Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 2074 insertions, 0 deletions

diff --git a/drivers/net/wan/dscc4.c b/drivers/net/wan/dscc4.c
new file mode 100644
index 00000000000..520a77a798e
--- /dev/null
+++ b/drivers/net/wan/dscc4.c
@@ -0,0 +1,2074 @@
+/*
+ * drivers/net/wan/dscc4/dscc4.c: a DSCC4 HDLC driver for Linux
+ *
+ * This software may be used and distributed according to the terms of the
+ * GNU General Public License.
+ *
+ * The author may be reached as romieu@cogenit.fr.
+ * Specific bug reports/asian food will be welcome.
+ *
+ * Special thanks to the nice people at CS-Telecom for the hardware and the
+ * access to the test/measure tools.
+ *
+ *
+ *                             Theory of Operation
+ *
+ * I. Board Compatibility
+ *
+ * This device driver is designed for the Siemens PEB20534 4 ports serial
+ * controller as found on Etinc PCISYNC cards. The documentation for the
+ * chipset is available at http://www.infineon.com:
+ * - Data Sheet "DSCC4, DMA Supported Serial Communication Controller with
+ * 4 Channels, PEB 20534 Version 2.1, PEF 20534 Version 2.1";
+ * - Application Hint "Management of DSCC4 on-chip FIFO resources".
+ * - Errata sheet DS5 (courtesy of Michael Skerritt).
+ * Jens David has built an adapter based on the same chipset. Take a look
+ * at http://www.afthd.tu-darmstadt.de/~dg1kjd/pciscc4 for a specific
+ * driver.
+ * Sample code (2 revisions) is available at Infineon.
+ *
+ * II. Board-specific settings
+ *
+ * Pcisync can transmit some clock signal to the outside world on the
+ * *first two* ports provided you put a quartz and a line driver on it and
+ * remove the jumpers. The operation is described on Etinc web site. If you
+ * go DCE on these ports, don't forget to use an adequate cable.
+ *
+ * Sharing of the PCI interrupt line for this board is possible.
+ *
+ * III. Driver operation
+ *
+ * The rx/tx operations are based on a linked list of descriptors. The driver
+ * doesn't use HOLD mode any more. HOLD mode is definitely buggy and the more
+ * I tried to fix it, the more it started to look like (convoluted) software
+ * mutation of LxDA method. Errata sheet DS5 suggests to use LxDA: consider
+ * this a rfc2119 MUST.
+ *
+ * Tx direction
+ * When the tx ring is full, the xmit routine issues a call to netdev_stop.
+ * The device is supposed to be enabled again during an ALLS irq (we could
+ * use HI but as it's easy to lose events, it's fscked).
+ *
+ * Rx direction
+ * The received frames aren't supposed to span over multiple receiving areas.
+ * I may implement it some day but it isn't the highest ranked item.
+ *
+ * IV. Notes
+ * The current error (XDU, RFO) recovery code is untested.
+ * So far, RDO takes his RX channel down and the right sequence to enable it
+ * again is still a mistery. If RDO happens, plan a reboot. More details
+ * in the code (NB: as this happens, TX still works).
+ * Don't mess the cables during operation, especially on DTE ports. I don't
+ * suggest it for DCE either but at least one can get some messages instead
+ * of a complete instant freeze.
+ * Tests are done on Rev. 20 of the silicium. The RDO handling changes with
+ * the documentation/chipset releases.
+ *
+ * TODO:
+ * - test X25.
+ * - use polling at high irq/s,
+ * - performance analysis,
+ * - endianness.
+ *
+ * 2001/12/10	Daniela Squassoni  <daniela@cyclades.com>
+ * - Contribution to support the new generic HDLC layer.
+ *
+ * 2002/01	Ueimor
+ * - old style interface removal
+ * - dscc4_release_ring fix (related to DMA mapping)
+ * - hard_start_xmit fix (hint: TxSizeMax)
+ * - misc crapectomy.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/list.h>
+#include <linux/ioport.h>
+#include <linux/pci.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+
+#include <asm/system.h>
+#include <asm/cache.h>
+#include <asm/byteorder.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+
+#include <linux/init.h>
+#include <linux/string.h>
+
+#include <linux/if_arp.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/delay.h>
+#include <net/syncppp.h>
+#include <linux/hdlc.h>
+
+/* Version */
+static const char version[] = "$Id: dscc4.c,v 1.173 2003/09/20 23:55:34 romieu Exp $ for Linux\n";
+static int debug;
+static int quartz;
+
+#ifdef CONFIG_DSCC4_PCI_RST
+static DECLARE_MUTEX(dscc4_sem);
+static u32 dscc4_pci_config_store[16];
+#endif
+
+#define	DRV_NAME	"dscc4"
+
+#undef DSCC4_POLLING
+
+/* Module parameters */
+
+MODULE_AUTHOR("Maintainer: Francois Romieu <romieu@cogenit.fr>");
+MODULE_DESCRIPTION("Siemens PEB20534 PCI Controler");
+MODULE_LICENSE("GPL");
+module_param(debug, int, 0);
+MODULE_PARM_DESC(debug,"Enable/disable extra messages");
+module_param(quartz, int, 0);
+MODULE_PARM_DESC(quartz,"If present, on-board quartz frequency (Hz)");
+
+/* Structures */
+
+struct thingie {
+	int define;
+	u32 bits;
+};
+
+struct TxFD {
+	u32 state;
+	u32 next;
+	u32 data;
+	u32 complete;
+	u32 jiffies; /* Allows sizeof(TxFD) == sizeof(RxFD) + extra hack */
+};
+
+struct RxFD {
+	u32 state1;
+	u32 next;
+	u32 data;
+	u32 state2;
+	u32 end;
+};
+
+#define DUMMY_SKB_SIZE		64
+#define TX_LOW			8
+#define TX_RING_SIZE		32
+#define RX_RING_SIZE		32
+#define TX_TOTAL_SIZE		TX_RING_SIZE*sizeof(struct TxFD)
+#define RX_TOTAL_SIZE		RX_RING_SIZE*sizeof(struct RxFD)
+#define IRQ_RING_SIZE		64		/* Keep it a multiple of 32 */
+#define TX_TIMEOUT		(HZ/10)
+#define DSCC4_HZ_MAX		33000000
+#define BRR_DIVIDER_MAX		64*0x00004000	/* Cf errata DS5 p.10 */
+#define dev_per_card		4
+#define SCC_REGISTERS_MAX	23		/* Cf errata DS5 p.4 */
+
+#define SOURCE_ID(flags)	(((flags) >> 28) & 0x03)
+#define TO_SIZE(state)		(((state) >> 16) & 0x1fff)
+
+/*
+ * Given the operating range of Linux HDLC, the 2 defines below could be
+ * made simpler. However they are a fine reminder for the limitations of
+ * the driver: it's better to stay < TxSizeMax and < RxSizeMax.
+ */
+#define TO_STATE_TX(len)	cpu_to_le32(((len) & TxSizeMax) << 16)
+#define TO_STATE_RX(len)	cpu_to_le32((RX_MAX(len) % RxSizeMax) << 16)
+#define RX_MAX(len)		((((len) >> 5) + 1) << 5)	/* Cf RLCR */
+#define SCC_REG_START(dpriv)	(SCC_START+(dpriv->dev_id)*SCC_OFFSET)
+
+struct dscc4_pci_priv {
+        u32 *iqcfg;
+        int cfg_cur;
+        spinlock_t lock;
+        struct pci_dev *pdev;
+
+        struct dscc4_dev_priv *root;
+        dma_addr_t iqcfg_dma;
+	u32 xtal_hz;
+};
+
+struct dscc4_dev_priv {
+        struct sk_buff *rx_skbuff[RX_RING_SIZE];
+        struct sk_buff *tx_skbuff[TX_RING_SIZE];
+
+        struct RxFD *rx_fd;
+        struct TxFD *tx_fd;
+        u32 *iqrx;
+        u32 *iqtx;
+
+	/* FIXME: check all the volatile are required */
+        volatile u32 tx_current;
+        u32 rx_current;
+        u32 iqtx_current;
+        u32 iqrx_current;
+
+        volatile u32 tx_dirty;
+        volatile u32 ltda;
+        u32 rx_dirty;
+        u32 lrda;
+
+        dma_addr_t tx_fd_dma;
+        dma_addr_t rx_fd_dma;
+        dma_addr_t iqtx_dma;
+        dma_addr_t iqrx_dma;
+
+	u32 scc_regs[SCC_REGISTERS_MAX]; /* Cf errata DS5 p.4 */
+
+	struct timer_list timer;
+
+        struct dscc4_pci_priv *pci_priv;
+        spinlock_t lock;
+
+        int dev_id;
+	volatile u32 flags;
+	u32 timer_help;
+
+	unsigned short encoding;
+	unsigned short parity;
+	struct net_device *dev;
+	sync_serial_settings settings;
+	void __iomem *base_addr;
+	u32 __pad __attribute__ ((aligned (4)));
+};
+
+/* GLOBAL registers definitions */
+#define GCMDR   0x00
