xilinx_ps2.c

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/*
 * Xilinx XPS PS/2 device driver
 *
 * (c) 2005 MontaVista Software, Inc.
 * (c) 2008 Xilinx, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * 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.,
 * 675 Mass Ave, Cambridge, MA 02139, USA.
 */


#include <linux/module.h>
#include <linux/serio.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>

#define DRIVER_NAME     "xilinx_ps2"

/* Register offsets for the xps2 device */
#define XPS2_SRST_OFFSET    0x00000000 /* Software Reset register */
#define XPS2_STATUS_OFFSET  0x00000004 /* Status register */
#define XPS2_RX_DATA_OFFSET 0x00000008 /* Receive Data register */
#define XPS2_TX_DATA_OFFSET 0x0000000C /* Transmit Data register */
#define XPS2_GIER_OFFSET    0x0000002C /* Global Interrupt Enable reg */
#define XPS2_IPISR_OFFSET   0x00000030 /* Interrupt Status register */
#define XPS2_IPIER_OFFSET   0x00000038 /* Interrupt Enable register */

/* Reset Register Bit Definitions */
#define XPS2_SRST_RESET     0x0000000A /* Software Reset  */

/* Status Register Bit Positions */
#define XPS2_STATUS_RX_FULL 0x00000001 /* Receive Full  */
#define XPS2_STATUS_TX_FULL 0x00000002 /* Transmit Full  */

/* Bit definitions for ISR/IER registers. Both the registers have the same bit
 * definitions and are only defined once. */
#define XPS2_IPIXR_WDT_TOUT 0x00000001 /* Watchdog Timeout Interrupt */
#define XPS2_IPIXR_TX_NOACK 0x00000002 /* Transmit No ACK Interrupt */
#define XPS2_IPIXR_TX_ACK   0x00000004 /* Transmit ACK (Data) Interrupt */
#define XPS2_IPIXR_RX_OVF   0x00000008 /* Receive Overflow Interrupt */
#define XPS2_IPIXR_RX_ERR   0x00000010 /* Receive Error Interrupt */
#define XPS2_IPIXR_RX_FULL  0x00000020 /* Receive Data Interrupt */

/* Mask for all the Transmit Interrupts */
#define XPS2_IPIXR_TX_ALL   (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)

/* Mask for all the Receive Interrupts */
#define XPS2_IPIXR_RX_ALL   (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
                 XPS2_IPIXR_RX_FULL)

/* Mask for all the Interrupts */
#define XPS2_IPIXR_ALL      (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
                 XPS2_IPIXR_WDT_TOUT)

/* Global Interrupt Enable mask */
#define XPS2_GIER_GIE_MASK  0x80000000

struct xps2data {
    int irq;
    spinlock_t lock;
    void __iomem *base_address; /* virt. address of control registers */
    unsigned int flags;
    struct serio *serio;        /* serio */
    struct device *dev;
};

/************************************/
/* XPS PS/2 data transmission calls */
/************************************/

static int xps2_recv(struct xps2data *drvdata, u8 *byte)
{
    u32 sr;
    int status = -1;

    /* If there is data available in the PS/2 receiver, read it */
    sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
    if (sr & XPS2_STATUS_RX_FULL) {
        *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
        status = 0;
    }

    return status;
}

/*********************/
/* Interrupt handler */
/*********************/
static irqreturn_t xps2_interrupt(int irq, void *dev_id)
{
    struct xps2data *drvdata = dev_id;
    u32 intr_sr;
    u8 c;
    int status;

    /* Get the PS/2 interrupts and clear them */
    intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
    out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);

    /* Check which interrupt is active */
    if (intr_sr & XPS2_IPIXR_RX_OVF)
        dev_warn(drvdata->dev, "receive overrun error\n");

    if (intr_sr & XPS2_IPIXR_RX_ERR)
        drvdata->flags |= SERIO_PARITY;

    if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
        drvdata->flags |= SERIO_TIMEOUT;

    if (intr_sr & XPS2_IPIXR_RX_FULL) {
        status = xps2_recv(drvdata, &c);

        /* Error, if a byte is not received */
        if (status) {
            dev_err(drvdata->dev,
                "wrong rcvd byte count (%d)\n", status);
        } else {
            serio_interrupt(drvdata->serio, c, drvdata->flags);
            drvdata->flags = 0;
        }
    }

    return IRQ_HANDLED;
}

/*******************/
/* serio callbacks */
/*******************/

static int sxps2_write(struct serio *pserio, unsigned char c)
{
    struct xps2data *drvdata = pserio->port_data;
    unsigned long flags;
    u32 sr;
    int status = -1;

    spin_lock_irqsave(&drvdata->lock, flags);

