net: atm: remove support for Madge Horizon ATM devices

This driver received nothing but automated fixes since git era begun.
Since it's using virt_to_bus it's unlikely to be used on any modern
platform.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 0 insertions, 3370 deletions

diff --git a/drivers/atm/Kconfig b/drivers/atm/Kconfig
index 360c98ad29eb..9c778308722a 100644
--- a/drivers/atm/Kconfig
+++ b/drivers/atm/Kconfig
@@ -234,30 +234,6 @@ config ATM_IDT77252_USE_SUNI
 	depends on ATM_IDT77252
 	default y
 
-config ATM_HORIZON
-	tristate "Madge Horizon [Ultra] (Collage PCI 25 and Collage PCI 155 Client)"
-	depends on PCI && VIRT_TO_BUS
-	help
-	  This is a driver for the Horizon chipset ATM adapter cards once
-	  produced by Madge Networks Ltd. Say Y (or M to compile as a module
-	  named horizon) here if you have one of these cards.
-
-config ATM_HORIZON_DEBUG
-	bool "Enable debugging messages"
-	depends on ATM_HORIZON
-	help
-	  Somewhat useful debugging messages are available. The choice of
-	  messages is controlled by a bitmap.  This may be specified as a
-	  module argument (kernel command line argument as well?), changed
-	  dynamically using an ioctl (not yet) or changed by sending the
-	  string "Dxxxx" to VCI 1023 (where x is a hex digit).  See the file
-	  <file:drivers/atm/horizon.h> for the meanings of the bits in the
-	  mask.
-
-	  When active, these messages can have a significant impact on the
-	  speed of the driver, and the size of your syslog files! When
-	  inactive, they will have only a modest impact on performance.
-
 config ATM_IA
 	tristate "Interphase ATM PCI x575/x525/x531"
 	depends on PCI
diff --git a/drivers/atm/Makefile b/drivers/atm/Makefile
index 7d38fdaddd09..1b6a8ddaf007 100644
--- a/drivers/atm/Makefile
+++ b/drivers/atm/Makefile
@@ -7,7 +7,6 @@ fore_200e-y	:= fore200e.o
 
 obj-$(CONFIG_ATM_ZATM)		+= zatm.o uPD98402.o
 obj-$(CONFIG_ATM_NICSTAR)	+= nicstar.o
-obj-$(CONFIG_ATM_HORIZON)	+= horizon.o
 obj-$(CONFIG_ATM_IA)		+= iphase.o suni.o
 obj-$(CONFIG_ATM_FORE200E)	+= fore_200e.o
 obj-$(CONFIG_ATM_ENI)		+= eni.o suni.o
diff --git a/drivers/atm/horizon.c b/drivers/atm/horizon.c
deleted file mode 100644
index d0e67ec46216..000000000000
--- a/drivers/atm/horizon.c
+++ /dev/null
@@ -1,2853 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
-  Madge Horizon ATM Adapter driver.
-  Copyright (C) 1995-1999  Madge Networks Ltd.
-  
-*/
-
-/*
-  IMPORTANT NOTE: Madge Networks no longer makes the adapters
-  supported by this driver and makes no commitment to maintain it.
-*/
-
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/sched/signal.h>
-#include <linux/mm.h>
-#include <linux/pci.h>
-#include <linux/errno.h>
-#include <linux/atm.h>
-#include <linux/atmdev.h>
-#include <linux/sonet.h>
-#include <linux/skbuff.h>
-#include <linux/time.h>
-#include <linux/delay.h>
-#include <linux/uio.h>
-#include <linux/init.h>
-#include <linux/interrupt.h>
-#include <linux/ioport.h>
-#include <linux/wait.h>
-#include <linux/slab.h>
-
-#include <asm/io.h>
-#include <linux/atomic.h>
-#include <linux/uaccess.h>
-#include <asm/string.h>
-#include <asm/byteorder.h>
-
-#include "horizon.h"
-
-#define maintainer_string "Giuliano Procida at Madge Networks <gprocida@madge.com>"
-#define description_string "Madge ATM Horizon [Ultra] driver"
-#define version_string "1.2.1"
-
-static inline void __init show_version (void) {
-  printk ("%s version %s\n", description_string, version_string);
-}
-
-/*
-  
-  CREDITS
-  
-  Driver and documentation by:
-  
-  Chris Aston        Madge Networks
-  Giuliano Procida   Madge Networks
-  Simon Benham       Madge Networks
-  Simon Johnson      Madge Networks
-  Various Others     Madge Networks
-  
-  Some inspiration taken from other drivers by:
-  
-  Alexandru Cucos    UTBv
-  Kari Mettinen      University of Helsinki
-  Werner Almesberger EPFL LRC
-  
-  Theory of Operation
-  
-  I Hardware, detection, initialisation and shutdown.
-  
-  1. Supported Hardware
-  
-  This driver should handle all variants of the PCI Madge ATM adapters
-  with the Horizon chipset. These are all PCI cards supporting PIO, BM
-  DMA and a form of MMIO (registers only, not internal RAM).
