// SPDX-License-Identifier: GPL-2.0-only
/*
 * Sun3 SCSI stuff by Erik Verbruggen (erik@bigmama.xtdnet.nl)
 *
 * Sun3 DMA routines added by Sam Creasey (sammy@sammy.net)
 *
 * VME support added by Sam Creasey
 *
 * TODO: modify this driver to support multiple Sun3 SCSI VME boards
 *
 * 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
 */

#include <linux/types.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/platform_device.h>

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

#include <scsi/scsi_host.h>

/* minimum number of bytes to do dma on */
#define DMA_MIN_SIZE                    129

/* Definitions for the core NCR5380 driver. */

#define NCR5380_implementation_fields   /* none */

#define NCR5380_read(reg)               in_8(hostdata->io + (reg))
#define NCR5380_write(reg, value)       out_8(hostdata->io + (reg), value)

#define NCR5380_queue_command           sun3scsi_queue_command
#define NCR5380_host_reset              sun3scsi_host_reset
#define NCR5380_abort                   sun3scsi_abort
#define NCR5380_info                    sun3scsi_info

#define NCR5380_dma_xfer_len            sun3scsi_dma_xfer_len
#define NCR5380_dma_recv_setup          sun3scsi_dma_count
#define NCR5380_dma_send_setup          sun3scsi_dma_count
#define NCR5380_dma_residual            sun3scsi_dma_residual

#include "NCR5380.h"

/* dma regs start at regbase + 8, directly after the NCR regs */
struct sun3_dma_regs {
        unsigned short dma_addr_hi; /* vme only */
        unsigned short dma_addr_lo; /* vme only */
        unsigned short dma_count_hi; /* vme only */
        unsigned short dma_count_lo; /* vme only */
        unsigned short udc_data; /* udc dma data reg (obio only) */
        unsigned short udc_addr; /* uda dma addr reg (obio only) */
        unsigned short fifo_data; /* fifo data reg,
                                   * holds extra byte on odd dma reads
                                   */
        unsigned short fifo_count;
        unsigned short csr; /* control/status reg */
        unsigned short bpack_hi; /* vme only */
        unsigned short bpack_lo; /* vme only */
        unsigned short ivect; /* vme only */
        unsigned short fifo_count_hi; /* vme only */
};

/* ucd chip specific regs - live in dvma space */
struct sun3_udc_regs {
        unsigned short rsel; /* select regs to load */
        unsigned short addr_hi; /* high word of addr */
        unsigned short addr_lo; /* low word */
        unsigned short count; /* words to be xfer'd */
        unsigned short mode_hi; /* high word of channel mode */
        unsigned short mode_lo; /* low word of channel mode */
};

/* addresses of the udc registers */
#define UDC_MODE 0x38
#define UDC_CSR 0x2e /* command/status */
#define UDC_CHN_HI 0x26 /* chain high word */
#define UDC_CHN_LO 0x22 /* chain lo word */
#define UDC_CURA_HI 0x1a /* cur reg A high */
#define UDC_CURA_LO 0x0a /* cur reg A low */
#define UDC_CURB_HI 0x12 /* cur reg B high */
#define UDC_CURB_LO 0x02 /* cur reg B low */
#define UDC_MODE_HI 0x56 /* mode reg high */
#define UDC_MODE_LO 0x52 /* mode reg low */
#define UDC_COUNT 0x32 /* words to xfer */

/* some udc commands */
#define UDC_RESET 0
#define UDC_CHN_START 0xa0 /* start chain */
#define UDC_INT_ENABLE 0x32 /* channel 1 int on */

/* udc mode words */
#define UDC_MODE_HIWORD 0x40
#define UDC_MODE_LSEND 0xc2
#define UDC_MODE_LRECV 0xd2

/* udc reg selections */
#define UDC_RSEL_SEND 0x282
#define UDC_RSEL_RECV 0x182

/* bits in csr reg */
#define CSR_DMA_ACTIVE 0x8000
#define CSR_DMA_CONFLICT 0x4000
#define CSR_DMA_BUSERR 0x2000

#define CSR_FIFO_EMPTY 0x400 /* fifo flushed? */
#define CSR_SDB_INT 0x200 /* sbc interrupt pending */
#define CSR_DMA_INT 0x100 /* dma interrupt pending */

#define CSR_LEFT 0xc0
#define CSR_LEFT_3 0xc0
#define CSR_LEFT_2 0x80
#define CSR_LEFT_1 0x40
#define CSR_PACK_ENABLE 0x20

