Linux Audio

Check our new training course

Loading...
Note: File does not exist in v6.8.
   1/*
   2 * drivers/net/wan/dscc4/dscc4.c: a DSCC4 HDLC driver for Linux
   3 *
   4 * This software may be used and distributed according to the terms of the
   5 * GNU General Public License.
   6 *
   7 * The author may be reached as romieu@cogenit.fr.
   8 * Specific bug reports/asian food will be welcome.
   9 *
  10 * Special thanks to the nice people at CS-Telecom for the hardware and the
  11 * access to the test/measure tools.
  12 *
  13 *
  14 *                             Theory of Operation
  15 *
  16 * I. Board Compatibility
  17 *
  18 * This device driver is designed for the Siemens PEB20534 4 ports serial
  19 * controller as found on Etinc PCISYNC cards. The documentation for the
  20 * chipset is available at http://www.infineon.com:
  21 * - Data Sheet "DSCC4, DMA Supported Serial Communication Controller with
  22 * 4 Channels, PEB 20534 Version 2.1, PEF 20534 Version 2.1";
  23 * - Application Hint "Management of DSCC4 on-chip FIFO resources".
  24 * - Errata sheet DS5 (courtesy of Michael Skerritt).
  25 * Jens David has built an adapter based on the same chipset. Take a look
  26 * at http://www.afthd.tu-darmstadt.de/~dg1kjd/pciscc4 for a specific
  27 * driver.
  28 * Sample code (2 revisions) is available at Infineon.
  29 *
  30 * II. Board-specific settings
  31 *
  32 * Pcisync can transmit some clock signal to the outside world on the
  33 * *first two* ports provided you put a quartz and a line driver on it and
  34 * remove the jumpers. The operation is described on Etinc web site. If you
  35 * go DCE on these ports, don't forget to use an adequate cable.
  36 *
  37 * Sharing of the PCI interrupt line for this board is possible.
  38 *
  39 * III. Driver operation
  40 *
  41 * The rx/tx operations are based on a linked list of descriptors. The driver
  42 * doesn't use HOLD mode any more. HOLD mode is definitely buggy and the more
  43 * I tried to fix it, the more it started to look like (convoluted) software
  44 * mutation of LxDA method. Errata sheet DS5 suggests to use LxDA: consider
  45 * this a rfc2119 MUST.
  46 *
  47 * Tx direction
  48 * When the tx ring is full, the xmit routine issues a call to netdev_stop.
  49 * The device is supposed to be enabled again during an ALLS irq (we could
  50 * use HI but as it's easy to lose events, it's fscked).
  51 *
  52 * Rx direction
  53 * The received frames aren't supposed to span over multiple receiving areas.
  54 * I may implement it some day but it isn't the highest ranked item.
  55 *
  56 * IV. Notes
  57 * The current error (XDU, RFO) recovery code is untested.
  58 * So far, RDO takes his RX channel down and the right sequence to enable it
  59 * again is still a mystery. If RDO happens, plan a reboot. More details
  60 * in the code (NB: as this happens, TX still works).
  61 * Don't mess the cables during operation, especially on DTE ports. I don't
  62 * suggest it for DCE either but at least one can get some messages instead
  63 * of a complete instant freeze.
  64 * Tests are done on Rev. 20 of the silicium. The RDO handling changes with
  65 * the documentation/chipset releases.
  66 *
  67 * TODO:
  68 * - test X25.
  69 * - use polling at high irq/s,
  70 * - performance analysis,
  71 * - endianness.
  72 *
  73 * 2001/12/10	Daniela Squassoni  <daniela@cyclades.com>
  74 * - Contribution to support the new generic HDLC layer.
  75 *
  76 * 2002/01	Ueimor
  77 * - old style interface removal
  78 * - dscc4_release_ring fix (related to DMA mapping)
  79 * - hard_start_xmit fix (hint: TxSizeMax)
  80 * - misc crapectomy.
  81 */
  82
  83#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  84
  85#include <linux/module.h>
  86#include <linux/sched.h>
  87#include <linux/types.h>
  88#include <linux/errno.h>
  89#include <linux/list.h>
  90#include <linux/ioport.h>
  91#include <linux/pci.h>
  92#include <linux/kernel.h>
  93#include <linux/mm.h>
  94#include <linux/slab.h>
  95
  96#include <asm/system.h>
  97#include <asm/cache.h>
  98#include <asm/byteorder.h>
  99#include <asm/uaccess.h>
 100#include <asm/io.h>
 101#include <asm/irq.h>
 102
 103#include <linux/init.h>
 104#include <linux/interrupt.h>
 105#include <linux/string.h>
 106
 107#include <linux/if_arp.h>
 108#include <linux/netdevice.h>
 109#include <linux/skbuff.h>
 110#include <linux/delay.h>
 111#include <linux/hdlc.h>
 112#include <linux/mutex.h>
 113
 114/* Version */
 115static const char version[] = "$Id: dscc4.c,v 1.173 2003/09/20 23:55:34 romieu Exp $ for Linux\n";
 116static int debug;
 117static int quartz;
 118
 119#ifdef CONFIG_DSCC4_PCI_RST
 120static DEFINE_MUTEX(dscc4_mutex);
 121static u32 dscc4_pci_config_store[16];
 122#endif
 123
 124#define	DRV_NAME	"dscc4"
 125
 126#undef DSCC4_POLLING
 127
 128/* Module parameters */
 129
 130MODULE_AUTHOR("Maintainer: Francois Romieu <romieu@cogenit.fr>");
 131MODULE_DESCRIPTION("Siemens PEB20534 PCI Controller");
 132MODULE_LICENSE("GPL");
 133module_param(debug, int, 0);
 134MODULE_PARM_DESC(debug,"Enable/disable extra messages");
 135module_param(quartz, int, 0);
 136MODULE_PARM_DESC(quartz,"If present, on-board quartz frequency (Hz)");
 137
 138/* Structures */
 139
 140struct thingie {
 141	int define;
 142	u32 bits;
 143};
 144
 145struct TxFD {
 146	__le32 state;
 147	__le32 next;
 148	__le32 data;
 149	__le32 complete;
 150	u32 jiffies; /* Allows sizeof(TxFD) == sizeof(RxFD) + extra hack */
 151		     /* FWIW, datasheet calls that "dummy" and says that card
 152		      * never looks at it; neither does the driver */
 153};
 154
 155struct RxFD {
 156	__le32 state1;
 157	__le32 next;
 158	__le32 data;
 159	__le32 state2;
 160	__le32 end;
 161};
 162
 163#define DUMMY_SKB_SIZE		64
 164#define TX_LOW			8
 165#define TX_RING_SIZE		32
 166#define RX_RING_SIZE		32
 167#define TX_TOTAL_SIZE		TX_RING_SIZE*sizeof(struct TxFD)
 168#define RX_TOTAL_SIZE		RX_RING_SIZE*sizeof(struct RxFD)
 169#define IRQ_RING_SIZE		64		/* Keep it a multiple of 32 */
 170#define TX_TIMEOUT		(HZ/10)
 171#define DSCC4_HZ_MAX		33000000
 172#define BRR_DIVIDER_MAX		64*0x00004000	/* Cf errata DS5 p.10 */
 173#define dev_per_card		4
 174#define SCC_REGISTERS_MAX	23		/* Cf errata DS5 p.4 */
 175
 176#define SOURCE_ID(flags)	(((flags) >> 28) & 0x03)
 177#define TO_SIZE(state)		(((state) >> 16) & 0x1fff)
 178
 179/*
 180 * Given the operating range of Linux HDLC, the 2 defines below could be
 181 * made simpler. However they are a fine reminder for the limitations of
 182 * the driver: it's better to stay < TxSizeMax and < RxSizeMax.
