ns820.c

Linux下各种网卡的驱动程序

/* ns820.c: A Linux Gigabit Ethernet driver for the NatSemi DP83820 series. */
/*
	Written/copyright 1999-2003 by Donald Becker.
	Copyright 2002-2003 by Scyld Computing Corporation.

	This software may be used and distributed according to the terms of
	the GNU General Public License (GPL), incorporated herein by reference.
	Drivers based on or derived from this code fall under the GPL and must
	retain the authorship, copyright and license notice.  This file is not
	a complete program and may only be used when the entire operating
	system is licensed under the GPL.  License for under other terms may be
	available.  Contact the original author for details.

	The original author may be reached as [e-mail], or at
	Scyld Computing Corporation
	914 Bay Ridge Road, Suite 220
	Annapolis MD 21403

	Support information and updates available at
		http://www.scyld.com/network/natsemi.html
	The information and support mailing lists are based at
		http://www.scyld.com/mailman/listinfo/
*/

/* These identify the driver base version and may not be removed. */
static const char version1[] =
"ns820.c:v1.03b 12/03/2003  Written by Donald Becker <[e-mail]>\n";
static const char version2[] =
"  http://www.scyld.com/network/natsemi.html\n";
/* Updated to recommendations in pci-skeleton v2.13. */

/* Automatically extracted configuration info:
probe-func: ns820_probe
config-in: tristate 'National Semiconductor DP8382x series PCI Ethernet support' CONFIG_NATSEMI820

c-help-name: National Semiconductor DP8382x series PCI Ethernet support
c-help-symbol: CONFIG_NATSEMI820
c-help: This driver is for the National Semiconductor DP83820 Gigabit Ethernet
c-help: adapter series.
c-help: More specific information and updates are available from
c-help: http://www.scyld.com/network/natsemi.html
*/

/* The user-configurable values.
   These may be modified when a driver module is loaded.*/

/* Message enable level: 0..31 = no..all messages.  See NETIF_MSG docs. */
static int debug = 2;

/* Maximum events (Rx packets, etc.) to handle at each interrupt. */
static int max_interrupt_work = 20;

/* Maximum number of multicast addresses to filter (vs. rx-all-multicast).
   This chip uses a 2048 element hash table based on the Ethernet CRC.
   Previous natsemi chips had unreliable multicast filter circuitry.
   To work around an observed problem set this value to '0',
   which will immediately switch to Rx-all-multicast.
  */
static int multicast_filter_limit = 100;

/* Set the copy breakpoint for the copy-only-tiny-frames scheme.
   Setting to > 1518 effectively disables this feature.
   This chip can only receive into aligned buffers, so architectures such
   as the Alpha AXP might benefit from a copy-align.
*/
static int rx_copybreak = 0;

/* Used to pass the media type, etc.
   Both 'options[]' and 'full_duplex[]' should exist for driver
   interoperability, however setting full_duplex[] is deprecated.
   The media type is usually passed in 'options[]'.
    The default is autonegotation for speed and duplex.
	This should rarely be overridden.
    Use option values 0x10/0x20 for 10Mbps, 0x100,0x200 for 100Mbps.
    Use option values 0x10 and 0x100 for forcing half duplex fixed speed.
    Use option values 0x20 and 0x200 for forcing full duplex operation.
	Use 0x1000 or 0x2000 for gigabit.
*/
#define MAX_UNITS 8		/* More are supported, limit only on options */
static int options[MAX_UNITS] = {-1, -1, -1, -1, -1, -1, -1, -1};
static int full_duplex[MAX_UNITS] = {-1, -1, -1, -1, -1, -1, -1, -1};

/* Operational parameters that are set at compile time. */

/* Keep the ring sizes a power of two for compile efficiency.
   Understand the implications before changing these settings!
   The compiler will convert <unsigned>'%'<2^N> into a bit mask.
   Making the Tx ring too large decreases the effectiveness of channel
   bonding and packet priority, confuses the system network buffer limits,
   and wastes memory.
   Too-large receive rings waste memory and confound network buffer limits.
*/
#define TX_RING_SIZE	16
#define TX_QUEUE_LEN	10		/* Limit ring entries actually used, min 4. */
#define RX_RING_SIZE	64