+#define GSTAR   0x04
+#define GMODE   0x08
+#define IQLENR0 0x0C
+#define IQLENR1 0x10
+#define IQRX0   0x14
+#define IQTX0   0x24
+#define IQCFG   0x3c
+#define FIFOCR1 0x44
+#define FIFOCR2 0x48
+#define FIFOCR3 0x4c
+#define FIFOCR4 0x34
+#define CH0CFG  0x50
+#define CH0BRDA 0x54
+#define CH0BTDA 0x58
+#define CH0FRDA 0x98
+#define CH0FTDA 0xb0
+#define CH0LRDA 0xc8
+#define CH0LTDA 0xe0
+
+/* SCC registers definitions */
+#define SCC_START	0x0100
+#define SCC_OFFSET      0x80
+#define CMDR    0x00
+#define STAR    0x04
+#define CCR0    0x08
+#define CCR1    0x0c
+#define CCR2    0x10
+#define BRR     0x2C
+#define RLCR    0x40
+#define IMR     0x54
+#define ISR     0x58
+
+#define GPDIR	0x0400
+#define GPDATA	0x0404
+#define GPIM	0x0408
+
+/* Bit masks */
+#define EncodingMask	0x00700000
+#define CrcMask		0x00000003
+
+#define IntRxScc0	0x10000000
+#define IntTxScc0	0x01000000
+
+#define TxPollCmd	0x00000400
+#define RxActivate	0x08000000
+#define MTFi		0x04000000
+#define Rdr		0x00400000
+#define Rdt		0x00200000
+#define Idr		0x00100000
+#define Idt		0x00080000
+#define TxSccRes	0x01000000
+#define RxSccRes	0x00010000
+#define TxSizeMax	0x1fff		/* Datasheet DS1 - 11.1.1.1 */
+#define RxSizeMax	0x1ffc		/* Datasheet DS1 - 11.1.2.1 */
+
+#define Ccr0ClockMask	0x0000003f
+#define Ccr1LoopMask	0x00000200
+#define IsrMask		0x000fffff
+#define BrrExpMask	0x00000f00
+#define BrrMultMask	0x0000003f
+#define EncodingMask	0x00700000
+#define Hold		0x40000000
+#define SccBusy		0x10000000
+#define PowerUp		0x80000000
+#define Vis		0x00001000
+#define FrameOk		(FrameVfr | FrameCrc)
+#define FrameVfr	0x80
+#define FrameRdo	0x40
+#define FrameCrc	0x20
+#define FrameRab	0x10
+#define FrameAborted	0x00000200
+#define FrameEnd	0x80000000
+#define DataComplete	0x40000000
+#define LengthCheck	0x00008000
+#define SccEvt		0x02000000
+#define NoAck		0x00000200
+#define Action		0x00000001
+#define HiDesc		0x20000000
+
+/* SCC events */
+#define RxEvt		0xf0000000
+#define TxEvt		0x0f000000
+#define Alls		0x00040000
+#define Xdu		0x00010000
+#define Cts		0x00004000
+#define Xmr		0x00002000
+#define Xpr		0x00001000
+#define Rdo		0x00000080
+#define Rfs		0x00000040
+#define Cd		0x00000004
+#define Rfo		0x00000002
+#define Flex		0x00000001
+
+/* DMA core events */
+#define Cfg		0x00200000
+#define Hi		0x00040000
+#define Fi		0x00020000
+#define Err		0x00010000
+#define Arf		0x00000002
+#define ArAck		0x00000001
+
+/* State flags */
+#define Ready		0x00000000
+#define NeedIDR		0x00000001
+#define NeedIDT		0x00000002
+#define RdoSet		0x00000004
+#define FakeReset	0x00000008
+
+/* Don't mask RDO. Ever. */
+#ifdef DSCC4_POLLING
+#define EventsMask	0xfffeef7f
+#else
+#define EventsMask	0xfffa8f7a
+#endif
+
+/* Functions prototypes */
+static void dscc4_rx_irq(struct dscc4_pci_priv *, struct dscc4_dev_priv *);
+static void dscc4_tx_irq(struct dscc4_pci_priv *, struct dscc4_dev_priv *);
+static int dscc4_found1(struct pci_dev *, void __iomem *ioaddr);
+static int dscc4_init_one(struct pci_dev *, const struct pci_device_id *ent);
+static int dscc4_open(struct net_device *);
+static int dscc4_start_xmit(struct sk_buff *, struct net_device *);
+static int dscc4_close(struct net_device *);
+static int dscc4_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
+static int dscc4_init_ring(struct net_device *);
+static void dscc4_release_ring(struct dscc4_dev_priv *);
+static void dscc4_timer(unsigned long);
+static void dscc4_tx_timeout(struct net_device *);
+static irqreturn_t dscc4_irq(int irq, void *dev_id, struct pt_regs *ptregs);
+static int dscc4_hdlc_attach(struct net_device *, unsigned short, unsigned short);
+static int dscc4_set_iface(struct dscc4_dev_priv *, struct net_device *);
+#ifdef DSCC4_POLLING
+static int dscc4_tx_poll(struct dscc4_dev_priv *, struct net_device *);
+#endif
+
+static inline struct dscc4_dev_priv *dscc4_priv(struct net_device *dev)
+{
+	return dev_to_hdlc(dev)->priv;
+}
+
+static inline struct net_device *dscc4_to_dev(struct dscc4_dev_priv *p)
+{
+	return p->dev;
+}
+
+static void scc_patchl(u32 mask, u32 value, struct dscc4_dev_priv *dpriv,
+			struct net_device *dev, int offset)
+{
+	u32 state;
+
+	/* Cf scc_writel for concern regarding thread-safety */
+	state = dpriv->scc_regs[offset >> 2];
+	state &= ~mask;
+	state |= value;
+	dpriv->scc_regs[offset >> 2] = state;
+	writel(state, dpriv->base_addr + SCC_REG_START(dpriv) + offset);
+}
+
+static void scc_writel(u32 bits, struct dscc4_dev_priv *dpriv,
+		       struct net_device *dev, int offset)
+{
+	/*
+	 * Thread-UNsafe.
+	 * As of 2002/02/16, there are no thread racing for access.
+	 */
+	dpriv->scc_regs[offset >> 2] = bits;
+	writel(bits, dpriv->base_addr + SCC_REG_START(dpriv) + offset);
+}
+
+static inline u32 scc_readl(struct dscc4_dev_priv *dpriv, int offset)
+{
+	return dpriv->scc_regs[offset >> 2];
+}
+
+static u32 scc_readl_star(struct dscc4_dev_priv *dpriv, struct net_device *dev)
+{
+	/* Cf errata DS5 p.4 */
+	readl(dpriv->base_addr + SCC_REG_START(dpriv) + STAR);
+	return readl(dpriv->base_addr + SCC_REG_START(dpriv) + STAR);
+}
+
+static inline void dscc4_do_tx(struct dscc4_dev_priv *dpriv,
+			       struct net_device *dev)
+{
+	dpriv->ltda = dpriv->tx_fd_dma +
+                      ((dpriv->tx_current-1)%TX_RING_SIZE)*sizeof(struct TxFD);
+	writel(dpriv->ltda, dpriv->base_addr + CH0LTDA + dpriv->dev_id*4);
+	/* Flush posted writes *NOW* */
+	readl(dpriv->base_addr + CH0LTDA + dpriv->dev_id*4);
+}
+
+static inline void dscc4_rx_update(struct dscc4_dev_priv *dpriv,
+				   struct net_device *dev)
+{
+	dpriv->lrda = dpriv->rx_fd_dma +
+		      ((dpriv->rx_dirty - 1)%RX_RING_SIZE)*sizeof(struct RxFD);
+	writel(dpriv->lrda, dpriv->base_addr + CH0LRDA + dpriv->dev_id*4);
+}
+
+static inline unsigned int dscc4_tx_done(struct dscc4_dev_priv *dpriv)
+{
+	return dpriv->tx_current == dpriv->tx_dirty;
+}
+
+static inline unsigned int dscc4_tx_quiescent(struct dscc4_dev_priv *dpriv,
+					      struct net_device *dev)
+{
+	return readl(dpriv->base_addr + CH0FTDA + dpriv->dev_id*4) == dpriv->ltda;
+}
+
+int state_check(u32 state, struct dscc4_dev_priv *dpriv, struct net_device *dev,
+		const char *msg)
+{
+	int ret = 0;
+
+	if (debug > 1) {
+	if (SOURCE_ID(state) != dpriv->dev_id) {
+		printk(KERN_DEBUG "%s (%s): Source Id=%d, state=%08x\n",
+		       dev->name, msg, SOURCE_ID(state), state );
+			ret = -1;
+	}
+	if (state & 0x0df80c00) {
+		printk(KERN_DEBUG "%s (%s): state=%08x (UFO alert)\n",
+		       dev->name, msg, state);
+			ret = -1;
+	}
+	}
+	return ret;
+}
+
+void dscc4_tx_print(struct net_device *dev, struct dscc4_dev_priv *dpriv,
+		    char *msg)
+{
+	printk(KERN_DEBUG "%s: tx_current=%02d tx_dirty=%02d (%s)\n",
+	       dev->name, dpriv->tx_current, dpriv->tx_dirty, msg);
+}
+
+static void dscc4_release_ring(struct dscc4_dev_priv *dpriv)
+{
+	struct pci_dev *pdev = dpriv->pci_priv->pdev;
+	struct TxFD *tx_fd = dpriv->tx_fd;
+	struct RxFD *rx_fd = dpriv->rx_fd;
+	struct sk_buff **skbuff;
+	int i;
+
+	pci_free_consistent(pdev, TX_TOTAL_SIZE, tx_fd, dpriv->tx_fd_dma);
+	pci_free_consistent(pdev, RX_TOTAL_SIZE, rx_fd, dpriv->rx_fd_dma);
+
+	skbuff = dpriv->tx_skbuff;
+	for (i = 0; i < TX_RING_SIZE; i++) {
+		if (*skbuff) {
+			pci_unmap_single(pdev, tx_fd->data, (*skbuff)->len,
+				PCI_DMA_TODEVICE);
+			dev_kfree_skb(*skbuff);
+		}
+		skbuff++;
+		tx_fd++;
+	}
+
+	skbuff = dpriv->rx_skbuff;
+	for (i = 0; i < RX_RING_SIZE; i++) {
+		if (*skbuff) {
+			pci_unmap_single(pdev, rx_fd->data,
