// 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/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_tcq.h>
#include "wd33c93.h"
#include "a2091.h"


struct a2091_hostdata {
        struct WD33C93_hostdata wh;
        struct a2091_scsiregs *regs;
        struct device *dev;
};

#define DMA_DIR(d)   ((d == DATA_OUT_DIR) ? DMA_TO_DEVICE : DMA_FROM_DEVICE)

static irqreturn_t a2091_intr(int irq, void *data)
{
        struct Scsi_Host *instance = data;
        struct a2091_hostdata *hdata = shost_priv(instance);
        unsigned int status = hdata->regs->ISTR;
        unsigned long flags;

        if (!(status & (ISTR_INT_F | ISTR_INT_P)) || !(status & ISTR_INTS))
                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 dma_setup(struct scsi_cmnd *cmd, int dir_in)
{
        struct scsi_pointer *scsi_pointer = WD33C93_scsi_pointer(cmd);
        unsigned long len = scsi_pointer->this_residual;
        struct Scsi_Host *instance = cmd->device->host;
        struct a2091_hostdata *hdata = shost_priv(instance);
        struct WD33C93_hostdata *wh = &hdata->wh;
        struct a2091_scsiregs *regs = hdata->regs;
        unsigned short cntr = CNTR_PDMD | CNTR_INTEN;
        dma_addr_t addr;

        addr = dma_map_single(hdata->dev, scsi_pointer->ptr,
                              len, DMA_DIR(dir_in));
        if (dma_mapping_error(hdata->dev, addr)) {
                dev_warn(hdata->dev, "cannot map SCSI data block %p\n",
                         scsi_pointer->ptr);
                return 1;
        }
        scsi_pointer->dma_handle = addr;

        /* don't allow DMA if the physical address is bad */
        if (addr & A2091_XFER_MASK) {
                /* drop useless mapping */
                dma_unmap_single(hdata->dev, scsi_pointer->dma_handle,
                                 scsi_pointer->this_residual,
                                 DMA_DIR(dir_in));
                scsi_pointer->dma_handle = (dma_addr_t) NULL;

                wh->dma_bounce_len = (scsi_pointer->this_residual + 511) & ~0x1ff;
                wh->dma_bounce_buffer = kmalloc(wh->dma_bounce_len,
                                                GFP_KERNEL);

                /* can't allocate memory; use PIO */
                if (!wh->dma_bounce_buffer) {
                        wh->dma_bounce_len = 0;
                        return 1;
                }

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

                /* will flush/invalidate cache for us */
                addr = dma_map_single(hdata->dev, wh->dma_bounce_buffer,
                                      wh->dma_bounce_len, DMA_DIR(dir_in));
                /* can't map buffer; use PIO */
                if (dma_mapping_error(hdata->dev, addr)) {
                        dev_warn(hdata->dev, "cannot map bounce buffer %p\n",
                                 wh->dma_bounce_buffer);
                        return 1;
                }

                /* the bounce buffer may not be in the first 16M of physmem */
                if (addr & A2091_XFER_MASK) {
                        /* we could use chipmem... maybe later */
                        kfree(wh->dma_bounce_buffer);
                        wh->dma_bounce_buffer = NULL;
                        wh->dma_bounce_len = 0;
                        return 1;
                }

                scsi_pointer->dma_handle = addr;
        }

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

        /* remember direction */
        wh->dma_dir = dir_in;

        regs->CNTR = cntr;

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

        /* no more cache flush here - dma_map_single() takes care */

        /* 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 scsi_pointer *scsi_pointer = WD33C93_scsi_pointer(SCpnt);
        struct a2091_hostdata *hdata = shost_priv(instance);
        struct WD33C93_hostdata *wh = &hdata->wh;
        struct a2091_scsiregs *regs = hdata->regs;

        /* disable SCSI interrupts */
        unsigned short cntr = CNTR_PDMD;

        if (!wh->dma_dir)
                cntr |= CNTR_DDIR;

        /* disable SCSI interrupts */
        regs->CNTR = cntr;

