// SPDX-License-Identifier: GPL-2.0
/*
 * pcl816.c
 * Comedi driver for Advantech PCL-816 cards
 *
 * Author:  Juan Grigera <juan@grigera.com.ar>
 * based on pcl818 by Michal Dobes <dobes@tesnet.cz> and bits of pcl812
 */

/*
 * Driver: pcl816
 * Description: Advantech PCL-816 cards, PCL-814
 * Devices: [Advantech] PCL-816 (pcl816), PCL-814B (pcl814b)
 * Author: Juan Grigera <juan@grigera.com.ar>
 * Status: works
 * Updated: Tue,  2 Apr 2002 23:15:21 -0800
 *
 * PCL 816 and 814B have 16 SE/DIFF ADCs, 16 DACs, 16 DI and 16 DO.
 * Differences are at resolution (16 vs 12 bits).
 *
 * The driver support AI command mode, other subdevices not written.
 *
 * Analog output and digital input and output are not supported.
 *
 * Configuration Options:
 *   [0] - IO Base
 *   [1] - IRQ  (0=disable, 2, 3, 4, 5, 6, 7)
 *   [2] - DMA  (0=disable, 1, 3)
 *   [3] - 0, 10=10MHz clock for 8254
 *             1= 1MHz clock for 8254
 */

#include <linux/module.h>
#include <linux/gfp.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/comedi/comedidev.h>
#include <linux/comedi/comedi_8254.h>
#include <linux/comedi/comedi_isadma.h>

/*
 * Register I/O map
 */
#define PCL816_DO_DI_LSB_REG                    0x00
#define PCL816_DO_DI_MSB_REG                    0x01
#define PCL816_TIMER_BASE                       0x04
#define PCL816_AI_LSB_REG                       0x08
#define PCL816_AI_MSB_REG                       0x09
#define PCL816_RANGE_REG                        0x09
#define PCL816_CLRINT_REG                       0x0a
#define PCL816_MUX_REG                          0x0b
#define PCL816_MUX_SCAN(_first, _last)          (((_last) << 4) | (_first))
#define PCL816_CTRL_REG                         0x0c
#define PCL816_CTRL_SOFT_TRIG                   BIT(0)
#define PCL816_CTRL_PACER_TRIG                  BIT(1)
#define PCL816_CTRL_EXT_TRIG                    BIT(2)
#define PCL816_CTRL_POE                         BIT(3)
#define PCL816_CTRL_DMAEN                       BIT(4)
#define PCL816_CTRL_INTEN                       BIT(5)
#define PCL816_CTRL_DMASRC_SLOT(x)              (((x) & 0x3) << 6)
#define PCL816_STATUS_REG                       0x0d
#define PCL816_STATUS_NEXT_CHAN_MASK            (0xf << 0)
#define PCL816_STATUS_INTSRC_SLOT(x)            (((x) & 0x3) << 4)
#define PCL816_STATUS_INTSRC_DMA                PCL816_STATUS_INTSRC_SLOT(3)
#define PCL816_STATUS_INTSRC_MASK               PCL816_STATUS_INTSRC_SLOT(3)
#define PCL816_STATUS_INTACT                    BIT(6)
#define PCL816_STATUS_DRDY                      BIT(7)

#define MAGIC_DMA_WORD 0x5a5a

static const struct comedi_lrange range_pcl816 = {
        8, {
                BIP_RANGE(10),
                BIP_RANGE(5),
                BIP_RANGE(2.5),
                BIP_RANGE(1.25),
                UNI_RANGE(10),
                UNI_RANGE(5),
                UNI_RANGE(2.5),
                UNI_RANGE(1.25)
        }
};

struct pcl816_board {
        const char *name;
        int ai_maxdata;
        int ai_chanlist;
};

static const struct pcl816_board boardtypes[] = {
        {
                .name           = "pcl816",
                .ai_maxdata     = 0xffff,
                .ai_chanlist    = 1024,
        }, {
                .name           = "pcl814b",
                .ai_maxdata     = 0x3fff,
                .ai_chanlist    = 1024,
        },
};

struct pcl816_private {
        struct comedi_isadma *dma;
        unsigned int ai_poll_ptr;       /*  how many sampes transfer poll */
        unsigned int ai_cmd_running:1;
        unsigned int ai_cmd_canceled:1;
};

static void pcl816_ai_setup_dma(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                unsigned int unread_samples)
{
        struct pcl816_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];
        unsigned int max_samples = comedi_bytes_to_samples(s, desc->maxsize);
        unsigned int nsamples;

        comedi_isadma_disable(dma->chan);

