/*
 *    Copyright (c) 2000 Mike Corrigan <mikejc@us.ibm.com>
 *    Copyright (c) 1999-2000 Grant Erickson <grant@lcse.umn.edu>
 *
 *    Description:
 *      Architecture- / platform-specific boot-time initialization code for
 *      the IBM iSeries LPAR.  Adapted from original code by Grant Erickson and
 *      code by Gary Thomas, Cort Dougan <cort@fsmlabs.com>, and Dan Malek
 *      <dan@net4x.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 of the License, or (at your option) any later version.
 */

#undef DEBUG

#include <linux/init.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/seq_file.h>
#include <linux/kdev_t.h>
#include <linux/kexec.h>
#include <linux/major.h>
#include <linux/root_dev.h>
#include <linux/kernel.h>
#include <linux/hrtimer.h>
#include <linux/tick.h>

#include <asm/processor.h>
#include <asm/machdep.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
#include <asm/cputable.h>
#include <asm/sections.h>
#include <asm/iommu.h>
#include <asm/firmware.h>
#include <asm/system.h>
#include <asm/time.h>
#include <asm/paca.h>
#include <asm/cache.h>
#include <asm/abs_addr.h>
#include <asm/iseries/hv_lp_config.h>
#include <asm/iseries/hv_call_event.h>
#include <asm/iseries/hv_call_xm.h>
#include <asm/iseries/it_lp_queue.h>
#include <asm/iseries/mf.h>
#include <asm/iseries/hv_lp_event.h>
#include <asm/iseries/lpar_map.h>
#include <asm/udbg.h>
#include <asm/irq.h>

#include "naca.h"
#include "setup.h"
#include "irq.h"
#include "vpd_areas.h"
#include "processor_vpd.h"
#include "it_lp_naca.h"
#include "main_store.h"
#include "call_sm.h"
#include "call_hpt.h"
#include "pci.h"

#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif

/* Function Prototypes */
static unsigned long build_iSeries_Memory_Map(void);
static void iseries_shared_idle(void);
static void iseries_dedicated_idle(void);


struct MemoryBlock {
        unsigned long absStart;
        unsigned long absEnd;
        unsigned long logicalStart;
        unsigned long logicalEnd;
};

/*
 * Process the main store vpd to determine where the holes in memory are
 * and return the number of physical blocks and fill in the array of
 * block data.
 */
static unsigned long iSeries_process_Condor_mainstore_vpd(
                struct MemoryBlock *mb_array, unsigned long max_entries)
{
        unsigned long holeFirstChunk, holeSizeChunks;
        unsigned long numMemoryBlocks = 1;
        struct IoHriMainStoreSegment4 *msVpd =
                (struct IoHriMainStoreSegment4 *)xMsVpd;
        unsigned long holeStart = msVpd->nonInterleavedBlocksStartAdr;
        unsigned long holeEnd = msVpd->nonInterleavedBlocksEndAdr;
        unsigned long holeSize = holeEnd - holeStart;

        printk("Mainstore_VPD: Condor\n");
        /*
         * Determine if absolute memory has any
         * holes so that we can interpret the
         * access map we get back from the hypervisor
         * correctly.
         */
        mb_array[0].logicalStart = 0;
        mb_array[0].logicalEnd = 0x100000000UL;
        mb_array[0].absStart = 0;
        mb_array[0].absEnd = 0x100000000UL;

        if (holeSize) {
                numMemoryBlocks = 2;
                holeStart = holeStart & 0x000fffffffffffffUL;
                holeStart = addr_to_chunk(holeStart);
                holeFirstChunk = holeStart;
                holeSize = addr_to_chunk(holeSize);
                holeSizeChunks = holeSize;
                printk( "Main store hole: start chunk = %0lx, size = %0lx chunks\n",
                                holeFirstChunk, holeSizeChunks );
                mb_array[0].logicalEnd = holeFirstChunk;
                mb_array[0].absEnd = holeFirstChunk;
                mb_array[1].logicalStart = holeFirstChunk;
                mb_array[1].logicalEnd = 0x100000000UL - holeSizeChunks;
                mb_array[1].absStart = holeFirstChunk + holeSizeChunks;
                mb_array[1].absEnd = 0x100000000UL;
        }
        return numMemoryBlocks;
}

