// SPDX-License-Identifier: GPL-2.0-only
#include <linux/types.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/zorro.h>
#include <linux/module.h>

#include <asm/page.h>
#include <asm/amigaints.h>
#include <asm/amigahw.h>

#include "scsi.h"
#include "wd33c93.h"
#include "gvp11.h"


#define CHECK_WD33C93

struct gvp11_hostdata {
        struct WD33C93_hostdata wh;
        struct gvp11_scsiregs *regs;
};

static irqreturn_t gvp11_intr(int irq, void *data)
{
        struct Scsi_Host *instance = data;
        struct gvp11_hostdata *hdata = shost_priv(instance);
        unsigned int status = hdata->regs->CNTR;
        unsigned long flags;

        if (!(status & GVP11_DMAC_INT_PENDING))
                return IRQ_NONE;

        spin_lock_irqsave(instance->host_lock, flags);
        wd33c93_intr(instance);
        spin_unlock_irqrestore(instance->host_lock, flags);
        return IRQ_HANDLED;
}

static int gvp11_xfer_mask = 0;

void gvp11_setup(char *str, int *ints)
{
        gvp11_xfer_mask = ints[1];
}

static int dma_setup(struct scsi_cmnd *cmd, int dir_in)
{
        struct Scsi_Host *instance = cmd->device->host;
        struct gvp11_hostdata *hdata = shost_priv(instance);
        struct WD33C93_hostdata *wh = &hdata->wh;
        struct gvp11_scsiregs *regs = hdata->regs;
        unsigned short cntr = GVP11_DMAC_INT_ENABLE;
        unsigned long addr = virt_to_bus(cmd->SCp.ptr);
        int bank_mask;
        static int scsi_alloc_out_of_range = 0;

        /* use bounce buffer if the physical address is bad */
        if (addr & wh->dma_xfer_mask) {
                wh->dma_bounce_len = (cmd->SCp.this_residual + 511) & ~0x1ff;

                if (!scsi_alloc_out_of_range) {
                        wh->dma_bounce_buffer =
                                kmalloc(wh->dma_bounce_len, GFP_KERNEL);
                        wh->dma_buffer_pool = BUF_SCSI_ALLOCED;
                }

                if (scsi_alloc_out_of_range ||
                    !wh->dma_bounce_buffer) {
                        wh->dma_bounce_buffer =
                                amiga_chip_alloc(wh->dma_bounce_len,
                                                 "GVP II SCSI Bounce Buffer");

                        if (!wh->dma_bounce_buffer) {
                                wh->dma_bounce_len = 0;
                                return 1;
                        }

                        wh->dma_buffer_pool = BUF_CHIP_ALLOCED;
                }

                /* check if the address of the bounce buffer is OK */
                addr = virt_to_bus(wh->dma_bounce_buffer);

                if (addr & wh->dma_xfer_mask) {
                        /* fall back to Chip RAM if address out of range */
                        if (wh->dma_buffer_pool == BUF_SCSI_ALLOCED) {
                                kfree(wh->dma_bounce_buffer);
                                scsi_alloc_out_of_range = 1;
                        } else {
                                amiga_chip_free(wh->dma_bounce_buffer);
                        }

                        wh->dma_bounce_buffer =
                                amiga_chip_alloc(wh->dma_bounce_len,
                                                 "GVP II SCSI Bounce Buffer");

                        if (!wh->dma_bounce_buffer) {
                                wh->dma_bounce_len = 0;
                                return 1;
                        }

                        addr = virt_to_bus(wh->dma_bounce_buffer);
                        wh->dma_buffer_pool = BUF_CHIP_ALLOCED;
                }

                if (!dir_in) {
                        /* copy to bounce buffer for a write */
                        memcpy(wh->dma_bounce_buffer, cmd->SCp.ptr,
                               cmd->SCp.this_residual);
                }
        }

        /* setup dma direction */
        if (!dir_in)
                cntr |= GVP11_DMAC_DIR_WRITE;

        wh->dma_dir = dir_in;
        regs->CNTR = cntr;

        /* setup DMA *physical* address */
        regs->ACR = addr;

        if (dir_in) {
                /* invalidate any cache */
                cache_clear(addr, cmd->SCp.this_residual);
        } else {
                /* push any dirty cache */
                cache_push(addr, cmd->SCp.this_residual);
        }

        bank_mask = (~wh->dma_xfer_mask >> 18) & 0x01c0;
        if (bank_mask)
                regs->BANK = bank_mask & (addr >> 18);

        /* start DMA */
        regs->ST_DMA = 1;

        /* return success */
        return 0;
}

static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt,
                     int status)
{
        struct gvp11_hostdata *hdata = shost_priv(instance);
        struct WD33C93_hostdata *wh = &hdata->wh;
        struct gvp11_scsiregs *regs = hdata->regs;

