/*
 * arch/mips/jazz/jazzdma.c
 *
 * Mips Jazz DMA controller support
 * Copyright (C) 1995, 1996 by Andreas Busse
 *
 * NOTE: Some of the argument checking could be removed when
 * things have settled down. Also, instead of returning 0xffffffff
 * on failure of vdma_alloc() one could leave page #0 unused
 * and return the more usual NULL pointer as logical address.
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <asm/mipsregs.h>
#include <asm/mipsconfig.h>
#include <asm/jazz.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/dma.h>
#include <asm/jazzdma.h>
#include <asm/pgtable.h>

/*
 * Set this to one to enable additional vdma debug code.
 */
#define CONF_DEBUG_VDMA 0

static unsigned long vdma_pagetable_start = 0;
static unsigned long vdma_pagetable_end = 0;

/*
 * Debug stuff
 */
#define vdma_debug     ((CONF_DEBUG_VDMA) ? debuglvl : 0)

static int debuglvl = 3;

/*
 * Initialize the pagetable with a one-to-one mapping of
 * the first 16 Mbytes of main memory and declare all
 * entries to be unused. Using this method will at least
 * allow some early device driver operations to work.
 */
static inline void vdma_pgtbl_init(void)
{
    int i;
    unsigned long paddr = 0;
    VDMA_PGTBL_ENTRY *pgtbl = (VDMA_PGTBL_ENTRY *)vdma_pagetable_start;
  
    for (i=0; i<VDMA_PGTBL_ENTRIES; i++)
    {
        pgtbl[i].frame = paddr;
        pgtbl[i].owner = VDMA_PAGE_EMPTY;
        paddr += VDMA_PAGESIZE;
    }
}

/*
 * Initialize the Jazz R4030 dma controller
 */
unsigned long vdma_init(unsigned long memory_start, unsigned long memory_end)
{
    /*
     * Allocate 32k of memory for DMA page tables.
     * This needs to be page aligned and should be
     * uncached to avoid cache flushing after every
     * update.
     */
    vdma_pagetable_start = KSEG1ADDR((memory_start + 4095) & ~4095);
    vdma_pagetable_end = vdma_pagetable_start + VDMA_PGTBL_SIZE;
    flush_cache_all();

    /*
     * Clear the R4030 translation table
     */
    vdma_pgtbl_init();

    r4030_write_reg32(JAZZ_R4030_TRSTBL_BASE,PHYSADDR(vdma_pagetable_start));
    r4030_write_reg32(JAZZ_R4030_TRSTBL_LIM,VDMA_PGTBL_SIZE);
    r4030_write_reg32(JAZZ_R4030_TRSTBL_INV,0);

    printk("VDMA: R4030 DMA pagetables initialized.\n");

    return KSEG0ADDR(vdma_pagetable_end);
}

/*
 * Allocate DMA pagetables using a simple first-fit algorithm
 */
unsigned long vdma_alloc(unsigned long paddr, unsigned long size)
{
    VDMA_PGTBL_ENTRY *entry = (VDMA_PGTBL_ENTRY *)vdma_pagetable_start;
    int first;
    int last;
    int pages;
    unsigned int frame;
    unsigned long laddr;
    int i;

    /* check arguments */
  
    if (paddr > 0x1fffffff)
    {
        if (vdma_debug)
            printk("vdma_alloc: Invalid physical address: %08lx\n",paddr);
        return VDMA_ERROR;	/* invalid physical address */
    }
    if (size > 0x400000 || size == 0)
    {
        if (vdma_debug)
            printk("vdma_alloc: Invalid size: %08lx\n",size);
        return VDMA_ERROR;	/* invalid physical address */
    }
  
    /*
     * Find free chunk
     */
    pages = (size + 4095) >> 12; /* no. of pages to allocate */
    first = 0;
    while (1)
    {
        while (entry[first].owner != VDMA_PAGE_EMPTY &&
               first < VDMA_PGTBL_ENTRIES)
            first++;
        if (first+pages > VDMA_PGTBL_ENTRIES) /* nothing free */
            return VDMA_ERROR;

        last = first+1;
        while (entry[last].owner == VDMA_PAGE_EMPTY && last-first < pages)
            last++;
    
        if (last-first == pages)
            break;			/* found */
    }
  
    /*
     * Mark pages as allocated
     */
    laddr = (first << 12) + (paddr & (VDMA_PAGESIZE-1));
    frame = paddr & ~(VDMA_PAGESIZE-1);
  
    for (i=first; i<last; i++)
    {
        entry[i].frame = frame;
        entry[i].owner = laddr;
        frame += VDMA_PAGESIZE;
    }

