/*
 * CBE Pervasive Monitor and Debug
 *
 * (C) Copyright IBM Corporation 2005
 *
 * Authors: Maximino Aguilar (maguilar@us.ibm.com)
 *          Michael N. Day (mnday@us.ibm.com)
 *
 * 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, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#undef DEBUG

#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/percpu.h>
#include <linux/types.h>
#include <linux/kallsyms.h>

#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/prom.h>
#include <asm/pgtable.h>
#include <asm/reg.h>

#include "pervasive.h"
#include "cbe_regs.h"

static int sysreset_hack;

static void cbe_power_save(void)
{
	unsigned long ctrl, thread_switch_control;

	/*
	 * We need to hard disable interrupts, the local_irq_enable() done by
	 * our caller upon return will hard re-enable.
	 */
	hard_irq_disable();

	ctrl = mfspr(SPRN_CTRLF);

	/* Enable DEC and EE interrupt request */
	thread_switch_control  = mfspr(SPRN_TSC_CELL);
	thread_switch_control |= TSC_CELL_EE_ENABLE | TSC_CELL_EE_BOOST;

	switch (ctrl & CTRL_CT) {
	case CTRL_CT0:
		thread_switch_control |= TSC_CELL_DEC_ENABLE_0;
		break;
	case CTRL_CT1:
		thread_switch_control |= TSC_CELL_DEC_ENABLE_1;
		break;
	default:
		printk(KERN_WARNING "%s: unknown configuration\n",
			__FUNCTION__);
		break;
	}
	mtspr(SPRN_TSC_CELL, thread_switch_control);

	/*
	 * go into low thread priority, medium priority will be
	 * restored for us after wake-up.
	 */
	HMT_low();

	/*
	 * atomically disable thread execution and runlatch.
	 * External and Decrementer exceptions are still handled when the
	 * thread is disabled but now enter in cbe_system_reset_exception()
	 */
	ctrl &= ~(CTRL_RUNLATCH | CTRL_TE);
	mtspr(SPRN_CTRLT, ctrl);
}

static int cbe_system_reset_exception(struct pt_regs *regs)
{
	int cpu;
	struct cbe_pmd_regs __iomem *pmd;

	switch (regs->msr & SRR1_WAKEMASK) {
	case SRR1_WAKEEE:
		do_IRQ(regs);
		break;
	case SRR1_WAKEDEC:
		timer_interrupt(regs);
		break;
	case SRR1_WAKEMT:
		/*
		 * The BMC can inject user triggered system reset exceptions,
		 * but cannot set the system reset reason in srr1,
		 * so check an extra register here.
		 */
		if (sysreset_hack && (cpu = smp_processor_id()) == 0) {
			pmd = cbe_get_cpu_pmd_regs(cpu);
			if (in_be64(&pmd->ras_esc_0) & 0xffff) {
				out_be64(&pmd->ras_esc_0, 0);
				return 0;
			}
		}
		break;
#ifdef CONFIG_CBE_RAS
	case SRR1_WAKESYSERR:
		cbe_system_error_exception(regs);
		break;
	case SRR1_WAKETHERM:
		cbe_thermal_exception(regs);
		break;
#endif /* CONFIG_CBE_RAS */
	default:
		/* do system reset */
		return 0;
	}
	/* everything handled */
	return 1;
}

void __init cbe_pervasive_init(void)
{
	int cpu;

	if (!cpu_has_feature(CPU_FTR_PAUSE_ZERO))
		return;

	sysreset_hack = machine_is_compatible("IBM,CBPLUS-1.0");

	for_each_possible_cpu(cpu) {
		struct cbe_pmd_regs __iomem *regs = cbe_get_cpu_pmd_regs(cpu);
		if (!regs)
			continue;

		 /* Enable Pause(0) control bit */
		out_be64(&regs->pmcr, in_be64(&regs->pmcr) |
					    CBE_PMD_PAUSE_ZERO_CONTROL);

		/* Enable JTAG system-reset hack */
		if (sysreset_hack)
			out_be32(&regs->fir_mode_reg,
				in_be32(&regs->fir_mode_reg) |
				CBE_PMD_FIR_MODE_M8);
	}

	ppc_md.power_save = cbe_power_save;
	ppc_md.system_reset_exception = cbe_system_reset_exception;
}