net: wireless: bcmdhd: Enable wlan access on resume for all sdio functions
[linux-2.6.git] / drivers / net / ks8842.c
index ee69dea..4a6ae05 100644 (file)
@@ -23,6 +23,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/etherdevice.h>
 #include <linux/ethtool.h>
 #include <linux/ks8842.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/scatterlist.h>
 
 #define DRV_NAME "ks8842"
 
 /* Timberdale specific Registers */
-#define REG_TIMB_RST   0x1c
+#define REG_TIMB_RST           0x1c
+#define REG_TIMB_FIFO          0x20
+#define REG_TIMB_ISR           0x24
+#define REG_TIMB_IER           0x28
+#define REG_TIMB_IAR           0x2C
+#define REQ_TIMB_DMA_RESUME    0x30
 
 /* KS8842 registers */
 
 #define IRQ_RX_ERROR   0x0080
 #define ENABLED_IRQS   (IRQ_LINK_CHANGE | IRQ_TX | IRQ_RX | IRQ_RX_STOPPED | \
                IRQ_TX_STOPPED | IRQ_RX_OVERRUN | IRQ_RX_ERROR)
+/* When running via timberdale in DMA mode, the RX interrupt should be
+   enabled in the KS8842, but not in the FPGA IP, since the IP handles
+   RX DMA internally.
+   TX interrupts are not needed it is handled by the FPGA the driver is
+   notified via DMA callbacks.
+*/
+#define ENABLED_IRQS_DMA_IP    (IRQ_LINK_CHANGE | IRQ_RX_STOPPED | \
+       IRQ_TX_STOPPED | IRQ_RX_OVERRUN | IRQ_RX_ERROR)
+#define ENABLED_IRQS_DMA       (ENABLED_IRQS_DMA_IP | IRQ_RX)
 #define REG_ISR                0x02
 #define REG_RXSR       0x04
 #define RXSR_VALID     0x8000
 #define        MICREL_KS884X           0x01    /* 0=Timeberdale(FPGA), 1=Micrel */
 #define        KS884X_16BIT            0x02    /*  1=16bit, 0=32bit */
 
+#define DMA_BUFFER_SIZE                2048
+
+struct ks8842_tx_dma_ctl {
+       struct dma_chan *chan;
+       struct dma_async_tx_descriptor *adesc;
+       void *buf;
+       struct scatterlist sg;
+       int channel;
+};
+
+struct ks8842_rx_dma_ctl {
+       struct dma_chan *chan;
+       struct dma_async_tx_descriptor *adesc;
+       struct sk_buff  *skb;
+       struct scatterlist sg;
+       struct tasklet_struct tasklet;
+       int channel;
+};
+
+#define KS8842_USE_DMA(adapter) (((adapter)->dma_tx.channel != -1) && \
+        ((adapter)->dma_rx.channel != -1))
+
 struct ks8842_adapter {
        void __iomem    *hw_addr;
        int             irq;
@@ -127,8 +167,19 @@ struct ks8842_adapter {
        spinlock_t      lock; /* spinlock to be interrupt safe */
        struct work_struct timeout_work;
        struct net_device *netdev;
+       struct device *dev;
+       struct ks8842_tx_dma_ctl        dma_tx;
+       struct ks8842_rx_dma_ctl        dma_rx;
 };
 
+static void ks8842_dma_rx_cb(void *data);
+static void ks8842_dma_tx_cb(void *data);
+
+static inline void ks8842_resume_dma(struct ks8842_adapter *adapter)
+{
+       iowrite32(1, adapter->hw_addr + REQ_TIMB_DMA_RESUME);
+}
+
 static inline void ks8842_select_bank(struct ks8842_adapter *adapter, u16 bank)
 {
        iowrite16(bank, adapter->hw_addr + REG_SELECT_BANK);
@@ -270,7 +321,7 @@ static void ks8842_reset_hw(struct ks8842_adapter *adapter)
        /* RX 2 kb high watermark */
        ks8842_write16(adapter, 0, 0x1000, REG_QRFCR);
 