 183 */
 184#define TO_STATE_TX(len)	cpu_to_le32(((len) & TxSizeMax) << 16)
 185#define TO_STATE_RX(len)	cpu_to_le32((RX_MAX(len) % RxSizeMax) << 16)
 186#define RX_MAX(len)		((((len) >> 5) + 1) << 5)	/* Cf RLCR */
 187#define SCC_REG_START(dpriv)	(SCC_START+(dpriv->dev_id)*SCC_OFFSET)
 188
 189struct dscc4_pci_priv {
 190        __le32 *iqcfg;
 191        int cfg_cur;
 192        spinlock_t lock;
 193        struct pci_dev *pdev;
 194
 195        struct dscc4_dev_priv *root;
 196        dma_addr_t iqcfg_dma;
 197	u32 xtal_hz;
 198};
 199
 200struct dscc4_dev_priv {
 201        struct sk_buff *rx_skbuff[RX_RING_SIZE];
 202        struct sk_buff *tx_skbuff[TX_RING_SIZE];
 203
 204        struct RxFD *rx_fd;
 205        struct TxFD *tx_fd;
 206        __le32 *iqrx;
 207        __le32 *iqtx;
 208
 209	/* FIXME: check all the volatile are required */
 210        volatile u32 tx_current;
 211        u32 rx_current;
 212        u32 iqtx_current;
 213        u32 iqrx_current;
 214
 215        volatile u32 tx_dirty;
 216        volatile u32 ltda;
 217        u32 rx_dirty;
 218        u32 lrda;
 219
 220        dma_addr_t tx_fd_dma;
 221        dma_addr_t rx_fd_dma;
 222        dma_addr_t iqtx_dma;
 223        dma_addr_t iqrx_dma;
 224
 225	u32 scc_regs[SCC_REGISTERS_MAX]; /* Cf errata DS5 p.4 */
 226
 227	struct timer_list timer;
 228
 229        struct dscc4_pci_priv *pci_priv;
 230        spinlock_t lock;
 231
 232        int dev_id;
 233	volatile u32 flags;
 234	u32 timer_help;
 235
 236	unsigned short encoding;
 237	unsigned short parity;
 238	struct net_device *dev;
 239	sync_serial_settings settings;
 240	void __iomem *base_addr;
 241	u32 __pad __attribute__ ((aligned (4)));
 242};
 243
 244/* GLOBAL registers definitions */
 245#define GCMDR   0x00
 246#define GSTAR   0x04
 247#define GMODE   0x08
 248#define IQLENR0 0x0C
 249#define IQLENR1 0x10
 250#define IQRX0   0x14
 251#define IQTX0   0x24
 252#define IQCFG   0x3c
 253#define FIFOCR1 0x44
 254#define FIFOCR2 0x48
 255#define FIFOCR3 0x4c
 256#define FIFOCR4 0x34
 257#define CH0CFG  0x50
 258#define CH0BRDA 0x54
 259#define CH0BTDA 0x58
 260#define CH0FRDA 0x98
 261#define CH0FTDA 0xb0
 262#define CH0LRDA 0xc8
 263#define CH0LTDA 0xe0
 264
 265/* SCC registers definitions */
 266#define SCC_START	0x0100
 267#define SCC_OFFSET      0x80
 268#define CMDR    0x00
 269#define STAR    0x04
 270#define CCR0    0x08
 271#define CCR1    0x0c
 272#define CCR2    0x10
 273#define BRR     0x2C
 274#define RLCR    0x40
 275#define IMR     0x54
 276#define ISR     0x58
 277
 278#define GPDIR	0x0400
 279#define GPDATA	0x0404
 280#define GPIM	0x0408
 281
 282/* Bit masks */
 283#define EncodingMask	0x00700000
 284#define CrcMask		0x00000003
 285
 286#define IntRxScc0	0x10000000
 287#define IntTxScc0	0x01000000
 288
 289#define TxPollCmd	0x00000400
 290#define RxActivate	0x08000000
 291#define MTFi		0x04000000
 292#define Rdr		0x00400000
 293#define Rdt		0x00200000
 294#define Idr		0x00100000
 295#define Idt		0x00080000
 296#define TxSccRes	0x01000000
 297#define RxSccRes	0x00010000
 298#define TxSizeMax	0x1fff		/* Datasheet DS1 - 11.1.1.1 */
 299#define RxSizeMax	0x1ffc		/* Datasheet DS1 - 11.1.2.1 */
 300
 301#define Ccr0ClockMask	0x0000003f
 302#define Ccr1LoopMask	0x00000200
 303#define IsrMask		0x000fffff
 304#define BrrExpMask	0x00000f00
 305#define BrrMultMask	0x0000003f
 306#define EncodingMask	0x00700000
 307#define Hold		cpu_to_le32(0x40000000)
 308#define SccBusy		0x10000000
 309#define PowerUp		0x80000000
 310#define Vis		0x00001000
 311#define FrameOk		(FrameVfr | FrameCrc)
 312#define FrameVfr	0x80
 313#define FrameRdo	0x40
 314#define FrameCrc	0x20
 315#define FrameRab	0x10
 316#define FrameAborted	cpu_to_le32(0x00000200)
 317#define FrameEnd	cpu_to_le32(0x80000000)
 318#define DataComplete	cpu_to_le32(0x40000000)
 319#define LengthCheck	0x00008000
 320#define SccEvt		0x02000000
 321#define NoAck		0x00000200
 322#define Action		0x00000001
 323#define HiDesc		cpu_to_le32(0x20000000)
 324
 325/* SCC events */
 326#define RxEvt		0xf0000000
 327#define TxEvt		0x0f000000
 328#define Alls		0x00040000
 329#define Xdu		0x00010000
 330#define Cts		0x00004000
 331#define Xmr		0x00002000
 332#define Xpr		0x00001000
 333#define Rdo		0x00000080
 334#define Rfs		0x00000040
 335#define Cd		0x00000004
 336#define Rfo		0x00000002
 337#define Flex		0x00000001
 338
 339/* DMA core events */
 340#define Cfg		0x00200000
 341#define Hi		0x00040000
 342#define Fi		0x00020000
 343#define Err		0x00010000
 344#define Arf		0x00000002
 345#define ArAck		0x00000001
 346
 347/* State flags */
 348#define Ready		0x00000000
 349#define NeedIDR		0x00000001
 350#define NeedIDT		0x00000002
 351#define RdoSet		0x00000004
 352#define FakeReset	0x00000008
 353
 354/* Don't mask RDO. Ever. */
 355#ifdef DSCC4_POLLING
 356#define EventsMask	0xfffeef7f
 357#else
 358#define EventsMask	0xfffa8f7a
 359#endif
 360
 361/* Functions prototypes */
 362static void dscc4_rx_irq(struct dscc4_pci_priv *, struct dscc4_dev_priv *);
 363static void dscc4_tx_irq(struct dscc4_pci_priv *, struct dscc4_dev_priv *);
 364static int dscc4_found1(struct pci_dev *, void __iomem *ioaddr);
 365static int dscc4_init_one(struct pci_dev *, const struct pci_device_id *ent);
 366static int dscc4_open(struct net_device *);
 367static netdev_tx_t dscc4_start_xmit(struct sk_buff *,
 368					  struct net_device *);
 369static int dscc4_close(struct net_device *);
 370static int dscc4_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
 371static int dscc4_init_ring(struct net_device *);
 372static void dscc4_release_ring(struct dscc4_dev_priv *);
 373static void dscc4_timer(unsigned long);
 374static void dscc4_tx_timeout(struct net_device *);
 375static irqreturn_t dscc4_irq(int irq, void *dev_id);
 376static int dscc4_hdlc_attach(struct net_device *, unsigned short, unsigned short);
 377static int dscc4_set_iface(struct dscc4_dev_priv *, struct net_device *);
 378#ifdef DSCC4_POLLING
 379static int dscc4_tx_poll(struct dscc4_dev_priv *, struct net_device *);
 380#endif
 381
 382static inline struct dscc4_dev_priv *dscc4_priv(struct net_device *dev)
 383{
 384	return dev_to_hdlc(dev)->priv;
 385}
 386
 387static inline struct net_device *dscc4_to_dev(struct dscc4_dev_priv *p)
 388{
 389	return p->dev;
 390}
 391
 392static void scc_patchl(u32 mask, u32 value, struct dscc4_dev_priv *dpriv,
 393			struct net_device *dev, int offset)
 394{
 395	u32 state;
 396
 397	/* Cf scc_writel for concern regarding thread-safety */
 398	state = dpriv->scc_regs[offset >> 2];
 399	state &= ~mask;
 400	state |= value;
 401	dpriv->scc_regs[offset >> 2] = state;
 402	writel(state, dpriv->base_addr + SCC_REG_START(dpriv) + offset);
 403}
 404
 405static void scc_writel(u32 bits, struct dscc4_dev_priv *dpriv,
 406		       struct net_device *dev, int offset)
 407{
 408	/*
 409	 * Thread-UNsafe.
 410	 * As of 2002/02/16, there are no thread racing for access.
 411	 */
 412	dpriv->scc_regs[offset >> 2] = bits;
 413	writel(bits, dpriv->base_addr + SCC_REG_START(dpriv) + offset);
 414}
 415
 416static inline u32 scc_readl(struct dscc4_dev_priv *dpriv, int offset)
 417{
 418	return dpriv->scc_regs[offset >> 2];
 419}
 420
 421static u32 scc_readl_star(struct dscc4_dev_priv *dpriv, struct net_device *dev)
 422{
 423	/* Cf errata DS5 p.4 */
 424	readl(dpriv->base_addr + SCC_REG_START(dpriv) + STAR);
 425	return readl(dpriv->base_addr + SCC_REG_START(dpriv) + STAR);
 426}
 427
 428static inline void dscc4_do_tx(struct dscc4_dev_priv *dpriv,
 429			       struct net_device *dev)
 430{
 431	dpriv->ltda = dpriv->tx_fd_dma +
 432                      ((dpriv->tx_current-1)%TX_RING_SIZE)*sizeof(struct TxFD);
 433	writel(dpriv->ltda, dpriv->base_addr + CH0LTDA + dpriv->dev_id*4);
 434	/* Flush posted writes *NOW* */
 435	readl(dpriv->base_addr + CH0LTDA + dpriv->dev_id*4);
 436}
 437
 438static inline void dscc4_rx_update(struct dscc4_dev_priv *dpriv,
 439				   struct net_device *dev)
 440{
 441	dpriv->lrda = dpriv->rx_fd_dma +
 442		      ((dpriv->rx_dirty - 1)%RX_RING_SIZE)*sizeof(struct RxFD);
 443	writel(dpriv->lrda, dpriv->base_addr + CH0LRDA + dpriv->dev_id*4);
 444}
 445
 446static inline unsigned int dscc4_tx_done(struct dscc4_dev_priv *dpriv)
 447{
 448	return dpriv->tx_current == dpriv->tx_dirty;
 449}
 450
 451static inline unsigned int dscc4_tx_quiescent(struct dscc4_dev_priv *dpriv,
 452					      struct net_device *dev)
 453{
 454	return readl(dpriv->base_addr + CH0FTDA + dpriv->dev_id*4) == dpriv->ltda;
 455}
 456
 457static int state_check(u32 state, struct dscc4_dev_priv *dpriv,
 458		       struct net_device *dev, const char *msg)
 459{
 460	int ret = 0;
 461
 462	if (debug > 1) {
 463	if (SOURCE_ID(state) != dpriv->dev_id) {
 464		printk(KERN_DEBUG "%s (%s): Source Id=%d, state=%08x\n",
 465		       dev->name, msg, SOURCE_ID(state), state );
 466			ret = -1;
 467	}
 468	if (state & 0x0df80c00) {
 469		printk(KERN_DEBUG "%s (%s): state=%08x (UFO alert)\n",
 470		       dev->name, msg, state);
 471			ret = -1;
 472	}
 473	}
 474	return ret;
 475}
 476
 477static void dscc4_tx_print(struct net_device *dev,
