ems_pci.c

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/*
 * Copyright (C) 2007 Wolfgang Grandegger <[email protected]>
 * Copyright (C) 2008 Markus Plessing <[email protected]>
 * Copyright (C) 2008 Sebastian Haas <[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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/can/dev.h>
#include <linux/io.h>

#include "sja1000.h"

#define DRV_NAME  "ems_pci"

MODULE_AUTHOR("Sebastian Haas <[email protected]>");
MODULE_DESCRIPTION("Socket-CAN driver for EMS CPC-PCI/PCIe/104P CAN cards");
MODULE_SUPPORTED_DEVICE("EMS CPC-PCI/PCIe/104P CAN card");
MODULE_LICENSE("GPL v2");

#define EMS_PCI_V1_MAX_CHAN 2
#define EMS_PCI_V2_MAX_CHAN 4
#define EMS_PCI_MAX_CHAN    EMS_PCI_V2_MAX_CHAN

struct ems_pci_card {
    int version;
    int channels;

    struct pci_dev *pci_dev;
    struct net_device *net_dev[EMS_PCI_MAX_CHAN];

    void __iomem *conf_addr;
    void __iomem *base_addr;
};

#define EMS_PCI_CAN_CLOCK (16000000 / 2)

/*
 * Register definitions and descriptions are from LinCAN 0.3.3.
 *
 * PSB4610 PITA-2 bridge control registers
 */
#define PITA2_ICR           0x00    /* Interrupt Control Register */
#define PITA2_ICR_INT0      0x00000002  /* [RC] INT0 Active/Clear */
#define PITA2_ICR_INT0_EN   0x00020000  /* [RW] Enable INT0 */

#define PITA2_MISC          0x1c    /* Miscellaneous Register */
#define PITA2_MISC_CONFIG   0x04000000  /* Multiplexed parallel interface */

/*
 * Register definitions for the PLX 9030
 */
#define PLX_ICSR            0x4c   /* Interrupt Control/Status register */
#define PLX_ICSR_LINTI1_ENA 0x0001 /* LINTi1 Enable */
#define PLX_ICSR_PCIINT_ENA 0x0040 /* PCI Interrupt Enable */
#define PLX_ICSR_LINTI1_CLR 0x0400 /* Local Edge Triggerable Interrupt Clear */
#define PLX_ICSR_ENA_CLR    (PLX_ICSR_LINTI1_ENA | PLX_ICSR_PCIINT_ENA | \
                 PLX_ICSR_LINTI1_CLR)

/*
 * 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_PCI_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_PCI_CDR             (CDR_CBP | CDR_CLKOUT_MASK)

#define EMS_PCI_V1_BASE_BAR     1
#define EMS_PCI_V1_CONF_SIZE    4096 /* size of PITA control area */
#define EMS_PCI_V2_BASE_BAR     2
#define EMS_PCI_V2_CONF_SIZE    128 /* size of PLX control area */
#define EMS_PCI_CAN_BASE_OFFSET 0x400 /* offset where the controllers starts */
#define EMS_PCI_CAN_CTRL_SIZE   0x200 /* memory size for each controller */

#define EMS_PCI_BASE_SIZE  4096 /* size of controller area */

static DEFINE_PCI_DEVICE_TABLE(ems_pci_tbl) = {
    /* CPC-PCI v1 */
    {PCI_VENDOR_ID_SIEMENS, 0x2104, PCI_ANY_ID, PCI_ANY_ID,},
    /* CPC-PCI v2 */
    {PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9030, PCI_VENDOR_ID_PLX, 0x4000},
    /* CPC-104P v2 */
    {PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9030, PCI_VENDOR_ID_PLX, 0x4002},
    {0,}
};
MODULE_DEVICE_TABLE(pci, ems_pci_tbl);

