_%d, err=%ld\n" , - p->ubi_num, p->vol_id,PTR_ERR (desc)); -continue ; - } - -ubi_get_volume_info (desc, &vi); -ubi_close_volume (desc); - - ret =ubiblock_create (&vi); -if (ret) { -pr_err ( -"UBI: block: can't add '%s' volume on ubi%d_%d, err=%d\n" , - vi.name, p->ubi_num, p->vol_id, ret); -continue ; - } - } -} -static void ubiblock_remove_all (void ) {struct ubiblock *next;
@@ -643,18 +670,7 @@ int __init ubiblock_init(void)if (ubiblock_major <0 )return ubiblock_major; -/* -* Attach block devices from 'block=' module param. -* Even if one block device in the param list fails to come up, -* still allow the module to load and leave any others up. -*/ -ubiblock_create_from_param (); - -/* -* Block devices are only created upon user requests, so we ignore -* existing volumes. -*/ - ret =ubi_register_volume_notifier (&ubiblock_notifier,1 ); + ret =ubi_register_volume_notifier (&ubiblock_notifier,0 );if (ret) goto err_unreg;return 0 ;
Signature · 1 line
2.41.0
PATCH 3/6 mtd: ubi: attach MTD partition from device-tree
In reply to Daniel GolleSplit ubi_init() function into early function to be called by device_initcall() and keep cmdline attachment in late_initcall(). (when building ubi as module, both is still done in a single module_init() call)
Register MTD notifier and attach MTD devices which are marked as compatible with 'linux,ubi' in OF device-tree when being added, detach UBI device from MTD device when it is being removed.
For existing users this should not change anything besides automatic removal of (dead) UBI devices when their underlying MTD devices are already gone, e.g. in case of MTD driver module or (SPI) bus driver module being removed.
For new users this opens up the option to attach UBI using device-tree which then happens early and in parallel with other drivers being probed which slightly reduces the total boot time.
Attachment no longer happening late is also a requirement for other drivers to make use of UBI, e.g. drivers/nvmem/u-boot-env.c can now be extended to support U-Boot environment stored in UBI volumes.
--- drivers/mtd/ubi/block.c | 2 +- drivers/mtd/ubi/build.c | 153 +++++++++++++++++++++++++++++----------- drivers/mtd/ubi/cdev.c | 2 +- drivers/mtd/ubi/ubi.h | 2 +- 4 files changed, 115 insertions(+), 44 deletions(-)
drivers/mtd/ubi/block.c +1 -1
@@ -470,7 +470,7 @@ int ubiblock_remove(struct ubi_volume_info *vi, bool force) }/* Found a device, let's lock it so we can check if it's busy */ -mutex_lock (&dev->dev_mutex); +mutex_lock_nested (&dev->dev_mutex,SINGLE_DEPTH_NESTING );if (dev->refcnt >0 && !force) { ret = -EBUSY ; goto out_unlock_dev;
drivers/mtd/ubi/build.c +112 -41
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drivers/mtd/ubi/cdev.c +1 -1
@@ -1065,7 +1065,7 @@ static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd, }mutex_lock (&ubi_devices_mutex); - err =ubi_detach_mtd_dev (ubi_num,0 ); + err =ubi_detach_mtd_dev (ubi_num,0 , false);mutex_unlock (&ubi_devices_mutex);break ; }
drivers/mtd/ubi/ubi.h +1 -1
@@ -939,7 +939,7 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,int ubi_attach_mtd_dev (struct mtd_info *mtd,int ubi_num,int vid_hdr_offset,int max_beb_per1024,bool disable_fm); -int ubi_detach_mtd_dev (int ubi_num,int anyway); +int ubi_detach_mtd_dev (int ubi_num,int anyway,bool have_lock);struct ubi_device *ubi_get_device (int ubi_num);void ubi_put_device (struct ubi_device *ubi);struct ubi_device *ubi_get_by_major (int major);
Signature · 5 lines
2.41.0 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/
PATCH 4/6 mtd: ubi: introduce pre-removal notification for UBI volumes
In reply to Daniel GolleIntroduce a new notification type UBI_VOLUME_SHUTDOWN to inform users that a volume is just about to be removed.
This is needed because users (such as the NVMEM subsystem) expect that at the time their removal function is called, the parenting device is still available (for removal of sysfs nodes, for example, in case of NVMEM which otherwise WARNs on volume removal).
