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