/*
 * U-boot - traps.c Routines related to interrupts and exceptions
 *
 * Copyright (c) 2005-2008 Analog Devices Inc.
 *
 * This file is based on
 * No original Copyright holder listed,
 * Probabily original (C) Roman Zippel (assigned DJD, 1999)
 *
 * Copyright 2003 Metrowerks - for Blackfin
 * Copyright 2000-2001 Lineo, Inc. D. Jeff Dionne <jeff@lineo.ca>
 * Copyright 1999-2000 D. Jeff Dionne, <jeff@uclinux.org>
 *
 * (C) Copyright 2000-2004
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * Licensed under the GPL-2 or later.
 */

#include <common.h>
#include <kgdb.h>
#include <linux/types.h>
#include <asm/traps.h>
#include <asm/cplb.h>
#include <asm/io.h>
#include <asm/mach-common/bits/core.h>
#include <asm/mach-common/bits/mpu.h>
#include <asm/mach-common/bits/trace.h>
#include <asm/deferred.h>
#include "cpu.h"

#ifdef CONFIG_DEBUG_DUMP
# define ENABLE_DUMP 1
#else
# define ENABLE_DUMP 0
#endif

#define trace_buffer_save(x) \
	do { \
		if (!ENABLE_DUMP) \
			break; \
		(x) = bfin_read_TBUFCTL(); \
		bfin_write_TBUFCTL((x) & ~TBUFEN); \
	} while (0)

#define trace_buffer_restore(x) \
	do { \
		if (!ENABLE_DUMP) \
			break; \
		bfin_write_TBUFCTL((x)); \
	} while (0);

/* The purpose of this map is to provide a mapping of address<->cplb settings
 * rather than an exact map of what is actually addressable on the part.  This
 * map covers all current Blackfin parts.  If you try to access an address that
 * is in this map but not actually on the part, you won't get an exception and
 * reboot, you'll get an external hardware addressing error and reboot.  Since
 * only the ends matter (you did something wrong and the board reset), the means
 * are largely irrelevant.
 */
struct memory_map {
	uint32_t start, end;
	uint32_t data_flags, inst_flags;
};
const struct memory_map const bfin_memory_map[] = {
	{	/* external memory */
		.start = 0x00000000,
		.end   = 0x20000000,
		.data_flags = SDRAM_DGENERIC,
		.inst_flags = SDRAM_IGENERIC,
	},
	{	/* async banks */
		.start = 0x20000000,
		.end   = 0x30000000,
		.data_flags = SDRAM_EBIU,
		.inst_flags = SDRAM_INON_CHBL,
	},
	{	/* everything on chip */
		.start = 0xE0000000,
		.end   = 0xFFFFFFFF,
		.data_flags = L1_DMEMORY,
		.inst_flags = L1_IMEMORY,
	}
};

#ifdef CONFIG_EXCEPTION_DEFER
unsigned int deferred_regs[deferred_regs_last];
#endif

/*
 * Handle all exceptions while running in EVT3 or EVT5
 */
int trap_c(struct pt_regs *regs, uint32_t level)
{
	uint32_t ret = 0;
	uint32_t trapnr = (regs->seqstat & EXCAUSE);
	unsigned long tflags;
	bool data = false;

	/*
	 * Keep the trace buffer so that a miss here points people
	 * to the right place (their code).  Crashes here rarely
	 * happen.  If they do, only the Blackfin maintainer cares.
	 */
	trace_buffer_save(tflags);

	switch (trapnr) {
	/* 0x26 - Data CPLB Miss */
	case VEC_CPLB_M:

		if (ANOMALY_05000261) {
			static uint32_t last_cplb_fault_retx;
			/*
			 * Work around an anomaly: if we see a new DCPLB fault,
			 * return without doing anything. Then,
			 * if we get the same fault again, handle it.
			 */
			if (last_cplb_fault_retx != regs->retx) {
				last_cplb_fault_retx = regs->retx;
				break;
			}
		}

		data = true;
		/* fall through */

	/* 0x27 - Instruction CPLB Miss */
	case VEC_CPLB_I_M: {
		volatile uint32_t *CPLB_ADDR_BASE, *CPLB_DATA_BASE, *CPLB_ADDR, *CPLB_DATA;
		uint32_t new_cplb_addr = 0, new_cplb_data = 0;
		static size_t last_evicted;
		size_t i;

