/*
 * PCMCIA socket code for the Alchemy Db1xxx/Pb1xxx boards.
 *
 * Copyright (c) 2009 Manuel Lauss <manuel.lauss@gmail.com>
 *
 */

/* This is a fairly generic PCMCIA socket driver suitable for the
 * following Alchemy Development boards:
 *  Db1000, Db/Pb1500, Db/Pb1100, Db/Pb1550, Db/Pb1200, Db1300
 *
 * The Db1000 is used as a reference:  Per-socket card-, carddetect- and
 *  statuschange IRQs connected to SoC GPIOs, control and status register
 *  bits arranged in per-socket groups in an external PLD.  All boards
 *  listed here use this layout, including bit positions and meanings.
 *  Of course there are exceptions in later boards:
 *
 *      - Pb1100/Pb1500:  single socket only; voltage key bits VS are
 *                        at STATUS[5:4] (instead of STATUS[1:0]).
 *      - Au1200-based:   additional card-eject irqs, irqs not gpios!
 *      - Db1300:         Db1200-like, no pwr ctrl, single socket (#1).
 */

#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/pm.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/resource.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include <pcmcia/ss.h>

#include <asm/mach-au1x00/au1000.h>
#include <asm/mach-db1x00/bcsr.h>

#define MEM_MAP_SIZE    0x400000
#define IO_MAP_SIZE     0x1000

struct db1x_pcmcia_sock {
        struct pcmcia_socket    socket;
        int             nr;             /* socket number */
        void            *virt_io;

        phys_addr_t     phys_io;
        phys_addr_t     phys_attr;
        phys_addr_t     phys_mem;

        /* previous flags for set_socket() */
        unsigned int old_flags;

        /* interrupt sources: linux irq numbers! */
        int     insert_irq;     /* default carddetect irq */
        int     stschg_irq;     /* card-status-change irq */
        int     card_irq;       /* card irq */
        int     eject_irq;      /* db1200/pb1200 have these */

#define BOARD_TYPE_DEFAULT      0       /* most boards */
#define BOARD_TYPE_DB1200       1       /* IRQs aren't gpios */
#define BOARD_TYPE_PB1100       2       /* VS bits slightly different */
#define BOARD_TYPE_DB1300       3       /* no power control */
        int     board_type;
};

#define to_db1x_socket(x) container_of(x, struct db1x_pcmcia_sock, socket)

static int db1300_card_inserted(struct db1x_pcmcia_sock *sock)
{
        return bcsr_read(BCSR_SIGSTAT) & (1 << 8);
}

/* DB/PB1200: check CPLD SIGSTATUS register bit 10/12 */
static int db1200_card_inserted(struct db1x_pcmcia_sock *sock)
{
        unsigned short sigstat;

        sigstat = bcsr_read(BCSR_SIGSTAT);
        return sigstat & 1 << (8 + 2 * sock->nr);
}

/* carddetect gpio: low-active */
static int db1000_card_inserted(struct db1x_pcmcia_sock *sock)
{
        return !gpio_get_value(irq_to_gpio(sock->insert_irq));
}

static int db1x_card_inserted(struct db1x_pcmcia_sock *sock)
{
        switch (sock->board_type) {
        case BOARD_TYPE_DB1200:
                return db1200_card_inserted(sock);
        case BOARD_TYPE_DB1300:
                return db1300_card_inserted(sock);
        default:
                return db1000_card_inserted(sock);
        }
}

/* STSCHG tends to bounce heavily when cards are inserted/ejected.
 * To avoid this, the interrupt is normally disabled and only enabled
 * after reset to a card has been de-asserted.
 */
static inline void set_stschg(struct db1x_pcmcia_sock *sock, int en)
{
        if (sock->stschg_irq != -1) {
                if (en)
                        enable_irq(sock->stschg_irq);
                else
                        disable_irq(sock->stschg_irq);
        }
}

static irqreturn_t db1000_pcmcia_cdirq(int irq, void *data)
{
        struct db1x_pcmcia_sock *sock = data;

        pcmcia_parse_events(&sock->socket, SS_DETECT);

        return IRQ_HANDLED;
}

static irqreturn_t db1000_pcmcia_stschgirq(int irq, void *data)
{
        struct db1x_pcmcia_sock *sock = data;

        pcmcia_parse_events(&sock->socket, SS_STSCHG);

        return IRQ_HANDLED;
}

static irqreturn_t db1200_pcmcia_cdirq(int irq, void *data)
{
        struct db1x_pcmcia_sock *sock = data;

