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-rw-r--r--include/linux/nvram.h133
1 files changed, 126 insertions, 7 deletions
diff --git a/include/linux/nvram.h b/include/linux/nvram.h
index 28bfb9ab94ca..d29d9c93a927 100644
--- a/include/linux/nvram.h
+++ b/include/linux/nvram.h
@@ -2,13 +2,132 @@
#ifndef _LINUX_NVRAM_H
#define _LINUX_NVRAM_H
+#include <linux/errno.h>
#include <uapi/linux/nvram.h>
-/* __foo is foo without grabbing the rtc_lock - get it yourself */
-extern unsigned char __nvram_read_byte(int i);
-extern unsigned char nvram_read_byte(int i);
-extern void __nvram_write_byte(unsigned char c, int i);
-extern void nvram_write_byte(unsigned char c, int i);
-extern int __nvram_check_checksum(void);
-extern int nvram_check_checksum(void);
+#ifdef CONFIG_PPC
+#include <asm/machdep.h>
+#endif
+
+/**
+ * struct nvram_ops - NVRAM functionality made available to drivers
+ * @read: validate checksum (if any) then load a range of bytes from NVRAM
+ * @write: store a range of bytes to NVRAM then update checksum (if any)
+ * @read_byte: load a single byte from NVRAM
+ * @write_byte: store a single byte to NVRAM
+ * @get_size: return the fixed number of bytes in the NVRAM
+ *
+ * Architectures which provide an nvram ops struct need not implement all
+ * of these methods. If the NVRAM hardware can be accessed only one byte
+ * at a time then it may be sufficient to provide .read_byte and .write_byte.
+ * If the NVRAM has a checksum (and it is to be checked) the .read and
+ * .write methods can be used to implement that efficiently.
+ *
+ * Portable drivers may use the wrapper functions defined here.
+ * The nvram_read() and nvram_write() functions call the .read and .write
+ * methods when available and fall back on the .read_byte and .write_byte
+ * methods otherwise.
+ */
+
+struct nvram_ops {
+ ssize_t (*get_size)(void);
+ unsigned char (*read_byte)(int);
+ void (*write_byte)(unsigned char, int);
+ ssize_t (*read)(char *, size_t, loff_t *);
+ ssize_t (*write)(char *, size_t, loff_t *);
+#if defined(CONFIG_X86) || defined(CONFIG_M68K)
+ long (*initialize)(void);
+ long (*set_checksum)(void);
+#endif
+};
+
+extern const struct nvram_ops arch_nvram_ops;
+
+static inline ssize_t nvram_get_size(void)
+{
+#ifdef CONFIG_PPC
+ if (ppc_md.nvram_size)
+ return ppc_md.nvram_size();
+#else
+ if (arch_nvram_ops.get_size)
+ return arch_nvram_ops.get_size();
+#endif
+ return -ENODEV;
+}
+
+static inline unsigned char nvram_read_byte(int addr)
+{
+#ifdef CONFIG_PPC
+ if (ppc_md.nvram_read_val)
+ return ppc_md.nvram_read_val(addr);
+#else
+ if (arch_nvram_ops.read_byte)
+ return arch_nvram_ops.read_byte(addr);
+#endif
+ return 0xFF;
+}
+
+static inline void nvram_write_byte(unsigned char val, int addr)
+{
+#ifdef CONFIG_PPC
+ if (ppc_md.nvram_write_val)
+ ppc_md.nvram_write_val(addr, val);
+#else
+ if (arch_nvram_ops.write_byte)
+ arch_nvram_ops.write_byte(val, addr);
+#endif
+}
+
+static inline ssize_t nvram_read_bytes(char *buf, size_t count, loff_t *ppos)
+{
+ ssize_t nvram_size = nvram_get_size();
+ loff_t i;
+ char *p = buf;
+
+ if (nvram_size < 0)
+ return nvram_size;
+ for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count)
+ *p = nvram_read_byte(i);
+ *ppos = i;
+ return p - buf;
+}
+
+static inline ssize_t nvram_write_bytes(char *buf, size_t count, loff_t *ppos)
+{
+ ssize_t nvram_size = nvram_get_size();
+ loff_t i;
+ char *p = buf;
+
+ if (nvram_size < 0)
+ return nvram_size;
+ for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count)
+ nvram_write_byte(*p, i);
+ *ppos = i;
+ return p - buf;
+}
+
+static inline ssize_t nvram_read(char *buf, size_t count, loff_t *ppos)
+{
+#ifdef CONFIG_PPC
+ if (ppc_md.nvram_read)
+ return ppc_md.nvram_read(buf, count, ppos);
+#else
+ if (arch_nvram_ops.read)
+ return arch_nvram_ops.read(buf, count, ppos);
+#endif
+ return nvram_read_bytes(buf, count, ppos);
+}
+
+static inline ssize_t nvram_write(char *buf, size_t count, loff_t *ppos)
+{
+#ifdef CONFIG_PPC
+ if (ppc_md.nvram_write)
+ return ppc_md.nvram_write(buf, count, ppos);
+#else
+ if (arch_nvram_ops.write)
+ return arch_nvram_ops.write(buf, count, ppos);
+#endif
+ return nvram_write_bytes(buf, count, ppos);
+}
+
#endif /* _LINUX_NVRAM_H */