#define CSR_DMA_ENABLE 0x10

#define CSR_SEND 0x8 /* 1 = send  0 = recv */
#define CSR_FIFO 0x2 /* reset fifo */
#define CSR_INTR 0x4 /* interrupt enable */
#define CSR_SCSI 0x1

#define VME_DATA24 0x3d00

extern int sun3_map_test(unsigned long, char *);

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);
static int setup_hostid = -1;
module_param(setup_hostid, int, 0);

/* 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

static struct scsi_cmnd *sun3_dma_setup_done;
static volatile struct sun3_dma_regs *dregs;
static struct sun3_udc_regs *udc_regs;
static unsigned char *sun3_dma_orig_addr;
static unsigned long sun3_dma_orig_count;
static int sun3_dma_active;
static unsigned long last_residual;

#ifndef SUN3_SCSI_VME
/* 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);
}
#endif

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

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

#ifdef SUN3_SCSI_VME
        dregs->csr &= ~CSR_DMA_ENABLE;
#endif

        if(csr & ~CSR_GOOD) {
                if (csr & CSR_DMA_BUSERR)
                        shost_printk(KERN_ERR, instance, "bus error in DMA\n");
                if (csr & CSR_DMA_CONFLICT)
                        shost_printk(KERN_ERR, instance, "DMA conflict\n");
                handled = 1;
        }

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

        return IRQ_RETVAL(handled);
}

/* sun3scsi_dma_setup() -- initialize the dma controller for a read/write */
static int sun3scsi_dma_setup(struct NCR5380_hostdata *hostdata,
                              unsigned char *data, int count, int write_flag)
{
        void *addr;

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

#ifdef SUN3_SCSI_VME
        addr = (void *)dvma_map_vme((unsigned long) data, count);
#else
        addr = (void *)dvma_map((unsigned long) data, count);
#endif
                
        sun3_dma_orig_addr = addr;
        sun3_dma_orig_count = count;

#ifndef SUN3_SCSI_VME
        dregs->fifo_count = 0;
        sun3_udc_write(UDC_RESET, UDC_CSR);
        
        /* reset fifo */
        dregs->csr &= ~CSR_FIFO;
        dregs->csr |= CSR_FIFO;
#endif
        
        /* set direction */
        if(write_flag)
                dregs->csr |= CSR_SEND;
        else
                dregs->csr &= ~CSR_SEND;
        
#ifdef SUN3_SCSI_VME
        dregs->csr |= CSR_PACK_ENABLE;

        dregs->dma_addr_hi = ((unsigned long)addr >> 16);
        dregs->dma_addr_lo = ((unsigned long)addr & 0xffff);

        dregs->dma_count_hi = 0;
        dregs->dma_count_lo = 0;
        dregs->fifo_count_hi = 0;
        dregs->fifo_count = 0;
#else
        /* 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) { 
                shost_printk(KERN_ERR, hostdata->host,
                             "FIFO mismatch %04x not %04x\n",
                             dregs->fifo_count, (unsigned int) count);
                NCR5380_dprint(NDEBUG_DMA, hostdata->host);
        }

        /* setup udc */
        udc_regs->addr_hi = (((unsigned long)(addr) & 0xff0000) >> 8);
        udc_regs->addr_lo = ((unsigned long)(addr) & 0xffff);
        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);
#endif
        
        return count;

}

static int sun3scsi_dma_count(struct NCR5380_hostdata *hostdata,
                              unsigned char *data, int count)
{
        return count;
}

static inline int sun3scsi_dma_recv_setup(struct NCR5380_hostdata *hostdata,
                                          unsigned char *data, int count)
{
        return sun3scsi_dma_setup(hostdata, data, count, 0);
}

static inline int sun3scsi_dma_send_setup(struct NCR5380_hostdata *hostdata,
                                          unsigned char *data, int count)
{
        return sun3scsi_dma_setup(hostdata, data, count, 1);
}

static int sun3scsi_dma_residual(struct NCR5380_hostdata *hostdata)
{
        return last_residual;
}

static int sun3scsi_dma_xfer_len(struct NCR5380_hostdata *hostdata,
                                 struct scsi_cmnd *cmd)
{
        int wanted_len = NCR5380_to_ncmd(cmd)->this_residual;

        if (wanted_len < DMA_MIN_SIZE || blk_rq_is_passthrough(scsi_cmd_to_rq(cmd)))
                return 0;

        return wanted_len;
}

static inline int sun3scsi_dma_start(unsigned long count, unsigned char *data)
{
#ifdef SUN3_SCSI_VME
        unsigned short csr;

        csr = dregs->csr;

        dregs->dma_count_hi = (sun3_dma_orig_count >> 16);
        dregs->dma_count_lo = (sun3_dma_orig_count & 0xffff);

        dregs->fifo_count_hi = (sun3_dma_orig_count >> 16);
        dregs->fifo_count = (sun3_dma_orig_count & 0xffff);

