// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 1995  Linus Torvalds
 *  Adapted from 'alpha' version by Gary Thomas
 *  Modified by Cort Dougan (cort@cs.nmt.edu)
 *  Modified for MBX using prep/chrp/pmac functions by Dan (dmalek@jlc.net)
 *  Further modified for generic 8xx by Dan.
 */

/*
 * bootup setup stuff..
 */

#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/rtc.h>
#include <linux/fsl_devices.h>

#include <asm/io.h>
#include <asm/8xx_immap.h>
#include <asm/prom.h>
#include <asm/fs_pd.h>
#include <mm/mmu_decl.h>

#include "pic.h"

#include "mpc8xx.h"

extern int cpm_pic_init(void);
extern int cpm_get_irq(void);

/* A place holder for time base interrupts, if they are ever enabled. */
static irqreturn_t timebase_interrupt(int irq, void *dev)
{
        printk ("timebase_interrupt()\n");

        return IRQ_HANDLED;
}

static struct irqaction tbint_irqaction = {
        .handler = timebase_interrupt,
        .flags = IRQF_NO_THREAD,
        .name = "tbint",
};

/* per-board overridable init_internal_rtc() function. */
void __init __attribute__ ((weak))
init_internal_rtc(void)
{
        sit8xx_t __iomem *sys_tmr = immr_map(im_sit);

        /* Disable the RTC one second and alarm interrupts. */
        clrbits16(&sys_tmr->sit_rtcsc, (RTCSC_SIE | RTCSC_ALE));

        /* Enable the RTC */
        setbits16(&sys_tmr->sit_rtcsc, (RTCSC_RTF | RTCSC_RTE));
        immr_unmap(sys_tmr);
}

static int __init get_freq(char *name, unsigned long *val)
{
        struct device_node *cpu;
        const unsigned int *fp;
        int found = 0;

        /* The cpu node should have timebase and clock frequency properties */
        cpu = of_find_node_by_type(NULL, "cpu");

        if (cpu) {
                fp = of_get_property(cpu, name, NULL);
                if (fp) {
                        found = 1;
                        *val = *fp;
                }

                of_node_put(cpu);
        }

        return found;
}

/* The decrementer counts at the system (internal) clock frequency divided by
 * sixteen, or external oscillator divided by four.  We force the processor
 * to use system clock divided by sixteen.
 */
void __init mpc8xx_calibrate_decr(void)
{
        struct device_node *cpu;
        cark8xx_t __iomem *clk_r1;
        car8xx_t __iomem *clk_r2;
        sitk8xx_t __iomem *sys_tmr1;
        sit8xx_t __iomem *sys_tmr2;
        int irq, virq;

        clk_r1 = immr_map(im_clkrstk);

        /* Unlock the SCCR. */
        out_be32(&clk_r1->cark_sccrk, ~KAPWR_KEY);
        out_be32(&clk_r1->cark_sccrk, KAPWR_KEY);
        immr_unmap(clk_r1);

        /* Force all 8xx processors to use divide by 16 processor clock. */
        clk_r2 = immr_map(im_clkrst);
        setbits32(&clk_r2->car_sccr, 0x02000000);
        immr_unmap(clk_r2);

        /* Processor frequency is MHz.
         */
        ppc_proc_freq = 50000000;
        if (!get_freq("clock-frequency", &ppc_proc_freq))
                printk(KERN_ERR "WARNING: Estimating processor frequency "
                                "(not found)\n");

        ppc_tb_freq = ppc_proc_freq / 16;
        printk("Decrementer Frequency = 0x%lx\n", ppc_tb_freq);

