// SPDX-License-Identifier: GPL-2.0

/***************************************************************************
 *    copyright            : (C) 2001, 2002 by Frank Mori Hess
 ***************************************************************************/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#define dev_fmt pr_fmt

#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <asm/dma.h>
#include <linux/dma-mapping.h>
#include <linux/string.h>
#include <linux/init.h>
#include "nec7210.h"
#include "gpibP.h"

// struct which defines private_data for pc2 driver
struct pc2_priv {
        struct nec7210_priv nec7210_priv;
        unsigned int irq;
        // io address that clears interrupt for pc2a (0x2f0 + irq)
        unsigned int clear_intr_addr;
};

// pc2 uses 8 consecutive io addresses
static const int pc2_iosize = 8;
static const int pc2a_iosize = 8;
static const int pc2_2a_iosize = 16;

// offset between io addresses of successive nec7210 registers
static const int pc2a_reg_offset = 0x400;
static const int pc2_reg_offset = 1;

// interrupt service routine
static irqreturn_t pc2_interrupt(int irq, void *arg);
static irqreturn_t pc2a_interrupt(int irq, void *arg);

// pc2 specific registers and bits

// interrupt clear register address
static const int pc2a_clear_intr_iobase = 0x2f0;
static inline unsigned int CLEAR_INTR_REG(unsigned int irq)
{
        return pc2a_clear_intr_iobase + irq;
}

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("GPIB driver for PC2/PC2a and compatible devices");

/*
 * GPIB interrupt service routines
 */

irqreturn_t pc2_interrupt(int irq, void *arg)
{
        struct gpib_board *board = arg;
        struct pc2_priv *priv = board->private_data;
        unsigned long flags;
        irqreturn_t retval;

        spin_lock_irqsave(&board->spinlock, flags);
        retval = nec7210_interrupt(board, &priv->nec7210_priv);
        spin_unlock_irqrestore(&board->spinlock, flags);
        return retval;
}

irqreturn_t pc2a_interrupt(int irq, void *arg)
{
        struct gpib_board *board = arg;
        struct pc2_priv *priv = board->private_data;
        int status1, status2;
        unsigned long flags;
        irqreturn_t retval;

        spin_lock_irqsave(&board->spinlock, flags);
        // read interrupt status (also clears status)
        status1 = read_byte(&priv->nec7210_priv, ISR1);
        status2 = read_byte(&priv->nec7210_priv, ISR2);
        /* clear interrupt circuit */
        if (priv->irq)
                outb(0xff, CLEAR_INTR_REG(priv->irq));
        retval = nec7210_interrupt_have_status(board, &priv->nec7210_priv, status1, status2);
        spin_unlock_irqrestore(&board->spinlock, flags);
        return retval;
}

// wrappers for interface functions
static int pc2_read(struct gpib_board *board, u8 *buffer, size_t length, int *end,
                    size_t *bytes_read)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_read(board, &priv->nec7210_priv, buffer, length, end, bytes_read);
}

static int pc2_write(struct gpib_board *board, u8 *buffer, size_t length, int send_eoi,
                     size_t *bytes_written)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_write(board, &priv->nec7210_priv, buffer, length, send_eoi, bytes_written);
}

static int pc2_command(struct gpib_board *board, u8 *buffer,
                       size_t length, size_t *bytes_written)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_command(board, &priv->nec7210_priv, buffer, length, bytes_written);
}

static int pc2_take_control(struct gpib_board *board, int synchronous)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_take_control(board, &priv->nec7210_priv, synchronous);
}

static int pc2_go_to_standby(struct gpib_board *board)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_go_to_standby(board, &priv->nec7210_priv);
}

static int pc2_request_system_control(struct gpib_board *board, int request_control)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_request_system_control(board, &priv->nec7210_priv, request_control);
}

static void pc2_interface_clear(struct gpib_board *board, int assert)
{
        struct pc2_priv *priv = board->private_data;

        nec7210_interface_clear(board, &priv->nec7210_priv, assert);
}

static void pc2_remote_enable(struct gpib_board *board, int enable)
{
        struct pc2_priv *priv = board->private_data;

        nec7210_remote_enable(board, &priv->nec7210_priv, enable);
}

static int pc2_enable_eos(struct gpib_board *board, u8 eos_byte, int compare_8_bits)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_enable_eos(board, &priv->nec7210_priv, eos_byte, compare_8_bits);
}

static void pc2_disable_eos(struct gpib_board *board)
{
        struct pc2_priv *priv = board->private_data;

