/* hamachi.c: A Packet Engines GNIC-II Gigabit Ethernet driver for Linux. */ /* Written 1998-2000 by Donald Becker. Updates 2000 by Keith Underwood. 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 [email protected], or C/O Scyld Computing Corporation 410 Severn Ave., Suite 210 Annapolis MD 21403 This driver is for the Packet Engines GNIC-II PCI Gigabit Ethernet adapter. Support and updates available at http://www.scyld.com/network/hamachi.html [link no longer provides useful info -jgarzik] or http://www.parl.clemson.edu/~keithu/hamachi.html */ #define DRV_NAME … #define DRV_VERSION … #define DRV_RELDATE … /* A few user-configurable values. */ static int debug = …; /* 1 normal messages, 0 quiet .. 7 verbose. */ #define final_version #define hamachi_debug … /* Maximum events (Rx packets, etc.) to handle at each interrupt. */ static int max_interrupt_work = …; static int mtu; /* Default values selected by testing on a dual processor PIII-450 */ /* These six interrupt control parameters may be set directly when loading the * module, or through the rx_params and tx_params variables */ static int max_rx_latency = …; static int max_rx_gap = …; static int min_rx_pkt = …; static int max_tx_latency = …; static int max_tx_gap = …; static int min_tx_pkt = …; /* Set the copy breakpoint for the copy-only-tiny-frames scheme. -Setting to > 1518 causes all frames to be copied -Setting to 0 disables copies */ static int rx_copybreak; /* An override for the hardware detection of bus width. Set to 1 to force 32 bit PCI bus detection. Set to 4 to force 64 bit. Add 2 to disable parity detection. */ static int force32; /* Used to pass the media type, etc. These exist for driver interoperability. No media types are currently defined. - The lower 4 bits are reserved for the media type. - The next three bits may be set to one of the following: 0x00000000 : Autodetect PCI bus 0x00000010 : Force 32 bit PCI bus 0x00000020 : Disable parity detection 0x00000040 : Force 64 bit PCI bus Default is autodetect - The next bit can be used to force half-duplex. This is a bad idea since no known implementations implement half-duplex, and, in general, half-duplex for gigabit ethernet is a bad idea. 0x00000080 : Force half-duplex Default is full-duplex. - In the original driver, the ninth bit could be used to force full-duplex. Maintain that for compatibility 0x00000200 : Force full-duplex */ #define MAX_UNITS … static int options[MAX_UNITS] = …; static int full_duplex[MAX_UNITS] = …; /* The Hamachi chipset supports 3 parameters each for Rx and Tx * interruput management. Parameters will be loaded as specified into * the TxIntControl and RxIntControl registers. * * The registers are arranged as follows: * 23 - 16 15 - 8 7 - 0 * _________________________________ * | min_pkt | max_gap | max_latency | * --------------------------------- * min_pkt : The minimum number of packets processed between * interrupts. * max_gap : The maximum inter-packet gap in units of 8.192 us * max_latency : The absolute time between interrupts in units of 8.192 us * */ static int rx_params[MAX_UNITS] = …; static int tx_params[MAX_UNITS] = …; /* 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. There are no ill effects from too-large receive rings, except for excessive memory usage */ /* Empirically it appears that the Tx ring needs to be a little bigger for these Gbit adapters or you get into an overrun condition really easily. Also, things appear to work a bit better in back-to-back configurations if the Rx ring is 8 times the size of the Tx ring */ #define TX_RING_SIZE … #define RX_RING_SIZE … #define TX_TOTAL_SIZE … #define RX_TOTAL_SIZE … /* * Enable netdev_ioctl. Added interrupt coalescing parameter adjustment. * 2/19/99 Pete Wyckoff <[email protected]> */ /* play with 64-bit addrlen; seems to be a teensy bit slower --pw */ /* #define ADDRLEN 64 */ /* * RX_CHECKSUM turns on card-generated receive checksum generation for * TCP and UDP packets. Otherwise the upper layers do the calculation. * 3/10/1999 Pete Wyckoff <[email protected]> */ #define RX_CHECKSUM /* Operational parameters that usually are not changed. */ /* Time in jiffies before concluding the transmitter is hung. */ #define TX_TIMEOUT … #include <linux/capability.