/*
 * BK Id: %F% %I% %G% %U% %#%
 */
/*
 * SMP support for power macintosh.
 *
 * We support both the old "powersurge" SMP architecture
 * and the current Core99 (G4 PowerMac) machines.
 *
 * Support Macintosh G4 SMP by Troy Benjegerdes (hozer@drgw.net)
 * and Ben Herrenschmidt <benh@kernel.crashing.org>.
 *
 * Support for DayStar quad CPU cards
 * Copyright (C) XLR8, Inc. 1994-2000
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/delay.h>
#define __KERNEL_SYSCALLS__
#include <linux/unistd.h>
#include <linux/init.h>
#include <linux/spinlock.h>

#include <asm/ptrace.h>
#include <asm/atomic.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/hardirq.h>
#include <asm/softirq.h>
#include <asm/sections.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/residual.h>
#include <asm/machdep.h>
#include <asm/pmac_feature.h>
#include <asm/time.h>
#include <asm/open_pic.h>

/*
 * Powersurge (old powermac SMP) support.
 */

extern void __secondary_start_psurge(void);
extern void __secondary_start_psurge2(void);	/* Temporary horrible hack */
extern void __secondary_start_psurge3(void);	/* Temporary horrible hack */

/* Addresses for powersurge registers */
#define HAMMERHEAD_BASE		0xf8000000
#define HHEAD_CONFIG		0x90
#define HHEAD_SEC_INTR		0xc0

/* register for interrupting the primary processor on the powersurge */
/* N.B. this is actually the ethernet ROM! */
#define PSURGE_PRI_INTR		0xf3019000

/* register for storing the start address for the secondary processor */
/* N.B. this is the PCI config space address register for the 1st bridge */
#define PSURGE_START		0xf2800000

/* Daystar/XLR8 4-CPU card */
#define PSURGE_QUAD_REG_ADDR	0xf8800000

#define PSURGE_QUAD_IRQ_SET	0
#define PSURGE_QUAD_IRQ_CLR	1
#define PSURGE_QUAD_IRQ_PRIMARY	2
#define PSURGE_QUAD_CKSTOP_CTL	3
#define PSURGE_QUAD_PRIMARY_ARB	4
#define PSURGE_QUAD_BOARD_ID	6
#define PSURGE_QUAD_WHICH_CPU	7
#define PSURGE_QUAD_CKSTOP_RDBK	8
#define PSURGE_QUAD_RESET_CTL	11

#define PSURGE_QUAD_OUT(r, v)	(out_8(quad_base + ((r) << 4) + 4, (v)))
#define PSURGE_QUAD_IN(r)	(in_8(quad_base + ((r) << 4) + 4) & 0x0f)
#define PSURGE_QUAD_BIS(r, v)	(PSURGE_QUAD_OUT((r), PSURGE_QUAD_IN(r) | (v)))
#define PSURGE_QUAD_BIC(r, v)	(PSURGE_QUAD_OUT((r), PSURGE_QUAD_IN(r) & ~(v)))

/* virtual addresses for the above */
static volatile u8 *hhead_base;
static volatile u8 *quad_base;
static volatile u32 *psurge_pri_intr;
static volatile u8 *psurge_sec_intr;
static volatile u32 *psurge_start;

/* what sort of powersurge board we have */
static int psurge_type;

/* values for psurge_type */
#define PSURGE_DUAL		0
#define PSURGE_QUAD_OKEE	1
#define PSURGE_QUAD_COTTON	2
#define PSURGE_QUAD_ICEGRASS	3

/* l2 cache stuff for dual G4 macs */
extern void core99_init_l2(void);

/*
 * Set and clear IPIs for powersurge.
 */
static inline void psurge_set_ipi(int cpu)
{
	if (cpu == 0)
		in_be32(psurge_pri_intr);
	else if (psurge_type == PSURGE_DUAL)
		out_8(psurge_sec_intr, 0);
	else
		PSURGE_QUAD_OUT(PSURGE_QUAD_IRQ_SET, 1 << cpu);
}

static inline void psurge_clr_ipi(int cpu)
{
	if (cpu > 0) {
		if (psurge_type == PSURGE_DUAL)
			out_8(psurge_sec_intr, ~0);
		else
			PSURGE_QUAD_OUT(PSURGE_QUAD_IRQ_CLR, 1 << cpu);
	}
}

