// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/gfp.h>
#include <scsi/scsi_host.h>
#include <linux/ata.h>
#include <linux/libata.h>

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

#define DRV_NAME        "pata_icside"

#define ICS_IDENT_OFFSET                0x2280

#define ICS_ARCIN_V5_INTRSTAT           0x0000
#define ICS_ARCIN_V5_INTROFFSET         0x0004

#define ICS_ARCIN_V6_INTROFFSET_1       0x2200
#define ICS_ARCIN_V6_INTRSTAT_1         0x2290
#define ICS_ARCIN_V6_INTROFFSET_2       0x3200
#define ICS_ARCIN_V6_INTRSTAT_2         0x3290

struct portinfo {
        unsigned int dataoffset;
        unsigned int ctrloffset;
        unsigned int stepping;
};

static const struct portinfo pata_icside_portinfo_v5 = {
        .dataoffset     = 0x2800,
        .ctrloffset     = 0x2b80,
        .stepping       = 6,
};

static const struct portinfo pata_icside_portinfo_v6_1 = {
        .dataoffset     = 0x2000,
        .ctrloffset     = 0x2380,
        .stepping       = 6,
};

static const struct portinfo pata_icside_portinfo_v6_2 = {
        .dataoffset     = 0x3000,
        .ctrloffset     = 0x3380,
        .stepping       = 6,
};

struct pata_icside_state {
        void __iomem *irq_port;
        void __iomem *ioc_base;
        unsigned int type;
        unsigned int dma;
        struct {
                u8 port_sel;
                u8 disabled;
                unsigned int speed[ATA_MAX_DEVICES];
        } port[2];
};

struct pata_icside_info {
        struct pata_icside_state *state;
        struct expansion_card   *ec;
        void __iomem            *base;
        void __iomem            *irqaddr;
        unsigned int            irqmask;
        const expansioncard_ops_t *irqops;
        unsigned int            mwdma_mask;
        unsigned int            nr_ports;
        const struct portinfo   *port[2];
        unsigned long           raw_base;
        unsigned long           raw_ioc_base;
};

#define ICS_TYPE_A3IN   0
#define ICS_TYPE_A3USER 1
#define ICS_TYPE_V6     3
#define ICS_TYPE_V5     15
#define ICS_TYPE_NOTYPE ((unsigned int)-1)

/* ---------------- Version 5 PCB Support Functions --------------------- */
/* Prototype: pata_icside_irqenable_arcin_v5 (struct expansion_card *ec, int irqnr)
 * Purpose  : enable interrupts from card
 */
static void pata_icside_irqenable_arcin_v5 (struct expansion_card *ec, int irqnr)
{
        struct pata_icside_state *state = ec->irq_data;

        writeb(0, state->irq_port + ICS_ARCIN_V5_INTROFFSET);
}

/* Prototype: pata_icside_irqdisable_arcin_v5 (struct expansion_card *ec, int irqnr)
 * Purpose  : disable interrupts from card
 */
static void pata_icside_irqdisable_arcin_v5 (struct expansion_card *ec, int irqnr)
{
        struct pata_icside_state *state = ec->irq_data;

        readb(state->irq_port + ICS_ARCIN_V5_INTROFFSET);
}

static const expansioncard_ops_t pata_icside_ops_arcin_v5 = {
        .irqenable      = pata_icside_irqenable_arcin_v5,
        .irqdisable     = pata_icside_irqdisable_arcin_v5,
};


/* ---------------- Version 6 PCB Support Functions --------------------- */
/* Prototype: pata_icside_irqenable_arcin_v6 (struct expansion_card *ec, int irqnr)
 * Purpose  : enable interrupts from card
 */
static void pata_icside_irqenable_arcin_v6 (struct expansion_card *ec, int irqnr)
{
        struct pata_icside_state *state = ec->irq_data;
        void __iomem *base = state->irq_port;

        if (!state->port[0].disabled)
                writeb(0, base + ICS_ARCIN_V6_INTROFFSET_1);
        if (!state->port[1].disabled)
                writeb(0, base + ICS_ARCIN_V6_INTROFFSET_2);
}