-       /* aggresive back off in half duplex */
+       /* aggressive back off in half duplex */
        ks8842_enable_bits(adapter, 32, 1 << 8, REG_SGCR1);
 
        /* enable no excessive collison drop */
@@ -282,10 +333,6 @@ static void ks8842_reset_hw(struct ks8842_adapter *adapter)
        /* restart port auto-negotiation */
        ks8842_enable_bits(adapter, 49, 1 << 13, REG_P1CR4);
 
-       if (!(adapter->conf_flags & MICREL_KS884X))
-               /* only advertise 10Mbps */
-               ks8842_clear_bits(adapter, 49, 3 << 2, REG_P1CR4);
-
        /* Enable the transmitter */
        ks8842_enable_tx(adapter);
 
@@ -296,8 +343,19 @@ static void ks8842_reset_hw(struct ks8842_adapter *adapter)
        ks8842_write16(adapter, 18, 0xffff, REG_ISR);
 
        /* enable interrupts */
-       ks8842_write16(adapter, 18, ENABLED_IRQS, REG_IER);
-
+       if (KS8842_USE_DMA(adapter)) {
+               /* When running in DMA Mode the RX interrupt is not enabled in
+                  timberdale because RX data is received by DMA callbacks
+                  it must still be enabled in the KS8842 because it indicates
+                  to timberdale when there is RX data for it's DMA FIFOs */
+               iowrite16(ENABLED_IRQS_DMA_IP, adapter->hw_addr + REG_TIMB_IER);
+               ks8842_write16(adapter, 18, ENABLED_IRQS_DMA, REG_IER);
+       } else {
+               if (!(adapter->conf_flags & MICREL_KS884X))
+                       iowrite16(ENABLED_IRQS,
+                               adapter->hw_addr + REG_TIMB_IER);
+               ks8842_write16(adapter, 18, ENABLED_IRQS, REG_IER);
+       }
        /* enable the switch */
        ks8842_write16(adapter, 32, 0x1, REG_SW_ID_AND_ENABLE);
 }
@@ -370,6 +428,53 @@ static inline u16 ks8842_tx_fifo_space(struct ks8842_adapter *adapter)
        return ks8842_read16(adapter, 16, REG_TXMIR) & 0x1fff;
 }
 
+static int ks8842_tx_frame_dma(struct sk_buff *skb, struct net_device *netdev)
+{
+       struct ks8842_adapter *adapter = netdev_priv(netdev);
+       struct ks8842_tx_dma_ctl *ctl = &adapter->dma_tx;
+       u8 *buf = ctl->buf;
+
+       if (ctl->adesc) {
+               netdev_dbg(netdev, "%s: TX ongoing\n", __func__);
+               /* transfer ongoing */
+               return NETDEV_TX_BUSY;
+       }
+
+       sg_dma_len(&ctl->sg) = skb->len + sizeof(u32);
+
+       /* copy data to the TX buffer */
+       /* the control word, enable IRQ, port 1 and the length */
+       *buf++ = 0x00;
+       *buf++ = 0x01; /* Port 1 */
+       *buf++ = skb->len & 0xff;
+       *buf++ = (skb->len >> 8) & 0xff;
+       skb_copy_from_linear_data(skb, buf, skb->len);
+
+       dma_sync_single_range_for_device(adapter->dev,
+               sg_dma_address(&ctl->sg), 0, sg_dma_len(&ctl->sg),
+               DMA_TO_DEVICE);
+
+       /* make sure the length is a multiple of 4 */
+       if (sg_dma_len(&ctl->sg) % 4)
+               sg_dma_len(&ctl->sg) += 4 - sg_dma_len(&ctl->sg) % 4;
+
+       ctl->adesc = ctl->chan->device->device_prep_slave_sg(ctl->chan,
+               &ctl->sg, 1, DMA_TO_DEVICE,
+               DMA_PREP_INTERRUPT | DMA_COMPL_SKIP_SRC_UNMAP);
+       if (!ctl->adesc)
+               return NETDEV_TX_BUSY;
+
+       ctl->adesc->callback_param = netdev;
+       ctl->adesc->callback = ks8842_dma_tx_cb;
+       ctl->adesc->tx_submit(ctl->adesc);
+
+       netdev->stats.tx_bytes += skb->len;
+
+       dev_kfree_skb(skb);
+
+       return NETDEV_TX_OK;
+}
+
 static int ks8842_tx_frame(struct sk_buff *skb, struct net_device *netdev)
 {
        struct ks8842_adapter *adapter = netdev_priv(netdev);
@@ -421,19 +526,132 @@ static int ks8842_tx_frame(struct sk_buff *skb, struct net_device *netdev)
        return NETDEV_TX_OK;
 }
 