        /*
         * Determine dma size based on the buffer maxsize plus the number of
         * unread samples and the number of samples remaining in the command.
         */
        nsamples = comedi_nsamples_left(s, max_samples + unread_samples);
        if (nsamples > unread_samples) {
                nsamples -= unread_samples;
                desc->size = comedi_samples_to_bytes(s, nsamples);
                comedi_isadma_program(desc);
        }
}

static void pcl816_ai_set_chan_range(struct comedi_device *dev,
                                     unsigned int chan,
                                     unsigned int range)
{
        outb(chan, dev->iobase + PCL816_MUX_REG);
        outb(range, dev->iobase + PCL816_RANGE_REG);
}

static void pcl816_ai_set_chan_scan(struct comedi_device *dev,
                                    unsigned int first_chan,
                                    unsigned int last_chan)
{
        outb(PCL816_MUX_SCAN(first_chan, last_chan),
             dev->iobase + PCL816_MUX_REG);
}

static void pcl816_ai_setup_chanlist(struct comedi_device *dev,
                                     unsigned int *chanlist,
                                     unsigned int seglen)
{
        unsigned int first_chan = CR_CHAN(chanlist[0]);
        unsigned int last_chan;
        unsigned int range;
        unsigned int i;

        /* store range list to card */
        for (i = 0; i < seglen; i++) {
                last_chan = CR_CHAN(chanlist[i]);
                range = CR_RANGE(chanlist[i]);

                pcl816_ai_set_chan_range(dev, last_chan, range);
        }

        udelay(1);

        pcl816_ai_set_chan_scan(dev, first_chan, last_chan);
}

static void pcl816_ai_clear_eoc(struct comedi_device *dev)
{
        /* writing any value clears the interrupt request */
        outb(0, dev->iobase + PCL816_CLRINT_REG);
}

static void pcl816_ai_soft_trig(struct comedi_device *dev)
{
        /* writing any value triggers a software conversion */
        outb(0, dev->iobase + PCL816_AI_LSB_REG);
}

static unsigned int pcl816_ai_get_sample(struct comedi_device *dev,
                                         struct comedi_subdevice *s)
{
        unsigned int val;

        val = inb(dev->iobase + PCL816_AI_MSB_REG) << 8;
        val |= inb(dev->iobase + PCL816_AI_LSB_REG);

        return val & s->maxdata;
}

static int pcl816_ai_eoc(struct comedi_device *dev,
                         struct comedi_subdevice *s,
                         struct comedi_insn *insn,
                         unsigned long context)
{
        unsigned int status;

        status = inb(dev->iobase + PCL816_STATUS_REG);
        if ((status & PCL816_STATUS_DRDY) == 0)
                return 0;
        return -EBUSY;
}

static bool pcl816_ai_next_chan(struct comedi_device *dev,
                                struct comedi_subdevice *s)
{
        struct comedi_cmd *cmd = &s->async->cmd;

        if (cmd->stop_src == TRIG_COUNT &&
            s->async->scans_done >= cmd->stop_arg) {
                s->async->events |= COMEDI_CB_EOA;
                return false;
        }

        return true;
}

static void transfer_from_dma_buf(struct comedi_device *dev,
                                  struct comedi_subdevice *s,
                                  unsigned short *ptr,
                                  unsigned int bufptr, unsigned int len)
{
        unsigned short val;
        int i;

        for (i = 0; i < len; i++) {
                val = ptr[bufptr++];
                comedi_buf_write_samples(s, &val, 1);

                if (!pcl816_ai_next_chan(dev, s))
                        return;
        }
}

static irqreturn_t pcl816_interrupt(int irq, void *d)
{
        struct comedi_device *dev = d;
        struct comedi_subdevice *s = dev->read_subdev;
        struct pcl816_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_isadma_desc *desc = &dma->desc[dma->cur_dma];
        unsigned int nsamples;
        unsigned int bufptr;

        if (!dev->attached || !devpriv->ai_cmd_running) {
                pcl816_ai_clear_eoc(dev);
                return IRQ_HANDLED;
        }

        if (devpriv->ai_cmd_canceled) {
                devpriv->ai_cmd_canceled = 0;
                pcl816_ai_clear_eoc(dev);
                return IRQ_HANDLED;
        }

        nsamples = comedi_bytes_to_samples(s, desc->size) -
                   devpriv->ai_poll_ptr;
        bufptr = devpriv->ai_poll_ptr;
        devpriv->ai_poll_ptr = 0;