-  
-  The driver is only known to work with SONET and UTP Horizon Ultra
-  cards at 155Mb/s. However, code is in place to deal with both the
-  original Horizon and 25Mb/s operation.
-  
-  There are two revisions of the Horizon ASIC: the original and the
-  Ultra. Details of hardware bugs are in section III.
-  
-  The ASIC version can be distinguished by chip markings but is NOT
-  indicated by the PCI revision (all adapters seem to have PCI rev 1).
-  
-  I believe that:
-  
-  Horizon       => Collage  25 PCI Adapter (UTP and STP)
-  Horizon Ultra => Collage 155 PCI Client (UTP or SONET)
-  Ambassador x  => Collage 155 PCI Server (completely different)
-  
-  Horizon (25Mb/s) is fitted with UTP and STP connectors. It seems to
-  have a Madge B154 plus glue logic serializer. I have also found a
-  really ancient version of this with slightly different glue. It
-  comes with the revision 0 (140-025-01) ASIC.
-  
-  Horizon Ultra (155Mb/s) is fitted with either a Pulse Medialink
-  output (UTP) or an HP HFBR 5205 output (SONET). It has either
-  Madge's SAMBA framer or a SUNI-lite device (early versions). It
-  comes with the revision 1 (140-027-01) ASIC.
-  
-  2. Detection
-  
-  All Horizon-based cards present with the same PCI Vendor and Device
-  IDs. The standard Linux 2.2 PCI API is used to locate any cards and
-  to enable bus-mastering (with appropriate latency).
-  
-  ATM_LAYER_STATUS in the control register distinguishes between the
-  two possible physical layers (25 and 155). It is not clear whether
-  the 155 cards can also operate at 25Mbps. We rely on the fact that a
-  card operates at 155 if and only if it has the newer Horizon Ultra
-  ASIC.
-  
-  For 155 cards the two possible framers are probed for and then set
-  up for loop-timing.
-  
-  3. Initialisation
-  
-  The card is reset and then put into a known state. The physical
-  layer is configured for normal operation at the appropriate speed;
-  in the case of the 155 cards, the framer is initialised with
-  line-based timing; the internal RAM is zeroed and the allocation of
-  buffers for RX and TX is made; the Burnt In Address is read and
-  copied to the ATM ESI; various policy settings for RX (VPI bits,
-  unknown VCs, oam cells) are made. Ideally all policy items should be
-  configurable at module load (if not actually on-demand), however,
-  only the vpi vs vci bit allocation can be specified at insmod.
-  
-  4. Shutdown
-  
-  This is in response to module_cleaup. No VCs are in use and the card
-  should be idle; it is reset.
-  
-  II Driver software (as it should be)
-  
-  0. Traffic Parameters
-  
-  The traffic classes (not an enumeration) are currently: ATM_NONE (no
-  traffic), ATM_UBR, ATM_CBR, ATM_VBR and ATM_ABR, ATM_ANYCLASS
-  (compatible with everything). Together with (perhaps only some of)
-  the following items they make up the traffic specification.
-  
-  struct atm_trafprm {
-    unsigned char traffic_class; traffic class (ATM_UBR, ...)
-    int           max_pcr;       maximum PCR in cells per second
-    int           pcr;           desired PCR in cells per second
-    int           min_pcr;       minimum PCR in cells per second
-    int           max_cdv;       maximum CDV in microseconds
-    int           max_sdu;       maximum SDU in bytes
-  };
-  
-  Note that these denote bandwidth available not bandwidth used; the
-  possibilities according to ATMF are:
-  
-  Real Time (cdv and max CDT given)
-  
-  CBR(pcr)             pcr bandwidth always available
-  rtVBR(pcr,scr,mbs)   scr bandwidth always available, up to pcr at mbs too
-  
-  Non Real Time
-  
-  nrtVBR(pcr,scr,mbs)  scr bandwidth always available, up to pcr at mbs too
-  UBR()
-  ABR(mcr,pcr)         mcr bandwidth always available, up to pcr (depending) too
-  
-  mbs is max burst size (bucket)
-  pcr and scr have associated cdvt values
-  mcr is like scr but has no cdtv
-  cdtv may differ at each hop
-  
-  Some of the above items are qos items (as opposed to traffic
-  parameters). We have nothing to do with qos. All except ABR can have
-  their traffic parameters converted to GCRA parameters. The GCRA may
-  be implemented as a (real-number) leaky bucket. The GCRA can be used
-  in complicated ways by switches and in simpler ways by end-stations.
-  It can be used both to filter incoming cells and shape out-going
-  cells.