#define MaxSegmentAreas                 32
#define MaxSegmentAdrRangeBlocks        128
#define MaxAreaRangeBlocks              4

static unsigned long iSeries_process_Regatta_mainstore_vpd(
                struct MemoryBlock *mb_array, unsigned long max_entries)
{
        struct IoHriMainStoreSegment5 *msVpdP =
                (struct IoHriMainStoreSegment5 *)xMsVpd;
        unsigned long numSegmentBlocks = 0;
        u32 existsBits = msVpdP->msAreaExists;
        unsigned long area_num;

        printk("Mainstore_VPD: Regatta\n");

        for (area_num = 0; area_num < MaxSegmentAreas; ++area_num ) {
                unsigned long numAreaBlocks;
                struct IoHriMainStoreArea4 *currentArea;

                if (existsBits & 0x80000000) {
                        unsigned long block_num;

                        currentArea = &msVpdP->msAreaArray[area_num];
                        numAreaBlocks = currentArea->numAdrRangeBlocks;
                        printk("ms_vpd: processing area %2ld  blocks=%ld",
                                        area_num, numAreaBlocks);
                        for (block_num = 0; block_num < numAreaBlocks;
                                        ++block_num ) {
                                /* Process an address range block */
                                struct MemoryBlock tempBlock;
                                unsigned long i;

                                tempBlock.absStart =
                                        (unsigned long)currentArea->xAdrRangeBlock[block_num].blockStart;
                                tempBlock.absEnd =
                                        (unsigned long)currentArea->xAdrRangeBlock[block_num].blockEnd;
                                tempBlock.logicalStart = 0;
                                tempBlock.logicalEnd   = 0;
                                printk("\n          block %ld absStart=%016lx absEnd=%016lx",
                                                block_num, tempBlock.absStart,
                                                tempBlock.absEnd);

                                for (i = 0; i < numSegmentBlocks; ++i) {
                                        if (mb_array[i].absStart ==
                                                        tempBlock.absStart)
                                                break;
                                }
                                if (i == numSegmentBlocks) {
                                        if (numSegmentBlocks == max_entries)
                                                panic("iSeries_process_mainstore_vpd: too many memory blocks");
                                        mb_array[numSegmentBlocks] = tempBlock;
                                        ++numSegmentBlocks;
                                } else
                                        printk(" (duplicate)");
                        }
                        printk("\n");
                }
                existsBits <<= 1;
        }
        /* Now sort the blocks found into ascending sequence */
        if (numSegmentBlocks > 1) {
                unsigned long m, n;

                for (m = 0; m < numSegmentBlocks - 1; ++m) {
                        for (n = numSegmentBlocks - 1; m < n; --n) {
                                if (mb_array[n].absStart <
                                                mb_array[n-1].absStart) {
                                        struct MemoryBlock tempBlock;

                                        tempBlock = mb_array[n];
                                        mb_array[n] = mb_array[n-1];
                                        mb_array[n-1] = tempBlock;
                                }
                        }
                }
        }
        /*
         * Assign "logical" addresses to each block.  These
         * addresses correspond to the hypervisor "bitmap" space.
         * Convert all addresses into units of 256K chunks.
         */
        {
        unsigned long i, nextBitmapAddress;

        printk("ms_vpd: %ld sorted memory blocks\n", numSegmentBlocks);
        nextBitmapAddress = 0;
        for (i = 0; i < numSegmentBlocks; ++i) {
                unsigned long length = mb_array[i].absEnd -
                        mb_array[i].absStart;

