/*
 * Sun3 SCSI stuff by Erik Verbruggen (erik@bigmama.xtdnet.nl)
 *
 * Sun3 DMA routines added by Sam Creasey (sammy@sammy.net)
 *
 * Adapted from mac_scsinew.c:
 */
/*
 * Generic Macintosh NCR5380 driver
 *
 * Copyright 1998, Michael Schmitz <mschmitz@lbl.gov>
 *
 * derived in part from:
 */
/*
 * Generic Generic NCR5380 driver
 *
 * Copyright 1995, Russell King
 *
 * ALPHA RELEASE 1.
 *
 * For more information, please consult
 *
 * NCR 5380 Family
 * SCSI Protocol Controller
 * Databook
 *
 * NCR Microelectronics
 * 1635 Aeroplaza Drive
 * Colorado Springs, CO 80916
 * 1+ (719) 578-3400
 * 1+ (800) 334-5454
 */


/*
 * This is from mac_scsi.h, but hey, maybe this is useful for Sun3 too! :)
 *
 * Options :
 *
 * PARITY - enable parity checking.  Not supported.
 *
 * SCSI2 - enable support for SCSI-II tagged queueing.  Untested.
 *
 * USLEEP - enable support for devices that don't disconnect.  Untested.
 */

/*
 * $Log: sun3_NCR5380.c,v $
 */

#define AUTOSENSE

#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/ctype.h>
#include <linux/delay.h>

#include <linux/module.h>
#include <linux/signal.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/blkdev.h>

#include <asm/io.h>
#include <asm/system.h>

#include <asm/sun3ints.h>
#include <asm/dvma.h>
#include <asm/idprom.h>
#include <asm/machines.h>

/* dma on! */
#define REAL_DMA

#include "scsi.h"
#include "initio.h"
#include <scsi/scsi_host.h>
#include "sun3_scsi.h"

static void NCR5380_print(struct Scsi_Host *instance);

/* #define OLDDMA */

#define USE_WRAPPER
/*#define RESET_BOOT */
#define DRIVER_SETUP

#define NDEBUG 0

/*
 * BUG can be used to trigger a strange code-size related hang on 2.1 kernels
 */
#ifdef BUG
#undef RESET_BOOT
#undef DRIVER_SETUP
#endif

/* #define SUPPORT_TAGS */

#define ENABLE_IRQ()    enable_irq( IRQ_SUN3_SCSI ); 


static irqreturn_t scsi_sun3_intr(int irq, void *dummy);
static inline unsigned char sun3scsi_read(int reg);
static inline void sun3scsi_write(int reg, int value);

static int setup_can_queue = -1;
module_param(setup_can_queue, int, 0);
static int setup_cmd_per_lun = -1;
module_param(setup_cmd_per_lun, int, 0);
static int setup_sg_tablesize = -1;
module_param(setup_sg_tablesize, int, 0);
#ifdef SUPPORT_TAGS
static int setup_use_tagged_queuing = -1;
module_param(setup_use_tagged_queuing, int, 0);
#endif
static int setup_hostid = -1;
module_param(setup_hostid, int, 0);

static struct scsi_cmnd *sun3_dma_setup_done = NULL;

#define AFTER_RESET_DELAY       (HZ/2)

/* ms to wait after hitting dma regs */
#define SUN3_DMA_DELAY 10

/* dvma buffer to allocate -- 32k should hopefully be more than sufficient */
#define SUN3_DVMA_BUFSIZE 0xe000

/* minimum number of bytes to do dma on */
#define SUN3_DMA_MINSIZE 128

static volatile unsigned char *sun3_scsi_regp;
static volatile struct sun3_dma_regs *dregs;
#ifdef OLDDMA
static unsigned char *dmabuf = NULL; /* dma memory buffer */
#endif
static struct sun3_udc_regs *udc_regs = NULL;
static unsigned char *sun3_dma_orig_addr = NULL;
static unsigned long sun3_dma_orig_count = 0;
static int sun3_dma_active = 0;
static unsigned long last_residual = 0;