/*
 * Helper to read internal registers from card logic (not CAN)
 */
static u8 ems_pci_v1_readb(struct ems_pci_card *card, unsigned int port)
{
    return readb(card->base_addr + (port * 4));
}

static u8 ems_pci_v1_read_reg(const struct sja1000_priv *priv, int port)
{
    return readb(priv->reg_base + (port * 4));
}

static void ems_pci_v1_write_reg(const struct sja1000_priv *priv,
                 int port, u8 val)
{
    writeb(val, priv->reg_base + (port * 4));
}

static void ems_pci_v1_post_irq(const struct sja1000_priv *priv)
{
    struct ems_pci_card *card = (struct ems_pci_card *)priv->priv;

    /* reset int flag of pita */
    writel(PITA2_ICR_INT0_EN | PITA2_ICR_INT0,
           card->conf_addr + PITA2_ICR);
}

static u8 ems_pci_v2_read_reg(const struct sja1000_priv *priv, int port)
{
    return readb(priv->reg_base + port);
}

static void ems_pci_v2_write_reg(const struct sja1000_priv *priv,
                 int port, u8 val)
{
    writeb(val, priv->reg_base + port);
}

static void ems_pci_v2_post_irq(const struct sja1000_priv *priv)
{
    struct ems_pci_card *card = (struct ems_pci_card *)priv->priv;

    writel(PLX_ICSR_ENA_CLR, card->conf_addr + PLX_ICSR);
}

/*
 * Check if a CAN controller is present at the specified location
 * by trying to set 'em into the PeliCAN mode
 */
static inline int ems_pci_check_chan(const struct sja1000_priv *priv)
{
    unsigned char res;

    /* Make sure SJA1000 is in reset mode */
    priv->write_reg(priv, REG_MOD, 1);

    priv->write_reg(priv, REG_CDR, CDR_PELICAN);

    /* read reset-values */
    res = priv->read_reg(priv, REG_CDR);

    if (res == CDR_PELICAN)
        return 1;

    return 0;
}

static void ems_pci_del_card(struct pci_dev *pdev)
{
    struct ems_pci_card *card = pci_get_drvdata(pdev);
    struct net_device *dev;
    int i = 0;

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

        if (!dev)
            continue;

        dev_info(&pdev->dev, "Removing %s.\n", dev->name);
        unregister_sja1000dev(dev);
        free_sja1000dev(dev);
    }

    if (card->base_addr != NULL)
        pci_iounmap(card->pci_dev, card->base_addr);

    if (card->conf_addr != NULL)
        pci_iounmap(card->pci_dev, card->conf_addr);

    kfree(card);

    pci_disable_device(pdev);
    pci_set_drvdata(pdev, NULL);
}

static void ems_pci_card_reset(struct ems_pci_card *card)
{
    /* Request board reset */
    writeb(0, card->base_addr);
}

/*
 * Probe PCI device for EMS CAN signature and register each available
 * CAN channel to SJA1000 Socket-CAN subsystem.
 */
static int __devinit ems_pci_add_card(struct pci_dev *pdev,
                    const struct pci_device_id *ent)
{
    struct sja1000_priv *priv;
    struct net_device *dev;
    struct ems_pci_card *card;
    int max_chan, conf_size, base_bar;
    int err, i;

    /* Enabling PCI device */
    if (pci_enable_device(pdev) < 0) {
        dev_err(&pdev->dev, "Enabling PCI device failed\n");
        return -ENODEV;
    }

    /* Allocating card structures to hold addresses, ... */
    card = kzalloc(sizeof(struct ems_pci_card), GFP_KERNEL);
    if (card == NULL) {
        dev_err(&pdev->dev, "Unable to allocate memory\n");
        pci_disable_device(pdev);
        return -ENOMEM;
    }

    pci_set_drvdata(pdev, card);

    card->pci_dev = pdev;

    card->channels = 0;

    if (pdev->vendor == PCI_VENDOR_ID_PLX) {
        card->version = 2; /* CPC-PCI v2 */
        max_chan = EMS_PCI_V2_MAX_CHAN;
        base_bar = EMS_PCI_V2_BASE_BAR;
        conf_size = EMS_PCI_V2_CONF_SIZE;
    } else {
        card->version = 1; /* CPC-PCI v1 */
        max_chan = EMS_PCI_V1_MAX_CHAN;
        base_bar = EMS_PCI_V1_BASE_BAR;
        conf_size = EMS_PCI_V1_CONF_SIZE;
    }

