Export redesign

this is an atempt to make the export of functions typesafe.
I replaced the jumptable void ** by a struct (jt_funcs) with function pointers.
The EXPORT_FUNC macro now has 3 fixed parameters and one
variadic parameter
The first is the name of the exported function,
the rest of the parameters are used to format a functionpointer
in the jumptable,

the EXPORT_FUNC macros are expanded three times,
1. to declare the members of the struct
2. to initialize the structmember pointers
3. to call the functions in stubs.c

Signed-off-by: Martin Dorwig <dorwig@tetronik.com>
Acked-by: Simon Glass <sjg@chromium.org>

Signed-off-by: Simon Glass <sjg@chromium.org>
(resending to the list since my tweaks are not quite trivial)

arch/blackfin/cpu/cpu.c

@@ -24,6 +24,7 @@
 
 #include "cpu.h"
 #include "initcode.h"
+#include "exports.h"
 
 ulong bfin_poweron_retx;
 DECLARE_GLOBAL_DATA_PTR;
@@ -121,7 +122,7 @@ static void display_global_data(void)
 	printf(" |-ram_size: %lx\n", gd->ram_size);
 	printf(" |-env_addr: %lx\n", gd->env_addr);
 	printf(" |-env_valid: %lx\n", gd->env_valid);
-	printf(" |-jt(%p): %p\n", gd->jt, *(gd->jt));
+	printf(" |-jt(%p): %p\n", gd->jt, gd->jt->get_version);
 	printf(" \\-bd: %p\n", gd->bd);
 	printf("   |-bi_boot_params: %lx\n", bd->bi_boot_params);
 	printf("   |-bi_memstart: %lx\n", bd->bi_memstart);

board/BuS/eb_cpux9k2/cpux9k2.c

@@ -98,7 +98,7 @@ int misc_init_r(void)
 				puts("Error: invalid MAC at EEPROM\n");
 		}
 	}
-	gd->jt[XF_do_reset] = (void *) do_reset;
+	gd->jt->do_reset = do_reset;
 
 #ifdef CONFIG_STATUS_LED
 	status_led_set(STATUS_LED_BOOT, STATUS_LED_BLINKING);

common/cmd_load.c

@@ -222,7 +222,7 @@ static int read_record(char *buf, ulong len)
 		}
 
 	    /* Check for the console hangup (if any different from serial) */
-	    if (gd->jt[XF_getc] != getc) {
+	    if (gd->jt->getc != getc) {
 		if (ctrlc()) {
 		    return (-1);
 		}

common/console.c

@@ -125,13 +125,13 @@ static int console_setfile(int file, struct stdio_dev * dev)
 		 */
 		switch (file) {
 		case stdin:
-			gd->jt[XF_getc] = getc;
-			gd->jt[XF_tstc] = tstc;
+			gd->jt->getc = getc;
+			gd->jt->tstc = tstc;
 			break;
 		case stdout:
-			gd->jt[XF_putc] = putc;
-			gd->jt[XF_puts] = puts;
-			gd->jt[XF_printf] = printf;
+			gd->jt->putc  = putc;
+			gd->jt->puts  = puts;
+			gd->jt->printf = printf;
 			break;
 		}
 		break;
@@ -758,11 +758,11 @@ int console_init_r(void)
 #endif
 
 	/* set default handlers at first */
-	gd->jt[XF_getc] = serial_getc;
-	gd->jt[XF_tstc] = serial_tstc;
-	gd->jt[XF_putc] = serial_putc;
-	gd->jt[XF_puts] = serial_puts;
-	gd->jt[XF_printf] = serial_printf;
+	gd->jt->getc  = serial_getc;
+	gd->jt->tstc  = serial_tstc;
+	gd->jt->putc  = serial_putc;
+	gd->jt->puts  = serial_puts;
+	gd->jt->printf = serial_printf;
 
 	/* stdin stdout and stderr are in environment */
 	/* scan for it */

common/exports.c

@@ -1,6 +1,7 @@
 #include <common.h>
 #include <exports.h>
 #include <spi.h>
+#include <i2c.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -13,34 +14,10 @@ unsigned long get_version(void)
 	return XF_VERSION;
 }
 
