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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(msecs_to_jiffies(100));
 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(msecs_to_jiffies(100));
 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	for (i = 0; i < dev_per_card; i++)
 703		free_netdev(root[i].dev);
 704	kfree(root);
 705	kfree(ppriv);
 706}
 707
 708static int dscc4_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 709{
 710	struct dscc4_pci_priv *priv;
 711	struct dscc4_dev_priv *dpriv;
 712	void __iomem *ioaddr;
 713	int i, rc;
 714
 715	printk(KERN_DEBUG "%s", version);
 716
 717	rc = pci_enable_device(pdev);
 718	if (rc < 0)
 719		goto out;
 720
 721	rc = pci_request_region(pdev, 0, "registers");
 722	if (rc < 0) {
 723		pr_err("can't reserve MMIO region (regs)\n");
 724	        goto err_disable_0;
 725	}
 726	rc = pci_request_region(pdev, 1, "LBI interface");
 727	if (rc < 0) {
 728		pr_err("can't reserve MMIO region (lbi)\n");
 729	        goto err_free_mmio_region_1;
 730	}
 731
 732	ioaddr = pci_ioremap_bar(pdev, 0);
 733	if (!ioaddr) {
 734		pr_err("cannot remap MMIO region %llx @ %llx\n",
 735		       (unsigned long long)pci_resource_len(pdev, 0),
 736		       (unsigned long long)pci_resource_start(pdev, 0));
 737		rc = -EIO;
 738		goto err_free_mmio_regions_2;
 739	}
 740	printk(KERN_DEBUG "Siemens DSCC4, MMIO at %#llx (regs), %#llx (lbi), IRQ %d\n",
 741	        (unsigned long long)pci_resource_start(pdev, 0),
 742	        (unsigned long long)pci_resource_start(pdev, 1), pdev->irq);
 743
 744	/* Cf errata DS5 p.2 */
 745	pci_write_config_byte(pdev, PCI_LATENCY_TIMER, 0xf8);
 746	pci_set_master(pdev);
 747
 748	rc = dscc4_found1(pdev, ioaddr);
 749	if (rc < 0)
 750	        goto err_iounmap_3;
 751
 752	priv = pci_get_drvdata(pdev);
 753
 754	rc = request_irq(pdev->irq, dscc4_irq, IRQF_SHARED, DRV_NAME, priv->root);
 755	if (rc < 0) {
 756		pr_warn("IRQ %d busy\n", pdev->irq);
 757		goto err_release_4;
 758	}
 759
 760	/* power up/little endian/dma core controlled via lrda/ltda */
 761	writel(0x00000001, ioaddr + GMODE);
 762	/* Shared interrupt queue */
 763	{
 764		u32 bits;
 765
 766		bits = (IRQ_RING_SIZE >> 5) - 1;
 767		bits |= bits << 4;
 768		bits |= bits << 8;
 769		bits |= bits << 16;
 770		writel(bits, ioaddr + IQLENR0);
 771	}
 772	/* Global interrupt queue */
 773	writel((u32)(((IRQ_RING_SIZE >> 5) - 1) << 20), ioaddr + IQLENR1);
 774
 775	rc = -ENOMEM;
 776
 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	/*
 784	 * SCC 0-3 private rx/tx irq structures
 785	 * IQRX/TXi needs to be set soon. Learned it the hard way...
 786	 */
 787	for (i = 0; i < dev_per_card; i++) {
 788		dpriv = priv->root + i;
 789		dpriv->iqtx = (__le32 *) pci_alloc_consistent(pdev,
 790			IRQ_RING_SIZE*sizeof(u32), &dpriv->iqtx_dma);
 791		if (!dpriv->iqtx)
 792			goto err_free_iqtx_6;
 793		writel(dpriv->iqtx_dma, ioaddr + IQTX0 + i*4);
 794	}
 795	for (i = 0; i < dev_per_card; i++) {
 796		dpriv = priv->root + i;
 797		dpriv->iqrx = (__le32 *) pci_alloc_consistent(pdev,
 798			IRQ_RING_SIZE*sizeof(u32), &dpriv->iqrx_dma);
 799		if (!dpriv->iqrx)
 800			goto err_free_iqrx_7;
 801		writel(dpriv->iqrx_dma, ioaddr + IQRX0 + i*4);
 802	}
 803
 804	/* Cf application hint. Beware of hard-lock condition on threshold. */
 805	writel(0x42104000, ioaddr + FIFOCR1);
 806	//writel(0x9ce69800, ioaddr + FIFOCR2);
 807	writel(0xdef6d800, ioaddr + FIFOCR2);
 808	//writel(0x11111111, ioaddr + FIFOCR4);
 809	writel(0x18181818, ioaddr + FIFOCR4);
 810	// FIXME: should depend on the chipset revision
 811	writel(0x0000000e, ioaddr + FIFOCR3);
 812
 813	writel(0xff200001, ioaddr + GCMDR);
 814
 815	rc = 0;
 816out:
 817	return rc;
 818
 819err_free_iqrx_7:
 820	while (--i >= 0) {
 821		dpriv = priv->root + i;
 822		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
 823				    dpriv->iqrx, dpriv->iqrx_dma);
 824	}
 825	i = dev_per_card;
 826err_free_iqtx_6:
 827	while (--i >= 0) {
 828		dpriv = priv->root + i;
 829		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
 830				    dpriv->iqtx, dpriv->iqtx_dma);
 831	}
 832	pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32), priv->iqcfg,
 833			    priv->iqcfg_dma);
 834err_free_irq_5:
 835	free_irq(pdev->irq, priv->root);
 836err_release_4:
 837	dscc4_free1(pdev);
 838err_iounmap_3:
 839	iounmap (ioaddr);
 840err_free_mmio_regions_2:
 841	pci_release_region(pdev, 1);
 842err_free_mmio_region_1:
 843	pci_release_region(pdev, 0);
 844err_disable_0:
 845	pci_disable_device(pdev);
 846	goto out;
 847};
 848
 849/*
 850 * Let's hope the default values are decent enough to protect my
 851 * feet from the user's gun - Ueimor
 852 */
 853static void dscc4_init_registers(struct dscc4_dev_priv *dpriv,
 854				 struct net_device *dev)
 855{
 856	/* No interrupts, SCC core disabled. Let's relax */
 857	scc_writel(0x00000000, dpriv, dev, CCR0);
 858
 859	scc_writel(LengthCheck | (HDLC_MAX_MRU >> 5), dpriv, dev, RLCR);
 860
 861	/*
 862	 * No address recognition/crc-CCITT/cts enabled
 863	 * Shared flags transmission disabled - cf errata DS5 p.11
 864	 * Carrier detect disabled - cf errata p.14
 865	 * FIXME: carrier detection/polarity may be handled more gracefully.
