Add documentation to flash.h:

- provides low-level information about each flash API interface,
- gives driver authors some documentation about the driver interface,
- updated extensively from the original patch provided by Duane Ellis.


git-svn-id: svn://svn.berlios.de/openocd/trunk@1942 b42882b7-edfa-0310-969c-e2dbd0fdcd60

src/flash/flash.h

@@ -33,65 +33,298 @@ struct image_s;
 
 #define FLASH_MAX_ERROR_STR	(128)
 
+/**
+ * Describes the geometry and status of a single flash sector
+ * within a flash bank.  A single bank typically consists of multiple
+ * sectors, each of which can be erased and protected independently.
+ */
 typedef struct flash_sector_s
 {
+	/// Bus offset from start of the flash chip (in bytes).
 	u32 offset;
+	/// Number of bytes in this flash sector.
 	u32 size;
+	/**
+	 * Indication of erasure status: 0=not erased, 1=erased,
+	 * other=unknown.  Set by @c flash_driver_s::erase_check.
+	 */
 	int is_erased;
+	/**
+	 * Indication of protection status: 0=unprotected/unlocked,
+	 * 1=protected/locked, other=unknown.  Set by
+	 * @c flash_driver_s::protect_check.
+	 */
 	int is_protected;
 } flash_sector_t;
 
 struct flash_bank_s;
 
+/**
+ * @brief Provides the implementation-independent structure that defines
+ * all of the callbacks required by OpenOCD flash drivers.
+ *
+ * Driver authors must implement the routines defined here, providing an
+ * instance with the fields filled out.  After that, the instance must
+ * be registered in flash.c, so it can be used by the driver lookup system.
+ *
+ * Specifically, the user can issue the command: @par
+ * @code
+ * flash bank DRIVERNAME ...parameters...
+ * @endcode
+ *
+ * OpenOCD will search for the driver with a @c flash_driver_s::name
+ * that matches @c DRIVERNAME.
+ *
+ * The flash subsystem calls some of the other drivers routines a using
+ * corresponding static <code>flash_driver_<i>callback</i>()</code>
+ * routine in flash.c.
+ */
 typedef struct flash_driver_s
 {
+	/** 
+	 * Gives a human-readable name of this flash driver,
+	 * This field is used to select and initialize the driver.
+	 */
 	char *name;
+
+	/** 
+	 * Registers driver-specific commands.  When called (during the
+	 * "flash bank" command), the driver may register addition
+	 * commands to support new flash chip functions.
+	 *
+	 * @returns ERROR_OK if successful; otherwise, an error code.
+	 */
 	int (*register_commands)(struct command_context_s *cmd_ctx);
+
+	/** 
+	 * Finish the "flash bank" command for @a bank.  The
+	 * @a bank parameter will have been filled in by the core flash
+	 * layer when this routine is called, and the driver can store
+	 * additional information in its flash_bank_t::driver_priv field.
+	 * 
+	 * @param cmd_ctx - the command context
+	 * @param cmd     - the command, in this case 'flash'
+	 * @param args    - parameters, see below
+	 * @param argc    - number of parameters on command line
+	 * @param bank    - new filled in flash bank.
+	 *
+	 * The args are: @par
+	 * @code
+	 * args[0] = bank
+	 * args[1] = drivername {name above}
+	 * args[2] = baseaddress 
+	 * args[3] = lengthbytes
+	 * args[4] = chip_width_in bytes
+	 * args[5] = bus_width_bytes
+	 * args[6] = driver-specific parameters
+	 * @endcode
+	 *
+	 * For example, args[4] = 16 bit flash, args[5] = 32bit bus.
+	 *
+	 * If extra arguments are provided (@a argc > 6), they will
+	 * start in @a args[6].  These can be used to implement
+	 * driver-specific extensions.
+	 *
+	 * @returns ERROR_OK if successful; otherwise, an error code.
+	 */
 	int (*flash_bank_command)(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc, struct flash_bank_s *bank);
 
-	/* use flash_driver_erase() wrapper to invoke */
+	/** 
+	 * Bank/sector erase routine (target-specific).  When
+	 * called, the flash driver should erase the specified sectors
+	 * using whatever means are at its disposal.
+	 *
+	 * @param bank The bank of flash to be erased.
+	 * @param first The number of the first sector to erase, typically 0.
+	 * @param last The number of the last sector to erase, typically N-1.
+	 * @returns ERROR_OK if successful; otherwise, an error code.
+	 */
 	int (*erase)(struct flash_bank_s *bank, int first, int last);
 