        /* Db/Pb1200 have separate per-socket insertion and ejection
         * interrupts which stay asserted as long as the card is
         * inserted/missing.  The one which caused us to be called
         * needs to be disabled and the other one enabled.
         */
        if (irq == sock->insert_irq) {
                disable_irq_nosync(sock->insert_irq);
                enable_irq(sock->eject_irq);
        } else {
                disable_irq_nosync(sock->eject_irq);
                enable_irq(sock->insert_irq);
        }

        pcmcia_parse_events(&sock->socket, SS_DETECT);

        return IRQ_HANDLED;
}

static int db1x_pcmcia_setup_irqs(struct db1x_pcmcia_sock *sock)
{
        int ret;

        if (sock->stschg_irq != -1) {
                ret = request_irq(sock->stschg_irq, db1000_pcmcia_stschgirq,
                                  0, "pcmcia_stschg", sock);
                if (ret)
                        return ret;
        }

        /* Db/Pb1200 have separate per-socket insertion and ejection
         * interrupts, which should show edge behaviour but don't.
         * So interrupts are disabled until both insertion and
         * ejection handler have been registered and the currently
         * active one disabled.
         */
        if ((sock->board_type == BOARD_TYPE_DB1200) ||
            (sock->board_type == BOARD_TYPE_DB1300)) {
                ret = request_irq(sock->insert_irq, db1200_pcmcia_cdirq,
                                  0, "pcmcia_insert", sock);
                if (ret)
                        goto out1;

                ret = request_irq(sock->eject_irq, db1200_pcmcia_cdirq,
                                  0, "pcmcia_eject", sock);
                if (ret) {
                        free_irq(sock->insert_irq, sock);
                        goto out1;
                }

                /* enable the currently silent one */
                if (db1x_card_inserted(sock))
                        enable_irq(sock->eject_irq);
                else
                        enable_irq(sock->insert_irq);
        } else {
                /* all other (older) Db1x00 boards use a GPIO to show
                 * card detection status:  use both-edge triggers.
                 */
                irq_set_irq_type(sock->insert_irq, IRQ_TYPE_EDGE_BOTH);
                ret = request_irq(sock->insert_irq, db1000_pcmcia_cdirq,
                                  0, "pcmcia_carddetect", sock);

                if (ret)
                        goto out1;
        }

        return 0;       /* all done */

out1:
        if (sock->stschg_irq != -1)
                free_irq(sock->stschg_irq, sock);

        return ret;
}

static void db1x_pcmcia_free_irqs(struct db1x_pcmcia_sock *sock)
{
        if (sock->stschg_irq != -1)
                free_irq(sock->stschg_irq, sock);

        free_irq(sock->insert_irq, sock);
        if (sock->eject_irq != -1)
                free_irq(sock->eject_irq, sock);
}

/*
 * configure a PCMCIA socket on the Db1x00 series of boards (and
 * compatibles).
 *
 * 2 external registers are involved:
 *   pcmcia_status (offset 0x04): bits [0:1/2:3]: read card voltage id
 *   pcmcia_control(offset 0x10):
 *      bits[0:1] set vcc for card
 *      bits[2:3] set vpp for card
 *      bit 4:  enable data buffers
 *      bit 7:  reset# for card
 *      add 8 for second socket.
 */
static int db1x_pcmcia_configure(struct pcmcia_socket *skt,
                                 struct socket_state_t *state)
{
        struct db1x_pcmcia_sock *sock = to_db1x_socket(skt);
        unsigned short cr_clr, cr_set;
        unsigned int changed;
        int v, p, ret;