-  
-  ATM Linux actually supports:
-  
-  ATM_NONE() (no traffic in this direction)
-  ATM_UBR(max_frame_size)
-  ATM_CBR(max/min_pcr, max_cdv, max_frame_size)
-  
-  0 or ATM_MAX_PCR are used to indicate maximum available PCR
-  
-  A traffic specification consists of the AAL type and separate
-  traffic specifications for either direction. In ATM Linux it is:
-  
-  struct atm_qos {
-  struct atm_trafprm txtp;
-  struct atm_trafprm rxtp;
-  unsigned char aal;
-  };
-  
-  AAL types are:
-  
-  ATM_NO_AAL    AAL not specified
-  ATM_AAL0      "raw" ATM cells
-  ATM_AAL1      AAL1 (CBR)
-  ATM_AAL2      AAL2 (VBR)
-  ATM_AAL34     AAL3/4 (data)
-  ATM_AAL5      AAL5 (data)
-  ATM_SAAL      signaling AAL
-  
-  The Horizon has support for AAL frame types: 0, 3/4 and 5. However,
-  it does not implement AAL 3/4 SAR and it has a different notion of
-  "raw cell" to ATM Linux's (48 bytes vs. 52 bytes) so neither are
-  supported by this driver.
-  
-  The Horizon has limited support for ABR (including UBR), VBR and
-  CBR. Each TX channel has a bucket (containing up to 31 cell units)
-  and two timers (PCR and SCR) associated with it that can be used to
-  govern cell emissions and host notification (in the case of ABR this
-  is presumably so that RM cells may be emitted at appropriate times).
-  The timers may either be disabled or may be set to any of 240 values
-  (determined by the clock crystal, a fixed (?) per-device divider, a
-  configurable divider and a configurable timer preload value).
-  
-  At the moment only UBR and CBR are supported by the driver. VBR will
-  be supported as soon as ATM for Linux supports it. ABR support is
-  very unlikely as RM cell handling is completely up to the driver.
-  
-  1. TX (TX channel setup and TX transfer)
-  
-  The TX half of the driver owns the TX Horizon registers. The TX
-  component in the IRQ handler is the BM completion handler. This can
-  only be entered when tx_busy is true (enforced by hardware). The
-  other TX component can only be entered when tx_busy is false
-  (enforced by driver). So TX is single-threaded.
-  
-  Apart from a minor optimisation to not re-select the last channel,
-  the TX send component works as follows:
-  
-  Atomic test and set tx_busy until we succeed; we should implement
-  some sort of timeout so that tx_busy will never be stuck at true.
-  
-  If no TX channel is set up for this VC we wait for an idle one (if
-  necessary) and set it up.
-  
-  At this point we have a TX channel ready for use. We wait for enough
-  buffers to become available then start a TX transmit (set the TX
-  descriptor, schedule transfer, exit).
-  
-  The IRQ component handles TX completion (stats, free buffer, tx_busy
-  unset, exit). We also re-schedule further transfers for the same
-  frame if needed.
-  
-  TX setup in more detail:
-  
-  TX open is a nop, the relevant information is held in the hrz_vcc
-  (vcc->dev_data) structure and is "cached" on the card.
-  
-  TX close gets the TX lock and clears the channel from the "cache".
-  
-  2. RX (Data Available and RX transfer)
-  
-  The RX half of the driver owns the RX registers. There are two RX
-  components in the IRQ handler: the data available handler deals with
-  fresh data that has arrived on the card, the BM completion handler
-  is very similar to the TX completion handler. The data available
-  handler grabs the rx_lock and it is only released once the data has
-  been discarded or completely transferred to the host. The BM
-  completion handler only runs when the lock is held; the data
-  available handler is locked out over the same period.
-  
-  Data available on the card triggers an interrupt. If the data is not
-  suitable for our existing RX channels or we cannot allocate a buffer
-  it is flushed. Otherwise an RX receive is scheduled. Multiple RX
-  transfers may be scheduled for the same frame.
-  
-  RX setup in more detail:
-  
-  RX open...
-  RX close...
-  
-  III Hardware Bugs
-  
-  0. Byte vs Word addressing of adapter RAM.
-  
-  A design feature; see the .h file (especially the memory map).
-  
-  1. Bus Master Data Transfers (original Horizon only, fixed in Ultra)
-  
-  The host must not start a transmit direction transfer at a
-  non-four-byte boundary in host memory. Instead the host should
-  perform a byte, or a two byte, or one byte followed by two byte
-  transfer in order to start the rest of the transfer on a four byte
-  boundary. RX is OK.
-  
-  Simultaneous transmit and receive direction bus master transfers are
-  not allowed.
-  
-  The simplest solution to these two is to always do PIO (never DMA)
-  in the TX direction on the original Horizon. More complicated
-  solutions are likely to hurt my brain.
-  
-  2. Loss of buffer on close VC
-  
-  When a VC is being closed, the buffer associated with it is not
-  returned to the pool. The host must store the reference to this
-  buffer and when opening a new VC then give it to that new VC.
-  
-  The host intervention currently consists of stacking such a buffer
-  pointer at VC close and checking the stack at VC open.
-  
-  3. Failure to close a VC
-  
-  If a VC is currently receiving a frame then closing the VC may fail
-  and the frame continues to be received.
-  
-  The solution is to make sure any received frames are flushed when
-  ready. This is currently done just before the solution to 2.
-  
-  4. PCI bus (original Horizon only, fixed in Ultra)
-  
-  Reading from the data port prior to initialisation will hang the PCI
-  bus. Just don't do that then! We don't.
-  
-  IV To Do List
-  
-  . Timer code may be broken.
-  
-  . Allow users to specify buffer allocation split for TX and RX.