        /* flush if we were reading */
        if (wh->dma_dir) {
                regs->FLUSH = 1;
                while (!(regs->ISTR & ISTR_FE_FLG))
                        ;
        }

        /* clear a possible interrupt */
        regs->CINT = 1;

        /* stop DMA */
        regs->SP_DMA = 1;

        /* restore the CONTROL bits (minus the direction flag) */
        regs->CNTR = CNTR_PDMD | CNTR_INTEN;

        dma_unmap_single(hdata->dev, scsi_pointer->dma_handle,
                         scsi_pointer->this_residual,
                         DMA_DIR(wh->dma_dir));

        /* copy from a bounce buffer, if necessary */
        if (status && wh->dma_bounce_buffer) {
                if (wh->dma_dir)
                        memcpy(scsi_pointer->ptr, wh->dma_bounce_buffer,
                               scsi_pointer->this_residual);
                kfree(wh->dma_bounce_buffer);
                wh->dma_bounce_buffer = NULL;
                wh->dma_bounce_len = 0;
        }
}

static const struct scsi_host_template a2091_scsi_template = {
        .module                 = THIS_MODULE,
        .name                   = "Commodore A2091/A590 SCSI",
        .show_info              = wd33c93_show_info,
        .write_info             = wd33c93_write_info,
        .proc_name              = "A2901",
        .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,
        .cmd_size               = sizeof(struct scsi_pointer),
};

static int a2091_probe(struct zorro_dev *z, const struct zorro_device_id *ent)
{
        struct Scsi_Host *instance;
        int error;
        struct a2091_scsiregs *regs;
        wd33c93_regs wdregs;
        struct a2091_hostdata *hdata;

        if (dma_set_mask_and_coherent(&z->dev, DMA_BIT_MASK(24))) {
                dev_warn(&z->dev, "cannot use 24 bit DMA\n");
                return -ENODEV;
        }

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

        instance = scsi_host_alloc(&a2091_scsi_template,
                                   sizeof(struct a2091_hostdata));
        if (!instance) {
                error = -ENOMEM;
                goto fail_alloc;
        }

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

        regs = ZTWO_VADDR(z->resource.start);
        regs->DAWR = DAWR_A2091;

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

        hdata = shost_priv(instance);
        hdata->dev = &z->dev;
        hdata->wh.no_sync = 0xff;
        hdata->wh.fast = 0;
        hdata->wh.dma_mode = CTRL_DMA;
        hdata->regs = regs;

        wd33c93_init(instance, wdregs, dma_setup, dma_stop, WD33C93_FS_8_10);
        error = request_irq(IRQ_AMIGA_PORTS, a2091_intr, IRQF_SHARED,
                            "A2091 SCSI", instance);
        if (error)
                goto fail_irq;

        regs->CNTR = CNTR_PDMD | CNTR_INTEN;

        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_alloc:
        release_mem_region(z->resource.start, 256);
        return error;
}

static void a2091_remove(struct zorro_dev *z)
{
        struct Scsi_Host *instance = zorro_get_drvdata(z);
        struct a2091_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);
}

static struct zorro_device_id a2091_zorro_tbl[] = {
        { ZORRO_PROD_CBM_A590_A2091_1 },
        { ZORRO_PROD_CBM_A590_A2091_2 },
        { 0 }
};
MODULE_DEVICE_TABLE(zorro, a2091_zorro_tbl);

static struct zorro_driver a2091_driver = {
        .name           = "a2091",
        .id_table       = a2091_zorro_tbl,
        .probe          = a2091_probe,
        .remove         = a2091_remove,
};

static int __init a2091_init(void)
{
        return zorro_register_driver(&a2091_driver);
}
module_init(a2091_init);

static void __exit a2091_exit(void)
{
        zorro_unregister_driver(&a2091_driver);
}
module_exit(a2091_exit);

MODULE_DESCRIPTION("Commodore A2091/A590 SCSI");
MODULE_LICENSE("GPL");