        /* restart dma with the next buffer */
        dma->cur_dma = 1 - dma->cur_dma;
        pcl816_ai_setup_dma(dev, s, nsamples);

        transfer_from_dma_buf(dev, s, desc->virt_addr, bufptr, nsamples);

        pcl816_ai_clear_eoc(dev);

        comedi_handle_events(dev, s);
        return IRQ_HANDLED;
}

static int check_channel_list(struct comedi_device *dev,
                              struct comedi_subdevice *s,
                              unsigned int *chanlist,
                              unsigned int chanlen)
{
        unsigned int chansegment[16];
        unsigned int i, nowmustbechan, seglen;

        /*  correct channel and range number check itself comedi/range.c */
        if (chanlen < 1) {
                dev_err(dev->class_dev, "range/channel list is empty!\n");
                return 0;
        }

        if (chanlen > 1) {
                /*  first channel is every time ok */
                chansegment[0] = chanlist[0];
                for (i = 1, seglen = 1; i < chanlen; i++, seglen++) {
                        /*  we detect loop, this must by finish */
                        if (chanlist[0] == chanlist[i])
                                break;
                        nowmustbechan =
                            (CR_CHAN(chansegment[i - 1]) + 1) % chanlen;
                        if (nowmustbechan != CR_CHAN(chanlist[i])) {
                                /*  channel list isn't continuous :-( */
                                dev_dbg(dev->class_dev,
                                        "channel list must be continuous! chanlist[%i]=%d but must be %d or %d!\n",
                                        i, CR_CHAN(chanlist[i]), nowmustbechan,
                                        CR_CHAN(chanlist[0]));
                                return 0;
                        }
                        /*  well, this is next correct channel in list */
                        chansegment[i] = chanlist[i];
                }

                /*  check whole chanlist */
                for (i = 0; i < chanlen; i++) {
                        if (chanlist[i] != chansegment[i % seglen]) {
                                dev_dbg(dev->class_dev,
                                        "bad channel or range number! chanlist[%i]=%d,%d,%d and not %d,%d,%d!\n",
                                        i, CR_CHAN(chansegment[i]),
                                        CR_RANGE(chansegment[i]),
                                        CR_AREF(chansegment[i]),
                                        CR_CHAN(chanlist[i % seglen]),
                                        CR_RANGE(chanlist[i % seglen]),
                                        CR_AREF(chansegment[i % seglen]));
                                return 0;       /*  chan/gain list is strange */
                        }
                }
        } else {
                seglen = 1;
        }

        return seglen;  /*  we can serve this with MUX logic */
}

static int pcl816_ai_cmdtest(struct comedi_device *dev,
                             struct comedi_subdevice *s, struct comedi_cmd *cmd)
{
        int err = 0;

        /* Step 1 : check if triggers are trivially valid */

        err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW);
        err |= comedi_check_trigger_src(&cmd->scan_begin_src, TRIG_FOLLOW);
        err |= comedi_check_trigger_src(&cmd->convert_src,
                                        TRIG_EXT | TRIG_TIMER);
        err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
        err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);

        if (err)
                return 1;

        /* Step 2a : make sure trigger sources are unique */

        err |= comedi_check_trigger_is_unique(cmd->convert_src);
        err |= comedi_check_trigger_is_unique(cmd->stop_src);

        /* Step 2b : and mutually compatible */

        if (err)
                return 2;

        /* Step 3: check if arguments are trivially valid */

        err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);
        err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, 0);

        if (cmd->convert_src == TRIG_TIMER)
                err |= comedi_check_trigger_arg_min(&cmd->convert_arg, 10000);
        else    /* TRIG_EXT */
                err |= comedi_check_trigger_arg_is(&cmd->convert_arg, 0);

        err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
                                           cmd->chanlist_len);

        if (cmd->stop_src == TRIG_COUNT)
                err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1);
        else    /* TRIG_NONE */
                err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);

        if (err)
                return 3;

        /* step 4: fix up any arguments */
        if (cmd->convert_src == TRIG_TIMER) {
                unsigned int arg = cmd->convert_arg;

                comedi_8254_cascade_ns_to_timer(dev->pacer, &arg, cmd->flags);
                err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg);
        }

        if (err)
                return 4;

        /* step 5: complain about special chanlist considerations */

        if (cmd->chanlist) {
                if (!check_channel_list(dev, s, cmd->chanlist,
                                        cmd->chanlist_len))
                        return 5;       /*  incorrect channels list */
        }

        return 0;
}

static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
{
        struct pcl816_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int ctrl;
        unsigned int seglen;

        if (devpriv->ai_cmd_running)
                return -EBUSY;

        seglen = check_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len);
        if (seglen < 1)
                return -EINVAL;
        pcl816_ai_setup_chanlist(dev, cmd->chanlist, seglen);
        udelay(1);

        devpriv->ai_cmd_running = 1;
        devpriv->ai_poll_ptr = 0;
        devpriv->ai_cmd_canceled = 0;