#ifdef CONFIG_EXCEPTION_DEFER
		/* This should never happen */
		if (level == 5)
			bfin_panic(regs);
#endif

		new_cplb_addr = (data ? bfin_read_DCPLB_FAULT_ADDR() : bfin_read_ICPLB_FAULT_ADDR()) & ~(4 * 1024 * 1024 - 1);

		for (i = 0; i < ARRAY_SIZE(bfin_memory_map); ++i) {
			/* if the exception is inside this range, lets use it */
			if (new_cplb_addr >= bfin_memory_map[i].start &&
			    new_cplb_addr < bfin_memory_map[i].end)
				break;
		}
		if (i == ARRAY_SIZE(bfin_memory_map)) {
			printf("%cCPLB exception outside of memory map at 0x%p\n",
				(data ? 'D' : 'I'), (void *)new_cplb_addr);
			bfin_panic(regs);
		} else
			debug("CPLB addr %p matches map 0x%p - 0x%p\n",
				(void *)new_cplb_addr,
				(void *)bfin_memory_map[i].start,
				(void *)bfin_memory_map[i].end);
		new_cplb_data = (data ? bfin_memory_map[i].data_flags : bfin_memory_map[i].inst_flags);

		if (data) {
			CPLB_ADDR_BASE = (uint32_t *)DCPLB_ADDR0;
			CPLB_DATA_BASE = (uint32_t *)DCPLB_DATA0;
		} else {
			CPLB_ADDR_BASE = (uint32_t *)ICPLB_ADDR0;
			CPLB_DATA_BASE = (uint32_t *)ICPLB_DATA0;
		}

		/* find the next unlocked entry and evict it */
		i = last_evicted & 0xF;
		debug("last evicted = %zu\n", i);
		CPLB_DATA = CPLB_DATA_BASE + i;
		while (*CPLB_DATA & CPLB_LOCK) {
			debug("skipping %zu %p - %08X\n", i, CPLB_DATA, *CPLB_DATA);
			i = (i + 1) & 0xF;	/* wrap around */
			CPLB_DATA = CPLB_DATA_BASE + i;
		}
		CPLB_ADDR = CPLB_ADDR_BASE + i;

		debug("evicting entry %zu: 0x%p 0x%08X\n", i,
			(void *)*CPLB_ADDR, *CPLB_DATA);
		last_evicted = i + 1;

		/* need to turn off cplbs whenever we muck with the cplb table */
#if ENDCPLB != ENICPLB
# error cplb enable bit violates my sanity
#endif
		uint32_t mem_control = (data ? DMEM_CONTROL : IMEM_CONTROL);
		bfin_write32(mem_control, bfin_read32(mem_control) & ~ENDCPLB);
		*CPLB_ADDR = new_cplb_addr;
		*CPLB_DATA = new_cplb_data;
		bfin_write32(mem_control, bfin_read32(mem_control) | ENDCPLB);
		SSYNC();

		/* dump current table for debugging purposes */
		CPLB_ADDR = CPLB_ADDR_BASE;
		CPLB_DATA = CPLB_DATA_BASE;
		for (i = 0; i < 16; ++i)
			debug("%2zu 0x%p 0x%08X\n", i,
				(void *)*CPLB_ADDR++, *CPLB_DATA++);

		break;
	}
#ifdef CONFIG_CMD_KGDB
	/* Single step
	 * if we are in IRQ5, just ignore, otherwise defer, and handle it in kgdb
	 */
	case VEC_STEP:
		if (level == 3) {
			/* If we just returned from an interrupt, the single step
			 * event is for the RTI instruction.
			 */
			if (regs->retx == regs->pc)
				break;
			/* we just return if we are single stepping through IRQ5 */
			if (regs->ipend & 0x20)
				break;
			/* Otherwise, turn single stepping off & fall through,
			 * which defers to IRQ5
			 */
			regs->syscfg &= ~1;
		}
		/* fall through */
#endif
	default:
#ifdef CONFIG_CMD_KGDB
		if (level == 3) {
			/* We need to handle this at EVT5, so try again */
			bfin_dump(regs);
			ret = 1;
			break;
		}
		if (debugger_exception_handler && (*debugger_exception_handler)(regs))
			break;
#endif
		bfin_panic(regs);
	}