+static void ks8842_update_rx_err_counters(struct net_device *netdev, u32 status)
+{
+       netdev_dbg(netdev, "RX error, status: %x\n", status);
+
+       netdev->stats.rx_errors++;
+       if (status & RXSR_TOO_LONG)
+               netdev->stats.rx_length_errors++;
+       if (status & RXSR_CRC_ERROR)
+               netdev->stats.rx_crc_errors++;
+       if (status & RXSR_RUNT)
+               netdev->stats.rx_frame_errors++;
+}
+
+static void ks8842_update_rx_counters(struct net_device *netdev, u32 status,
+       int len)
+{
+       netdev_dbg(netdev, "RX packet, len: %d\n", len);
+
+       netdev->stats.rx_packets++;
+       netdev->stats.rx_bytes += len;
+       if (status & RXSR_MULTICAST)
+               netdev->stats.multicast++;
+}
+
+static int __ks8842_start_new_rx_dma(struct net_device *netdev)
+{
+       struct ks8842_adapter *adapter = netdev_priv(netdev);
+       struct ks8842_rx_dma_ctl *ctl = &adapter->dma_rx;
+       struct scatterlist *sg = &ctl->sg;
+       int err;
+
+       ctl->skb = netdev_alloc_skb(netdev, DMA_BUFFER_SIZE);
+       if (ctl->skb) {
+               sg_init_table(sg, 1);
+               sg_dma_address(sg) = dma_map_single(adapter->dev,
+                       ctl->skb->data, DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
+               err = dma_mapping_error(adapter->dev, sg_dma_address(sg));
+               if (unlikely(err)) {
+                       sg_dma_address(sg) = 0;
+                       goto out;
+               }
+
+               sg_dma_len(sg) = DMA_BUFFER_SIZE;
+
+               ctl->adesc = ctl->chan->device->device_prep_slave_sg(ctl->chan,
+                       sg, 1, DMA_FROM_DEVICE,
+                       DMA_PREP_INTERRUPT | DMA_COMPL_SKIP_SRC_UNMAP);
+
+               if (!ctl->adesc)
+                       goto out;
+
+               ctl->adesc->callback_param = netdev;
+               ctl->adesc->callback = ks8842_dma_rx_cb;
+               ctl->adesc->tx_submit(ctl->adesc);
+       } else {
+               err = -ENOMEM;
+               sg_dma_address(sg) = 0;
+               goto out;
+       }
+
+       return err;
+out:
+       if (sg_dma_address(sg))
+               dma_unmap_single(adapter->dev, sg_dma_address(sg),
+                       DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
+       sg_dma_address(sg) = 0;
+       if (ctl->skb)
+               dev_kfree_skb(ctl->skb);
+
+       ctl->skb = NULL;
+
+       printk(KERN_ERR DRV_NAME": Failed to start RX DMA: %d\n", err);
+       return err;
+}
+
+static void ks8842_rx_frame_dma_tasklet(unsigned long arg)
+{
+       struct net_device *netdev = (struct net_device *)arg;
+       struct ks8842_adapter *adapter = netdev_priv(netdev);
+       struct ks8842_rx_dma_ctl *ctl = &adapter->dma_rx;
+       struct sk_buff *skb = ctl->skb;
+       dma_addr_t addr = sg_dma_address(&ctl->sg);
+       u32 status;
+
+       ctl->adesc = NULL;
+
+       /* kick next transfer going */
+       __ks8842_start_new_rx_dma(netdev);
+
+       /* now handle the data we got */
+       dma_unmap_single(adapter->dev, addr, DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
+
+       status = *((u32 *)skb->data);
+
+       netdev_dbg(netdev, "%s - rx_data: status: %x\n",
+               __func__, status & 0xffff);
+
+       /* check the status */
+       if ((status & RXSR_VALID) && !(status & RXSR_ERROR)) {
+               int len = (status >> 16) & 0x7ff;
+
+               ks8842_update_rx_counters(netdev, status, len);
+
+               /* reserve 4 bytes which is the status word */
+               skb_reserve(skb, 4);
+               skb_put(skb, len);
+
+               skb->protocol = eth_type_trans(skb, netdev);
+               netif_rx(skb);
+       } else {
+               ks8842_update_rx_err_counters(netdev, status);
+               dev_kfree_skb(skb);
+       }
+}
+
 static void ks8842_rx_frame(struct net_device *netdev,
        struct ks8842_adapter *adapter)
 {
-       u16 status16;
        u32 status;
        int len;
 