 866	 */
 867	scc_writel(0x02408000, dpriv, dev, CCR1);
 868
 869	/* crc not forwarded - Cf errata DS5 p.11 */
 870	scc_writel(0x00050008 & ~RxActivate, dpriv, dev, CCR2);
 871	// crc forwarded
 872	//scc_writel(0x00250008 & ~RxActivate, dpriv, dev, CCR2);
 873}
 874
 875static inline int dscc4_set_quartz(struct dscc4_dev_priv *dpriv, int hz)
 876{
 877	int ret = 0;
 878
 879	if ((hz < 0) || (hz > DSCC4_HZ_MAX))
 880		ret = -EOPNOTSUPP;
 881	else
 882		dpriv->pci_priv->xtal_hz = hz;
 883
 884	return ret;
 885}
 886
 887static const struct net_device_ops dscc4_ops = {
 888	.ndo_open       = dscc4_open,
 889	.ndo_stop       = dscc4_close,
 890	.ndo_change_mtu = hdlc_change_mtu,
 891	.ndo_start_xmit = hdlc_start_xmit,
 892	.ndo_do_ioctl   = dscc4_ioctl,
 893	.ndo_tx_timeout = dscc4_tx_timeout,
 894};
 895
 896static int dscc4_found1(struct pci_dev *pdev, void __iomem *ioaddr)
 897{
 898	struct dscc4_pci_priv *ppriv;
 899	struct dscc4_dev_priv *root;
 900	int i, ret = -ENOMEM;
 901
 902	root = kcalloc(dev_per_card, sizeof(*root), GFP_KERNEL);
 903	if (!root)
 904		goto err_out;
 905
 906	for (i = 0; i < dev_per_card; i++) {
 907		root[i].dev = alloc_hdlcdev(root + i);
 908		if (!root[i].dev)
 909			goto err_free_dev;
 910	}
 911
 912	ppriv = kzalloc(sizeof(*ppriv), GFP_KERNEL);
 913	if (!ppriv)
 914		goto err_free_dev;
 915
 916	ppriv->root = root;
 917	spin_lock_init(&ppriv->lock);
 918
 919	for (i = 0; i < dev_per_card; i++) {
 920		struct dscc4_dev_priv *dpriv = root + i;
 921		struct net_device *d = dscc4_to_dev(dpriv);
 922		hdlc_device *hdlc = dev_to_hdlc(d);
 923
 924	        d->base_addr = (unsigned long)ioaddr;
 925	        d->irq = pdev->irq;
 926		d->netdev_ops = &dscc4_ops;
 927		d->watchdog_timeo = TX_TIMEOUT;
 928		SET_NETDEV_DEV(d, &pdev->dev);
 929
 930		dpriv->dev_id = i;
 931		dpriv->pci_priv = ppriv;
 932		dpriv->base_addr = ioaddr;
 933		spin_lock_init(&dpriv->lock);
 934
 935		hdlc->xmit = dscc4_start_xmit;
 936		hdlc->attach = dscc4_hdlc_attach;
 937
 938		dscc4_init_registers(dpriv, d);
 939		dpriv->parity = PARITY_CRC16_PR0_CCITT;
 940		dpriv->encoding = ENCODING_NRZ;
 941	
 942		ret = dscc4_init_ring(d);
 943		if (ret < 0)
 944			goto err_unregister;
 945
 946		ret = register_hdlc_device(d);
 947		if (ret < 0) {
 948			pr_err("unable to register\n");
 949			dscc4_release_ring(dpriv);
 950			goto err_unregister;
 951	        }
 952	}
 953
 954	ret = dscc4_set_quartz(root, quartz);
 955	if (ret < 0)
 956		goto err_unregister;
 957
 958	pci_set_drvdata(pdev, ppriv);
 959	return ret;
 960
 961err_unregister:
 962	while (i-- > 0) {
 963		dscc4_release_ring(root + i);
 964		unregister_hdlc_device(dscc4_to_dev(root + i));
 965	}
 966	kfree(ppriv);
 967	i = dev_per_card;
 968err_free_dev:
 969	while (i-- > 0)
 970		free_netdev(root[i].dev);
 971	kfree(root);
 972err_out:
 973	return ret;
 974};
 975
 976/* FIXME: get rid of the unneeded code */
 977static void dscc4_timer(unsigned long data)
 978{
 979	struct net_device *dev = (struct net_device *)data;
 980	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
 981//	struct dscc4_pci_priv *ppriv;
 982
 983	goto done;
 984done:
 985        dpriv->timer.expires = jiffies + TX_TIMEOUT;
 986        add_timer(&dpriv->timer);
 987}
 988
 989static void dscc4_tx_timeout(struct net_device *dev)
 990{
 991	/* FIXME: something is missing there */
 992}
 993
 994static int dscc4_loopback_check(struct dscc4_dev_priv *dpriv)
 995{
 996	sync_serial_settings *settings = &dpriv->settings;
 997
 998	if (settings->loopback && (settings->clock_type != CLOCK_INT)) {
 999		struct net_device *dev = dscc4_to_dev(dpriv);
1000
1001		netdev_info(dev, "loopback requires clock\n");
1002		return -1;
1003	}
1004	return 0;
1005}
1006
1007#ifdef CONFIG_DSCC4_PCI_RST
1008/*
1009 * Some DSCC4-based cards wires the GPIO port and the PCI #RST pin together
1010 * so as to provide a safe way to reset the asic while not the whole machine
1011 * rebooting.
1012 *
1013 * This code doesn't need to be efficient. Keep It Simple
1014 */
1015static void dscc4_pci_reset(struct pci_dev *pdev, void __iomem *ioaddr)
1016{
1017	int i;
1018
1019	mutex_lock(&dscc4_mutex);
1020	for (i = 0; i < 16; i++)
1021		pci_read_config_dword(pdev, i << 2, dscc4_pci_config_store + i);
1022
1023	/* Maximal LBI clock divider (who cares ?) and whole GPIO range. */
1024	writel(0x001c0000, ioaddr + GMODE);
1025	/* Configure GPIO port as output */
1026	writel(0x0000ffff, ioaddr + GPDIR);
1027	/* Disable interruption */
1028	writel(0x0000ffff, ioaddr + GPIM);
1029
1030	writel(0x0000ffff, ioaddr + GPDATA);
1031	writel(0x00000000, ioaddr + GPDATA);
1032
1033	/* Flush posted writes */
1034	readl(ioaddr + GSTAR);
1035
1036	schedule_timeout_uninterruptible(msecs_to_jiffies(100));
1037
1038	for (i = 0; i < 16; i++)
1039		pci_write_config_dword(pdev, i << 2, dscc4_pci_config_store[i]);
1040	mutex_unlock(&dscc4_mutex);
1041}
1042#else
1043#define dscc4_pci_reset(pdev,ioaddr)	do {} while (0)
1044#endif /* CONFIG_DSCC4_PCI_RST */
1045
1046static int dscc4_open(struct net_device *dev)
1047{
1048	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1049	int ret = -EAGAIN;
1050
1051	if ((dscc4_loopback_check(dpriv) < 0))
1052		goto err;
1053
1054	if ((ret = hdlc_open(dev)))
1055		goto err;
1056
1057	/*
1058	 * Due to various bugs, there is no way to reliably reset a
1059	 * specific port (manufacturer's dependent special PCI #RST wiring
1060	 * apart: it affects all ports). Thus the device goes in the best
1061	 * silent mode possible at dscc4_close() time and simply claims to
1062	 * be up if it's opened again. It still isn't possible to change
1063	 * the HDLC configuration without rebooting but at least the ports
1064	 * can be up/down ifconfig'ed without killing the host.