 478			   struct dscc4_dev_priv *dpriv,
 479			   char *msg)
 480{
 481	printk(KERN_DEBUG "%s: tx_current=%02d tx_dirty=%02d (%s)\n",
 482	       dev->name, dpriv->tx_current, dpriv->tx_dirty, msg);
 483}
 484
 485static void dscc4_release_ring(struct dscc4_dev_priv *dpriv)
 486{
 487	struct pci_dev *pdev = dpriv->pci_priv->pdev;
 488	struct TxFD *tx_fd = dpriv->tx_fd;
 489	struct RxFD *rx_fd = dpriv->rx_fd;
 490	struct sk_buff **skbuff;
 491	int i;
 492
 493	pci_free_consistent(pdev, TX_TOTAL_SIZE, tx_fd, dpriv->tx_fd_dma);
 494	pci_free_consistent(pdev, RX_TOTAL_SIZE, rx_fd, dpriv->rx_fd_dma);
 495
 496	skbuff = dpriv->tx_skbuff;
 497	for (i = 0; i < TX_RING_SIZE; i++) {
 498		if (*skbuff) {
 499			pci_unmap_single(pdev, le32_to_cpu(tx_fd->data),
 500				(*skbuff)->len, PCI_DMA_TODEVICE);
 501			dev_kfree_skb(*skbuff);
 502		}
 503		skbuff++;
 504		tx_fd++;
 505	}
 506
 507	skbuff = dpriv->rx_skbuff;
 508	for (i = 0; i < RX_RING_SIZE; i++) {
 509		if (*skbuff) {
 510			pci_unmap_single(pdev, le32_to_cpu(rx_fd->data),
 511				RX_MAX(HDLC_MAX_MRU), PCI_DMA_FROMDEVICE);
 512			dev_kfree_skb(*skbuff);
 513		}
 514		skbuff++;
 515		rx_fd++;
 516	}
 517}
 518
 519static inline int try_get_rx_skb(struct dscc4_dev_priv *dpriv,
 520				 struct net_device *dev)
 521{
 522	unsigned int dirty = dpriv->rx_dirty%RX_RING_SIZE;
 523	struct RxFD *rx_fd = dpriv->rx_fd + dirty;
 524	const int len = RX_MAX(HDLC_MAX_MRU);
 525	struct sk_buff *skb;
 526	int ret = 0;
 527
 528	skb = dev_alloc_skb(len);
 529	dpriv->rx_skbuff[dirty] = skb;
 530	if (skb) {
 531		skb->protocol = hdlc_type_trans(skb, dev);
 532		rx_fd->data = cpu_to_le32(pci_map_single(dpriv->pci_priv->pdev,
 533					  skb->data, len, PCI_DMA_FROMDEVICE));
 534	} else {
 535		rx_fd->data = 0;
 536		ret = -1;
 537	}
 538	return ret;
 539}
 540
 541/*
 542 * IRQ/thread/whatever safe
 543 */
 544static int dscc4_wait_ack_cec(struct dscc4_dev_priv *dpriv,
 545			      struct net_device *dev, char *msg)
 546{
 547	s8 i = 0;
 548
 549	do {
 550		if (!(scc_readl_star(dpriv, dev) & SccBusy)) {
 551			printk(KERN_DEBUG "%s: %s ack (%d try)\n", dev->name,
 552			       msg, i);
 553			goto done;
 554		}
 555		schedule_timeout_uninterruptible(10);
 556		rmb();
 557	} while (++i > 0);
 558	netdev_err(dev, "%s timeout\n", msg);
 559done:
 560	return (i >= 0) ? i : -EAGAIN;
 561}
 562
 563static int dscc4_do_action(struct net_device *dev, char *msg)
 564{
 565	void __iomem *ioaddr = dscc4_priv(dev)->base_addr;
 566	s16 i = 0;
 567
 568	writel(Action, ioaddr + GCMDR);
 569	ioaddr += GSTAR;
 570	do {
 571		u32 state = readl(ioaddr);
 572
 573		if (state & ArAck) {
 574			netdev_dbg(dev, "%s ack\n", msg);
 575			writel(ArAck, ioaddr);
 576			goto done;
 577		} else if (state & Arf) {
 578			netdev_err(dev, "%s failed\n", msg);
 579			writel(Arf, ioaddr);
 580			i = -1;
 581			goto done;
 582	}
 583		rmb();
 584	} while (++i > 0);
 585	netdev_err(dev, "%s timeout\n", msg);
 586done:
 587	return i;
 588}
 589
 590static inline int dscc4_xpr_ack(struct dscc4_dev_priv *dpriv)
 591{
 592	int cur = dpriv->iqtx_current%IRQ_RING_SIZE;
 593	s8 i = 0;
 594
 595	do {
 596		if (!(dpriv->flags & (NeedIDR | NeedIDT)) ||
 597		    (dpriv->iqtx[cur] & cpu_to_le32(Xpr)))
 598			break;
 599		smp_rmb();
 600		schedule_timeout_uninterruptible(10);
 601	} while (++i > 0);
 602
 603	return (i >= 0 ) ? i : -EAGAIN;
 604}
 605
 606#if 0 /* dscc4_{rx/tx}_reset are both unreliable - more tweak needed */
 607static void dscc4_rx_reset(struct dscc4_dev_priv *dpriv, struct net_device *dev)
 608{
 609	unsigned long flags;
 610
 611	spin_lock_irqsave(&dpriv->pci_priv->lock, flags);
 612	/* Cf errata DS5 p.6 */
 613	writel(0x00000000, dpriv->base_addr + CH0LRDA + dpriv->dev_id*4);
 614	scc_patchl(PowerUp, 0, dpriv, dev, CCR0);
 615	readl(dpriv->base_addr + CH0LRDA + dpriv->dev_id*4);
 616	writel(MTFi|Rdr, dpriv->base_addr + dpriv->dev_id*0x0c + CH0CFG);
 617	writel(Action, dpriv->base_addr + GCMDR);
 618	spin_unlock_irqrestore(&dpriv->pci_priv->lock, flags);
 619}
 620
 621#endif
 622
 623#if 0
 624static void dscc4_tx_reset(struct dscc4_dev_priv *dpriv, struct net_device *dev)
 625{
 626	u16 i = 0;
 627
 628	/* Cf errata DS5 p.7 */
 629	scc_patchl(PowerUp, 0, dpriv, dev, CCR0);
 630	scc_writel(0x00050000, dpriv, dev, CCR2);
 631	/*
 632	 * Must be longer than the time required to fill the fifo.
 633	 */
 634	while (!dscc4_tx_quiescent(dpriv, dev) && ++i) {
 635		udelay(1);
 636		wmb();
 637	}
 638
 639	writel(MTFi|Rdt, dpriv->base_addr + dpriv->dev_id*0x0c + CH0CFG);
 640	if (dscc4_do_action(dev, "Rdt") < 0)
 641		netdev_err(dev, "Tx reset failed\n");
 642}
 643#endif
 644
 645/* TODO: (ab)use this function to refill a completely depleted RX ring. */
 646static inline void dscc4_rx_skb(struct dscc4_dev_priv *dpriv,
 647				struct net_device *dev)
 648{
 649	struct RxFD *rx_fd = dpriv->rx_fd + dpriv->rx_current%RX_RING_SIZE;
 650	struct pci_dev *pdev = dpriv->pci_priv->pdev;
 651	struct sk_buff *skb;
 652	int pkt_len;
 653
 654	skb = dpriv->rx_skbuff[dpriv->rx_current++%RX_RING_SIZE];
 655	if (!skb) {
 656		printk(KERN_DEBUG "%s: skb=0 (%s)\n", dev->name, __func__);
 657		goto refill;
 658	}
 659	pkt_len = TO_SIZE(le32_to_cpu(rx_fd->state2));
 660	pci_unmap_single(pdev, le32_to_cpu(rx_fd->data),
 661			 RX_MAX(HDLC_MAX_MRU), PCI_DMA_FROMDEVICE);
 662	if ((skb->data[--pkt_len] & FrameOk) == FrameOk) {
 663		dev->stats.rx_packets++;
 664		dev->stats.rx_bytes += pkt_len;
 665		skb_put(skb, pkt_len);
 666		if (netif_running(dev))
 667			skb->protocol = hdlc_type_trans(skb, dev);
 668		netif_rx(skb);
 669	} else {
 670		if (skb->data[pkt_len] & FrameRdo)
 671			dev->stats.rx_fifo_errors++;
 672		else if (!(skb->data[pkt_len] & FrameCrc))
 673			dev->stats.rx_crc_errors++;
 674		else if ((skb->data[pkt_len] & (FrameVfr | FrameRab)) !=
 675			 (FrameVfr | FrameRab))
 676			dev->stats.rx_length_errors++;
 677		dev->stats.rx_errors++;
 678		dev_kfree_skb_irq(skb);
 679	}
 680refill:
 681	while ((dpriv->rx_dirty - dpriv->rx_current) % RX_RING_SIZE) {
 682		if (try_get_rx_skb(dpriv, dev) < 0)
 683			break;
 684		dpriv->rx_dirty++;
 685	}
 686	dscc4_rx_update(dpriv, dev);
 687	rx_fd->state2 = 0x00000000;
 688	rx_fd->end = cpu_to_le32(0xbabeface);
 689}
 690
 691static void dscc4_free1(struct pci_dev *pdev)
 692{
 693	struct dscc4_pci_priv *ppriv;
 694	struct dscc4_dev_priv *root;
 695	int i;
 696
 697	ppriv = pci_get_drvdata(pdev);
 698	root = ppriv->root;
 699
 700	for (i = 0; i < dev_per_card; i++)
 701		unregister_hdlc_device(dscc4_to_dev(root + i));
 702
 703	pci_set_drvdata(pdev, NULL);
 704
 705	for (i = 0; i < dev_per_card; i++)
 706		free_netdev(root[i].dev);
 707	kfree(root);
 708	kfree(ppriv);
 709}
 710
 711static int __devinit dscc4_init_one(struct pci_dev *pdev,
 712				  const struct pci_device_id *ent)
 713{
 714	struct dscc4_pci_priv *priv;
 715	struct dscc4_dev_priv *dpriv;
 716	void __iomem *ioaddr;
 717	int i, rc;
 718
 719	printk(KERN_DEBUG "%s", version);
 720
 721	rc = pci_enable_device(pdev);
 722	if (rc < 0)
 723		goto out;
 724
 725	rc = pci_request_region(pdev, 0, "registers");
 726	if (rc < 0) {
 727		pr_err("can't reserve MMIO region (regs)\n");
 728	        goto err_disable_0;
 729	}
 730	rc = pci_request_region(pdev, 1, "LBI interface");
 731	if (rc < 0) {
 732		pr_err("can't reserve MMIO region (lbi)\n");
 733	        goto err_free_mmio_region_1;
 734	}
 735
 736	ioaddr = pci_ioremap_bar(pdev, 0);
 737	if (!ioaddr) {
 738		pr_err("cannot remap MMIO region %llx @ %llx\n",
 739		       (unsigned long long)pci_resource_len(pdev, 0),
 740		       (unsigned long long)pci_resource_start(pdev, 0));
 741		rc = -EIO;
 742		goto err_free_mmio_regions_2;
 743	}
 744	printk(KERN_DEBUG "Siemens DSCC4, MMIO at %#llx (regs), %#llx (lbi), IRQ %d\n",
 745	        (unsigned long long)pci_resource_start(pdev, 0),
 746	        (unsigned long long)pci_resource_start(pdev, 1), pdev->irq);
 747
 748	/* Cf errata DS5 p.2 */
 749	pci_write_config_byte(pdev, PCI_LATENCY_TIMER, 0xf8);
 750	pci_set_master(pdev);
 751
 752	rc = dscc4_found1(pdev, ioaddr);
 753	if (rc < 0)
 754	        goto err_iounmap_3;
 755
 756	priv = pci_get_drvdata(pdev);
 757
 758	rc = request_irq(pdev->irq, dscc4_irq, IRQF_SHARED, DRV_NAME, priv->root);
 759	if (rc < 0) {
 760		pr_warn("IRQ %d busy\n", pdev->irq);
 761		goto err_release_4;
 762	}
 763
 764	/* power up/little endian/dma core controlled via lrda/ltda */
 765	writel(0x00000001, ioaddr + GMODE);
 766	/* Shared interrupt queue */
 767	{
 768		u32 bits;
 769
 770		bits = (IRQ_RING_SIZE >> 5) - 1;
 771		bits |= bits << 4;
 772		bits |= bits << 8;
 773		bits |= bits << 16;
 774		writel(bits, ioaddr + IQLENR0);
 775	}
 776	/* Global interrupt queue */
 777	writel((u32)(((IRQ_RING_SIZE >> 5) - 1) << 20), ioaddr + IQLENR1);
 778	priv->iqcfg = (__le32 *) pci_alloc_consistent(pdev,
 779		IRQ_RING_SIZE*sizeof(__le32), &priv->iqcfg_dma);
 780	if (!priv->iqcfg)
 781		goto err_free_irq_5;
 782	writel(priv->iqcfg_dma, ioaddr + IQCFG);
 783
 784	rc = -ENOMEM;
 785
 786	/*
 787	 * SCC 0-3 private rx/tx irq structures
 788	 * IQRX/TXi needs to be set soon. Learned it the hard way...