/* Operational parameters that usually are not changed. */
/* Time in jiffies before concluding the transmitter is hung.
   Re-autonegotiation may take up to 3 seconds.
 */
#define TX_TIMEOUT  (6*HZ)

/* Allocation size of Rx buffers with normal sized Ethernet frames.
   Do not change this value without good reason.  This is not a limit,
   but a way to keep a consistent allocation size among drivers.
 */
#define PKT_BUF_SZ		1536

#ifndef __KERNEL__
#define __KERNEL__
#endif
#if !defined(__OPTIMIZE__)
#warning  You must compile this file with the correct options!
#warning  See the last lines of the source file.
#error You must compile this driver with "-O".
#endif

/* Include files, designed to support most kernel versions 2.0.0 and later. */
#include <linux/config.h>
#if defined(CONFIG_SMP) && ! defined(__SMP__)
#define __SMP__
#endif
#if defined(MODULE) && defined(CONFIG_MODVERSIONS) && ! defined(MODVERSIONS)
#define MODVERSIONS
#endif

#include <linux/version.h>
#if defined(MODVERSIONS)
#include <linux/modversions.h>
#endif
#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#if LINUX_VERSION_CODE >= 0x20400
#include <linux/slab.h>
#else
#include <linux/malloc.h>
#endif
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <asm/processor.h>		/* Processor type for cache alignment. */
#include <asm/bitops.h>
#include <asm/io.h>

#ifdef INLINE_PCISCAN
#include "k_compat.h"
#else
#include "pci-scan.h"
#include "kern_compat.h"
#endif

#if (LINUX_VERSION_CODE >= 0x20100)  &&  defined(MODULE)
char kernel_version[] = UTS_RELEASE;
#endif

MODULE_AUTHOR("Donald Becker <[e-mail]>");
MODULE_DESCRIPTION("National Semiconductor DP83820 series PCI Ethernet driver");
MODULE_LICENSE("GPL");
MODULE_PARM(debug, "i");
MODULE_PARM(options, "1-" __MODULE_STRING(MAX_UNITS) "i");
MODULE_PARM(max_interrupt_work, "i");
MODULE_PARM(full_duplex, "1-" __MODULE_STRING(MAX_UNITS) "i");
MODULE_PARM(rx_copybreak, "i");
MODULE_PARM(multicast_filter_limit, "i");
MODULE_PARM_DESC(debug, "Driver message level (0-31)");
MODULE_PARM_DESC(options, "Force transceiver type or fixed speed+duplex");
MODULE_PARM_DESC(max_interrupt_work,
				 "Driver maximum events handled per interrupt");
MODULE_PARM_DESC(full_duplex,
				 "Non-zero to force full duplex, non-negotiated link "
				 "(deprecated).");
MODULE_PARM_DESC(rx_copybreak,
				 "Breakpoint in bytes for copy-only-tiny-frames");
MODULE_PARM_DESC(multicast_filter_limit,
				 "Multicast addresses before switching to Rx-all-multicast");

/*
				Theory of Operation

I. Board Compatibility

This driver is designed for National Semiconductor DP83820 10/100/1000
Ethernet NIC.  It is superficially similar to the 810 series "natsemi.c"
driver, however the register layout, descriptor layout and element
length of the new chip series is different.

II. Board-specific settings

This driver requires the PCI interrupt line to be configured.
It honors the EEPROM-set values.

III. Driver operation

IIIa. Ring buffers

This driver uses two statically allocated fixed-size descriptor lists
formed into rings by a branch from the final descriptor to the beginning of
the list.  The ring sizes are set at compile time by RX/TX_RING_SIZE.
The NatSemi design uses a 'next descriptor' pointer that the driver forms
into a list, thus rings can be arbitrarily sized.  Before changing the
ring sizes you should understand the flow and cache effects of the
full/available/empty hysteresis.

