ems_pcmcia.c

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/*
 * Copyright (C) 2008 Sebastian Haas (initial chardev implementation)
 * Copyright (C) 2010 Markus Plessing <[email protected]>
 * Rework for mainline by Oliver Hartkopp <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the version 2 of the GNU General Public License
 * as published by the Free Software Foundation
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <pcmcia/cistpl.h>
#include <pcmcia/ds.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include "sja1000.h"

#define DRV_NAME "ems_pcmcia"

MODULE_AUTHOR("Markus Plessing <[email protected]>");
MODULE_DESCRIPTION("Socket-CAN driver for EMS CPC-CARD cards");
MODULE_SUPPORTED_DEVICE("EMS CPC-CARD CAN card");
MODULE_LICENSE("GPL v2");

#define EMS_PCMCIA_MAX_CHAN 2

struct ems_pcmcia_card {
    int channels;
    struct pcmcia_device *pcmcia_dev;
    struct net_device *net_dev[EMS_PCMCIA_MAX_CHAN];
    void __iomem *base_addr;
};

#define EMS_PCMCIA_CAN_CLOCK (16000000 / 2)

/*
 * The board configuration is probably following:
 * RX1 is connected to ground.
 * TX1 is not connected.
 * CLKO is not connected.
 * Setting the OCR register to 0xDA is a good idea.
 * This means  normal output mode , push-pull and the correct polarity.
 */
#define EMS_PCMCIA_OCR (OCR_TX0_PUSHPULL | OCR_TX1_PUSHPULL)

/*
 * In the CDR register, you should set CBP to 1.
 * You will probably also want to set the clock divider value to 7
 * (meaning direct oscillator output) because the second SJA1000 chip
 * is driven by the first one CLKOUT output.
 */
#define EMS_PCMCIA_CDR (CDR_CBP | CDR_CLKOUT_MASK)
#define EMS_PCMCIA_MEM_SIZE 4096 /* Size of the remapped io-memory */
#define EMS_PCMCIA_CAN_BASE_OFFSET 0x100 /* Offset where controllers starts */
#define EMS_PCMCIA_CAN_CTRL_SIZE 0x80 /* Memory size for each controller */

#define EMS_CMD_RESET 0x00 /* Perform a reset of the card */
#define EMS_CMD_MAP   0x03 /* Map CAN controllers into card' memory */
#define EMS_CMD_UMAP  0x02 /* Unmap CAN controllers from card' memory */

static struct pcmcia_device_id ems_pcmcia_tbl[] = {
    PCMCIA_DEVICE_PROD_ID123("EMS_T_W", "CPC-Card", "V2.0", 0xeab1ea23,
                 0xa338573f, 0xe4575800),
    PCMCIA_DEVICE_NULL,
};

MODULE_DEVICE_TABLE(pcmcia, ems_pcmcia_tbl);

static u8 ems_pcmcia_read_reg(const struct sja1000_priv *priv, int port)
{
    return readb(priv->reg_base + port);
}

static void ems_pcmcia_write_reg(const struct sja1000_priv *priv, int port,
                 u8 val)
{
    writeb(val, priv->reg_base + port);
}

static irqreturn_t ems_pcmcia_interrupt(int irq, void *dev_id)
{
    struct ems_pcmcia_card *card = dev_id;
    struct net_device *dev;
    irqreturn_t retval = IRQ_NONE;
    int i, again;

    /* Card not present */
    if (readw(card->base_addr) != 0xAA55)
        return IRQ_HANDLED;

    do {
        again = 0;

        /* Check interrupt for each channel */
        for (i = 0; i < card->channels; i++) {
            dev = card->net_dev[i];
            if (!dev)
                continue;

            if (sja1000_interrupt(irq, dev) == IRQ_HANDLED)
                again = 1;
        }
        /* At least one channel handled the interrupt */
        if (again)
            retval = IRQ_HANDLED;

    } while (again);

    return retval;
}

/*
 * Check if a CAN controller is present at the specified location
 * by trying to set 'em into the PeliCAN mode
 */
static inline int ems_pcmcia_check_chan(struct sja1000_priv *priv)
{
    /* Make sure SJA1000 is in reset mode */
    ems_pcmcia_write_reg(priv, REG_MOD, 1);
    ems_pcmcia_write_reg(priv, REG_CDR, CDR_PELICAN);

    /* read reset-values */
    if (ems_pcmcia_read_reg(priv, REG_CDR) == CDR_PELICAN)
        return 1;

    return 0;
}

static void ems_pcmcia_del_card(struct pcmcia_device *pdev)
{
    struct ems_pcmcia_card *card = pdev->priv;
    struct net_device *dev;
    int i;

    free_irq(pdev->irq, card);

    for (i = 0; i < card->channels; i++) {
        dev = card->net_dev[i];
        if (!dev)
            continue;

        printk(KERN_INFO "%s: removing %s on channel #%d\n",
               DRV_NAME, dev->name, i);
        unregister_sja1000dev(dev);
        free_sja1000dev(dev);
    }

    writeb(EMS_CMD_UMAP, card->base_addr);
    iounmap(card->base_addr);
    kfree(card);

    pdev->priv = NULL;
}

/*
 * Probe PCI device for EMS CAN signature and register each available
 * CAN channel to SJA1000 Socket-CAN subsystem.
 */
static int __devinit ems_pcmcia_add_card(struct pcmcia_device *pdev,
                     unsigned long base)
{
    struct sja1000_priv *priv;
    struct net_device *dev;
    struct ems_pcmcia_card *card;
    int err, i;