1065	 */
1066	if (dpriv->flags & FakeReset) {
1067		dpriv->flags &= ~FakeReset;
1068		scc_patchl(0, PowerUp, dpriv, dev, CCR0);
1069		scc_patchl(0, 0x00050000, dpriv, dev, CCR2);
1070		scc_writel(EventsMask, dpriv, dev, IMR);
1071		netdev_info(dev, "up again\n");
1072		goto done;
1073	}
1074
1075	/* IDT+IDR during XPR */
1076	dpriv->flags = NeedIDR | NeedIDT;
1077
1078	scc_patchl(0, PowerUp | Vis, dpriv, dev, CCR0);
1079
1080	/*
1081	 * The following is a bit paranoid...
1082	 *
1083	 * NB: the datasheet "...CEC will stay active if the SCC is in
1084	 * power-down mode or..." and CCR2.RAC = 1 are two different
1085	 * situations.
1086	 */
1087	if (scc_readl_star(dpriv, dev) & SccBusy) {
1088		netdev_err(dev, "busy - try later\n");
1089		ret = -EAGAIN;
1090		goto err_out;
1091	} else
1092		netdev_info(dev, "available - good\n");
1093
1094	scc_writel(EventsMask, dpriv, dev, IMR);
1095
1096	/* Posted write is flushed in the wait_ack loop */
1097	scc_writel(TxSccRes | RxSccRes, dpriv, dev, CMDR);
1098
1099	if ((ret = dscc4_wait_ack_cec(dpriv, dev, "Cec")) < 0)
1100		goto err_disable_scc_events;
1101
1102	/*
1103	 * I would expect XPR near CE completion (before ? after ?).
1104	 * At worst, this code won't see a late XPR and people
1105	 * will have to re-issue an ifconfig (this is harmless).
1106	 * WARNING, a really missing XPR usually means a hardware
1107	 * reset is needed. Suggestions anyone ?
1108	 */
1109	if ((ret = dscc4_xpr_ack(dpriv)) < 0) {
1110		pr_err("XPR timeout\n");
1111		goto err_disable_scc_events;
1112	}
1113	
1114	if (debug > 2)
1115		dscc4_tx_print(dev, dpriv, "Open");
1116
1117done:
1118	netif_start_queue(dev);
1119
1120        init_timer(&dpriv->timer);
1121        dpriv->timer.expires = jiffies + 10*HZ;
1122        dpriv->timer.data = (unsigned long)dev;
1123	dpriv->timer.function = dscc4_timer;
1124        add_timer(&dpriv->timer);
1125	netif_carrier_on(dev);
1126
1127	return 0;
1128
1129err_disable_scc_events:
1130	scc_writel(0xffffffff, dpriv, dev, IMR);
1131	scc_patchl(PowerUp | Vis, 0, dpriv, dev, CCR0);
1132err_out:
1133	hdlc_close(dev);
1134err:
1135	return ret;
1136}
1137
1138#ifdef DSCC4_POLLING
1139static int dscc4_tx_poll(struct dscc4_dev_priv *dpriv, struct net_device *dev)
1140{
1141	/* FIXME: it's gonna be easy (TM), for sure */
1142}
1143#endif /* DSCC4_POLLING */
1144
1145static netdev_tx_t dscc4_start_xmit(struct sk_buff *skb,
1146					  struct net_device *dev)
1147{
1148	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1149	struct dscc4_pci_priv *ppriv = dpriv->pci_priv;
1150	struct TxFD *tx_fd;
1151	int next;
1152
1153	next = dpriv->tx_current%TX_RING_SIZE;
1154	dpriv->tx_skbuff[next] = skb;
1155	tx_fd = dpriv->tx_fd + next;
1156	tx_fd->state = FrameEnd | TO_STATE_TX(skb->len);
1157	tx_fd->data = cpu_to_le32(pci_map_single(ppriv->pdev, skb->data, skb->len,
1158				     PCI_DMA_TODEVICE));
1159	tx_fd->complete = 0x00000000;
1160	tx_fd->jiffies = jiffies;
1161	mb();
1162
1163#ifdef DSCC4_POLLING
1164	spin_lock(&dpriv->lock);
1165	while (dscc4_tx_poll(dpriv, dev));
1166	spin_unlock(&dpriv->lock);
1167#endif
1168
1169	if (debug > 2)
1170		dscc4_tx_print(dev, dpriv, "Xmit");
1171	/* To be cleaned(unsigned int)/optimized. Later, ok ? */
1172	if (!((++dpriv->tx_current - dpriv->tx_dirty)%TX_RING_SIZE))
1173		netif_stop_queue(dev);
1174
1175	if (dscc4_tx_quiescent(dpriv, dev))
1176		dscc4_do_tx(dpriv, dev);
1177
1178	return NETDEV_TX_OK;
1179}
1180
1181static int dscc4_close(struct net_device *dev)
1182{
1183	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1184
1185	del_timer_sync(&dpriv->timer);
1186	netif_stop_queue(dev);
1187
1188	scc_patchl(PowerUp | Vis, 0, dpriv, dev, CCR0);
1189	scc_patchl(0x00050000, 0, dpriv, dev, CCR2);
1190	scc_writel(0xffffffff, dpriv, dev, IMR);
1191
1192	dpriv->flags |= FakeReset;
1193
1194	hdlc_close(dev);
1195
1196	return 0;
1197}
1198
1199static inline int dscc4_check_clock_ability(int port)
1200{
1201	int ret = 0;
1202
1203#ifdef CONFIG_DSCC4_PCISYNC
1204	if (port >= 2)
1205		ret = -1;
1206#endif
1207	return ret;
1208}
1209
1210/*
1211 * DS1 p.137: "There are a total of 13 different clocking modes..."
1212 *                                  ^^
1213 * Design choices:
1214 * - by default, assume a clock is provided on pin RxClk/TxClk (clock mode 0a).
1215 *   Clock mode 3b _should_ work but the testing seems to make this point
1216 *   dubious (DIY testing requires setting CCR0 at 0x00000033).
1217 *   This is supposed to provide least surprise "DTE like" behavior.