    /* Remap configuration space and controller memory area */
    card->conf_addr = pci_iomap(pdev, 0, conf_size);
    if (card->conf_addr == NULL) {
        err = -ENOMEM;
        goto failure_cleanup;
    }

    card->base_addr = pci_iomap(pdev, base_bar, EMS_PCI_BASE_SIZE);
    if (card->base_addr == NULL) {
        err = -ENOMEM;
        goto failure_cleanup;
    }

    if (card->version == 1) {
        /* Configure PITA-2 parallel interface (enable MUX) */
        writel(PITA2_MISC_CONFIG, card->conf_addr + PITA2_MISC);

        /* Check for unique EMS CAN signature */
        if (ems_pci_v1_readb(card, 0) != 0x55 ||
            ems_pci_v1_readb(card, 1) != 0xAA ||
            ems_pci_v1_readb(card, 2) != 0x01 ||
            ems_pci_v1_readb(card, 3) != 0xCB ||
            ems_pci_v1_readb(card, 4) != 0x11) {
            dev_err(&pdev->dev,
                "Not EMS Dr. Thomas Wuensche interface\n");
            err = -ENODEV;
            goto failure_cleanup;
        }
    }

    ems_pci_card_reset(card);

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

        card->net_dev[i] = dev;
        priv = netdev_priv(dev);
        priv->priv = card;
        priv->irq_flags = IRQF_SHARED;

        dev->irq = pdev->irq;
        priv->reg_base = card->base_addr + EMS_PCI_CAN_BASE_OFFSET
                    + (i * EMS_PCI_CAN_CTRL_SIZE);
        if (card->version == 1) {
            priv->read_reg  = ems_pci_v1_read_reg;
            priv->write_reg = ems_pci_v1_write_reg;
            priv->post_irq  = ems_pci_v1_post_irq;
        } else {
            priv->read_reg  = ems_pci_v2_read_reg;
            priv->write_reg = ems_pci_v2_write_reg;
            priv->post_irq  = ems_pci_v2_post_irq;
        }

        /* Check if channel is present */
        if (ems_pci_check_chan(priv)) {
            priv->can.clock.freq = EMS_PCI_CAN_CLOCK;
            priv->ocr = EMS_PCI_OCR;
            priv->cdr = EMS_PCI_CDR;

            SET_NETDEV_DEV(dev, &pdev->dev);

            if (card->version == 1)
                /* reset int flag of pita */
                writel(PITA2_ICR_INT0_EN | PITA2_ICR_INT0,
                       card->conf_addr + PITA2_ICR);
            else
                /* enable IRQ in PLX 9030 */
                writel(PLX_ICSR_ENA_CLR,
                       card->conf_addr + PLX_ICSR);

            /* Register SJA1000 device */
            err = register_sja1000dev(dev);
            if (err) {
                dev_err(&pdev->dev, "Registering device failed "
                            "(err=%d)\n", err);
                free_sja1000dev(dev);
                goto failure_cleanup;
            }

            card->channels++;

            dev_info(&pdev->dev, "Channel #%d at 0x%p, irq %d\n",
                    i + 1, priv->reg_base, dev->irq);
        } else {
            free_sja1000dev(dev);
        }
    }

    return 0;

failure_cleanup:
    dev_err(&pdev->dev, "Error: %d. Cleaning Up.\n", err);

    ems_pci_del_card(pdev);

    return err;
}

static struct pci_driver ems_pci_driver = {
    .name = DRV_NAME,
    .id_table = ems_pci_tbl,
    .probe = ems_pci_add_card,
    .remove = ems_pci_del_card,
};

module_pci_driver(ems_pci_driver);