                mb_array[i].logicalStart = nextBitmapAddress;
                mb_array[i].logicalEnd = nextBitmapAddress + length;
                nextBitmapAddress += length;
                printk("          Bitmap range: %016lx - %016lx\n"
                                "        Absolute range: %016lx - %016lx\n",
                                mb_array[i].logicalStart,
                                mb_array[i].logicalEnd,
                                mb_array[i].absStart, mb_array[i].absEnd);
                mb_array[i].absStart = addr_to_chunk(mb_array[i].absStart &
                                0x000fffffffffffffUL);
                mb_array[i].absEnd = addr_to_chunk(mb_array[i].absEnd &
                                0x000fffffffffffffUL);
                mb_array[i].logicalStart =
                        addr_to_chunk(mb_array[i].logicalStart);
                mb_array[i].logicalEnd = addr_to_chunk(mb_array[i].logicalEnd);
        }
        }

        return numSegmentBlocks;
}

static unsigned long iSeries_process_mainstore_vpd(struct MemoryBlock *mb_array,
                unsigned long max_entries)
{
        unsigned long i;
        unsigned long mem_blocks = 0;

        if (cpu_has_feature(CPU_FTR_SLB))
                mem_blocks = iSeries_process_Regatta_mainstore_vpd(mb_array,
                                max_entries);
        else
                mem_blocks = iSeries_process_Condor_mainstore_vpd(mb_array,
                                max_entries);

        printk("Mainstore_VPD: numMemoryBlocks = %ld \n", mem_blocks);
        for (i = 0; i < mem_blocks; ++i) {
                printk("Mainstore_VPD: block %3ld logical chunks %016lx - %016lx\n"
                       "                             abs chunks %016lx - %016lx\n",
                        i, mb_array[i].logicalStart, mb_array[i].logicalEnd,
                        mb_array[i].absStart, mb_array[i].absEnd);
        }
        return mem_blocks;
}

static void __init iSeries_get_cmdline(void)
{
        char *p, *q;

        /* copy the command line parameter from the primary VSP  */
        HvCallEvent_dmaToSp(cmd_line, 2 * 64* 1024, 256,
                        HvLpDma_Direction_RemoteToLocal);

        p = cmd_line;
        q = cmd_line + 255;
        while(p < q) {
                if (!*p || *p == '\n')
                        break;
                ++p;
        }
        *p = 0;
}

static void __init iSeries_init_early(void)
{
        DBG(" -> iSeries_init_early()\n");

        /* Snapshot the timebase, for use in later recalibration */
        iSeries_time_init_early();

        /*
         * Initialize the DMA/TCE management
         */
        iommu_init_early_iSeries();

        /* Initialize machine-dependency vectors */
#ifdef CONFIG_SMP
        smp_init_iSeries();
#endif

        /* Associate Lp Event Queue 0 with processor 0 */
        HvCallEvent_setLpEventQueueInterruptProc(0, 0);

        mf_init();

        DBG(" <- iSeries_init_early()\n");
}

struct mschunks_map mschunks_map = {
        /* XXX We don't use these, but Piranha might need them. */
        .chunk_size  = MSCHUNKS_CHUNK_SIZE,
        .chunk_shift = MSCHUNKS_CHUNK_SHIFT,
        .chunk_mask  = MSCHUNKS_OFFSET_MASK,
};
EXPORT_SYMBOL(mschunks_map);

static void mschunks_alloc(unsigned long num_chunks)
{
        klimit = _ALIGN(klimit, sizeof(u32));
        mschunks_map.mapping = (u32 *)klimit;
        klimit += num_chunks * sizeof(u32);
        mschunks_map.num_chunks = num_chunks;
}