        /* setup and enable dma for the first buffer */
        dma->cur_dma = 0;
        pcl816_ai_setup_dma(dev, s, 0);

        comedi_8254_set_mode(dev->pacer, 0, I8254_MODE1 | I8254_BINARY);
        comedi_8254_write(dev->pacer, 0, 0x0ff);
        udelay(1);
        comedi_8254_update_divisors(dev->pacer);
        comedi_8254_pacer_enable(dev->pacer, 1, 2, true);

        ctrl = PCL816_CTRL_INTEN | PCL816_CTRL_DMAEN |
               PCL816_CTRL_DMASRC_SLOT(0);
        if (cmd->convert_src == TRIG_TIMER)
                ctrl |= PCL816_CTRL_PACER_TRIG;
        else    /* TRIG_EXT */
                ctrl |= PCL816_CTRL_EXT_TRIG;

        outb(ctrl, dev->iobase + PCL816_CTRL_REG);
        outb((dma->chan << 4) | dev->irq,
             dev->iobase + PCL816_STATUS_REG);

        return 0;
}

static int pcl816_ai_poll(struct comedi_device *dev, struct comedi_subdevice *s)
{
        struct pcl816_private *devpriv = dev->private;
        struct comedi_isadma *dma = devpriv->dma;
        struct comedi_isadma_desc *desc;
        unsigned long flags;
        unsigned int poll;
        int ret;

        spin_lock_irqsave(&dev->spinlock, flags);

        poll = comedi_isadma_poll(dma);
        poll = comedi_bytes_to_samples(s, poll);
        if (poll > devpriv->ai_poll_ptr) {
                desc = &dma->desc[dma->cur_dma];
                transfer_from_dma_buf(dev, s, desc->virt_addr,
                                      devpriv->ai_poll_ptr,
                                      poll - devpriv->ai_poll_ptr);
                /* new buffer position */
                devpriv->ai_poll_ptr = poll;

                comedi_handle_events(dev, s);

                ret = comedi_buf_n_bytes_ready(s);
        } else {
                /* no new samples */
                ret = 0;
        }
        spin_unlock_irqrestore(&dev->spinlock, flags);

        return ret;
}

static int pcl816_ai_cancel(struct comedi_device *dev,
                            struct comedi_subdevice *s)
{
        struct pcl816_private *devpriv = dev->private;

        if (!devpriv->ai_cmd_running)
                return 0;

        outb(0, dev->iobase + PCL816_CTRL_REG);
        pcl816_ai_clear_eoc(dev);

        comedi_8254_pacer_enable(dev->pacer, 1, 2, false);

        devpriv->ai_cmd_running = 0;
        devpriv->ai_cmd_canceled = 1;

        return 0;
}

static int pcl816_ai_insn_read(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int range = CR_RANGE(insn->chanspec);
        int ret = 0;
        int i;

        outb(PCL816_CTRL_SOFT_TRIG, dev->iobase + PCL816_CTRL_REG);

        pcl816_ai_set_chan_range(dev, chan, range);
        pcl816_ai_set_chan_scan(dev, chan, chan);

        for (i = 0; i < insn->n; i++) {
                pcl816_ai_clear_eoc(dev);
                pcl816_ai_soft_trig(dev);

                ret = comedi_timeout(dev, s, insn, pcl816_ai_eoc, 0);
                if (ret)
                        break;

                data[i] = pcl816_ai_get_sample(dev, s);
        }
        outb(0, dev->iobase + PCL816_CTRL_REG);
        pcl816_ai_clear_eoc(dev);

        return ret ? ret : insn->n;
}

static int pcl816_di_insn_bits(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        data[1] = inb(dev->iobase + PCL816_DO_DI_LSB_REG) |
                  (inb(dev->iobase + PCL816_DO_DI_MSB_REG) << 8);

        return insn->n;
}

static int pcl816_do_insn_bits(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,
                               unsigned int *data)
{
        if (comedi_dio_update_state(s, data)) {
                outb(s->state & 0xff, dev->iobase + PCL816_DO_DI_LSB_REG);
                outb((s->state >> 8), dev->iobase + PCL816_DO_DI_MSB_REG);
        }

        data[1] = s->state;

        return insn->n;
}

static void pcl816_reset(struct comedi_device *dev)
{
        outb(0, dev->iobase + PCL816_CTRL_REG);
        pcl816_ai_set_chan_range(dev, 0, 0);
        pcl816_ai_clear_eoc(dev);