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/timer.h> #include <linux/time.h> #include <linux/errno.h> #include <linux/ioport.h> #include <linux/interrupt.h> #include <linux/pci.h> #include <linux/init.h> #include <linux/ethtool.h> #include <linux/mii.h> #include <linux/netdevice.h> #include <linux/etherdevice.h> #include <linux/skbuff.h> #include <linux/ip.h> #include <linux/delay.h> #include <linux/bitops.h> #include <linux/uaccess.h> #include <asm/processor.h> /* Processor type for cache alignment. */ #include <asm/io.h> #include <asm/unaligned.h> #include <asm/cache.h> static const char version[] = …; /* IP_MF appears to be only defined in <netinet/ip.h>, however, we need it for hardware checksumming support. FYI... some of the definitions in <netinet/ip.h> conflict/duplicate those in other linux headers causing many compiler warnings. */ #ifndef IP_MF #define IP_MF … #endif /* Define IP_OFFSET to be IPOPT_OFFSET */ #ifndef IP_OFFSET #ifdef IPOPT_OFFSET #define IP_OFFSET … #else #define IP_OFFSET … #endif #endif #define RUN_AT(x) … #ifndef ADDRLEN #define ADDRLEN … #endif /* Condensed bus+endian portability operations. */ #if ADDRLEN == 64 #define cpu_to_leXX … #define leXX_to_cpu … #else #define cpu_to_leXX(addr) … #define leXX_to_cpu(addr) … #endif /* Theory of Operation I. Board Compatibility This device driver is designed for the Packet Engines "Hamachi" Gigabit Ethernet chip. The only PCA currently supported is the GNIC-II 64-bit 66Mhz PCI card. II. Board-specific settings No jumpers exist on the board. The chip supports software correction of various motherboard wiring errors, however this driver does not support that feature. III. Driver operation IIIa. Ring buffers The Hamachi uses a typical descriptor based bus-master architecture. The descriptor list is similar to that used by the Digital Tulip. 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. This driver uses a zero-copy receive and transmit scheme similar my other network drivers. The driver allocates full frame size skbuffs for the Rx ring buffers at open() time and passes the skb->data field to the Hamachi 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 and replaced by a newly allocated skbuff. 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. Gigabit cards are typically used on 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. IIIb/c. Transmit/Receive Structure The Rx and Tx descriptor structure are straight-forward, with no historical baggage that must be explained. Unlike the awkward DBDMA structure, there are no unused fields or option bits that had only one allowable setting. Two details should be noted about the descriptors: The chip supports both 32 bit and 64 bit address structures, and the length field is overwritten on the receive descriptors. The descriptor length is set in the control word for each channel. The development driver uses 32 bit addresses only, however 64 bit addresses may be enabled for 64 bit architectures e.g. the Alpha. IIId. Synchronization This driver is very similar to my other network drivers. 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 other 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 'hmp->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 'hmp->tx_full' flag is set, it clears both the tx_full and tbusy flags. IV. Notes Thanks to Kim Stearns of Packet Engines for providing a pair of GNIC-II boards. IVb. References Hamachi Engineering Design Specification, 5/15/97 (Note: This version was marked "Confidential".) IVc. Errata None noted. V. Recent Changes 01/15/1999 EPK Enlargement of the TX and RX ring sizes. This appears to help avoid some stall conditions -- this needs further research. 01/15/1999 EPK Creation of the hamachi_tx function. This function cleans the Tx ring and is called from hamachi_start_xmit (this used to be called from hamachi_interrupt but it tends to delay execution of the interrupt handler and thus reduce bandwidth by reducing the latency between hamachi_rx()'s). Notably, some modification has been made so that the cleaning loop checks only to make sure that the DescOwn bit isn't set in the status flag since the card is not required to set the entire flag to zero after processing. 01/15/1999 EPK In the hamachi_start_tx function, the Tx ring full flag is checked before attempting to add a buffer to the ring. If the ring is full an attempt is made to free any dirty buffers and thus find space for the new buffer or the function returns non-zero which should case the scheduler to reschedule the buffer later. 01/15/1999 EPK Some adjustments were made to the chip initialization. End-to-end flow control should now be fully active and the interrupt algorithm vars have been changed. These could probably use further tuning. 