cregit-Linux how code gets into the kernel

Release 4.11 drivers/atm/firestream.c

Directory: drivers/atm
/* drivers/atm/firestream.c - FireStream 155 (MB86697) and
 *                            FireStream  50 (MB86695) device driver 
 */
 
/* Written & (C) 2000 by R.E.Wolff@BitWizard.nl 
 * Copied snippets from zatm.c by Werner Almesberger, EPFL LRC/ICA 
 * and ambassador.c Copyright (C) 1995-1999  Madge Networks Ltd 
 */

/*
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  The GNU GPL is contained in /usr/doc/copyright/GPL on a Debian
  system and in the file COPYING in the Linux kernel source.
*/


#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/pci.h>
#include <linux/poison.h>
#include <linux/errno.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/sonet.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/delay.h>
#include <linux/ioport.h> /* for request_region */
#include <linux/uio.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/capability.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
#include <asm/string.h>
#include <asm/io.h>
#include <linux/atomic.h>
#include <linux/uaccess.h>
#include <linux/wait.h>

#include "firestream.h"


static int loopback = 0;

static int num=0x5a;

/* According to measurements (but they look suspicious to me!) done in
 * '97, 37% of the packets are one cell in size. So it pays to have
 * buffers allocated at that size. A large jump in percentage of
 * packets occurs at packets around 536 bytes in length. So it also
 * pays to have those pre-allocated. Unfortunately, we can't fully
 * take advantage of this as the majority of the packets is likely to
 * be TCP/IP (As where obviously the measurement comes from) There the
 * link would be opened with say a 1500 byte MTU, and we can't handle
 * smaller buffers more efficiently than the larger ones. -- REW
 */

/* Due to the way Linux memory management works, specifying "576" as
 * an allocation size here isn't going to help. They are allocated
 * from 1024-byte regions anyway. With the size of the sk_buffs (quite
 * large), it doesn't pay to allocate the smallest size (64) -- REW */

/* This is all guesswork. Hard numbers to back this up or disprove this, 
 * are appreciated. -- REW */

/* The last entry should be about 64k. However, the "buffer size" is
 * passed to the chip in a 16 bit field. I don't know how "65536"
 * would be interpreted. -- REW */


#define NP FS_NR_FREE_POOLS

static int rx_buf_sizes[NP]  = {128,  256,  512, 1024, 2048, 4096, 16384, 65520};
/* log2:                 7     8     9    10    11    12    14     16 */

#if 0
static int rx_pool_sizes[NP] = {1024, 1024, 512, 256,  128,  64,   32,    32};
#else
/* debug */

static int rx_pool_sizes[NP] = {128,  128,  128, 64,   64,   64,   32,    32};
#endif
/* log2:                 10    10    9    8     7     6     5      5  */
/* sumlog2:              17    18    18   18    18    18    19     21 */
/* mem allocated:        128k  256k  256k 256k  256k  256k  512k   2M */
/* tot mem: almost 4M */

/* NP is shorter, so that it fits on a single line. */

#undef NP


/* Small hardware gotcha:

   The FS50 CAM (VP/VC match registers) always take the lowest channel
   number that matches. This is not a problem.

   However, they also ignore whether the channel is enabled or
   not. This means that if you allocate channel 0 to 1.2 and then
   channel 1 to 0.0, then disabeling channel 0 and writing 0 to the
   match channel for channel 0 will "steal" the traffic from channel
   1, even if you correctly disable channel 0.

   Workaround: 

   - When disabling channels, write an invalid VP/VC value to the
   match register. (We use 0xffffffff, which in the worst case 
   matches VP/VC = <maxVP>/<maxVC>, but I expect it not to match
   anything as some "when not in use, program to 0" bits are now
   programmed to 1...)

   - Don't initialize the match registers to 0, as 0.0 is a valid
   channel.
*/


/* Optimization hints and tips.

   The FireStream chips are very capable of reducing the amount of
   "interrupt-traffic" for the CPU. This driver requests an interrupt on EVERY
   action. You could try to minimize this a bit. 

   Besides that, the userspace->kernel copy and the PCI bus are the
   performance limiting issues for this driver.

   You could queue up a bunch of outgoing packets without telling the
   FireStream. I'm not sure that's going to win you much though. The
   Linux layer won't tell us in advance when it's not going to give us
   any more packets in a while. So this is tricky to implement right without
   introducing extra delays. 
  