+				RX_MAX(HDLC_MAX_MRU), PCI_DMA_FROMDEVICE);
+			dev_kfree_skb(*skbuff);
+		}
+		skbuff++;
+		rx_fd++;
+	}
+}
+
+inline int try_get_rx_skb(struct dscc4_dev_priv *dpriv, struct net_device *dev)
+{
+	unsigned int dirty = dpriv->rx_dirty%RX_RING_SIZE;
+	struct RxFD *rx_fd = dpriv->rx_fd + dirty;
+	const int len = RX_MAX(HDLC_MAX_MRU);
+	struct sk_buff *skb;
+	int ret = 0;
+
+	skb = dev_alloc_skb(len);
+	dpriv->rx_skbuff[dirty] = skb;
+	if (skb) {
+		skb->protocol = hdlc_type_trans(skb, dev);
+		rx_fd->data = pci_map_single(dpriv->pci_priv->pdev, skb->data,
+					     len, PCI_DMA_FROMDEVICE);
+	} else {
+		rx_fd->data = (u32) NULL;
+		ret = -1;
+	}
+	return ret;
+}
+
+/*
+ * IRQ/thread/whatever safe
+ */
+static int dscc4_wait_ack_cec(struct dscc4_dev_priv *dpriv,
+			      struct net_device *dev, char *msg)
+{
+	s8 i = 0;
+
+	do {
+		if (!(scc_readl_star(dpriv, dev) & SccBusy)) {
+			printk(KERN_DEBUG "%s: %s ack (%d try)\n", dev->name,
+			       msg, i);
+			goto done;
+		}
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule_timeout(10);
+		rmb();
+	} while (++i > 0);
+	printk(KERN_ERR "%s: %s timeout\n", dev->name, msg);
+done:
+	return (i >= 0) ? i : -EAGAIN;
+}
+
+static int dscc4_do_action(struct net_device *dev, char *msg)
+{
+	void __iomem *ioaddr = dscc4_priv(dev)->base_addr;
+	s16 i = 0;
+
+	writel(Action, ioaddr + GCMDR);
+	ioaddr += GSTAR;
+	do {
+		u32 state = readl(ioaddr);
+
+		if (state & ArAck) {
+			printk(KERN_DEBUG "%s: %s ack\n", dev->name, msg);
+			writel(ArAck, ioaddr);
+			goto done;
+		} else if (state & Arf) {
+			printk(KERN_ERR "%s: %s failed\n", dev->name, msg);
+			writel(Arf, ioaddr);
+			i = -1;
+			goto done;
+	}
+		rmb();
+	} while (++i > 0);
+	printk(KERN_ERR "%s: %s timeout\n", dev->name, msg);
+done:
+	return i;
+}
+
+static inline int dscc4_xpr_ack(struct dscc4_dev_priv *dpriv)
+{
+	int cur = dpriv->iqtx_current%IRQ_RING_SIZE;
+	s8 i = 0;
+
+	do {
+		if (!(dpriv->flags & (NeedIDR | NeedIDT)) ||
+		    (dpriv->iqtx[cur] & Xpr))
+			break;
+		smp_rmb();
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule_timeout(10);
+	} while (++i > 0);
+
+	return (i >= 0 ) ? i : -EAGAIN;
+}
+
+#if 0 /* dscc4_{rx/tx}_reset are both unreliable - more tweak needed */
+static void dscc4_rx_reset(struct dscc4_dev_priv *dpriv, struct net_device *dev)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&dpriv->pci_priv->lock, flags);
+	/* Cf errata DS5 p.6 */
+	writel(0x00000000, dpriv->base_addr + CH0LRDA + dpriv->dev_id*4);
+	scc_patchl(PowerUp, 0, dpriv, dev, CCR0);
+	readl(dpriv->base_addr + CH0LRDA + dpriv->dev_id*4);
+	writel(MTFi|Rdr, dpriv->base_addr + dpriv->dev_id*0x0c + CH0CFG);
+	writel(Action, dpriv->base_addr + GCMDR);
+	spin_unlock_irqrestore(&dpriv->pci_priv->lock, flags);
+}
+
+#endif
+
+#if 0
+static void dscc4_tx_reset(struct dscc4_dev_priv *dpriv, struct net_device *dev)
+{
+	u16 i = 0;
+
+	/* Cf errata DS5 p.7 */
+	scc_patchl(PowerUp, 0, dpriv, dev, CCR0);
+	scc_writel(0x00050000, dpriv, dev, CCR2);
+	/*
+	 * Must be longer than the time required to fill the fifo.
+	 */
+	while (!dscc4_tx_quiescent(dpriv, dev) && ++i) {
+		udelay(1);
+		wmb();
+	}
+
+	writel(MTFi|Rdt, dpriv->base_addr + dpriv->dev_id*0x0c + CH0CFG);
+	if (dscc4_do_action(dev, "Rdt") < 0)
+		printk(KERN_ERR "%s: Tx reset failed\n", dev->name);
+}
+#endif
+
+/* TODO: (ab)use this function to refill a completely depleted RX ring. */
+static inline void dscc4_rx_skb(struct dscc4_dev_priv *dpriv,
+				struct net_device *dev)
+{
+	struct RxFD *rx_fd = dpriv->rx_fd + dpriv->rx_current%RX_RING_SIZE;
+	struct net_device_stats *stats = hdlc_stats(dev);
+	struct pci_dev *pdev = dpriv->pci_priv->pdev;
+	struct sk_buff *skb;
+	int pkt_len;
+
+	skb = dpriv->rx_skbuff[dpriv->rx_current++%RX_RING_SIZE];
+	if (!skb) {
+		printk(KERN_DEBUG "%s: skb=0 (%s)\n", dev->name, __FUNCTION__);
+		goto refill;
+	}
+	pkt_len = TO_SIZE(rx_fd->state2);
+	pci_unmap_single(pdev, rx_fd->data, RX_MAX(HDLC_MAX_MRU), PCI_DMA_FROMDEVICE);
+	if ((skb->data[--pkt_len] & FrameOk) == FrameOk) {
+		stats->rx_packets++;
+		stats->rx_bytes += pkt_len;
+		skb_put(skb, pkt_len);
+		if (netif_running(dev))
+			skb->protocol = hdlc_type_trans(skb, dev);
+		skb->dev->last_rx = jiffies;
+		netif_rx(skb);
+	} else {
+		if (skb->data[pkt_len] & FrameRdo)
+			stats->rx_fifo_errors++;
+		else if (!(skb->data[pkt_len] | ~FrameCrc))
+			stats->rx_crc_errors++;
+		else if (!(skb->data[pkt_len] | ~(FrameVfr | FrameRab)))
+			stats->rx_length_errors++;
+		else
+			stats->rx_errors++;
+		dev_kfree_skb_irq(skb);
+	}
+refill:
+	while ((dpriv->rx_dirty - dpriv->rx_current) % RX_RING_SIZE) {
+		if (try_get_rx_skb(dpriv, dev) < 0)
+			break;
+		dpriv->rx_dirty++;
+	}
+	dscc4_rx_update(dpriv, dev);
+	rx_fd->state2 = 0x00000000;
+	rx_fd->end = 0xbabeface;
+}
+
+static void dscc4_free1(struct pci_dev *pdev)
+{
+	struct dscc4_pci_priv *ppriv;
+	struct dscc4_dev_priv *root;
+	int i;
+
+	ppriv = pci_get_drvdata(pdev);
+	root = ppriv->root;
+
+	for (i = 0; i < dev_per_card; i++)
+		unregister_hdlc_device(dscc4_to_dev(root + i));
+
+	pci_set_drvdata(pdev, NULL);
+
+	for (i = 0; i < dev_per_card; i++)
+		free_netdev(root[i].dev);
+	kfree(root);
+	kfree(ppriv);
+}
+
+static int __devinit dscc4_init_one(struct pci_dev *pdev,
+				  const struct pci_device_id *ent)
+{
+	struct dscc4_pci_priv *priv;
+	struct dscc4_dev_priv *dpriv;
+	void __iomem *ioaddr;
+	int i, rc;
+
+	printk(KERN_DEBUG "%s", version);
+
+	rc = pci_enable_device(pdev);
+	if (rc < 0)
+		goto out;
+
+	rc = pci_request_region(pdev, 0, "registers");
+	if (rc < 0) {
+	        printk(KERN_ERR "%s: can't reserve MMIO region (regs)\n",
+			DRV_NAME);
+	        goto err_disable_0;
+	}
+	rc = pci_request_region(pdev, 1, "LBI interface");
+	if (rc < 0) {
+	        printk(KERN_ERR "%s: can't reserve MMIO region (lbi)\n",
+			DRV_NAME);
+	        goto err_free_mmio_region_1;
+	}
+
+	ioaddr = ioremap(pci_resource_start(pdev, 0),
+					pci_resource_len(pdev, 0));
+	if (!ioaddr) {
+		printk(KERN_ERR "%s: cannot remap MMIO region %lx @ %lx\n",
+			DRV_NAME, pci_resource_len(pdev, 0),
+			pci_resource_start(pdev, 0));
+		rc = -EIO;
+		goto err_free_mmio_regions_2;
+	}
+	printk(KERN_DEBUG "Siemens DSCC4, MMIO at %#lx (regs), %#lx (lbi), IRQ %d\n",
+	        pci_resource_start(pdev, 0),
+	        pci_resource_start(pdev, 1), pdev->irq);
+
+	/* Cf errata DS5 p.2 */
+	pci_write_config_byte(pdev, PCI_LATENCY_TIMER, 0xf8);
+	pci_set_master(pdev);
+
+	rc = dscc4_found1(pdev, ioaddr);
+	if (rc < 0)
+	        goto err_iounmap_3;
+
+	priv = pci_get_drvdata(pdev);
+
+	rc = request_irq(pdev->irq, dscc4_irq, SA_SHIRQ, DRV_NAME, priv->root);
+	if (rc < 0) {
+		printk(KERN_WARNING "%s: IRQ %d busy\n", DRV_NAME, pdev->irq);
+		goto err_release_4;
+	}
+
+	/* power up/little endian/dma core controlled via lrda/ltda */
+	writel(0x00000001, ioaddr + GMODE);
+	/* Shared interrupt queue */
+	{
+		u32 bits;
+
+		bits = (IRQ_RING_SIZE >> 5) - 1;
+		bits |= bits << 4;
+		bits |= bits << 8;
+		bits |= bits << 16;
+		writel(bits, ioaddr + IQLENR0);
+	}
+	/* Global interrupt queue */
+	writel((u32)(((IRQ_RING_SIZE >> 5) - 1) << 20), ioaddr + IQLENR1);
+	priv->iqcfg = (u32 *) pci_alloc_consistent(pdev,
+		IRQ_RING_SIZE*sizeof(u32), &priv->iqcfg_dma);
+	if (!priv->iqcfg)
+		goto err_free_irq_5;
+	writel(priv->iqcfg_dma, ioaddr + IQCFG);
+
+	rc = -ENOMEM;
+
+	/*
+	 * SCC 0-3 private rx/tx irq structures
+	 * IQRX/TXi needs to be set soon. Learned it the hard way...