/*      if(!(csr & CSR_DMA_ENABLE))
 *              dregs->csr |= CSR_DMA_ENABLE;
 */
#else
    sun3_udc_write(UDC_CHN_START, UDC_CSR);
#endif
    
    return 0;
}

/* clean up after our dma is done */
static int sun3scsi_dma_finish(enum dma_data_direction data_dir)
{
        const bool write_flag = data_dir == DMA_TO_DEVICE;
        unsigned short __maybe_unused count;
        unsigned short fifo;
        int ret = 0;
        
        sun3_dma_active = 0;

#ifdef SUN3_SCSI_VME
        dregs->csr &= ~CSR_DMA_ENABLE;

        fifo = dregs->fifo_count;
        if (write_flag) {
                if ((fifo > 0) && (fifo < sun3_dma_orig_count))
                        fifo++;
        }

        last_residual = fifo;
        /* empty bytes from the fifo which didn't make it */
        if ((!write_flag) && (dregs->csr & CSR_LEFT)) {
                unsigned char *vaddr;

                vaddr = (unsigned char *)dvma_vmetov(sun3_dma_orig_addr);

                vaddr += (sun3_dma_orig_count - fifo);
                vaddr--;

                switch (dregs->csr & CSR_LEFT) {
                case CSR_LEFT_3:
                        *vaddr = (dregs->bpack_lo & 0xff00) >> 8;
                        vaddr--;
                        fallthrough;

                case CSR_LEFT_2:
                        *vaddr = (dregs->bpack_hi & 0x00ff);
                        vaddr--;
                        fallthrough;

                case CSR_LEFT_1:
                        *vaddr = (dregs->bpack_hi & 0xff00) >> 8;
                        break;
                }
        }
#else
        // 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);
                }
        }

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

        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);
        }
#endif

        dvma_unmap(sun3_dma_orig_addr);
        sun3_dma_orig_addr = NULL;

#ifdef SUN3_SCSI_VME
        dregs->dma_addr_hi = 0;
        dregs->dma_addr_lo = 0;
        dregs->dma_count_hi = 0;
        dregs->dma_count_lo = 0;

        dregs->fifo_count = 0;
        dregs->fifo_count_hi = 0;

        dregs->csr &= ~CSR_SEND;
/*      dregs->csr |= CSR_DMA_ENABLE; */
#else
        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;
#endif
        
        sun3_dma_setup_done = NULL;

        return ret;

}
        
#include "NCR5380.c"

#ifdef SUN3_SCSI_VME
#define SUN3_SCSI_NAME          "Sun3 NCR5380 VME SCSI"
#define DRV_MODULE_NAME         "sun3_scsi_vme"
#else
#define SUN3_SCSI_NAME          "Sun3 NCR5380 SCSI"
#define DRV_MODULE_NAME         "sun3_scsi"
#endif

#define PFX                     DRV_MODULE_NAME ": "

static struct scsi_host_template sun3_scsi_template = {
        .module                 = THIS_MODULE,
        .proc_name              = DRV_MODULE_NAME,
        .name                   = SUN3_SCSI_NAME,
        .info                   = sun3scsi_info,
        .queuecommand           = sun3scsi_queue_command,
        .eh_abort_handler       = sun3scsi_abort,
        .eh_host_reset_handler  = sun3scsi_host_reset,
        .can_queue              = 16,
        .this_id                = 7,
        .sg_tablesize           = 1,
        .cmd_per_lun            = 2,
        .dma_boundary           = PAGE_SIZE - 1,
        .cmd_size               = sizeof(struct NCR5380_cmd),
};

static int __init sun3_scsi_probe(struct platform_device *pdev)
{
        struct Scsi_Host *instance;
        struct NCR5380_hostdata *hostdata;
        int error;
        struct resource *irq, *mem;
        void __iomem *ioaddr;
        int host_flags = 0;
#ifdef SUN3_SCSI_VME
        int i;
#endif

        if (setup_can_queue > 0)
                sun3_scsi_template.can_queue = setup_can_queue;
        if (setup_cmd_per_lun > 0)
                sun3_scsi_template.cmd_per_lun = setup_cmd_per_lun;
        if (setup_sg_tablesize > 0)
                sun3_scsi_template.sg_tablesize = setup_sg_tablesize;
        if (setup_hostid >= 0)
                sun3_scsi_template.this_id = setup_hostid & 7;