-  
-  . Deal once and for all with buggy VC close.
-  
-  . Handle interrupted and/or non-blocking operations.
-  
-  . Change some macros to functions and move from .h to .c.
-  
-  . Try to limit the number of TX frames each VC may have queued, in
-    order to reduce the chances of TX buffer exhaustion.
-  
-  . Implement VBR (bucket and timers not understood) and ABR (need to
-    do RM cells manually); also no Linux support for either.
-  
-  . Implement QoS changes on open VCs (involves extracting parts of VC open
-    and close into separate functions and using them to make changes).
-  
-*/
-
-/********** globals **********/
-
-static void do_housekeeping (struct timer_list *t);
-
-static unsigned short debug = 0;
-static unsigned short vpi_bits = 0;
-static int max_tx_size = 9000;
-static int max_rx_size = 9000;
-static unsigned char pci_lat = 0;
-
-/********** access functions **********/
-
-/* Read / Write Horizon registers */
-static inline void wr_regl (const hrz_dev * dev, unsigned char reg, u32 data) {
-  outl (cpu_to_le32 (data), dev->iobase + reg);
-}
-
-static inline u32 rd_regl (const hrz_dev * dev, unsigned char reg) {
-  return le32_to_cpu (inl (dev->iobase + reg));
-}
-
-static inline void wr_regw (const hrz_dev * dev, unsigned char reg, u16 data) {
-  outw (cpu_to_le16 (data), dev->iobase + reg);
-}
-
-static inline u16 rd_regw (const hrz_dev * dev, unsigned char reg) {
-  return le16_to_cpu (inw (dev->iobase + reg));
-}
-
-static inline void wrs_regb (const hrz_dev * dev, unsigned char reg, void * addr, u32 len) {
-  outsb (dev->iobase + reg, addr, len);
-}
-
-static inline void rds_regb (const hrz_dev * dev, unsigned char reg, void * addr, u32 len) {
-  insb (dev->iobase + reg, addr, len);
-}
-
-/* Read / Write to a given address in Horizon buffer memory.
-   Interrupts must be disabled between the address register and data
-   port accesses as these must form an atomic operation. */
-static inline void wr_mem (const hrz_dev * dev, HDW * addr, u32 data) {
-  // wr_regl (dev, MEM_WR_ADDR_REG_OFF, (u32) addr);
-  wr_regl (dev, MEM_WR_ADDR_REG_OFF, (addr - (HDW *) 0) * sizeof(HDW));
-  wr_regl (dev, MEMORY_PORT_OFF, data);
-}
-
-static inline u32 rd_mem (const hrz_dev * dev, HDW * addr) {
-  // wr_regl (dev, MEM_RD_ADDR_REG_OFF, (u32) addr);
-  wr_regl (dev, MEM_RD_ADDR_REG_OFF, (addr - (HDW *) 0) * sizeof(HDW));
-  return rd_regl (dev, MEMORY_PORT_OFF);
-}
-
-static inline void wr_framer (const hrz_dev * dev, u32 addr, u32 data) {
-  wr_regl (dev, MEM_WR_ADDR_REG_OFF, (u32) addr | 0x80000000);
-  wr_regl (dev, MEMORY_PORT_OFF, data);
-}
-
-static inline u32 rd_framer (const hrz_dev * dev, u32 addr) {
-  wr_regl (dev, MEM_RD_ADDR_REG_OFF, (u32) addr | 0x80000000);
-  return rd_regl (dev, MEMORY_PORT_OFF);
-}
-
-/********** specialised access functions **********/
-
-/* RX */
-
-static inline void FLUSH_RX_CHANNEL (hrz_dev * dev, u16 channel) {
-  wr_regw (dev, RX_CHANNEL_PORT_OFF, FLUSH_CHANNEL | channel);
-  return;
-}
-
-static void WAIT_FLUSH_RX_COMPLETE (hrz_dev * dev) {
-  while (rd_regw (dev, RX_CHANNEL_PORT_OFF) & FLUSH_CHANNEL)
-    ;
-  return;
-}
-
-static inline void SELECT_RX_CHANNEL (hrz_dev * dev, u16 channel) {
-  wr_regw (dev, RX_CHANNEL_PORT_OFF, channel);
-  return;
-}
-
-static void WAIT_UPDATE_COMPLETE (hrz_dev * dev) {
-  while (rd_regw (dev, RX_CHANNEL_PORT_OFF) & RX_CHANNEL_UPDATE_IN_PROGRESS)
-    ;
-  return;
-}
-
-/* TX */
-
-static inline void SELECT_TX_CHANNEL (hrz_dev * dev, u16 tx_channel) {
-  wr_regl (dev, TX_CHANNEL_PORT_OFF, tx_channel);
-  return;
-}
-
-/* Update or query one configuration parameter of a particular channel. */
-
-static inline void update_tx_channel_config (hrz_dev * dev, short chan, u8 mode, u16 value) {
-  wr_regw (dev, TX_CHANNEL_CONFIG_COMMAND_OFF,
-	   chan * TX_CHANNEL_CONFIG_MULT | mode);
-    wr_regw (dev, TX_CHANNEL_CONFIG_DATA_OFF, value);
-    return;
-}
-
