fw_cfg: move internal function call docs to header file

Move documentation for fw_cfg functions internal to qemufrom
docs/specs/fw_cfg.txt to the fw_cfg.h header file, next to
their prototype declarations, formatted as doc-comments.

NOTE: Documentation for fw_cfg_add_callback() is completely
dropped by this patch, as that function has been eliminated
by commit 023e3148.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Marc Marí <markmb@redhat.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1446733972-1602-2-git-send-email-somlo@cmu.edu
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

docs/specs/fw_cfg.txt

@@ -192,90 +192,7 @@ To check the result, read the "control" field:
                             today due to implementation not being async,
                             but may in the future).
 
-= Host-side API =
+= Externally Provided Items =
-
-The following functions are available to the QEMU programmer for adding
-data to a fw_cfg device during guest initialization (see fw_cfg.h for
-each function's complete prototype):
-
-== fw_cfg_add_bytes() ==
-
-Given a selector key value, starting pointer, and size, create an item
-as a raw "blob" of the given size, available by selecting the given key.
-The data referenced by the starting pointer is only linked, NOT copied,
-into the data structure of the fw_cfg device.
-
-== fw_cfg_add_string() ==
-
-Instead of a starting pointer and size, this function accepts a pointer
-to a NUL-terminated ascii string, and inserts a newly allocated copy of
-the string (including the NUL terminator) into the fw_cfg device data
-structure.
-
-== fw_cfg_add_iXX() ==
-
-Insert an XX-bit item, where XX may be 16, 32, or 64. These functions
-will convert a 16-, 32-, or 64-bit integer to little-endian, then add
-a dynamically allocated copy of the appropriately sized item to fw_cfg
-under the given selector key value.
-
-== fw_cfg_modify_iXX() ==
-
-Modify the value of an XX-bit item (where XX may be 16, 32, or 64).
-Similarly to the corresponding fw_cfg_add_iXX() function set, convert
-a 16-, 32-, or 64-bit integer to little endian, create a dynamically
-allocated copy of the required size, and replace the existing item at
-the given selector key value with the newly allocated one. The previous
-item, assumed to have been allocated during an earlier call to
-fw_cfg_add_iXX() or fw_cfg_modify_iXX() (of the same width XX), is freed
-before the function returns.
-
-== fw_cfg_add_file() ==
-
-Given a filename (i.e., fw_cfg item name), starting pointer, and size,
-create an item as a raw "blob" of the given size. Unlike fw_cfg_add_bytes()
-above, the next available selector key (above 0x0020, FW_CFG_FILE_FIRST)
-will be used, and a new entry will be added to the file directory structure
-(at key 0x0019), containing the item name, blob size, and automatically
-assigned selector key value. The data referenced by the starting pointer
-is only linked, NOT copied, into the fw_cfg data structure.
-
-== fw_cfg_add_file_callback() ==
-
-Like fw_cfg_add_file(), but additionally sets pointers to a callback
-function (and opaque argument), which will be executed host-side by
-QEMU each time a byte is read by the guest from this particular item.
-
-NOTE: The callback function is given the opaque argument set by
-fw_cfg_add_file_callback(), but also the current data offset,
-allowing it the option of only acting upon specific offset values
-(e.g., 0, before the first data byte of the selected item is
-returned to the guest).
-
-== fw_cfg_modify_file() ==
-
-Given a filename (i.e., fw_cfg item name), starting pointer, and size,
-completely replace the configuration item referenced by the given item
-name with the new given blob. If an existing blob is found, its
-callback information is removed, and a pointer to the old data is
-returned to allow the caller to free it, helping avoid memory leaks.
-If a configuration item does not already exist under the given item
-name, a new item will be created as with fw_cfg_add_file(), and NULL
-is returned to the caller. In any case, the data referenced by the
-starting pointer is only linked, NOT copied, into the fw_cfg data
-structure.
-
-== fw_cfg_add_callback() ==
-
-Like fw_cfg_add_bytes(), but additionally sets pointers to a callback
-function (and opaque argument), which will be executed host-side by
-QEMU each time a guest-side write operation to this particular item
-completes fully overwriting the item's data.
-
-NOTE: This function is deprecated, and will be completely removed
-starting with QEMU v2.4.
-
-== Externally Provided Items ==
 
 As of v2.4, "file" fw_cfg items (i.e., items with selector keys above
 FW_CFG_FILE_FIRST, and with a corresponding entry in the fw_cfg file

include/hw/nvram/fw_cfg.h

@@ -73,19 +73,148 @@ typedef struct FWCfgDmaAccess {
 typedef void (*FWCfgCallback)(void *opaque, uint8_t *data);
 typedef void (*FWCfgReadCallback)(void *opaque, uint32_t offset);
 