/*
 * On powersurge (old SMP powermac architecture) we don't have
 * separate IPIs for separate messages like openpic does.  Instead
 * we have a bitmap for each processor, where a 1 bit means that
 * the corresponding message is pending for that processor.
 * Ideally each cpu's entry would be in a different cache line.
 *  -- paulus.
 */
static unsigned long psurge_smp_message[NR_CPUS];

void __pmac
psurge_smp_message_recv(struct pt_regs *regs)
{
	int cpu = smp_processor_id();
	int msg;

	/* clear interrupt */
	psurge_clr_ipi(cpu);

	if (smp_num_cpus < 2)
		return;

	/* make sure there is a message there */
	for (msg = 0; msg < 4; msg++)
		if (test_and_clear_bit(msg, &psurge_smp_message[cpu]))
			smp_message_recv(msg, regs);
}

void __pmac
psurge_primary_intr(int irq, void *d, struct pt_regs *regs)
{
	psurge_smp_message_recv(regs);
}

static void __pmac
smp_psurge_message_pass(int target, int msg, unsigned long data, int wait)
{
	int i;

	if (smp_num_cpus < 2)
		return;

	for (i = 0; i < smp_num_cpus; i++) {
		if (target == MSG_ALL
		    || (target == MSG_ALL_BUT_SELF && i != smp_processor_id())
		    || target == i) {
			set_bit(msg, &psurge_smp_message[i]);
			psurge_set_ipi(i);
		}
	}
}

/*
 * Determine a quad card presence. We read the board ID register, we
 * force the data bus to change to something else, and we read it again.
 * It it's stable, then the register probably exist (ugh !)
 */
static int __init psurge_quad_probe(void)
{
	int type;
	unsigned int i;

	type = PSURGE_QUAD_IN(PSURGE_QUAD_BOARD_ID);
	if (type < PSURGE_QUAD_OKEE || type > PSURGE_QUAD_ICEGRASS
	    || type != PSURGE_QUAD_IN(PSURGE_QUAD_BOARD_ID))
		return PSURGE_DUAL;

	/* looks OK, try a slightly more rigorous test */
	/* bogus is not necessarily cacheline-aligned,
	   though I don't suppose that really matters.  -- paulus */
	for (i = 0; i < 100; i++) {
		volatile u32 bogus[8];
		bogus[(0+i)%8] = 0x00000000;
		bogus[(1+i)%8] = 0x55555555;
		bogus[(2+i)%8] = 0xFFFFFFFF;
		bogus[(3+i)%8] = 0xAAAAAAAA;
		bogus[(4+i)%8] = 0x33333333;
		bogus[(5+i)%8] = 0xCCCCCCCC;
		bogus[(6+i)%8] = 0xCCCCCCCC;
		bogus[(7+i)%8] = 0x33333333;
		wmb();
		asm volatile("dcbf 0,%0" : : "r" (bogus) : "memory");
		mb();
		if (type != PSURGE_QUAD_IN(PSURGE_QUAD_BOARD_ID))
			return PSURGE_DUAL;
	}
	return type;
}

static void __init psurge_quad_init(void)
{
	int procbits;

	if (ppc_md.progress) ppc_md.progress("psurge_quad_init", 0x351);
	procbits = ~PSURGE_QUAD_IN(PSURGE_QUAD_WHICH_CPU);
	if (psurge_type == PSURGE_QUAD_ICEGRASS)
		PSURGE_QUAD_BIS(PSURGE_QUAD_RESET_CTL, procbits);
	else
		PSURGE_QUAD_BIC(PSURGE_QUAD_CKSTOP_CTL, procbits);
	mdelay(33);
	out_8(psurge_sec_intr, ~0);
	PSURGE_QUAD_OUT(PSURGE_QUAD_IRQ_CLR, procbits);
	PSURGE_QUAD_BIS(PSURGE_QUAD_RESET_CTL, procbits);
	if (psurge_type != PSURGE_QUAD_ICEGRASS)
		PSURGE_QUAD_BIS(PSURGE_QUAD_CKSTOP_CTL, procbits);
	PSURGE_QUAD_BIC(PSURGE_QUAD_PRIMARY_ARB, procbits);
	mdelay(33);
	PSURGE_QUAD_BIC(PSURGE_QUAD_RESET_CTL, procbits);
	mdelay(33);
	PSURGE_QUAD_BIS(PSURGE_QUAD_PRIMARY_ARB, procbits);
	mdelay(33);
}

static int __init smp_psurge_probe(void)
{
	int i, ncpus;