-/********** dump functions **********/
-
-static inline void dump_skb (char * prefix, unsigned int vc, struct sk_buff * skb) {
-#ifdef DEBUG_HORIZON
-  unsigned int i;
-  unsigned char * data = skb->data;
-  PRINTDB (DBG_DATA, "%s(%u) ", prefix, vc);
-  for (i=0; i<skb->len && i < 256;i++)
-    PRINTDM (DBG_DATA, "%02x ", data[i]);
-  PRINTDE (DBG_DATA,"");
-#else
-  (void) prefix;
-  (void) vc;
-  (void) skb;
-#endif
-  return;
-}
-
-static inline void dump_regs (hrz_dev * dev) {
-#ifdef DEBUG_HORIZON
-  PRINTD (DBG_REGS, "CONTROL 0: %#x", rd_regl (dev, CONTROL_0_REG));
-  PRINTD (DBG_REGS, "RX CONFIG: %#x", rd_regw (dev, RX_CONFIG_OFF));
-  PRINTD (DBG_REGS, "TX CONFIG: %#x", rd_regw (dev, TX_CONFIG_OFF));
-  PRINTD (DBG_REGS, "TX STATUS: %#x", rd_regw (dev, TX_STATUS_OFF));
-  PRINTD (DBG_REGS, "IRQ ENBLE: %#x", rd_regl (dev, INT_ENABLE_REG_OFF));
-  PRINTD (DBG_REGS, "IRQ SORCE: %#x", rd_regl (dev, INT_SOURCE_REG_OFF));
-#else
-  (void) dev;
-#endif
-  return;
-}
-
-static inline void dump_framer (hrz_dev * dev) {
-#ifdef DEBUG_HORIZON
-  unsigned int i;
-  PRINTDB (DBG_REGS, "framer registers:");
-  for (i = 0; i < 0x10; ++i)
-    PRINTDM (DBG_REGS, " %02x", rd_framer (dev, i));
-  PRINTDE (DBG_REGS,"");
-#else
-  (void) dev;
-#endif
-  return;
-}
-
-/********** VPI/VCI <-> (RX) channel conversions **********/
-
-/* RX channels are 10 bit integers, these fns are quite paranoid */
-
-static inline int vpivci_to_channel (u16 * channel, const short vpi, const int vci) {
-  unsigned short vci_bits = 10 - vpi_bits;
-  if (0 <= vpi && vpi < 1<<vpi_bits && 0 <= vci && vci < 1<<vci_bits) {
-    *channel = vpi<<vci_bits | vci;
-    return *channel ? 0 : -EINVAL;
-  }
-  return -EINVAL;
-}
-
-/********** decode RX queue entries **********/
-
-static inline u16 rx_q_entry_to_length (u32 x) {
-  return x & RX_Q_ENTRY_LENGTH_MASK;
-}
-
-static inline u16 rx_q_entry_to_rx_channel (u32 x) {
-  return (x>>RX_Q_ENTRY_CHANNEL_SHIFT) & RX_CHANNEL_MASK;
-}
-
-/* Cell Transmit Rate Values
- *
- * the cell transmit rate (cells per sec) can be set to a variety of
- * different values by specifying two parameters: a timer preload from
- * 1 to 16 (stored as 0 to 15) and a clock divider (2 to the power of
- * an exponent from 0 to 14; the special value 15 disables the timer).
- *
- * cellrate = baserate / (preload * 2^divider)
- *
- * The maximum cell rate that can be specified is therefore just the
- * base rate. Halving the preload is equivalent to adding 1 to the
- * divider and so values 1 to 8 of the preload are redundant except
- * in the case of a maximal divider (14).
- *
- * Given a desired cell rate, an algorithm to determine the preload
- * and divider is:
- * 
- * a) x = baserate / cellrate, want p * 2^d = x (as far as possible)
- * b) if x > 16 * 2^14 then set p = 16, d = 14 (min rate), done
- *    if x <= 16 then set p = x, d = 0 (high rates), done
- * c) now have 16 < x <= 2^18, or 1 < x/16 <= 2^14 and we want to
- *    know n such that 2^(n-1) < x/16 <= 2^n, so slide a bit until
- *    we find the range (n will be between 1 and 14), set d = n
- * d) Also have 8 < x/2^n <= 16, so set p nearest x/2^n
- *
- * The algorithm used below is a minor variant of the above.
- *
- * The base rate is derived from the oscillator frequency (Hz) using a
- * fixed divider:
- *
- * baserate = freq / 32 in the case of some Unknown Card
- * baserate = freq / 8  in the case of the Horizon        25
- * baserate = freq / 8  in the case of the Horizon Ultra 155
- *
- * The Horizon cards have oscillators and base rates as follows:
- *
- * Card               Oscillator  Base Rate
- * Unknown Card       33 MHz      1.03125 MHz (33 MHz = PCI freq)
- * Horizon        25  32 MHz      4       MHz
- * Horizon Ultra 155  40 MHz      5       MHz
- *
- * The following defines give the base rates in Hz. These were
- * previously a factor of 100 larger, no doubt someone was using
- * cps*100.
