Misc: phantom, improved data passing

This new version guarantees amb_bit switch in small enough intervals, so that
the device won't stop working in the middle of a movement anymore.  However it
preserves old (openhaptics) functionality.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 81 insertions, 19 deletions

diff --git a/drivers/misc/phantom.c b/drivers/misc/phantom.c
index bc532ac8b7d8..cd221fd0fb94 100644
--- a/drivers/misc/phantom.c
+++ b/drivers/misc/phantom.c
@@ -25,13 +25,14 @@
 #include <asm/atomic.h>
 #include <asm/io.h>
 
-#define PHANTOM_VERSION         "n0.9.5"
+#define PHANTOM_VERSION         "n0.9.7"
 
 #define PHANTOM_MAX_MINORS      8
 
 #define PHN_IRQCTL              0x4c    /* irq control in caddr space */
 
 #define PHB_RUNNING             1
+#define PHB_NOT_OH              2
 
 static struct class *phantom_class;
 static int phantom_major;
@@ -48,7 +49,11 @@ struct phantom_device {
         struct cdev cdev;
 
         struct mutex open_lock;
-        spinlock_t ioctl_lock;
+        spinlock_t regs_lock;
+
+        /* used in NOT_OH mode */
+        struct phm_regs oregs;
+        u32 ctl_reg;
 };
 
 static unsigned char phantom_devices[PHANTOM_MAX_MINORS];
@@ -83,6 +88,7 @@ static long phantom_ioctl(struct file *file, unsigned int cmd,
         struct phm_regs rs;
         struct phm_reg r;
         void __user *argp = (void __user *)arg;
+        unsigned long flags;
         unsigned int i;
 
         if (_IOC_TYPE(cmd) != PH_IOC_MAGIC ||
@@ -97,32 +103,45 @@ static long phantom_ioctl(struct file *file, unsigned int cmd,
                 if (r.reg > 7)
                         return -EINVAL;
 
-                spin_lock(&dev->ioctl_lock);
+                spin_lock_irqsave(&dev->regs_lock, flags);
                 if (r.reg == PHN_CONTROL && (r.value & PHN_CTL_IRQ) &&
                                 phantom_status(dev, dev->status | PHB_RUNNING)){
-                        spin_unlock(&dev->ioctl_lock);
+                        spin_unlock_irqrestore(&dev->regs_lock, flags);
                         return -ENODEV;
                 }
 
                 pr_debug("phantom: writing %x to %u\n", r.value, r.reg);
+
+                /* preserve amp bit (don't allow to change it when in NOT_OH) */
+                if (r.reg == PHN_CONTROL && (dev->status & PHB_NOT_OH)) {
+                        r.value &= ~PHN_CTL_AMP;
+                        r.value |= dev->ctl_reg & PHN_CTL_AMP;
+                        dev->ctl_reg = r.value;
+                }
+
                 iowrite32(r.value, dev->iaddr + r.reg);
                 ioread32(dev->iaddr); /* PCI posting */
 
                 if (r.reg == PHN_CONTROL && !(r.value & PHN_CTL_IRQ))
                         phantom_status(dev, dev->status & ~PHB_RUNNING);
-                spin_unlock(&dev->ioctl_lock);
+                spin_unlock_irqrestore(&dev->regs_lock, flags);
                 break;
         case PHN_SET_REGS:
                 if (copy_from_user(&rs, argp, sizeof(rs)))
                         return -EFAULT;
 
                 pr_debug("phantom: SRS %u regs %x\n", rs.count, rs.mask);
-                spin_lock(&dev->ioctl_lock);
-                for (i = 0; i < min(rs.count, 8U); i++)
-                        if ((1 << i) & rs.mask)
-                                iowrite32(rs.values[i], dev->oaddr + i);
-                ioread32(dev->iaddr); /* PCI posting */
-                spin_unlock(&dev->ioctl_lock);
+                spin_lock_irqsave(&dev->regs_lock, flags);
+                if (dev->status & PHB_NOT_OH)
+                        memcpy(&dev->oregs, &rs, sizeof(rs));
+                else {
+                        u32 m = min(rs.count, 8U);
+                        for (i = 0; i < m; i++)
+                                if (rs.mask & BIT(i))
+                                        iowrite32(rs.values[i], dev->oaddr + i);
+                        ioread32(dev->iaddr); /* PCI posting */
+                }
+                spin_unlock_irqrestore(&dev->regs_lock, flags);
                 break;
         case PHN_GET_REG:
                 if (copy_from_user(&r, argp, sizeof(r)))
@@ -136,20 +155,35 @@ static long phantom_ioctl(struct file *file, unsigned int cmd,
                 if (copy_to_user(argp, &r, sizeof(r)))
                         return -EFAULT;
                 break;
-        case PHN_GET_REGS:
+        case PHN_GET_REGS: {
+                u32 m;
+
                 if (copy_from_user(&rs, argp, sizeof(rs)))
                         return -EFAULT;
 
