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