+	 */
+	for (i = 0; i < dev_per_card; i++) {
+		dpriv = priv->root + i;
+		dpriv->iqtx = (u32 *) pci_alloc_consistent(pdev,
+			IRQ_RING_SIZE*sizeof(u32), &dpriv->iqtx_dma);
+		if (!dpriv->iqtx)
+			goto err_free_iqtx_6;
+		writel(dpriv->iqtx_dma, ioaddr + IQTX0 + i*4);
+	}
+	for (i = 0; i < dev_per_card; i++) {
+		dpriv = priv->root + i;
+		dpriv->iqrx = (u32 *) pci_alloc_consistent(pdev,
+			IRQ_RING_SIZE*sizeof(u32), &dpriv->iqrx_dma);
+		if (!dpriv->iqrx)
+			goto err_free_iqrx_7;
+		writel(dpriv->iqrx_dma, ioaddr + IQRX0 + i*4);
+	}
+
+	/* Cf application hint. Beware of hard-lock condition on threshold. */
+	writel(0x42104000, ioaddr + FIFOCR1);
+	//writel(0x9ce69800, ioaddr + FIFOCR2);
+	writel(0xdef6d800, ioaddr + FIFOCR2);
+	//writel(0x11111111, ioaddr + FIFOCR4);
+	writel(0x18181818, ioaddr + FIFOCR4);
+	// FIXME: should depend on the chipset revision
+	writel(0x0000000e, ioaddr + FIFOCR3);
+
+	writel(0xff200001, ioaddr + GCMDR);
+
+	rc = 0;
+out:
+	return rc;
+
+err_free_iqrx_7:
+	while (--i >= 0) {
+		dpriv = priv->root + i;
+		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
+				    dpriv->iqrx, dpriv->iqrx_dma);
+	}
+	i = dev_per_card;
+err_free_iqtx_6:
+	while (--i >= 0) {
+		dpriv = priv->root + i;
+		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
+				    dpriv->iqtx, dpriv->iqtx_dma);
+	}
+	pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32), priv->iqcfg,
+			    priv->iqcfg_dma);
+err_free_irq_5:
+	free_irq(pdev->irq, priv->root);
+err_release_4:
+	dscc4_free1(pdev);
+err_iounmap_3:
+	iounmap (ioaddr);
+err_free_mmio_regions_2:
+	pci_release_region(pdev, 1);
+err_free_mmio_region_1:
+	pci_release_region(pdev, 0);
+err_disable_0:
+	pci_disable_device(pdev);
+	goto out;
+};
+
+/*
+ * Let's hope the default values are decent enough to protect my
+ * feet from the user's gun - Ueimor
+ */
+static void dscc4_init_registers(struct dscc4_dev_priv *dpriv,
+				 struct net_device *dev)
+{
+	/* No interrupts, SCC core disabled. Let's relax */
+	scc_writel(0x00000000, dpriv, dev, CCR0);
+
+	scc_writel(LengthCheck | (HDLC_MAX_MRU >> 5), dpriv, dev, RLCR);
+
+	/*
+	 * No address recognition/crc-CCITT/cts enabled
+	 * Shared flags transmission disabled - cf errata DS5 p.11
+	 * Carrier detect disabled - cf errata p.14
+	 * FIXME: carrier detection/polarity may be handled more gracefully.
+	 */
+	scc_writel(0x02408000, dpriv, dev, CCR1);
+
+	/* crc not forwarded - Cf errata DS5 p.11 */
+	scc_writel(0x00050008 & ~RxActivate, dpriv, dev, CCR2);
+	// crc forwarded
+	//scc_writel(0x00250008 & ~RxActivate, dpriv, dev, CCR2);
+}
+
+static inline int dscc4_set_quartz(struct dscc4_dev_priv *dpriv, int hz)
+{
+	int ret = 0;
+
+	if ((hz < 0) || (hz > DSCC4_HZ_MAX))
+		ret = -EOPNOTSUPP;
+	else
+		dpriv->pci_priv->xtal_hz = hz;
+
+	return ret;
+}
+
+static int dscc4_found1(struct pci_dev *pdev, void __iomem *ioaddr)
+{
+	struct dscc4_pci_priv *ppriv;
+	struct dscc4_dev_priv *root;
+	int i, ret = -ENOMEM;
+
+	root = kmalloc(dev_per_card*sizeof(*root), GFP_KERNEL);
+	if (!root) {
+		printk(KERN_ERR "%s: can't allocate data\n", DRV_NAME);
+		goto err_out;
+	}
+	memset(root, 0, dev_per_card*sizeof(*root));
+
+	for (i = 0; i < dev_per_card; i++) {
+		root[i].dev = alloc_hdlcdev(root + i);
+		if (!root[i].dev)
+			goto err_free_dev;
+	}
+
+	ppriv = kmalloc(sizeof(*ppriv), GFP_KERNEL);
+	if (!ppriv) {
+		printk(KERN_ERR "%s: can't allocate private data\n", DRV_NAME);
+		goto err_free_dev;
+	}
+	memset(ppriv, 0, sizeof(struct dscc4_pci_priv));
+
+	ppriv->root = root;
+	spin_lock_init(&ppriv->lock);
+
+	for (i = 0; i < dev_per_card; i++) {
+		struct dscc4_dev_priv *dpriv = root + i;
+		struct net_device *d = dscc4_to_dev(dpriv);
+		hdlc_device *hdlc = dev_to_hdlc(d);
+
+	        d->base_addr = (unsigned long)ioaddr;
+		d->init = NULL;
+	        d->irq = pdev->irq;
+	        d->open = dscc4_open;
+	        d->stop = dscc4_close;
+		d->set_multicast_list = NULL;
+	        d->do_ioctl = dscc4_ioctl;
+		d->tx_timeout = dscc4_tx_timeout;
+		d->watchdog_timeo = TX_TIMEOUT;
+		SET_MODULE_OWNER(d);
+		SET_NETDEV_DEV(d, &pdev->dev);
+
+		dpriv->dev_id = i;
+		dpriv->pci_priv = ppriv;
+		dpriv->base_addr = ioaddr;
+		spin_lock_init(&dpriv->lock);
+
+		hdlc->xmit = dscc4_start_xmit;
+		hdlc->attach = dscc4_hdlc_attach;
+
+		dscc4_init_registers(dpriv, d);
+		dpriv->parity = PARITY_CRC16_PR0_CCITT;
+		dpriv->encoding = ENCODING_NRZ;
+	
+		ret = dscc4_init_ring(d);
+		if (ret < 0)
+			goto err_unregister;
+
+		ret = register_hdlc_device(d);
+		if (ret < 0) {
+			printk(KERN_ERR "%s: unable to register\n", DRV_NAME);
+			dscc4_release_ring(dpriv);
+			goto err_unregister;
+	        }
+	}
+
+	ret = dscc4_set_quartz(root, quartz);
+	if (ret < 0)
+		goto err_unregister;
+
+	pci_set_drvdata(pdev, ppriv);
+	return ret;
+
+err_unregister:
+	while (i-- > 0) {
+		dscc4_release_ring(root + i);
+		unregister_hdlc_device(dscc4_to_dev(root + i));
+	}
+	kfree(ppriv);
+	i = dev_per_card;
+err_free_dev:
+	while (i-- > 0)
+		free_netdev(root[i].dev);
+	kfree(root);
+err_out:
+	return ret;
+};
+
+/* FIXME: get rid of the unneeded code */
+static void dscc4_timer(unsigned long data)
+{
+	struct net_device *dev = (struct net_device *)data;
+	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
+//	struct dscc4_pci_priv *ppriv;
+
+	goto done;
+done:
+        dpriv->timer.expires = jiffies + TX_TIMEOUT;
+        add_timer(&dpriv->timer);
+}
+
+static void dscc4_tx_timeout(struct net_device *dev)
+{
+	/* FIXME: something is missing there */
+}
+
+static int dscc4_loopback_check(struct dscc4_dev_priv *dpriv)
+{
+	sync_serial_settings *settings = &dpriv->settings;
+
+	if (settings->loopback && (settings->clock_type != CLOCK_INT)) {
+		struct net_device *dev = dscc4_to_dev(dpriv);
+
+		printk(KERN_INFO "%s: loopback requires clock\n", dev->name);
+		return -1;
+	}
+	return 0;
+}
+
+#ifdef CONFIG_DSCC4_PCI_RST
+/*
+ * Some DSCC4-based cards wires the GPIO port and the PCI #RST pin together
+ * so as to provide a safe way to reset the asic while not the whole machine
+ * rebooting.