#ifdef SUN3_SCSI_VME
        ioaddr = NULL;
        for (i = 0; i < 2; i++) {
                unsigned char x;

                irq = platform_get_resource(pdev, IORESOURCE_IRQ, i);
                mem = platform_get_resource(pdev, IORESOURCE_MEM, i);
                if (!irq || !mem)
                        break;

                ioaddr = sun3_ioremap(mem->start, resource_size(mem),
                                      SUN3_PAGE_TYPE_VME16);
                dregs = (struct sun3_dma_regs *)(ioaddr + 8);

                if (sun3_map_test((unsigned long)dregs, &x)) {
                        unsigned short oldcsr;

                        oldcsr = dregs->csr;
                        dregs->csr = 0;
                        udelay(SUN3_DMA_DELAY);
                        if (dregs->csr == 0x1400)
                                break;

                        dregs->csr = oldcsr;
                }

                iounmap(ioaddr);
                ioaddr = NULL;
        }
        if (!ioaddr)
                return -ENODEV;
#else
        irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!irq || !mem)
                return -ENODEV;

        ioaddr = ioremap(mem->start, resource_size(mem));
        dregs = (struct sun3_dma_regs *)(ioaddr + 8);

        udc_regs = dvma_malloc(sizeof(struct sun3_udc_regs));
        if (!udc_regs) {
                pr_err(PFX "couldn't allocate DVMA memory!\n");
                iounmap(ioaddr);
                return -ENOMEM;
        }
#endif

        instance = scsi_host_alloc(&sun3_scsi_template,
                                   sizeof(struct NCR5380_hostdata));
        if (!instance) {
                error = -ENOMEM;
                goto fail_alloc;
        }

        instance->irq = irq->start;

        hostdata = shost_priv(instance);
        hostdata->base = mem->start;
        hostdata->io = ioaddr;

        error = NCR5380_init(instance, host_flags);
        if (error)
                goto fail_init;

        error = request_irq(instance->irq, scsi_sun3_intr, 0,
                            "NCR5380", instance);
        if (error) {
                pr_err(PFX "scsi%d: IRQ %d not free, bailing out\n",
                       instance->host_no, instance->irq);
                goto fail_irq;
        }

        dregs->csr = 0;
        udelay(SUN3_DMA_DELAY);
        dregs->csr = CSR_SCSI | CSR_FIFO | CSR_INTR;
        udelay(SUN3_DMA_DELAY);
        dregs->fifo_count = 0;
#ifdef SUN3_SCSI_VME
        dregs->fifo_count_hi = 0;
        dregs->dma_addr_hi = 0;
        dregs->dma_addr_lo = 0;
        dregs->dma_count_hi = 0;
        dregs->dma_count_lo = 0;

        dregs->ivect = VME_DATA24 | (instance->irq & 0xff);
#endif

        NCR5380_maybe_reset_bus(instance);

        error = scsi_add_host(instance, NULL);
        if (error)
                goto fail_host;

        platform_set_drvdata(pdev, instance);

        scsi_scan_host(instance);
        return 0;

fail_host:
        free_irq(instance->irq, instance);
fail_irq:
        NCR5380_exit(instance);
fail_init:
        scsi_host_put(instance);
fail_alloc:
        if (udc_regs)
                dvma_free(udc_regs);
        iounmap(ioaddr);
        return error;
}

static void __exit sun3_scsi_remove(struct platform_device *pdev)
{
        struct Scsi_Host *instance = platform_get_drvdata(pdev);
        struct NCR5380_hostdata *hostdata = shost_priv(instance);
        void __iomem *ioaddr = hostdata->io;

        scsi_remove_host(instance);
        free_irq(instance->irq, instance);
        NCR5380_exit(instance);
        scsi_host_put(instance);
        if (udc_regs)
                dvma_free(udc_regs);
        iounmap(ioaddr);
}

/*
 * sun3_scsi_remove() lives in .exit.text. For drivers registered via
 * module_platform_driver_probe() this is ok because they cannot get unbound at
 * runtime. So mark the driver struct with __refdata to prevent modpost
 * triggering a section mismatch warning.
 */
static struct platform_driver sun3_scsi_driver __refdata = {
        .remove = __exit_p(sun3_scsi_remove),
        .driver = {
                .name   = DRV_MODULE_NAME,
        },
};

module_platform_driver_probe(sun3_scsi_driver, sun3_scsi_probe);

MODULE_ALIAS("platform:" DRV_MODULE_NAME);
MODULE_DESCRIPTION("Sun3 NCR5380 SCSI controller driver");
MODULE_LICENSE("GPL");