        nec7210_disable_eos(board, &priv->nec7210_priv);
}

static unsigned int pc2_update_status(struct gpib_board *board, unsigned int clear_mask)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_update_status(board, &priv->nec7210_priv, clear_mask);
}

static int pc2_primary_address(struct gpib_board *board, unsigned int address)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_primary_address(board, &priv->nec7210_priv, address);
}

static int pc2_secondary_address(struct gpib_board *board, unsigned int address, int enable)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_secondary_address(board, &priv->nec7210_priv, address, enable);
}

static int pc2_parallel_poll(struct gpib_board *board, u8 *result)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_parallel_poll(board, &priv->nec7210_priv, result);
}

static void pc2_parallel_poll_configure(struct gpib_board *board, u8 config)
{
        struct pc2_priv *priv = board->private_data;

        nec7210_parallel_poll_configure(board, &priv->nec7210_priv, config);
}

static void pc2_parallel_poll_response(struct gpib_board *board, int ist)
{
        struct pc2_priv *priv = board->private_data;

        nec7210_parallel_poll_response(board, &priv->nec7210_priv, ist);
}

static void pc2_serial_poll_response(struct gpib_board *board, u8 status)
{
        struct pc2_priv *priv = board->private_data;

        nec7210_serial_poll_response(board, &priv->nec7210_priv, status);
}

static u8 pc2_serial_poll_status(struct gpib_board *board)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_serial_poll_status(board, &priv->nec7210_priv);
}

static int pc2_t1_delay(struct gpib_board *board, unsigned int nano_sec)
{
        struct pc2_priv *priv = board->private_data;

        return nec7210_t1_delay(board, &priv->nec7210_priv, nano_sec);
}

static void pc2_return_to_local(struct gpib_board *board)
{
        struct pc2_priv *priv = board->private_data;

        nec7210_return_to_local(board, &priv->nec7210_priv);
}

static int allocate_private(struct gpib_board *board)
{
        struct pc2_priv *priv;

        board->private_data = kzalloc_obj(struct pc2_priv);
        if (!board->private_data)
                return -ENOMEM;
        priv = board->private_data;
        init_nec7210_private(&priv->nec7210_priv);
        return 0;
}

static void free_private(struct gpib_board *board)
{
        kfree(board->private_data);
        board->private_data = NULL;
}

static int pc2_generic_attach(struct gpib_board *board, const struct gpib_board_config *config,
                              enum nec7210_chipset chipset)
{
        struct pc2_priv *pc2_priv;
        struct nec7210_priv *nec_priv;
        int retval;

        board->status = 0;
        retval = allocate_private(board);
        if (retval)
                return retval;
        pc2_priv = board->private_data;
        nec_priv = &pc2_priv->nec7210_priv;
        nec_priv->read_byte = nec7210_ioport_read_byte;
        nec_priv->write_byte = nec7210_ioport_write_byte;
        nec_priv->type = chipset;

#ifndef PC2_DMA
        /*
         * board->dev hasn't been initialized, so forget about DMA until this driver
         * is adapted to use isa_register_driver.
         */
        if (config->ibdma)
        // driver needs to be adapted to use isa_register_driver to get a struct device*
                dev_err(board->gpib_dev, "DMA disabled for pc2 gpib");
#else
        if (config->ibdma) {
                nec_priv->dma_buffer_length = 0x1000;
                nec_priv->dma_buffer = dma_alloc_coherent(board->dev,
                                                          nec_priv->dma_buffer_length, &
                                                          nec_priv->dma_buffer_addr, GFP_ATOMIC);
                if (!nec_priv->dma_buffer)
                        return -ENOMEM;

                // request isa dma channel
                if (request_dma(config->ibdma, "pc2")) {
                        dev_err(board->gpib_dev, "can't request DMA %d\n", config->ibdma);
                        return -1;
                }
                nec_priv->dma_channel = config->ibdma;
        }
#endif

        return 0;
}

static int pc2_attach(struct gpib_board *board, const struct gpib_board_config *config)
{
        int isr_flags = 0;
        struct pc2_priv *pc2_priv;
        struct nec7210_priv *nec_priv;
        int retval;

        retval = pc2_generic_attach(board, config, NEC7210);
        if (retval)
                return retval;

        pc2_priv = board->private_data;
        nec_priv = &pc2_priv->nec7210_priv;
        nec_priv->offset = pc2_reg_offset;

        if (!request_region(config->ibbase, pc2_iosize, "pc2")) {
                dev_err(board->gpib_dev, "ioports are already in use\n");
                return -EBUSY;
        }
        nec_priv->iobase = config->ibbase;

        nec7210_board_reset(nec_priv, board);