+ *
+ * This code doesn't need to be efficient. Keep It Simple
+ */
+static void dscc4_pci_reset(struct pci_dev *pdev, void __iomem *ioaddr)
+{
+	int i;
+
+	down(&dscc4_sem);
+	for (i = 0; i < 16; i++)
+		pci_read_config_dword(pdev, i << 2, dscc4_pci_config_store + i);
+
+	/* Maximal LBI clock divider (who cares ?) and whole GPIO range. */
+	writel(0x001c0000, ioaddr + GMODE);
+	/* Configure GPIO port as output */
+	writel(0x0000ffff, ioaddr + GPDIR);
+	/* Disable interruption */
+	writel(0x0000ffff, ioaddr + GPIM);
+
+	writel(0x0000ffff, ioaddr + GPDATA);
+	writel(0x00000000, ioaddr + GPDATA);
+
+	/* Flush posted writes */
+	readl(ioaddr + GSTAR);
+
+	set_current_state(TASK_UNINTERRUPTIBLE);
+	schedule_timeout(10);
+
+	for (i = 0; i < 16; i++)
+		pci_write_config_dword(pdev, i << 2, dscc4_pci_config_store[i]);
+	up(&dscc4_sem);
+}
+#else
+#define dscc4_pci_reset(pdev,ioaddr)	do {} while (0)
+#endif /* CONFIG_DSCC4_PCI_RST */
+
+static int dscc4_open(struct net_device *dev)
+{
+	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
+	struct dscc4_pci_priv *ppriv;
+	int ret = -EAGAIN;
+
+	if ((dscc4_loopback_check(dpriv) < 0) || !dev->hard_start_xmit)
+		goto err;
+
+	if ((ret = hdlc_open(dev)))
+		goto err;
+
+	ppriv = dpriv->pci_priv;
+
+	/*
+	 * Due to various bugs, there is no way to reliably reset a
+	 * specific port (manufacturer's dependant special PCI #RST wiring
+	 * apart: it affects all ports). Thus the device goes in the best
+	 * silent mode possible at dscc4_close() time and simply claims to
+	 * be up if it's opened again. It still isn't possible to change
+	 * the HDLC configuration without rebooting but at least the ports
+	 * can be up/down ifconfig'ed without killing the host.
+	 */
+	if (dpriv->flags & FakeReset) {
+		dpriv->flags &= ~FakeReset;
+		scc_patchl(0, PowerUp, dpriv, dev, CCR0);
+		scc_patchl(0, 0x00050000, dpriv, dev, CCR2);
+		scc_writel(EventsMask, dpriv, dev, IMR);
+		printk(KERN_INFO "%s: up again.\n", dev->name);
+		goto done;
+	}
+
+	/* IDT+IDR during XPR */
+	dpriv->flags = NeedIDR | NeedIDT;
+
+	scc_patchl(0, PowerUp | Vis, dpriv, dev, CCR0);
+
+	/*
+	 * The following is a bit paranoid...
+	 *
+	 * NB: the datasheet "...CEC will stay active if the SCC is in
+	 * power-down mode or..." and CCR2.RAC = 1 are two different
+	 * situations.
+	 */
+	if (scc_readl_star(dpriv, dev) & SccBusy) {
+		printk(KERN_ERR "%s busy. Try later\n", dev->name);
+		ret = -EAGAIN;
+		goto err_out;
+	} else
+		printk(KERN_INFO "%s: available. Good\n", dev->name);
+
+	scc_writel(EventsMask, dpriv, dev, IMR);
+
+	/* Posted write is flushed in the wait_ack loop */
+	scc_writel(TxSccRes | RxSccRes, dpriv, dev, CMDR);
+
+	if ((ret = dscc4_wait_ack_cec(dpriv, dev, "Cec")) < 0)
+		goto err_disable_scc_events;
+
+	/*
+	 * I would expect XPR near CE completion (before ? after ?).
+	 * At worst, this code won't see a late XPR and people
+	 * will have to re-issue an ifconfig (this is harmless).
+	 * WARNING, a really missing XPR usually means a hardware
+	 * reset is needed. Suggestions anyone ?
+	 */
+	if ((ret = dscc4_xpr_ack(dpriv)) < 0) {
+		printk(KERN_ERR "%s: %s timeout\n", DRV_NAME, "XPR");
+		goto err_disable_scc_events;
+	}
+	
+	if (debug > 2)
+		dscc4_tx_print(dev, dpriv, "Open");
+
+done:
+	netif_start_queue(dev);
+
+        init_timer(&dpriv->timer);
+        dpriv->timer.expires = jiffies + 10*HZ;
+        dpriv->timer.data = (unsigned long)dev;
+        dpriv->timer.function = &dscc4_timer;
+        add_timer(&dpriv->timer);
+	netif_carrier_on(dev);
+
+	return 0;
+
+err_disable_scc_events:
+	scc_writel(0xffffffff, dpriv, dev, IMR);
+	scc_patchl(PowerUp | Vis, 0, dpriv, dev, CCR0);
+err_out:
+	hdlc_close(dev);
+err:
+	return ret;
+}
+
+#ifdef DSCC4_POLLING
+static int dscc4_tx_poll(struct dscc4_dev_priv *dpriv, struct net_device *dev)
+{
+	/* FIXME: it's gonna be easy (TM), for sure */
+}
+#endif /* DSCC4_POLLING */
+
+static int dscc4_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
+	struct dscc4_pci_priv *ppriv = dpriv->pci_priv;
+	struct TxFD *tx_fd;
+	int next;
+
+	next = dpriv->tx_current%TX_RING_SIZE;
+	dpriv->tx_skbuff[next] = skb;
+	tx_fd = dpriv->tx_fd + next;
+	tx_fd->state = FrameEnd | TO_STATE_TX(skb->len);
+	tx_fd->data = pci_map_single(ppriv->pdev, skb->data, skb->len,
+				     PCI_DMA_TODEVICE);
+	tx_fd->complete = 0x00000000;
+	tx_fd->jiffies = jiffies;
+	mb();
+
+#ifdef DSCC4_POLLING
+	spin_lock(&dpriv->lock);
+	while (dscc4_tx_poll(dpriv, dev));
+	spin_unlock(&dpriv->lock);
+#endif
+
+	dev->trans_start = jiffies;
+
+	if (debug > 2)
+		dscc4_tx_print(dev, dpriv, "Xmit");
+	/* To be cleaned(unsigned int)/optimized. Later, ok ? */
+	if (!((++dpriv->tx_current - dpriv->tx_dirty)%TX_RING_SIZE))
+		netif_stop_queue(dev);
+
+	if (dscc4_tx_quiescent(dpriv, dev))
+		dscc4_do_tx(dpriv, dev);
+
+	return 0;
+}
+
+static int dscc4_close(struct net_device *dev)
+{
+	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
+
+	del_timer_sync(&dpriv->timer);
+	netif_stop_queue(dev);
+
+	scc_patchl(PowerUp | Vis, 0, dpriv, dev, CCR0);
+	scc_patchl(0x00050000, 0, dpriv, dev, CCR2);
+	scc_writel(0xffffffff, dpriv, dev, IMR);
+
+	dpriv->flags |= FakeReset;
+
+	hdlc_close(dev);
+
+	return 0;
+}
+
+static inline int dscc4_check_clock_ability(int port)
+{
+	int ret = 0;
+
+#ifdef CONFIG_DSCC4_PCISYNC
+	if (port >= 2)
+		ret = -1;
+#endif
+	return ret;
+}
+
+/*
+ * DS1 p.137: "There are a total of 13 different clocking modes..."
+ *                                  ^^
+ * Design choices:
+ * - by default, assume a clock is provided on pin RxClk/TxClk (clock mode 0a).
+ *   Clock mode 3b _should_ work but the testing seems to make this point
+ *   dubious (DIY testing requires setting CCR0 at 0x00000033).
+ *   This is supposed to provide least surprise "DTE like" behavior.
+ * - if line rate is specified, clocks are assumed to be locally generated.
+ *   A quartz must be available (on pin XTAL1). Modes 6b/7b are used. Choosing
+ *   between these it automagically done according on the required frequency
+ *   scaling. Of course some rounding may take place.
+ * - no high speed mode (40Mb/s). May be trivial to do but I don't have an
+ *   appropriate external clocking device for testing.
+ * - no time-slot/clock mode 5: shameless lazyness.
+ *
+ * The clock signals wiring can be (is ?) manufacturer dependant. Good luck.
+ *
+ * BIG FAT WARNING: if the device isn't provided enough clocking signal, it
+ * won't pass the init sequence. For example, straight back-to-back DTE without
+ * external clock will fail when dscc4_open() (<- 'ifconfig hdlcx xxx') is
+ * called.
+ *
+ * Typos lurk in datasheet (missing divier in clock mode 7a figure 51 p.153
+ * DS0 for example)
+ *
+ * Clock mode related bits of CCR0:
+ *     +------------ TOE: output TxClk (0b/2b/3a/3b/6b/7a/7b only)
+ *     | +---------- SSEL: sub-mode select 0 -> a, 1 -> b
+ *     | | +-------- High Speed: say 0
+ *     | | | +-+-+-- Clock Mode: 0..7
+ *     | | | | | |
+ * -+-+-+-+-+-+-+-+
+ * x|x|5|4|3|2|1|0| lower bits
+ *
+ * Division factor of BRR: k = (N+1)x2^M (total divider = 16xk in mode 6b)
+ *            +-+-+-+------------------ M (0..15)
+ *            | | | |     +-+-+-+-+-+-- N (0..63)
+ *    0 0 0 0 | | | | 0 0 | | | | | |
+ * ...-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    f|e|d|c|b|a|9|8|7|6|5|4|3|2|1|0| lower bits
+ *
+ */
+static int dscc4_set_clock(struct net_device *dev, u32 *bps, u32 *state)
+{
+	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
+	int ret = -1;
+	u32 brr;
+
+	*state &= ~Ccr0ClockMask;
+	if (*bps) { /* Clock generated - required for DCE */
+		u32 n = 0, m = 0, divider;
+		int xtal;
+
+		xtal = dpriv->pci_priv->xtal_hz;
+		if (!xtal)
+			goto done;
+		if (dscc4_check_clock_ability(dpriv->dev_id) < 0)
+			goto done;
+		divider = xtal / *bps;
+		if (divider > BRR_DIVIDER_MAX) {
+			divider >>= 4;
+			*state |= 0x00000036; /* Clock mode 6b (BRG/16) */
+		} else
+			*state |= 0x00000037; /* Clock mode 7b (BRG) */
+		if (divider >> 22) {
+			n = 63;
+			m = 15;
+		} else if (divider) {
+			/* Extraction of the 6 highest weighted bits */
+			m = 0;
+			while (0xffffffc0 & divider) {
+				m++;
+				divider >>= 1;
+			}
+			n = divider;
+		}
+		brr = (m << 8) | n;
+		divider = n << m;
+		if (!(*state & 0x00000001)) /* ?b mode mask => clock mode 6b */
+			divider <<= 4;
+		*bps = xtal / divider;
+	} else {
+		/*
+		 * External clock - DTE
+		 * "state" already reflects Clock mode 0a (CCR0 = 0xzzzzzz00).
