sundance.c

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/* sundance.c: A Linux device driver for the Sundance ST201 "Alta". */
/*
	Written 1999-2000 by Donald Becker.

	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.

	The author may be reached as [e-mail], or C/O
	Scyld Computing Corporation
	410 Severn Ave., Suite 210
	Annapolis MD 21403

	Support and updates available at
	http://www.scyld.com/network/sundance.html
*/

/* These identify the driver base version and may not be removed. */
static const char version1[] =
"sundance.c:v1.01 4/09/00  Written by Donald Becker\n";
static const char version2[] =
"  http://www.scyld.com/network/sundance.html\n";

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

static int debug = 1;			/* 1 normal messages, 0 quiet .. 7 verbose. */
/* Maximum events (Rx packets, etc.) to handle at each interrupt. */
static int max_interrupt_work = 20;
static int mtu = 0;
/* Maximum number of multicast addresses to filter (vs. rx-all-multicast).
   Typical is a 64 element hash table based on the Ethernet CRC.  */
static int multicast_filter_limit = 32;

/* Set the copy breakpoint for the copy-only-tiny-frames scheme.
   Setting to > 1518 effectively disables this feature.
   This chip can receive into offset buffers, so the Alpha does not
   need 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.
   The media type is usually passed in 'options[]'.
*/
#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.
   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, and more than 128 requires modifying the
   Tx error recovery.
   Large receive rings merely waste memory. */
#define TX_RING_SIZE	16
#define TX_QUEUE_LEN	10		/* Limit ring entries actually used.  */
#define RX_RING_SIZE	32

/* Operational parameters that usually are not changed. */
/* Time in jiffies before concluding the transmitter is hung. */
#define TX_TIMEOUT  (2*HZ)

#define PKT_BUF_SZ		1536			/* Size of each temporary Rx buffer.*/

#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/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/malloc.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <asm/processor.h>		/* Processor type for cache alignment. */
#include <asm/bitops.h>
#include <asm/io.h>

#include <linux/spinlock.h>


/* Condensed operations for readability. */
#define virt_to_le32desc(addr)  cpu_to_le32(virt_to_bus(addr))
#define le32desc_to_virt(addr)  bus_to_virt(le32_to_cpu(addr))


MODULE_AUTHOR("Donald Becker <[e-mail]>");
MODULE_DESCRIPTION("Sundance Alta Ethernet driver");
MODULE_PARM(max_interrupt_work, "i");
MODULE_PARM(mtu, "i");
MODULE_PARM(debug, "i");
MODULE_PARM(rx_copybreak, "i");
MODULE_PARM(options, "1-" __MODULE_STRING(MAX_UNITS) "i");
MODULE_PARM(full_duplex, "1-" __MODULE_STRING(MAX_UNITS) "i");

/*
				Theory of Operation

I. Board Compatibility

This driver is designed for the Sundance Technologies "Alta" ST201 chip.

II. Board-specific settings

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.
Some chips explicitly use only 2^N sized rings, while others use a
'next descriptor' pointer that the driver forms into rings.

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 the IP header at offset 14 in an
ethernet frame isn't longword aligned for further processing.
Unaligned buffers are permitted by the Sundance hardware, so
frames are received 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

IVb. References

The Sundance ST201 datasheet, preliminary version.
http://cesdis.gsfc.nasa.gov/linux/misc/100mbps.html
http://cesdis.gsfc.nasa.gov/linux/misc/NWay.html

IVc. Errata

*/



enum pci_id_flags_bits {
        /* Set PCI command register bits before calling probe1(). */
        PCI_USES_IO=1, PCI_USES_MEM=2, PCI_USES_MASTER=4,
        /* Read and map the single following PCI BAR. */
        PCI_ADDR0=0<<4, PCI_ADDR1=1<<4, PCI_ADDR2=2<<4, PCI_ADDR3=3<<4,
        PCI_ADDR_64BITS=0x100, PCI_NO_ACPI_WAKE=0x200, PCI_NO_MIN_LATENCY=0x400,
};
enum chip_capability_flags {CanHaveMII=1, };
#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_device_id sundance_pci_tbl[] __devinitdata = {
	{ 0x1186, 0x1002, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
	{ 0x13F0, 0x0201, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 1 },
	{ 0, }
};
MODULE_DEVICE_TABLE(pci, sundance_pci_tbl);

struct pci_id_info {
        const char *name;
        struct match_info {
                int     pci, pci_mask, subsystem, subsystem_mask;
                int revision, revision_mask;                            /* Only 8 bits. */
        } id;
        enum pci_id_flags_bits pci_flags;
        int io_size;                            /* Needed for I/O region check or ioremap(). */
        int drv_flags;                          /* Driver use, intended as capability flags. */
};
static struct pci_id_info pci_id_tbl[] = {
	{"OEM Sundance Technology ST201", {0x10021186, 0xffffffff, },
	 PCI_IOTYPE, 128, CanHaveMII},
	{"Sundance Technology Alta", {0x020113F0, 0xffffffff, },
	 PCI_IOTYPE, 128, CanHaveMII},
	{0,},						/* 0 terminated list. */
};