        /* card voltage setup */
        cr_clr = (0xf << (sock->nr * 8)); /* clear voltage settings */
        cr_set = 0;
        v = p = ret = 0;

        switch (state->Vcc) {
        case 50:
                ++v;
        case 33:
                ++v;
        case 0:
                break;
        default:
                printk(KERN_INFO "pcmcia%d unsupported Vcc %d\n",
                        sock->nr, state->Vcc);
        }

        switch (state->Vpp) {
        case 12:
                ++p;
        case 33:
        case 50:
                ++p;
        case 0:
                break;
        default:
                printk(KERN_INFO "pcmcia%d unsupported Vpp %d\n",
                        sock->nr, state->Vpp);
        }

        /* sanity check: Vpp must be 0, 12, or Vcc */
        if (((state->Vcc == 33) && (state->Vpp == 50)) ||
            ((state->Vcc == 50) && (state->Vpp == 33))) {
                printk(KERN_INFO "pcmcia%d bad Vcc/Vpp combo (%d %d)\n",
                        sock->nr, state->Vcc, state->Vpp);
                v = p = 0;
                ret = -EINVAL;
        }

        /* create new voltage code */
        if (sock->board_type != BOARD_TYPE_DB1300)
                cr_set |= ((v << 2) | p) << (sock->nr * 8);

        changed = state->flags ^ sock->old_flags;

        if (changed & SS_RESET) {
                if (state->flags & SS_RESET) {
                        set_stschg(sock, 0);
                        /* assert reset, disable io buffers */
                        cr_clr |= (1 << (7 + (sock->nr * 8)));
                        cr_clr |= (1 << (4 + (sock->nr * 8)));
                } else {
                        /* de-assert reset, enable io buffers */
                        cr_set |= 1 << (7 + (sock->nr * 8));
                        cr_set |= 1 << (4 + (sock->nr * 8));
                }
        }

        /* update PCMCIA configuration */
        bcsr_mod(BCSR_PCMCIA, cr_clr, cr_set);

        sock->old_flags = state->flags;

        /* reset was taken away: give card time to initialize properly */
        if ((changed & SS_RESET) && !(state->flags & SS_RESET)) {
                msleep(500);
                set_stschg(sock, 1);
        }

        return ret;
}

/* VCC bits at [3:2]/[11:10] */
#define GET_VCC(cr, socknr)             \
        ((((cr) >> 2) >> ((socknr) * 8)) & 3)

/* VS bits at [0:1]/[3:2] */
#define GET_VS(sr, socknr)              \
        (((sr) >> (2 * (socknr))) & 3)

/* reset bits at [7]/[15] */
#define GET_RESET(cr, socknr)           \
        ((cr) & (1 << (7 + (8 * (socknr)))))

static int db1x_pcmcia_get_status(struct pcmcia_socket *skt,
                                  unsigned int *value)
{
        struct db1x_pcmcia_sock *sock = to_db1x_socket(skt);
        unsigned short cr, sr;
        unsigned int status;

        status = db1x_card_inserted(sock) ? SS_DETECT : 0;

        cr = bcsr_read(BCSR_PCMCIA);
        sr = bcsr_read(BCSR_STATUS);

        /* PB1100/PB1500: voltage key bits are at [5:4] */
        if (sock->board_type == BOARD_TYPE_PB1100)
                sr >>= 4;

        /* determine card type */
        switch (GET_VS(sr, sock->nr)) {
        case 0:
        case 2:
                status |= SS_3VCARD;    /* 3V card */
        case 3:
                break;                  /* 5V card: set nothing */
        default:
                status |= SS_XVCARD;    /* treated as unsupported in core */
        }

        /* if Vcc is not zero, we have applied power to a card */
        status |= GET_VCC(cr, sock->nr) ? SS_POWERON : 0;