+		 * Nothing more to be done
+		 */
+		brr = 0;
+	}
+	scc_writel(brr, dpriv, dev, BRR);
+	ret = 0;
+done:
+	return ret;
+}
+
+static int dscc4_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+	sync_serial_settings __user *line = ifr->ifr_settings.ifs_ifsu.sync;
+	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
+	const size_t size = sizeof(dpriv->settings);
+	int ret = 0;
+
+        if (dev->flags & IFF_UP)
+                return -EBUSY;
+
+	if (cmd != SIOCWANDEV)
+		return -EOPNOTSUPP;
+
+	switch(ifr->ifr_settings.type) {
+	case IF_GET_IFACE:
+		ifr->ifr_settings.type = IF_IFACE_SYNC_SERIAL;
+		if (ifr->ifr_settings.size < size) {
+			ifr->ifr_settings.size = size; /* data size wanted */
+			return -ENOBUFS;
+		}
+		if (copy_to_user(line, &dpriv->settings, size))
+			return -EFAULT;
+		break;
+
+	case IF_IFACE_SYNC_SERIAL:
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+
+		if (dpriv->flags & FakeReset) {
+			printk(KERN_INFO "%s: please reset the device"
+			       " before this command\n", dev->name);
+			return -EPERM;
+		}
+		if (copy_from_user(&dpriv->settings, line, size))
+			return -EFAULT;
+		ret = dscc4_set_iface(dpriv, dev);
+		break;
+
+	default:
+		ret = hdlc_ioctl(dev, ifr, cmd);
+		break;
+	}
+
+	return ret;
+}
+
+static int dscc4_match(struct thingie *p, int value)
+{
+	int i;
+
+	for (i = 0; p[i].define != -1; i++) {
+		if (value == p[i].define)
+			break;
+	}
+	if (p[i].define == -1)
+		return -1;
+	else
+		return i;
+}
+
+static int dscc4_clock_setting(struct dscc4_dev_priv *dpriv,
+			       struct net_device *dev)
+{
+	sync_serial_settings *settings = &dpriv->settings;
+	int ret = -EOPNOTSUPP;
+	u32 bps, state;
+
+	bps = settings->clock_rate;
+	state = scc_readl(dpriv, CCR0);
+	if (dscc4_set_clock(dev, &bps, &state) < 0)
+		goto done;
+	if (bps) { /* DCE */
+		printk(KERN_DEBUG "%s: generated RxClk (DCE)\n", dev->name);
+		if (settings->clock_rate != bps) {
+			printk(KERN_DEBUG "%s: clock adjusted (%08d -> %08d)\n",
+				dev->name, settings->clock_rate, bps);
+			settings->clock_rate = bps;
+		}
+	} else { /* DTE */
+		state |= PowerUp | Vis;
+		printk(KERN_DEBUG "%s: external RxClk (DTE)\n", dev->name);
+	}
+	scc_writel(state, dpriv, dev, CCR0);
+	ret = 0;
+done:
+	return ret;
+}
+
+static int dscc4_encoding_setting(struct dscc4_dev_priv *dpriv,
+				  struct net_device *dev)
+{
+	struct thingie encoding[] = {
+		{ ENCODING_NRZ,		0x00000000 },
+		{ ENCODING_NRZI,	0x00200000 },
+		{ ENCODING_FM_MARK,	0x00400000 },
+		{ ENCODING_FM_SPACE,	0x00500000 },
+		{ ENCODING_MANCHESTER,	0x00600000 },
+		{ -1,			0}
+	};
+	int i, ret = 0;
+
+	i = dscc4_match(encoding, dpriv->encoding);
+	if (i >= 0)
+		scc_patchl(EncodingMask, encoding[i].bits, dpriv, dev, CCR0);
+	else
+		ret = -EOPNOTSUPP;
+	return ret;
+}
+
+static int dscc4_loopback_setting(struct dscc4_dev_priv *dpriv,
+				  struct net_device *dev)
+{
+	sync_serial_settings *settings = &dpriv->settings;
+	u32 state;
+
+	state = scc_readl(dpriv, CCR1);
+	if (settings->loopback) {
+		printk(KERN_DEBUG "%s: loopback\n", dev->name);
+		state |= 0x00000100;
+	} else {
+		printk(KERN_DEBUG "%s: normal\n", dev->name);
+		state &= ~0x00000100;
+	}
+	scc_writel(state, dpriv, dev, CCR1);
+	return 0;
+}
+
+static int dscc4_crc_setting(struct dscc4_dev_priv *dpriv,
+			     struct net_device *dev)
+{
+	struct thingie crc[] = {
+		{ PARITY_CRC16_PR0_CCITT,	0x00000010 },
+		{ PARITY_CRC16_PR1_CCITT,	0x00000000 },
+		{ PARITY_CRC32_PR0_CCITT,	0x00000011 },
+		{ PARITY_CRC32_PR1_CCITT,	0x00000001 }
+	};
+	int i, ret = 0;
+
+	i = dscc4_match(crc, dpriv->parity);
+	if (i >= 0)
+		scc_patchl(CrcMask, crc[i].bits, dpriv, dev, CCR1);
+	else
+		ret = -EOPNOTSUPP;
+	return ret;
+}
+
+static int dscc4_set_iface(struct dscc4_dev_priv *dpriv, struct net_device *dev)
+{
+	struct {
+		int (*action)(struct dscc4_dev_priv *, struct net_device *);
+	} *p, do_setting[] = {
+		{ dscc4_encoding_setting },
+		{ dscc4_clock_setting },
+		{ dscc4_loopback_setting },
+		{ dscc4_crc_setting },
+		{ NULL }
+	};
+	int ret = 0;
+
+	for (p = do_setting; p->action; p++) {
+		if ((ret = p->action(dpriv, dev)) < 0)
+			break;
+	}
+	return ret;
+}
+
+static irqreturn_t dscc4_irq(int irq, void *token, struct pt_regs *ptregs)
+{
+	struct dscc4_dev_priv *root = token;
+	struct dscc4_pci_priv *priv;
+	struct net_device *dev;
+	void __iomem *ioaddr;
+	u32 state;
+	unsigned long flags;
+	int i, handled = 1;
+
+	priv = root->pci_priv;
+	dev = dscc4_to_dev(root);
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	ioaddr = root->base_addr;
+
+	state = readl(ioaddr + GSTAR);
+	if (!state) {
+		handled = 0;
+		goto out;
+	}
+	if (debug > 3)
+		printk(KERN_DEBUG "%s: GSTAR = 0x%08x\n", DRV_NAME, state);
+	writel(state, ioaddr + GSTAR);
+
+	if (state & Arf) {
+		printk(KERN_ERR "%s: failure (Arf). Harass the maintener\n",
+		       dev->name);
+		goto out;
+	}
+	state &= ~ArAck;
+	if (state & Cfg) {
+		if (debug > 0)
+			printk(KERN_DEBUG "%s: CfgIV\n", DRV_NAME);
+		if (priv->iqcfg[priv->cfg_cur++%IRQ_RING_SIZE] & Arf)
+			printk(KERN_ERR "%s: %s failed\n", dev->name, "CFG");
+		if (!(state &= ~Cfg))
+			goto out;
+	}
+	if (state & RxEvt) {
+		i = dev_per_card - 1;
+		do {
+			dscc4_rx_irq(priv, root + i);
+		} while (--i >= 0);
+		state &= ~RxEvt;
+	}
+	if (state & TxEvt) {
+		i = dev_per_card - 1;
+		do {
+			dscc4_tx_irq(priv, root + i);
+		} while (--i >= 0);
+		state &= ~TxEvt;
+	}
+out:
+	spin_unlock_irqrestore(&priv->lock, flags);
+	return IRQ_RETVAL(handled);
+}
+
+static void dscc4_tx_irq(struct dscc4_pci_priv *ppriv,
+				struct dscc4_dev_priv *dpriv)
+{
+	struct net_device *dev = dscc4_to_dev(dpriv);
+	u32 state;
+	int cur, loop = 0;
+
+try:
+	cur = dpriv->iqtx_current%IRQ_RING_SIZE;
+	state = dpriv->iqtx[cur];
+	if (!state) {
+		if (debug > 4)
+			printk(KERN_DEBUG "%s: Tx ISR = 0x%08x\n", dev->name,
+			       state);
+		if ((debug > 1) && (loop > 1))
+			printk(KERN_DEBUG "%s: Tx irq loop=%d\n", dev->name, loop);
+		if (loop && netif_queue_stopped(dev))
+			if ((dpriv->tx_current - dpriv->tx_dirty)%TX_RING_SIZE)
+				netif_wake_queue(dev);
+
+		if (netif_running(dev) && dscc4_tx_quiescent(dpriv, dev) &&
+		    !dscc4_tx_done(dpriv))
+				dscc4_do_tx(dpriv, dev);
+		return;
+	}
+	loop++;
+	dpriv->iqtx[cur] = 0;
+	dpriv->iqtx_current++;
+
+	if (state_check(state, dpriv, dev, "Tx") < 0)
+		return;
+
+	if (state & SccEvt) {
+		if (state & Alls) {
+			struct net_device_stats *stats = hdlc_stats(dev);
+			struct sk_buff *skb;
+			struct TxFD *tx_fd;
+
+			if (debug > 2)
+				dscc4_tx_print(dev, dpriv, "Alls");
+			/*
+			 * DataComplete can't be trusted for Tx completion.
