--- /dev/null
+/**
+ * drivers/cbus/tahvo-user.c
+ *
+ * Tahvo user space interface functions
+ *
+ * Copyright (C) 2004, 2005 Nokia Corporation
+ *
+ * Written by Mikko Ylinen <mikko.k.ylinen@nokia.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * 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/types.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/poll.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+
+#include <asm/uaccess.h>
+
+#include "tahvo.h"
+
+#include "user_retu_tahvo.h"
+
+/* Maximum size of IRQ node buffer/pool */
+#define TAHVO_MAX_IRQ_BUF_LEN 16
+
+#define PFX "tahvo-user: "
+
+/* Bitmap for marking the interrupt sources as having the handlers */
+static u32 tahvo_irq_bits;
+
+/* For allowing only one user process to subscribe to the tahvo interrupts */
+static struct file *tahvo_irq_subscr = NULL;
+
+/* For poll and IRQ passing */
+struct tahvo_irq {
+ u32 id;
+ struct list_head node;
+};
+
+static spinlock_t tahvo_irqs_lock;
+static struct tahvo_irq *tahvo_irq_block;
+static LIST_HEAD(tahvo_irqs);
+static LIST_HEAD(tahvo_irqs_reserve);
+
+/* Wait queue - used when user wants to read the device */
+DECLARE_WAIT_QUEUE_HEAD(tahvo_user_waitqueue);
+
+/* Semaphore to protect irq subscription sequence */
+static struct mutex tahvo_mutex;
+
+/* This array specifies TAHVO register types (read/write/toggle) */
+static const u8 tahvo_access_bits[] = {
+ 1,
+ 4,
+ 1,
+ 3,
+ 3,
+ 3,
+ 3,
+ 3,
+ 3,
+ 3,
+ 3,
+ 3,
+ 3,
+ 1
+};
+
+/*
+ * The handler for all TAHVO interrupts.
+ *
+ * arg is the interrupt source in TAHVO.
+ */
+static void tahvo_user_irq_handler(unsigned long arg)
+{
+ struct tahvo_irq *irq;
+
+ /* user has to re-enable the interrupt once ready
+ * for receiving them again */
+ tahvo_disable_irq(arg);
+ tahvo_ack_irq(arg);
+
+ spin_lock(&tahvo_irqs_lock);
+ if (list_empty(&tahvo_irqs_reserve)) {
+ spin_unlock(&tahvo_irqs_lock);
+ return;
+ }
+ irq = list_entry((&tahvo_irqs_reserve)->next, struct tahvo_irq, node);
+ irq->id = arg;
+ list_move_tail(&irq->node, &tahvo_irqs);
+ spin_unlock(&tahvo_irqs_lock);
+
+ /* wake up waiting thread */
+ wake_up(&tahvo_user_waitqueue);
+}
+
+/*
+ * This routine sets up the interrupt handler and marks an interrupt source
+ * in TAHVO as a candidate for signal delivery to the user process.
+ */
+static int tahvo_user_subscribe_to_irq(int id, struct file *filp)
+{
+ int ret;
+
+ mutex_lock(&tahvo_mutex);
+ if ((tahvo_irq_subscr != NULL) && (tahvo_irq_subscr != filp)) {
+ mutex_unlock(&tahvo_mutex);
+ return -EBUSY;
+ }
+ /* Store the file pointer of the first user process registering IRQs */
+ tahvo_irq_subscr = filp;
+ mutex_unlock(&tahvo_mutex);
+
+ if (tahvo_irq_bits & (1 << id))
+ return 0;
+
+ ret = tahvo_request_irq(id, tahvo_user_irq_handler, id, "");
+ if (ret < 0)
+ return ret;
+
+ /* Mark that this interrupt has a handler */
+ tahvo_irq_bits |= 1 << id;
+
+ return 0;
+}
+
+/*
+ * Unregister all TAHVO interrupt handlers
+ */
+static void tahvo_unreg_irq_handlers(void)
+{
+ int id;
+
+ if (!tahvo_irq_bits)
+ return;
+
+ for (id = 0; id < MAX_TAHVO_IRQ_HANDLERS; id++)
+ if (tahvo_irq_bits & (1 << id))
+ tahvo_free_irq(id);
+
+ tahvo_irq_bits = 0;
+}
+
+/*
+ * Write to TAHVO register.
