zd1211rw: change interrupt URB buffer to DMA buffer

As might lower beacon update CPU usage.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 25 insertions, 13 deletions

diff --git a/drivers/net/wireless/zd1211rw/zd_usb.c b/drivers/net/wireless/zd1211rw/zd_usb.c
index bf1de04dc9f2..ccdf81ebc4f5 100644
--- a/drivers/net/wireless/zd1211rw/zd_usb.c
+++ b/drivers/net/wireless/zd1211rw/zd_usb.c
@@ -411,7 +411,7 @@ static void int_urb_complete(struct urb *urb)
         case -ENOENT:
         case -ECONNRESET:
         case -EPIPE:
-                goto kfree;
+                return;
         default:
                 goto resubmit;
         }
@@ -443,12 +443,11 @@ static void int_urb_complete(struct urb *urb)
 resubmit:
         r = usb_submit_urb(urb, GFP_ATOMIC);
         if (r) {
-                dev_dbg_f(urb_dev(urb), "resubmit urb %p\n", urb);
-                goto kfree;
+                dev_dbg_f(urb_dev(urb), "error: resubmit urb %p err code %d\n",
+                          urb, r);
+                /* TODO: add worker to reset intr->urb */
         }
         return;
-kfree:
-        kfree(urb->transfer_buffer);
 }
 
 static inline int int_urb_interval(struct usb_device *udev)
@@ -479,9 +478,8 @@ static inline int usb_int_enabled(struct zd_usb *usb)
 int zd_usb_enable_int(struct zd_usb *usb)
 {
         int r;
-        struct usb_device *udev;
+        struct usb_device *udev = zd_usb_to_usbdev(usb);
         struct zd_usb_interrupt *intr = &usb->intr;
-        void *transfer_buffer = NULL;
         struct urb *urb;
 
         dev_dbg_f(zd_usb_dev(usb), "\n");
@@ -502,20 +500,21 @@ int zd_usb_enable_int(struct zd_usb *usb)
         intr->urb = urb;
         spin_unlock_irq(&intr->lock);
 
-        /* TODO: make it a DMA buffer */
         r = -ENOMEM;
-        transfer_buffer = kmalloc(USB_MAX_EP_INT_BUFFER, GFP_KERNEL);
-        if (!transfer_buffer) {
+        intr->buffer = usb_alloc_coherent(udev, USB_MAX_EP_INT_BUFFER,
+                                          GFP_KERNEL, &intr->buffer_dma);
+        if (!intr->buffer) {
                 dev_dbg_f(zd_usb_dev(usb),
                         "couldn't allocate transfer_buffer\n");
                 goto error_set_urb_null;
         }
 
-        udev = zd_usb_to_usbdev(usb);
         usb_fill_int_urb(urb, udev, usb_rcvintpipe(udev, EP_INT_IN),
-                         transfer_buffer, USB_MAX_EP_INT_BUFFER,
+                         intr->buffer, USB_MAX_EP_INT_BUFFER,
                          int_urb_complete, usb,
                          intr->interval);
+        urb->transfer_dma = intr->buffer_dma;
+        urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 
         dev_dbg_f(zd_usb_dev(usb), "submit urb %p\n", intr->urb);
         r = usb_submit_urb(urb, GFP_KERNEL);
@@ -527,7 +526,8 @@ int zd_usb_enable_int(struct zd_usb *usb)
 
         return 0;
 error:
-        kfree(transfer_buffer);
+        usb_free_coherent(udev, USB_MAX_EP_INT_BUFFER,
+                          intr->buffer, intr->buffer_dma);
 error_set_urb_null:
         spin_lock_irq(&intr->lock);
         intr->urb = NULL;
@@ -541,8 +541,11 @@ out:
 void zd_usb_disable_int(struct zd_usb *usb)
 {
         unsigned long flags;
+        struct usb_device *udev = zd_usb_to_usbdev(usb);
         struct zd_usb_interrupt *intr = &usb->intr;
         struct urb *urb;
+        void *buffer;
+        dma_addr_t buffer_dma;
 
         spin_lock_irqsave(&intr->lock, flags);
         urb = intr->urb;
@@ -551,11 +554,18 @@ void zd_usb_disable_int(struct zd_usb *usb)
                 return;
         }
         intr->urb = NULL;
+        buffer = intr->buffer;
+        buffer_dma = intr->buffer_dma;
+        intr->buffer = NULL;
         spin_unlock_irqrestore(&intr->lock, flags);
 
         usb_kill_urb(urb);
         dev_dbg_f(zd_usb_dev(usb), "urb %p killed\n", urb);
         usb_free_urb(urb);
+
+        if (buffer)
+                usb_free_coherent(udev, USB_MAX_EP_INT_BUFFER,
+                                  buffer, buffer_dma);
 }
 
 static void handle_rx_packet(struct zd_usb *usb, const u8 *buffer,
diff --git a/drivers/net/wireless/zd1211rw/zd_usb.h b/drivers/net/wireless/zd1211rw/zd_usb.h
index 2ed48ae3e604..24db0dd68421 100644
--- a/drivers/net/wireless/zd1211rw/zd_usb.h
+++ b/drivers/net/wireless/zd1211rw/zd_usb.h
@@ -162,6 +162,8 @@ struct zd_usb_interrupt {
         struct read_regs_int read_regs;
         spinlock_t lock;
         struct urb *urb;
+        void *buffer;
+        dma_addr_t buffer_dma;
         int interval;
         u8 read_regs_enabled:1;
 };