   -- REW
 */




/* The strings that define what the RX queue entry is all about. */
/* Fujitsu: Please tell me which ones can have a pointer to a 
   freepool descriptor! */

static char *res_strings[] = {
	"RX OK: streaming not EOP", 
	"RX OK: streaming EOP", 
	"RX OK: Single buffer packet", 
	"RX OK: packet mode", 
	"RX OK: F4 OAM (end to end)", 
	"RX OK: F4 OAM (Segment)", 
	"RX OK: F5 OAM (end to end)", 
	"RX OK: F5 OAM (Segment)", 
	"RX OK: RM cell", 
	"RX OK: TRANSP cell", 
	"RX OK: TRANSPC cell", 
	"Unmatched cell", 
	"reserved 12", 
	"reserved 13", 
	"reserved 14", 
	"Unrecognized cell", 
	"reserved 16", 
	"reassembly abort: AAL5 abort", 
	"packet purged", 
	"packet ageing timeout", 
	"channel ageing timeout", 
	"calculated length error", 
	"programmed length limit error", 
	"aal5 crc32 error", 
	"oam transp or transpc crc10 error", 
	"reserved 25", 
	"reserved 26", 
	"reserved 27", 
	"reserved 28", 
	"reserved 29", 
	"reserved 30", /* FIXME: The strings between 30-40 might be wrong. */
	"reassembly abort: no buffers", 
	"receive buffer overflow", 
	"change in GFC", 
	"receive buffer full", 
	"low priority discard - no receive descriptor", 
	"low priority discard - missing end of packet", 
	"reserved 37",
	"reserved 38",
	"reserved 39",
	"reseverd 40",
	"reserved 41", 
	"reserved 42", 
	"reserved 43", 
	"reserved 44", 
	"reserved 45", 
	"reserved 46", 
	"reserved 47", 
	"reserved 48", 
	"reserved 49", 
	"reserved 50", 
	"reserved 51", 
	"reserved 52", 
	"reserved 53", 
	"reserved 54", 
	"reserved 55", 
	"reserved 56", 
	"reserved 57", 
	"reserved 58", 
	"reserved 59", 
	"reserved 60", 
	"reserved 61", 
	"reserved 62", 
	"reserved 63", 
};  


static char *irq_bitname[] = {
	"LPCO",
	"DPCO",
	"RBRQ0_W",
	"RBRQ1_W",
	"RBRQ2_W",
	"RBRQ3_W",
	"RBRQ0_NF",
	"RBRQ1_NF",
	"RBRQ2_NF",
	"RBRQ3_NF",
	"BFP_SC",
	"INIT",
	"INIT_ERR",
	"USCEO",
	"UPEC0",
	"VPFCO",
	"CRCCO",
	"HECO",
	"TBRQ_W",
	"TBRQ_NF",
	"CTPQ_E",
	"GFC_C0",
	"PCI_FTL",
	"CSQ_W",
	"CSQ_NF",
	"EXT_INT",
	"RXDMA_S"
};



#define PHY_EOF -1

#define PHY_CLEARALL -2


struct reginit_item {
	

int reg, val;
};



static struct reginit_item PHY_NTC_INIT[] = {
	{ PHY_CLEARALL, 0x40 }, 
	{ 0x12,  0x0001 },
	{ 0x13,  0x7605 },
	{ 0x1A,  0x0001 },
	{ 0x1B,  0x0005 },
	{ 0x38,  0x0003 },
	{ 0x39,  0x0006 },   /* changed here to make loopback */
	{ 0x01,  0x5262 },
	{ 0x15,  0x0213 },
	{ 0x00,  0x0003 },
	{ PHY_EOF, 0},    /* -1 signals end of list */
};


/* Safetyfeature: If the card interrupts more than this number of times
   in a jiffy (1/100th of a second) then we just disable the interrupt and
   print a message. This prevents the system from hanging. 