/* Prototype: pata_icside_irqdisable_arcin_v6 (struct expansion_card *ec, int irqnr)
 * Purpose  : disable interrupts from card
 */
static void pata_icside_irqdisable_arcin_v6 (struct expansion_card *ec, int irqnr)
{
        struct pata_icside_state *state = ec->irq_data;

        readb(state->irq_port + ICS_ARCIN_V6_INTROFFSET_1);
        readb(state->irq_port + ICS_ARCIN_V6_INTROFFSET_2);
}

/* Prototype: pata_icside_irqprobe(struct expansion_card *ec)
 * Purpose  : detect an active interrupt from card
 */
static int pata_icside_irqpending_arcin_v6(struct expansion_card *ec)
{
        struct pata_icside_state *state = ec->irq_data;

        return readb(state->irq_port + ICS_ARCIN_V6_INTRSTAT_1) & 1 ||
               readb(state->irq_port + ICS_ARCIN_V6_INTRSTAT_2) & 1;
}

static const expansioncard_ops_t pata_icside_ops_arcin_v6 = {
        .irqenable      = pata_icside_irqenable_arcin_v6,
        .irqdisable     = pata_icside_irqdisable_arcin_v6,
        .irqpending     = pata_icside_irqpending_arcin_v6,
};


/*
 * SG-DMA support.
 *
 * Similar to the BM-DMA, but we use the RiscPCs IOMD DMA controllers.
 * There is only one DMA controller per card, which means that only
 * one drive can be accessed at one time.  NOTE! We do not enforce that
 * here, but we rely on the main IDE driver spotting that both
 * interfaces use the same IRQ, which should guarantee this.
 */

/*
 * Configure the IOMD to give the appropriate timings for the transfer
 * mode being requested.  We take the advice of the ATA standards, and
 * calculate the cycle time based on the transfer mode, and the EIDE
 * MW DMA specs that the drive provides in the IDENTIFY command.
 *
 * We have the following IOMD DMA modes to choose from:
 *
 *      Type    Active          Recovery        Cycle
 *      A       250 (250)       312 (550)       562 (800)
 *      B       187 (200)       250 (550)       437 (750)
 *      C       125 (125)       125 (375)       250 (500)
 *      D       62  (50)        125 (375)       187 (425)
 *
 * (figures in brackets are actual measured timings on DIOR/DIOW)
 *
 * However, we also need to take care of the read/write active and
 * recovery timings:
 *
 *                      Read    Write
 *      Mode    Active  -- Recovery --  Cycle   IOMD type
 *      MW0     215     50      215     480     A
 *      MW1     80      50      50      150     C
 *      MW2     70      25      25      120     C
 */
static void pata_icside_set_dmamode(struct ata_port *ap, struct ata_device *adev)
{
        struct pata_icside_state *state = ap->host->private_data;
        struct ata_timing t;
        unsigned int cycle;
        char iomd_type;

        /*
         * DMA is based on a 16MHz clock
         */
        if (ata_timing_compute(adev, adev->dma_mode, &t, 1000, 1))
                return;

        /*
         * Choose the IOMD cycle timing which ensure that the interface
         * satisfies the measured active, recovery and cycle times.
         */
        if (t.active <= 50 && t.recover <= 375 && t.cycle <= 425) {
                iomd_type = 'D';
                cycle = 187;
        } else if (t.active <= 125 && t.recover <= 375 && t.cycle <= 500) {
                iomd_type = 'C';
                cycle = 250;
        } else if (t.active <= 200 && t.recover <= 550 && t.cycle <= 750) {
                iomd_type = 'B';
                cycle = 437;
        } else {
                iomd_type = 'A';
                cycle = 562;
        }

        ata_dev_info(adev, "timings: act %dns rec %dns cyc %dns (%c)\n",
                     t.active, t.recover, t.cycle, iomd_type);

        state->port[ap->port_no].speed[adev->devno] = cycle;
}

static void pata_icside_bmdma_setup(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct pata_icside_state *state = ap->host->private_data;
        unsigned int write = qc->tf.flags & ATA_TFLAG_WRITE;

        /*
         * We are simplex; BUG if we try to fiddle with DMA
         * while it's active.
         */
        BUG_ON(dma_channel_active(state->dma));