/* This driver was written to use PCI memory space, however x86-oriented
   hardware often uses I/O space accesses. */
#ifdef USE_IO_OPS
#undef readb
#undef readw
#undef readl
#undef writeb
#undef writew
#undef writel
#define readb inb
#define readw inw
#define readl inl
#define writeb outb
#define writew outw
#define writel outl
#endif

/* 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.  The name can only partially document the semantics and make
   the driver longer and more difficult to read.
   In general, only the important configuration values or bits changed
   multiple times should be defined symbolically.
*/
enum alta_offsets {
	DMACtrl=0x00,     TxListPtr=0x04, TxDMACtrl=0x08, TxDescPoll=0x0a,
	RxDMAStatus=0x0c, RxListPtr=0x10, RxDMACtrl=0x14, RxDescPoll=0x16,
	LEDCtrl=0x1a, ASICCtrl=0x30,
	EEData=0x34, EECtrl=0x36, TxThreshold=0x3c,
	FlashAddr=0x40, FlashData=0x44, TxStatus=0x46, DownCounter=0x48,
	IntrClear=0x4a, IntrEnable=0x4c, IntrStatus=0x4e,
	MACCtrl0=0x50, MACCtrl1=0x52, StationAddr=0x54,
	MaxTxSize=0x5A, RxMode=0x5c, MIICtrl=0x5e,
	MulticastFilter0=0x60, MulticastFilter1=0x64,
	RxOctetsLow=0x68, RxOctetsHigh=0x6a, TxOctetsLow=0x6c, TxOctetsHigh=0x6e,
	TxFramesOK=0x70, RxFramesOK=0x72, StatsCarrierError=0x74,
	StatsLateColl=0x75, StatsMultiColl=0x76, StatsOneColl=0x77,
	StatsTxDefer=0x78, RxMissed=0x79, StatsTxXSDefer=0x7a, StatsTxAbort=0x7b,
	StatsBcastTx=0x7c, StatsBcastRx=0x7d, StatsMcastTx=0x7e, StatsMcastRx=0x7f,
	/* Aliased and bogus values! */
	RxStatus=0x0c,
};

/* Bits in the interrupt status/mask registers. */
enum intr_status_bits {
	IntrSummary=0x0001, IntrPCIErr=0x0002, IntrMACCtrl=0x0008,
	IntrTxDone=0x0004, IntrRxDone=0x0010, IntrRxStart=0x0020,
	IntrDrvRqst=0x0040,
	StatsMax=0x0080, LinkChange=0x0100,
	IntrTxDMADone=0x0200, IntrRxDMADone=0x0400,
};

/* Bits in the RxMode register. */
enum rx_mode_bits {
	AcceptAllIPMulti=0x20, AcceptMultiHash=0x10, AcceptAll=0x08,
	AcceptBroadcast=0x04, AcceptMulticast=0x02, AcceptMyPhys=0x01,
};
/* Bits in MACCtrl. */
enum mac_ctrl0_bits {
	EnbFullDuplex=0x20, EnbRcvLargeFrame=0x40,
	EnbFlowCtrl=0x100, EnbPassRxCRC=0x200,
};
enum mac_ctrl1_bits {
	StatsEnable=0x0020,	StatsDisable=0x0040, StatsEnabled=0x0080,
	TxEnable=0x0100, TxDisable=0x0200, TxEnabled=0x0400,
	RxEnable=0x0800, RxDisable=0x1000, RxEnabled=0x2000,
};

/* The Rx and Tx buffer descriptors. */
/* Note that using only 32 bit fields simplifies conversion to big-endian
   architectures. */
struct netdev_desc {
	u32 next_desc;
	u32 status;
	struct desc_frag { u32 addr, length; } frag[1];
};

/* Bits in netdev_desc.status */
enum desc_status_bits {
	DescOwn=0x8000, DescEndPacket=0x4000, DescEndRing=0x2000,
	LastFrag=0x80000000, DescIntrOnTx=0x8000, DescIntrOnDMADone=0x80000000,
};