IIIb/c. Transmit/Receive Structure

This driver uses a zero-copy receive and transmit scheme.
The driver allocates full frame size skbuffs for the Rx ring buffers at
open() time and passes the skb->data field to the chip as receive data
buffers.  When an incoming frame is less than RX_COPYBREAK bytes long,
a fresh skbuff is allocated and the frame is copied to the new skbuff.
When the incoming frame is larger, the skbuff is passed directly up the
protocol stack.  Buffers consumed this way are replaced by newly allocated
skbuffs in a later phase of receives.

The RX_COPYBREAK value is chosen to trade-off the memory wasted by
using a full-sized skbuff for small frames vs. the copying costs of larger
frames.  New boards are typically used in generously configured machines
and the underfilled buffers have negligible impact compared to the benefit of
a single allocation size, so the default value of zero results in never
copying packets.  When copying is done, the cost is usually mitigated by using
a combined copy/checksum routine.  Copying also preloads the cache, which is
most useful with small frames.

A subtle aspect of the operation is that unaligned buffers are not permitted
by the hardware.  Thus the IP header at offset 14 in an ethernet frame isn't
longword aligned for further processing.  On copies frames are put into the
skbuff at an offset of "+2", 16-byte aligning the IP header.

IIId. Synchronization

The driver runs as two independent, single-threaded flows of control.  One
is the send-packet routine, which enforces single-threaded use by the
dev->tbusy flag.  The other thread is the interrupt handler, which is single
threaded by the hardware and interrupt handling software.

The send packet thread has partial control over the Tx ring and 'dev->tbusy'
flag.  It sets the tbusy flag whenever it's queuing a Tx packet. If the next
queue slot is empty, it clears the tbusy flag when finished otherwise it sets
the 'lp->tx_full' flag.

The interrupt handler has exclusive control over the Rx ring and records stats
from the Tx ring.  After reaping the stats, it marks the Tx queue entry as
empty by incrementing the dirty_tx mark. Iff the 'lp->tx_full' flag is set, it
clears both the tx_full and tbusy flags.

IV. Notes

The NatSemi 820 series PCI gigabit chips are very common on low-cost NICs.
The '821 appears to be the same as '820 chip, only with pins for the upper
32 bits marked "N/C".

IVb. References

http://www.scyld.com/expert/100mbps.html
http://www.scyld.com/expert/NWay.html
The NatSemi dp83820 datasheet is available: search www.natsemi.com

IVc. Errata

None characterised.

*/



static void *ns820_probe1(struct pci_dev *pdev, void *init_dev,
							long ioaddr, int irq, int chip_idx, int find_cnt);
static int power_event(void *dev_instance, int event);
enum chip_capability_flags {FDXActiveLow=1, InvertGbXcvrPwr=2, };
#ifdef USE_IO_OPS
#define PCI_IOTYPE (PCI_USES_MASTER | PCI_USES_IO  | PCI_ADDR0)
#else
#define PCI_IOTYPE (PCI_USES_MASTER | PCI_USES_MEM | PCI_ADDR1)
#endif

static struct pci_id_info pci_id_tbl[] = {
	{ "D-Link DGE-500T (DP83820)",
	  { 0x0022100B, 0xffffffff, 0x49001186, 0xffffffff, },
	  PCI_IOTYPE, 256, FDXActiveLow},
	{"NatSemi DP83820", { 0x0022100B, 0xffffffff },
	 PCI_IOTYPE, 256, 0},
	{0,},						/* 0 terminated list. */
};

struct drv_id_info natsemi_drv_id = {
	"ns820", PCI_HOTSWAP, PCI_CLASS_NETWORK_ETHERNET<<8, pci_id_tbl,
	ns820_probe1, power_event };

/* Offsets to the device registers.
   Unlike software-only systems, device drivers interact with complex hardware.
   It's not useful to define symbolic names for every register bit in the
   device.  Please do not change these names without good reason.
*/
enum register_offsets {
	ChipCmd=0x00, ChipConfig=0x04, EECtrl=0x08, PCIBusCfg=0x0C,
	IntrStatus=0x10, IntrMask=0x14, IntrEnable=0x18, IntrHoldoff=0x1C,
	TxRingPtr=0x20, TxRingPtrHi=0x24, TxConfig=0x28,
	RxRingPtr=0x30, RxRingPtrHi=0x34, RxConfig=0x38,
	WOLCmd=0x40, PauseCmd=0x44, RxFilterAddr=0x48, RxFilterData=0x4C,
	BootRomAddr=0x50, BootRomData=0x54, ChipRevReg=0x58,
	StatsCtrl=0x5C, RxPktErrs=0x60, RxMissed=0x68, RxCRCErrs=0x64,
};

