// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/drivers/scsi/arm/arxescsi.c
 *
 * Copyright (C) 1997-2000 Russell King, Stefan Hanske
 *
 * This driver is based on experimentation.  Hence, it may have made
 * assumptions about the particular card that I have available, and
 * may not be reliable!
 *
 * Changelog:
 *  30-08-1997  RMK     0.0.0   Created, READONLY version as cumana_2.c
 *  22-01-1998  RMK     0.0.1   Updated to 2.1.80
 *  15-04-1998  RMK     0.0.1   Only do PIO if FAS216 will allow it.
 *  11-06-1998  SH      0.0.2   Changed to support ARXE 16-bit SCSI card
 *                              enabled writing
 *  01-01-2000  SH      0.1.0   Added *real* pseudo dma writing
 *                              (arxescsi_pseudo_dma_write)
 *  02-04-2000  RMK     0.1.1   Updated for new error handling code.
 *  22-10-2000  SH              Updated for new registering scheme.
 */
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/proc_fs.h>
#include <linux/unistd.h>
#include <linux/stat.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>

#include <asm/dma.h>
#include <asm/io.h>
#include <asm/ecard.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>
#include "fas216.h"

struct arxescsi_info {
        FAS216_Info             info;
        struct expansion_card   *ec;
        void __iomem            *base;
};

#define DMADATA_OFFSET  (0x200)

#define DMASTAT_OFFSET  (0x600)
#define DMASTAT_DRQ     (1 << 0)

#define CSTATUS_IRQ     (1 << 0)

#define VERSION "1.10 (23/01/2003 2.5.57)"

/*
 * Function: int arxescsi_dma_setup(host, SCpnt, direction, min_type)
 * Purpose : initialises DMA/PIO
 * Params  : host      - host
 *           SCpnt     - command
 *           direction - DMA on to/off of card
 *           min_type  - minimum DMA support that we must have for this transfer
 * Returns : 0 if we should not set CMD_WITHDMA for transfer info command
 */
static fasdmatype_t
arxescsi_dma_setup(struct Scsi_Host *host, struct scsi_pointer *SCp,
                       fasdmadir_t direction, fasdmatype_t min_type)
{
        /*
         * We don't do real DMA
         */
        return fasdma_pseudo;
}

static void arxescsi_pseudo_dma_write(unsigned char *addr, void __iomem *base)
{
       __asm__ __volatile__(
       "               stmdb   sp!, {r0-r12}\n"
       "               mov     r3, %0\n"
       "               mov     r1, %1\n"
       "               add     r2, r1, #512\n"
       "               mov     r4, #256\n"
       ".loop_1:       ldmia   r3!, {r6, r8, r10, r12}\n"
       "               mov     r5, r6, lsl #16\n"
       "               mov     r7, r8, lsl #16\n"
       ".loop_2:       ldrb    r0, [r1, #1536]\n"
       "               tst     r0, #1\n"
       "               beq     .loop_2\n"
       "               stmia   r2, {r5-r8}\n\t"
       "               mov     r9, r10, lsl #16\n"
       "               mov     r11, r12, lsl #16\n"
       ".loop_3:       ldrb    r0, [r1, #1536]\n"
       "               tst     r0, #1\n"
       "               beq     .loop_3\n"
       "               stmia   r2, {r9-r12}\n"
       "               subs    r4, r4, #16\n"
       "               bne     .loop_1\n"
       "               ldmia   sp!, {r0-r12}\n"
       :
       : "r" (addr), "r" (base));
}

/*
 * Function: int arxescsi_dma_pseudo(host, SCpnt, direction, transfer)
 * Purpose : handles pseudo DMA
 * Params  : host      - host
 *           SCpnt     - command
 *           direction - DMA on to/off of card
 *           transfer  - minimum number of bytes we expect to transfer
 */
static void
arxescsi_dma_pseudo(struct Scsi_Host *host, struct scsi_pointer *SCp,
                    fasdmadir_t direction, int transfer)
{
        struct arxescsi_info *info = (struct arxescsi_info *)host->hostdata;
        unsigned int length, error = 0;
        void __iomem *base = info->info.scsi.io_base;
        unsigned char *addr;

        length = SCp->this_residual;
        addr = SCp->ptr;

        if (direction == DMA_OUT) {
                unsigned int word;
                while (length > 256) {
                        if (readb(base + 0x80) & STAT_INT) {
                                error = 1;
                                break;
                        }
                        arxescsi_pseudo_dma_write(addr, base);
                        addr += 256;
                        length -= 256;
                }

                if (!error)
                        while (length > 0) {
                                if (readb(base + 0x80) & STAT_INT)
                                        break;
         
                                if (!(readb(base + DMASTAT_OFFSET) & DMASTAT_DRQ))
                                        continue;

                                word = *addr | *(addr + 1) << 8;

                                writew(word, base + DMADATA_OFFSET);
                                if (length > 1) {
                                        addr += 2;
                                        length -= 2;
                                } else {
                                        addr += 1;
                                        length -= 1;
                                }
                        }
        }
        else {
                if (transfer && (transfer & 255)) {
                        while (length >= 256) {
                                if (readb(base + 0x80) & STAT_INT) {
                                        error = 1;
                                        break;
                                }
            
                                if (!(readb(base + DMASTAT_OFFSET) & DMASTAT_DRQ))
                                        continue;

                                readsw(base + DMADATA_OFFSET, addr, 256 >> 1);
                                addr += 256;
                                length -= 256;
                        }
                }

                if (!(error))
                        while (length > 0) {
                                unsigned long word;

                                if (readb(base + 0x80) & STAT_INT)
                                        break;

                                if (!(readb(base + DMASTAT_OFFSET) & DMASTAT_DRQ))
                                        continue;