1218 * - if line rate is specified, clocks are assumed to be locally generated.
1219 *   A quartz must be available (on pin XTAL1). Modes 6b/7b are used. Choosing
1220 *   between these it automagically done according on the required frequency
1221 *   scaling. Of course some rounding may take place.
1222 * - no high speed mode (40Mb/s). May be trivial to do but I don't have an
1223 *   appropriate external clocking device for testing.
1224 * - no time-slot/clock mode 5: shameless laziness.
1225 *
1226 * The clock signals wiring can be (is ?) manufacturer dependent. Good luck.
1227 *
1228 * BIG FAT WARNING: if the device isn't provided enough clocking signal, it
1229 * won't pass the init sequence. For example, straight back-to-back DTE without
1230 * external clock will fail when dscc4_open() (<- 'ifconfig hdlcx xxx') is
1231 * called.
1232 *
1233 * Typos lurk in datasheet (missing divier in clock mode 7a figure 51 p.153
1234 * DS0 for example)
1235 *
1236 * Clock mode related bits of CCR0:
1237 *     +------------ TOE: output TxClk (0b/2b/3a/3b/6b/7a/7b only)
1238 *     | +---------- SSEL: sub-mode select 0 -> a, 1 -> b
1239 *     | | +-------- High Speed: say 0
1240 *     | | | +-+-+-- Clock Mode: 0..7
1241 *     | | | | | |
1242 * -+-+-+-+-+-+-+-+
1243 * x|x|5|4|3|2|1|0| lower bits
1244 *
1245 * Division factor of BRR: k = (N+1)x2^M (total divider = 16xk in mode 6b)
1246 *            +-+-+-+------------------ M (0..15)
1247 *            | | | |     +-+-+-+-+-+-- N (0..63)
1248 *    0 0 0 0 | | | | 0 0 | | | | | |
1249 * ...-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1250 *    f|e|d|c|b|a|9|8|7|6|5|4|3|2|1|0| lower bits
1251 *
1252 */
1253static int dscc4_set_clock(struct net_device *dev, u32 *bps, u32 *state)
1254{
1255	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1256	int ret = -1;
1257	u32 brr;
1258
1259	*state &= ~Ccr0ClockMask;
1260	if (*bps) { /* Clock generated - required for DCE */
1261		u32 n = 0, m = 0, divider;
1262		int xtal;
1263
1264		xtal = dpriv->pci_priv->xtal_hz;
1265		if (!xtal)
1266			goto done;
1267		if (dscc4_check_clock_ability(dpriv->dev_id) < 0)
1268			goto done;
1269		divider = xtal / *bps;
1270		if (divider > BRR_DIVIDER_MAX) {
1271			divider >>= 4;
1272			*state |= 0x00000036; /* Clock mode 6b (BRG/16) */
1273		} else
1274			*state |= 0x00000037; /* Clock mode 7b (BRG) */
1275		if (divider >> 22) {
1276			n = 63;
1277			m = 15;
1278		} else if (divider) {
1279			/* Extraction of the 6 highest weighted bits */
1280			m = 0;
1281			while (0xffffffc0 & divider) {
1282				m++;
1283				divider >>= 1;
1284			}
1285			n = divider;
1286		}
1287		brr = (m << 8) | n;
1288		divider = n << m;
1289		if (!(*state & 0x00000001)) /* ?b mode mask => clock mode 6b */
1290			divider <<= 4;
1291		*bps = xtal / divider;
1292	} else {
1293		/*
1294		 * External clock - DTE
1295		 * "state" already reflects Clock mode 0a (CCR0 = 0xzzzzzz00).
1296		 * Nothing more to be done
1297		 */
1298		brr = 0;
1299	}
1300	scc_writel(brr, dpriv, dev, BRR);
1301	ret = 0;
1302done:
1303	return ret;
1304}
1305
1306static int dscc4_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1307{
1308	sync_serial_settings __user *line = ifr->ifr_settings.ifs_ifsu.sync;
1309	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1310	const size_t size = sizeof(dpriv->settings);
1311	int ret = 0;
1312
1313        if (dev->flags & IFF_UP)
1314                return -EBUSY;
1315
1316	if (cmd != SIOCWANDEV)
1317		return -EOPNOTSUPP;
1318
1319	switch(ifr->ifr_settings.type) {
1320	case IF_GET_IFACE:
1321		ifr->ifr_settings.type = IF_IFACE_SYNC_SERIAL;
1322		if (ifr->ifr_settings.size < size) {
1323			ifr->ifr_settings.size = size; /* data size wanted */
1324			return -ENOBUFS;
1325		}
1326		if (copy_to_user(line, &dpriv->settings, size))
1327			return -EFAULT;
1328		break;
1329
1330	case IF_IFACE_SYNC_SERIAL:
1331		if (!capable(CAP_NET_ADMIN))
1332			return -EPERM;
1333
1334		if (dpriv->flags & FakeReset) {
1335			netdev_info(dev, "please reset the device before this command\n");
1336			return -EPERM;
1337		}
1338		if (copy_from_user(&dpriv->settings, line, size))
1339			return -EFAULT;
1340		ret = dscc4_set_iface(dpriv, dev);
1341		break;
1342
1343	default:
1344		ret = hdlc_ioctl(dev, ifr, cmd);
1345		break;
1346	}
1347
1348	return ret;
1349}
1350
1351static int dscc4_match(const struct thingie *p, int value)
1352{
1353	int i;
1354
1355	for (i = 0; p[i].define != -1; i++) {
1356		if (value == p[i].define)
1357			break;
1358	}
1359	if (p[i].define == -1)
1360		return -1;
1361	else
1362		return i;
1363}
1364
1365static int dscc4_clock_setting(struct dscc4_dev_priv *dpriv,
1366			       struct net_device *dev)
1367{
1368	sync_serial_settings *settings = &dpriv->settings;
1369	int ret = -EOPNOTSUPP;
1370	u32 bps, state;
1371
1372	bps = settings->clock_rate;
1373	state = scc_readl(dpriv, CCR0);
1374	if (dscc4_set_clock(dev, &bps, &state) < 0)
1375		goto done;
1376	if (bps) { /* DCE */
1377		printk(KERN_DEBUG "%s: generated RxClk (DCE)\n", dev->name);
1378		if (settings->clock_rate != bps) {
1379			printk(KERN_DEBUG "%s: clock adjusted (%08d -> %08d)\n",