/*
 * NCR 5380 register access functions
 */

static inline unsigned char sun3scsi_read(int reg)
{
        return( sun3_scsi_regp[reg] );
}

static inline void sun3scsi_write(int reg, int value)
{
        sun3_scsi_regp[reg] = value;
}

/* dma controller register access functions */

static inline unsigned short sun3_udc_read(unsigned char reg)
{
        unsigned short ret;

        dregs->udc_addr = UDC_CSR;
        udelay(SUN3_DMA_DELAY);
        ret = dregs->udc_data;
        udelay(SUN3_DMA_DELAY);
        
        return ret;
}

static inline void sun3_udc_write(unsigned short val, unsigned char reg)
{
        dregs->udc_addr = reg;
        udelay(SUN3_DMA_DELAY);
        dregs->udc_data = val;
        udelay(SUN3_DMA_DELAY);
}

/*
 * XXX: status debug
 */
static struct Scsi_Host *default_instance;

/*
 * Function : int sun3scsi_detect(struct scsi_host_template * tpnt)
 *
 * Purpose : initializes mac NCR5380 driver based on the
 *      command line / compile time port and irq definitions.
 *
 * Inputs : tpnt - template for this SCSI adapter.
 *
 * Returns : 1 if a host adapter was found, 0 if not.
 *
 */
 
int sun3scsi_detect(struct scsi_host_template * tpnt)
{
        unsigned long ioaddr;
        static int called = 0;
        struct Scsi_Host *instance;

        /* check that this machine has an onboard 5380 */
        switch(idprom->id_machtype) {
        case SM_SUN3|SM_3_50:
        case SM_SUN3|SM_3_60:
                break;

        default:
                return 0;
        }

        if(called)
                return 0;

        tpnt->proc_name = "Sun3 5380 SCSI";

        /* setup variables */
        tpnt->can_queue =
                (setup_can_queue > 0) ? setup_can_queue : CAN_QUEUE;
        tpnt->cmd_per_lun =
                (setup_cmd_per_lun > 0) ? setup_cmd_per_lun : CMD_PER_LUN;
        tpnt->sg_tablesize = 
                (setup_sg_tablesize >= 0) ? setup_sg_tablesize : SG_TABLESIZE;

        if (setup_hostid >= 0)
                tpnt->this_id = setup_hostid;
        else {
                /* use 7 as default */
                tpnt->this_id = 7;
        }

        ioaddr = (unsigned long)ioremap(IOBASE_SUN3_SCSI, PAGE_SIZE);
        sun3_scsi_regp = (unsigned char *)ioaddr;

        dregs = (struct sun3_dma_regs *)(((unsigned char *)ioaddr) + 8);

        if((udc_regs = dvma_malloc(sizeof(struct sun3_udc_regs)))
           == NULL) {
             printk("SUN3 Scsi couldn't allocate DVMA memory!\n");
             return 0;
        }
#ifdef OLDDMA
        if((dmabuf = dvma_malloc_align(SUN3_DVMA_BUFSIZE, 0x10000)) == NULL) {
             printk("SUN3 Scsi couldn't allocate DVMA memory!\n");
             return 0;
        }
#endif
#ifdef SUPPORT_TAGS
        if (setup_use_tagged_queuing < 0)
                setup_use_tagged_queuing = USE_TAGGED_QUEUING;
#endif

        instance = scsi_register (tpnt, sizeof(struct NCR5380_hostdata));
        if(instance == NULL)
                return 0;
                
        default_instance = instance;

        instance->io_port = (unsigned long) ioaddr;
        instance->irq = IRQ_SUN3_SCSI;

        NCR5380_init(instance, 0);

        instance->n_io_port = 32;

