/*
 * ip22-mc.c: Routines for manipulating SGI Memory Controller.
 *
 * Copyright (C) 1996 David S. Miller (dm@engr.sgi.com)
 * Copyright (C) 1999 Andrew R. Baker (andrewb@uab.edu) - Indigo2 changes
 * Copyright (C) 2003 Ladislav Michl  (ladis@linux-mips.org)
 * Copyright (C) 2004 Peter Fuerst    (pf@net.alphadv.de) - IP28
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>

#include <asm/io.h>
#include <asm/bootinfo.h>
#include <asm/sgialib.h>
#include <asm/sgi/mc.h>
#include <asm/sgi/hpc3.h>
#include <asm/sgi/ip22.h>

struct sgimc_regs *sgimc;

EXPORT_SYMBOL(sgimc);

static inline unsigned long get_bank_addr(unsigned int memconfig)
{
        return ((memconfig & SGIMC_MCONFIG_BASEADDR) <<
                ((sgimc->systemid & SGIMC_SYSID_MASKREV) >= 5 ? 24 : 22));
}

static inline unsigned long get_bank_size(unsigned int memconfig)
{
        return ((memconfig & SGIMC_MCONFIG_RMASK) + 0x0100) <<
                ((sgimc->systemid & SGIMC_SYSID_MASKREV) >= 5 ? 16 : 14);
}

static inline unsigned int get_bank_config(int bank)
{
        unsigned int res = bank > 1 ? sgimc->mconfig1 : sgimc->mconfig0;
        return bank % 2 ? res & 0xffff : res >> 16;
}

struct mem {
        unsigned long addr;
        unsigned long size;
};

/*
 * Detect installed memory, do some sanity checks and notify kernel about it
 */
static void __init probe_memory(void)
{
        int i, j, found, cnt = 0;
        struct mem bank[4];
        struct mem space[2] = {{SGIMC_SEG0_BADDR, 0}, {SGIMC_SEG1_BADDR, 0}};

        printk(KERN_INFO "MC: Probing memory configuration:\n");
        for (i = 0; i < ARRAY_SIZE(bank); i++) {
                unsigned int tmp = get_bank_config(i);
                if (!(tmp & SGIMC_MCONFIG_BVALID))
                        continue;

                bank[cnt].size = get_bank_size(tmp);
                bank[cnt].addr = get_bank_addr(tmp);
                printk(KERN_INFO " bank%d: %3ldM @ %08lx\n",
                        i, bank[cnt].size / 1024 / 1024, bank[cnt].addr);
                cnt++;
        }

        /* And you thought bubble sort is dead algorithm... */
        do {
                unsigned long addr, size;

                found = 0;
                for (i = 1; i < cnt; i++)
                        if (bank[i-1].addr > bank[i].addr) {
                                addr = bank[i].addr;
                                size = bank[i].size;
                                bank[i].addr = bank[i-1].addr;
                                bank[i].size = bank[i-1].size;
                                bank[i-1].addr = addr;
                                bank[i-1].size = size;
                                found = 1;
                        }
        } while (found);

        /* Figure out how are memory banks mapped into spaces */
        for (i = 0; i < cnt; i++) {
                found = 0;
                for (j = 0; j < ARRAY_SIZE(space) && !found; j++)
                        if (space[j].addr + space[j].size == bank[i].addr) {
                                space[j].size += bank[i].size;
                                found = 1;
                        }
                /* There is either hole or overlapping memory */
                if (!found)
                        printk(KERN_CRIT "MC: Memory configuration mismatch "
                                         "(%08lx), expect Bus Error soon\n",
                                         bank[i].addr);
        }

        for (i = 0; i < ARRAY_SIZE(space); i++)
                if (space[i].size)
                        add_memory_region(space[i].addr, space[i].size,
                                          BOOT_MEM_RAM);
}

void __init sgimc_init(void)
{
        u32 tmp;

        /* ioremap can't fail */
        sgimc = (struct sgimc_regs *)
                ioremap(SGIMC_BASE, sizeof(struct sgimc_regs));

        printk(KERN_INFO "MC: SGI memory controller Revision %d\n",
               (int) sgimc->systemid & SGIMC_SYSID_MASKREV);

        /* Place the MC into a known state.  This must be done before
         * interrupts are first enabled etc.
         */

        /* Step 0: Make sure we turn off the watchdog in case it's
         *         still running (which might be the case after a
         *         soft reboot).
         */
        tmp = sgimc->cpuctrl0;
        tmp &= ~SGIMC_CCTRL0_WDOG;
        sgimc->cpuctrl0 = tmp;