1380				dev->name, settings->clock_rate, bps);
1381			settings->clock_rate = bps;
1382		}
1383	} else { /* DTE */
1384		state |= PowerUp | Vis;
1385		printk(KERN_DEBUG "%s: external RxClk (DTE)\n", dev->name);
1386	}
1387	scc_writel(state, dpriv, dev, CCR0);
1388	ret = 0;
1389done:
1390	return ret;
1391}
1392
1393static int dscc4_encoding_setting(struct dscc4_dev_priv *dpriv,
1394				  struct net_device *dev)
1395{
1396	static const struct thingie encoding[] = {
1397		{ ENCODING_NRZ,		0x00000000 },
1398		{ ENCODING_NRZI,	0x00200000 },
1399		{ ENCODING_FM_MARK,	0x00400000 },
1400		{ ENCODING_FM_SPACE,	0x00500000 },
1401		{ ENCODING_MANCHESTER,	0x00600000 },
1402		{ -1,			0}
1403	};
1404	int i, ret = 0;
1405
1406	i = dscc4_match(encoding, dpriv->encoding);
1407	if (i >= 0)
1408		scc_patchl(EncodingMask, encoding[i].bits, dpriv, dev, CCR0);
1409	else
1410		ret = -EOPNOTSUPP;
1411	return ret;
1412}
1413
1414static int dscc4_loopback_setting(struct dscc4_dev_priv *dpriv,
1415				  struct net_device *dev)
1416{
1417	sync_serial_settings *settings = &dpriv->settings;
1418	u32 state;
1419
1420	state = scc_readl(dpriv, CCR1);
1421	if (settings->loopback) {
1422		printk(KERN_DEBUG "%s: loopback\n", dev->name);
1423		state |= 0x00000100;
1424	} else {
1425		printk(KERN_DEBUG "%s: normal\n", dev->name);
1426		state &= ~0x00000100;
1427	}
1428	scc_writel(state, dpriv, dev, CCR1);
1429	return 0;
1430}
1431
1432static int dscc4_crc_setting(struct dscc4_dev_priv *dpriv,
1433			     struct net_device *dev)
1434{
1435	static const struct thingie crc[] = {
1436		{ PARITY_CRC16_PR0_CCITT,	0x00000010 },
1437		{ PARITY_CRC16_PR1_CCITT,	0x00000000 },
1438		{ PARITY_CRC32_PR0_CCITT,	0x00000011 },
1439		{ PARITY_CRC32_PR1_CCITT,	0x00000001 }
1440	};
1441	int i, ret = 0;
1442
1443	i = dscc4_match(crc, dpriv->parity);
1444	if (i >= 0)
1445		scc_patchl(CrcMask, crc[i].bits, dpriv, dev, CCR1);
1446	else
1447		ret = -EOPNOTSUPP;
1448	return ret;
1449}
1450
1451static int dscc4_set_iface(struct dscc4_dev_priv *dpriv, struct net_device *dev)
1452{
1453	struct {
1454		int (*action)(struct dscc4_dev_priv *, struct net_device *);
1455	} *p, do_setting[] = {
1456		{ dscc4_encoding_setting },
1457		{ dscc4_clock_setting },
1458		{ dscc4_loopback_setting },
1459		{ dscc4_crc_setting },
1460		{ NULL }
1461	};
1462	int ret = 0;
1463
1464	for (p = do_setting; p->action; p++) {
1465		if ((ret = p->action(dpriv, dev)) < 0)
1466			break;
1467	}
1468	return ret;
1469}
1470
1471static irqreturn_t dscc4_irq(int irq, void *token)
1472{
1473	struct dscc4_dev_priv *root = token;
1474	struct dscc4_pci_priv *priv;
1475	struct net_device *dev;
1476	void __iomem *ioaddr;
1477	u32 state;
1478	unsigned long flags;
1479	int i, handled = 1;
1480
1481	priv = root->pci_priv;
1482	dev = dscc4_to_dev(root);
1483
1484	spin_lock_irqsave(&priv->lock, flags);
1485
1486	ioaddr = root->base_addr;
1487
1488	state = readl(ioaddr + GSTAR);
1489	if (!state) {
1490		handled = 0;
1491		goto out;
1492	}
1493	if (debug > 3)
1494		printk(KERN_DEBUG "%s: GSTAR = 0x%08x\n", DRV_NAME, state);
1495	writel(state, ioaddr + GSTAR);
1496
1497	if (state & Arf) {
1498		netdev_err(dev, "failure (Arf). Harass the maintainer\n");
1499		goto out;
1500	}
1501	state &= ~ArAck;
1502	if (state & Cfg) {
1503		if (debug > 0)
1504			printk(KERN_DEBUG "%s: CfgIV\n", DRV_NAME);
1505		if (priv->iqcfg[priv->cfg_cur++%IRQ_RING_SIZE] & cpu_to_le32(Arf))
1506			netdev_err(dev, "CFG failed\n");
1507		if (!(state &= ~Cfg))
1508			goto out;
1509	}
1510	if (state & RxEvt) {
1511		i = dev_per_card - 1;
1512		do {
1513			dscc4_rx_irq(priv, root + i);
1514		} while (--i >= 0);
1515		state &= ~RxEvt;
1516	}
1517	if (state & TxEvt) {
1518		i = dev_per_card - 1;
1519		do {
1520			dscc4_tx_irq(priv, root + i);
1521		} while (--i >= 0);
1522		state &= ~TxEvt;
1523	}
1524out:
1525	spin_unlock_irqrestore(&priv->lock, flags);
1526	return IRQ_RETVAL(handled);
1527}
1528
1529static void dscc4_tx_irq(struct dscc4_pci_priv *ppriv,
1530				struct dscc4_dev_priv *dpriv)
1531{
1532	struct net_device *dev = dscc4_to_dev(dpriv);
1533	u32 state;
1534	int cur, loop = 0;
1535
1536try:
1537	cur = dpriv->iqtx_current%IRQ_RING_SIZE;
1538	state = le32_to_cpu(dpriv->iqtx[cur]);
1539	if (!state) {
1540		if (debug > 4)
1541			printk(KERN_DEBUG "%s: Tx ISR = 0x%08x\n", dev->name,
1542			       state);
1543		if ((debug > 1) && (loop > 1))
1544			printk(KERN_DEBUG "%s: Tx irq loop=%d\n", dev->name, loop);
1545		if (loop && netif_queue_stopped(dev))
1546			if ((dpriv->tx_current - dpriv->tx_dirty)%TX_RING_SIZE)
1547				netif_wake_queue(dev);
1548
1549		if (netif_running(dev) && dscc4_tx_quiescent(dpriv, dev) &&
1550		    !dscc4_tx_done(dpriv))
1551				dscc4_do_tx(dpriv, dev);
1552		return;
1553	}
1554	loop++;
1555	dpriv->iqtx[cur] = 0;
1556	dpriv->iqtx_current++;
1557
1558	if (state_check(state, dpriv, dev, "Tx") < 0)
1559		return;
1560
1561	if (state & SccEvt) {
1562		if (state & Alls) {
1563			struct sk_buff *skb;
1564			struct TxFD *tx_fd;
1565
1566			if (debug > 2)
1567				dscc4_tx_print(dev, dpriv, "Alls");
1568			/*
1569			 * DataComplete can't be trusted for Tx completion.