        ((struct NCR5380_hostdata *)instance->hostdata)->ctrl = 0;

        if (request_irq(instance->irq, scsi_sun3_intr,
                             0, "Sun3SCSI-5380", instance)) {
#ifndef REAL_DMA
                printk("scsi%d: IRQ%d not free, interrupts disabled\n",
                       instance->host_no, instance->irq);
                instance->irq = SCSI_IRQ_NONE;
#else
                printk("scsi%d: IRQ%d not free, bailing out\n",
                       instance->host_no, instance->irq);
                return 0;
#endif
        }
        
        printk("scsi%d: Sun3 5380 at port %lX irq", instance->host_no, instance->io_port);
        if (instance->irq == SCSI_IRQ_NONE)
                printk ("s disabled");
        else
                printk (" %d", instance->irq);
        printk(" options CAN_QUEUE=%d CMD_PER_LUN=%d release=%d",
               instance->can_queue, instance->cmd_per_lun,
               SUN3SCSI_PUBLIC_RELEASE);
        printk("\nscsi%d:", instance->host_no);
        NCR5380_print_options(instance);
        printk("\n");

        dregs->csr = 0;
        udelay(SUN3_DMA_DELAY);
        dregs->csr = CSR_SCSI | CSR_FIFO | CSR_INTR;
        udelay(SUN3_DMA_DELAY);
        dregs->fifo_count = 0;

        called = 1;

#ifdef RESET_BOOT
        sun3_scsi_reset_boot(instance);
#endif

        return 1;
}

int sun3scsi_release (struct Scsi_Host *shpnt)
{
        if (shpnt->irq != SCSI_IRQ_NONE)
                free_irq(shpnt->irq, shpnt);

        iounmap((void *)sun3_scsi_regp);

        return 0;
}

#ifdef RESET_BOOT
/*
 * Our 'bus reset on boot' function
 */

static void sun3_scsi_reset_boot(struct Scsi_Host *instance)
{
        unsigned long end;

        NCR5380_local_declare();
        NCR5380_setup(instance);
        
        /*
         * Do a SCSI reset to clean up the bus during initialization. No
         * messing with the queues, interrupts, or locks necessary here.
         */

        printk( "Sun3 SCSI: resetting the SCSI bus..." );

        /* switch off SCSI IRQ - catch an interrupt without IRQ bit set else */
//              sun3_disable_irq( IRQ_SUN3_SCSI );

        /* get in phase */
        NCR5380_write( TARGET_COMMAND_REG,
                      PHASE_SR_TO_TCR( NCR5380_read(STATUS_REG) ));

        /* assert RST */
        NCR5380_write( INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST );

        /* The min. reset hold time is 25us, so 40us should be enough */
        udelay( 50 );

        /* reset RST and interrupt */
        NCR5380_write( INITIATOR_COMMAND_REG, ICR_BASE );
        NCR5380_read( RESET_PARITY_INTERRUPT_REG );

        for( end = jiffies + AFTER_RESET_DELAY; time_before(jiffies, end); )
                barrier();

        /* switch on SCSI IRQ again */
//              sun3_enable_irq( IRQ_SUN3_SCSI );

        printk( " done\n" );
}
#endif

const char * sun3scsi_info (struct Scsi_Host *spnt) {
    return "";
}

// safe bits for the CSR
#define CSR_GOOD 0x060f

static irqreturn_t scsi_sun3_intr(int irq, void *dummy)
{
        unsigned short csr = dregs->csr;
        int handled = 0;

        if(csr & ~CSR_GOOD) {
                if(csr & CSR_DMA_BUSERR) {
                        printk("scsi%d: bus error in dma\n", default_instance->host_no);
                }

                if(csr & CSR_DMA_CONFLICT) {
                        printk("scsi%d: dma conflict\n", default_instance->host_no);
                }
                handled = 1;
        }

        if(csr & (CSR_SDB_INT | CSR_DMA_INT)) {
                NCR5380_intr(irq, dummy);
                handled = 1;
        }

        return IRQ_RETVAL(handled);
}

/*
 * Debug stuff - to be called on NMI, or sysrq key. Use at your own risk; 
 * reentering NCR5380_print_status seems to have ugly side effects
 */