--- drivers/mtd/ubi/block.c | 26 ++++++++++++++++++++++++++ drivers/mtd/ubi/build.c | 7 ++++++- drivers/mtd/ubi/vmt.c | 5 +++++ include/linux/mtd/ubi.h | 2 ++ 4 files changed, 39 insertions(+), 1 deletion(-)
drivers/mtd/ubi/block.c +26 -0
@@ -533,6 +533,29 @@ static int ubiblock_resize(struct ubi_volume_info *vi)return 0 ; } +static int ubiblock_shutdown (struct ubi_volume_info *vi) +{ +struct ubiblock *dev; +struct gendisk *disk; +int ret =0 ; + +mutex_lock (&devices_mutex); + dev =find_dev_nolock (vi->ubi_num, vi->vol_id); +if (!dev) { + ret = -ENODEV ; + goto out_unlock; + } + disk = dev->gd; + +out_unlock: +mutex_unlock (&devices_mutex); + +if (!ret) +blk_mark_disk_dead (disk); + +return ret; +}; +static bool match_volume_desc (struct ubi_volume_info *vi,const char *name,int ubi_num,int vol_id) {
@@ -624,6 +647,9 @@ static int ubiblock_notify(struct notifier_block *nb,case UBI_VOLUME_REMOVED :ubiblock_remove (&nt->vi, true);break ; +case UBI_VOLUME_SHUTDOWN : +ubiblock_shutdown (&nt->vi); +break ;case UBI_VOLUME_RESIZED :ubiblock_resize (&nt->vi);break ;
drivers/mtd/ubi/build.c +6 -1
@@ -1088,7 +1088,6 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway, bool have_lock)return -EINVAL ;spin_lock (&ubi_devices_lock); -put_device (&ubi->dev); ubi->ref_count -=1 ;if (ubi->ref_count) {if (!anyway) {
@@ -1099,6 +1098,12 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway, bool have_lock)ubi_err (ubi,"%s reference count %d, destroy anyway" , ubi->ubi_name, ubi->ref_count); } +spin_unlock (&ubi_devices_lock); + +ubi_notify_all (ubi,UBI_VOLUME_SHUTDOWN ,NULL ); + +spin_lock (&ubi_devices_lock); +put_device (&ubi->dev); ubi_devices[ubi_num] =NULL ;spin_unlock (&ubi_devices_lock);
drivers/mtd/ubi/vmt.c +5 -0
@@ -352,6 +352,11 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl) err = -EBUSY ; goto out_unlock; } +spin_unlock (&ubi->volumes_lock); + +ubi_volume_notify (ubi, vol,UBI_VOLUME_SHUTDOWN ); + +spin_lock (&ubi->volumes_lock); ubi->volumes[vol_id] =NULL ;spin_unlock (&ubi->volumes_lock);
include/linux/mtd/ubi.h +2 -0
@@ -192,6 +192,7 @@ struct ubi_device_info {* or a volume was removed) * @UBI_VOLUME_RESIZED: a volume has been re-sized * @UBI_VOLUME_RENAMED: a volume has been re-named +* @UBI_VOLUME_SHUTDOWN: a volume is going to removed, shutdown users * @UBI_VOLUME_UPDATED: data has been written to a volume * * These constants define which type of event has happened when a volume
@@ -202,6 +203,7 @@ enum {UBI_VOLUME_REMOVED ,UBI_VOLUME_RESIZED ,UBI_VOLUME_RENAMED , +UBI_VOLUME_SHUTDOWN , UBI_VOLUME_UPDATED, };
Signature · 1 line
2.41.0
PATCH 5/6 mtd: ubi: populate ubi volume fwnode
In reply to Daniel GolleLook for the 'volumes' subnode of an MTD partition attached to a UBI device and attach matching child nodes to UBI volumes. This allows UBI volumes to be referenced in device tree, e.g. for use as NVMEM providers.