   150000 packets per second is close to the limit a PC is going to have
   anyway. We therefore have to disable this for production. -- REW */

#undef IRQ_RATE_LIMIT 
// 100

/* Interrupts work now. Unlike serial cards, ATM cards don't work all
   that great without interrupts. -- REW */

#undef FS_POLL_FREQ 
// 100

/* 
   This driver can spew a whole lot of debugging output at you. If you
   need maximum performance, you should disable the DEBUG define. To
   aid in debugging in the field, I'm leaving the compile-time debug
   features enabled, and disable them "runtime". That allows me to
   instruct people with problems to enable debugging without requiring
   them to recompile... -- REW
*/

#define DEBUG

#ifdef DEBUG

#define fs_dprintk(f, str...) if (fs_debug & f) printk (str)
#else

#define fs_dprintk(f, str...) 
/* nothing */
#endif



static int fs_keystream = 0;

#ifdef DEBUG
/* I didn't forget to set this to zero before shipping. Hit me with a stick 
   if you get this with the debug default not set to zero again. -- REW */

static int fs_debug = 0;
#else

#define fs_debug 0
#endif

#ifdef MODULE
#ifdef DEBUG 
module_param(fs_debug, int, 0644);
#endif
module_param(loopback, int, 0);
module_param(num, int, 0);
module_param(fs_keystream, int, 0);
/* XXX Add rx_buf_sizes, and rx_pool_sizes As per request Amar. -- REW */
#endif



#define FS_DEBUG_FLOW    0x00000001

#define FS_DEBUG_OPEN    0x00000002

#define FS_DEBUG_QUEUE   0x00000004

#define FS_DEBUG_IRQ     0x00000008

#define FS_DEBUG_INIT    0x00000010

#define FS_DEBUG_SEND    0x00000020

#define FS_DEBUG_PHY     0x00000040

#define FS_DEBUG_CLEANUP 0x00000080

#define FS_DEBUG_QOS     0x00000100

#define FS_DEBUG_TXQ     0x00000200

#define FS_DEBUG_ALLOC   0x00000400

#define FS_DEBUG_TXMEM   0x00000800

#define FS_DEBUG_QSIZE   0x00001000



#define func_enter() fs_dprintk(FS_DEBUG_FLOW, "fs: enter %s\n", __func__)

#define func_exit()  fs_dprintk(FS_DEBUG_FLOW, "fs: exit  %s\n", __func__)



static struct fs_dev *fs_boards = NULL;

#ifdef DEBUG




static void my_hd (void *addr, int len)
{
	int j, ch;
	unsigned char *ptr = addr;

	while (len > 0) {
		printk ("%p ", ptr);
		for (j=0;j < ((len < 16)?len:16);j++) {
			printk ("%02x %s", ptr[j], (j==7)?" ":"");
		}
		for (  ;j < 16;j++) {
			printk ("   %s", (j==7)?" ":"");
		}
		for (j=0;j < ((len < 16)?len:16);j++) {
			ch = ptr[j];
			printk ("%c", (ch < 0x20)?'.':((ch > 0x7f)?'.':ch));
		}
		printk ("\n");
		ptr += 16;
		len -= 16;
	}
}

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#else /* DEBUG */



static void my_hd (void *addr, int len){}

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#endif /* DEBUG */

/********** free an skb (as per ATM device driver documentation) **********/

/* Hmm. If this is ATM specific, why isn't there an ATM routine for this?
 * I copied it over from the ambassador driver. -- REW */




static inline void fs_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);
}





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/* It seems the ATM forum recommends this horribly complicated 16bit
 * floating point format. Turns out the Ambassador uses the exact same
 * encoding. I just copied it over. If Mitch agrees, I'll move it over
 * to the atm_misc file or something like that. (and remove it from 
 * here and the ambassador driver) -- REW
 */

/* The good thing about this format is that it is monotonic. So, 
   a conversion routine need not be very complicated. To be able to
   round "nearest" we need to take along a few extra bits. Lets
   put these after 16 bits, so that we can just return the top 16
   bits of the 32bit number as the result:

   int mr (unsigned int rate, int r) 
     {
     int e = 16+9;
     static int round[4]={0, 0, 0xffff, 0x8000};
     if (!rate) return 0;
     while (rate & 0xfc000000) {
       rate >>= 1;
       e++;
     }
     while (! (rate & 0xfe000000)) {
       rate <<= 1;
       e--;
     }

// Now the mantissa is in positions bit 16-25. Excepf for the "hidden 1" that's in bit 26.
     rate &= ~0x02000000;
// Next add in the exponent
     rate |= e << (16+9);
// And perform the rounding:
     return (rate + round[r]) >> 16;
   }

