/*
 * 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/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/spinlock.h>
#include <linux/gfp.h>
#include <asm/mipsregs.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 VDMA_PGTBL_ENTRY *pgtbl;

static DEFINE_SPINLOCK(vdma_lock);

/*
 * 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)
{
        unsigned long paddr = 0;
        int i;

        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
 */
static int __init vdma_init(void)
{
        /*
         * 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.
         */
        pgtbl = (VDMA_PGTBL_ENTRY *)__get_free_pages(GFP_KERNEL | GFP_DMA,
                                                    get_order(VDMA_PGTBL_SIZE));
        BUG_ON(!pgtbl);
        dma_cache_wback_inv((unsigned long)pgtbl, VDMA_PGTBL_SIZE);
        pgtbl = (VDMA_PGTBL_ENTRY *)KSEG1ADDR(pgtbl);

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

        r4030_write_reg32(JAZZ_R4030_TRSTBL_BASE, CPHYSADDR(pgtbl));
        r4030_write_reg32(JAZZ_R4030_TRSTBL_LIM, VDMA_PGTBL_SIZE);
        r4030_write_reg32(JAZZ_R4030_TRSTBL_INV, 0);

        printk(KERN_INFO "VDMA: R4030 DMA pagetables initialized.\n");
        return 0;
}

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

        /* 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 */
        }

        spin_lock_irqsave(&vdma_lock, flags);
        /*
         * Find free chunk
         */
        pages = VDMA_PAGE(paddr + size) - VDMA_PAGE(paddr) + 1;
        first = 0;
        while (1) {
                while (pgtbl[first].owner != VDMA_PAGE_EMPTY &&
                       first < VDMA_PGTBL_ENTRIES) first++;
                if (first + pages > VDMA_PGTBL_ENTRIES) {       /* nothing free */
                        spin_unlock_irqrestore(&vdma_lock, flags);
                        return VDMA_ERROR;
                }

                last = first + 1;
                while (pgtbl[last].owner == VDMA_PAGE_EMPTY
                       && last - first < pages)
                        last++;

                if (last - first == pages)
                        break;  /* found */
                first = last + 1;
        }

        /*
         * Mark pages as allocated
         */
        laddr = (first << 12) + (paddr & (VDMA_PAGESIZE - 1));
        frame = paddr & ~(VDMA_PAGESIZE - 1);

        for (i = first; i < last; i++) {
                pgtbl[i].frame = frame;
                pgtbl[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 ", pgtbl[i].frame);
                printk("\nOWNER: ");
                for (i = first; i < last; i++)
                        printk("%08x ", pgtbl[i].owner);
                printk("\n");
        }

        spin_unlock_irqrestore(&vdma_lock, flags);

        return laddr;
}

EXPORT_SYMBOL(vdma_alloc);

/*
 * 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)
{
        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 (i < VDMA_PGTBL_ENTRIES && pgtbl[i].owner == laddr) {
                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;
}

EXPORT_SYMBOL(vdma_free);

/*
 * 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)
{
        int first, pages;

        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 */
        }

        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;

        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));
}

EXPORT_SYMBOL(vdma_phys2log);

/*
 * Translate a logical DMA address to a physical address
 */
unsigned long vdma_log2phys(unsigned long laddr)
{
        return pgtbl[laddr >> 12].frame + (laddr & (VDMA_PAGESIZE - 1));
}

EXPORT_SYMBOL(vdma_log2phys);

/*
 * 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);
}

EXPORT_SYMBOL(vdma_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);
}

EXPORT_SYMBOL(vdma_disable);

/*
 * 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);
        }
}

EXPORT_SYMBOL(vdma_set_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);
}

EXPORT_SYMBOL(vdma_set_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);
}

EXPORT_SYMBOL(vdma_set_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;
}

arch_initcall(vdma_init);