        /*
         * Route the DMA signals to the correct interface
         */
        writeb(state->port[ap->port_no].port_sel, state->ioc_base);

        set_dma_speed(state->dma, state->port[ap->port_no].speed[qc->dev->devno]);
        set_dma_sg(state->dma, qc->sg, qc->n_elem);
        set_dma_mode(state->dma, write ? DMA_MODE_WRITE : DMA_MODE_READ);

        /* issue r/w command */
        ap->ops->sff_exec_command(ap, &qc->tf);
}

static void pata_icside_bmdma_start(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct pata_icside_state *state = ap->host->private_data;

        BUG_ON(dma_channel_active(state->dma));
        enable_dma(state->dma);
}

static void pata_icside_bmdma_stop(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct pata_icside_state *state = ap->host->private_data;

        disable_dma(state->dma);

        /* see ata_bmdma_stop */
        ata_sff_dma_pause(ap);
}

static u8 pata_icside_bmdma_status(struct ata_port *ap)
{
        struct pata_icside_state *state = ap->host->private_data;
        void __iomem *irq_port;

        irq_port = state->irq_port + (ap->port_no ? ICS_ARCIN_V6_INTRSTAT_2 :
                                                    ICS_ARCIN_V6_INTRSTAT_1);

        return readb(irq_port) & 1 ? ATA_DMA_INTR : 0;
}

static int icside_dma_init(struct pata_icside_info *info)
{
        struct pata_icside_state *state = info->state;
        struct expansion_card *ec = info->ec;
        int i;

        for (i = 0; i < ATA_MAX_DEVICES; i++) {
                state->port[0].speed[i] = 480;
                state->port[1].speed[i] = 480;
        }

        if (ec->dma != NO_DMA && !request_dma(ec->dma, DRV_NAME)) {
                state->dma = ec->dma;
                info->mwdma_mask = ATA_MWDMA2;
        }

        return 0;
}


static const struct scsi_host_template pata_icside_sht = {
        ATA_BASE_SHT(DRV_NAME),
        .sg_tablesize           = SG_MAX_SEGMENTS,
        .dma_boundary           = IOMD_DMA_BOUNDARY,
};

static void pata_icside_postreset(struct ata_link *link, unsigned int *classes)
{
        struct ata_port *ap = link->ap;
        struct pata_icside_state *state = ap->host->private_data;

        if (classes[0] != ATA_DEV_NONE || classes[1] != ATA_DEV_NONE)
                return ata_sff_postreset(link, classes);

        state->port[ap->port_no].disabled = 1;

        if (state->type == ICS_TYPE_V6) {
                /*
                 * Disable interrupts from this port, otherwise we
                 * receive spurious interrupts from the floating
                 * interrupt line.
                 */
                void __iomem *irq_port = state->irq_port +
                                (ap->port_no ? ICS_ARCIN_V6_INTROFFSET_2 : ICS_ARCIN_V6_INTROFFSET_1);
                readb(irq_port);
        }
}

static struct ata_port_operations pata_icside_port_ops = {
        .inherits               = &ata_bmdma_port_ops,
        .sff_data_xfer          = ata_sff_data_xfer32,
        .bmdma_setup            = pata_icside_bmdma_setup,
        .bmdma_start            = pata_icside_bmdma_start,
        .bmdma_stop             = pata_icside_bmdma_stop,
        .bmdma_status           = pata_icside_bmdma_status,

        .cable_detect           = ata_cable_40wire,
        .set_dmamode            = pata_icside_set_dmamode,
        .reset.postreset        = pata_icside_postreset,

        .port_start             = ATA_OP_NULL,  /* don't need PRD table */
};

static void pata_icside_setup_ioaddr(struct ata_port *ap, void __iomem *base,
                                     struct pata_icside_info *info,
                                     const struct portinfo *port)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;
        void __iomem *cmd = base + port->dataoffset;