        // install interrupt handler
        if (config->ibirq) {
                if (request_irq(config->ibirq, pc2_interrupt, isr_flags, "pc2", board)) {
                        dev_err(board->gpib_dev, "can't request IRQ %d\n", config->ibirq);
                        return -EBUSY;
                }
        }
        pc2_priv->irq = config->ibirq;
        /* poll so we can detect assertion of ATN */
        if (gpib_request_pseudo_irq(board, pc2_interrupt)) {
                dev_err(board->gpib_dev, "failed to allocate pseudo_irq\n");
                return -1;
        }
        /* set internal counter register for 8 MHz input clock */
        write_byte(nec_priv, ICR | 8, AUXMR);

        nec7210_board_online(nec_priv, board);

        return 0;
}

static void pc2_detach(struct gpib_board *board)
{
        struct pc2_priv *pc2_priv = board->private_data;
        struct nec7210_priv *nec_priv;

        if (pc2_priv) {
                nec_priv = &pc2_priv->nec7210_priv;
#ifdef PC2_DMA
                if (nec_priv->dma_channel)
                        free_dma(nec_priv->dma_channel);
#endif
                gpib_free_pseudo_irq(board);
                if (pc2_priv->irq)
                        free_irq(pc2_priv->irq, board);
                if (nec_priv->iobase) {
                        nec7210_board_reset(nec_priv, board);
                        release_region(nec_priv->iobase, pc2_iosize);
                }
                if (nec_priv->dma_buffer) {
                        dma_free_coherent(board->dev, nec_priv->dma_buffer_length,
                                          nec_priv->dma_buffer, nec_priv->dma_buffer_addr);
                        nec_priv->dma_buffer = NULL;
                }
        }
        free_private(board);
}

static int pc2a_common_attach(struct gpib_board *board, const struct gpib_board_config *config,
                              unsigned int num_registers, enum nec7210_chipset chipset)
{
        unsigned int i, j;
        struct pc2_priv *pc2_priv;
        struct nec7210_priv *nec_priv;
        int retval;

        retval = pc2_generic_attach(board, config, chipset);
        if (retval)
                return retval;

        pc2_priv = board->private_data;
        nec_priv = &pc2_priv->nec7210_priv;
        nec_priv->offset = pc2a_reg_offset;

        switch (config->ibbase) {
        case 0x02e1:
        case 0x22e1:
        case 0x42e1:
        case 0x62e1:
                break;
        default:
                dev_err(board->gpib_dev, "PCIIa base range invalid, must be one of 0x[0246]2e1, but is 0x%x\n",
                        config->ibbase);
                return -1;
        }

        if (config->ibirq) {
                if (config->ibirq < 2 || config->ibirq > 7) {
                        dev_err(board->gpib_dev, "illegal interrupt level %i\n",
                                config->ibirq);
                        return -1;
                }
        } else  {
                dev_err(board->gpib_dev, "interrupt disabled, using polling mode (slow)\n");
        }
#ifdef CHECK_IOPORTS
        unsigned int err = 0;

        for (i = 0; i < num_registers; i++) {
                if (check_region(config->ibbase + i * pc2a_reg_offset, 1))
                        err++;
        }
        if (config->ibirq && check_region(pc2a_clear_intr_iobase + config->ibirq, 1))
                err++;
        if (err) {
                dev_err(board->gpib_dev, "ioports are already in use");
                return -EBUSY;
        }
#endif
        for (i = 0; i < num_registers; i++) {
                if (!request_region(config->ibbase +
                                        i * pc2a_reg_offset, 1, "pc2a")) {
                        dev_err(board->gpib_dev, "ioports are already in use");
                        for (j = 0; j < i; j++)
                                release_region(config->ibbase +
                                        j * pc2a_reg_offset, 1);
                        return -EBUSY;
                }
        }
        nec_priv->iobase = config->ibbase;
        if (config->ibirq) {
                if (!request_region(pc2a_clear_intr_iobase + config->ibirq, 1, "pc2a"))  {
                        dev_err(board->gpib_dev, "ioports are already in use");
                        return -1;
                }
                pc2_priv->clear_intr_addr = pc2a_clear_intr_iobase + config->ibirq;
                if (request_irq(config->ibirq, pc2a_interrupt, 0, "pc2a", board)) {
                        dev_err(board->gpib_dev, "can't request IRQ %d\n", config->ibirq);
                        return -EBUSY;
                }
        }
        pc2_priv->irq = config->ibirq;
        /* poll so we can detect assertion of ATN */
        if (gpib_request_pseudo_irq(board, pc2_interrupt)) {
                dev_err(board->gpib_dev, "failed to allocate pseudo_irq\n");
                return -1;
        }