- */
-
-#define BR_UKN 1031250l
-#define BR_HRZ 4000000l
-#define BR_ULT 5000000l
-
-// d is an exponent
-#define CR_MIND 0
-#define CR_MAXD 14
-
-// p ranges from 1 to a power of 2
-#define CR_MAXPEXP 4
- 
-static int make_rate (const hrz_dev * dev, u32 c, rounding r,
-		      u16 * bits, unsigned int * actual)
-{
-	// note: rounding the rate down means rounding 'p' up
-	const unsigned long br = test_bit(ultra, &dev->flags) ? BR_ULT : BR_HRZ;
-  
-	u32 div = CR_MIND;
-	u32 pre;
-  
-	// br_exp and br_man are used to avoid overflowing (c*maxp*2^d) in
-	// the tests below. We could think harder about exact possibilities
-	// of failure...
-  
-	unsigned long br_man = br;
-	unsigned int br_exp = 0;
-  
-	PRINTD (DBG_QOS|DBG_FLOW, "make_rate b=%lu, c=%u, %s", br, c,
-		r == round_up ? "up" : r == round_down ? "down" : "nearest");
-  
-	// avoid div by zero
-	if (!c) {
-		PRINTD (DBG_QOS|DBG_ERR, "zero rate is not allowed!");
-		return -EINVAL;
-	}
-  
-	while (br_exp < CR_MAXPEXP + CR_MIND && (br_man % 2 == 0)) {
-		br_man = br_man >> 1;
-		++br_exp;
-	}
-	// (br >>br_exp) <<br_exp == br and
-	// br_exp <= CR_MAXPEXP+CR_MIND
-  
-	if (br_man <= (c << (CR_MAXPEXP+CR_MIND-br_exp))) {
-		// Equivalent to: B <= (c << (MAXPEXP+MIND))
-		// take care of rounding
-		switch (r) {
-			case round_down:
-				pre = DIV_ROUND_UP(br, c<<div);
-				// but p must be non-zero
-				if (!pre)
-					pre = 1;
-				break;
-			case round_nearest:
-				pre = DIV_ROUND_CLOSEST(br, c<<div);
-				// but p must be non-zero
-				if (!pre)
-					pre = 1;
-				break;
-			default:	/* round_up */
-				pre = br/(c<<div);
-				// but p must be non-zero
-				if (!pre)
-					return -EINVAL;
-		}
-		PRINTD (DBG_QOS, "A: p=%u, d=%u", pre, div);
-		goto got_it;
-	}
-  
-	// at this point we have
-	// d == MIND and (c << (MAXPEXP+MIND)) < B
-	while (div < CR_MAXD) {
-		div++;
-		if (br_man <= (c << (CR_MAXPEXP+div-br_exp))) {
-			// Equivalent to: B <= (c << (MAXPEXP+d))
-			// c << (MAXPEXP+d-1) < B <= c << (MAXPEXP+d)
-			// 1 << (MAXPEXP-1) < B/2^d/c <= 1 << MAXPEXP
-			// MAXP/2 < B/c2^d <= MAXP
-			// take care of rounding
-			switch (r) {
-				case round_down:
-					pre = DIV_ROUND_UP(br, c<<div);
-					break;
-				case round_nearest:
-					pre = DIV_ROUND_CLOSEST(br, c<<div);
-					break;
-				default: /* round_up */
-					pre = br/(c<<div);
-			}
-			PRINTD (DBG_QOS, "B: p=%u, d=%u", pre, div);
-			goto got_it;
-		}
-	}
-	// at this point we have
-	// d == MAXD and (c << (MAXPEXP+MAXD)) < B
-	// but we cannot go any higher
-	// take care of rounding
-	if (r == round_down)
-		return -EINVAL;
-	pre = 1 << CR_MAXPEXP;
-	PRINTD (DBG_QOS, "C: p=%u, d=%u", pre, div);
-got_it:
-	// paranoia
-	if (div > CR_MAXD || (!pre) || pre > 1<<CR_MAXPEXP) {
-		PRINTD (DBG_QOS, "set_cr internal failure: d=%u p=%u",
-			div, pre);
-		return -EINVAL;
-	} else {
-		if (bits)
-			*bits = (div<<CLOCK_SELECT_SHIFT) | (pre-1);
-		if (actual) {
-			*actual = DIV_ROUND_UP(br, pre<<div);
-			PRINTD (DBG_QOS, "actual rate: %u", *actual);
-		}
-		return 0;
-	}
-}
-
-static int make_rate_with_tolerance (const hrz_dev * dev, u32 c, rounding r, unsigned int tol,
-				     u16 * bit_pattern, unsigned int * actual) {
-  unsigned int my_actual;
-  
-  PRINTD (DBG_QOS|DBG_FLOW, "make_rate_with_tolerance c=%u, %s, tol=%u",
-	  c, (r == round_up) ? "up" : (r == round_down) ? "down" : "nearest", tol);
-  
-  if (!actual)
-    // actual rate is not returned
-    actual = &my_actual;
-  
-  if (make_rate (dev, c, round_nearest, bit_pattern, actual))
-    // should never happen as round_nearest always succeeds
-    return -1;
-  
-  if (c - tol <= *actual && *actual <= c + tol)
-    // within tolerance
-    return 0;
-  else
-    // intolerant, try rounding instead
-    return make_rate (dev, c, r, bit_pattern, actual);
-}
-
-/********** Listen on a VC **********/
-
-static int hrz_open_rx (hrz_dev * dev, u16 channel) {
-  // is there any guarantee that we don't get two simulataneous
-  // identical calls of this function from different processes? yes
-  // rate_lock
-  unsigned long flags;
-  u32 channel_type; // u16?