 789	 */
 790	for (i = 0; i < dev_per_card; i++) {
 791		dpriv = priv->root + i;
 792		dpriv->iqtx = (__le32 *) pci_alloc_consistent(pdev,
 793			IRQ_RING_SIZE*sizeof(u32), &dpriv->iqtx_dma);
 794		if (!dpriv->iqtx)
 795			goto err_free_iqtx_6;
 796		writel(dpriv->iqtx_dma, ioaddr + IQTX0 + i*4);
 797	}
 798	for (i = 0; i < dev_per_card; i++) {
 799		dpriv = priv->root + i;
 800		dpriv->iqrx = (__le32 *) pci_alloc_consistent(pdev,
 801			IRQ_RING_SIZE*sizeof(u32), &dpriv->iqrx_dma);
 802		if (!dpriv->iqrx)
 803			goto err_free_iqrx_7;
 804		writel(dpriv->iqrx_dma, ioaddr + IQRX0 + i*4);
 805	}
 806
 807	/* Cf application hint. Beware of hard-lock condition on threshold. */
 808	writel(0x42104000, ioaddr + FIFOCR1);
 809	//writel(0x9ce69800, ioaddr + FIFOCR2);
 810	writel(0xdef6d800, ioaddr + FIFOCR2);
 811	//writel(0x11111111, ioaddr + FIFOCR4);
 812	writel(0x18181818, ioaddr + FIFOCR4);
 813	// FIXME: should depend on the chipset revision
 814	writel(0x0000000e, ioaddr + FIFOCR3);
 815
 816	writel(0xff200001, ioaddr + GCMDR);
 817
 818	rc = 0;
 819out:
 820	return rc;
 821
 822err_free_iqrx_7:
 823	while (--i >= 0) {
 824		dpriv = priv->root + i;
 825		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
 826				    dpriv->iqrx, dpriv->iqrx_dma);
 827	}
 828	i = dev_per_card;
 829err_free_iqtx_6:
 830	while (--i >= 0) {
 831		dpriv = priv->root + i;
 832		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
 833				    dpriv->iqtx, dpriv->iqtx_dma);
 834	}
 835	pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32), priv->iqcfg,
 836			    priv->iqcfg_dma);
 837err_free_irq_5:
 838	free_irq(pdev->irq, priv->root);
 839err_release_4:
 840	dscc4_free1(pdev);
 841err_iounmap_3:
 842	iounmap (ioaddr);
 843err_free_mmio_regions_2:
 844	pci_release_region(pdev, 1);
 845err_free_mmio_region_1:
 846	pci_release_region(pdev, 0);
 847err_disable_0:
 848	pci_disable_device(pdev);
 849	goto out;
 850};
 851
 852/*
 853 * Let's hope the default values are decent enough to protect my
 854 * feet from the user's gun - Ueimor
 855 */
 856static void dscc4_init_registers(struct dscc4_dev_priv *dpriv,
 857				 struct net_device *dev)
 858{
 859	/* No interrupts, SCC core disabled. Let's relax */
 860	scc_writel(0x00000000, dpriv, dev, CCR0);
 861
 862	scc_writel(LengthCheck | (HDLC_MAX_MRU >> 5), dpriv, dev, RLCR);
 863
 864	/*
 865	 * No address recognition/crc-CCITT/cts enabled
 866	 * Shared flags transmission disabled - cf errata DS5 p.11
 867	 * Carrier detect disabled - cf errata p.14
 868	 * FIXME: carrier detection/polarity may be handled more gracefully.
 869	 */
 870	scc_writel(0x02408000, dpriv, dev, CCR1);
 871
 872	/* crc not forwarded - Cf errata DS5 p.11 */
 873	scc_writel(0x00050008 & ~RxActivate, dpriv, dev, CCR2);
 874	// crc forwarded
 875	//scc_writel(0x00250008 & ~RxActivate, dpriv, dev, CCR2);
 876}
 877
 878static inline int dscc4_set_quartz(struct dscc4_dev_priv *dpriv, int hz)
 879{
 880	int ret = 0;
 881
 882	if ((hz < 0) || (hz > DSCC4_HZ_MAX))
 883		ret = -EOPNOTSUPP;
 884	else
 885		dpriv->pci_priv->xtal_hz = hz;
 886
 887	return ret;
 888}
 889
 890static const struct net_device_ops dscc4_ops = {
 891	.ndo_open       = dscc4_open,
 892	.ndo_stop       = dscc4_close,
 893	.ndo_change_mtu = hdlc_change_mtu,
 894	.ndo_start_xmit = hdlc_start_xmit,
 895	.ndo_do_ioctl   = dscc4_ioctl,
 896	.ndo_tx_timeout = dscc4_tx_timeout,
 897};
 898
 899static int dscc4_found1(struct pci_dev *pdev, void __iomem *ioaddr)
 900{
 901	struct dscc4_pci_priv *ppriv;
 902	struct dscc4_dev_priv *root;
 903	int i, ret = -ENOMEM;
 904
 905	root = kcalloc(dev_per_card, sizeof(*root), GFP_KERNEL);
 906	if (!root) {
 907		pr_err("can't allocate data\n");
 908		goto err_out;
 909	}
 910
 911	for (i = 0; i < dev_per_card; i++) {
 912		root[i].dev = alloc_hdlcdev(root + i);
 913		if (!root[i].dev)
 914			goto err_free_dev;
 915	}
 916
 917	ppriv = kzalloc(sizeof(*ppriv), GFP_KERNEL);
 918	if (!ppriv) {
 919		pr_err("can't allocate private data\n");
 920		goto err_free_dev;
 921	}
 922
 923	ppriv->root = root;
 924	spin_lock_init(&ppriv->lock);
 925
 926	for (i = 0; i < dev_per_card; i++) {
 927		struct dscc4_dev_priv *dpriv = root + i;
 928		struct net_device *d = dscc4_to_dev(dpriv);
 929		hdlc_device *hdlc = dev_to_hdlc(d);
 930
 931	        d->base_addr = (unsigned long)ioaddr;
 932	        d->irq = pdev->irq;
 933		d->netdev_ops = &dscc4_ops;
 934		d->watchdog_timeo = TX_TIMEOUT;
 935		SET_NETDEV_DEV(d, &pdev->dev);
 936
 937		dpriv->dev_id = i;
 938		dpriv->pci_priv = ppriv;
 939		dpriv->base_addr = ioaddr;
 940		spin_lock_init(&dpriv->lock);
 941
 942		hdlc->xmit = dscc4_start_xmit;
 943		hdlc->attach = dscc4_hdlc_attach;
 944
 945		dscc4_init_registers(dpriv, d);
 946		dpriv->parity = PARITY_CRC16_PR0_CCITT;
 947		dpriv->encoding = ENCODING_NRZ;
 948	
 949		ret = dscc4_init_ring(d);
 950		if (ret < 0)
 951			goto err_unregister;
 952
 953		ret = register_hdlc_device(d);
 954		if (ret < 0) {
 955			pr_err("unable to register\n");
 956			dscc4_release_ring(dpriv);
 957			goto err_unregister;
 958	        }
 959	}
 960
 961	ret = dscc4_set_quartz(root, quartz);
 962	if (ret < 0)
 963		goto err_unregister;
 964
 965	pci_set_drvdata(pdev, ppriv);
 966	return ret;
 967
 968err_unregister:
 969	while (i-- > 0) {
 970		dscc4_release_ring(root + i);
 971		unregister_hdlc_device(dscc4_to_dev(root + i));
 972	}
 973	kfree(ppriv);
 974	i = dev_per_card;
 975err_free_dev:
 976	while (i-- > 0)
 977		free_netdev(root[i].dev);
 978	kfree(root);
 979err_out:
 980	return ret;
 981};
 982
 983/* FIXME: get rid of the unneeded code */
 984static void dscc4_timer(unsigned long data)
 985{
 986	struct net_device *dev = (struct net_device *)data;
 987	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
 988//	struct dscc4_pci_priv *ppriv;
 989
 990	goto done;
 991done:
 992        dpriv->timer.expires = jiffies + TX_TIMEOUT;
 993        add_timer(&dpriv->timer);
 994}
 995
 996static void dscc4_tx_timeout(struct net_device *dev)
 997{
 998	/* FIXME: something is missing there */
 999}
1000
1001static int dscc4_loopback_check(struct dscc4_dev_priv *dpriv)
1002{
1003	sync_serial_settings *settings = &dpriv->settings;
1004
1005	if (settings->loopback && (settings->clock_type != CLOCK_INT)) {
1006		struct net_device *dev = dscc4_to_dev(dpriv);
1007
1008		netdev_info(dev, "loopback requires clock\n");
1009		return -1;
1010	}
1011	return 0;
1012}
1013
1014#ifdef CONFIG_DSCC4_PCI_RST
1015/*
1016 * Some DSCC4-based cards wires the GPIO port and the PCI #RST pin together
1017 * so as to provide a safe way to reset the asic while not the whole machine
1018 * rebooting.
