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>

diff --git a/drivers/net/wireless/zd1211rw/zd_usb.c b/drivers/net/wireless/zd1211rw/zd_usb.c
index bf1de04..ccdf81e 100644 (file)
--- 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 2ed48ae..24db0dd 100644 (file)
--- 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;
 };