+ * Returns 0 upon success, a negative error value otherwise.
+ */
+static int tahvo_user_write_with_mask(u32 field, u16 value)
+{
+ u32 mask;
+ u32 reg;
+ u_short tmp;
+ unsigned long flags;
+
+ mask = MASK(field);
+ reg = REG(field);
+
+ /* Detect bad mask and reg */
+ if (mask == 0 || reg > TAHVO_REG_MAX ||
+ tahvo_access_bits[reg] == READ_ONLY) {
+ printk(KERN_ERR PFX "invalid arguments (reg=%#x, mask=%#x)\n",
+ reg, mask);
+ return -EINVAL;
+ }
+
+ /* Justify value according to mask */
+ while (!(mask & 1)) {
+ value = value << 1;
+ mask = mask >> 1;
+ }
+
+ spin_lock_irqsave(&tahvo_lock, flags);
+ if (tahvo_access_bits[reg] == TOGGLE) {
+ /* No need to detect previous content of register */
+ tmp = 0;
+ } else {
+ /* Read current value of register */
+ tmp = tahvo_read_reg(reg);
+ }
+ /* Generate a new value */
+ tmp = (tmp & ~MASK(field)) | (value & MASK(field));
+ /* Write data to TAHVO */
+ tahvo_write_reg(reg, tmp);
+ spin_unlock_irqrestore(&tahvo_lock, flags);
+
+ return 0;
+}
+
+/*
+ * Read TAHVO register.
+ */
+static u32 tahvo_user_read_with_mask(u32 field)
+{
+ u_short value;
+ u32 mask, reg;
+
+ mask = MASK(field);
+ reg = REG(field);
+
+ /* Detect bad mask and reg */
+ if (mask == 0 || reg > TAHVO_REG_MAX) {
+ printk(KERN_ERR PFX "invalid arguments (reg=%#x, mask=%#x)\n",
+ reg, mask);
+ return -EINVAL;
+ }
+
+ /* Read the register */
+ value = tahvo_read_reg(reg) & mask;
+
+ /* Right justify value */
+ while (!(mask & 1)) {
+ value = value >> 1;
+ mask = mask >> 1;
+ }
+
+ return value;
+}
+
+/*
+ * Close device
+ */
+static int tahvo_close(struct inode *inode, struct file *filp)
+{
+ /* Unregister all interrupts that have been registered */
+ if (tahvo_irq_subscr == filp) {
+ tahvo_unreg_irq_handlers();
+ tahvo_irq_subscr = NULL;
+ }
+
+ return 0;
+}
+
+/*
+ * Device control (ioctl)
+ */
+static int tahvo_ioctl(struct inode *inode, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct retu_tahvo_write_parms par;
+ int ret;
+
+ switch (cmd) {
+ case URT_IOCT_IRQ_SUBSCR:
+ return tahvo_user_subscribe_to_irq(arg, filp);
+ case TAHVO_IOCH_READ:
+ return tahvo_user_read_with_mask(arg);
+ case TAHVO_IOCX_WRITE:
+ ret = copy_from_user(&par, (void __user *) arg, sizeof(par));
+ if (ret)
+ printk(KERN_ERR "copy_from_user failed: %d\n", ret);
+ par.result = tahvo_user_write_with_mask(par.field, par.value);
+ ret = copy_to_user((void __user *) arg, &par, sizeof(par));
+ if (ret)
+ printk(KERN_ERR "copy_to_user failed: %d\n", ret);
+ break;
+ default:
+ return -ENOIOCTLCMD;
+ }
+ return 0;
+}
+
+/*
+ * Read from device
+ */
+static ssize_t tahvo_read(struct file *filp, char *buf, size_t count,