        if (adapter->conf_flags & KS884X_16BIT) {
-               status16 = ks8842_read16(adapter, 17, REG_QMU_DATA_LO);
-               len  = (int)ks8842_read16(adapter, 17, REG_QMU_DATA_HI);
-               len &= 0xffff;
+               status = ks8842_read16(adapter, 17, REG_QMU_DATA_LO);
+               len = ks8842_read16(adapter, 17, REG_QMU_DATA_HI);
                netdev_dbg(netdev, "%s - rx_data: status: %x\n",
-                          __func__, status16);
+                          __func__, status);
        } else {
                status = ks8842_read32(adapter, 17, REG_QMU_DATA_LO);
                len = (status >> 16) & 0x7ff;
@@ -444,15 +662,11 @@ static void ks8842_rx_frame(struct net_device *netdev,
 
        /* check the status */
        if ((status & RXSR_VALID) && !(status & RXSR_ERROR)) {
-               struct sk_buff *skb = netdev_alloc_skb_ip_align(netdev, len);
+               struct sk_buff *skb = netdev_alloc_skb_ip_align(netdev, len + 3);
 
-               netdev_dbg(netdev, "%s, got package, len: %d\n", __func__, len);
                if (skb) {
 
-                       netdev->stats.rx_packets++;
-                       netdev->stats.rx_bytes += len;
-                       if (status & RXSR_MULTICAST)
-                               netdev->stats.multicast++;
+                       ks8842_update_rx_counters(netdev, status, len);
 
                        if (adapter->conf_flags & KS884X_16BIT) {
                                u16 *data16 = (u16 *)skb_put(skb, len);
@@ -478,16 +692,8 @@ static void ks8842_rx_frame(struct net_device *netdev,
                        netif_rx(skb);
                } else
                        netdev->stats.rx_dropped++;
-       } else {
-               netdev_dbg(netdev, "RX error, status: %x\n", status);
-               netdev->stats.rx_errors++;
-               if (status & RXSR_TOO_LONG)
-                       netdev->stats.rx_length_errors++;
-               if (status & RXSR_CRC_ERROR)
-                       netdev->stats.rx_crc_errors++;
-               if (status & RXSR_RUNT)
-                       netdev->stats.rx_frame_errors++;
-       }
+       } else
+               ks8842_update_rx_err_counters(netdev, status);
 
        /* set high watermark to 3K */
        ks8842_clear_bits(adapter, 0, 1 << 12, REG_QRFCR);
@@ -542,18 +748,30 @@ void ks8842_tasklet(unsigned long arg)
        isr = ks8842_read16(adapter, 18, REG_ISR);
        netdev_dbg(netdev, "%s - ISR: 0x%x\n", __func__, isr);
 
+       /* when running in DMA mode, do not ack RX interrupts, it is handled
+          internally by timberdale, otherwise it's DMA FIFO:s would stop
+       */
+       if (KS8842_USE_DMA(adapter))
+               isr &= ~IRQ_RX;
+
        /* Ack */
        ks8842_write16(adapter, 18, isr, REG_ISR);
 