01/15/1999 EPK Added the max_{rx,tx}_latency options. These are used to set the rx and tx latencies for the Hamachi interrupts. If you're having problems with network stalls, try setting these to higher values. Valid values are 0x00 through 0xff. 01/15/1999 EPK In general, the overall bandwidth has increased and latencies are better (sometimes by a factor of 2). Stalls are rare at this point, however there still appears to be a bug somewhere between the hardware and driver. TCP checksum errors under load also appear to be eliminated at this point. 01/18/1999 EPK Ensured that the DescEndRing bit was being set on both the Rx and Tx rings. This appears to have been affecting whether a particular peer-to-peer connection would hang under high load. I believe the Rx rings was typically getting set correctly, but the Tx ring wasn't getting the DescEndRing bit set during initialization. ??? Does this mean the hamachi card is using the DescEndRing in processing even if a particular slot isn't in use -- hypothetically, the card might be searching the entire Tx ring for slots with the DescOwn bit set and then processing them. If the DescEndRing bit isn't set, then it might just wander off through memory until it hits a chunk of data with that bit set and then looping back. 02/09/1999 EPK Added Michel Mueller's TxDMA Interrupt and Tx-timeout problem (TxCmd and RxCmd need only to be set when idle or stopped. 02/09/1999 EPK Added code to check/reset dev->tbusy in hamachi_interrupt. (Michel Mueller pointed out the ``permanently busy'' potential problem here). 02/22/1999 EPK Added Pete Wyckoff's ioctl to control the Tx/Rx latencies. 02/23/1999 EPK Verified that the interrupt status field bits for Tx were incorrectly defined and corrected (as per Michel Mueller). 02/23/1999 EPK Corrected the Tx full check to check that at least 4 slots were available before resetting the tbusy and tx_full flags (as per Michel Mueller). 03/11/1999 EPK Added Pete Wyckoff's hardware checksumming support. 12/31/1999 KDU Cleaned up assorted things and added Don's code to force 32 bit. 02/20/2000 KDU Some of the control was just plain odd. Cleaned up the hamachi_start_xmit() and hamachi_interrupt() code. There is still some re-structuring I would like to do. 03/01/2000 KDU Experimenting with a WIDE range of interrupt mitigation parameters on a dual P3-450 setup yielded the new default interrupt mitigation parameters. Tx should interrupt VERY infrequently due to Eric's scheme. Rx should be more often... 03/13/2000 KDU Added a patch to make the Rx Checksum code interact nicely with non-linux machines. 03/13/2000 KDU Experimented with some of the configuration values: -It seems that enabling PCI performance commands for descriptors (changing RxDMACtrl and TxDMACtrl lower nibble from 5 to D) has minimal performance impact for any of my tests. (ttcp, netpipe, netperf) I will leave them that way until I hear further feedback. -Increasing the PCI_LATENCY_TIMER to 130 (2 + (burst size of 128 * (0 wait states + 1))) seems to slightly degrade performance. Leaving default at 64 pending further information. 03/14/2000 KDU Further tuning: -adjusted boguscnt in hamachi_rx() to depend on interrupt mitigation parameters chosen. -Selected a set of interrupt parameters based on some extensive testing. These may change with more testing. TO DO: -Consider borrowing from the acenic driver code to check PCI_COMMAND for PCI_COMMAND_INVALIDATE. Set maximum burst size to cache line size in that case. -fix the reset procedure. It doesn't quite work. */ /* A few values that may be tweaked. */ /* Size of each temporary Rx buffer, calculated as: * 1518 bytes (ethernet packet) + 2 bytes (to get 8 byte alignment for * the card) + 8 bytes of status info + 8 bytes for the Rx Checksum */ #define PKT_BUF_SZ … /* For now, this is going to be set to the maximum size of an ethernet * packet. Eventually, we may want to make it a variable that is * related to the MTU */ #define MAX_FRAME_SIZE … /* The rest of these values should never change. */ static void hamachi_timer(struct timer_list *t); enum capability_flags { … }; static const struct chip_info { … } chip_tbl[] = …; /* Offsets to the Hamachi registers. Various sizes. */ enum hamachi_offsets { … }; /* Offsets to the MII-mode registers. */ enum MII_offsets { … }; /* Bits in the interrupt status/mask registers. */ enum intr_status_bits { … }; /* The Hamachi Rx and Tx buffer descriptors. */ struct hamachi_desc { … }; /* Bits in hamachi_desc.status_n_length */ enum desc_status_bits { … }; #define PRIV_ALIGN … #define MII_CNT … struct hamachi_private { … }; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …; module_param(max_interrupt_work, int, 0); module_param(mtu, int, 0); module_param(debug, int, 0); module_param(min_rx_pkt, int, 0); module_param(max_rx_gap, int, 0); module_param(max_rx_latency, int, 0); module_param(min_tx_pkt, int, 0); module_param(max_tx_gap, int, 0); module_param(max_tx_latency, int, 0); module_param(rx_copybreak, int, 0); module_param_array(…); module_param_array(…); module_param_array(…); module_param_array(…); module_param(force32, int, 0); MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; MODULE_PARM_DESC(…) …; static int read_eeprom(void __iomem *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 hamachi_open(struct net_device *dev); static int hamachi_ioctl(struct net_device *dev, struct ifreq *rq, int cmd); static int hamachi_siocdevprivate(struct net_device *dev, struct ifreq *rq, void __user *data, int cmd); static void hamachi_timer(struct timer_list *t); static void hamachi_tx_timeout(struct net_device *dev, unsigned int txqueue); static void hamachi_init_ring(struct net_device *dev); static netdev_tx_t hamachi_start_xmit(struct sk_buff *skb, struct net_device *dev); static irqreturn_t hamachi_interrupt(int irq, void *dev_instance); static int hamachi_rx(struct net_device *dev); static inline int hamachi_tx(struct net_device *dev); static void hamachi_error(struct net_device *dev, int intr_status); static int hamachi_close(struct net_device *dev); static struct net_device_stats *hamachi_get_stats(struct net_device *dev); static void set_rx_mode(struct net_device *dev); static const struct ethtool_ops ethtool_ops; static const struct ethtool_ops ethtool_ops_no_mii; static const struct net_device_ops hamachi_netdev_ops = …; static int hamachi_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) { … } static int read_eeprom(void __iomem *ioaddr, int location) { … } /* MII Managemen Data I/O accesses. These routines assume the MDIO controller is idle, and do not exit until the command is finished. */ 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 hamachi_open(struct net_device *dev) { … } static inline int hamachi_tx(struct net_device *dev) { … } static void hamachi_timer(struct timer_list *t) { … } static void hamachi_tx_timeout(struct net_device *dev, unsigned int txqueue) { … } /* Initialize the Rx and Tx rings, along with various 'dev' bits. */ static void hamachi_init_ring(struct net_device *dev) { … } static netdev_tx_t hamachi_start_xmit(struct sk_buff *skb, struct net_device *dev) { … } /* The interrupt handler does all of the Rx thread work and cleans up after the Tx thread. */ static irqreturn_t hamachi_interrupt(int irq, void *dev_instance) { … } /* This routine is logically part of the interrupt handler, but separated for clarity and better register allocation. */ static int hamachi_rx(struct net_device *dev) { … } /* This is more properly named "uncommon interrupt events", as it covers more than just errors. */ static void hamachi_error(struct net_device *dev, int intr_status) { … } static int hamachi_close(struct net_device *dev) { … } static struct net_device_stats *hamachi_get_stats(struct net_device *dev) { … } static void set_rx_mode(struct net_device *dev) { … } static int check_if_running(struct net_device *dev) { … } static void hamachi_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) { … } static int hamachi_get_link_ksettings(struct net_device *dev, struct ethtool_link_ksettings *cmd) { … } static int hamachi_set_link_ksettings(struct net_device *dev, const struct ethtool_link_ksettings *cmd) { … } static int hamachi_nway_reset(struct net_device *dev) { … } static u32 hamachi_get_link(struct net_device *dev) { … } static const struct ethtool_ops ethtool_ops = …; static const struct ethtool_ops ethtool_ops_no_mii = …; /* private ioctl: set rx,tx intr params */ static int hamachi_siocdevprivate(struct net_device *dev, struct ifreq *rq, void __user *data, int cmd) { … } static int hamachi_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) { … } static void hamachi_remove_one(struct pci_dev *pdev) { … } static const struct pci_device_id hamachi_pci_tbl[] = …; MODULE_DEVICE_TABLE(pci, hamachi_pci_tbl); static struct pci_driver hamachi_driver = …; static int __init hamachi_init (void) { … } static void __exit hamachi_exit (void) { … } module_init(…) …; module_exit(hamachi_exit);
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