	/* We don't do SMP on the PPC601 -- paulus */
	if (PVR_VER(mfspr(PVR)) == 1)
		return 1;

	/*
	 * The powersurge cpu board can be used in the generation
	 * of powermacs that have a socket for an upgradeable cpu card,
	 * including the 7500, 8500, 9500, 9600.
	 * The device tree doesn't tell you if you have 2 cpus because
	 * OF doesn't know anything about the 2nd processor.
	 * Instead we look for magic bits in magic registers,
	 * in the hammerhead memory controller in the case of the
	 * dual-cpu powersurge board.  -- paulus.
	 */
	if (find_devices("hammerhead") == NULL)
		return 1;

	hhead_base = ioremap(HAMMERHEAD_BASE, 0x800);
	quad_base = ioremap(PSURGE_QUAD_REG_ADDR, 1024);
	psurge_sec_intr = hhead_base + HHEAD_SEC_INTR;

	psurge_type = psurge_quad_probe();
	if (psurge_type != PSURGE_DUAL) {
		psurge_quad_init();
		/* All released cards using this HW design have 4 CPUs */
		ncpus = 4;
	} else {
		iounmap((void *) quad_base);
		if ((in_8(hhead_base + HHEAD_CONFIG) & 0x02) == 0) {
			/* not a dual-cpu card */
			iounmap((void *) hhead_base);
			return 1;
		}
		ncpus = 2;
	}

	psurge_start = ioremap(PSURGE_START, 4);
	psurge_pri_intr = ioremap(PSURGE_PRI_INTR, 4);

	/* this is not actually strictly necessary -- paulus. */
	for (i = 1; i < ncpus; ++i)
		smp_hw_index[i] = i;

	if (ppc_md.progress) ppc_md.progress("smp_psurge_probe - done", 0x352);

	return ncpus;
}

static void __init smp_psurge_kick_cpu(int nr)
{
	void (*start)(void) = __secondary_start_psurge;
	unsigned long a;

	/* may need to flush here if secondary bats aren't setup */
	for (a = KERNELBASE; a < KERNELBASE + 0x800000; a += 32)
		asm volatile("dcbf 0,%0" : : "r" (a) : "memory");
	asm volatile("sync");

	if (ppc_md.progress) ppc_md.progress("smp_psurge_kick_cpu", 0x353);

	/* setup entry point of secondary processor */
	switch (nr) {
	case 2:
		start = __secondary_start_psurge2;
		break;
	case 3:
		start = __secondary_start_psurge3;
		break;
	}

	out_be32(psurge_start, __pa(start));
	mb();

	psurge_set_ipi(nr);
	udelay(10);
	psurge_clr_ipi(nr);

	if (ppc_md.progress) ppc_md.progress("smp_psurge_kick_cpu - done", 0x354);
}

/*
 * With the dual-cpu powersurge board, the decrementers and timebases
 * of both cpus are frozen after the secondary cpu is started up,
 * until we give the secondary cpu another interrupt.  This routine
 * uses this to get the timebases synchronized.
 *  -- paulus.
 */
static void __init psurge_dual_sync_tb(int cpu_nr)
{
	static volatile int sec_tb_reset = 0;
	int t;

	set_dec(tb_ticks_per_jiffy);
	set_tb(0, 0);
	last_jiffy_stamp(cpu_nr) = 0;

	if (cpu_nr > 0) {
		mb();
		sec_tb_reset = 1;
		return;
	}

	/* wait for the secondary to have reset its TB before proceeding */
	for (t = 10000000; t > 0 && !sec_tb_reset; --t)
		;