/*
 * The iSeries may have very large memories ( > 128 GB ) and a partition
 * may get memory in "chunks" that may be anywhere in the 2**52 real
 * address space.  The chunks are 256K in size.  To map this to the
 * memory model Linux expects, the AS/400 specific code builds a
 * translation table to translate what Linux thinks are "physical"
 * addresses to the actual real addresses.  This allows us to make
 * it appear to Linux that we have contiguous memory starting at
 * physical address zero while in fact this could be far from the truth.
 * To avoid confusion, I'll let the words physical and/or real address
 * apply to the Linux addresses while I'll use "absolute address" to
 * refer to the actual hardware real address.
 *
 * build_iSeries_Memory_Map gets information from the Hypervisor and
 * looks at the Main Store VPD to determine the absolute addresses
 * of the memory that has been assigned to our partition and builds
 * a table used to translate Linux's physical addresses to these
 * absolute addresses.  Absolute addresses are needed when
 * communicating with the hypervisor (e.g. to build HPT entries)
 *
 * Returns the physical memory size
 */

static unsigned long __init build_iSeries_Memory_Map(void)
{
        u32 loadAreaFirstChunk, loadAreaLastChunk, loadAreaSize;
        u32 nextPhysChunk;
        u32 hptFirstChunk, hptLastChunk, hptSizeChunks, hptSizePages;
        u32 totalChunks,moreChunks;
        u32 currChunk, thisChunk, absChunk;
        u32 currDword;
        u32 chunkBit;
        u64 map;
        struct MemoryBlock mb[32];
        unsigned long numMemoryBlocks, curBlock;

        /* Chunk size on iSeries is 256K bytes */
        totalChunks = (u32)HvLpConfig_getMsChunks();
        mschunks_alloc(totalChunks);

        /*
         * Get absolute address of our load area
         * and map it to physical address 0
         * This guarantees that the loadarea ends up at physical 0
         * otherwise, it might not be returned by PLIC as the first
         * chunks
         */

        loadAreaFirstChunk = (u32)addr_to_chunk(itLpNaca.xLoadAreaAddr);
        loadAreaSize =  itLpNaca.xLoadAreaChunks;

        /*
         * Only add the pages already mapped here.
         * Otherwise we might add the hpt pages
         * The rest of the pages of the load area
         * aren't in the HPT yet and can still
         * be assigned an arbitrary physical address
         */
        if ((loadAreaSize * 64) > HvPagesToMap)
                loadAreaSize = HvPagesToMap / 64;

        loadAreaLastChunk = loadAreaFirstChunk + loadAreaSize - 1;

        /*
         * TODO Do we need to do something if the HPT is in the 64MB load area?
         * This would be required if the itLpNaca.xLoadAreaChunks includes
         * the HPT size
         */

        printk("Mapping load area - physical addr = 0000000000000000\n"
                "                    absolute addr = %016lx\n",
                chunk_to_addr(loadAreaFirstChunk));
        printk("Load area size %dK\n", loadAreaSize * 256);

        for (nextPhysChunk = 0; nextPhysChunk < loadAreaSize; ++nextPhysChunk)
                mschunks_map.mapping[nextPhysChunk] =
                        loadAreaFirstChunk + nextPhysChunk;

        /*
         * Get absolute address of our HPT and remember it so
         * we won't map it to any physical address
         */
        hptFirstChunk = (u32)addr_to_chunk(HvCallHpt_getHptAddress());
        hptSizePages = (u32)HvCallHpt_getHptPages();
        hptSizeChunks = hptSizePages >>
                (MSCHUNKS_CHUNK_SHIFT - HW_PAGE_SHIFT);
        hptLastChunk = hptFirstChunk + hptSizeChunks - 1;

        printk("HPT absolute addr = %016lx, size = %dK\n",
                        chunk_to_addr(hptFirstChunk), hptSizeChunks * 256);

        /*
         * Determine if absolute memory has any
         * holes so that we can interpret the
         * access map we get back from the hypervisor
         * correctly.
         */
        numMemoryBlocks = iSeries_process_mainstore_vpd(mb, 32);

