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lwip-contrib-mac/ports/c16x/netif/cs8900if.c

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/** @file
/*
* Copyright (c) 2001-2003 Leon Woestenberg <leon.woestenberg@axon.tv>
* Copyright (c) 2001-2003 Axon Digital Design B.V., The Netherlands.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Leon Woestenberg <leon.woestenberg@axon.tv>
*
* This is a device driver for the Crystal Semiconductor CS8900
* chip in combination with the lwIP stack.
*
* This is work under development. Please coordinate changes
* and requests with Leon Woestenberg <leon.woestenberg@axon.tv>
*
* The Swedish Institute of Computer Science and Adam Dunkels
* are specifically granted permission to redistribute this
* source code under any conditions they seem fit.
*
* A quick function roadmap:
*
* cs8900_*() are low level, cs8900 hardware specific functions.
* These are declared static in the device driver source and
* SHOULD NOT need to be called from outside this source.
*
* cs8900if_*() are the lwIP network interface functions.
*
* cs8900_interrupt() is an early interrupt service routine (ISR).
* It merely sets a flag to indicate the cs8900 needs servicing.
* (This function MAY be tied to an interrupt vector, IF present).
*
* cs8900_service() is the actual interrupt event service routine.
* It must be called whenever the cs8900 needs servicing. It MAY
* be polled safely (so, you do NOT NEED interrupt support.)
*
* cs8900_init() sets up the cs8900, using its register set. When
* using the driver on your particular hardware platform, make sure
* the register setups match.
* Function is called from cs8900if_init().
*
* cs8900_input() transfers a received packet from the chip.
* Function is called from cs8900if_input().
*
* cs8900_output() transfers a packet to the chip for transmission.
* Function is called from cs8900if_output().
*
* cs8900if_init() initializes the lwIP network interface, and
* calls cs8900_init() to initialize the hardware.
* Function is called from lwIP.
*
* cs8900if_service() is the service routine, which must be called
* upon the need for service, or on a regular basis, in order to
* service the Ethernet chip.
*
* cs8900if_input() calls cs8900_input() to get a received packet
* and then forwards the packet to protocol(s) handler(s).
* Function is called from cs8900_service().
*
* cs8900if_output() resolves the hardware address, then
* calls cs8900_output() to transfer the packet.
* Function is called from lwIP.
*
* Future development:
*
* Split the generic Ethernet functionality (a lot of the
* cs8900if_*() functions) and the actual cs8900a dependencies.
*
* Enhance the interrupt handler to service the Ethernet
* chip (to decrease latency); support early packet
* inspection (during reception) to early drop unwanted
* packets, minimize chip buffer use and maximize throughput.
*
* Statistics gathering, currently under development.
* SNMP support, currently under development.
*
*/
#include "lwip/debug.h"
#include "lwip/opt.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/pbuf.h"
#include "lwip/stats.h"
#include "lwip/sys.h"
#include "netif/etharp.h"
#if 0
// include some debugging help
# define DBG_LEVEL 1
# include "leds.h"
# include "display.h"
//# include "page.h"
# define LED_NEED_SERVICE LED_FP1
#else
// no debugging
# define leds_on()
# define leds_off()
#endif
#include "cs8900if.h"
#if LWIP_SNMP > 0
# include "snmp.h"
#endif
// Define those to better describe your network interface
#define IFNAME0 'e'
#define IFNAME1 'n'
static const struct eth_addr ethbroadcast = {{0xffU,0xffU,0xffU,0xffU,0xffU,0xffU}};
// Forward declarations
static err_t cs8900_output(struct netif *netif, struct pbuf *p);
static struct pbuf *cs8900_input(struct netif *netif);
static void cs8900_service(struct netif *netif);
static u32_t cs8900_chksum(void *dataptr, int len);