+			 * Cf errata DS5 p.8
+			 */
+			cur = dpriv->tx_dirty%TX_RING_SIZE;
+			tx_fd = dpriv->tx_fd + cur;
+			skb = dpriv->tx_skbuff[cur];
+			if (skb) {
+				pci_unmap_single(ppriv->pdev, tx_fd->data,
+						 skb->len, PCI_DMA_TODEVICE);
+				if (tx_fd->state & FrameEnd) {
+					stats->tx_packets++;
+					stats->tx_bytes += skb->len;
+				}
+				dev_kfree_skb_irq(skb);
+				dpriv->tx_skbuff[cur] = NULL;
+				++dpriv->tx_dirty;
+			} else {
+				if (debug > 1)
+					printk(KERN_ERR "%s Tx: NULL skb %d\n",
+						dev->name, cur);
+			}
+			/*
+			 * If the driver ends sending crap on the wire, it
+			 * will be way easier to diagnose than the (not so)
+			 * random freeze induced by null sized tx frames.
+			 */
+			tx_fd->data = tx_fd->next;
+			tx_fd->state = FrameEnd | TO_STATE_TX(2*DUMMY_SKB_SIZE);
+			tx_fd->complete = 0x00000000;
+			tx_fd->jiffies = 0;
+
+			if (!(state &= ~Alls))
+				goto try;
+		}
+		/*
+		 * Transmit Data Underrun
+		 */
+		if (state & Xdu) {
+			printk(KERN_ERR "%s: XDU. Ask maintainer\n", DRV_NAME);
+			dpriv->flags = NeedIDT;
+			/* Tx reset */
+			writel(MTFi | Rdt,
+			       dpriv->base_addr + 0x0c*dpriv->dev_id + CH0CFG);
+			writel(Action, dpriv->base_addr + GCMDR);
+			return;
+		}
+		if (state & Cts) {
+			printk(KERN_INFO "%s: CTS transition\n", dev->name);
+			if (!(state &= ~Cts)) /* DEBUG */
+				goto try;
+		}
+		if (state & Xmr) {
+			/* Frame needs to be sent again - FIXME */
+			printk(KERN_ERR "%s: Xmr. Ask maintainer\n", DRV_NAME);
+			if (!(state &= ~Xmr)) /* DEBUG */
+				goto try;
+		}
+		if (state & Xpr) {
+			void __iomem *scc_addr;
+			unsigned long ring;
+			int i;
+
+			/*
+			 * - the busy condition happens (sometimes);
+			 * - it doesn't seem to make the handler unreliable.
+			 */
+			for (i = 1; i; i <<= 1) {
+				if (!(scc_readl_star(dpriv, dev) & SccBusy))
+					break;
+			}
+			if (!i)
+				printk(KERN_INFO "%s busy in irq\n", dev->name);
+
+			scc_addr = dpriv->base_addr + 0x0c*dpriv->dev_id;
+			/* Keep this order: IDT before IDR */
+			if (dpriv->flags & NeedIDT) {
+				if (debug > 2)
+					dscc4_tx_print(dev, dpriv, "Xpr");
+				ring = dpriv->tx_fd_dma +
+				       (dpriv->tx_dirty%TX_RING_SIZE)*
+				       sizeof(struct TxFD);
+				writel(ring, scc_addr + CH0BTDA);
+				dscc4_do_tx(dpriv, dev);
+				writel(MTFi | Idt, scc_addr + CH0CFG);
+				if (dscc4_do_action(dev, "IDT") < 0)
+					goto err_xpr;
+				dpriv->flags &= ~NeedIDT;
+			}
+			if (dpriv->flags & NeedIDR) {
+				ring = dpriv->rx_fd_dma +
+				       (dpriv->rx_current%RX_RING_SIZE)*
+				       sizeof(struct RxFD);
+				writel(ring, scc_addr + CH0BRDA);
+				dscc4_rx_update(dpriv, dev);
+				writel(MTFi | Idr, scc_addr + CH0CFG);
+				if (dscc4_do_action(dev, "IDR") < 0)
+					goto err_xpr;
+				dpriv->flags &= ~NeedIDR;
+				smp_wmb();
+				/* Activate receiver and misc */
+				scc_writel(0x08050008, dpriv, dev, CCR2);
+			}
+		err_xpr:
+			if (!(state &= ~Xpr))
+				goto try;
+		}
+		if (state & Cd) {
+			if (debug > 0)
+				printk(KERN_INFO "%s: CD transition\n", dev->name);
+			if (!(state &= ~Cd)) /* DEBUG */
+				goto try;
+		}
+	} else { /* ! SccEvt */
+		if (state & Hi) {
+#ifdef DSCC4_POLLING
+			while (!dscc4_tx_poll(dpriv, dev));
+#endif
+			printk(KERN_INFO "%s: Tx Hi\n", dev->name);
+			state &= ~Hi;
+		}
+		if (state & Err) {
+			printk(KERN_INFO "%s: Tx ERR\n", dev->name);
+			hdlc_stats(dev)->tx_errors++;
+			state &= ~Err;
+		}
+	}
+	goto try;
+}
+
+static void dscc4_rx_irq(struct dscc4_pci_priv *priv,
+				    struct dscc4_dev_priv *dpriv)
+{
+	struct net_device *dev = dscc4_to_dev(dpriv);
+	u32 state;
+	int cur;
+
+try:
+	cur = dpriv->iqrx_current%IRQ_RING_SIZE;
+	state = dpriv->iqrx[cur];
+	if (!state)
+		return;
+	dpriv->iqrx[cur] = 0;
+	dpriv->iqrx_current++;
+
+	if (state_check(state, dpriv, dev, "Rx") < 0)
+		return;
+
+	if (!(state & SccEvt)){
+		struct RxFD *rx_fd;
+
+		if (debug > 4)
+			printk(KERN_DEBUG "%s: Rx ISR = 0x%08x\n", dev->name,
+			       state);
+		state &= 0x00ffffff;
+		if (state & Err) { /* Hold or reset */
+			printk(KERN_DEBUG "%s: Rx ERR\n", dev->name);
+			cur = dpriv->rx_current%RX_RING_SIZE;
+			rx_fd = dpriv->rx_fd + cur;
+			/*
+			 * Presume we're not facing a DMAC receiver reset.
+			 * As We use the rx size-filtering feature of the
+			 * DSCC4, the beginning of a new frame is waiting in
+			 * the rx fifo. I bet a Receive Data Overflow will
+			 * happen most of time but let's try and avoid it.
+			 * Btw (as for RDO) if one experiences ERR whereas
+			 * the system looks rather idle, there may be a
+			 * problem with latency. In this case, increasing
+			 * RX_RING_SIZE may help.
+			 */
+			//while (dpriv->rx_needs_refill) {
+				while (!(rx_fd->state1 & Hold)) {
+					rx_fd++;
+					cur++;
+					if (!(cur = cur%RX_RING_SIZE))
+						rx_fd = dpriv->rx_fd;
+				}
+				//dpriv->rx_needs_refill--;
+				try_get_rx_skb(dpriv, dev);
+				if (!rx_fd->data)
+					goto try;
+				rx_fd->state1 &= ~Hold;
+				rx_fd->state2 = 0x00000000;
+				rx_fd->end = 0xbabeface;
+			//}
+			goto try;
+		}
+		if (state & Fi) {
+			dscc4_rx_skb(dpriv, dev);
+			goto try;
+		}
+		if (state & Hi ) { /* HI bit */
+			printk(KERN_INFO "%s: Rx Hi\n", dev->name);
+			state &= ~Hi;
+			goto try;
+		}
+	} else { /* SccEvt */
+		if (debug > 1) {
+			//FIXME: verifier la presence de tous les evenements
+		static struct {
+			u32 mask;
+			const char *irq_name;
+		} evts[] = {
+			{ 0x00008000, "TIN"},
+			{ 0x00000020, "RSC"},
+			{ 0x00000010, "PCE"},
+			{ 0x00000008, "PLLA"},
+			{ 0, NULL}
+		}, *evt;
+
+		for (evt = evts; evt->irq_name; evt++) {
+			if (state & evt->mask) {
+					printk(KERN_DEBUG "%s: %s\n",
+						dev->name, evt->irq_name);
+				if (!(state &= ~evt->mask))
+					goto try;
+			}
+		}
+		} else {
+			if (!(state &= ~0x0000c03c))
+				goto try;
+		}
+		if (state & Cts) {
+			printk(KERN_INFO "%s: CTS transition\n", dev->name);
+			if (!(state &= ~Cts)) /* DEBUG */
+				goto try;
+		}
+		/*
+		 * Receive Data Overflow (FIXME: fscked)
+		 */
+		if (state & Rdo) {
+			struct RxFD *rx_fd;
+			void __iomem *scc_addr;
+			int cur;
+
+			//if (debug)
+			//	dscc4_rx_dump(dpriv);
+			scc_addr = dpriv->base_addr + 0x0c*dpriv->dev_id;
+
+			scc_patchl(RxActivate, 0, dpriv, dev, CCR2);
+			/*
+			 * This has no effect. Why ?
+			 * ORed with TxSccRes, one sees the CFG ack (for
+			 * the TX part only).
+			 */
+			scc_writel(RxSccRes, dpriv, dev, CMDR);
+			dpriv->flags |= RdoSet;
+
+			/*
+			 * Let's try and save something in the received data.
+			 * rx_current must be incremented at least once to
+			 * avoid HOLD in the BRDA-to-be-pointed desc.