        /* DB1300: power always on, but don't tell when no card present */
        if ((sock->board_type == BOARD_TYPE_DB1300) && (status & SS_DETECT))
                status = SS_POWERON | SS_3VCARD | SS_DETECT;

        /* reset de-asserted? then we're ready */
        status |= (GET_RESET(cr, sock->nr)) ? SS_READY : SS_RESET;

        *value = status;

        return 0;
}

static int db1x_pcmcia_sock_init(struct pcmcia_socket *skt)
{
        return 0;
}

static int db1x_pcmcia_sock_suspend(struct pcmcia_socket *skt)
{
        return 0;
}

static int au1x00_pcmcia_set_io_map(struct pcmcia_socket *skt,
                                    struct pccard_io_map *map)
{
        struct db1x_pcmcia_sock *sock = to_db1x_socket(skt);

        map->start = (u32)sock->virt_io;
        map->stop = map->start + IO_MAP_SIZE;

        return 0;
}

static int au1x00_pcmcia_set_mem_map(struct pcmcia_socket *skt,
                                     struct pccard_mem_map *map)
{
        struct db1x_pcmcia_sock *sock = to_db1x_socket(skt);

        if (map->flags & MAP_ATTRIB)
                map->static_start = sock->phys_attr + map->card_start;
        else
                map->static_start = sock->phys_mem + map->card_start;

        return 0;
}

static struct pccard_operations db1x_pcmcia_operations = {
        .init                   = db1x_pcmcia_sock_init,
        .suspend                = db1x_pcmcia_sock_suspend,
        .get_status             = db1x_pcmcia_get_status,
        .set_socket             = db1x_pcmcia_configure,
        .set_io_map             = au1x00_pcmcia_set_io_map,
        .set_mem_map            = au1x00_pcmcia_set_mem_map,
};

static int db1x_pcmcia_socket_probe(struct platform_device *pdev)
{
        struct db1x_pcmcia_sock *sock;
        struct resource *r;
        int ret, bid;

        sock = kzalloc(sizeof(struct db1x_pcmcia_sock), GFP_KERNEL);
        if (!sock)
                return -ENOMEM;

        sock->nr = pdev->id;

        bid = BCSR_WHOAMI_BOARD(bcsr_read(BCSR_WHOAMI));
        switch (bid) {
        case BCSR_WHOAMI_PB1500:
        case BCSR_WHOAMI_PB1500R2:
        case BCSR_WHOAMI_PB1100:
                sock->board_type = BOARD_TYPE_PB1100;
                break;
        case BCSR_WHOAMI_DB1000 ... BCSR_WHOAMI_PB1550_SDR:
                sock->board_type = BOARD_TYPE_DEFAULT;
                break;
        case BCSR_WHOAMI_PB1200 ... BCSR_WHOAMI_DB1200:
                sock->board_type = BOARD_TYPE_DB1200;
                break;
        case BCSR_WHOAMI_DB1300:
                sock->board_type = BOARD_TYPE_DB1300;
                break;
        default:
                printk(KERN_INFO "db1xxx-ss: unknown board %d!\n", bid);
                ret = -ENODEV;
                goto out0;
        };

        /*
         * gather resources necessary and optional nice-to-haves to
         * operate a socket:
         * This includes IRQs for Carddetection/ejection, the card
         *  itself and optional status change detection.
         * Also, the memory areas covered by a socket.  For these
         *  we require the real 36bit addresses (see the au1000.h
         *  header for more information).
         */

        /* card: irq assigned to the card itself. */
        r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "card");
        sock->card_irq = r ? r->start : 0;

        /* insert: irq which triggers on card insertion/ejection */
        r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "insert");
        sock->insert_irq = r ? r->start : -1;

        /* stschg: irq which trigger on card status change (optional) */
        r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "stschg");
        sock->stschg_irq = r ? r->start : -1;

        /* eject: irq which triggers on ejection (DB1200/PB1200 only) */
        r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "eject");
        sock->eject_irq = r ? r->start : -1;

        ret = -ENODEV;