        // make sure interrupt is clear
        if (pc2_priv->irq)
                outb(0xff, CLEAR_INTR_REG(pc2_priv->irq));

        nec7210_board_reset(nec_priv, board);

        /* set internal counter register for 8 MHz input clock */
        write_byte(nec_priv, ICR | 8, AUXMR);

        nec7210_board_online(nec_priv, board);

        return 0;
}

static int pc2a_attach(struct gpib_board *board, const struct gpib_board_config *config)
{
        return pc2a_common_attach(board, config, pc2a_iosize, NEC7210);
}

static int pc2a_cb7210_attach(struct gpib_board *board, const struct gpib_board_config *config)
{
        return pc2a_common_attach(board, config, pc2a_iosize, CB7210);
}

static int pc2_2a_attach(struct gpib_board *board, const struct gpib_board_config *config)
{
        return pc2a_common_attach(board, config, pc2_2a_iosize, NAT4882);
}

static void pc2a_common_detach(struct gpib_board *board, unsigned int num_registers)
{
        int i;
        struct pc2_priv *pc2_priv = board->private_data;
        struct nec7210_priv *nec_priv;

        if (pc2_priv) {
                nec_priv = &pc2_priv->nec7210_priv;
#ifdef PC2_DMA
                if (nec_priv->dma_channel)
                        free_dma(nec_priv->dma_channel);
#endif
                gpib_free_pseudo_irq(board);
                if (pc2_priv->irq)
                        free_irq(pc2_priv->irq, board);
                if (nec_priv->iobase) {
                        nec7210_board_reset(nec_priv, board);
                        for (i = 0; i < num_registers; i++)
                                release_region(nec_priv->iobase +
                                               i * pc2a_reg_offset, 1);
                }
                if (pc2_priv->clear_intr_addr)
                        release_region(pc2_priv->clear_intr_addr, 1);
                if (nec_priv->dma_buffer) {
                        dma_free_coherent(board->dev, nec_priv->dma_buffer_length,
                                          nec_priv->dma_buffer,
                                          nec_priv->dma_buffer_addr);
                        nec_priv->dma_buffer = NULL;
                }
        }
        free_private(board);
}

static void pc2a_detach(struct gpib_board *board)
{
        pc2a_common_detach(board, pc2a_iosize);
}

static void pc2_2a_detach(struct gpib_board *board)
{
        pc2a_common_detach(board, pc2_2a_iosize);
}

static struct gpib_interface pc2_interface = {
        .name = "pcII",
        .attach =       pc2_attach,
        .detach =       pc2_detach,
        .read = pc2_read,
        .write =        pc2_write,
        .command =      pc2_command,
        .take_control = pc2_take_control,
        .go_to_standby =        pc2_go_to_standby,
        .request_system_control =       pc2_request_system_control,
        .interface_clear =      pc2_interface_clear,
        .remote_enable =        pc2_remote_enable,
        .enable_eos =   pc2_enable_eos,
        .disable_eos =  pc2_disable_eos,
        .parallel_poll =        pc2_parallel_poll,
        .parallel_poll_configure =      pc2_parallel_poll_configure,
        .parallel_poll_response =       pc2_parallel_poll_response,
        .local_parallel_poll_mode = NULL, // XXX
        .line_status =  NULL,
        .update_status =        pc2_update_status,
        .primary_address =      pc2_primary_address,
        .secondary_address =    pc2_secondary_address,
        .serial_poll_response = pc2_serial_poll_response,
        .serial_poll_status =   pc2_serial_poll_status,
        .t1_delay = pc2_t1_delay,
        .return_to_local = pc2_return_to_local,
};

static struct gpib_interface pc2a_interface = {
        .name = "pcIIa",
        .attach =       pc2a_attach,
        .detach =       pc2a_detach,
        .read = pc2_read,
        .write =        pc2_write,
        .command =      pc2_command,
        .take_control = pc2_take_control,
        .go_to_standby =        pc2_go_to_standby,
        .request_system_control =       pc2_request_system_control,
        .interface_clear =      pc2_interface_clear,
        .remote_enable =        pc2_remote_enable,
        .enable_eos =   pc2_enable_eos,
        .disable_eos =  pc2_disable_eos,
        .parallel_poll =        pc2_parallel_poll,
        .parallel_poll_configure =      pc2_parallel_poll_configure,
        .parallel_poll_response =       pc2_parallel_poll_response,
        .local_parallel_poll_mode = NULL, // XXX
        .line_status =  NULL,
        .update_status =        pc2_update_status,
        .primary_address =      pc2_primary_address,
        .secondary_address =    pc2_secondary_address,
        .serial_poll_response = pc2_serial_poll_response,
        .serial_poll_status =   pc2_serial_poll_status,
        .t1_delay = pc2_t1_delay,
        .return_to_local = pc2_return_to_local,
};