    /*
     * Update translation table and return logical start address
     */
    r4030_write_reg32(JAZZ_R4030_TRSTBL_INV,0);

    if (vdma_debug > 1)
        printk("vdma_alloc: Allocated %d pages starting from %08lx\n",
               pages,laddr);

    if (vdma_debug > 2)
    {
        printk("LADDR: ");
        for (i=first; i<last; i++)
            printk("%08x ",i<<12);
        printk("\nPADDR: ");
        for (i=first; i<last; i++)
            printk("%08x ",entry[i].frame);
        printk("\nOWNER: ");
        for (i=first; i<last; i++)
            printk("%08x ",entry[i].owner);
        printk("\n");
    }
  
    return laddr;
}

/*
 * Free previously allocated dma translation pages
 * Note that this does NOT change the translation table,
 * it just marks the free'd pages as unused!
 */
int vdma_free(unsigned long laddr)
{
    VDMA_PGTBL_ENTRY *pgtbl = (VDMA_PGTBL_ENTRY *)vdma_pagetable_start;
    int i;

    i = laddr >> 12;

    if (pgtbl[i].owner != laddr)
    {
        printk("vdma_free: trying to free other's dma pages, laddr=%8lx\n",
               laddr);
        return -1;
    }
  
    while (pgtbl[i].owner == laddr && i < VDMA_PGTBL_ENTRIES)
    {
        pgtbl[i].owner = VDMA_PAGE_EMPTY;
        i++;
    }
  
    if (vdma_debug > 1)
        printk("vdma_free: freed %ld pages starting from %08lx\n",
               i-(laddr>>12),laddr);
  
    return 0;
}

/*
 * Map certain page(s) to another physical address.
 * Caller must have allocated the page(s) before.
 */
int vdma_remap(unsigned long laddr, unsigned long paddr, unsigned long size)
{
    VDMA_PGTBL_ENTRY *pgtbl = (VDMA_PGTBL_ENTRY *)vdma_pagetable_start;
    int first, pages, npages;

    if (laddr > 0xffffff)
    {
        if (vdma_debug)
            printk("vdma_map: Invalid logical address: %08lx\n",laddr);
        return -EINVAL;		/* invalid logical address */
    }
    if (paddr > 0x1fffffff)
    {
        if (vdma_debug)
            printk("vdma_map: Invalid physical address: %08lx\n",paddr);
        return -EINVAL;		/* invalid physical address */
    }
  
    npages = pages = (((paddr & (VDMA_PAGESIZE-1)) + size) >> 12) + 1;
    first = laddr >> 12;
    if (vdma_debug)
        printk("vdma_remap: first=%x, pages=%x\n",first,pages);
    if (first+pages > VDMA_PGTBL_ENTRIES)
    {
        if (vdma_debug)
            printk("vdma_alloc: Invalid size: %08lx\n",size);
        return -EINVAL;
    }

    paddr &= ~(VDMA_PAGESIZE-1);
    while (pages > 0 && first < VDMA_PGTBL_ENTRIES)
    {
        if (pgtbl[first].owner != laddr)
        {
            if (vdma_debug)
                printk("Trying to remap other's pages.\n");
            return -EPERM;		/* not owner */
        }
        pgtbl[first].frame = paddr;
        paddr += VDMA_PAGESIZE;
        first++;
        pages--;
    }