1570			 * Cf errata DS5 p.8
1571			 */
1572			cur = dpriv->tx_dirty%TX_RING_SIZE;
1573			tx_fd = dpriv->tx_fd + cur;
1574			skb = dpriv->tx_skbuff[cur];
1575			if (skb) {
1576				pci_unmap_single(ppriv->pdev, le32_to_cpu(tx_fd->data),
1577						 skb->len, PCI_DMA_TODEVICE);
1578				if (tx_fd->state & FrameEnd) {
1579					dev->stats.tx_packets++;
1580					dev->stats.tx_bytes += skb->len;
1581				}
1582				dev_kfree_skb_irq(skb);
1583				dpriv->tx_skbuff[cur] = NULL;
1584				++dpriv->tx_dirty;
1585			} else {
1586				if (debug > 1)
1587					netdev_err(dev, "Tx: NULL skb %d\n",
1588						   cur);
1589			}
1590			/*
1591			 * If the driver ends sending crap on the wire, it
1592			 * will be way easier to diagnose than the (not so)
1593			 * random freeze induced by null sized tx frames.
1594			 */
1595			tx_fd->data = tx_fd->next;
1596			tx_fd->state = FrameEnd | TO_STATE_TX(2*DUMMY_SKB_SIZE);
1597			tx_fd->complete = 0x00000000;
1598			tx_fd->jiffies = 0;
1599
1600			if (!(state &= ~Alls))
1601				goto try;
1602		}
1603		/*
1604		 * Transmit Data Underrun
1605		 */
1606		if (state & Xdu) {
1607			netdev_err(dev, "Tx Data Underrun. Ask maintainer\n");
1608			dpriv->flags = NeedIDT;
1609			/* Tx reset */
1610			writel(MTFi | Rdt,
1611			       dpriv->base_addr + 0x0c*dpriv->dev_id + CH0CFG);
1612			writel(Action, dpriv->base_addr + GCMDR);
1613			return;
1614		}
1615		if (state & Cts) {
1616			netdev_info(dev, "CTS transition\n");
1617			if (!(state &= ~Cts)) /* DEBUG */
1618				goto try;
1619		}
1620		if (state & Xmr) {
1621			/* Frame needs to be sent again - FIXME */
1622			netdev_err(dev, "Tx ReTx. Ask maintainer\n");
1623			if (!(state &= ~Xmr)) /* DEBUG */
1624				goto try;
1625		}
1626		if (state & Xpr) {
1627			void __iomem *scc_addr;
1628			unsigned long ring;
1629			unsigned int i;
1630
1631			/*
1632			 * - the busy condition happens (sometimes);
1633			 * - it doesn't seem to make the handler unreliable.
1634			 */
1635			for (i = 1; i; i <<= 1) {
1636				if (!(scc_readl_star(dpriv, dev) & SccBusy))
1637					break;
1638			}
1639			if (!i)
1640				netdev_info(dev, "busy in irq\n");
1641
1642			scc_addr = dpriv->base_addr + 0x0c*dpriv->dev_id;
1643			/* Keep this order: IDT before IDR */
1644			if (dpriv->flags & NeedIDT) {
1645				if (debug > 2)
1646					dscc4_tx_print(dev, dpriv, "Xpr");
1647				ring = dpriv->tx_fd_dma +
1648				       (dpriv->tx_dirty%TX_RING_SIZE)*
1649				       sizeof(struct TxFD);
1650				writel(ring, scc_addr + CH0BTDA);
1651				dscc4_do_tx(dpriv, dev);
1652				writel(MTFi | Idt, scc_addr + CH0CFG);
1653				if (dscc4_do_action(dev, "IDT") < 0)
1654					goto err_xpr;
1655				dpriv->flags &= ~NeedIDT;
1656			}
1657			if (dpriv->flags & NeedIDR) {
1658				ring = dpriv->rx_fd_dma +
1659				       (dpriv->rx_current%RX_RING_SIZE)*
1660				       sizeof(struct RxFD);
1661				writel(ring, scc_addr + CH0BRDA);
1662				dscc4_rx_update(dpriv, dev);
1663				writel(MTFi | Idr, scc_addr + CH0CFG);
1664				if (dscc4_do_action(dev, "IDR") < 0)
1665					goto err_xpr;
1666				dpriv->flags &= ~NeedIDR;
1667				smp_wmb();
1668				/* Activate receiver and misc */
1669				scc_writel(0x08050008, dpriv, dev, CCR2);
1670			}
1671		err_xpr:
1672			if (!(state &= ~Xpr))
1673				goto try;
1674		}
1675		if (state & Cd) {
1676			if (debug > 0)
1677				netdev_info(dev, "CD transition\n");
1678			if (!(state &= ~Cd)) /* DEBUG */
1679				goto try;
1680		}
1681	} else { /* ! SccEvt */
1682		if (state & Hi) {
1683#ifdef DSCC4_POLLING
1684			while (!dscc4_tx_poll(dpriv, dev));
1685#endif
1686			netdev_info(dev, "Tx Hi\n");
1687			state &= ~Hi;
1688		}
1689		if (state & Err) {
1690			netdev_info(dev, "Tx ERR\n");
1691			dev->stats.tx_errors++;
1692			state &= ~Err;
1693		}
1694	}
1695	goto try;
1696}
1697
1698static void dscc4_rx_irq(struct dscc4_pci_priv *priv,
1699				    struct dscc4_dev_priv *dpriv)
1700{
1701	struct net_device *dev = dscc4_to_dev(dpriv);
1702	u32 state;
1703	int cur;
1704
1705try:
1706	cur = dpriv->iqrx_current%IRQ_RING_SIZE;
1707	state = le32_to_cpu(dpriv->iqrx[cur]);
1708	if (!state)
1709		return;
1710	dpriv->iqrx[cur] = 0;
1711	dpriv->iqrx_current++;
1712
1713	if (state_check(state, dpriv, dev, "Rx") < 0)
1714		return;
1715
1716	if (!(state & SccEvt)){
1717		struct RxFD *rx_fd;
1718
1719		if (debug > 4)
1720			printk(KERN_DEBUG "%s: Rx ISR = 0x%08x\n", dev->name,
1721			       state);
1722		state &= 0x00ffffff;
1723		if (state & Err) { /* Hold or reset */
1724			printk(KERN_DEBUG "%s: Rx ERR\n", dev->name);
1725			cur = dpriv->rx_current%RX_RING_SIZE;
1726			rx_fd = dpriv->rx_fd + cur;
1727			/*
1728			 * Presume we're not facing a DMAC receiver reset.
1729			 * As We use the rx size-filtering feature of the
1730			 * DSCC4, the beginning of a new frame is waiting in
1731			 * the rx fifo. I bet a Receive Data Overflow will
1732			 * happen most of time but let's try and avoid it.