        /* 36bit PCMCIA Attribute area address */
        r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcmcia-attr");
        if (!r) {
                printk(KERN_ERR "pcmcia%d has no 'pseudo-attr' resource!\n",
                        sock->nr);
                goto out0;
        }
        sock->phys_attr = r->start;

        /* 36bit PCMCIA Memory area address */
        r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcmcia-mem");
        if (!r) {
                printk(KERN_ERR "pcmcia%d has no 'pseudo-mem' resource!\n",
                        sock->nr);
                goto out0;
        }
        sock->phys_mem = r->start;

        /* 36bit PCMCIA IO area address */
        r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcmcia-io");
        if (!r) {
                printk(KERN_ERR "pcmcia%d has no 'pseudo-io' resource!\n",
                        sock->nr);
                goto out0;
        }
        sock->phys_io = r->start;

        /*
         * PCMCIA client drivers use the inb/outb macros to access
         * the IO registers.  Since mips_io_port_base is added
         * to the access address of the mips implementation of
         * inb/outb, we need to subtract it here because we want
         * to access the I/O or MEM address directly, without
         * going through this "mips_io_port_base" mechanism.
         */
        sock->virt_io = (void *)(ioremap(sock->phys_io, IO_MAP_SIZE) -
                                 mips_io_port_base);

        if (!sock->virt_io) {
                printk(KERN_ERR "pcmcia%d: cannot remap IO area\n",
                        sock->nr);
                ret = -ENOMEM;
                goto out0;
        }

        sock->socket.ops        = &db1x_pcmcia_operations;
        sock->socket.owner      = THIS_MODULE;
        sock->socket.pci_irq    = sock->card_irq;
        sock->socket.features   = SS_CAP_STATIC_MAP | SS_CAP_PCCARD;
        sock->socket.map_size   = MEM_MAP_SIZE;
        sock->socket.io_offset  = (unsigned long)sock->virt_io;
        sock->socket.dev.parent = &pdev->dev;
        sock->socket.resource_ops = &pccard_static_ops;

        platform_set_drvdata(pdev, sock);

        ret = db1x_pcmcia_setup_irqs(sock);
        if (ret) {
                printk(KERN_ERR "pcmcia%d cannot setup interrupts\n",
                        sock->nr);
                goto out1;
        }

        set_stschg(sock, 0);

        ret = pcmcia_register_socket(&sock->socket);
        if (ret) {
                printk(KERN_ERR "pcmcia%d failed to register\n", sock->nr);
                goto out2;
        }

        printk(KERN_INFO "Alchemy Db/Pb1xxx pcmcia%d @ io/attr/mem %09llx"
                "(%p) %09llx %09llx  card/insert/stschg/eject irqs @ %d "
                "%d %d %d\n", sock->nr, sock->phys_io, sock->virt_io,
                sock->phys_attr, sock->phys_mem, sock->card_irq,
                sock->insert_irq, sock->stschg_irq, sock->eject_irq);

        return 0;

out2:
        db1x_pcmcia_free_irqs(sock);
out1:
        iounmap((void *)(sock->virt_io + (u32)mips_io_port_base));
out0:
        kfree(sock);
        return ret;
}

static int db1x_pcmcia_socket_remove(struct platform_device *pdev)
{
        struct db1x_pcmcia_sock *sock = platform_get_drvdata(pdev);

        db1x_pcmcia_free_irqs(sock);
        pcmcia_unregister_socket(&sock->socket);
        iounmap((void *)(sock->virt_io + (u32)mips_io_port_base));
        kfree(sock);

        return 0;
}

static struct platform_driver db1x_pcmcia_socket_driver = {
        .driver = {
                .name   = "db1xxx_pcmcia",
        },
        .probe          = db1x_pcmcia_socket_probe,
        .remove         = db1x_pcmcia_socket_remove,
};

module_platform_driver(db1x_pcmcia_socket_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("PCMCIA Socket Services for Alchemy Db/Pb1x00 boards");
MODULE_AUTHOR("Manuel Lauss");