-  
-  u16 buf_ptr = RX_CHANNEL_IDLE;
-  
-  rx_ch_desc * rx_desc = &memmap->rx_descs[channel];
-  
-  PRINTD (DBG_FLOW, "hrz_open_rx %x", channel);
-  
-  spin_lock_irqsave (&dev->mem_lock, flags);
-  channel_type = rd_mem (dev, &rx_desc->wr_buf_type) & BUFFER_PTR_MASK;
-  spin_unlock_irqrestore (&dev->mem_lock, flags);
-  
-  // very serious error, should never occur
-  if (channel_type != RX_CHANNEL_DISABLED) {
-    PRINTD (DBG_ERR|DBG_VCC, "RX channel for VC already open");
-    return -EBUSY; // clean up?
-  }
-  
-  // Give back spare buffer
-  if (dev->noof_spare_buffers) {
-    buf_ptr = dev->spare_buffers[--dev->noof_spare_buffers];
-    PRINTD (DBG_VCC, "using a spare buffer: %u", buf_ptr);
-    // should never occur
-    if (buf_ptr == RX_CHANNEL_DISABLED || buf_ptr == RX_CHANNEL_IDLE) {
-      // but easy to recover from
-      PRINTD (DBG_ERR|DBG_VCC, "bad spare buffer pointer, using IDLE");
-      buf_ptr = RX_CHANNEL_IDLE;
-    }
-  } else {
-    PRINTD (DBG_VCC, "using IDLE buffer pointer");
-  }
-  
-  // Channel is currently disabled so change its status to idle
-  
-  // do we really need to save the flags again?
-  spin_lock_irqsave (&dev->mem_lock, flags);
-  
-  wr_mem (dev, &rx_desc->wr_buf_type,
-	  buf_ptr | CHANNEL_TYPE_AAL5 | FIRST_CELL_OF_AAL5_FRAME);
-  if (buf_ptr != RX_CHANNEL_IDLE)
-    wr_mem (dev, &rx_desc->rd_buf_type, buf_ptr);
-  
-  spin_unlock_irqrestore (&dev->mem_lock, flags);
-  
-  // rxer->rate = make_rate (qos->peak_cells);
-  
-  PRINTD (DBG_FLOW, "hrz_open_rx ok");
-  
-  return 0;
-}
-
-#if 0
-/********** change vc rate for a given vc **********/
-
-static void hrz_change_vc_qos (ATM_RXER * rxer, MAAL_QOS * qos) {
-  rxer->rate = make_rate (qos->peak_cells);
-}
-#endif
-
-/********** free an skb (as per ATM device driver documentation) **********/
-
-static void hrz_kfree_skb (struct sk_buff * skb) {
-  if (ATM_SKB(skb)->vcc->pop) {
-    ATM_SKB(skb)->vcc->pop (ATM_SKB(skb)->vcc, skb);
-  } else {
-    dev_kfree_skb_any (skb);
-  }
-}
-
-/********** cancel listen on a VC **********/
-
-static void hrz_close_rx (hrz_dev * dev, u16 vc) {
-  unsigned long flags;
-  
-  u32 value;
-  
-  u32 r1, r2;
-  
-  rx_ch_desc * rx_desc = &memmap->rx_descs[vc];
-  
-  int was_idle = 0;
-  
-  spin_lock_irqsave (&dev->mem_lock, flags);
-  value = rd_mem (dev, &rx_desc->wr_buf_type) & BUFFER_PTR_MASK;
-  spin_unlock_irqrestore (&dev->mem_lock, flags);
-  
-  if (value == RX_CHANNEL_DISABLED) {
-    // I suppose this could happen once we deal with _NONE traffic properly
-    PRINTD (DBG_VCC, "closing VC: RX channel %u already disabled", vc);
-    return;
-  }
-  if (value == RX_CHANNEL_IDLE)
-    was_idle = 1;
-  
-  spin_lock_irqsave (&dev->mem_lock, flags);
-  
-  for (;;) {
-    wr_mem (dev, &rx_desc->wr_buf_type, RX_CHANNEL_DISABLED);
-    
-    if ((rd_mem (dev, &rx_desc->wr_buf_type) & BUFFER_PTR_MASK) == RX_CHANNEL_DISABLED)
-      break;
-    
-    was_idle = 0;
-  }
-  
-  if (was_idle) {
-    spin_unlock_irqrestore (&dev->mem_lock, flags);
-    return;
-  }
-  
-  WAIT_FLUSH_RX_COMPLETE(dev);
-  
-  // XXX Is this all really necessary? We can rely on the rx_data_av
-  // handler to discard frames that remain queued for delivery. If the
-  // worry is that immediately reopening the channel (perhaps by a
-  // different process) may cause some data to be mis-delivered then
-  // there may still be a simpler solution (such as busy-waiting on
-  // rx_busy once the channel is disabled or before a new one is
-  // opened - does this leave any holes?). Arguably setting up and
-  // tearing down the TX and RX halves of each virtual circuit could
-  // most safely be done within ?x_busy protected regions.