+       if (!(adapter->conf_flags & MICREL_KS884X))
+               /* Ack in the timberdale IP as well */
+               iowrite32(0x1, adapter->hw_addr + REG_TIMB_IAR);
+
        if (!netif_running(netdev))
                return;
 
        if (isr & IRQ_LINK_CHANGE)
                ks8842_update_link_status(netdev, adapter);
 
-       if (isr & (IRQ_RX | IRQ_RX_ERROR))
+       /* should not get IRQ_RX when running DMA mode */
+       if (isr & (IRQ_RX | IRQ_RX_ERROR) && !KS8842_USE_DMA(adapter))
                ks8842_handle_rx(netdev, adapter);
 
+       /* should only happen when in PIO mode */
        if (isr & IRQ_TX)
                ks8842_handle_tx(netdev, adapter);
 
@@ -572,8 +790,17 @@ void ks8842_tasklet(unsigned long arg)
 
        /* re-enable interrupts, put back the bank selection register */
        spin_lock_irqsave(&adapter->lock, flags);
-       ks8842_write16(adapter, 18, ENABLED_IRQS, REG_IER);
+       if (KS8842_USE_DMA(adapter))
+               ks8842_write16(adapter, 18, ENABLED_IRQS_DMA, REG_IER);
+       else
+               ks8842_write16(adapter, 18, ENABLED_IRQS, REG_IER);
        iowrite16(entry_bank, adapter->hw_addr + REG_SELECT_BANK);
+
+       /* Make sure timberdale continues DMA operations, they are stopped while
+          we are handling the ks8842 because we might change bank */
+       if (KS8842_USE_DMA(adapter))
+               ks8842_resume_dma(adapter);
+
        spin_unlock_irqrestore(&adapter->lock, flags);
 }
 
@@ -589,8 +816,12 @@ static irqreturn_t ks8842_irq(int irq, void *devid)
        netdev_dbg(netdev, "%s - ISR: 0x%x\n", __func__, isr);
 
        if (isr) {
-               /* disable IRQ */
-               ks8842_write16(adapter, 18, 0x00, REG_IER);
+               if (KS8842_USE_DMA(adapter))
+                       /* disable all but RX IRQ, since the FPGA relies on it*/
+                       ks8842_write16(adapter, 18, IRQ_RX, REG_IER);
+               else
+                       /* disable IRQ */
+                       ks8842_write16(adapter, 18, 0x00, REG_IER);
 
                /* schedule tasklet */
                tasklet_schedule(&adapter->tasklet);
@@ -600,9 +831,151 @@ static irqreturn_t ks8842_irq(int irq, void *devid)
 
        iowrite16(entry_bank, adapter->hw_addr + REG_SELECT_BANK);
 
+       /* After an interrupt, tell timberdale to continue DMA operations.
+          DMA is disabled while we are handling the ks8842 because we might
+          change bank */
+       ks8842_resume_dma(adapter);
+
        return ret;
 }
 