-	/* use flash_driver_protect() wrapper to invoke */
+	/** 
+	 * Bank/sector protection routine (target-specific).
+	 * When called, the driver should disable 'flash write' bits (or
+	 * enable 'erase protection' bits) for the given @a bank and @a
+	 * sectors.
+	 *
+	 * @param bank The bank to protect or unprotect.
+	 * @param set If non-zero, enable protection; if 0, disable it.
+	 * @param first The first sector to (un)protect, typicaly 0.
+	 * @param last The last sector to (un)project, typically N-1.
+	 * @returns ERROR_OK if successful; otherwise, an error code.
+	 */
 	int (*protect)(struct flash_bank_s *bank, int set, int first, int last);
 
-	/* use the flash_driver_write() wrapper to invoke. */
+	/** 
+	 * Program data into the flash.  Note CPU address will be
+	 * "bank->base + offset", while the physical address is
+	 * dependent upon current target MMU mappings.
+	 *
+	 * @param bank The bank to program
+	 * @param buffer The data bytes to write.
+	 * @param offset The offset into the chip to program.
+	 * @param count The number of bytes to write.
+	 * @returns ERROR_OK if successful; otherwise, an error code.
+	 */
 	int (*write)(struct flash_bank_s *bank, u8 *buffer, u32 offset, u32 count);
 
+	/** 
+	 * Probe to determine what kind of flash is present.
+	 * This is invoked by the "probe" script command.
+	 *
+	 * @param bank The bank to probe
+	 * @returns ERROR_OK if successful; otherwise, an error code.
+	 */
 	int (*probe)(struct flash_bank_s *bank);
+	
+	/** 
+	 * Check the erasure status of a flash bank.
+	 * When called, the driver routine must perform the required
+	 * checks and then set the @c flash_sector_s::is_erased field
+	 * for each of the flash banks's sectors.
+	 *
+	 * @param bank The bank to check
+	 * @returns ERROR_OK if successful; otherwise, an error code.
+	 */
 	int (*erase_check)(struct flash_bank_s *bank);
+
+	/**
+	 * Determine if the specific bank is "protected" or not.
+	 * When called, the driver routine must must perform the
+	 * required protection check(s) and then set the @c
+	 * flash_sector_s::is_protected field for each of the flash
+	 * bank's sectors.
+	 *
+	 * @param bank - the bank to check
+	 * @returns ERROR_OK if successful; otherwise, an error code.
+	 */
 	int (*protect_check)(struct flash_bank_s *bank);
+
+	/**
+	 * Display human-readable information about the flash
+	 * bank into the given buffer.  Drivers must be careful to avoid
+	 * overflowing the buffer.
+	 *
+	 * @param bank - the bank to get info about
+	 * @param char - where to put the text for the human to read
+	 * @param buf_size - the size of the human buffer.
+	 * @returns ERROR_OK if successful; otherwise, an error code.
+	 */ 
 	int (*info)(struct flash_bank_s *bank, char *buf, int buf_size);
+
+	/**
+	 * A more gentle flavor of filash_driver_s::probe, performing
+	 * setup with less noise.  Generally, driver routines should test
+	 * to seee if the bank has already been probed; if it has, the
+	 * driver probably should not perform its probe a second time.
+	 *
+	 * This callback is often called from the inside of other
+	 * routines (e.g. GDB flash downloads) to autoprobe the flash as
+	 * it is programing the flash.
+	 *
+	 * @param bank - the bank to probe
+	 * @returns ERROR_OK if successful; otherwise, an error code.
+	 */
 	int (*auto_probe)(struct flash_bank_s *bank);
 } flash_driver_t;
 