1019 *
1020 * This code doesn't need to be efficient. Keep It Simple
1021 */
1022static void dscc4_pci_reset(struct pci_dev *pdev, void __iomem *ioaddr)
1023{
1024	int i;
1025
1026	mutex_lock(&dscc4_mutex);
1027	for (i = 0; i < 16; i++)
1028		pci_read_config_dword(pdev, i << 2, dscc4_pci_config_store + i);
1029
1030	/* Maximal LBI clock divider (who cares ?) and whole GPIO range. */
1031	writel(0x001c0000, ioaddr + GMODE);
1032	/* Configure GPIO port as output */
1033	writel(0x0000ffff, ioaddr + GPDIR);
1034	/* Disable interruption */
1035	writel(0x0000ffff, ioaddr + GPIM);
1036
1037	writel(0x0000ffff, ioaddr + GPDATA);
1038	writel(0x00000000, ioaddr + GPDATA);
1039
1040	/* Flush posted writes */
1041	readl(ioaddr + GSTAR);
1042
1043	schedule_timeout_uninterruptible(10);
1044
1045	for (i = 0; i < 16; i++)
1046		pci_write_config_dword(pdev, i << 2, dscc4_pci_config_store[i]);
1047	mutex_unlock(&dscc4_mutex);
1048}
1049#else
1050#define dscc4_pci_reset(pdev,ioaddr)	do {} while (0)
1051#endif /* CONFIG_DSCC4_PCI_RST */
1052
1053static int dscc4_open(struct net_device *dev)
1054{
1055	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1056	struct dscc4_pci_priv *ppriv;
1057	int ret = -EAGAIN;
1058
1059	if ((dscc4_loopback_check(dpriv) < 0))
1060		goto err;
1061
1062	if ((ret = hdlc_open(dev)))
1063		goto err;
1064
1065	ppriv = dpriv->pci_priv;
1066
1067	/*
1068	 * Due to various bugs, there is no way to reliably reset a
1069	 * specific port (manufacturer's dependent special PCI #RST wiring
1070	 * apart: it affects all ports). Thus the device goes in the best
1071	 * silent mode possible at dscc4_close() time and simply claims to
1072	 * be up if it's opened again. It still isn't possible to change
1073	 * the HDLC configuration without rebooting but at least the ports
1074	 * can be up/down ifconfig'ed without killing the host.
1075	 */
1076	if (dpriv->flags & FakeReset) {
1077		dpriv->flags &= ~FakeReset;
1078		scc_patchl(0, PowerUp, dpriv, dev, CCR0);
1079		scc_patchl(0, 0x00050000, dpriv, dev, CCR2);
1080		scc_writel(EventsMask, dpriv, dev, IMR);
1081		netdev_info(dev, "up again\n");
1082		goto done;
1083	}
1084
1085	/* IDT+IDR during XPR */
1086	dpriv->flags = NeedIDR | NeedIDT;
1087
1088	scc_patchl(0, PowerUp | Vis, dpriv, dev, CCR0);
1089
1090	/*
1091	 * The following is a bit paranoid...
1092	 *
1093	 * NB: the datasheet "...CEC will stay active if the SCC is in
1094	 * power-down mode or..." and CCR2.RAC = 1 are two different
1095	 * situations.
1096	 */
1097	if (scc_readl_star(dpriv, dev) & SccBusy) {
1098		netdev_err(dev, "busy - try later\n");
1099		ret = -EAGAIN;
1100		goto err_out;
1101	} else
1102		netdev_info(dev, "available - good\n");
1103
1104	scc_writel(EventsMask, dpriv, dev, IMR);
1105
1106	/* Posted write is flushed in the wait_ack loop */
1107	scc_writel(TxSccRes | RxSccRes, dpriv, dev, CMDR);
1108
1109	if ((ret = dscc4_wait_ack_cec(dpriv, dev, "Cec")) < 0)
1110		goto err_disable_scc_events;
1111
1112	/*
1113	 * I would expect XPR near CE completion (before ? after ?).
1114	 * At worst, this code won't see a late XPR and people
1115	 * will have to re-issue an ifconfig (this is harmless).
1116	 * WARNING, a really missing XPR usually means a hardware
1117	 * reset is needed. Suggestions anyone ?
1118	 */
1119	if ((ret = dscc4_xpr_ack(dpriv)) < 0) {
1120		pr_err("XPR timeout\n");
1121		goto err_disable_scc_events;
1122	}
1123	
1124	if (debug > 2)
1125		dscc4_tx_print(dev, dpriv, "Open");
1126
1127done:
1128	netif_start_queue(dev);
1129
1130        init_timer(&dpriv->timer);
1131        dpriv->timer.expires = jiffies + 10*HZ;
1132        dpriv->timer.data = (unsigned long)dev;
1133	dpriv->timer.function = dscc4_timer;
1134        add_timer(&dpriv->timer);
1135	netif_carrier_on(dev);
1136
1137	return 0;
1138
1139err_disable_scc_events:
1140	scc_writel(0xffffffff, dpriv, dev, IMR);
1141	scc_patchl(PowerUp | Vis, 0, dpriv, dev, CCR0);
1142err_out:
1143	hdlc_close(dev);
1144err:
1145	return ret;
1146}
1147
1148#ifdef DSCC4_POLLING
1149static int dscc4_tx_poll(struct dscc4_dev_priv *dpriv, struct net_device *dev)
1150{
1151	/* FIXME: it's gonna be easy (TM), for sure */
1152}
1153#endif /* DSCC4_POLLING */
1154
1155static netdev_tx_t dscc4_start_xmit(struct sk_buff *skb,
1156					  struct net_device *dev)
1157{
1158	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1159	struct dscc4_pci_priv *ppriv = dpriv->pci_priv;
1160	struct TxFD *tx_fd;
1161	int next;
1162
1163	next = dpriv->tx_current%TX_RING_SIZE;
1164	dpriv->tx_skbuff[next] = skb;
1165	tx_fd = dpriv->tx_fd + next;
1166	tx_fd->state = FrameEnd | TO_STATE_TX(skb->len);
1167	tx_fd->data = cpu_to_le32(pci_map_single(ppriv->pdev, skb->data, skb->len,
1168				     PCI_DMA_TODEVICE));
1169	tx_fd->complete = 0x00000000;
1170	tx_fd->jiffies = jiffies;
1171	mb();
1172
1173#ifdef DSCC4_POLLING
1174	spin_lock(&dpriv->lock);
1175	while (dscc4_tx_poll(dpriv, dev));
1176	spin_unlock(&dpriv->lock);
1177#endif
1178
1179	if (debug > 2)
1180		dscc4_tx_print(dev, dpriv, "Xmit");
1181	/* To be cleaned(unsigned int)/optimized. Later, ok ? */
1182	if (!((++dpriv->tx_current - dpriv->tx_dirty)%TX_RING_SIZE))
1183		netif_stop_queue(dev);
1184
1185	if (dscc4_tx_quiescent(dpriv, dev))
1186		dscc4_do_tx(dpriv, dev);
1187
1188	return NETDEV_TX_OK;
1189}
1190
1191static int dscc4_close(struct net_device *dev)
1192{
1193	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1194
1195	del_timer_sync(&dpriv->timer);
1196	netif_stop_queue(dev);
1197
1198	scc_patchl(PowerUp | Vis, 0, dpriv, dev, CCR0);
1199	scc_patchl(0x00050000, 0, dpriv, dev, CCR2);
1200	scc_writel(0xffffffff, dpriv, dev, IMR);
1201
1202	dpriv->flags |= FakeReset;
1203
1204	hdlc_close(dev);
1205
1206	return 0;
1207}
1208
1209static inline int dscc4_check_clock_ability(int port)
1210{
1211	int ret = 0;
1212
1213#ifdef CONFIG_DSCC4_PCISYNC
1214	if (port >= 2)
1215		ret = -1;
1216#endif
1217	return ret;
1218}
1219
1220/*
1221 * DS1 p.137: "There are a total of 13 different clocking modes..."
1222 *                                  ^^
1223 * Design choices:
1224 * - by default, assume a clock is provided on pin RxClk/TxClk (clock mode 0a).
1225 *   Clock mode 3b _should_ work but the testing seems to make this point
1226 *   dubious (DIY testing requires setting CCR0 at 0x00000033).
1227 *   This is supposed to provide least surprise "DTE like" behavior.
1228 * - if line rate is specified, clocks are assumed to be locally generated.
1229 *   A quartz must be available (on pin XTAL1). Modes 6b/7b are used. Choosing
1230 *   between these it automagically done according on the required frequency
1231 *   scaling. Of course some rounding may take place.
1232 * - no high speed mode (40Mb/s). May be trivial to do but I don't have an
1233 *   appropriate external clocking device for testing.
1234 * - no time-slot/clock mode 5: shameless laziness.
1235 *
1236 * The clock signals wiring can be (is ?) manufacturer dependent. Good luck.
1237 *
1238 * BIG FAT WARNING: if the device isn't provided enough clocking signal, it
1239 * won't pass the init sequence. For example, straight back-to-back DTE without
1240 * external clock will fail when dscc4_open() (<- 'ifconfig hdlcx xxx') is
1241 * called.
1242 *
1243 * Typos lurk in datasheet (missing divier in clock mode 7a figure 51 p.153
1244 * DS0 for example)
1245 *
1246 * Clock mode related bits of CCR0:
1247 *     +------------ TOE: output TxClk (0b/2b/3a/3b/6b/7a/7b only)
1248 *     | +---------- SSEL: sub-mode select 0 -> a, 1 -> b
1249 *     | | +-------- High Speed: say 0
1250 *     | | | +-+-+-- Clock Mode: 0..7
1251 *     | | | | | |
1252 * -+-+-+-+-+-+-+-+
1253 * x|x|5|4|3|2|1|0| lower bits
1254 *
1255 * Division factor of BRR: k = (N+1)x2^M (total divider = 16xk in mode 6b)
1256 *            +-+-+-+------------------ M (0..15)
1257 *            | | | |     +-+-+-+-+-+-- N (0..63)
1258 *    0 0 0 0 | | | | 0 0 | | | | | |
1259 * ...-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1260 *    f|e|d|c|b|a|9|8|7|6|5|4|3|2|1|0| lower bits
1261 *
1262 */
1263static int dscc4_set_clock(struct net_device *dev, u32 *bps, u32 *state)
1264{
1265	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1266	int ret = -1;
1267	u32 brr;
1268
1269	*state &= ~Ccr0ClockMask;
1270	if (*bps) { /* Clock generated - required for DCE */
1271		u32 n = 0, m = 0, divider;
1272		int xtal;
1273
1274		xtal = dpriv->pci_priv->xtal_hz;
1275		if (!xtal)
1276			goto done;
1277		if (dscc4_check_clock_ability(dpriv->dev_id) < 0)
1278			goto done;
1279		divider = xtal / *bps;
1280		if (divider > BRR_DIVIDER_MAX) {
1281			divider >>= 4;
1282			*state |= 0x00000036; /* Clock mode 6b (BRG/16) */
1283		} else
1284			*state |= 0x00000037; /* Clock mode 7b (BRG) */
1285		if (divider >> 22) {
1286			n = 63;
1287			m = 15;
1288		} else if (divider) {
1289			/* Extraction of the 6 highest weighted bits */
1290			m = 0;
1291			while (0xffffffc0 & divider) {
1292				m++;
1293				divider >>= 1;
1294			}
1295			n = divider;
1296		}
1297		brr = (m << 8) | n;
1298		divider = n << m;
1299		if (!(*state & 0x00000001)) /* ?b mode mask => clock mode 6b */
1300			divider <<= 4;
1301		*bps = xtal / divider;
1302	} else {
1303		/*
1304		 * External clock - DTE
1305		 * "state" already reflects Clock mode 0a (CCR0 = 0xzzzzzz00).