+static void ks8842_dma_rx_cb(void *data)
+{
+       struct net_device       *netdev = data;
+       struct ks8842_adapter   *adapter = netdev_priv(netdev);
+
+       netdev_dbg(netdev, "RX DMA finished\n");
+       /* schedule tasklet */
+       if (adapter->dma_rx.adesc)
+               tasklet_schedule(&adapter->dma_rx.tasklet);
+}
+
+static void ks8842_dma_tx_cb(void *data)
+{
+       struct net_device               *netdev = data;
+       struct ks8842_adapter           *adapter = netdev_priv(netdev);
+       struct ks8842_tx_dma_ctl        *ctl = &adapter->dma_tx;
+
+       netdev_dbg(netdev, "TX DMA finished\n");
+
+       if (!ctl->adesc)
+               return;
+
+       netdev->stats.tx_packets++;
+       ctl->adesc = NULL;
+
+       if (netif_queue_stopped(netdev))
+               netif_wake_queue(netdev);
+}
+
+static void ks8842_stop_dma(struct ks8842_adapter *adapter)
+{
+       struct ks8842_tx_dma_ctl *tx_ctl = &adapter->dma_tx;
+       struct ks8842_rx_dma_ctl *rx_ctl = &adapter->dma_rx;
+
+       tx_ctl->adesc = NULL;
+       if (tx_ctl->chan)
+               tx_ctl->chan->device->device_control(tx_ctl->chan,
+                       DMA_TERMINATE_ALL, 0);
+
+       rx_ctl->adesc = NULL;
+       if (rx_ctl->chan)
+               rx_ctl->chan->device->device_control(rx_ctl->chan,
+                       DMA_TERMINATE_ALL, 0);
+
+       if (sg_dma_address(&rx_ctl->sg))
+               dma_unmap_single(adapter->dev, sg_dma_address(&rx_ctl->sg),
+                       DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
+       sg_dma_address(&rx_ctl->sg) = 0;
+
+       dev_kfree_skb(rx_ctl->skb);
+       rx_ctl->skb = NULL;
+}
+
+static void ks8842_dealloc_dma_bufs(struct ks8842_adapter *adapter)
+{
+       struct ks8842_tx_dma_ctl *tx_ctl = &adapter->dma_tx;
+       struct ks8842_rx_dma_ctl *rx_ctl = &adapter->dma_rx;
+
+       ks8842_stop_dma(adapter);
+
+       if (tx_ctl->chan)
+               dma_release_channel(tx_ctl->chan);
+       tx_ctl->chan = NULL;
+
+       if (rx_ctl->chan)
+               dma_release_channel(rx_ctl->chan);
+       rx_ctl->chan = NULL;
+
+       tasklet_kill(&rx_ctl->tasklet);
+
+       if (sg_dma_address(&tx_ctl->sg))
+               dma_unmap_single(adapter->dev, sg_dma_address(&tx_ctl->sg),
+                       DMA_BUFFER_SIZE, DMA_TO_DEVICE);
+       sg_dma_address(&tx_ctl->sg) = 0;
+
+       kfree(tx_ctl->buf);
+       tx_ctl->buf = NULL;
+}
+
+static bool ks8842_dma_filter_fn(struct dma_chan *chan, void *filter_param)
+{
+       return chan->chan_id == (long)filter_param;
+}
+
+static int ks8842_alloc_dma_bufs(struct net_device *netdev)
+{
+       struct ks8842_adapter *adapter = netdev_priv(netdev);
+       struct ks8842_tx_dma_ctl *tx_ctl = &adapter->dma_tx;
+       struct ks8842_rx_dma_ctl *rx_ctl = &adapter->dma_rx;
+       int err;
+
+       dma_cap_mask_t mask;
+
+       dma_cap_zero(mask);
+       dma_cap_set(DMA_SLAVE, mask);
+       dma_cap_set(DMA_PRIVATE, mask);
+
+       sg_init_table(&tx_ctl->sg, 1);
+
+       tx_ctl->chan = dma_request_channel(mask, ks8842_dma_filter_fn,
+                                          (void *)(long)tx_ctl->channel);
+       if (!tx_ctl->chan) {
+               err = -ENODEV;
+               goto err;
+       }
+
+       /* allocate DMA buffer */
+       tx_ctl->buf = kmalloc(DMA_BUFFER_SIZE, GFP_KERNEL);
+       if (!tx_ctl->buf) {
+               err = -ENOMEM;
+               goto err;
+       }
+
+       sg_dma_address(&tx_ctl->sg) = dma_map_single(adapter->dev,
+               tx_ctl->buf, DMA_BUFFER_SIZE, DMA_TO_DEVICE);
+       err = dma_mapping_error(adapter->dev,
+               sg_dma_address(&tx_ctl->sg));
+       if (err) {
+               sg_dma_address(&tx_ctl->sg) = 0;
+               goto err;
+       }
+
+       rx_ctl->chan = dma_request_channel(mask, ks8842_dma_filter_fn,
+                                          (void *)(long)rx_ctl->channel);
+       if (!rx_ctl->chan) {
+               err = -ENODEV;
+               goto err;
+       }
+
+       tasklet_init(&rx_ctl->tasklet, ks8842_rx_frame_dma_tasklet,
+               (unsigned long)netdev);
+
+       return 0;
+err:
+       ks8842_dealloc_dma_bufs(adapter);
+       return err;
+}
 