        /* Step 1: The CPU/GIO error status registers will not latch
         *         up a new error status until the register has been
         *         cleared by the cpu.  These status registers are
         *         cleared by writing any value to them.
         */
        sgimc->cstat = sgimc->gstat = 0;

        /* Step 2: Enable all parity checking in cpu control register
         *         zero.
         */
        /* don't touch parity settings for IP28 */
#ifndef CONFIG_SGI_IP28
        tmp = sgimc->cpuctrl0;
        tmp |= (SGIMC_CCTRL0_EPERRGIO | SGIMC_CCTRL0_EPERRMEM |
                SGIMC_CCTRL0_R4KNOCHKPARR);
#endif
        sgimc->cpuctrl0 = tmp;

        /* Step 3: Setup the MC write buffer depth, this is controlled
         *         in cpu control register 1 in the lower 4 bits.
         */
        tmp = sgimc->cpuctrl1;
        tmp &= ~0xf;
        tmp |= 0xd;
        sgimc->cpuctrl1 = tmp;

        /* Step 4: Initialize the RPSS divider register to run as fast
         *         as it can correctly operate.  The register is laid
         *         out as follows:
         *
         *         ----------------------------------------
         *         |  RESERVED  |   INCREMENT   | DIVIDER |
         *         ----------------------------------------
         *          31        16 15            8 7       0
         *
         *         DIVIDER determines how often a 'tick' happens,
         *         INCREMENT determines by how the RPSS increment
         *         registers value increases at each 'tick'. Thus,
         *         for IP22 we get INCREMENT=1, DIVIDER=1 == 0x101
         */
        sgimc->divider = 0x101;

        /* Step 5: Initialize GIO64 arbitrator configuration register.
         *
         * NOTE: HPC init code in sgihpc_init() must run before us because
         *       we need to know Guiness vs. FullHouse and the board
         *       revision on this machine. You have been warned.
         */

        /* First the basic invariants across all GIO64 implementations. */
        tmp = SGIMC_GIOPAR_HPC64;       /* All 1st HPC's interface at 64bits */
        tmp |= SGIMC_GIOPAR_ONEBUS;     /* Only one physical GIO bus exists */

        if (ip22_is_fullhouse()) {
                /* Fullhouse specific settings. */
                if (SGIOC_SYSID_BOARDREV(sgioc->sysid) < 2) {
                        tmp |= SGIMC_GIOPAR_HPC264;     /* 2nd HPC at 64bits */
                        tmp |= SGIMC_GIOPAR_PLINEEXP0;  /* exp0 pipelines */
                        tmp |= SGIMC_GIOPAR_MASTEREXP1; /* exp1 masters */
                        tmp |= SGIMC_GIOPAR_RTIMEEXP0;  /* exp0 is realtime */
                } else {
                        tmp |= SGIMC_GIOPAR_HPC264;     /* 2nd HPC 64bits */
                        tmp |= SGIMC_GIOPAR_PLINEEXP0;  /* exp[01] pipelined */
                        tmp |= SGIMC_GIOPAR_PLINEEXP1;
                        tmp |= SGIMC_GIOPAR_MASTEREISA; /* EISA masters */
                        tmp |= SGIMC_GIOPAR_GFX64;      /* GFX at 64 bits */
                }
        } else {
                /* Guiness specific settings. */
                tmp |= SGIMC_GIOPAR_EISA64;     /* MC talks to EISA at 64bits */
                tmp |= SGIMC_GIOPAR_MASTEREISA; /* EISA bus can act as master */
        }
        sgimc->giopar = tmp;    /* poof */

        probe_memory();
}

void __init prom_meminit(void) {}
void __init prom_free_prom_memory(void)
{
#ifdef CONFIG_SGI_IP28
        u32 mconfig1;
        unsigned long flags;
        spinlock_t lock;

        /*
         * because ARCS accesses memory uncached we wait until ARCS
         * isn't needed any longer, before we switch from slow to
         * normal mode
         */
        spin_lock_irqsave(&lock, flags);
        mconfig1 = sgimc->mconfig1;
        /* map ECC register */
        sgimc->mconfig1 = (mconfig1 & 0xffff0000) | 0x2060;
        iob();
        /* switch to normal mode */
        *(unsigned long *)PHYS_TO_XKSEG_UNCACHED(0x60000000) = 0;
        iob();
        /* reduce WR_COL */
        sgimc->cmacc = (sgimc->cmacc & ~0xf) | 4;
        iob();
        /* restore old config */
        sgimc->mconfig1 = mconfig1;
        iob();
        spin_unlock_irqrestore(&lock, flags);
#endif
}