        /* Perform some more timer/timebase initialization.  This used
         * to be done elsewhere, but other changes caused it to get
         * called more than once....that is a bad thing.
         *
         * First, unlock all of the registers we are going to modify.
         * To protect them from corruption during power down, registers
         * that are maintained by keep alive power are "locked".  To
         * modify these registers we have to write the key value to
         * the key location associated with the register.
         * Some boards power up with these unlocked, while others
         * are locked.  Writing anything (including the unlock code?)
         * to the unlocked registers will lock them again.  So, here
         * we guarantee the registers are locked, then we unlock them
         * for our use.
         */
        sys_tmr1 = immr_map(im_sitk);
        out_be32(&sys_tmr1->sitk_tbscrk, ~KAPWR_KEY);
        out_be32(&sys_tmr1->sitk_rtcsck, ~KAPWR_KEY);
        out_be32(&sys_tmr1->sitk_tbk, ~KAPWR_KEY);
        out_be32(&sys_tmr1->sitk_tbscrk, KAPWR_KEY);
        out_be32(&sys_tmr1->sitk_rtcsck, KAPWR_KEY);
        out_be32(&sys_tmr1->sitk_tbk, KAPWR_KEY);
        immr_unmap(sys_tmr1);

        init_internal_rtc();

        /* Enabling the decrementer also enables the timebase interrupts
         * (or from the other point of view, to get decrementer interrupts
         * we have to enable the timebase).  The decrementer interrupt
         * is wired into the vector table, nothing to do here for that.
         */
        cpu = of_find_node_by_type(NULL, "cpu");
        virq= irq_of_parse_and_map(cpu, 0);
        irq = virq_to_hw(virq);

        sys_tmr2 = immr_map(im_sit);
        out_be16(&sys_tmr2->sit_tbscr, ((1 << (7 - (irq/2))) << 8) |
                                        (TBSCR_TBF | TBSCR_TBE));
        immr_unmap(sys_tmr2);

        if (setup_irq(virq, &tbint_irqaction))
                panic("Could not allocate timer IRQ!");
}

/* The RTC on the MPC8xx is an internal register.
 * We want to protect this during power down, so we need to unlock,
 * modify, and re-lock.
 */

int mpc8xx_set_rtc_time(struct rtc_time *tm)
{
        sitk8xx_t __iomem *sys_tmr1;
        sit8xx_t __iomem *sys_tmr2;
        int time;

        sys_tmr1 = immr_map(im_sitk);
        sys_tmr2 = immr_map(im_sit);
        time = mktime(tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
                      tm->tm_hour, tm->tm_min, tm->tm_sec);

        out_be32(&sys_tmr1->sitk_rtck, KAPWR_KEY);
        out_be32(&sys_tmr2->sit_rtc, time);
        out_be32(&sys_tmr1->sitk_rtck, ~KAPWR_KEY);

        immr_unmap(sys_tmr2);
        immr_unmap(sys_tmr1);
        return 0;
}

void mpc8xx_get_rtc_time(struct rtc_time *tm)
{
        unsigned long data;
        sit8xx_t __iomem *sys_tmr = immr_map(im_sit);

        /* Get time from the RTC. */
        data = in_be32(&sys_tmr->sit_rtc);
        to_tm(data, tm);
        tm->tm_year -= 1900;
        tm->tm_mon -= 1;
        immr_unmap(sys_tmr);
        return;
}

void __noreturn mpc8xx_restart(char *cmd)
{
        car8xx_t __iomem *clk_r = immr_map(im_clkrst);


        local_irq_disable();

        setbits32(&clk_r->car_plprcr, 0x00000080);
        /* Clear the ME bit in MSR to cause checkstop on machine check
        */
        mtmsr(mfmsr() & ~0x1000);

        in_8(&clk_r->res[0]);
        panic("Restart failed\n");
}

static void cpm_cascade(struct irq_desc *desc)
{
        struct irq_chip *chip = irq_desc_get_chip(desc);
        int cascade_irq = cpm_get_irq();

        if (cascade_irq >= 0)
                generic_handle_irq(cascade_irq);

        chip->irq_eoi(&desc->irq_data);
}

/* Initialize the internal interrupt controllers.  The number of
 * interrupts supported can vary with the processor type, and the
 * 82xx family can have up to 64.
 * External interrupts can be either edge or level triggered, and
 * need to be initialized by the appropriate driver.
 */
void __init mpc8xx_pics_init(void)
{
        int irq;

        if (mpc8xx_pic_init()) {
                printk(KERN_ERR "Failed interrupt 8xx controller  initialization\n");
                return;
        }

        irq = cpm_pic_init();
        if (irq)
                irq_set_chained_handler(irq, cpm_cascade);
}