    /* Allocating card structures to hold addresses, ... */
    card = kzalloc(sizeof(struct ems_pcmcia_card), GFP_KERNEL);
    if (!card)
        return -ENOMEM;

    pdev->priv = card;
    card->channels = 0;

    card->base_addr = ioremap(base, EMS_PCMCIA_MEM_SIZE);
    if (!card->base_addr) {
        err = -ENOMEM;
        goto failure_cleanup;
    }

    /* Check for unique EMS CAN signature */
    if (readw(card->base_addr) != 0xAA55) {
        err = -ENODEV;
        goto failure_cleanup;
    }

    /* Request board reset */
    writeb(EMS_CMD_RESET, card->base_addr);

    /* Make sure CAN controllers are mapped into card's memory space */
    writeb(EMS_CMD_MAP, card->base_addr);

    /* Detect available channels */
    for (i = 0; i < EMS_PCMCIA_MAX_CHAN; i++) {
        dev = alloc_sja1000dev(0);
        if (!dev) {
            err = -ENOMEM;
            goto failure_cleanup;
        }

        card->net_dev[i] = dev;
        priv = netdev_priv(dev);
        priv->priv = card;
        SET_NETDEV_DEV(dev, &pdev->dev);

        priv->irq_flags = IRQF_SHARED;
        dev->irq = pdev->irq;
        priv->reg_base = card->base_addr + EMS_PCMCIA_CAN_BASE_OFFSET +
            (i * EMS_PCMCIA_CAN_CTRL_SIZE);

        /* Check if channel is present */
        if (ems_pcmcia_check_chan(priv)) {
            priv->read_reg  = ems_pcmcia_read_reg;
            priv->write_reg = ems_pcmcia_write_reg;
            priv->can.clock.freq = EMS_PCMCIA_CAN_CLOCK;
            priv->ocr = EMS_PCMCIA_OCR;
            priv->cdr = EMS_PCMCIA_CDR;
            priv->flags |= SJA1000_CUSTOM_IRQ_HANDLER;

            /* Register SJA1000 device */
            err = register_sja1000dev(dev);
            if (err) {
                free_sja1000dev(dev);
                goto failure_cleanup;
            }

            card->channels++;

            printk(KERN_INFO "%s: registered %s on channel "
                   "#%d at 0x%p, irq %d\n", DRV_NAME, dev->name,
                   i, priv->reg_base, dev->irq);
        } else
            free_sja1000dev(dev);
    }

    err = request_irq(dev->irq, &ems_pcmcia_interrupt, IRQF_SHARED,
              DRV_NAME, card);
    if (!err)
        return 0;

failure_cleanup:
    ems_pcmcia_del_card(pdev);
    return err;
}

/*
 * Setup PCMCIA socket and probe for EMS CPC-CARD
 */
static int __devinit ems_pcmcia_probe(struct pcmcia_device *dev)
{
    int csval;

    /* General socket configuration */
    dev->config_flags |= CONF_ENABLE_IRQ;
    dev->config_index = 1;
    dev->config_regs = PRESENT_OPTION;

    /* The io structure describes IO port mapping */
    dev->resource[0]->end = 16;
    dev->resource[0]->flags |= IO_DATA_PATH_WIDTH_8;
    dev->resource[1]->end = 16;
    dev->resource[1]->flags |= IO_DATA_PATH_WIDTH_16;
    dev->io_lines = 5;

    /* Allocate a memory window */
    dev->resource[2]->flags =
        (WIN_DATA_WIDTH_8 | WIN_MEMORY_TYPE_CM | WIN_ENABLE);
    dev->resource[2]->start = dev->resource[2]->end = 0;

    csval = pcmcia_request_window(dev, dev->resource[2], 0);
    if (csval) {
        dev_err(&dev->dev, "pcmcia_request_window failed (err=%d)\n",
            csval);
        return 0;
    }

    csval = pcmcia_map_mem_page(dev, dev->resource[2], dev->config_base);
    if (csval) {
        dev_err(&dev->dev, "pcmcia_map_mem_page failed (err=%d)\n",
            csval);
        return 0;
    }

    csval = pcmcia_enable_device(dev);
    if (csval) {
        dev_err(&dev->dev, "pcmcia_enable_device failed (err=%d)\n",
            csval);
        return 0;
    }

    ems_pcmcia_add_card(dev, dev->resource[2]->start);
    return 0;
}

/*
 * Release claimed resources
 */
static void ems_pcmcia_remove(struct pcmcia_device *dev)
{
    ems_pcmcia_del_card(dev);
    pcmcia_disable_device(dev);
}

static struct pcmcia_driver ems_pcmcia_driver = {
    .name = DRV_NAME,
    .probe = ems_pcmcia_probe,
    .remove = ems_pcmcia_remove,
    .id_table = ems_pcmcia_tbl,
};

static int __init ems_pcmcia_init(void)
{
    return pcmcia_register_driver(&ems_pcmcia_driver);
}
module_init(ems_pcmcia_init);

static void __exit ems_pcmcia_exit(void)
{
    pcmcia_unregister_driver(&ems_pcmcia_driver);
}
module_exit(ems_pcmcia_exit);