    /*
     * Update translation table
     */
    r4030_write_reg32(JAZZ_R4030_TRSTBL_INV,0);
  
    if (vdma_debug > 2)
    {
        int i;
        pages = (((paddr & (VDMA_PAGESIZE-1)) + size) >> 12) + 1;
        first = laddr >> 12;
        printk("LADDR: ");
        for (i=first; i<first+pages; i++)
            printk("%08x ",i<<12);
        printk("\nPADDR: ");
        for (i=first; i<first+pages; i++)
            printk("%08x ",pgtbl[i].frame);
        printk("\nOWNER: ");
        for (i=first; i<first+pages; i++)
            printk("%08x ",pgtbl[i].owner);
        printk("\n");
    }
      
    return 0;
}

/*
 * Translate a physical address to a logical address.
 * This will return the logical address of the first
 * match.
 */
unsigned long vdma_phys2log(unsigned long paddr)
{
    int i;
    int frame;
    VDMA_PGTBL_ENTRY *pgtbl = (VDMA_PGTBL_ENTRY *)vdma_pagetable_start;

    frame = paddr & ~(VDMA_PAGESIZE-1);

    for (i=0; i<VDMA_PGTBL_ENTRIES; i++)
    {
        if (pgtbl[i].frame == frame)
            break;
    }

    if (i == VDMA_PGTBL_ENTRIES)
        return ~0UL;

    return (i<<12) + (paddr & (VDMA_PAGESIZE-1));
}

/*
 * Translate a logical DMA address to a physical address
 */
unsigned long vdma_log2phys(unsigned long laddr)
{
    VDMA_PGTBL_ENTRY *pgtbl = (VDMA_PGTBL_ENTRY *)vdma_pagetable_start;

    return pgtbl[laddr >> 12].frame + (laddr & (VDMA_PAGESIZE-1));
}
  
/*
 * Print DMA statistics
 */
void vdma_stats(void)
{
    int i;
  
    printk("vdma_stats: CONFIG: %08x\n",
           r4030_read_reg32(JAZZ_R4030_CONFIG));
    printk("R4030 translation table base: %08x\n",
           r4030_read_reg32(JAZZ_R4030_TRSTBL_BASE));
    printk("R4030 translation table limit: %08x\n",
           r4030_read_reg32(JAZZ_R4030_TRSTBL_LIM));
    printk("vdma_stats: INV_ADDR: %08x\n",
           r4030_read_reg32(JAZZ_R4030_INV_ADDR));
    printk("vdma_stats: R_FAIL_ADDR: %08x\n",
           r4030_read_reg32(JAZZ_R4030_R_FAIL_ADDR));
    printk("vdma_stats: M_FAIL_ADDR: %08x\n",
           r4030_read_reg32(JAZZ_R4030_M_FAIL_ADDR));
    printk("vdma_stats: IRQ_SOURCE: %08x\n",
           r4030_read_reg32(JAZZ_R4030_IRQ_SOURCE));
    printk("vdma_stats: I386_ERROR: %08x\n",
           r4030_read_reg32(JAZZ_R4030_I386_ERROR));
    printk("vdma_chnl_modes:   ");
    for (i=0; i<8; i++)
        printk("%04x ",
               (unsigned)r4030_read_reg32(JAZZ_R4030_CHNL_MODE+(i<<5)));
    printk("\n");
    printk("vdma_chnl_enables: ");
    for (i=0; i<8; i++)
        printk("%04x ",
               (unsigned)r4030_read_reg32(JAZZ_R4030_CHNL_ENABLE+(i<<5)));
    printk("\n");
}

/*
 * DMA transfer functions
 */

/*
 * Enable a DMA channel. Also clear any error conditions.
 */
void vdma_enable(int channel)
{
    int status;
  
    if (vdma_debug)
        printk("vdma_enable: channel %d\n",channel);
  
    /*
     * Check error conditions first
     */
    status = r4030_read_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5));
    if (status & 0x400)
        printk("VDMA: Channel %d: Address error!\n",channel);
    if (status & 0x200)
        printk("VDMA: Channel %d: Memory error!\n",channel);

    /*
     * Clear all interrupt flags
     */
    r4030_write_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5),
		      r4030_read_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5)) |
                      R4030_TC_INTR | R4030_MEM_INTR | R4030_ADDR_INTR);

    /*
     * Enable the desired channel
     */
    r4030_write_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5),
                      r4030_read_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5)) |
                      R4030_CHNL_ENABLE);
}