+ loff_t * offp)
+{
+ struct tahvo_irq *irq;
+
+ u32 nr, i;
+
+ /* read not permitted if neither filp nor anyone has registered IRQs */
+ if (tahvo_irq_subscr != filp)
+ return -EPERM;
+
+ if ((count < sizeof(u32)) || ((count % sizeof(u32)) != 0))
+ return -EINVAL;
+
+ nr = count / sizeof(u32);
+
+ for (i = 0; i < nr; i++) {
+ unsigned long flags;
+ u32 irq_id;
+ int ret;
+
+ ret = wait_event_interruptible(tahvo_user_waitqueue,
+ !list_empty(&tahvo_irqs));
+ if (ret < 0)
+ return ret;
+
+ spin_lock_irqsave(&tahvo_irqs_lock, flags);
+ irq = list_entry((&tahvo_irqs)->next, struct tahvo_irq, node);
+ irq_id = irq->id;
+ list_move(&irq->node, &tahvo_irqs_reserve);
+ spin_unlock_irqrestore(&tahvo_irqs_lock, flags);
+
+ ret = copy_to_user(buf + i * sizeof(irq_id), &irq_id,
+ sizeof(irq_id));
+ if (ret)
+ printk(KERN_ERR "copy_to_user failed: %d\n", ret);
+ }
+
+ return count;
+}
+
+/*
+ * Poll method
+ */
+static unsigned tahvo_poll(struct file *filp, struct poll_table_struct *pt)
+{
+ if (!list_empty(&tahvo_irqs))
+ return POLLIN;
+
+ poll_wait(filp, &tahvo_user_waitqueue, pt);
+
+ if (!list_empty(&tahvo_irqs))
+ return POLLIN;
+ else
+ return 0;
+}
+
+static struct file_operations tahvo_user_fileops = {
+ .owner = THIS_MODULE,
+ .ioctl = tahvo_ioctl,
+ .read = tahvo_read,
+ .release = tahvo_close,
+ .poll = tahvo_poll
+};
+
+static struct miscdevice tahvo_device = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "tahvo",
+ .fops = &tahvo_user_fileops
+};
+
+/*
+ * Initialization
+ *
+ * @return 0 if successful, error value otherwise.
+ */
+int tahvo_user_init(void)
+{
+ struct tahvo_irq *irq;
+ int res, i;
+
+ irq = kmalloc(sizeof(*irq) * TAHVO_MAX_IRQ_BUF_LEN, GFP_KERNEL);
+ if (irq == NULL) {
+ printk(KERN_ERR PFX "kmalloc failed\n");
+ return -ENOMEM;
+ }
+ memset(irq, 0, sizeof(*irq) * TAHVO_MAX_IRQ_BUF_LEN);
+ for (i = 0; i < TAHVO_MAX_IRQ_BUF_LEN; i++)
+ list_add(&irq[i].node, &tahvo_irqs_reserve);
+
+ tahvo_irq_block = irq;
+
+ spin_lock_init(&tahvo_irqs_lock);
+ mutex_init(&tahvo_mutex);
+
+ /* Request a misc device */
+ res = misc_register(&tahvo_device);
+ if (res < 0) {
+ printk(KERN_ERR PFX "unable to register misc device for %s\n",
+ tahvo_device.name);
+ kfree(irq);
+ return res;
+ }
+
+ return 0;
+}
+
+/*
+ * Cleanup.
+ */
+void tahvo_user_cleanup(void)
+{
+ /* Unregister our misc device */
+ misc_deregister(&tahvo_device);
+ /* Unregister and disable all TAHVO interrupts */
+ tahvo_unreg_irq_handlers();
+ kfree(tahvo_irq_block);
+}
+
+MODULE_DESCRIPTION("Tahvo ASIC user space functions");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mikko Ylinen");
projects / linux-2.6-omap-h63xx.git / blobdiff