                                word = readw(base + DMADATA_OFFSET);
                                *addr++ = word;
                                if (--length > 0) {
                                        *addr++ = word >> 8;
                                        length --;
                                }
                        }
        }
}

/*
 * Function: int arxescsi_dma_stop(host, SCpnt)
 * Purpose : stops DMA/PIO
 * Params  : host  - host
 *           SCpnt - command
 */
static void arxescsi_dma_stop(struct Scsi_Host *host, struct scsi_pointer *SCp)
{
        /*
         * no DMA to stop
         */
}

/*
 * Function: const char *arxescsi_info(struct Scsi_Host * host)
 * Purpose : returns a descriptive string about this interface,
 * Params  : host - driver host structure to return info for.
 * Returns : pointer to a static buffer containing null terminated string.
 */
static const char *arxescsi_info(struct Scsi_Host *host)
{
        struct arxescsi_info *info = (struct arxescsi_info *)host->hostdata;
        static char string[150];

        sprintf(string, "%s (%s) in slot %d v%s",
                host->hostt->name, info->info.scsi.type, info->ec->slot_no,
                VERSION);

        return string;
}

static int
arxescsi_show_info(struct seq_file *m, struct Scsi_Host *host)
{
        struct arxescsi_info *info;
        info = (struct arxescsi_info *)host->hostdata;

        seq_printf(m, "ARXE 16-bit SCSI driver v%s\n", VERSION);
        fas216_print_host(&info->info, m);
        fas216_print_stats(&info->info, m);
        fas216_print_devices(&info->info, m);
        return 0;
}

static const struct scsi_host_template arxescsi_template = {
        .show_info                      = arxescsi_show_info,
        .name                           = "ARXE SCSI card",
        .info                           = arxescsi_info,
        .queuecommand                   = fas216_noqueue_command,
        .eh_host_reset_handler          = fas216_eh_host_reset,
        .eh_bus_reset_handler           = fas216_eh_bus_reset,
        .eh_device_reset_handler        = fas216_eh_device_reset,
        .eh_abort_handler               = fas216_eh_abort,
        .cmd_size                       = sizeof(struct fas216_cmd_priv),
        .can_queue                      = 0,
        .this_id                        = 7,
        .sg_tablesize                   = SG_ALL,
        .dma_boundary                   = PAGE_SIZE - 1,
        .proc_name                      = "arxescsi",
};

static int arxescsi_probe(struct expansion_card *ec, const struct ecard_id *id)
{
        struct Scsi_Host *host;
        struct arxescsi_info *info;
        void __iomem *base;
        int ret;

        ret = ecard_request_resources(ec);
        if (ret)
                goto out;

        base = ecardm_iomap(ec, ECARD_RES_MEMC, 0, 0);
        if (!base) {
                ret = -ENOMEM;
                goto out_region;
        }

        host = scsi_host_alloc(&arxescsi_template, sizeof(struct arxescsi_info));
        if (!host) {
                ret = -ENOMEM;
                goto out_region;
        }

        info = (struct arxescsi_info *)host->hostdata;
        info->ec = ec;
        info->base = base;

        info->info.scsi.io_base         = base + 0x2000;
        info->info.scsi.irq             = 0;
        info->info.scsi.dma             = NO_DMA;
        info->info.scsi.io_shift        = 5;
        info->info.ifcfg.clockrate      = 24; /* MHz */
        info->info.ifcfg.select_timeout = 255;
        info->info.ifcfg.asyncperiod    = 200; /* ns */
        info->info.ifcfg.sync_max_depth = 0;
        info->info.ifcfg.cntl3          = CNTL3_FASTSCSI | CNTL3_FASTCLK;
        info->info.ifcfg.disconnect_ok  = 0;
        info->info.ifcfg.wide_max_size  = 0;
        info->info.ifcfg.capabilities   = FASCAP_PSEUDODMA;
        info->info.dma.setup            = arxescsi_dma_setup;
        info->info.dma.pseudo           = arxescsi_dma_pseudo;
        info->info.dma.stop             = arxescsi_dma_stop;
                
        ec->irqaddr = base;
        ec->irqmask = CSTATUS_IRQ;

        ret = fas216_init(host);
        if (ret)
                goto out_unregister;

        ret = fas216_add(host, &ec->dev);
        if (ret == 0)
                goto out;

        fas216_release(host);
 out_unregister:
        scsi_host_put(host);
 out_region:
        ecard_release_resources(ec);
 out:
        return ret;
}

static void arxescsi_remove(struct expansion_card *ec)
{
        struct Scsi_Host *host = ecard_get_drvdata(ec);

        ecard_set_drvdata(ec, NULL);
        fas216_remove(host);

        fas216_release(host);
        scsi_host_put(host);
        ecard_release_resources(ec);
}

static const struct ecard_id arxescsi_cids[] = {
        { MANU_ARXE, PROD_ARXE_SCSI },
        { 0xffff, 0xffff },
};

static struct ecard_driver arxescsi_driver = {
        .probe          = arxescsi_probe,
        .remove         = arxescsi_remove,
        .id_table       = arxescsi_cids,
        .drv = {
                .name           = "arxescsi",
        },
};

static int __init init_arxe_scsi_driver(void)
{
        return ecard_register_driver(&arxescsi_driver);
}

static void __exit exit_arxe_scsi_driver(void)
{
        ecard_remove_driver(&arxescsi_driver);
}

module_init(init_arxe_scsi_driver);
module_exit(exit_arxe_scsi_driver);

MODULE_AUTHOR("Stefan Hanske");
MODULE_DESCRIPTION("ARXESCSI driver for Acorn machines");
MODULE_LICENSE("GPL");