--- drivers/mtd/ubi/vmt.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+)
drivers/mtd/ubi/vmt.c +31 -0
@@ -124,6 +124,35 @@ static void vol_release(struct device *dev)kfree (vol); } +static struct fwnode_handle *find_volume_fwnode (struct ubi_volume *vol) +{ +struct fwnode_handle *fw_vols, *fw_vol; +const char *volname; +u32 reg; + + fw_vols =device_get_named_child_node (vol->dev.parent->parent,"volumes" ); +if (!fw_vols) +return NULL ; + +fwnode_for_each_child_node (fw_vols, fw_vol) { +if (!fwnode_property_read_string (fw_vol,"volname" , &volname) && +strncmp (volname, vol->name, vol->name_len)) +continue ; + +/* +* volume id (reg) in device tree greater than UBI_MAX_VOLUMES +* can be used to match by volname only +*/ +if (!fwnode_property_read_u32 (fw_vol,"reg" , ®) && + reg <UBI_MAX_VOLUMES && vol->vol_id != reg) +continue ; + +return fw_vol; + } + +return NULL ; +} +/** * ubi_create_volume - create volume. * @ubi: UBI device description object
@@ -223,6 +252,7 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req) vol->name_len = req->name_len;memcpy (vol->name, req->name, vol->name_len); vol->ubi = ubi; +device_set_node (&vol->dev,find_volume_fwnode (vol));/* * Finish all pending erases because there may be some LEBs belonging
@@ -597,6 +627,7 @@ int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol) vol->dev.class = &ubi_class; vol->dev.groups = volume_dev_groups;dev_set_name (&vol->dev,"%s_%d" , ubi->ubi_name, vol->vol_id); +device_set_node (&vol->dev,find_volume_fwnode (vol)); err =device_register (&vol->dev);if (err) {cdev_del (&vol->cdev);
Signature · 1 line
2.41.0
PATCH 6/6 mtd: ubi: provide NVMEM layer over UBI volumes
In reply to Daniel GolleIn an ideal world we would like UBI to be used where ever possible on a NAND chip. And with UBI support in ARM Trusted Firmware and U-Boot it is possible to achieve an (almost-)all-UBI flash layout. Hence the need for a way to also use UBI volumes to store board-level constants, such as MAC addresses and calibration data of wireless interfaces.
Add UBI volume NVMEM driver module exposing UBI volumes as NVMEM providers. Allow UBI devices to have a "volumes" firmware subnode with volumes which may be compatible with "nvmem-cells".
Access to UBI volumes via the NVMEM interface at this point is read-only, and it is slow, opening and closing the UBI volume for each access due to limitations of the NVMEM provider API.
--- drivers/mtd/ubi/Kconfig | 12 +++ drivers/mtd/ubi/Makefile | 1 + drivers/mtd/ubi/nvmem.c | 189 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 202 insertions(+) create mode 100644 drivers/mtd/ubi/nvmem.c
drivers/mtd/ubi/Kconfig +12 -0
@@ -104,4 +104,16 @@ config MTD_UBI_BLOCK If in doubt, say "N". +config MTD_UBI_NVMEM + tristate "UBI virtual NVMEM" + default n + depends on NVMEM + help + This option enabled an additional driver exposing UBI volumes as NVMEM + providers, intended for platforms where UBI is part of the firmware + specification and used to store also e.g. MAC addresses or board- + specific Wi-Fi calibration data. + + If in doubt, say "N". + endif # MTD_UBI
drivers/mtd/ubi/Makefile +1 -0
@@ -7,3 +7,4 @@ ubi-$(CONFIG_MTD_UBI_FASTMAP) += fastmap.o ubi-$(CONFIG_MTD_UBI_BLOCK) += block.o obj-$(CONFIG_MTD_UBI_GLUEBI) += gluebi.o +obj-$(CONFIG_MTD_UBI_NVMEM) += nvmem.o
drivers/mtd/ubi/nvmem.c new file +189 -0
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Signature · 1 line
2.41.0
Re: [PATCH 6/6] mtd: ubi: provide NVMEM layer over UBI volumes
Quoted 5 lines · Daniel Golle
drivers/mtd/ubi/Kconfig +0
-0
drivers/mtd/ubi/Kconfig config MTD_UBI_BLOCK · line 112
Quoted 9 lines
drivers/mtd/ubi/Kconfig +6
-0@@ -104,4 +104,16 @@ config MTD_UBI_BLOCK If in doubt, say "N". +config MTD_UBI_NVMEM + tristate "UBI virtual NVMEM" + default n + depends on NVMEM + help + This option enabled an additional driver exposing UBI volumes as NVMEM
enables
drivers/mtd/ubi/Kconfig config MTD_UBI_BLOCK · line 117
Quoted 5 lines
drivers/mtd/ubi/Kconfig +5
-0+ providers, intended for platforms where UBI is part of the firmware + specification and used to store also e.g. MAC addresses or board- + specific Wi-Fi calibration data. + + If in doubt, say "N".
and Kconfig help text should be indented with one tab + 2 spaces according to coding-style.rst.
Quoted 2 lines
drivers/mtd/ubi/Kconfig +1
-0+ endif # MTD_UBI
Signature · 1 line
~Randy