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![Kevin Hilman](/assets/img/avatar_default.png)
Add an interface by which other kernel code can read/write persistent memory such as I2C or SPI EEPROMs, or devices which provide NVRAM. Use cases include storage of board-specific configuration data like Ethernet addresses and sensor calibrations. Original idea, review and improvement suggestions by David Brownell. Acked-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
113 lines
3.3 KiB
C
113 lines
3.3 KiB
C
/*
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* include/linux/memory.h - generic memory definition
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*
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* This is mainly for topological representation. We define the
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* basic "struct memory_block" here, which can be embedded in per-arch
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* definitions or NUMA information.
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*
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* Basic handling of the devices is done in drivers/base/memory.c
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* and system devices are handled in drivers/base/sys.c.
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*
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* Memory block are exported via sysfs in the class/memory/devices/
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* directory.
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*
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*/
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#ifndef _LINUX_MEMORY_H_
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#define _LINUX_MEMORY_H_
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#include <linux/sysdev.h>
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#include <linux/node.h>
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#include <linux/compiler.h>
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#include <linux/mutex.h>
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struct memory_block {
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unsigned long phys_index;
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unsigned long state;
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/*
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* This serializes all state change requests. It isn't
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* held during creation because the control files are
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* created long after the critical areas during
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* initialization.
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*/
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struct mutex state_mutex;
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int phys_device; /* to which fru does this belong? */
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void *hw; /* optional pointer to fw/hw data */
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int (*phys_callback)(struct memory_block *);
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struct sys_device sysdev;
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};
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/* These states are exposed to userspace as text strings in sysfs */
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#define MEM_ONLINE (1<<0) /* exposed to userspace */
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#define MEM_GOING_OFFLINE (1<<1) /* exposed to userspace */
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#define MEM_OFFLINE (1<<2) /* exposed to userspace */
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#define MEM_GOING_ONLINE (1<<3)
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#define MEM_CANCEL_ONLINE (1<<4)
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#define MEM_CANCEL_OFFLINE (1<<5)
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struct memory_notify {
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unsigned long start_pfn;
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unsigned long nr_pages;
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int status_change_nid;
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};
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struct notifier_block;
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struct mem_section;
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/*
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* Priorities for the hotplug memory callback routines (stored in decreasing
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* order in the callback chain)
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*/
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#define SLAB_CALLBACK_PRI 1
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#define IPC_CALLBACK_PRI 10
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#ifndef CONFIG_MEMORY_HOTPLUG_SPARSE
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static inline int memory_dev_init(void)
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{
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return 0;
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}
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static inline int register_memory_notifier(struct notifier_block *nb)
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{
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return 0;
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}
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static inline void unregister_memory_notifier(struct notifier_block *nb)
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{
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}
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static inline int memory_notify(unsigned long val, void *v)
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{
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return 0;
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}
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#else
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extern int register_memory_notifier(struct notifier_block *nb);
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extern void unregister_memory_notifier(struct notifier_block *nb);
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extern int register_new_memory(int, struct mem_section *);
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extern int unregister_memory_section(struct mem_section *);
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extern int memory_dev_init(void);
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extern int remove_memory_block(unsigned long, struct mem_section *, int);
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extern int memory_notify(unsigned long val, void *v);
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extern struct memory_block *find_memory_block(struct mem_section *);
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#define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
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enum mem_add_context { BOOT, HOTPLUG };
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#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
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#ifdef CONFIG_MEMORY_HOTPLUG
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#define hotplug_memory_notifier(fn, pri) { \
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static __meminitdata struct notifier_block fn##_mem_nb =\
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{ .notifier_call = fn, .priority = pri }; \
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register_memory_notifier(&fn##_mem_nb); \
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}
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#else
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#define hotplug_memory_notifier(fn, pri) do { } while (0)
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#endif
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/*
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* 'struct memory_accessor' is a generic interface to provide
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* in-kernel access to persistent memory such as i2c or SPI EEPROMs
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*/
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struct memory_accessor {
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ssize_t (*read)(struct memory_accessor *, char *buf, off_t offset,
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size_t count);
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ssize_t (*write)(struct memory_accessor *, const char *buf,
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off_t offset, size_t count);
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};
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#endif /* _LINUX_MEMORY_H_ */
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