        /* stop DMA */
        regs->SP_DMA = 1;
        /* remove write bit from CONTROL bits */
        regs->CNTR = GVP11_DMAC_INT_ENABLE;

        /* copy from a bounce buffer, if necessary */
        if (status && wh->dma_bounce_buffer) {
                if (wh->dma_dir && SCpnt)
                        memcpy(SCpnt->SCp.ptr, wh->dma_bounce_buffer,
                               SCpnt->SCp.this_residual);

                if (wh->dma_buffer_pool == BUF_SCSI_ALLOCED)
                        kfree(wh->dma_bounce_buffer);
                else
                        amiga_chip_free(wh->dma_bounce_buffer);

                wh->dma_bounce_buffer = NULL;
                wh->dma_bounce_len = 0;
        }
}

static struct scsi_host_template gvp11_scsi_template = {
        .module                 = THIS_MODULE,
        .name                   = "GVP Series II SCSI",
        .show_info              = wd33c93_show_info,
        .write_info             = wd33c93_write_info,
        .proc_name              = "GVP11",
        .queuecommand           = wd33c93_queuecommand,
        .eh_abort_handler       = wd33c93_abort,
        .eh_host_reset_handler  = wd33c93_host_reset,
        .can_queue              = CAN_QUEUE,
        .this_id                = 7,
        .sg_tablesize           = SG_ALL,
        .cmd_per_lun            = CMD_PER_LUN,
        .dma_boundary           = PAGE_SIZE - 1,
};

static int check_wd33c93(struct gvp11_scsiregs *regs)
{
#ifdef CHECK_WD33C93
        volatile unsigned char *sasr_3393, *scmd_3393;
        unsigned char save_sasr;
        unsigned char q, qq;

        /*
         * These darn GVP boards are a problem - it can be tough to tell
         * whether or not they include a SCSI controller. This is the
         * ultimate Yet-Another-GVP-Detection-Hack in that it actually
         * probes for a WD33c93 chip: If we find one, it's extremely
         * likely that this card supports SCSI, regardless of Product_
         * Code, Board_Size, etc.
         */

        /* Get pointers to the presumed register locations and save contents */

        sasr_3393 = &regs->SASR;
        scmd_3393 = &regs->SCMD;
        save_sasr = *sasr_3393;

        /* First test the AuxStatus Reg */

        q = *sasr_3393; /* read it */
        if (q & 0x08)   /* bit 3 should always be clear */
                return -ENODEV;
        *sasr_3393 = WD_AUXILIARY_STATUS;       /* setup indirect address */
        if (*sasr_3393 == WD_AUXILIARY_STATUS) {        /* shouldn't retain the write */
                *sasr_3393 = save_sasr; /* Oops - restore this byte */
                return -ENODEV;
        }
        if (*sasr_3393 != q) {  /* should still read the same */
                *sasr_3393 = save_sasr; /* Oops - restore this byte */
                return -ENODEV;
        }
        if (*scmd_3393 != q)    /* and so should the image at 0x1f */
                return -ENODEV;

        /*
         * Ok, we probably have a wd33c93, but let's check a few other places
         * for good measure. Make sure that this works for both 'A and 'B
         * chip versions.
         */

        *sasr_3393 = WD_SCSI_STATUS;
        q = *scmd_3393;
        *sasr_3393 = WD_SCSI_STATUS;
        *scmd_3393 = ~q;
        *sasr_3393 = WD_SCSI_STATUS;
        qq = *scmd_3393;
        *sasr_3393 = WD_SCSI_STATUS;
        *scmd_3393 = q;
        if (qq != q)    /* should be read only */
                return -ENODEV;
        *sasr_3393 = 0x1e;      /* this register is unimplemented */
        q = *scmd_3393;
        *sasr_3393 = 0x1e;
        *scmd_3393 = ~q;
        *sasr_3393 = 0x1e;
        qq = *scmd_3393;
        *sasr_3393 = 0x1e;
        *scmd_3393 = q;
        if (qq != q || qq != 0xff)      /* should be read only, all 1's */
                return -ENODEV;
        *sasr_3393 = WD_TIMEOUT_PERIOD;
        q = *scmd_3393;
        *sasr_3393 = WD_TIMEOUT_PERIOD;
        *scmd_3393 = ~q;
        *sasr_3393 = WD_TIMEOUT_PERIOD;
        qq = *scmd_3393;
        *sasr_3393 = WD_TIMEOUT_PERIOD;
        *scmd_3393 = q;
        if (qq != (~q & 0xff))  /* should be read/write */
                return -ENODEV;
#endif /* CHECK_WD33C93 */

        return 0;
}

static int gvp11_probe(struct zorro_dev *z, const struct zorro_device_id *ent)
{
        struct Scsi_Host *instance;
        unsigned long address;
        int error;
        unsigned int epc;
        unsigned int default_dma_xfer_mask;
        struct gvp11_hostdata *hdata;
        struct gvp11_scsiregs *regs;
        wd33c93_regs wdregs;

        default_dma_xfer_mask = ent->driver_data;