 /* Netdevice operations */
 
@@ -613,6 +986,25 @@ static int ks8842_open(struct net_device *netdev)
 
        netdev_dbg(netdev, "%s - entry\n", __func__);
 
+       if (KS8842_USE_DMA(adapter)) {
+               err = ks8842_alloc_dma_bufs(netdev);
+
+               if (!err) {
+                       /* start RX dma */
+                       err = __ks8842_start_new_rx_dma(netdev);
+                       if (err)
+                               ks8842_dealloc_dma_bufs(adapter);
+               }
+
+               if (err) {
+                       printk(KERN_WARNING DRV_NAME
+                               ": Failed to initiate DMA, running PIO\n");
+                       ks8842_dealloc_dma_bufs(adapter);
+                       adapter->dma_rx.channel = -1;
+                       adapter->dma_tx.channel = -1;
+               }
+       }
+
        /* reset the HW */
        ks8842_reset_hw(adapter);
 
@@ -638,6 +1030,9 @@ static int ks8842_close(struct net_device *netdev)
 
        cancel_work_sync(&adapter->timeout_work);
 
+       if (KS8842_USE_DMA(adapter))
+               ks8842_dealloc_dma_bufs(adapter);
+
        /* free the irq */
        free_irq(adapter->irq, netdev);
 
@@ -655,6 +1050,17 @@ static netdev_tx_t ks8842_xmit_frame(struct sk_buff *skb,
 
        netdev_dbg(netdev, "%s: entry\n", __func__);
 
+       if (KS8842_USE_DMA(adapter)) {
+               unsigned long flags;
+               ret = ks8842_tx_frame_dma(skb, netdev);
+               /* for now only allow one transfer at the time */
+               spin_lock_irqsave(&adapter->lock, flags);
+               if (adapter->dma_tx.adesc)
+                       netif_stop_queue(netdev);
+               spin_unlock_irqrestore(&adapter->lock, flags);
+               return ret;
+       }
+
        ret = ks8842_tx_frame(skb, netdev);
 
        if (ks8842_tx_fifo_space(adapter) <  netdev->mtu + 8)
@@ -690,6 +1096,10 @@ static void ks8842_tx_timeout_work(struct work_struct *work)
        netdev_dbg(netdev, "%s: entry\n", __func__);
 
        spin_lock_irqsave(&adapter->lock, flags);
+
+       if (KS8842_USE_DMA(adapter))
+               ks8842_stop_dma(adapter);
+
        /* disable interrupts */
        ks8842_write16(adapter, 18, 0, REG_IER);
        ks8842_write16(adapter, 18, 0xFFFF, REG_ISR);
@@ -703,6 +1113,9 @@ static void ks8842_tx_timeout_work(struct work_struct *work)
        ks8842_write_mac_addr(adapter, netdev->dev_addr);
 
        ks8842_update_link_status(netdev, adapter);
+
+       if (KS8842_USE_DMA(adapter))
+               __ks8842_start_new_rx_dma(netdev);
 }
 
 static void ks8842_tx_timeout(struct net_device *netdev)
@@ -762,6 +1175,19 @@ static int __devinit ks8842_probe(struct platform_device *pdev)
                goto err_get_irq;
        }
 
+       adapter->dev = (pdev->dev.parent) ? pdev->dev.parent : &pdev->dev;
+
+       /* DMA is only supported when accessed via timberdale */
+       if (!(adapter->conf_flags & MICREL_KS884X) && pdata &&
+               (pdata->tx_dma_channel != -1) &&
+               (pdata->rx_dma_channel != -1)) {
+               adapter->dma_rx.channel = pdata->rx_dma_channel;
+               adapter->dma_tx.channel = pdata->tx_dma_channel;
+       } else {
+               adapter->dma_rx.channel = -1;
+               adapter->dma_tx.channel = -1;
+       }
+
        tasklet_init(&adapter->tasklet, ks8842_tasklet, (unsigned long)netdev);
        spin_lock_init(&adapter->lock);