#define PRIV_ALIGN	15 	/* Required alignment mask */
/* Use  __attribute__((aligned (L1_CACHE_BYTES)))  to maintain alignment
   within the structure. */
struct netdev_private {
	/* Descriptor rings first for alignment. */
	struct netdev_desc rx_ring[RX_RING_SIZE];
	struct netdev_desc tx_ring[TX_RING_SIZE];
	/* 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. */
	spinlock_t lock;
	int chip_id, drv_flags;
	/* Note: Cache paragraph grouped variables. */
	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. */
	spinlock_t txlock;					/* Group with Tx control cache line. */
	struct netdev_desc *last_tx;		/* Last Tx descriptor used. */
	unsigned int cur_tx, dirty_tx;
	unsigned int tx_full:1;				/* The Tx queue is full. */
	/* These values are keep track of the transceiver/media in use. */
	unsigned int full_duplex:1;			/* Full-duplex operation requested. */
	unsigned int duplex_lock:1;
	unsigned int medialock:1;			/* Do not sense media. */
	unsigned int default_port:4;		/* Last dev->if_port value. */
	/* Multicast and receive mode. */
	spinlock_t mcastlock;				/* SMP lock multicast updates. */
	u16 mcast_filter[4];
	/* MII transceiver section. */
	int mii_cnt;						/* MII device addresses. */
	u16 advertising;					/* NWay media advertisement */
	unsigned char phys[2];				/* MII device addresses. */
};

/* The station address location in the EEPROM. */
#define EEPROM_SA_OFFSET	0x10

static int  eeprom_read(long ioaddr, int location);
static int  mdio_read(struct net_device *dev, int phy_id, int location);
static void mdio_write(struct net_device *dev, int phy_id, int location, int value);
static int  netdev_open(struct net_device *dev);
static void check_duplex(struct net_device *dev);
static void netdev_timer(unsigned long data);
static void tx_timeout(struct net_device *dev);
static void init_ring(struct net_device *dev);
static int  start_tx(struct sk_buff *skb, struct net_device *dev);
static void intr_handler(int irq, void *dev_instance, struct pt_regs *regs);
static void netdev_error(struct net_device *dev, int intr_status);
static int  netdev_rx(struct net_device *dev);
static void netdev_error(struct net_device *dev, int intr_status);
static void set_rx_mode(struct net_device *dev);
static struct net_device_stats *get_stats(struct net_device *dev);
static int mii_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
static int  netdev_close(struct net_device *dev);



static int __devinit sundance_probe1 (struct pci_dev *pdev,
				      const struct pci_device_id *ent)
{
	struct net_device *dev;
	struct netdev_private *np;
	static int card_idx;
	int chip_idx = ent->driver_data;
	int irq = pdev->irq;
	int i, option = card_idx < MAX_UNITS ? options[card_idx] : 0;
	long ioaddr;

	if (pci_enable_device(pdev))
		return -EIO;
	pci_set_master(pdev);

	dev = init_etherdev(NULL, sizeof(*np));
	if (!dev)
		return -ENOMEM;
	SET_MODULE_OWNER(dev);

#ifdef USE_IO_OPS
	ioaddr = pci_resource_start(pdev, 0);
	if (!request_region(ioaddr, pci_id_tbl[chip_idx].io_size, dev->name))
		goto err_out_netdev;
#else
	ioaddr = pci_resource_start(pdev, 1);
	if (!request_mem_region(ioaddr, pci_id_tbl[chip_idx].io_size, dev->name))
		goto err_out_netdev;
	ioaddr = (long) ioremap (ioaddr, pci_id_tbl[chip_idx].io_size);
	if (!ioaddr)
		goto err_out_iomem;
#endif

	printk(KERN_INFO "%s: %s at 0x%lx, ",
		   dev->name, pci_id_tbl[chip_idx].name, ioaddr);

	for (i = 0; i < 3; i++)
		((u16 *)dev->dev_addr)[i] =
			le16_to_cpu(eeprom_read(ioaddr, i + EEPROM_SA_OFFSET));
	for (i = 0; i < 5; i++)
			printk("%2.2x:", dev->dev_addr[i]);
	printk("%2.2x, IRQ %d.\n", dev->dev_addr[i], irq);

	dev->base_addr = ioaddr;
	dev->irq = irq;

	np = dev->priv;
	np->chip_id = chip_idx;
	np->drv_flags = pci_id_tbl[chip_idx].drv_flags;