        ioaddr->cmd_addr        = cmd;
        ioaddr->data_addr       = cmd + (ATA_REG_DATA    << port->stepping);
        ioaddr->error_addr      = cmd + (ATA_REG_ERR     << port->stepping);
        ioaddr->feature_addr    = cmd + (ATA_REG_FEATURE << port->stepping);
        ioaddr->nsect_addr      = cmd + (ATA_REG_NSECT   << port->stepping);
        ioaddr->lbal_addr       = cmd + (ATA_REG_LBAL    << port->stepping);
        ioaddr->lbam_addr       = cmd + (ATA_REG_LBAM    << port->stepping);
        ioaddr->lbah_addr       = cmd + (ATA_REG_LBAH    << port->stepping);
        ioaddr->device_addr     = cmd + (ATA_REG_DEVICE  << port->stepping);
        ioaddr->status_addr     = cmd + (ATA_REG_STATUS  << port->stepping);
        ioaddr->command_addr    = cmd + (ATA_REG_CMD     << port->stepping);

        ioaddr->ctl_addr        = base + port->ctrloffset;
        ioaddr->altstatus_addr  = ioaddr->ctl_addr;

        ata_port_desc(ap, "cmd 0x%lx ctl 0x%lx",
                      info->raw_base + port->dataoffset,
                      info->raw_base + port->ctrloffset);

        if (info->raw_ioc_base)
                ata_port_desc(ap, "iocbase 0x%lx", info->raw_ioc_base);
}

static int pata_icside_register_v5(struct pata_icside_info *info)
{
        struct pata_icside_state *state = info->state;
        void __iomem *base;

        base = ecardm_iomap(info->ec, ECARD_RES_MEMC, 0, 0);
        if (!base)
                return -ENOMEM;

        state->irq_port = base;

        info->base = base;
        info->irqaddr = base + ICS_ARCIN_V5_INTRSTAT;
        info->irqmask = 1;
        info->irqops = &pata_icside_ops_arcin_v5;
        info->nr_ports = 1;
        info->port[0] = &pata_icside_portinfo_v5;

        info->raw_base = ecard_resource_start(info->ec, ECARD_RES_MEMC);

        return 0;
}

static int pata_icside_register_v6(struct pata_icside_info *info)
{
        struct pata_icside_state *state = info->state;
        struct expansion_card *ec = info->ec;
        void __iomem *ioc_base, *easi_base;
        unsigned int sel = 0;

        ioc_base = ecardm_iomap(ec, ECARD_RES_IOCFAST, 0, 0);
        if (!ioc_base)
                return -ENOMEM;

        easi_base = ioc_base;

        if (ecard_resource_flags(ec, ECARD_RES_EASI)) {
                easi_base = ecardm_iomap(ec, ECARD_RES_EASI, 0, 0);
                if (!easi_base)
                        return -ENOMEM;

                /*
                 * Enable access to the EASI region.
                 */
                sel = 1 << 5;
        }

        writeb(sel, ioc_base);

        state->irq_port = easi_base;
        state->ioc_base = ioc_base;
        state->port[0].port_sel = sel;
        state->port[1].port_sel = sel | 1;

        info->base = easi_base;
        info->irqops = &pata_icside_ops_arcin_v6;
        info->nr_ports = 2;
        info->port[0] = &pata_icside_portinfo_v6_1;
        info->port[1] = &pata_icside_portinfo_v6_2;

        info->raw_base = ecard_resource_start(ec, ECARD_RES_EASI);
        info->raw_ioc_base = ecard_resource_start(ec, ECARD_RES_IOCFAST);

        return icside_dma_init(info);
}

static int pata_icside_add_ports(struct pata_icside_info *info)
{
        struct expansion_card *ec = info->ec;
        struct ata_host *host;
        int i;

        if (info->irqaddr) {
                ec->irqaddr = info->irqaddr;
                ec->irqmask = info->irqmask;
        }
        if (info->irqops)
                ecard_setirq(ec, info->irqops, info->state);

        /*
         * Be on the safe side - disable interrupts
         */
        ec->ops->irqdisable(ec, ec->irq);

        host = ata_host_alloc(&ec->dev, info->nr_ports);
        if (!host)
                return -ENOMEM;

        host->private_data = info->state;
        host->flags = ATA_HOST_SIMPLEX;

        for (i = 0; i < info->nr_ports; i++) {
                struct ata_port *ap = host->ports[i];

                ap->pio_mask = ATA_PIO4;
                ap->mwdma_mask = info->mwdma_mask;
                ap->flags |= ATA_FLAG_SLAVE_POSS;
                ap->ops = &pata_icside_port_ops;

                pata_icside_setup_ioaddr(ap, info->base, info, info->port[i]);
        }

        return ata_host_activate(host, ec->irq, ata_bmdma_interrupt, 0,
                                 &pata_icside_sht);
}

static int pata_icside_probe(struct expansion_card *ec,
                             const struct ecard_id *id)
{
        struct pata_icside_state *state;
        struct pata_icside_info info;
        void __iomem *idmem;
        int ret;