	trace_buffer_restore(tflags);

	return ret;
}

#ifndef CONFIG_KALLSYMS
const char *symbol_lookup(unsigned long addr, unsigned long *caddr)
{
	*caddr = addr;
	return "N/A";
}
#endif

static void decode_address(char *buf, unsigned long address)
{
	unsigned long sym_addr;
	void *paddr = (void *)address;
	const char *sym = symbol_lookup(address, &sym_addr);

	if (sym) {
		sprintf(buf, "<0x%p> { %s + 0x%lx }", paddr, sym, address - sym_addr);
		return;
	}

	if (!address)
		sprintf(buf, "<0x%p> /* Maybe null pointer? */", paddr);
	else if (address >= CONFIG_SYS_MONITOR_BASE &&
	         address < CONFIG_SYS_MONITOR_BASE + CONFIG_SYS_MONITOR_LEN)
		sprintf(buf, "<0x%p> /* somewhere in u-boot */", paddr);
	else
		sprintf(buf, "<0x%p> /* unknown address */", paddr);
}

static char *strhwerrcause(uint16_t hwerrcause)
{
	switch (hwerrcause) {
		case 0x02: return "system mmr error";
		case 0x03: return "external memory addressing error";
		case 0x12: return "performance monitor overflow";
		case 0x18: return "raise 5 instruction";
		default:   return "undef";
	}
}

static char *strexcause(uint16_t excause)
{
	switch (excause) {
		case 0x00 ... 0xf: return "custom exception";
		case 0x10: return "single step";
		case 0x11: return "trace buffer full";
		case 0x21: return "undef inst";
		case 0x22: return "illegal inst";
		case 0x23: return "dcplb prot violation";
		case 0x24: return "misaligned data";
		case 0x25: return "unrecoverable event";
		case 0x26: return "dcplb miss";
		case 0x27: return "multiple dcplb hit";
		case 0x28: return "emulation watchpoint";
		case 0x2a: return "misaligned inst";
		case 0x2b: return "icplb prot violation";
		case 0x2c: return "icplb miss";
		case 0x2d: return "multiple icplb hit";
		case 0x2e: return "illegal use of supervisor resource";
		default:   return "undef";
	}
}

void dump(struct pt_regs *fp)
{
	char buf[150];
	int i;
	uint16_t hwerrcause, excause;

	if (!ENABLE_DUMP)
		return;

#ifndef CONFIG_CMD_KGDB
	/* fp->ipend is normally garbage, so load it ourself */
	fp->ipend = bfin_read_IPEND();
#endif

	hwerrcause = (fp->seqstat & HWERRCAUSE) >> HWERRCAUSE_P;
	excause = (fp->seqstat & EXCAUSE) >> EXCAUSE_P;

	printf("SEQUENCER STATUS:\n");
	printf(" SEQSTAT: %08lx  IPEND: %04lx  SYSCFG: %04lx\n",
		fp->seqstat, fp->ipend, fp->syscfg);
	printf("  HWERRCAUSE: 0x%x: %s\n", hwerrcause, strhwerrcause(hwerrcause));
	printf("  EXCAUSE   : 0x%x: %s\n", excause, strexcause(excause));
	for (i = 6; i <= 15; ++i) {
		if (fp->ipend & (1 << i)) {
			decode_address(buf, bfin_read32(EVT0 + 4*i));
			printf("  physical IVG%i asserted : %s\n", i, buf);
		}
	}
	decode_address(buf, fp->rete);
	printf(" RETE: %s\n", buf);
	decode_address(buf, fp->retn);
	printf(" RETN: %s\n", buf);
	decode_address(buf, fp->retx);
	printf(" RETX: %s\n", buf);
	decode_address(buf, fp->rets);
	printf(" RETS: %s\n", buf);
	/* we lie and store RETI in "pc" */
	decode_address(buf, fp->pc);
	printf(" RETI: %s\n", buf);