1306		 * Nothing more to be done
1307		 */
1308		brr = 0;
1309	}
1310	scc_writel(brr, dpriv, dev, BRR);
1311	ret = 0;
1312done:
1313	return ret;
1314}
1315
1316static int dscc4_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1317{
1318	sync_serial_settings __user *line = ifr->ifr_settings.ifs_ifsu.sync;
1319	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1320	const size_t size = sizeof(dpriv->settings);
1321	int ret = 0;
1322
1323        if (dev->flags & IFF_UP)
1324                return -EBUSY;
1325
1326	if (cmd != SIOCWANDEV)
1327		return -EOPNOTSUPP;
1328
1329	switch(ifr->ifr_settings.type) {
1330	case IF_GET_IFACE:
1331		ifr->ifr_settings.type = IF_IFACE_SYNC_SERIAL;
1332		if (ifr->ifr_settings.size < size) {
1333			ifr->ifr_settings.size = size; /* data size wanted */
1334			return -ENOBUFS;
1335		}
1336		if (copy_to_user(line, &dpriv->settings, size))
1337			return -EFAULT;
1338		break;
1339
1340	case IF_IFACE_SYNC_SERIAL:
1341		if (!capable(CAP_NET_ADMIN))
1342			return -EPERM;
1343
1344		if (dpriv->flags & FakeReset) {
1345			netdev_info(dev, "please reset the device before this command\n");
1346			return -EPERM;
1347		}
1348		if (copy_from_user(&dpriv->settings, line, size))
1349			return -EFAULT;
1350		ret = dscc4_set_iface(dpriv, dev);
1351		break;
1352
1353	default:
1354		ret = hdlc_ioctl(dev, ifr, cmd);
1355		break;
1356	}
1357
1358	return ret;
1359}
1360
1361static int dscc4_match(const struct thingie *p, int value)
1362{
1363	int i;
1364
1365	for (i = 0; p[i].define != -1; i++) {
1366		if (value == p[i].define)
1367			break;
1368	}
1369	if (p[i].define == -1)
1370		return -1;
1371	else
1372		return i;
1373}
1374
1375static int dscc4_clock_setting(struct dscc4_dev_priv *dpriv,
1376			       struct net_device *dev)
1377{
1378	sync_serial_settings *settings = &dpriv->settings;
1379	int ret = -EOPNOTSUPP;
1380	u32 bps, state;
1381
1382	bps = settings->clock_rate;
1383	state = scc_readl(dpriv, CCR0);
1384	if (dscc4_set_clock(dev, &bps, &state) < 0)
1385		goto done;
1386	if (bps) { /* DCE */
1387		printk(KERN_DEBUG "%s: generated RxClk (DCE)\n", dev->name);
1388		if (settings->clock_rate != bps) {
1389			printk(KERN_DEBUG "%s: clock adjusted (%08d -> %08d)\n",
1390				dev->name, settings->clock_rate, bps);
1391			settings->clock_rate = bps;
1392		}
1393	} else { /* DTE */
1394		state |= PowerUp | Vis;
1395		printk(KERN_DEBUG "%s: external RxClk (DTE)\n", dev->name);
1396	}
1397	scc_writel(state, dpriv, dev, CCR0);
1398	ret = 0;
1399done:
1400	return ret;
1401}
1402
1403static int dscc4_encoding_setting(struct dscc4_dev_priv *dpriv,
1404				  struct net_device *dev)
1405{
1406	static const struct thingie encoding[] = {
1407		{ ENCODING_NRZ,		0x00000000 },
1408		{ ENCODING_NRZI,	0x00200000 },
1409		{ ENCODING_FM_MARK,	0x00400000 },
1410		{ ENCODING_FM_SPACE,	0x00500000 },
1411		{ ENCODING_MANCHESTER,	0x00600000 },
1412		{ -1,			0}
1413	};
1414	int i, ret = 0;
1415
1416	i = dscc4_match(encoding, dpriv->encoding);
1417	if (i >= 0)
1418		scc_patchl(EncodingMask, encoding[i].bits, dpriv, dev, CCR0);
1419	else
1420		ret = -EOPNOTSUPP;
1421	return ret;
1422}
1423
1424static int dscc4_loopback_setting(struct dscc4_dev_priv *dpriv,
1425				  struct net_device *dev)
1426{
1427	sync_serial_settings *settings = &dpriv->settings;
1428	u32 state;
1429
1430	state = scc_readl(dpriv, CCR1);
1431	if (settings->loopback) {
1432		printk(KERN_DEBUG "%s: loopback\n", dev->name);
1433		state |= 0x00000100;
1434	} else {
1435		printk(KERN_DEBUG "%s: normal\n", dev->name);
1436		state &= ~0x00000100;
1437	}
1438	scc_writel(state, dpriv, dev, CCR1);
1439	return 0;
1440}
1441
1442static int dscc4_crc_setting(struct dscc4_dev_priv *dpriv,
1443			     struct net_device *dev)
1444{
1445	static const struct thingie crc[] = {
1446		{ PARITY_CRC16_PR0_CCITT,	0x00000010 },
1447		{ PARITY_CRC16_PR1_CCITT,	0x00000000 },
1448		{ PARITY_CRC32_PR0_CCITT,	0x00000011 },
1449		{ PARITY_CRC32_PR1_CCITT,	0x00000001 }
1450	};
1451	int i, ret = 0;
1452
1453	i = dscc4_match(crc, dpriv->parity);
1454	if (i >= 0)
1455		scc_patchl(CrcMask, crc[i].bits, dpriv, dev, CCR1);
1456	else
1457		ret = -EOPNOTSUPP;
1458	return ret;
1459}
1460
1461static int dscc4_set_iface(struct dscc4_dev_priv *dpriv, struct net_device *dev)
1462{
1463	struct {
1464		int (*action)(struct dscc4_dev_priv *, struct net_device *);
1465	} *p, do_setting[] = {
1466		{ dscc4_encoding_setting },
1467		{ dscc4_clock_setting },
1468		{ dscc4_loopback_setting },
1469		{ dscc4_crc_setting },
1470		{ NULL }
1471	};
1472	int ret = 0;
1473
1474	for (p = do_setting; p->action; p++) {
1475		if ((ret = p->action(dpriv, dev)) < 0)
1476			break;
1477	}
1478	return ret;
1479}
1480
1481static irqreturn_t dscc4_irq(int irq, void *token)
1482{
1483	struct dscc4_dev_priv *root = token;
1484	struct dscc4_pci_priv *priv;
1485	struct net_device *dev;
1486	void __iomem *ioaddr;
1487	u32 state;
1488	unsigned long flags;
1489	int i, handled = 1;
1490
1491	priv = root->pci_priv;
1492	dev = dscc4_to_dev(root);
1493
1494	spin_lock_irqsave(&priv->lock, flags);
1495
1496	ioaddr = root->base_addr;
1497
1498	state = readl(ioaddr + GSTAR);
1499	if (!state) {
1500		handled = 0;
1501		goto out;
1502	}
1503	if (debug > 3)
1504		printk(KERN_DEBUG "%s: GSTAR = 0x%08x\n", DRV_NAME, state);
1505	writel(state, ioaddr + GSTAR);
1506
1507	if (state & Arf) {
1508		netdev_err(dev, "failure (Arf). Harass the maintainer\n");
1509		goto out;
1510	}
1511	state &= ~ArAck;
1512	if (state & Cfg) {
1513		if (debug > 0)
1514			printk(KERN_DEBUG "%s: CfgIV\n", DRV_NAME);
1515		if (priv->iqcfg[priv->cfg_cur++%IRQ_RING_SIZE] & cpu_to_le32(Arf))
1516			netdev_err(dev, "CFG failed\n");
1517		if (!(state &= ~Cfg))
1518			goto out;
1519	}
1520	if (state & RxEvt) {
1521		i = dev_per_card - 1;
1522		do {
1523			dscc4_rx_irq(priv, root + i);
1524		} while (--i >= 0);
1525		state &= ~RxEvt;
1526	}
1527	if (state & TxEvt) {
1528		i = dev_per_card - 1;
1529		do {
1530			dscc4_tx_irq(priv, root + i);
1531		} while (--i >= 0);
1532		state &= ~TxEvt;
1533	}
1534out:
1535	spin_unlock_irqrestore(&priv->lock, flags);
1536	return IRQ_RETVAL(handled);
1537}
1538
1539static void dscc4_tx_irq(struct dscc4_pci_priv *ppriv,
1540				struct dscc4_dev_priv *dpriv)
1541{
1542	struct net_device *dev = dscc4_to_dev(dpriv);
1543	u32 state;
1544	int cur, loop = 0;
1545
1546try:
1547	cur = dpriv->iqtx_current%IRQ_RING_SIZE;
1548	state = le32_to_cpu(dpriv->iqtx[cur]);
1549	if (!state) {
1550		if (debug > 4)
1551			printk(KERN_DEBUG "%s: Tx ISR = 0x%08x\n", dev->name,
1552			       state);
1553		if ((debug > 1) && (loop > 1))
1554			printk(KERN_DEBUG "%s: Tx irq loop=%d\n", dev->name, loop);
1555		if (loop && netif_queue_stopped(dev))
1556			if ((dpriv->tx_current - dpriv->tx_dirty)%TX_RING_SIZE)
1557				netif_wake_queue(dev);
1558
1559		if (netif_running(dev) && dscc4_tx_quiescent(dpriv, dev) &&
1560		    !dscc4_tx_done(dpriv))
1561				dscc4_do_tx(dpriv, dev);
1562		return;
1563	}
1564	loop++;
1565	dpriv->iqtx[cur] = 0;
1566	dpriv->iqtx_current++;
1567
1568	if (state_check(state, dpriv, dev, "Tx") < 0)
1569		return;
1570
1571	if (state & SccEvt) {
1572		if (state & Alls) {
1573			struct sk_buff *skb;
1574			struct TxFD *tx_fd;
1575
1576			if (debug > 2)
1577				dscc4_tx_print(dev, dpriv, "Alls");
1578			/*
1579			 * DataComplete can't be trusted for Tx completion.