+/** 
+ * Provides details of a flash bank, available either on-chip or through
+ * a major interface.
+ *
+ * This structure will be passed as a parameter to the callbacks in the
+ * flash_driver_s structure, some of which may modify the contents of
+ * this structure of the area of flash that it defines.  Driver writers
+ * may use the @c driver_priv member to store additional data on a
+ * per-bank basis, if required.
+ */
 typedef struct flash_bank_s
 {
-	struct target_s *target;
-	flash_driver_t *driver;
-	void *driver_priv;
-	int bank_number;
-	u32 base;
-	u32 size;
-	int chip_width;
-	int bus_width;
+	struct target_s *target; /**< Target to which this bank belongs. */
+
+	flash_driver_t *driver; /**< Driver for this bank. */
+	void *driver_priv; /**< Private driver storage pointer */
+
+	int bank_number; /**< The 'bank' (or chip number) of this instance. */
+	u32 base; /**< The base address of this bank */
+	u32 size; /**< The size of this chip bank, in bytes */
+
+	int chip_width; /**< Width of the chip in bytes (1,2,4 bytes) */
+	int bus_width; /**< Maximum bus width, in bytes (1,2,4 bytes) */
+
+	/**
+	 * The number of sectors on this chip.  This value will
+	 * be set intially to 0, and the flash driver must set this to
+	 * some non-zero value during "probe()" or "auto_probe()".
+	 */
 	int num_sectors;
+	/// Array of sectors, allocated and initilized by the flash driver
 	flash_sector_t *sectors;
-	struct flash_bank_s *next;
+
+	struct flash_bank_s *next; /**< The next flash bank on this chip */
 } flash_bank_t;
 
+/// Registers the 'flash' subsystem commands
 extern int flash_register_commands(struct command_context_s *cmd_ctx);
+/// Initializes the 'flash' subsystem drivers
 extern int flash_init_drivers(struct command_context_s *cmd_ctx);
 
+/**
+ * Erases @a length bytes in the @a target flash, starting at @a addr.
+ * @returns ERROR_OK if successful; otherwise, an error code.
+ */
 extern int flash_erase_address_range(struct target_s *target, u32 addr, u32 length);
+/**
+ * Writes @a image into the @a target flash.  The @a written parameter
+ * will contain the 
+ * @param target The target with the flash to be programmed.
+ * @param image The image that will be programmed to flash.
+ * @param written On return, contains the number of bytes written.
+ * @param erase If non-zero, indicates the flash driver should first
+ * erase the corresponding banks or sectors before programming.
+ * @returns ERROR_OK if successful; otherwise, an error code.
+ */
 extern int flash_write(struct target_s *target, struct image_s *image, u32 *written, int erase);
+/**
+ * Forces targets to re-examine their erase/protection state.
+ * This routine must be called when the system may modify the status.
+ */
 extern void flash_set_dirty(void);
+/// @returns The number of flash banks currently defined.
 extern int flash_get_bank_count(void);
+/**
+ * Provides default erased-bank check handling. Checks to see if
+ * the flash driver knows they are erased; if things look uncertain,
+ * this routine will call default_flash_mem_blank_check() to confirm.
+ * @returns ERROR_OK if successful; otherwise, an error code.
+ */
 extern int default_flash_blank_check(struct flash_bank_s *bank);
+/**
+ * Provides a default blank flash memory check.  Ensures the contents
+ * of the given bank have truly been erased.
+ * @param bank The flash bank.
+ * @returns ERROR_OK if successful; otherwise, an error code.
+ */
 extern int default_flash_mem_blank_check(struct flash_bank_s *bank);
 
+/**
+ * Returns a flash bank by the specified flash_bank_s bank_number, @a num.
+ * @param num The flash bank number.
+ * @returns A flash_bank_t for flash bank @a num, or NULL
+ */
 extern flash_bank_t *get_flash_bank_by_num(int num);
+/**
+ * Returns the flash bank like get_flash_bank_by_num(), without probing.
+ * @param num The flash bank number.
+ * @returns A flash_bank_t for flash bank @a num, or NULL.
+ */
 extern flash_bank_t *get_flash_bank_by_num_noprobe(int num);
+/**
+ * Returns the flash bank located at a specified address.
+ * @param target The target, presumed to contain one or more banks.
+ * @param addr An address that is within the range of the bank.
+ * @returns The flash_bank_t located at @a addr, or NULL.
+ */
 extern flash_bank_t *get_flash_bank_by_addr(struct target_s *target, u32 addr);
 
 #define ERROR_FLASH_BANK_INVALID			(-900)