xref: /kernel/linux/linux-5.10/arch/powerpc/platforms/cell/pervasive.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * CBE Pervasive Monitor and Debug
 *
 * (C) Copyright IBM Corporation 2005
 *
 * Authors: Maximino Aguilar (maguilar@us.ibm.com)
 *          Michael N. Day (mnday@us.ibm.com)
 */

#undef DEBUG

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

#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/prom.h>
#include <asm/reg.h>
#include <asm/cell-regs.h>
#include <asm/cpu_has_feature.h>

#include "pervasive.h"

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

	/* Ensure our interrupt state is properly tracked */
	if (!prep_irq_for_idle())
		return;

	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",
			__func__);
		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);

	/* Re-enable interrupts in MSR */
	__hard_irq_enable();
}

static int cbe_system_reset_exception(struct pt_regs *regs)
{
	switch (regs->msr & SRR1_WAKEMASK) {
	case SRR1_WAKEDEC:
		set_dec(1);
		break;
	case SRR1_WAKEEE:
		/*
		 * Handle these when interrupts get re-enabled and we take
		 * them as regular exceptions. We are in an NMI context
		 * and can't handle these here.
		 */
		break;
	case SRR1_WAKEMT:
		return cbe_sysreset_hack();
#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;

	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);
	}

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