/* Bits in ChipCmd. */
enum ChipCmdBits {
	ChipReset=0x100, SoftIntr=0x80, RxReset=0x20, TxReset=0x10,
	RxOff=0x08, RxOn=0x04, TxOff=0x02, TxOn=0x01,
};

/* Bits in ChipConfig. */
enum ChipConfigBits {
	CfgLinkGood=0x80000000, CfgFDX=0x10000000,
	CfgXcrReset=0x0400, CfgXcrOff=0x0200,
};

/* Bits in the interrupt status/mask registers. */
enum intr_status_bits {
	IntrRxDone=0x0001, IntrRxIntr=0x0002, IntrRxErr=0x0004, IntrRxEarly=0x0008,
	IntrRxIdle=0x0010, IntrRxOverrun=0x0020,
	IntrTxDone=0x0040, IntrTxIntr=0x0080, IntrTxErr=0x0100,
	IntrTxIdle=0x0200, IntrTxUnderrun=0x0400,
	StatsMax=0x0800, IntrDrv=0x1000, WOLPkt=0x2000, LinkChange=0x4000,
	RxStatusOverrun=0x10000,
	RxResetDone=0x00200000, TxResetDone=0x00400000,
	IntrPCIErr=0x001E0000,
	IntrNormalSummary=0x0251, IntrAbnormalSummary=0xED20,
};

/* Bits in the RxMode register. */
enum rx_mode_bits {
	AcceptErr=0x20, AcceptRunt=0x10,
	AcceptBroadcast=0xC0000000,
	AcceptMulticast=0x00200000, AcceptAllMulticast=0x20000000,
	AcceptAllPhys=0x10000000, AcceptMyPhys=0x08000000,
};

/* The Rx and Tx buffer descriptors. */
/* Note that using only 32 bit fields simplifies conversion to big-endian
   architectures. */
struct netdev_desc {
#if ADDRLEN == 64
	u64 next_desc;
	u64 buf_addr;
#endif
	u32 next_desc;
	u32 buf_addr;
	s32 cmd_status;
	u32 vlan_status;
};

/* Bits in network_desc.status */
enum desc_status_bits {
	DescOwn=0x80000000, DescMore=0x40000000, DescIntr=0x20000000,
	DescNoCRC=0x10000000,
	DescPktOK=0x08000000, RxTooLong=0x00400000,
};

#define PRIV_ALIGN	15	/* Required alignment mask */
struct netdev_private {
	/* Descriptor rings first for alignment. */
	struct netdev_desc rx_ring[RX_RING_SIZE];
	struct netdev_desc tx_ring[TX_RING_SIZE];
	struct net_device *next_module;		/* Link for devices of this type. */
	void *priv_addr;					/* Unaligned address for kfree */
	const char *product_name;
	/* The addresses of receive-in-place skbuffs. */
	struct sk_buff* rx_skbuff[RX_RING_SIZE];
	/* The saved address of a sent-in-place packet/buffer, for later free(). */
	struct sk_buff* tx_skbuff[TX_RING_SIZE];
	struct net_device_stats stats;
	struct timer_list timer;	/* Media monitoring timer. */
	/* Frequently used values: keep some adjacent for cache effect. */
	int msg_level;
	int chip_id, drv_flags;
	struct pci_dev *pci_dev;
	long in_interrupt;			/* Word-long for SMP locks. */
	int max_interrupt_work;
	int intr_enable;
	unsigned int restore_intr_enable:1;	/* Set if temporarily masked.  */
	unsigned int rx_q_empty:1;			/* Set out-of-skbuffs.  */

	struct netdev_desc *rx_head_desc;
	unsigned int cur_rx, dirty_rx;		/* Producer/consumer ring indices */
	unsigned int rx_buf_sz;				/* Based on MTU+slack. */
	int rx_copybreak;

	unsigned int cur_tx, dirty_tx;