// Define these to match your hardware setup
#define MEM_BASE 0x00E000
#define IO_BASE 0x800
#define INT_NR 0x00
#define RXTXREG *((volatile u16_t *)(MEM_BASE + IO_BASE))
#define TXCMD *((volatile u16_t *)(MEM_BASE + IO_BASE + 0x04))
#define TXLENGTH *((volatile u16_t *)(MEM_BASE + IO_BASE + 0x06))
#define ISQ *((volatile u16_t *)(MEM_BASE + IO_BASE + 0x08))
#define PACKETPP *((volatile u16_t *)(MEM_BASE + IO_BASE + 0x0A))
#define PPDATA *((volatile u16_t *)(MEM_BASE + IO_BASE + 0x0C))
// CS8900 PacketPage register offsets
#define CS_PP_EISA 0x0000 // EISA Registration number of CS8900
#define CS_PP_PRODID 0x0002 // Product ID Number
#define CS_PP_IOBASE 0x0020 // I/O Base Address
#define CS_PP_INTNUM 0x0022 // Interrupt number (0,1,2, or 3)
#define CS_PP_RXCFG 0x0102 // Receiver Configuration
#define CS_PP_RXCTL 0x0104 // Receiver Control
#define CS_PP_TXCFG 0x0106 // Transmit Configuration
#define CS_PP_BUFCFG 0x010A // Buffer Configuration
#define CS_PP_LINECTL 0x0112 // Line Control Register offset
#define CS_PP_SELFCTL 0x0114 // Self Control
#define CS_PP_BUSCTL 0x0116 // Bus Control
#define CS_PP_TESTCTL 0x0118 // Test Control
#define CS_PP_ISQ 0x0120 // Interrupt status queue
#define CS_PP_RXEVENT 0x0124 // Receiver Event
#define CS_PP_TX_EVENT 0x0128 // Transmitter Event
#define CS_PP_BUF_EVENT 0x012C // Buffer Event
#define CS_PP_RXMISS 0x0130 // Receiver Miss Counter
#define CS_PP_TXCOL 0x0132 // Transmit Collision Counter
#define CS_PP_LINESTATUS 0x0134 // Line Status
#define CS_PP_SELFTEST 0x0136 // Self Status
#define CS_PP_BUSSTATUS 0x0138 // Bus Status
#define CS_PP_TXCMD 0x0144 // Transmit Command Request
#define CS_PP_TXLEN 0x0146 // Transmit Length
#define CS_PP_IA1 0x0158 // Individual Address (IA)
#define CS_PP_IA2 0x015A // Individual Address (IA)
#define CS_PP_IA3 0x015C // Individual Address (IA)
#define CS_PP_RXSTATUS 0x0400 // Receive Status
#define CS_PP_RXLEN 0x0402 // Receive Length
#define CS_PP_RXFRAME 0x0404 // Receive Frame Location
#define CS_PP_TXFRAME 0x0A00 // Transmit Frame Location
// removed interrupt from library
#if 0
// hardware interrupt vector handler
_interrupt(0x18) void cs8900_interrupt(void)
{
struct cs8900if *cs8900if = cs8900if_netif->state;
// network interface is configured?
if (cs8900if != NULL)
{
// chip needs service
cs8900if->needs_service = 1;
#if (CS8900_STATS > 0)
cs8900if->interrupts++;
#endif
}
}
#endif
// cs8900_init()
//
// initializes the CS8900A chip
//
static void cs8900_init(struct netif *netif)
{
#ifdef LED_NEED_SERVICE
leds_off(LED_NEED_SERVICE);
#endif
// set RESET bit
PACKETPP = CS_PP_SELFCTL;
PPDATA = 0x0055U;
// { the RESET bit will be cleared by the cs8900a
// as a result of the reset }
// RESET bit cleared?
while((PPDATA & 0x0040U) != 0); // TODO: add timeout
// { after full initialization of the cs8900a
// the INITD bit will be set }
PACKETPP = CS_PP_SELFTEST;
// INITD bit still clear?
while ((PPDATA & 0x0080U) == 0); // TODO: add timeout
// { INITD bit is set }
// SIBUSY bit still set?
while ((PPDATA & 0x0100U) == 0x0100); // TODO: add timeout
// { SIBUSY bit clear }
#if 1
{
u16_t dummy;
// datasheet section 3.3.3
dummy = *(u16_t *)(MEM_BASE + IO_BASE + 0x0D);
// Dummy read, put chip in 16-bit mode
dummy = *(u16_t *)(MEM_BASE + IO_BASE + 0x0D);
}
#endif
// Set MAC address
PACKETPP = CS_PP_IA1;
PPDATA = (u16_t)(netif->hwaddr[0]) | (u16_t)(netif->hwaddr[1] << 8U);
PACKETPP = CS_PP_IA2;
PPDATA = (u16_t)(netif->hwaddr[2]) | (u16_t)(netif->hwaddr[3] << 8U);
PACKETPP = CS_PP_IA3;
PPDATA = (u16_t)(netif->hwaddr[4]) | (u16_t)(netif->hwaddr[5] << 8U);
// accept valid unicast or broadcast frames
PACKETPP = CS_PP_RXCTL;
PPDATA = (0x0005U | 0x0800U/*broadcast*/ | 0x0400U/*individual*/ | 0x0100U/*RxOK*/);
// enable receive interrupt
PACKETPP = CS_PP_RXCFG;
PPDATA = (0x0003U | 0x0100U/*RXIRQ*/);
// disable transmit interrupt (is default)