        /* set all digital outputs low */
        outb(0, dev->iobase + PCL816_DO_DI_LSB_REG);
        outb(0, dev->iobase + PCL816_DO_DI_MSB_REG);
}

static void pcl816_alloc_irq_and_dma(struct comedi_device *dev,
                                     struct comedi_devconfig *it)
{
        struct pcl816_private *devpriv = dev->private;
        unsigned int irq_num = it->options[1];
        unsigned int dma_chan = it->options[2];

        /* only IRQs 2-7 and DMA channels 3 and 1 are valid */
        if (!(irq_num >= 2 && irq_num <= 7) ||
            !(dma_chan == 3 || dma_chan == 1))
                return;

        if (request_irq(irq_num, pcl816_interrupt, 0, dev->board_name, dev))
                return;

        /* DMA uses two 16K buffers */
        devpriv->dma = comedi_isadma_alloc(dev, 2, dma_chan, dma_chan,
                                           PAGE_SIZE * 4, COMEDI_ISADMA_READ);
        if (!devpriv->dma)
                free_irq(irq_num, dev);
        else
                dev->irq = irq_num;
}

static void pcl816_free_dma(struct comedi_device *dev)
{
        struct pcl816_private *devpriv = dev->private;

        if (devpriv)
                comedi_isadma_free(devpriv->dma);
}

static int pcl816_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
        const struct pcl816_board *board = dev->board_ptr;
        struct pcl816_private *devpriv;
        struct comedi_subdevice *s;
        int ret;

        devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
        if (!devpriv)
                return -ENOMEM;

        ret = comedi_request_region(dev, it->options[0], 0x10);
        if (ret)
                return ret;

        /* an IRQ and DMA are required to support async commands */
        pcl816_alloc_irq_and_dma(dev, it);

        dev->pacer = comedi_8254_io_alloc(dev->iobase + PCL816_TIMER_BASE,
                                          I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
        if (IS_ERR(dev->pacer))
                return PTR_ERR(dev->pacer);

        ret = comedi_alloc_subdevices(dev, 4);
        if (ret)
                return ret;

        s = &dev->subdevices[0];
        s->type         = COMEDI_SUBD_AI;
        s->subdev_flags = SDF_CMD_READ | SDF_DIFF;
        s->n_chan       = 16;
        s->maxdata      = board->ai_maxdata;
        s->range_table  = &range_pcl816;
        s->insn_read    = pcl816_ai_insn_read;
        if (dev->irq) {
                dev->read_subdev = s;
                s->subdev_flags |= SDF_CMD_READ;
                s->len_chanlist = board->ai_chanlist;
                s->do_cmdtest   = pcl816_ai_cmdtest;
                s->do_cmd       = pcl816_ai_cmd;
                s->poll         = pcl816_ai_poll;
                s->cancel       = pcl816_ai_cancel;
        }

        /* Piggyback Slot1 subdevice */
        s = &dev->subdevices[1];
        s->type         = COMEDI_SUBD_UNUSED;

        /* Digital Input subdevice */
        s = &dev->subdevices[2];
        s->type         = COMEDI_SUBD_DI;
        s->subdev_flags = SDF_READABLE;
        s->n_chan       = 16;
        s->maxdata      = 1;
        s->range_table  = &range_digital;
        s->insn_bits    = pcl816_di_insn_bits;

        /* Digital Output subdevice */
        s = &dev->subdevices[3];
        s->type         = COMEDI_SUBD_DO;
        s->subdev_flags = SDF_WRITABLE;
        s->n_chan       = 16;
        s->maxdata      = 1;
        s->range_table  = &range_digital;
        s->insn_bits    = pcl816_do_insn_bits;

        pcl816_reset(dev);

        return 0;
}

static void pcl816_detach(struct comedi_device *dev)
{
        if (dev->private) {
                pcl816_ai_cancel(dev, dev->read_subdev);
                pcl816_reset(dev);
        }
        pcl816_free_dma(dev);
        comedi_legacy_detach(dev);
}

static struct comedi_driver pcl816_driver = {
        .driver_name    = "pcl816",
        .module         = THIS_MODULE,
        .attach         = pcl816_attach,
        .detach         = pcl816_detach,
        .board_name     = &boardtypes[0].name,
        .num_names      = ARRAY_SIZE(boardtypes),
        .offset         = sizeof(struct pcl816_board),
};
module_comedi_driver(pcl816_driver);

MODULE_AUTHOR("Comedi https://www.comedi.org");
MODULE_DESCRIPTION("Comedi low-level driver");
MODULE_LICENSE("GPL");