1733			 * Btw (as for RDO) if one experiences ERR whereas
1734			 * the system looks rather idle, there may be a
1735			 * problem with latency. In this case, increasing
1736			 * RX_RING_SIZE may help.
1737			 */
1738			//while (dpriv->rx_needs_refill) {
1739				while (!(rx_fd->state1 & Hold)) {
1740					rx_fd++;
1741					cur++;
1742					if (!(cur = cur%RX_RING_SIZE))
1743						rx_fd = dpriv->rx_fd;
1744				}
1745				//dpriv->rx_needs_refill--;
1746				try_get_rx_skb(dpriv, dev);
1747				if (!rx_fd->data)
1748					goto try;
1749				rx_fd->state1 &= ~Hold;
1750				rx_fd->state2 = 0x00000000;
1751				rx_fd->end = cpu_to_le32(0xbabeface);
1752			//}
1753			goto try;
1754		}
1755		if (state & Fi) {
1756			dscc4_rx_skb(dpriv, dev);
1757			goto try;
1758		}
1759		if (state & Hi ) { /* HI bit */
1760			netdev_info(dev, "Rx Hi\n");
1761			state &= ~Hi;
1762			goto try;
1763		}
1764	} else { /* SccEvt */
1765		if (debug > 1) {
1766			//FIXME: verifier la presence de tous les evenements
1767		static struct {
1768			u32 mask;
1769			const char *irq_name;
1770		} evts[] = {
1771			{ 0x00008000, "TIN"},
1772			{ 0x00000020, "RSC"},
1773			{ 0x00000010, "PCE"},
1774			{ 0x00000008, "PLLA"},
1775			{ 0, NULL}
1776		}, *evt;
1777
1778		for (evt = evts; evt->irq_name; evt++) {
1779			if (state & evt->mask) {
1780					printk(KERN_DEBUG "%s: %s\n",
1781						dev->name, evt->irq_name);
1782				if (!(state &= ~evt->mask))
1783					goto try;
1784			}
1785		}
1786		} else {
1787			if (!(state &= ~0x0000c03c))
1788				goto try;
1789		}
1790		if (state & Cts) {
1791			netdev_info(dev, "CTS transition\n");
1792			if (!(state &= ~Cts)) /* DEBUG */
1793				goto try;
1794		}
1795		/*
1796		 * Receive Data Overflow (FIXME: fscked)
1797		 */
1798		if (state & Rdo) {
1799			struct RxFD *rx_fd;
1800			void __iomem *scc_addr;
1801			int cur;
1802
1803			//if (debug)
1804			//	dscc4_rx_dump(dpriv);
1805			scc_addr = dpriv->base_addr + 0x0c*dpriv->dev_id;
1806
1807			scc_patchl(RxActivate, 0, dpriv, dev, CCR2);
1808			/*
1809			 * This has no effect. Why ?
1810			 * ORed with TxSccRes, one sees the CFG ack (for
1811			 * the TX part only).
1812			 */
1813			scc_writel(RxSccRes, dpriv, dev, CMDR);
1814			dpriv->flags |= RdoSet;
1815
1816			/*
1817			 * Let's try and save something in the received data.
1818			 * rx_current must be incremented at least once to
1819			 * avoid HOLD in the BRDA-to-be-pointed desc.
1820			 */
1821			do {
1822				cur = dpriv->rx_current++%RX_RING_SIZE;
1823				rx_fd = dpriv->rx_fd + cur;
1824				if (!(rx_fd->state2 & DataComplete))
1825					break;
1826				if (rx_fd->state2 & FrameAborted) {
1827					dev->stats.rx_over_errors++;
1828					rx_fd->state1 |= Hold;
1829					rx_fd->state2 = 0x00000000;
1830					rx_fd->end = cpu_to_le32(0xbabeface);
1831				} else
1832					dscc4_rx_skb(dpriv, dev);
1833			} while (1);
1834
1835			if (debug > 0) {
1836				if (dpriv->flags & RdoSet)
1837					printk(KERN_DEBUG
1838					       "%s: no RDO in Rx data\n", DRV_NAME);
1839			}
1840#ifdef DSCC4_RDO_EXPERIMENTAL_RECOVERY
1841			/*
1842			 * FIXME: must the reset be this violent ?
1843			 */
1844#warning "FIXME: CH0BRDA"
1845			writel(dpriv->rx_fd_dma +
1846			       (dpriv->rx_current%RX_RING_SIZE)*
1847			       sizeof(struct RxFD), scc_addr + CH0BRDA);
1848			writel(MTFi|Rdr|Idr, scc_addr + CH0CFG);
1849			if (dscc4_do_action(dev, "RDR") < 0) {
1850				netdev_err(dev, "RDO recovery failed(RDR)\n");
1851				goto rdo_end;
1852			}
1853			writel(MTFi|Idr, scc_addr + CH0CFG);
1854			if (dscc4_do_action(dev, "IDR") < 0) {
1855				netdev_err(dev, "RDO recovery failed(IDR)\n");
1856				goto rdo_end;
1857			}
1858		rdo_end:
1859#endif
1860			scc_patchl(0, RxActivate, dpriv, dev, CCR2);
1861			goto try;
1862		}
1863		if (state & Cd) {
1864			netdev_info(dev, "CD transition\n");
1865			if (!(state &= ~Cd)) /* DEBUG */
1866				goto try;
1867		}
1868		if (state & Flex) {
1869			printk(KERN_DEBUG "%s: Flex. Ttttt...\n", DRV_NAME);
1870			if (!(state &= ~Flex))
1871				goto try;
1872		}
1873	}
1874}
1875
1876/*
1877 * I had expected the following to work for the first descriptor
1878 * (tx_fd->state = 0xc0000000)
1879 * - Hold=1 (don't try and branch to the next descripto);
1880 * - No=0 (I want an empty data section, i.e. size=0);
1881 * - Fe=1 (required by No=0 or we got an Err irq and must reset).
1882 * It failed and locked solid. Thus the introduction of a dummy skb.