PACKETPP = CS_PP_TXCFG;
PPDATA = (0x0007U | 0);
// use interrupt number 0
PACKETPP = CS_PP_INTNUM;
PPDATA = (0x0000U);
// generate interrupt event on:
// - the RxMISS counter reaches 0x200, or
// - a received frame is lost
PACKETPP = CS_PP_BUFCFG;
PPDATA = (0x000bU |
#if (CS8900_STATS > 0) // interrupt before counter overflow
(0x2000U/*MissOvfloiE*/ | 0x1000U/*TxColOvfloiE*/) |
#endif
#if (CS8900_STATS > 1) // interrupt on counter increment
(0x0400U/*RxMissiE*/) |
#endif
0x0000);
// enable interrupt generation
PACKETPP = CS_PP_BUSCTL;
PPDATA = (0x0017U | 0x8000U/*EnableIRQ*/);
// enable:
// - receiver
// - transmitter
PACKETPP = CS_PP_LINECTL;
PPDATA = (0x0013U | 0x0080U/*SerTxOn*/ | 0x0040U/*SerRxOn*/);
}
static err_t cs8900_output(struct netif *netif, struct pbuf *p)
{
int tries = 0;
// exit if link has failed
PACKETPP = CS_PP_LINESTATUS;
if ((PPDATA & 0x0080U/*LinkOK*/) == 0) return ERR_CONN; // no Ethernet link
/* issue 'transmit' command to CS8900 */
TXCMD = 0x00C9U;
/* send length (in bytes) of packet to send */
TXLENGTH = p->tot_len;
PACKETPP = CS_PP_BUSSTATUS;
// not ready for transmission and still within 100 retries?
while(((PPDATA & 0x0100U/*Rdy4TxNOW*/) == 0) && (tries++ < 100))
{
// throw away the last committed received frame
PACKETPP = CS_PP_RXCFG;
PPDATA = (0x0003U | 0x0040U/*Skip_1*/ | 0x0100U/*RxOKiE*/);
PACKETPP = CS_PP_BUSSTATUS;
/* cs8900if->dropped++; // CHECK: we do not know if we actually will drop a frame here */
}
// ready to transmit?
if((PPDATA & 0x0100U/*Rdy4TxNOW*/) != 0)
{
// q traverses through linked list of pbuf's
struct pbuf *q;
for(q = p; q != NULL; q = q->next)
{
u16_t i;
u16_t *ptr = (u16_t *)q->payload;
// Send the data from the pbuf to the interface, one pbuf at a
// time. The size of the data in each pbuf is kept in the ->len
// variable.
for(i = 0; i < q->len; i += 2)
{
RXTXREG = *ptr++;
}
#if (CS8900_STATS > 0)
((struct cs8900if *)netif->state)->sentbytes += q->len;
#endif
#if LWIP_SNMP > 0
snmp_add_ifoutoctets(p->tot_len);
#endif
#if (CS8900_STATS > 0)
((struct cs8900if *)netif->state)->sentpackets++;
#endif
}
}
else
{
// { not ready to transmit!? }
#if LWIP_SNMP > 0
snmp_inc_ifoutdiscards();
#endif
}
return ERR_OK;
}
/**
* Move a received packet from the cs8900 into a new pbuf.
*
* Must be called after reading an ISQ event containing the
* "Receiver Event" register, before reading new ISQ events.
*
* This function copies a frame from the CS8900A.
* It is designed failsafe:
* - It does not assume a frame is actually present.
* - It checks for non-zero length
* - It does not overflow the frame buffer
*/
static struct pbuf *cs8900_input(struct netif *netif)
{
struct pbuf *p = NULL, *q = NULL;
u16_t len = 0;
u16_t event_type;
u16_t i;
u16_t *ptr = NULL;
// read RxStatus
event_type = RXTXREG;
// correctly received frame, either broadcast or individual address?
// TODO: maybe defer these conditions to cs8900_input()
if ((event_type & 0x0100U/*RxOK*/) && (event_type & 0x0c00U/*Broadcast | Individual*/))
{
#if LWIP_SNMP > 0
// update number of received MAC-unicast and non-MAC-unicast packets
if (event_type & 0x0400U/*Individual*/)
{
snmp_inc_ifinucastpkts();
}
else
{
snmp_inc_ifinnucastpkts();
}
#endif
event_type = 0;
// read RxLength
len = RXTXREG;
DEBUGF(NETIF_DEBUG, ("cs8900_input: packet len %u\n", len));
#if LWIP_SNMP > 0
snmp_add_ifinoctets(len);
#endif
// positive length?
if (len > 0)
{
// allocate a pbuf chain with total length 'len'
p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
if (p != 0)
{
for (q = p; q != 0; q = q->next)
{
DEBUGF(NETIF_DEBUG, ("cs8900_input: pbuf @%p len %u\n", q, q->len));
ptr = q->payload;
// TODO: CHECK: what if q->len is odd? we don't use the last byte?
for (i = 0; i < (q->len + 1) / 2; i++)
{
*ptr = RXTXREG;
ptr++;
}
}
}
// could not allocate a pbuf
else
{
// skip received frame
// TODO: maybe do not skip the frame at this point in time?