-  
-  // OK, current changes are that Simon's marker is disabled and we DO
-  // look for NULL rxer elsewhere. The code here seems flush frames
-  // and then remember the last dead cell belonging to the channel
-  // just disabled - the cell gets relinked at the next vc_open.
-  // However, when all VCs are closed or only a few opened there are a
-  // handful of buffers that are unusable.
-  
-  // Does anyone feel like documenting spare_buffers properly?
-  // Does anyone feel like fixing this in a nicer way?
-  
-  // Flush any data which is left in the channel
-  for (;;) {
-    // Change the rx channel port to something different to the RX
-    // channel we are trying to close to force Horizon to flush the rx
-    // channel read and write pointers.
-    
-    u16 other = vc^(RX_CHANS/2);
-    
-    SELECT_RX_CHANNEL (dev, other);
-    WAIT_UPDATE_COMPLETE (dev);
-    
-    r1 = rd_mem (dev, &rx_desc->rd_buf_type);
-    
-    // Select this RX channel. Flush doesn't seem to work unless we
-    // select an RX channel before hand
-    
-    SELECT_RX_CHANNEL (dev, vc);
-    WAIT_UPDATE_COMPLETE (dev);
-    
-    // Attempt to flush a frame on this RX channel
-    
-    FLUSH_RX_CHANNEL (dev, vc);
-    WAIT_FLUSH_RX_COMPLETE (dev);
-    
-    // Force Horizon to flush rx channel read and write pointers as before
-    
-    SELECT_RX_CHANNEL (dev, other);
-    WAIT_UPDATE_COMPLETE (dev);
-    
-    r2 = rd_mem (dev, &rx_desc->rd_buf_type);
-    
-    PRINTD (DBG_VCC|DBG_RX, "r1 = %u, r2 = %u", r1, r2);
-    
-    if (r1 == r2) {
-      dev->spare_buffers[dev->noof_spare_buffers++] = (u16)r1;
-      break;
-    }
-  }
-  
-#if 0
-  {
-    rx_q_entry * wr_ptr = &memmap->rx_q_entries[rd_regw (dev, RX_QUEUE_WR_PTR_OFF)];
-    rx_q_entry * rd_ptr = dev->rx_q_entry;
-    
-    PRINTD (DBG_VCC|DBG_RX, "rd_ptr = %u, wr_ptr = %u", rd_ptr, wr_ptr);
-    
-    while (rd_ptr != wr_ptr) {
-      u32 x = rd_mem (dev, (HDW *) rd_ptr);
-      
-      if (vc == rx_q_entry_to_rx_channel (x)) {
-	x |= SIMONS_DODGEY_MARKER;
-	
-	PRINTD (DBG_RX|DBG_VCC|DBG_WARN, "marking a frame as dodgey");
-	
-	wr_mem (dev, (HDW *) rd_ptr, x);
-      }
-      
-      if (rd_ptr == dev->rx_q_wrap)
-	rd_ptr = dev->rx_q_reset;
-      else
-	rd_ptr++;
-    }
-  }
-#endif
-  
-  spin_unlock_irqrestore (&dev->mem_lock, flags);
-  
-  return;
-}
-
-/********** schedule RX transfers **********/
-
-// Note on tail recursion: a GCC developer said that it is not likely
-// to be fixed soon, so do not define TAILRECUSRIONWORKS unless you
-// are sure it does as you may otherwise overflow the kernel stack.
-
-// giving this fn a return value would help GCC, allegedly
-
-static void rx_schedule (hrz_dev * dev, int irq) {
-  unsigned int rx_bytes;
-  
-  int pio_instead = 0;
-#ifndef TAILRECURSIONWORKS
-  pio_instead = 1;
-  while (pio_instead) {
-#endif
-    // bytes waiting for RX transfer
-    rx_bytes = dev->rx_bytes;
-    
-#if 0
-    spin_count = 0;
-    while (rd_regl (dev, MASTER_RX_COUNT_REG_OFF)) {
-      PRINTD (DBG_RX|DBG_WARN, "RX error: other PCI Bus Master RX still in progress!");
-      if (++spin_count > 10) {
-	PRINTD (DBG_RX|DBG_ERR, "spun out waiting PCI Bus Master RX completion");
-	wr_regl (dev, MASTER_RX_COUNT_REG_OFF, 0);
-	clear_bit (rx_busy, &dev->flags);
-	hrz_kfree_skb (dev->rx_skb);
-	return;
-      }
-    }
-#endif
-