   14 lines-of-code. Compare that with the 120 that the Ambassador
   guys needed. (would be 8 lines shorter if I'd try to really reduce
   the number of lines:

   int mr (unsigned int rate, int r) 
   {
     int e = 16+9;
     static int round[4]={0, 0, 0xffff, 0x8000};
     if (!rate) return 0;
     for (;  rate & 0xfc000000 ;rate >>= 1, e++);
     for (;!(rate & 0xfe000000);rate <<= 1, e--);
     return ((rate & ~0x02000000) | (e << (16+9)) + round[r]) >> 16;
   }

   Exercise for the reader: Remove one more line-of-code, without
   cheating. (Just joining two lines is cheating). (I know it's
   possible, don't think you've beat me if you found it... If you
   manage to lose two lines or more, keep me updated! ;-)

   -- REW */



#define ROUND_UP      1

#define ROUND_DOWN    2

#define ROUND_NEAREST 3
/********** make rate (not quite as much fun as Horizon) **********/




static int make_rate(unsigned int rate, int r,
		      u16 *bits, unsigned int *actual)
{
	unsigned char exp = -1; /* hush gcc */
	unsigned int man = -1;  /* hush gcc */
  
	fs_dprintk (FS_DEBUG_QOS, "make_rate %u", rate);
  
	/* rates in cells per second, ITU format (nasty 16-bit floating-point)
           given 5-bit e and 9-bit m:
           rate = EITHER (1+m/2^9)*2^e    OR 0
           bits = EITHER 1<<14 | e<<9 | m OR 0
           (bit 15 is "reserved", bit 14 "non-zero")
           smallest rate is 0 (special representation)
           largest rate is (1+511/512)*2^31 = 4290772992 (< 2^32-1)
           smallest non-zero rate is (1+0/512)*2^0 = 1 (> 0)
           simple algorithm:
           find position of top bit, this gives e
           remove top bit and shift (rounding if feeling clever) by 9-e
        */
	/* Ambassador ucode bug: please don't set bit 14! so 0 rate not
           representable. // This should move into the ambassador driver
           when properly merged. -- REW */
  
	if (rate > 0xffc00000U) {
		/* larger than largest representable rate */
    
		if (r == ROUND_UP) {
			return -EINVAL;
		} else {
			exp = 31;
			man = 511;
		}
    
	} else if (rate) {
		/* representable rate */
    
		exp = 31;
		man = rate;
    
		/* invariant: rate = man*2^(exp-31) */
		while (!(man & (1<<31))) {
			exp = exp - 1;
			man = man<<1;
		}
    
		/* man has top bit set
                   rate = (2^31+(man-2^31))*2^(exp-31)
                   rate = (1+(man-2^31)/2^31)*2^exp 
                */
		man = man<<1;
		man &= 0xffffffffU; /* a nop on 32-bit systems */
		/* rate = (1+man/2^32)*2^exp
    
                   exp is in the range 0 to 31, man is in the range 0 to 2^32-1
                   time to lose significance... we want m in the range 0 to 2^9-1
                   rounding presents a minor problem... we first decide which way
                   we are rounding (based on given rounding direction and possibly
                   the bits of the mantissa that are to be discarded).
                */

		switch (r) {
		case ROUND_DOWN: {
			/* just truncate */
			man = man>>(32-9);
			break;
		}
		case ROUND_UP: {
			/* check all bits that we are discarding */
			if (man & (~0U>>9)) {
				man = (man>>(32-9)) + 1;
				if (man == (1<<9)) {
					/* no need to check for round up outside of range */
					man = 0;
					exp += 1;
				}
			} else {
				man = (man>>(32-9));
			}
			break;
		}
		case ROUND_NEAREST: {
			/* check msb that we are discarding */
			if (man & (1<<(32-9-1))) {
				man = (man>>(32-9)) + 1;
				if (man == (1<<9)) {
					/* no need to check for round up outside of range */
					man = 0;
					exp += 1;
				}
			} else {
				man = (man>>(32-9));
			}
			break;
		}
		}
    