	if (fp->seqstat & EXCAUSE) {
		decode_address(buf, bfin_read_DCPLB_FAULT_ADDR());
		printf("DCPLB_FAULT_ADDR: %s\n", buf);
		decode_address(buf, bfin_read_ICPLB_FAULT_ADDR());
		printf("ICPLB_FAULT_ADDR: %s\n", buf);
	}

	printf("\nPROCESSOR STATE:\n");
	printf(" R0 : %08lx    R1 : %08lx    R2 : %08lx    R3 : %08lx\n",
		fp->r0, fp->r1, fp->r2, fp->r3);
	printf(" R4 : %08lx    R5 : %08lx    R6 : %08lx    R7 : %08lx\n",
		fp->r4, fp->r5, fp->r6, fp->r7);
	printf(" P0 : %08lx    P1 : %08lx    P2 : %08lx    P3 : %08lx\n",
		fp->p0, fp->p1, fp->p2, fp->p3);
	printf(" P4 : %08lx    P5 : %08lx    FP : %08lx    SP : %08lx\n",
		fp->p4, fp->p5, fp->fp, (unsigned long)fp);
	printf(" LB0: %08lx    LT0: %08lx    LC0: %08lx\n",
		fp->lb0, fp->lt0, fp->lc0);
	printf(" LB1: %08lx    LT1: %08lx    LC1: %08lx\n",
		fp->lb1, fp->lt1, fp->lc1);
	printf(" B0 : %08lx    L0 : %08lx    M0 : %08lx    I0 : %08lx\n",
		fp->b0, fp->l0, fp->m0, fp->i0);
	printf(" B1 : %08lx    L1 : %08lx    M1 : %08lx    I1 : %08lx\n",
		fp->b1, fp->l1, fp->m1, fp->i1);
	printf(" B2 : %08lx    L2 : %08lx    M2 : %08lx    I2 : %08lx\n",
		fp->b2, fp->l2, fp->m2, fp->i2);
	printf(" B3 : %08lx    L3 : %08lx    M3 : %08lx    I3 : %08lx\n",
		fp->b3, fp->l3, fp->m3, fp->i3);
	printf("A0.w: %08lx   A0.x: %08lx   A1.w: %08lx   A1.x: %08lx\n",
		fp->a0w, fp->a0x, fp->a1w, fp->a1x);

	printf("USP : %08lx  ASTAT: %08lx\n",
		fp->usp, fp->astat);

	printf("\n");
}

static void _dump_bfin_trace_buffer(void)
{
	char buf[150];
	int i = 0;

	if (!ENABLE_DUMP)
		return;

	printf("Hardware Trace:\n");

	if (bfin_read_TBUFSTAT() & TBUFCNT) {
		for (; bfin_read_TBUFSTAT() & TBUFCNT; i++) {
			decode_address(buf, bfin_read_TBUF());
			printf("%4i Target : %s\n", i, buf);
			decode_address(buf, bfin_read_TBUF());
			printf("     Source : %s\n", buf);
		}
	}
}

void dump_bfin_trace_buffer(void)
{
	unsigned long tflags;
	trace_buffer_save(tflags);
	_dump_bfin_trace_buffer();
	trace_buffer_restore(tflags);
}

void bfin_dump(struct pt_regs *regs)
{
	unsigned long tflags;

	trace_buffer_save(tflags);

	puts(
		"\n"
		"\n"
		"\n"
		"Ack! Something bad happened to the Blackfin!\n"
		"\n"
	);
	dump(regs);
	_dump_bfin_trace_buffer();
	puts("\n");

	trace_buffer_restore(tflags);
}

void bfin_panic(struct pt_regs *regs)
{
	unsigned long tflags;
	trace_buffer_save(tflags);
	bfin_dump(regs);
	panic("PANIC: Blackfin internal error");
}