        /*
         * Rumors state that some GVP ram boards use the same product
         * code as the SCSI controllers. Therefore if the board-size
         * is not 64KB we assume it is a ram board and bail out.
         */
        if (zorro_resource_len(z) != 0x10000)
                return -ENODEV;

        address = z->resource.start;
        if (!request_mem_region(address, 256, "wd33c93"))
                return -EBUSY;

        regs = ZTWO_VADDR(address);

        error = check_wd33c93(regs);
        if (error)
                goto fail_check_or_alloc;

        instance = scsi_host_alloc(&gvp11_scsi_template,
                                   sizeof(struct gvp11_hostdata));
        if (!instance) {
                error = -ENOMEM;
                goto fail_check_or_alloc;
        }

        instance->irq = IRQ_AMIGA_PORTS;
        instance->unique_id = z->slotaddr;

        regs->secret2 = 1;
        regs->secret1 = 0;
        regs->secret3 = 15;
        while (regs->CNTR & GVP11_DMAC_BUSY)
                ;
        regs->CNTR = 0;
        regs->BANK = 0;

        wdregs.SASR = &regs->SASR;
        wdregs.SCMD = &regs->SCMD;

        hdata = shost_priv(instance);
        if (gvp11_xfer_mask)
                hdata->wh.dma_xfer_mask = gvp11_xfer_mask;
        else
                hdata->wh.dma_xfer_mask = default_dma_xfer_mask;

        hdata->wh.no_sync = 0xff;
        hdata->wh.fast = 0;
        hdata->wh.dma_mode = CTRL_DMA;
        hdata->regs = regs;

        /*
         * Check for 14MHz SCSI clock
         */
        epc = *(unsigned short *)(ZTWO_VADDR(address) + 0x8000);
        wd33c93_init(instance, wdregs, dma_setup, dma_stop,
                     (epc & GVP_SCSICLKMASK) ? WD33C93_FS_8_10
                                             : WD33C93_FS_12_15);

        error = request_irq(IRQ_AMIGA_PORTS, gvp11_intr, IRQF_SHARED,
                            "GVP11 SCSI", instance);
        if (error)
                goto fail_irq;

        regs->CNTR = GVP11_DMAC_INT_ENABLE;

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

        zorro_set_drvdata(z, instance);
        scsi_scan_host(instance);
        return 0;

fail_host:
        free_irq(IRQ_AMIGA_PORTS, instance);
fail_irq:
        scsi_host_put(instance);
fail_check_or_alloc:
        release_mem_region(address, 256);
        return error;
}

static void gvp11_remove(struct zorro_dev *z)
{
        struct Scsi_Host *instance = zorro_get_drvdata(z);
        struct gvp11_hostdata *hdata = shost_priv(instance);

        hdata->regs->CNTR = 0;
        scsi_remove_host(instance);
        free_irq(IRQ_AMIGA_PORTS, instance);
        scsi_host_put(instance);
        release_mem_region(z->resource.start, 256);
}

        /*
         * This should (hopefully) be the correct way to identify
         * all the different GVP SCSI controllers (except for the
         * SERIES I though).
         */

static struct zorro_device_id gvp11_zorro_tbl[] = {
        { ZORRO_PROD_GVP_COMBO_030_R3_SCSI,     ~0x00ffffff },
        { ZORRO_PROD_GVP_SERIES_II,             ~0x00ffffff },
        { ZORRO_PROD_GVP_GFORCE_030_SCSI,       ~0x01ffffff },
        { ZORRO_PROD_GVP_A530_SCSI,             ~0x01ffffff },
        { ZORRO_PROD_GVP_COMBO_030_R4_SCSI,     ~0x01ffffff },
        { ZORRO_PROD_GVP_A1291,                 ~0x07ffffff },
        { ZORRO_PROD_GVP_GFORCE_040_SCSI_1,     ~0x07ffffff },
        { 0 }
};
MODULE_DEVICE_TABLE(zorro, gvp11_zorro_tbl);

static struct zorro_driver gvp11_driver = {
        .name           = "gvp11",
        .id_table       = gvp11_zorro_tbl,
        .probe          = gvp11_probe,
        .remove         = gvp11_remove,
};

static int __init gvp11_init(void)
{
        return zorro_register_driver(&gvp11_driver);
}
module_init(gvp11_init);

static void __exit gvp11_exit(void)
{
        zorro_unregister_driver(&gvp11_driver);
}
module_exit(gvp11_exit);

MODULE_DESCRIPTION("GVP Series II SCSI");
MODULE_LICENSE("GPL");