    /* If the PS/2 transmitter is empty send a byte of data */
    sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
    if (!(sr & XPS2_STATUS_TX_FULL)) {
        out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
        status = 0;
    }

    spin_unlock_irqrestore(&drvdata->lock, flags);

    return status;
}

static int sxps2_open(struct serio *pserio)
{
    struct xps2data *drvdata = pserio->port_data;
    int error;
    u8 c;

    error = request_irq(drvdata->irq, &xps2_interrupt, 0,
                DRIVER_NAME, drvdata);
    if (error) {
        dev_err(drvdata->dev,
            "Couldn't allocate interrupt %d\n", drvdata->irq);
        return error;
    }

    /* start reception by enabling the interrupts */
    out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
    out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
    (void)xps2_recv(drvdata, &c);

    return 0;       /* success */
}

static void sxps2_close(struct serio *pserio)
{
    struct xps2data *drvdata = pserio->port_data;

    /* Disable the PS2 interrupts */
    out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
    out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
    free_irq(drvdata->irq, drvdata);
}

static int __devinit xps2_of_probe(struct platform_device *ofdev)
{
    struct resource r_irq; /* Interrupt resources */
    struct resource r_mem; /* IO mem resources */
    struct xps2data *drvdata;
    struct serio *serio;
    struct device *dev = &ofdev->dev;
    resource_size_t remap_size, phys_addr;
    int error;

    dev_info(dev, "Device Tree Probing \'%s\'\n",
            ofdev->dev.of_node->name);

    /* Get iospace for the device */
    error = of_address_to_resource(ofdev->dev.of_node, 0, &r_mem);
    if (error) {
        dev_err(dev, "invalid address\n");
        return error;
    }

    /* Get IRQ for the device */
    if (!of_irq_to_resource(ofdev->dev.of_node, 0, &r_irq)) {
        dev_err(dev, "no IRQ found\n");
        return -ENODEV;
    }

    drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
    serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
    if (!drvdata || !serio) {
        error = -ENOMEM;
        goto failed1;
    }

    spin_lock_init(&drvdata->lock);
    drvdata->irq = r_irq.start;
    drvdata->serio = serio;
    drvdata->dev = dev;

    phys_addr = r_mem.start;
    remap_size = resource_size(&r_mem);
    if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
        dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
            (unsigned long long)phys_addr);
        error = -EBUSY;
        goto failed1;
    }

    /* Fill in configuration data and add them to the list */
    drvdata->base_address = ioremap(phys_addr, remap_size);
    if (drvdata->base_address == NULL) {
        dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
            (unsigned long long)phys_addr);
        error = -EFAULT;
        goto failed2;
    }

    /* Disable all the interrupts, just in case */
    out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);

    /* Reset the PS2 device and abort any current transaction, to make sure
     * we have the PS2 in a good state */
    out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);

    dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
         (unsigned long long)phys_addr, drvdata->base_address,
         drvdata->irq);

    serio->id.type = SERIO_8042;
    serio->write = sxps2_write;
    serio->open = sxps2_open;
    serio->close = sxps2_close;
    serio->port_data = drvdata;
    serio->dev.parent = dev;
    snprintf(serio->name, sizeof(serio->name),
         "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
    snprintf(serio->phys, sizeof(serio->phys),
         "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);

    serio_register_port(serio);

    platform_set_drvdata(ofdev, drvdata);
    return 0;       /* success */

failed2:
    release_mem_region(phys_addr, remap_size);
failed1:
    kfree(serio);
    kfree(drvdata);

    return error;
}

static int __devexit xps2_of_remove(struct platform_device *of_dev)
{
    struct xps2data *drvdata = platform_get_drvdata(of_dev);
    struct resource r_mem; /* IO mem resources */

    serio_unregister_port(drvdata->serio);
    iounmap(drvdata->base_address);

    /* Get iospace of the device */
    if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
        dev_err(drvdata->dev, "invalid address\n");
    else
        release_mem_region(r_mem.start, resource_size(&r_mem));

    kfree(drvdata);

    platform_set_drvdata(of_dev, NULL);

    return 0;
}

/* Match table for of_platform binding */
static const struct of_device_id xps2_of_match[] __devinitconst = {
    { .compatible = "xlnx,xps-ps2-1.00.a", },
    { /* end of list */ },
};
MODULE_DEVICE_TABLE(of, xps2_of_match);

static struct platform_driver xps2_of_driver = {
    .driver = {
        .name = DRIVER_NAME,
        .owner = THIS_MODULE,
        .of_match_table = xps2_of_match,
    },
    .probe      = xps2_of_probe,
    .remove     = __devexit_p(xps2_of_remove),
};
module_platform_driver(xps2_of_driver);

MODULE_AUTHOR("Xilinx, Inc.");
MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
MODULE_LICENSE("GPL");