+                m = min(rs.count, 8U);
+
                 pr_debug("phantom: GRS %u regs %x\n", rs.count, rs.mask);
-                spin_lock(&dev->ioctl_lock);
-                for (i = 0; i < min(rs.count, 8U); i++)
-                        if ((1 << i) & rs.mask)
+                spin_lock_irqsave(&dev->regs_lock, flags);
+                for (i = 0; i < m; i++)
+                        if (rs.mask & BIT(i))
                                 rs.values[i] = ioread32(dev->iaddr + i);
-                spin_unlock(&dev->ioctl_lock);
+                spin_unlock_irqrestore(&dev->regs_lock, flags);
 
                 if (copy_to_user(argp, &rs, sizeof(rs)))
                         return -EFAULT;
                 break;
+        } case PHN_NOT_OH:
+                spin_lock_irqsave(&dev->regs_lock, flags);
+                if (dev->status & PHB_RUNNING) {
+                        printk(KERN_ERR "phantom: you need to set NOT_OH "
+                                        "before you start the device!\n");
+                        spin_unlock_irqrestore(&dev->regs_lock, flags);
+                        return -EINVAL;
+                }
+                dev->status |= PHB_NOT_OH;
+                spin_unlock_irqrestore(&dev->regs_lock, flags);
+                break;
         default:
                 return -ENOTTY;
         }
@@ -172,8 +206,11 @@ static int phantom_open(struct inode *inode, struct file *file)
                 return -EINVAL;
         }
 
+        WARN_ON(dev->status & PHB_NOT_OH);
+
         file->private_data = dev;
 
+        atomic_set(&dev->counter, 0);
         dev->opened++;
         mutex_unlock(&dev->open_lock);
 
@@ -188,6 +225,7 @@ static int phantom_release(struct inode *inode, struct file *file)
 
         dev->opened = 0;
         phantom_status(dev, dev->status & ~PHB_RUNNING);
+        dev->status &= ~PHB_NOT_OH;
 
         mutex_unlock(&dev->open_lock);
 
@@ -221,12 +259,32 @@ static struct file_operations phantom_file_ops = {
 static irqreturn_t phantom_isr(int irq, void *data)
 {
         struct phantom_device *dev = data;
+        unsigned int i;
+        u32 ctl;
 
-        if (!(ioread32(dev->iaddr + PHN_CONTROL) & PHN_CTL_IRQ))
+        spin_lock(&dev->regs_lock);
+        ctl = ioread32(dev->iaddr + PHN_CONTROL);
+        if (!(ctl & PHN_CTL_IRQ)) {
+                spin_unlock(&dev->regs_lock);
                 return IRQ_NONE;
+        }
 
         iowrite32(0, dev->iaddr);
         iowrite32(0xc0, dev->iaddr);
+
+        if (dev->status & PHB_NOT_OH) {
+                struct phm_regs *r = &dev->oregs;
+                u32 m = min(r->count, 8U);
+
+                for (i = 0; i < m; i++)
+                        if (r->mask & BIT(i))
+                                iowrite32(r->values[i], dev->oaddr + i);
+
+                dev->ctl_reg ^= PHN_CTL_AMP;
+                iowrite32(dev->ctl_reg, dev->iaddr + PHN_CONTROL);
+        }
+        spin_unlock(&dev->regs_lock);
+
         ioread32(dev->iaddr); /* PCI posting */
 
         atomic_inc(&dev->counter);
@@ -298,7 +356,7 @@ static int __devinit phantom_probe(struct pci_dev *pdev,
         }
 
         mutex_init(&pht->open_lock);
-        spin_lock_init(&pht->ioctl_lock);
+        spin_lock_init(&pht->regs_lock);
         init_waitqueue_head(&pht->wait);
         cdev_init(&pht->cdev, &phantom_file_ops);
         pht->cdev.owner = THIS_MODULE;
diff --git a/include/linux/phantom.h b/include/linux/phantom.h
index d3ebbfae6903..96f4048a6cc3 100644
--- a/include/linux/phantom.h
+++ b/include/linux/phantom.h
@@ -30,7 +30,11 @@ struct phm_regs {
 #define PHN_SET_REG             _IOW (PH_IOC_MAGIC, 1, struct phm_reg *)
 #define PHN_GET_REGS            _IOWR(PH_IOC_MAGIC, 2, struct phm_regs *)
 #define PHN_SET_REGS            _IOW (PH_IOC_MAGIC, 3, struct phm_regs *)
-#define PH_IOC_MAXNR            3
+/* this ioctl tells the driver, that the caller is not OpenHaptics and might
+ * use improved registers update (no more phantom switchoffs when using
+ * libphantom) */
+#define PHN_NOT_OH              _IO  (PH_IOC_MAGIC, 4)
+#define PH_IOC_MAXNR            4
 
 #define PHN_CONTROL             0x6     /* control byte in iaddr space */
 #define PHN_CTL_AMP             0x1     /*   switch after torques change */