1580			 * Cf errata DS5 p.8
1581			 */
1582			cur = dpriv->tx_dirty%TX_RING_SIZE;
1583			tx_fd = dpriv->tx_fd + cur;
1584			skb = dpriv->tx_skbuff[cur];
1585			if (skb) {
1586				pci_unmap_single(ppriv->pdev, le32_to_cpu(tx_fd->data),
1587						 skb->len, PCI_DMA_TODEVICE);
1588				if (tx_fd->state & FrameEnd) {
1589					dev->stats.tx_packets++;
1590					dev->stats.tx_bytes += skb->len;
1591				}
1592				dev_kfree_skb_irq(skb);
1593				dpriv->tx_skbuff[cur] = NULL;
1594				++dpriv->tx_dirty;
1595			} else {
1596				if (debug > 1)
1597					netdev_err(dev, "Tx: NULL skb %d\n",
1598						   cur);
1599			}
1600			/*
1601			 * If the driver ends sending crap on the wire, it
1602			 * will be way easier to diagnose than the (not so)
1603			 * random freeze induced by null sized tx frames.
1604			 */
1605			tx_fd->data = tx_fd->next;
1606			tx_fd->state = FrameEnd | TO_STATE_TX(2*DUMMY_SKB_SIZE);
1607			tx_fd->complete = 0x00000000;
1608			tx_fd->jiffies = 0;
1609
1610			if (!(state &= ~Alls))
1611				goto try;
1612		}
1613		/*
1614		 * Transmit Data Underrun
1615		 */
1616		if (state & Xdu) {
1617			netdev_err(dev, "Tx Data Underrun. Ask maintainer\n");
1618			dpriv->flags = NeedIDT;
1619			/* Tx reset */
1620			writel(MTFi | Rdt,
1621			       dpriv->base_addr + 0x0c*dpriv->dev_id + CH0CFG);
1622			writel(Action, dpriv->base_addr + GCMDR);
1623			return;
1624		}
1625		if (state & Cts) {
1626			netdev_info(dev, "CTS transition\n");
1627			if (!(state &= ~Cts)) /* DEBUG */
1628				goto try;
1629		}
1630		if (state & Xmr) {
1631			/* Frame needs to be sent again - FIXME */
1632			netdev_err(dev, "Tx ReTx. Ask maintainer\n");
1633			if (!(state &= ~Xmr)) /* DEBUG */
1634				goto try;
1635		}
1636		if (state & Xpr) {
1637			void __iomem *scc_addr;
1638			unsigned long ring;
1639			int i;
1640
1641			/*
1642			 * - the busy condition happens (sometimes);
1643			 * - it doesn't seem to make the handler unreliable.
1644			 */
1645			for (i = 1; i; i <<= 1) {
1646				if (!(scc_readl_star(dpriv, dev) & SccBusy))
1647					break;
1648			}
1649			if (!i)
1650				netdev_info(dev, "busy in irq\n");
1651
1652			scc_addr = dpriv->base_addr + 0x0c*dpriv->dev_id;
1653			/* Keep this order: IDT before IDR */
1654			if (dpriv->flags & NeedIDT) {
1655				if (debug > 2)
1656					dscc4_tx_print(dev, dpriv, "Xpr");
1657				ring = dpriv->tx_fd_dma +
1658				       (dpriv->tx_dirty%TX_RING_SIZE)*
1659				       sizeof(struct TxFD);
1660				writel(ring, scc_addr + CH0BTDA);
1661				dscc4_do_tx(dpriv, dev);
1662				writel(MTFi | Idt, scc_addr + CH0CFG);
1663				if (dscc4_do_action(dev, "IDT") < 0)
1664					goto err_xpr;
1665				dpriv->flags &= ~NeedIDT;
1666			}
1667			if (dpriv->flags & NeedIDR) {
1668				ring = dpriv->rx_fd_dma +
1669				       (dpriv->rx_current%RX_RING_SIZE)*
1670				       sizeof(struct RxFD);
1671				writel(ring, scc_addr + CH0BRDA);
1672				dscc4_rx_update(dpriv, dev);
1673				writel(MTFi | Idr, scc_addr + CH0CFG);
1674				if (dscc4_do_action(dev, "IDR") < 0)
1675					goto err_xpr;
1676				dpriv->flags &= ~NeedIDR;
1677				smp_wmb();
1678				/* Activate receiver and misc */
1679				scc_writel(0x08050008, dpriv, dev, CCR2);
1680			}
1681		err_xpr:
1682			if (!(state &= ~Xpr))
1683				goto try;
1684		}
1685		if (state & Cd) {
1686			if (debug > 0)
1687				netdev_info(dev, "CD transition\n");
1688			if (!(state &= ~Cd)) /* DEBUG */
1689				goto try;
1690		}
1691	} else { /* ! SccEvt */
1692		if (state & Hi) {
1693#ifdef DSCC4_POLLING
1694			while (!dscc4_tx_poll(dpriv, dev));
1695#endif
1696			netdev_info(dev, "Tx Hi\n");
1697			state &= ~Hi;
1698		}
1699		if (state & Err) {
1700			netdev_info(dev, "Tx ERR\n");
1701			dev->stats.tx_errors++;
1702			state &= ~Err;
1703		}
1704	}
1705	goto try;
1706}
1707
1708static void dscc4_rx_irq(struct dscc4_pci_priv *priv,
1709				    struct dscc4_dev_priv *dpriv)
1710{
1711	struct net_device *dev = dscc4_to_dev(dpriv);
1712	u32 state;
1713	int cur;
1714
1715try:
1716	cur = dpriv->iqrx_current%IRQ_RING_SIZE;
1717	state = le32_to_cpu(dpriv->iqrx[cur]);
1718	if (!state)
1719		return;
1720	dpriv->iqrx[cur] = 0;
1721	dpriv->iqrx_current++;
1722
1723	if (state_check(state, dpriv, dev, "Rx") < 0)
1724		return;
1725
1726	if (!(state & SccEvt)){
1727		struct RxFD *rx_fd;
1728
1729		if (debug > 4)
1730			printk(KERN_DEBUG "%s: Rx ISR = 0x%08x\n", dev->name,
1731			       state);
1732		state &= 0x00ffffff;
1733		if (state & Err) { /* Hold or reset */
1734			printk(KERN_DEBUG "%s: Rx ERR\n", dev->name);
1735			cur = dpriv->rx_current%RX_RING_SIZE;
1736			rx_fd = dpriv->rx_fd + cur;
1737			/*
1738			 * Presume we're not facing a DMAC receiver reset.
1739			 * As We use the rx size-filtering feature of the
1740			 * DSCC4, the beginning of a new frame is waiting in
1741			 * the rx fifo. I bet a Receive Data Overflow will
1742			 * happen most of time but let's try and avoid it.
1743			 * Btw (as for RDO) if one experiences ERR whereas
1744			 * the system looks rather idle, there may be a
1745			 * problem with latency. In this case, increasing
1746			 * RX_RING_SIZE may help.
1747			 */
1748			//while (dpriv->rx_needs_refill) {
1749				while (!(rx_fd->state1 & Hold)) {
1750					rx_fd++;
1751					cur++;
1752					if (!(cur = cur%RX_RING_SIZE))
1753						rx_fd = dpriv->rx_fd;
1754				}
1755				//dpriv->rx_needs_refill--;
1756				try_get_rx_skb(dpriv, dev);
1757				if (!rx_fd->data)
1758					goto try;
1759				rx_fd->state1 &= ~Hold;
1760				rx_fd->state2 = 0x00000000;
1761				rx_fd->end = cpu_to_le32(0xbabeface);
1762			//}
1763			goto try;
1764		}
1765		if (state & Fi) {
1766			dscc4_rx_skb(dpriv, dev);
1767			goto try;
1768		}
1769		if (state & Hi ) { /* HI bit */
1770			netdev_info(dev, "Rx Hi\n");
1771			state &= ~Hi;
1772			goto try;
1773		}
1774	} else { /* SccEvt */
1775		if (debug > 1) {
1776			//FIXME: verifier la presence de tous les evenements
1777		static struct {
1778			u32 mask;
1779			const char *irq_name;
1780		} evts[] = {
1781			{ 0x00008000, "TIN"},
1782			{ 0x00000020, "RSC"},
1783			{ 0x00000010, "PCE"},
1784			{ 0x00000008, "PLLA"},
1785			{ 0, NULL}
1786		}, *evt;
1787
1788		for (evt = evts; evt->irq_name; evt++) {
1789			if (state & evt->mask) {
1790					printk(KERN_DEBUG "%s: %s\n",
1791						dev->name, evt->irq_name);
1792				if (!(state &= ~evt->mask))
1793					goto try;
1794			}
1795		}
1796		} else {
1797			if (!(state &= ~0x0000c03c))
1798				goto try;
1799		}
1800		if (state & Cts) {
1801			netdev_info(dev, "CTS transition\n");
1802			if (!(state &= ~Cts)) /* DEBUG */
1803				goto try;
1804		}
1805		/*
1806		 * Receive Data Overflow (FIXME: fscked)
1807		 */
1808		if (state & Rdo) {
1809			struct RxFD *rx_fd;
1810			void __iomem *scc_addr;
1811			int cur;
1812
1813			//if (debug)
1814			//	dscc4_rx_dump(dpriv);
1815			scc_addr = dpriv->base_addr + 0x0c*dpriv->dev_id;
1816
1817			scc_patchl(RxActivate, 0, dpriv, dev, CCR2);
1818			/*
1819			 * This has no effect. Why ?
1820			 * ORed with TxSccRes, one sees the CFG ack (for
1821			 * the TX part only).
1822			 */
1823			scc_writel(RxSccRes, dpriv, dev, CMDR);
1824			dpriv->flags |= RdoSet;
1825
1826			/*
1827			 * Let's try and save something in the received data.