/* this doesn't seem to get used at all -- sam */
#if 0
void sun3_sun3_debug (void)
{
        unsigned long flags;
        NCR5380_local_declare();

        if (default_instance) {
                        local_irq_save(flags);
                        NCR5380_print_status(default_instance);
                        local_irq_restore(flags);
        }
}
#endif


/* sun3scsi_dma_setup() -- initialize the dma controller for a read/write */
static unsigned long sun3scsi_dma_setup(void *data, unsigned long count, int write_flag)
{
#ifdef OLDDMA
        if(write_flag) 
                memcpy(dmabuf, data, count);
        else {
                sun3_dma_orig_addr = data;
                sun3_dma_orig_count = count;
        }
#else
        void *addr;

        if(sun3_dma_orig_addr != NULL)
                dvma_unmap(sun3_dma_orig_addr);

//      addr = sun3_dvma_page((unsigned long)data, (unsigned long)dmabuf);
        addr = (void *)dvma_map((unsigned long) data, count);
                
        sun3_dma_orig_addr = addr;
        sun3_dma_orig_count = count;
#endif
        dregs->fifo_count = 0;
        sun3_udc_write(UDC_RESET, UDC_CSR);
        
        /* reset fifo */
        dregs->csr &= ~CSR_FIFO;
        dregs->csr |= CSR_FIFO;
        
        /* set direction */
        if(write_flag)
                dregs->csr |= CSR_SEND;
        else
                dregs->csr &= ~CSR_SEND;
        
        /* byte count for fifo */
        dregs->fifo_count = count;

        sun3_udc_write(UDC_RESET, UDC_CSR);
        
        /* reset fifo */
        dregs->csr &= ~CSR_FIFO;
        dregs->csr |= CSR_FIFO;
        
        if(dregs->fifo_count != count) { 
                printk("scsi%d: fifo_mismatch %04x not %04x\n",
                       default_instance->host_no, dregs->fifo_count,
                       (unsigned int) count);
                NCR5380_print(default_instance);
        }

        /* setup udc */
#ifdef OLDDMA
        udc_regs->addr_hi = ((dvma_vtob(dmabuf) & 0xff0000) >> 8);
        udc_regs->addr_lo = (dvma_vtob(dmabuf) & 0xffff);
#else
        udc_regs->addr_hi = (((unsigned long)(addr) & 0xff0000) >> 8);
        udc_regs->addr_lo = ((unsigned long)(addr) & 0xffff);
#endif
        udc_regs->count = count/2; /* count in words */
        udc_regs->mode_hi = UDC_MODE_HIWORD;
        if(write_flag) {
                if(count & 1)
                        udc_regs->count++;
                udc_regs->mode_lo = UDC_MODE_LSEND;
                udc_regs->rsel = UDC_RSEL_SEND;
        } else {
                udc_regs->mode_lo = UDC_MODE_LRECV;
                udc_regs->rsel = UDC_RSEL_RECV;
        }
        
        /* announce location of regs block */
        sun3_udc_write(((dvma_vtob(udc_regs) & 0xff0000) >> 8),
                       UDC_CHN_HI); 

        sun3_udc_write((dvma_vtob(udc_regs) & 0xffff), UDC_CHN_LO);

        /* set dma master on */
        sun3_udc_write(0xd, UDC_MODE);

        /* interrupt enable */
        sun3_udc_write(UDC_INT_ENABLE, UDC_CSR);
        
        return count;