        /*
         * Process the main store access map from the hypervisor
         * to build up our physical -> absolute translation table
         */
        curBlock = 0;
        currChunk = 0;
        currDword = 0;
        moreChunks = totalChunks;

        while (moreChunks) {
                map = HvCallSm_get64BitsOfAccessMap(itLpNaca.xLpIndex,
                                currDword);
                thisChunk = currChunk;
                while (map) {
                        chunkBit = map >> 63;
                        map <<= 1;
                        if (chunkBit) {
                                --moreChunks;
                                while (thisChunk >= mb[curBlock].logicalEnd) {
                                        ++curBlock;
                                        if (curBlock >= numMemoryBlocks)
                                                panic("out of memory blocks");
                                }
                                if (thisChunk < mb[curBlock].logicalStart)
                                        panic("memory block error");

                                absChunk = mb[curBlock].absStart +
                                        (thisChunk - mb[curBlock].logicalStart);
                                if (((absChunk < hptFirstChunk) ||
                                     (absChunk > hptLastChunk)) &&
                                    ((absChunk < loadAreaFirstChunk) ||
                                     (absChunk > loadAreaLastChunk))) {
                                        mschunks_map.mapping[nextPhysChunk] =
                                                absChunk;
                                        ++nextPhysChunk;
                                }
                        }
                        ++thisChunk;
                }
                ++currDword;
                currChunk += 64;
        }

        /*
         * main store size (in chunks) is
         *   totalChunks - hptSizeChunks
         * which should be equal to
         *   nextPhysChunk
         */
        return chunk_to_addr(nextPhysChunk);
}

/*
 * Document me.
 */
static void __init iSeries_setup_arch(void)
{
        if (get_lppaca()->shared_proc) {
                ppc_md.idle_loop = iseries_shared_idle;
                printk(KERN_DEBUG "Using shared processor idle loop\n");
        } else {
                ppc_md.idle_loop = iseries_dedicated_idle;
                printk(KERN_DEBUG "Using dedicated idle loop\n");
        }

        /* Setup the Lp Event Queue */
        setup_hvlpevent_queue();

        printk("Max  logical processors = %d\n",
                        itVpdAreas.xSlicMaxLogicalProcs);
        printk("Max physical processors = %d\n",
                        itVpdAreas.xSlicMaxPhysicalProcs);

        iSeries_pcibios_init();
}

static void iSeries_show_cpuinfo(struct seq_file *m)
{
        seq_printf(m, "machine\t\t: 64-bit iSeries Logical Partition\n");
}

static void __init iSeries_progress(char * st, unsigned short code)
{
        printk("Progress: [%04x] - %s\n", (unsigned)code, st);
        mf_display_progress(code);
}

static void __init iSeries_fixup_klimit(void)
{
        /*
         * Change klimit to take into account any ram disk
         * that may be included
         */
        if (naca.xRamDisk)
                klimit = KERNELBASE + (u64)naca.xRamDisk +
                        (naca.xRamDiskSize * HW_PAGE_SIZE);
}

static int __init iSeries_src_init(void)
{
        /* clear the progress line */
        if (firmware_has_feature(FW_FEATURE_ISERIES))
                ppc_md.progress(" ", 0xffff);
        return 0;
}

late_initcall(iSeries_src_init);

static inline void process_iSeries_events(void)
{
        asm volatile ("li 0,0x5555; sc" : : : "r0", "r3");
}

static void yield_shared_processor(void)
{
        unsigned long tb;

        HvCall_setEnabledInterrupts(HvCall_MaskIPI |
                                    HvCall_MaskLpEvent |
                                    HvCall_MaskLpProd |
                                    HvCall_MaskTimeout);

        tb = get_tb();
        /* Compute future tb value when yield should expire */
        HvCall_yieldProcessor(HvCall_YieldTimed, tb+tb_ticks_per_jiffy);

        /*
         * The decrementer stops during the yield.  Force a fake decrementer
         * here and let the timer_interrupt code sort out the actual time.
         */
        get_lppaca()->int_dword.fields.decr_int = 1;
        ppc64_runlatch_on();
        process_iSeries_events();
}

static void iseries_shared_idle(void)
{
        while (1) {
                tick_nohz_stop_sched_tick(1);
                while (!need_resched() && !hvlpevent_is_pending()) {
                        local_irq_disable();
                        ppc64_runlatch_off();