+/**
+ * fw_cfg_add_bytes:
+ * @s: fw_cfg device being modified
+ * @key: selector key value for new fw_cfg item
+ * @data: pointer to start of item data
+ * @len: size of item data
+ *
+ * Add a new fw_cfg item, available by selecting the given key, as a raw
+ * "blob" of the given size. The data referenced by the starting pointer
+ * is only linked, NOT copied, into the data structure of the fw_cfg device.
+ */
 void fw_cfg_add_bytes(FWCfgState *s, uint16_t key, void *data, size_t len);
+
+/**
+ * fw_cfg_add_string:
+ * @s: fw_cfg device being modified
+ * @key: selector key value for new fw_cfg item
+ * @value: NUL-terminated ascii string
+ *
+ * Add a new fw_cfg item, available by selecting the given key. The item
+ * data will consist of a dynamically allocated copy of the provided string,
+ * including its NUL terminator.
+ */
 void fw_cfg_add_string(FWCfgState *s, uint16_t key, const char *value);
+
+/**
+ * fw_cfg_add_i16:
+ * @s: fw_cfg device being modified
+ * @key: selector key value for new fw_cfg item
+ * @value: 16-bit integer
+ *
+ * Add a new fw_cfg item, available by selecting the given key. The item
+ * data will consist of a dynamically allocated copy of the given 16-bit
+ * value, converted to little-endian representation.
+ */
 void fw_cfg_add_i16(FWCfgState *s, uint16_t key, uint16_t value);
+
+/**
+ * fw_cfg_modify_i16:
+ * @s: fw_cfg device being modified
+ * @key: selector key value for new fw_cfg item
+ * @value: 16-bit integer
+ *
+ * Replace the fw_cfg item available by selecting the given key. The new
+ * data will consist of a dynamically allocated copy of the given 16-bit
+ * value, converted to little-endian representation. The data being replaced,
+ * assumed to have been dynamically allocated during an earlier call to
+ * either fw_cfg_add_i16() or fw_cfg_modify_i16(), is freed before returning.
+ */
 void fw_cfg_modify_i16(FWCfgState *s, uint16_t key, uint16_t value);
+
+/**
+ * fw_cfg_add_i32:
+ * @s: fw_cfg device being modified
+ * @key: selector key value for new fw_cfg item
+ * @value: 32-bit integer
+ *
+ * Add a new fw_cfg item, available by selecting the given key. The item
+ * data will consist of a dynamically allocated copy of the given 32-bit
+ * value, converted to little-endian representation.
+ */
 void fw_cfg_add_i32(FWCfgState *s, uint16_t key, uint32_t value);
+
+/**
+ * fw_cfg_add_i64:
+ * @s: fw_cfg device being modified
+ * @key: selector key value for new fw_cfg item
+ * @value: 64-bit integer
+ *
+ * Add a new fw_cfg item, available by selecting the given key. The item
+ * data will consist of a dynamically allocated copy of the given 64-bit
+ * value, converted to little-endian representation.
+ */
 void fw_cfg_add_i64(FWCfgState *s, uint16_t key, uint64_t value);
+
+/**
+ * fw_cfg_add_file:
+ * @s: fw_cfg device being modified
+ * @filename: name of new fw_cfg file item
+ * @data: pointer to start of item data
+ * @len: size of item data
+ *
+ * Add a new NAMED fw_cfg item as a raw "blob" of the given size. The data
+ * referenced by the starting pointer is only linked, NOT copied, into the
+ * data structure of the fw_cfg device.
+ * The next available (unused) selector key starting at FW_CFG_FILE_FIRST
+ * will be used; also, a new entry will be added to the file directory
+ * structure residing at key value FW_CFG_FILE_DIR, containing the item name,
+ * data size, and assigned selector key value.
+ */
 void fw_cfg_add_file(FWCfgState *s, const char *filename, void *data,
                      size_t len);
+
+/**
+ * fw_cfg_add_file_callback:
+ * @s: fw_cfg device being modified
+ * @filename: name of new fw_cfg file item
+ * @callback: callback function
+ * @callback_opaque: argument to be passed into callback function
+ * @data: pointer to start of item data
+ * @len: size of item data
+ *
+ * Add a new NAMED fw_cfg item as a raw "blob" of the given size. The data
+ * referenced by the starting pointer is only linked, NOT copied, into the
+ * data structure of the fw_cfg device.
+ * The next available (unused) selector key starting at FW_CFG_FILE_FIRST
+ * will be used; also, a new entry will be added to the file directory
+ * structure residing at key value FW_CFG_FILE_DIR, containing the item name,
+ * data size, and assigned selector key value.
+ * Additionally, set a callback function (and argument) to be called each
+ * time a byte is read by the guest from this particular item, or, in the
+ * case of DMA, each time a read or skip request overlaps with the valid
+ * offset range of the item.
+ * NOTE: In addition to the opaque argument set here, the callback function
+ * takes the current data offset as an additional argument, allowing it the
+ * option of only acting upon specific offset values (e.g., 0, before the
+ * first data byte of the selected item is returned to the guest).
+ */
 void fw_cfg_add_file_callback(FWCfgState *s, const char *filename,
                               FWCfgReadCallback callback, void *callback_opaque,
                               void *data, size_t len);
+
+/**
+ * fw_cfg_modify_file:
+ * @s: fw_cfg device being modified
+ * @filename: name of new fw_cfg file item
+ * @data: pointer to start of item data
+ * @len: size of item data
+ *
+ * Replace a NAMED fw_cfg item. If an existing item is found, its callback
+ * information will be cleared, and a pointer to its data will be returned
+ * to the caller, so that it may be freed if necessary. If an existing item
+ * is not found, this call defaults to fw_cfg_add_file(), and NULL is
+ * returned to the caller.
+ * In either case, the new item data is only linked, NOT copied, into the
+ * data structure of the fw_cfg device.
+ *
+ * Returns: pointer to old item's data, or NULL if old item does not exist.
+ */
 void *fw_cfg_modify_file(FWCfgState *s, const char *filename, void *data,
                          size_t len);
+
 FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t dma_iobase,
                                 AddressSpace *dma_as);
 FWCfgState *fw_cfg_init_io(uint32_t iobase);