}

static inline unsigned long sun3scsi_dma_count(struct Scsi_Host *instance)
{
        unsigned short resid;

        dregs->udc_addr = 0x32; 
        udelay(SUN3_DMA_DELAY);
        resid = dregs->udc_data;
        udelay(SUN3_DMA_DELAY);
        resid *= 2;

        return (unsigned long) resid;
}

static inline unsigned long sun3scsi_dma_residual(struct Scsi_Host *instance)
{
        return last_residual;
}

static inline unsigned long sun3scsi_dma_xfer_len(unsigned long wanted,
                                                  struct scsi_cmnd *cmd,
                                                  int write_flag)
{
        if(blk_fs_request(cmd->request))
                return wanted;
        else
                return 0;
}

static inline int sun3scsi_dma_start(unsigned long count, unsigned char *data)
{

    sun3_udc_write(UDC_CHN_START, UDC_CSR);
    
    return 0;
}

/* clean up after our dma is done */
static int sun3scsi_dma_finish(int write_flag)
{
        unsigned short count;
        unsigned short fifo;
        int ret = 0;
        
        sun3_dma_active = 0;
#if 1
        // check to empty the fifo on a read
        if(!write_flag) {
                int tmo = 20000; /* .2 sec */
                
                while(1) {
                        if(dregs->csr & CSR_FIFO_EMPTY)
                                break;

                        if(--tmo <= 0) {
                                printk("sun3scsi: fifo failed to empty!\n");
                                return 1;
                        }
                        udelay(10);
                }
        }
                
#endif

        count = sun3scsi_dma_count(default_instance);
#ifdef OLDDMA

        /* if we've finished a read, copy out the data we read */
        if(sun3_dma_orig_addr) {
                /* check for residual bytes after dma end */
                if(count && (NCR5380_read(BUS_AND_STATUS_REG) &
                             (BASR_PHASE_MATCH | BASR_ACK))) {
                        printk("scsi%d: sun3_scsi_finish: read overrun baby... ", default_instance->host_no);
                        printk("basr now %02x\n", NCR5380_read(BUS_AND_STATUS_REG));
                        ret = count;
                }
                
                /* copy in what we dma'd no matter what */
                memcpy(sun3_dma_orig_addr, dmabuf, sun3_dma_orig_count);
                sun3_dma_orig_addr = NULL;

        }
#else

        fifo = dregs->fifo_count;
        last_residual = fifo;

        /* empty bytes from the fifo which didn't make it */
        if((!write_flag) && (count - fifo) == 2) {
                unsigned short data;
                unsigned char *vaddr;

                data = dregs->fifo_data;
                vaddr = (unsigned char *)dvma_btov(sun3_dma_orig_addr);
                
                vaddr += (sun3_dma_orig_count - fifo);

                vaddr[-2] = (data & 0xff00) >> 8;
                vaddr[-1] = (data & 0xff);
        }

        dvma_unmap(sun3_dma_orig_addr);
        sun3_dma_orig_addr = NULL;
#endif
        sun3_udc_write(UDC_RESET, UDC_CSR);
        dregs->fifo_count = 0;
        dregs->csr &= ~CSR_SEND;

        /* reset fifo */
        dregs->csr &= ~CSR_FIFO;
        dregs->csr |= CSR_FIFO;
        
        sun3_dma_setup_done = NULL;

        return ret;

}
        
#include "sun3_NCR5380.c"

static struct scsi_host_template driver_template = {
        .name                   = SUN3_SCSI_NAME,
        .detect                 = sun3scsi_detect,
        .release                = sun3scsi_release,
        .info                   = sun3scsi_info,
        .queuecommand           = sun3scsi_queue_command,
        .eh_abort_handler       = sun3scsi_abort,
        .eh_bus_reset_handler   = sun3scsi_bus_reset,
        .can_queue              = CAN_QUEUE,
        .this_id                = 7,
        .sg_tablesize           = SG_TABLESIZE,
        .cmd_per_lun            = CMD_PER_LUN,
        .use_clustering         = DISABLE_CLUSTERING
};


#include "scsi_module.c"

MODULE_LICENSE("GPL");