/*
 * Disable a DMA channel
 */
void vdma_disable(int channel)
{
    if (vdma_debug)
    {
        int status = r4030_read_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5));

        printk("vdma_disable: channel %d\n",channel);
        printk("VDMA: channel %d status: %04x (%s) mode: "
               "%02x addr: %06x count: %06x\n",
               channel,status,((status & 0x600) ? "ERROR" : "OK"),
               (unsigned)r4030_read_reg32(JAZZ_R4030_CHNL_MODE+(channel<<5)),
               (unsigned)r4030_read_reg32(JAZZ_R4030_CHNL_ADDR+(channel<<5)),
               (unsigned)r4030_read_reg32(JAZZ_R4030_CHNL_COUNT+(channel<<5)));
    }
  
    r4030_write_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5),
                      r4030_read_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5)) &
                      ~R4030_CHNL_ENABLE);

    /*
     * After disabling a DMA channel a remote bus register should be
     * read to ensure that the current DMA acknowledge cycle is completed.
     */
    *((volatile unsigned int *)JAZZ_DUMMY_DEVICE);
}

/*
 * Set DMA mode. This function accepts the mode values used
 * to set a PC-style DMA controller. For the SCSI and FDC
 * channels, we also set the default modes each time we're
 * called.
 * NOTE: The FAST and BURST dma modes are supported by the
 * R4030 Rev. 2 and PICA chipsets only. I leave them disabled
 * for now.
 */
void vdma_set_mode(int channel, int mode)
{
    if (vdma_debug)
        printk("vdma_set_mode: channel %d, mode 0x%x\n", channel, mode);

    switch(channel)
    {
    case JAZZ_SCSI_DMA:			/* scsi */
        r4030_write_reg32(JAZZ_R4030_CHNL_MODE+(channel<<5),
/*			  R4030_MODE_FAST | */
/*			  R4030_MODE_BURST | */
                          R4030_MODE_INTR_EN |
                          R4030_MODE_WIDTH_16 |
                          R4030_MODE_ATIME_80);
        break;
      
    case JAZZ_FLOPPY_DMA:	/* floppy */
        r4030_write_reg32(JAZZ_R4030_CHNL_MODE+(channel<<5),
/*			  R4030_MODE_FAST | */
/*			  R4030_MODE_BURST | */
                          R4030_MODE_INTR_EN |
                          R4030_MODE_WIDTH_8 |
                          R4030_MODE_ATIME_120);
        break;

    case JAZZ_AUDIOL_DMA:
    case JAZZ_AUDIOR_DMA:
        printk("VDMA: Audio DMA not supported yet.\n");
        break;
      
    default:
        printk("VDMA: vdma_set_mode() called with unsupported channel %d!\n",
               channel);
    }
  
    switch(mode)
    {
    case DMA_MODE_READ:
        r4030_write_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5),
                          r4030_read_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5)) &
                          ~R4030_CHNL_WRITE);
        break;
      
    case DMA_MODE_WRITE:
        r4030_write_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5),
                          r4030_read_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5)) |
                          R4030_CHNL_WRITE);
      break;
      
    default:
        printk("VDMA: vdma_set_mode() called with unknown dma mode 0x%x\n",mode);
    }
}

/*
 * Set Transfer Address
 */
void vdma_set_addr(int channel, long addr)
{
    if (vdma_debug)
        printk("vdma_set_addr: channel %d, addr %lx\n",channel,addr);

    r4030_write_reg32(JAZZ_R4030_CHNL_ADDR+(channel<<5),addr);
}

/*
 * Set Transfer Count
 */
void vdma_set_count(int channel, int count)
{
    if (vdma_debug)
        printk("vdma_set_count: channel %d, count %08x\n",channel,(unsigned)count);
  
    r4030_write_reg32(JAZZ_R4030_CHNL_COUNT+(channel<<5),count);
}
     
/*
 * Get Residual
 */
int vdma_get_residue(int channel)
{
    int residual;
  
    residual = r4030_read_reg32(JAZZ_R4030_CHNL_COUNT+(channel<<5));

    if (vdma_debug)
        printk("vdma_get_residual: channel %d: residual=%d\n",channel,residual);
  
    return residual;
}

/*
 * Get DMA channel enable register
 */
int vdma_get_enable(int channel)
{
    int enable;
    
    enable = r4030_read_reg32(JAZZ_R4030_CHNL_ENABLE+(channel<<5));
    
    if (vdma_debug)
	printk("vdma_get_enable: channel %d: enable=%d\n",channel,enable);
    
    return enable;
}