-/* Reuse _exports.h with a little trickery to avoid bitrot */
-#define EXPORT_FUNC(sym) gd->jt[XF_##sym] = (void *)sym;
-
-#if !defined(CONFIG_X86) && !defined(CONFIG_PPC)
-# define install_hdlr      dummy
-# define free_hdlr         dummy
-#else /* kludge for non-standard function naming */
-# define install_hdlr      irq_install_handler
-# define free_hdlr         irq_free_handler
-#endif
-#if !defined(CONFIG_CMD_I2C) || \
-	(defined(CONFIG_DM_I2C) && !defined(CONFIG_DM_I2C_COMPAT))
-# define i2c_write         dummy
-# define i2c_read          dummy
-#endif
-#if !defined(CONFIG_CMD_SPI) || defined(CONFIG_DM_SPI)
-# define spi_init          dummy
-# define spi_setup_slave   dummy
-# define spi_free_slave    dummy
-#endif
-#ifndef CONFIG_CMD_SPI
-# define spi_claim_bus     dummy
-# define spi_release_bus   dummy
-# define spi_xfer          dummy
-#endif
+#define EXPORT_FUNC(f, a, x, ...)  gd->jt->x = f;
 
 void jumptable_init(void)
 {
-	gd->jt = malloc(XF_MAX * sizeof(void *));
+	gd->jt = malloc(sizeof(struct jt_funcs));
 #include <_exports.h>
 }

doc/README.standalone

@@ -5,18 +5,18 @@ Design Notes on Exporting U-Boot Functions to Standalone Applications:
    table is allocated and initialized in the jumptable_init() routine
    (common/exports.c). Other routines may also modify the jump table,
    however. The jump table can be accessed as the 'jt' field of the
-   'global_data' structure. The slot numbers for the jump table are
+   'global_data' structure. The struct members for the jump table are
    defined in the <include/exports.h> header. E.g., to substitute the
    malloc() and free() functions that will be available to standalone
    applications, one should do the following:
 
 	DECLARE_GLOBAL_DATA_PTR;
 
-	gd->jt[XF_malloc]	= my_malloc;
-	gd->jt[XF_free]		= my_free;
+	gd->jt->malloc	= my_malloc;
+	gd->jt->free = my_free;
 
-   Note that the pointers to the functions all have 'void *' type and
-   thus the compiler cannot perform type checks on these assignments.
+   Note that the pointers to the functions are real function pointers
+   so the compiler can perform type checks on these assignments.
 
 2. The pointer to the jump table is passed to the application in a
    machine-dependent way. PowerPC, ARM, MIPS, Blackfin and Nios II
@@ -65,27 +65,46 @@ Design Notes on Exporting U-Boot Functions to Standalone Applications:
    => tftp 0x40000 hello_world.bin
    => go 0x40004
 
-5. To export some additional function foobar(), the following steps
+5. To export some additional function long foobar(int i,char c), the following steps
    should be undertaken:
 
    - Append the following line at the end of the include/_exports.h
      file:
 
-	EXPORT_FUNC(foobar)
+	EXPORT_FUNC(foobar, long, foobar, int, char)
+
+	Parameters to EXPORT_FUNC:
+	 - the first parameter is the function that is exported (default implementation)
+	 - the second parameter is the return value type
+	 - the third  parameter is the name of the member in struct jt_funcs
+	   this is also the name that the standalone application will used.
+	   the rest of the parameters are the function arguments
 
    - Add the prototype for this function to the include/exports.h
      file:
 
-	void foobar(void);
+	long foobar(int i, char c);
+
+	Initialization with the default implementation is done in jumptable_init()
+
+	You can override the default implementation using:
 
-   - Add the initialization of the jump table slot wherever
-     appropriate (most likely, to the jumptable_init() function):
+	gd->jt->foobar = another_foobar;
 
-	gd->jt[XF_foobar] = foobar;
+	The signature of another_foobar must then match the declaration of foobar.
 
    - Increase the XF_VERSION value by one in the include/exports.h
      file
 
+   - If you want to export a function which depends on a CONFIG_XXX
+	use 2 lines like this:
+	#ifdef CONFIG_FOOBAR
+		EXPORT_FUNC(foobar, long, foobar, int, char)
+	#else
+		EXPORT_FUNC(dummy, void, foobar, void)
+	#endif
+
+
 6. The code for exporting the U-Boot functions to applications is
    mostly machine-independent. The only places written in assembly
    language are stub functions that perform the jump through the jump