1883 * Problem is acknowledged in errata sheet DS5. Joy :o/
1884 */
1885static struct sk_buff *dscc4_init_dummy_skb(struct dscc4_dev_priv *dpriv)
1886{
1887	struct sk_buff *skb;
1888
1889	skb = dev_alloc_skb(DUMMY_SKB_SIZE);
1890	if (skb) {
1891		int last = dpriv->tx_dirty%TX_RING_SIZE;
1892		struct TxFD *tx_fd = dpriv->tx_fd + last;
1893
1894		skb->len = DUMMY_SKB_SIZE;
1895		skb_copy_to_linear_data(skb, version,
1896					strlen(version) % DUMMY_SKB_SIZE);
1897		tx_fd->state = FrameEnd | TO_STATE_TX(DUMMY_SKB_SIZE);
1898		tx_fd->data = cpu_to_le32(pci_map_single(dpriv->pci_priv->pdev,
1899					     skb->data, DUMMY_SKB_SIZE,
1900					     PCI_DMA_TODEVICE));
1901		dpriv->tx_skbuff[last] = skb;
1902	}
1903	return skb;
1904}
1905
1906static int dscc4_init_ring(struct net_device *dev)
1907{
1908	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
1909	struct pci_dev *pdev = dpriv->pci_priv->pdev;
1910	struct TxFD *tx_fd;
1911	struct RxFD *rx_fd;
1912	void *ring;
1913	int i;
1914
1915	ring = pci_alloc_consistent(pdev, RX_TOTAL_SIZE, &dpriv->rx_fd_dma);
1916	if (!ring)
1917		goto err_out;
1918	dpriv->rx_fd = rx_fd = (struct RxFD *) ring;
1919
1920	ring = pci_alloc_consistent(pdev, TX_TOTAL_SIZE, &dpriv->tx_fd_dma);
1921	if (!ring)
1922		goto err_free_dma_rx;
1923	dpriv->tx_fd = tx_fd = (struct TxFD *) ring;
1924
1925	memset(dpriv->tx_skbuff, 0, sizeof(struct sk_buff *)*TX_RING_SIZE);
1926	dpriv->tx_dirty = 0xffffffff;
1927	i = dpriv->tx_current = 0;
1928	do {
1929		tx_fd->state = FrameEnd | TO_STATE_TX(2*DUMMY_SKB_SIZE);
1930		tx_fd->complete = 0x00000000;
1931	        /* FIXME: NULL should be ok - to be tried */
1932	        tx_fd->data = cpu_to_le32(dpriv->tx_fd_dma);
1933		(tx_fd++)->next = cpu_to_le32(dpriv->tx_fd_dma +
1934					(++i%TX_RING_SIZE)*sizeof(*tx_fd));
1935	} while (i < TX_RING_SIZE);
1936
1937	if (!dscc4_init_dummy_skb(dpriv))
1938		goto err_free_dma_tx;
1939
1940	memset(dpriv->rx_skbuff, 0, sizeof(struct sk_buff *)*RX_RING_SIZE);
1941	i = dpriv->rx_dirty = dpriv->rx_current = 0;
1942	do {
1943		/* size set by the host. Multiple of 4 bytes please */
1944	        rx_fd->state1 = HiDesc;
1945	        rx_fd->state2 = 0x00000000;
1946	        rx_fd->end = cpu_to_le32(0xbabeface);
1947	        rx_fd->state1 |= TO_STATE_RX(HDLC_MAX_MRU);
1948		// FIXME: return value verifiee mais traitement suspect
1949		if (try_get_rx_skb(dpriv, dev) >= 0)
1950			dpriv->rx_dirty++;
1951		(rx_fd++)->next = cpu_to_le32(dpriv->rx_fd_dma +
1952					(++i%RX_RING_SIZE)*sizeof(*rx_fd));
1953	} while (i < RX_RING_SIZE);
1954
1955	return 0;
1956
1957err_free_dma_tx:
1958	pci_free_consistent(pdev, TX_TOTAL_SIZE, ring, dpriv->tx_fd_dma);
1959err_free_dma_rx:
1960	pci_free_consistent(pdev, RX_TOTAL_SIZE, rx_fd, dpriv->rx_fd_dma);
1961err_out:
1962	return -ENOMEM;
1963}
1964
1965static void dscc4_remove_one(struct pci_dev *pdev)
1966{
1967	struct dscc4_pci_priv *ppriv;
1968	struct dscc4_dev_priv *root;
1969	void __iomem *ioaddr;
1970	int i;
1971
1972	ppriv = pci_get_drvdata(pdev);
1973	root = ppriv->root;
1974
1975	ioaddr = root->base_addr;
1976
1977	dscc4_pci_reset(pdev, ioaddr);
1978
1979	free_irq(pdev->irq, root);
1980	pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32), ppriv->iqcfg,
1981			    ppriv->iqcfg_dma);
1982	for (i = 0; i < dev_per_card; i++) {
1983		struct dscc4_dev_priv *dpriv = root + i;
1984
1985		dscc4_release_ring(dpriv);
1986		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
1987				    dpriv->iqrx, dpriv->iqrx_dma);
1988		pci_free_consistent(pdev, IRQ_RING_SIZE*sizeof(u32),
1989				    dpriv->iqtx, dpriv->iqtx_dma);
1990	}
1991
1992	dscc4_free1(pdev);
1993
1994	iounmap(ioaddr);
1995
1996	pci_release_region(pdev, 1);
1997	pci_release_region(pdev, 0);
1998
1999	pci_disable_device(pdev);
2000}
2001
2002static int dscc4_hdlc_attach(struct net_device *dev, unsigned short encoding,
2003	unsigned short parity)
2004{
2005	struct dscc4_dev_priv *dpriv = dscc4_priv(dev);
2006
2007	if (encoding != ENCODING_NRZ &&
2008	    encoding != ENCODING_NRZI &&
2009	    encoding != ENCODING_FM_MARK &&
2010	    encoding != ENCODING_FM_SPACE &&
2011	    encoding != ENCODING_MANCHESTER)
2012		return -EINVAL;
2013
2014	if (parity != PARITY_NONE &&
2015	    parity != PARITY_CRC16_PR0_CCITT &&
2016	    parity != PARITY_CRC16_PR1_CCITT &&
2017	    parity != PARITY_CRC32_PR0_CCITT &&
2018	    parity != PARITY_CRC32_PR1_CCITT)
2019		return -EINVAL;
2020
2021        dpriv->encoding = encoding;
2022        dpriv->parity = parity;
2023	return 0;
2024}
2025
2026#ifndef MODULE
2027static int __init dscc4_setup(char *str)
2028{
2029	int *args[] = { &debug, &quartz, NULL }, **p = args;
2030
2031	while (*p && (get_option(&str, *p) == 2))
2032		p++;
2033	return 1;
2034}
2035
2036__setup("dscc4.setup=", dscc4_setup);
2037#endif
2038
2039static const struct pci_device_id dscc4_pci_tbl[] = {
2040	{ PCI_VENDOR_ID_SIEMENS, PCI_DEVICE_ID_SIEMENS_DSCC4,
2041	        PCI_ANY_ID, PCI_ANY_ID, },
2042	{ 0,}
2043};
2044MODULE_DEVICE_TABLE(pci, dscc4_pci_tbl);
2045
2046static struct pci_driver dscc4_driver = {
2047	.name		= DRV_NAME,
2048	.id_table	= dscc4_pci_tbl,
2049	.probe		= dscc4_init_one,
2050	.remove		= dscc4_remove_one,
2051};
2052
2053module_pci_driver(dscc4_driver);