p7utils/src/p7os/cake.exe/libgint/src/core/gint.c

//---
//
//	gint core module: interrupt handler
//
//	Central point of the library. Controls the interrupt handler and
//	defines a few functions to configure callbacks for some interrupts.
//
//---

#include <internals/gint.h>
#include <gint.h>
#include <mpu.h>
#include <stddef.h>

static unsigned int
	new_vbr,
	sys_vbr;

static void (*default_handler)(int event_code) = NULL;



//---
//	Local functions.
//---

/*
	gint_setup()
	Configures interrupt priorities and some parameters to allow gint to
	take control of the interrupt flow.
*/
static void gint_setup(void)
{
	if(isSH3())
		gint_setup_7705();
	else
		gint_setup_7305();
}

/*
	gint_stop()
	Un-configures the interrupt flow to give back the interrupt control to
	the system.
*/
static void gint_stop(void)
{
	if(isSH3())
		gint_stop_7705();
	else
		gint_stop_7305();
}



//---
//	Public API.
//---

/*
	gint_systemVBR()
	Returns the vbr address used by the system (saved when execution
	starts).
*/
inline unsigned int gint_systemVBR(void)
{
	return sys_vbr;
}

/*
	gint_setDefaultHandler()
	In case gint receives an interrupt it doesn't recognize, it can fall
	back to a user-provided interrupt handler. Set it to NULL to disable
	this feature.
	Be aware that the event code passed to the default handler will either
	be INTEVT2 (SH7705) or INTEVT (SH7305), but its value for each
	interrupt case is completely platform-dependent. Remember to handle
	both platforms for increased portability, if possible.
*/
void gint_setDefaultHandler(void (*new_handler)(int event_code))
{
	default_handler = new_handler;
}

/*
	gint_init()
	Initializes gint. Loads the interrupt handler into the memory and sets
	the new vbr address.
*/
void gint_init(void)
{
	// Linker script symbols -- gint.
	extern unsigned int
		gint_vbr,
		gint_data,
		bgint, egint;

	unsigned int *ptr = &bgint;
	unsigned int *src = &gint_data;

	// This initialization routine is usually called before any
	// constructor. We want to ensure that the MPU type is detected, but
	// mpu_init() hasn't been called yet.
	mpu_init();

	// Loading the interrupt handler into the memory.
	while(ptr < &egint) *ptr++ = *src++;

	sys_vbr = gint_getVBR();
	new_vbr = (unsigned int)&gint_vbr;

	gint_setVBR(new_vbr, gint_setup);
}

/*
	gint_quit()
	Stops gint. Restores the system's configuration and vbr address.
*/
void gint_quit(void)
{
	gint_setVBR(sys_vbr, gint_stop);
}



//---
//	VBR space.
//---

#include <display.h>
#define print(str, x, y) dtext(6 * (x) - 5, 8 * (y) - 7, str)
#define hexdigit(n) ((n) + '0' + 39 * ((n) > 9))

static void hex(unsigned int x, int digits, char *str)
{
	str[0] = '0';
	str[1] = 'x';
	str[digits + 2] = 0;

	while(digits)
	{
		str[digits + 1] = hexdigit(x & 0xf);
		x >>= 4;
		digits--;
	}
}

static void reverse(void)
{
	int *vram = display_getCurrentVRAM();
	int i;
	for(i = 0; i < 36; i++) vram[i] = ~vram[i];
}

/*
	gint_exc()
	Handles exceptions.
*/
void gint_exc(void)
{
	volatile unsigned int *expevt	= gint_reg(Register_EXPEVT);
	volatile unsigned int *tea	= gint_reg(Register_TEA);
	unsigned int spc;
	char str[11];

	text_configure(NULL, Color_Black);

	__asm__("\tstc spc, %0" : "=r"(spc));

	dclear();
	print("Exception raised!", 3, 1);
	reverse();
	print(gint_strerror(0), 2, 3);

	print("expevt", 2, 4);
	hex(*expevt, 3, str);
	print(str, 16, 4);

	print("pc", 2, 5);
	hex(spc, 8, str);
	print(str, 11, 5);

	print("tea", 2, 6);
	hex(*tea, 8, str);
	print(str, 11, 6);

	print("Please reset.", 2, 7);
	dupdate();
	while(1);
}

/*
	gint_tlb()
	Handles TLB misses.
*/
void gint_tlb(void)
{
	volatile unsigned int *expevt	= gint_reg(Register_EXPEVT);
	volatile unsigned int *tea	= gint_reg(Register_TEA);
	unsigned int spc;
	char str[11];

	text_configure(NULL, Color_Black);

	__asm__("\tstc spc, %0" : "=r"(spc));

	dclear();
	print("TLB error!", 6, 1);
	reverse();
	print(gint_strerror(1), 2, 3);

	print("expevt", 2, 4);
	hex(*expevt, 3, str);
	print(str, 16, 4);

	print("pc", 2, 5);
	hex(spc, 8, str);
	print(str, 11, 5);

	print("tea", 2, 6);
	hex(*tea, 8, str);
	print(str, 11, 6);

	print("Please reset.", 2, 7);
	dupdate();
	while(1);
}

/*
	gint_int()
	Handles interrupts.
*/
void gint_int(void)
{
	if(isSH3())
		gint_int_7705();
	else
		gint_int_7305();
}



//---
//	Internal API.
//---

/*
	gint_callDefaultHandler()
	Calls the user-provided default interrupt handler.
*/
void gint_callDefaultHandler(int event_code)
{
	if(default_handler) default_handler(event_code);
}

/*
	gint_reg()
	Returns the address of a common register. All common registers exist
	on both platforms but they may hold different values for the same
	information (f.i. EXPEVT may not return the same value for a given
	exception on both 7705 and 7305).
*/
inline volatile void *gint_reg(enum Register reg)
{
	if(isSH3())
		return gint_reg_7705(reg);
	else
		return gint_reg_7305(reg);
}

/*
	gint_strerror()
	Returns a string that describe the error set in EXPEVT. This string is
	not platform-dependent.
	Some exception codes represent different errors when invoked inside the
	general exception handler and the TLB error handler. Parameter 'is_tlb'
	should be set to zero for general exception meanings, and anything non-
	zero for TLB error meanings.
*/
const char *gint_strerror(int is_tlb)
{
	if(isSH3())
		return gint_strerror_7705(is_tlb);
	else
		return gint_strerror_7305();
}