	/* now interrupt the secondary, starting both TBs */
	psurge_set_ipi(1);

	smp_tb_synchronized = 1;
}

static void __init
smp_psurge_setup_cpu(int cpu_nr)
{

	if (cpu_nr == 0) {
		if (smp_num_cpus < 2)
			return;
		/* reset the entry point so if we get another intr we won't
		 * try to startup again */
		out_be32(psurge_start, 0x100);
		if (request_irq(30, psurge_primary_intr, 0, "primary IPI", 0))
			printk(KERN_ERR "Couldn't get primary IPI interrupt");
	}

	if (psurge_type == PSURGE_DUAL)
		psurge_dual_sync_tb(cpu_nr);
}

static int __init
smp_core99_probe(void)
{
	struct device_node *cpus;
	int i, ncpus = 1;

	if (ppc_md.progress) ppc_md.progress("smp_core99_probe", 0x345);
	cpus = find_type_devices("cpu");
	if (cpus)
		while ((cpus = cpus->next) != NULL)
			++ncpus;
	printk("smp_core99_probe: found %d cpus\n", ncpus);
	if (ncpus > 1) {
		openpic_request_IPIs();
		for (i = 1; i < ncpus; ++i)
			smp_hw_index[i] = i;
	}

	return ncpus;
}

static void __init
smp_core99_kick_cpu(int nr)
{
	unsigned long save_vector, new_vector;
	unsigned long flags;
#if 1 /* New way... */
	volatile unsigned long *vector
		 = ((volatile unsigned long *)(KERNELBASE+0x100));
	if (nr < 1 || nr > 3)
		return;
#else
	volatile unsigned long *vector
		 = ((volatile unsigned long *)(KERNELBASE+0x500));
	if (nr != 1)
		return;
#endif
	if (ppc_md.progress) ppc_md.progress("smp_core99_kick_cpu", 0x346);

	local_irq_save(flags);
	local_irq_disable();
	
	/* Save reset vector */
	save_vector = *vector;
	
	/* Setup fake reset vector that does	  
	 *   b __secondary_start_psurge - KERNELBASE
	 */  
	switch(nr) {
		case 1:
			new_vector = (unsigned long)__secondary_start_psurge;
			break;
		case 2:
			new_vector = (unsigned long)__secondary_start_psurge2;
			break;
		case 3:
			new_vector = (unsigned long)__secondary_start_psurge3;
			break;
	}
	*vector = 0x48000002 + new_vector - KERNELBASE;
	
	/* flush data cache and inval instruction cache */
	flush_icache_range((unsigned long) vector, (unsigned long) vector + 4);
	
	/* Put some life in our friend */
	pmac_call_feature(PMAC_FTR_RESET_CPU, NULL, nr, 0);
	
	/* FIXME: We wait a bit for the CPU to take the exception, I should
	 * instead wait for the entry code to set something for me. Well,
	 * ideally, all that crap will be done in prom.c and the CPU left
	 * in a RAM-based wait loop like CHRP.
	 */
	mdelay(1);
	
	/* Restore our exception vector */
	*vector = save_vector;
	flush_icache_range((unsigned long) vector, (unsigned long) vector + 4);
	
	local_irq_restore(flags);
	if (ppc_md.progress) ppc_md.progress("smp_core99_kick_cpu done", 0x347);
}

static void __init
smp_core99_setup_cpu(int cpu_nr)
{
	/* Setup openpic */
	do_openpic_setup_cpu();

	/* Setup L2 */
	if (cpu_nr != 0)
		core99_init_l2();
	else
		if (ppc_md.progress) ppc_md.progress("core99_setup_cpu 0 done", 0x349);
}

/* PowerSurge-style Macs */
struct smp_ops_t psurge_smp_ops __pmacdata = {
	smp_psurge_message_pass,
	smp_psurge_probe,
	smp_psurge_kick_cpu,
	smp_psurge_setup_cpu,
};

/* Core99 Macs (dual G4s) */
struct smp_ops_t core99_smp_ops __pmacdata = {
	smp_openpic_message_pass,
	smp_core99_probe,
	smp_core99_kick_cpu,
	smp_core99_setup_cpu,
};