                        /* Recheck with irqs off */
                        if (!need_resched() && !hvlpevent_is_pending())
                                yield_shared_processor();

                        HMT_medium();
                        local_irq_enable();
                }

                ppc64_runlatch_on();
                tick_nohz_restart_sched_tick();

                if (hvlpevent_is_pending())
                        process_iSeries_events();

                preempt_enable_no_resched();
                schedule();
                preempt_disable();
        }
}

static void iseries_dedicated_idle(void)
{
        set_thread_flag(TIF_POLLING_NRFLAG);

        while (1) {
                tick_nohz_stop_sched_tick(1);
                if (!need_resched()) {
                        while (!need_resched()) {
                                ppc64_runlatch_off();
                                HMT_low();

                                if (hvlpevent_is_pending()) {
                                        HMT_medium();
                                        ppc64_runlatch_on();
                                        process_iSeries_events();
                                }
                        }

                        HMT_medium();
                }

                ppc64_runlatch_on();
                tick_nohz_restart_sched_tick();
                preempt_enable_no_resched();
                schedule();
                preempt_disable();
        }
}

static void __iomem *iseries_ioremap(phys_addr_t address, unsigned long size,
                                     unsigned long flags, void *caller)
{
        return (void __iomem *)address;
}

static void iseries_iounmap(volatile void __iomem *token)
{
}

static int __init iseries_probe(void)
{
        unsigned long root = of_get_flat_dt_root();
        if (!of_flat_dt_is_compatible(root, "IBM,iSeries"))
                return 0;

        hpte_init_iSeries();
        /* iSeries does not support 16M pages */
        cur_cpu_spec->cpu_features &= ~CPU_FTR_16M_PAGE;

        return 1;
}

#ifdef CONFIG_KEXEC
static int iseries_kexec_prepare(struct kimage *image)
{
        return -ENOSYS;
}
#endif

define_machine(iseries) {
        .name                   = "iSeries",
        .setup_arch             = iSeries_setup_arch,
        .show_cpuinfo           = iSeries_show_cpuinfo,
        .init_IRQ               = iSeries_init_IRQ,
        .get_irq                = iSeries_get_irq,
        .init_early             = iSeries_init_early,
        .pcibios_fixup          = iSeries_pci_final_fixup,
        .pcibios_fixup_resources= iSeries_pcibios_fixup_resources,
        .restart                = mf_reboot,
        .power_off              = mf_power_off,
        .halt                   = mf_power_off,
        .get_boot_time          = iSeries_get_boot_time,
        .set_rtc_time           = iSeries_set_rtc_time,
        .get_rtc_time           = iSeries_get_rtc_time,
        .calibrate_decr         = generic_calibrate_decr,
        .progress               = iSeries_progress,
        .probe                  = iseries_probe,
        .ioremap                = iseries_ioremap,
        .iounmap                = iseries_iounmap,
#ifdef CONFIG_KEXEC
        .machine_kexec_prepare  = iseries_kexec_prepare,
#endif
        /* XXX Implement enable_pmcs for iSeries */
};

void * __init iSeries_early_setup(void)
{
        unsigned long phys_mem_size;

        /* Identify CPU type. This is done again by the common code later
         * on but calling this function multiple times is fine.
         */
        identify_cpu(0, mfspr(SPRN_PVR));

        powerpc_firmware_features |= FW_FEATURE_ISERIES;
        powerpc_firmware_features |= FW_FEATURE_LPAR;

        iSeries_fixup_klimit();

        /*
         * Initialize the table which translate Linux physical addresses to
         * AS/400 absolute addresses
         */
        phys_mem_size = build_iSeries_Memory_Map();

        iSeries_get_cmdline();

        return (void *) __pa(build_flat_dt(phys_mem_size));
}

static void hvputc(char c)
{
        if (c == '\n')
                hvputc('\r');

        HvCall_writeLogBuffer(&c, 1);
}

void __init udbg_init_iseries(void)
{
        udbg_putc = hvputc;
}