static struct gpib_interface pc2a_cb7210_interface = {
        .name = "pcIIa_cb7210",
        .attach =       pc2a_cb7210_attach,
        .detach =       pc2a_detach,
        .read = pc2_read,
        .write =        pc2_write,
        .command =      pc2_command,
        .take_control = pc2_take_control,
        .go_to_standby =        pc2_go_to_standby,
        .request_system_control =       pc2_request_system_control,
        .interface_clear =      pc2_interface_clear,
        .remote_enable =        pc2_remote_enable,
        .enable_eos =   pc2_enable_eos,
        .disable_eos =  pc2_disable_eos,
        .parallel_poll =        pc2_parallel_poll,
        .parallel_poll_configure =      pc2_parallel_poll_configure,
        .parallel_poll_response =       pc2_parallel_poll_response,
        .local_parallel_poll_mode = NULL, // XXX
        .line_status =  NULL, // XXX
        .update_status =        pc2_update_status,
        .primary_address =      pc2_primary_address,
        .secondary_address =    pc2_secondary_address,
        .serial_poll_response = pc2_serial_poll_response,
        .serial_poll_status =   pc2_serial_poll_status,
        .t1_delay = pc2_t1_delay,
        .return_to_local = pc2_return_to_local,
};

static struct gpib_interface pc2_2a_interface = {
        .name = "pcII_IIa",
        .attach =       pc2_2a_attach,
        .detach =       pc2_2a_detach,
        .read = pc2_read,
        .write =        pc2_write,
        .command =      pc2_command,
        .take_control = pc2_take_control,
        .go_to_standby =        pc2_go_to_standby,
        .request_system_control =       pc2_request_system_control,
        .interface_clear =      pc2_interface_clear,
        .remote_enable =        pc2_remote_enable,
        .enable_eos =   pc2_enable_eos,
        .disable_eos =  pc2_disable_eos,
        .parallel_poll =        pc2_parallel_poll,
        .parallel_poll_configure =      pc2_parallel_poll_configure,
        .parallel_poll_response =       pc2_parallel_poll_response,
        .local_parallel_poll_mode = NULL, // XXX
        .line_status =  NULL,
        .update_status =        pc2_update_status,
        .primary_address =      pc2_primary_address,
        .secondary_address =    pc2_secondary_address,
        .serial_poll_response = pc2_serial_poll_response,
        .serial_poll_status =   pc2_serial_poll_status,
        .t1_delay = pc2_t1_delay,
        .return_to_local = pc2_return_to_local,
};

static int __init pc2_init_module(void)
{
        int ret;

        ret = gpib_register_driver(&pc2_interface, THIS_MODULE);
        if (ret) {
                pr_err("gpib_register_driver failed: error = %d\n", ret);
                return ret;
        }

        ret = gpib_register_driver(&pc2a_interface, THIS_MODULE);
        if (ret) {
                pr_err("gpib_register_driver failed: error = %d\n", ret);
                goto err_pc2a;
        }

        ret = gpib_register_driver(&pc2a_cb7210_interface, THIS_MODULE);
        if (ret) {
                pr_err("gpib_register_driver failed: error = %d\n", ret);
                goto err_cb7210;
        }

        ret = gpib_register_driver(&pc2_2a_interface, THIS_MODULE);
        if (ret) {
                pr_err("gpib_register_driver failed: error = %d\n", ret);
                goto err_pc2_2a;
        }

        return 0;

err_pc2_2a:
        gpib_unregister_driver(&pc2a_cb7210_interface);
err_cb7210:
        gpib_unregister_driver(&pc2a_interface);
err_pc2a:
        gpib_unregister_driver(&pc2_interface);

        return ret;
}

static void __exit pc2_exit_module(void)
{
        gpib_unregister_driver(&pc2_interface);
        gpib_unregister_driver(&pc2a_interface);
        gpib_unregister_driver(&pc2a_cb7210_interface);
        gpib_unregister_driver(&pc2_2a_interface);
}

module_init(pc2_init_module);
module_exit(pc2_exit_module);