	} else {
		/* zero rate - not representable */
    
		if (r == ROUND_DOWN) {
			return -EINVAL;
		} else {
			exp = 0;
			man = 0;
		}
	}
  
	fs_dprintk (FS_DEBUG_QOS, "rate: man=%u, exp=%hu", man, exp);
  
	if (bits)
		*bits = /* (1<<14) | */ (exp<<9) | man;
  
	if (actual)
		*actual = (exp >= 9)
			? (1 << exp) + (man << (exp-9))
			: (1 << exp) + ((man + (1<<(9-exp-1))) >> (9-exp));
  
	return 0;
}





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/* FireStream access routines */
/* For DEEP-DOWN debugging these can be rigged to intercept accesses to
   certain registers or to just log all accesses. */




static inline void write_fs (struct fs_dev *dev, int offset, u32 val)
{
	writel (val, dev->base + offset);
}



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static inline u32  read_fs (struct fs_dev *dev, int offset)
{
	return readl (dev->base + offset);
}




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static inline struct FS_QENTRY *get_qentry (struct fs_dev *dev, struct queue *q)
{
	return bus_to_virt (read_fs (dev, Q_WP(q->offset)) & Q_ADDR_MASK);
}



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static void submit_qentry (struct fs_dev *dev, struct queue *q, struct FS_QENTRY *qe)
{
	u32 wp;
	struct FS_QENTRY *cqe;

	/* XXX Sanity check: the write pointer can be checked to be 
           still the same as the value passed as qe... -- REW */
	/*  udelay (5); */
	while ((wp = read_fs (dev, Q_WP (q->offset))) & Q_FULL) {
		fs_dprintk (FS_DEBUG_TXQ, "Found queue at %x full. Waiting.\n", 
			    q->offset);
		schedule ();
	}

	wp &= ~0xf;
	cqe = bus_to_virt (wp);
	if (qe != cqe) {
		fs_dprintk (FS_DEBUG_TXQ, "q mismatch! %p %p\n", qe, cqe);
	}

	write_fs (dev, Q_WP(q->offset), Q_INCWRAP);

	{
		static int c;
		if (!(c++ % 100))
			{
				int rp, wp;
				rp =  read_fs (dev, Q_RP(q->offset));
				wp =  read_fs (dev, Q_WP(q->offset));
				fs_dprintk (FS_DEBUG_TXQ, "q at %d: %x-%x: %x entries.\n", 
					    q->offset, rp, wp, wp-rp);
			}
	}
}


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#ifdef DEBUG_EXTRA

static struct FS_QENTRY pq[60];

static int qp;


static struct FS_BPENTRY dq[60];

static int qd;

static void *da[60];
#endif 




static void submit_queue (struct fs_dev *dev, struct queue *q, 
			  u32 cmd, u32 p1, u32 p2, u32 p3)
{
	struct FS_QENTRY *qe;

	qe = get_qentry (dev, q);
	qe->cmd = cmd;
	qe->p0 = p1;
	qe->p1 = p2;
	qe->p2 = p3;
	submit_qentry (dev,  q, qe);

#ifdef DEBUG_EXTRA
	pq[qp].cmd = cmd;
	pq[qp].p0 = p1;
	pq[qp].p1 = p2;
	pq[qp].p2 = p3;
	qp++;
	if (qp >= 60) qp = 0;
#endif
}


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/* Test the "other" way one day... -- REW */
#if 1

#define submit_command submit_queue
#else




static void submit_command (struct fs_dev *dev, struct queue *q, 
			    u32 cmd, u32 p1, u32 p2, u32 p3)
{
	write_fs (dev, CMDR0, cmd);
	write_fs (dev, CMDR1, p1);
	write_fs (dev, CMDR2, p2);
	write_fs (dev, CMDR3, p3);
}

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#endif






static void process_return_queue (struct fs_dev *dev, struct queue *q)
{
	long rq;
	struct FS_QENTRY *qe;
	void *tc;
  
	while (!((rq = read_fs (dev, Q_RP(q->offset))) & Q_EMPTY)) {
		fs_dprintk (FS_DEBUG_QUEUE, "reaping return queue entry at %lx\n", rq); 
		qe = bus_to_virt (rq);
    
		fs_dprintk (FS_DEBUG_QUEUE, "queue entry: %08x %08x %08x %08x. (%d)\n", 
			    qe->cmd, qe->p0, qe->p1, qe->p2, STATUS_CODE (qe));

		switch (STATUS_CODE (qe)) {
		case 5:
			tc = bus_to_virt (qe->p0);
			fs_dprintk (FS_DEBUG_ALLOC, "Free tc: %p\n", tc);
			kfree (tc);
			break;
		}
    
		write_fs (dev, Q_RP(q->offset), Q_INCWRAP);
	}
}



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static