+			 */
+			do {
+				cur = dpriv->rx_current++%RX_RING_SIZE;
+				rx_fd = dpriv->rx_fd + cur;
+				if (!(rx_fd->state2 & DataComplete))
+					break;
+				if (rx_fd->state2 & FrameAborted) {
+					hdlc_stats(dev)->rx_over_errors++;
+					rx_fd->state1 |= Hold;
+					rx_fd->state2 = 0x00000000;
+					rx_fd->end = 0xbabeface;
+				} else
+					dscc4_rx_skb(dpriv, dev);
+			} while (1);
+
+			if (debug > 0) {
+				if (dpriv->flags & RdoSet)
+					printk(KERN_DEBUG
+					       "%s: no RDO in Rx data\n", DRV_NAME);
+			}
+#ifdef DSCC4_RDO_EXPERIMENTAL_RECOVERY
+			/*
+			 * FIXME: must the reset be this violent ?
+			 */
+#warning "FIXME: CH0BRDA"
+			writel(dpriv->rx_fd_dma +
+			       (dpriv->rx_current%RX_RING_SIZE)*
+			       sizeof(struct RxFD), scc_addr + CH0BRDA);
+			writel(MTFi|Rdr|Idr, scc_addr + CH0CFG);
+			if (dscc4_do_action(dev, "RDR") < 0) {
+				printk(KERN_ERR "%s: RDO recovery failed(%s)\n",
+				       dev->name, "RDR");
+				goto rdo_end;
+			}
+			writel(MTFi|Idr, scc_addr + CH0CFG);
+			if (dscc4_do_action(dev, "IDR") < 0) {
+				printk(KERN_ERR "%s: RDO recovery failed(%s)\n",
+				       dev->name, "IDR");
+				goto rdo_end;
+			}
+		rdo_end:
+#endif
+			scc_patchl(0, RxActivate, dpriv, dev, CCR2);
+			goto try;
+		}
+		if (state & Cd) {
+			printk(KERN_INFO "%s: CD transition\n", dev->name);
+			if (!(state &= ~Cd)) /* DEBUG */
+				goto try;
+		}
+		if (state & Flex) {
+			printk(KERN_DEBUG "%s: Flex. Ttttt...\n", DRV_NAME);
+			if (!(state &= ~Flex))
+				goto try;
+		}
+	}
+}
+
+/*
+ * I had expected the following to work for the first descriptor
+ * (tx_fd->state = 0xc0000000)
+ * - Hold=1 (don't try and branch to the next descripto);
+ * - No=0 (I want an empty data section, i.e. size=0);
+ * - Fe=1 (required by No=0 or we got an Err irq and must reset).
+ * It failed and locked solid. Thus the introduction of a dummy skb.
+ * Problem is acknowledged in errata sheet DS5. Joy :o/
+ */
+struct sk_buff *dscc4_init_dummy_skb(struct dscc4_dev_priv *dpriv)
+{
+	struct sk_buff *skb;
+
+	skb = dev_alloc_skb(DUMMY_SKB_SIZE);
+	if (skb) {
+		int last = dpriv->tx_dirty%TX_RING_SIZE;
+		struct TxFD *tx_fd = dpriv->tx_fd + last;
+
+		skb->len = DUMMY_SKB_SIZE;
+		memcpy(skb->data, version, strlen(version)%DUMMY_SKB_SIZE);
+		tx_fd->state = FrameEnd | TO_STATE_TX(DUMMY_SKB_SIZE);
+		tx_fd->data = pci_map_single(dpriv->pci_priv->pdev, skb->data,
+					     DUMMY_SKB_SIZE, PCI_DMA_TODEVICE);
+		dpriv->tx_skbuff[last] = skb;
+	}
+	return skb;
+}
+
+static int dscc4_init_ring(struct net_device *dev)
+{
+	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
+	struct pci_dev *pdev = dpriv->pci_priv->pdev;
+	struct TxFD *tx_fd;
+	struct RxFD *rx_fd;
+	void *ring;
+	int i;
+
+	ring = pci_alloc_consistent(pdev, RX_TOTAL_SIZE, &dpriv->rx_fd_dma);
+	if (!ring)
+		goto err_out;
+	dpriv->rx_fd = rx_fd = (struct RxFD *) ring;
+
+	ring = pci_alloc_consistent(pdev, TX_TOTAL_SIZE, &dpriv->tx_fd_dma);
+	if (!ring)
+		goto err_free_dma_rx;
+	dpriv->tx_fd = tx_fd = (struct TxFD *) ring;
+
+	memset(dpriv->tx_skbuff, 0, sizeof(struct sk_buff *)*TX_RING_SIZE);
+	dpriv->tx_dirty = 0xffffffff;
+	i = dpriv->tx_current = 0;
+	do {
+		tx_fd->state = FrameEnd | TO_STATE_TX(2*DUMMY_SKB_SIZE);
+		tx_fd->complete = 0x00000000;
+	        /* FIXME: NULL should be ok - to be tried */
+	        tx_fd->data = dpriv->tx_fd_dma;
+		(tx_fd++)->next = (u32)(dpriv->tx_fd_dma +
+					(++i%TX_RING_SIZE)*sizeof(*tx_fd));
+	} while (i < TX_RING_SIZE);
+
+	if (dscc4_init_dummy_skb(dpriv) < 0)
+		goto err_free_dma_tx;
+
+	memset(dpriv->rx_skbuff, 0, sizeof(struct sk_buff *)*RX_RING_SIZE);
+	i = dpriv->rx_dirty = dpriv->rx_current = 0;
+	do {
+		/* size set by the host. Multiple of 4 bytes please */
+	        rx_fd->state1 = HiDesc;
+	        rx_fd->state2 = 0x00000000;
+	        rx_fd->end = 0xbabeface;
+	        rx_fd->state1 |= TO_STATE_RX(HDLC_MAX_MRU);
+		// FIXME: return value verifiee mais traitement suspect
+		if (try_get_rx_skb(dpriv, dev) >= 0)
+			dpriv->rx_dirty++;
+		(rx_fd++)->next = (u32)(dpriv->rx_fd_dma +
+					(++i%RX_RING_SIZE)*sizeof(*rx_fd));
+	} while (i < RX_RING_SIZE);
+
+	return 0;
+
+err_free_dma_tx:
+	pci_free_consistent(pdev, TX_TOTAL_SIZE, ring, dpriv->tx_fd_dma);
+err_free_dma_rx:
+	pci_free_consistent(pdev, RX_TOTAL_SIZE, rx_fd, dpriv->rx_fd_dma);
+err_out:
+	return -ENOMEM;
+}
+
+static void __devexit dscc4_remove_one(struct pci_dev *pdev)
+{
+	struct dscc4_pci_priv *ppriv;
+	struct dscc4_dev_priv *root;
+	void __iomem *ioaddr;
+	int i;
+
+	ppriv = pci_get_drvdata(pdev);
+	root = ppriv->root;
+
+	ioaddr = root->base_addr;
+
+	dscc4_pci_reset(pdev, ioaddr);
+
+	free_irq(pdev->irq, root);
+	pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32), ppriv->iqcfg,
+			    ppriv->iqcfg_dma);
+	for (i = 0; i < dev_per_card; i++) {
+		struct dscc4_dev_priv *dpriv = root + i;
+
+		dscc4_release_ring(dpriv);
+		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
+				    dpriv->iqrx, dpriv->iqrx_dma);
+		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
+				    dpriv->iqtx, dpriv->iqtx_dma);
+	}
+
+	dscc4_free1(pdev);
+
+	iounmap(ioaddr);
+
+	pci_release_region(pdev, 1);
+	pci_release_region(pdev, 0);
+
+	pci_disable_device(pdev);
+}
+
+static int dscc4_hdlc_attach(struct net_device *dev, unsigned short encoding,
+	unsigned short parity)
+{
+	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
+
+	if (encoding != ENCODING_NRZ &&
+	    encoding != ENCODING_NRZI &&
+	    encoding != ENCODING_FM_MARK &&
+	    encoding != ENCODING_FM_SPACE &&
+	    encoding != ENCODING_MANCHESTER)
+		return -EINVAL;
+
+	if (parity != PARITY_NONE &&
+	    parity != PARITY_CRC16_PR0_CCITT &&
+	    parity != PARITY_CRC16_PR1_CCITT &&
+	    parity != PARITY_CRC32_PR0_CCITT &&
+	    parity != PARITY_CRC32_PR1_CCITT)
+		return -EINVAL;
+
+        dpriv->encoding = encoding;
+        dpriv->parity = parity;
+	return 0;
+}
+
+#ifndef MODULE
+static int __init dscc4_setup(char *str)
+{
+	int *args[] = { &debug, &quartz, NULL }, **p = args;
+
+	while (*p && (get_option(&str, *p) == 2))
+		p++;
+	return 1;
+}
+
+__setup("dscc4.setup=", dscc4_setup);
+#endif
+
+static struct pci_device_id dscc4_pci_tbl[] = {
+	{ PCI_VENDOR_ID_SIEMENS, PCI_DEVICE_ID_SIEMENS_DSCC4,
+	        PCI_ANY_ID, PCI_ANY_ID, },
+	{ 0,}
+};
+MODULE_DEVICE_TABLE(pci, dscc4_pci_tbl);
+
+static struct pci_driver dscc4_driver = {
+	.name		= DRV_NAME,
+	.id_table	= dscc4_pci_tbl,
+	.probe		= dscc4_init_one,
+	.remove		= __devexit_p(dscc4_remove_one),
+};
+
+static int __init dscc4_init_module(void)
+{
+	return pci_module_init(&dscc4_driver);
+}
+
+static void __exit dscc4_cleanup_module(void)
+{
+	pci_unregister_driver(&dscc4_driver);
+}
+
+module_init(dscc4_init_module);
+module_exit(dscc4_cleanup_module);