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

        state = devm_kzalloc(&ec->dev, sizeof(*state), GFP_KERNEL);
        if (!state) {
                ret = -ENOMEM;
                goto release;
        }

        state->type = ICS_TYPE_NOTYPE;
        state->dma = NO_DMA;

        idmem = ecardm_iomap(ec, ECARD_RES_IOCFAST, 0, 0);
        if (idmem) {
                unsigned int type;

                type = readb(idmem + ICS_IDENT_OFFSET) & 1;
                type |= (readb(idmem + ICS_IDENT_OFFSET + 4) & 1) << 1;
                type |= (readb(idmem + ICS_IDENT_OFFSET + 8) & 1) << 2;
                type |= (readb(idmem + ICS_IDENT_OFFSET + 12) & 1) << 3;
                ecardm_iounmap(ec, idmem);

                state->type = type;
        }

        memset(&info, 0, sizeof(info));
        info.state = state;
        info.ec = ec;

        switch (state->type) {
        case ICS_TYPE_A3IN:
                dev_warn(&ec->dev, "A3IN unsupported\n");
                ret = -ENODEV;
                break;

        case ICS_TYPE_A3USER:
                dev_warn(&ec->dev, "A3USER unsupported\n");
                ret = -ENODEV;
                break;

        case ICS_TYPE_V5:
                ret = pata_icside_register_v5(&info);
                break;

        case ICS_TYPE_V6:
                ret = pata_icside_register_v6(&info);
                break;

        default:
                dev_warn(&ec->dev, "unknown interface type\n");
                ret = -ENODEV;
                break;
        }

        if (ret == 0)
                ret = pata_icside_add_ports(&info);

        if (ret == 0)
                goto out;

 release:
        ecard_release_resources(ec);
 out:
        return ret;
}

static void pata_icside_shutdown(struct expansion_card *ec)
{
        struct ata_host *host = ecard_get_drvdata(ec);
        unsigned long flags;

        /*
         * Disable interrupts from this card.  We need to do
         * this before disabling EASI since we may be accessing
         * this register via that region.
         */
        local_irq_save(flags);
        ec->ops->irqdisable(ec, ec->irq);
        local_irq_restore(flags);

        /*
         * Reset the ROM pointer so that we can read the ROM
         * after a soft reboot.  This also disables access to
         * the IDE taskfile via the EASI region.
         */
        if (host) {
                struct pata_icside_state *state = host->private_data;
                if (state->ioc_base)
                        writeb(0, state->ioc_base);
        }
}

static void pata_icside_remove(struct expansion_card *ec)
{
        struct ata_host *host = ecard_get_drvdata(ec);
        struct pata_icside_state *state = host->private_data;

        ata_host_detach(host);

        pata_icside_shutdown(ec);

        /*
         * don't NULL out the drvdata - devres/libata wants it
         * to free the ata_host structure.
         */
        if (state->dma != NO_DMA)
                free_dma(state->dma);

        ecard_release_resources(ec);
}

static const struct ecard_id pata_icside_ids[] = {
        { MANU_ICS,  PROD_ICS_IDE  },
        { MANU_ICS2, PROD_ICS2_IDE },
        { 0xffff, 0xffff }
};

static struct ecard_driver pata_icside_driver = {
        .probe          = pata_icside_probe,
        .remove         = pata_icside_remove,
        .shutdown       = pata_icside_shutdown,
        .id_table       = pata_icside_ids,
        .drv = {
                .name   = DRV_NAME,
        },
};

static int __init pata_icside_init(void)
{
        return ecard_register_driver(&pata_icside_driver);
}

static void __exit pata_icside_exit(void)
{
        ecard_remove_driver(&pata_icside_driver);
}

MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ICS PATA driver");

module_init(pata_icside_init);
module_exit(pata_icside_exit);