1828			 * rx_current must be incremented at least once to
1829			 * avoid HOLD in the BRDA-to-be-pointed desc.
1830			 */
1831			do {
1832				cur = dpriv->rx_current++%RX_RING_SIZE;
1833				rx_fd = dpriv->rx_fd + cur;
1834				if (!(rx_fd->state2 & DataComplete))
1835					break;
1836				if (rx_fd->state2 & FrameAborted) {
1837					dev->stats.rx_over_errors++;
1838					rx_fd->state1 |= Hold;
1839					rx_fd->state2 = 0x00000000;
1840					rx_fd->end = cpu_to_le32(0xbabeface);
1841				} else
1842					dscc4_rx_skb(dpriv, dev);
1843			} while (1);
1844
1845			if (debug > 0) {
1846				if (dpriv->flags & RdoSet)
1847					printk(KERN_DEBUG
1848					       "%s: no RDO in Rx data\n", DRV_NAME);
1849			}
1850#ifdef DSCC4_RDO_EXPERIMENTAL_RECOVERY
1851			/*
1852			 * FIXME: must the reset be this violent ?
1853			 */
1854#warning "FIXME: CH0BRDA"
1855			writel(dpriv->rx_fd_dma +
1856			       (dpriv->rx_current%RX_RING_SIZE)*
1857			       sizeof(struct RxFD), scc_addr + CH0BRDA);
1858			writel(MTFi|Rdr|Idr, scc_addr + CH0CFG);
1859			if (dscc4_do_action(dev, "RDR") < 0) {
1860				netdev_err(dev, "RDO recovery failed(RDR)\n");
1861				goto rdo_end;
1862			}
1863			writel(MTFi|Idr, scc_addr + CH0CFG);
1864			if (dscc4_do_action(dev, "IDR") < 0) {
1865				netdev_err(dev, "RDO recovery failed(IDR)\n");
1866				goto rdo_end;
1867			}
1868		rdo_end:
1869#endif
1870			scc_patchl(0, RxActivate, dpriv, dev, CCR2);
1871			goto try;
1872		}
1873		if (state & Cd) {
1874			netdev_info(dev, "CD transition\n");
1875			if (!(state &= ~Cd)) /* DEBUG */
1876				goto try;
1877		}
1878		if (state & Flex) {
1879			printk(KERN_DEBUG "%s: Flex. Ttttt...\n", DRV_NAME);
1880			if (!(state &= ~Flex))
1881				goto try;
1882		}
1883	}
1884}
1885
1886/*
1887 * I had expected the following to work for the first descriptor
1888 * (tx_fd->state = 0xc0000000)
1889 * - Hold=1 (don't try and branch to the next descripto);
1890 * - No=0 (I want an empty data section, i.e. size=0);
1891 * - Fe=1 (required by No=0 or we got an Err irq and must reset).
1892 * It failed and locked solid. Thus the introduction of a dummy skb.
1893 * Problem is acknowledged in errata sheet DS5. Joy :o/
1894 */
1895static struct sk_buff *dscc4_init_dummy_skb(struct dscc4_dev_priv *dpriv)
1896{
1897	struct sk_buff *skb;
1898
1899	skb = dev_alloc_skb(DUMMY_SKB_SIZE);
1900	if (skb) {
1901		int last = dpriv->tx_dirty%TX_RING_SIZE;
1902		struct TxFD *tx_fd = dpriv->tx_fd + last;
1903
1904		skb->len = DUMMY_SKB_SIZE;
1905		skb_copy_to_linear_data(skb, version,
1906					strlen(version) % DUMMY_SKB_SIZE);
1907		tx_fd->state = FrameEnd | TO_STATE_TX(DUMMY_SKB_SIZE);
1908		tx_fd->data = cpu_to_le32(pci_map_single(dpriv->pci_priv->pdev,
1909					     skb->data, DUMMY_SKB_SIZE,
1910					     PCI_DMA_TODEVICE));
1911		dpriv->tx_skbuff[last] = skb;
1912	}
1913	return skb;
1914}
1915
1916static int dscc4_init_ring(struct net_device *dev)
1917{
1918	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1919	struct pci_dev *pdev = dpriv->pci_priv->pdev;
1920	struct TxFD *tx_fd;
1921	struct RxFD *rx_fd;
1922	void *ring;
1923	int i;
1924
1925	ring = pci_alloc_consistent(pdev, RX_TOTAL_SIZE, &dpriv->rx_fd_dma);
1926	if (!ring)
1927		goto err_out;
1928	dpriv->rx_fd = rx_fd = (struct RxFD *) ring;
1929
1930	ring = pci_alloc_consistent(pdev, TX_TOTAL_SIZE, &dpriv->tx_fd_dma);
1931	if (!ring)
1932		goto err_free_dma_rx;
1933	dpriv->tx_fd = tx_fd = (struct TxFD *) ring;
1934
1935	memset(dpriv->tx_skbuff, 0, sizeof(struct sk_buff *)*TX_RING_SIZE);
1936	dpriv->tx_dirty = 0xffffffff;
1937	i = dpriv->tx_current = 0;
1938	do {
1939		tx_fd->state = FrameEnd | TO_STATE_TX(2*DUMMY_SKB_SIZE);
1940		tx_fd->complete = 0x00000000;
1941	        /* FIXME: NULL should be ok - to be tried */
1942	        tx_fd->data = cpu_to_le32(dpriv->tx_fd_dma);
1943		(tx_fd++)->next = cpu_to_le32(dpriv->tx_fd_dma +
1944					(++i%TX_RING_SIZE)*sizeof(*tx_fd));
1945	} while (i < TX_RING_SIZE);
1946
1947	if (!dscc4_init_dummy_skb(dpriv))
1948		goto err_free_dma_tx;
1949
1950	memset(dpriv->rx_skbuff, 0, sizeof(struct sk_buff *)*RX_RING_SIZE);
1951	i = dpriv->rx_dirty = dpriv->rx_current = 0;
1952	do {
1953		/* size set by the host. Multiple of 4 bytes please */
1954	        rx_fd->state1 = HiDesc;
1955	        rx_fd->state2 = 0x00000000;
1956	        rx_fd->end = cpu_to_le32(0xbabeface);
1957	        rx_fd->state1 |= TO_STATE_RX(HDLC_MAX_MRU);
1958		// FIXME: return value verifiee mais traitement suspect
1959		if (try_get_rx_skb(dpriv, dev) >= 0)
1960			dpriv->rx_dirty++;
1961		(rx_fd++)->next = cpu_to_le32(dpriv->rx_fd_dma +
1962					(++i%RX_RING_SIZE)*sizeof(*rx_fd));
1963	} while (i < RX_RING_SIZE);
1964
1965	return 0;
1966
1967err_free_dma_tx:
1968	pci_free_consistent(pdev, TX_TOTAL_SIZE, ring, dpriv->tx_fd_dma);
1969err_free_dma_rx:
1970	pci_free_consistent(pdev, RX_TOTAL_SIZE, rx_fd, dpriv->rx_fd_dma);
1971err_out:
1972	return -ENOMEM;
1973}
1974
1975static void __devexit dscc4_remove_one(struct pci_dev *pdev)
1976{
1977	struct dscc4_pci_priv *ppriv;
1978	struct dscc4_dev_priv *root;
1979	void __iomem *ioaddr;
1980	int i;
1981
1982	ppriv = pci_get_drvdata(pdev);
1983	root = ppriv->root;
1984
1985	ioaddr = root->base_addr;
1986
1987	dscc4_pci_reset(pdev, ioaddr);
1988
1989	free_irq(pdev->irq, root);
1990	pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32), ppriv->iqcfg,
1991			    ppriv->iqcfg_dma);
1992	for (i = 0; i < dev_per_card; i++) {
1993		struct dscc4_dev_priv *dpriv = root + i;
1994
1995		dscc4_release_ring(dpriv);
1996		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
1997				    dpriv->iqrx, dpriv->iqrx_dma);
1998		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
1999				    dpriv->iqtx, dpriv->iqtx_dma);
2000	}
2001
2002	dscc4_free1(pdev);
2003
2004	iounmap(ioaddr);
2005
2006	pci_release_region(pdev, 1);
2007	pci_release_region(pdev, 0);
2008
2009	pci_disable_device(pdev);
2010}
2011
2012static int dscc4_hdlc_attach(struct net_device *dev, unsigned short encoding,
2013	unsigned short parity)
2014{
2015	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
2016
2017	if (encoding != ENCODING_NRZ &&
2018	    encoding != ENCODING_NRZI &&
2019	    encoding != ENCODING_FM_MARK &&
2020	    encoding != ENCODING_FM_SPACE &&
2021	    encoding != ENCODING_MANCHESTER)
2022		return -EINVAL;
2023
2024	if (parity != PARITY_NONE &&
2025	    parity != PARITY_CRC16_PR0_CCITT &&
2026	    parity != PARITY_CRC16_PR1_CCITT &&
2027	    parity != PARITY_CRC32_PR0_CCITT &&
2028	    parity != PARITY_CRC32_PR1_CCITT)
2029		return -EINVAL;
2030
2031        dpriv->encoding = encoding;
2032        dpriv->parity = parity;
2033	return 0;
2034}
2035
2036#ifndef MODULE
2037static int __init dscc4_setup(char *str)
2038{
2039	int *args[] = { &debug, &quartz, NULL }, **p = args;
2040
2041	while (*p && (get_option(&str, *p) == 2))
2042		p++;
2043	return 1;
2044}
2045
2046__setup("dscc4.setup=", dscc4_setup);
2047#endif
2048
2049static DEFINE_PCI_DEVICE_TABLE(dscc4_pci_tbl) = {
2050	{ PCI_VENDOR_ID_SIEMENS, PCI_DEVICE_ID_SIEMENS_DSCC4,
2051	        PCI_ANY_ID, PCI_ANY_ID, },
2052	{ 0,}
2053};
2054MODULE_DEVICE_TABLE(pci, dscc4_pci_tbl);
2055
2056static struct pci_driver dscc4_driver = {
2057	.name		= DRV_NAME,
2058	.id_table	= dscc4_pci_tbl,
2059	.probe		= dscc4_init_one,
2060	.remove		= __devexit_p(dscc4_remove_one),
2061};
2062
2063static int __init dscc4_init_module(void)
2064{
2065	return pci_register_driver(&dscc4_driver);
2066}
2067
2068static void __exit dscc4_cleanup_module(void)
2069{
2070	pci_unregister_driver(&dscc4_driver);
2071}
2072
2073module_init(dscc4_init_module);
2074module_exit(dscc4_cleanup_module);