PACKETPP = CS_PP_RXCFG;
PPDATA = (0x0003U | 0x0100U/*RxOKiE*/ | 0x0040U/*Skip_1*/);
#if (CS8900_STATS > 0)
((struct cs8900if *)netif->state)->dropped++;
#endif
#if LWIP_SNMP > 0
snmp_inc_ifindiscards();
#endif
len = 0;
}
}
// length was zero
else
{
}
}
return p;
}
/**
* To be called when the cs8900a needs service. Does
* not assume the cs8900a needs service. Does test the
* cs8900a whether it needs service.
*
* As such, may be used robustly called as a deferred
* (or "late") interrupt handler, or may be called in
* a loop to implement polling, or both.
*
* Use cs8900if_service() from your application instead
* of this function.
*/
static void cs8900_service(struct netif *netif)
{
// amount of ISQ's to handle (> 0) in one cs8900_service() call
unsigned char events2service = 1;
// NOTES:
// static, so only initialized to zero at program start.
// irq_status will always hold the last ISQ event register that
// still needs service. As such, we may leave this function if
// we encounter an event we cannot service yet, and return later
// to try to service it.
static u16_t irq_status = 0x0000U;
// The "cs8900_needs_service" flag indicates whether any events
// still need to be serviced.
// clear flag here.
// a receive interrupt can, *concurrently with this function*,
// set this flag on new ISQ event occurences.
// we will re-evaluate the correct setting of this flag at
// function exit (below).
((struct cs8900if *)netif->state)->needs_service = 0;
#ifdef LED_NEED_SERVICE
leds_off(LED_NEED_SERVICE);
#endif
// no unhandled irq_status left?
if (irq_status == 0x0000U)
{
// read ISQ register
irq_status = ISQ;
}
// ISQ interrupt event, and allowed to service in this loop?
while ((irq_status != 0x0000U) && (events2service-- > 0))
{
// investigate event
if ((irq_status & 0x003fU) == 0x0004U/*Receiver Event*/)
{
// correctly received frame, either broadcast or individual address
// TODO: think where these checks should appear: here or in cs8900_input()
if ((irq_status & 0x0100U/*RxOK*/) && (irq_status & 0x0c00U/*Broadcast | Individual*/))
{
// read the frame from the cs8900a
cs8900if_input(netif);
}
else
{
// skip this frame
PACKETPP = CS_PP_RXCFG;
PPDATA |= 0x0040U/*Skip_1*/;
#if (CS8900_STATS > 0)
((struct cs8900if *)netif->state)->dropped++;
#endif
}
}
#if (CS8900_STATS > 0)
else if ((irq_status & 0x003fU) == 0x0010U/*RxMISS Event*/)
{
((struct cs8900if *)netif->state)->missed += (irq_status >> 6);
}
else if ((irq_status & 0x003fU) == 0x0012U/*TxCOL Event*/)
{
((struct cs8900if *)netif->state)->collisions += (irq_status >> 6);
}
#endif
// read ISQ register
irq_status = ISQ;
}
// we did not deplete the ISQ?
if (irq_status != 0x0000U)
{
// the cs8900a still needs service
((struct cs8900if *)netif->state)->needs_service = 1;
#ifdef LED_NEED_SERVICE
leds_on(LED_NEED_SERVICE);
#endif
}
#if (CS8900_STATS > 1)
// read RxMiss Counter (zeroes itself upon read)
PACKETPP = CS_PP_RXMISS;
((struct cs8900if *)netif->state)->missed += (PPDATA >> 6);
// read RxCol Counter (zeroes itself upon read)
PACKETPP = CS_PP_TXCOL;
((struct cs8900if *)netif->state)->collisions += (PPDATA >> 6);
#endif
}
/**
* Service the CS8900.
*
* Can be called in a polling manner, or only after the CS8900 has raised
* an interrupt request.
*
* @param netif The lwIP network interface data structure belonging to this device.
*
*/
void cs8900if_service(struct netif *netif)
{
// is there a reason to call the service routine?
if ((((struct cs8900if *)netif->state)->needs_service) ||
(((struct cs8900if *)netif->state)->use_polling))
{
cs8900_service(netif);
}
}
/**
* Writing an IP packet (to be transmitted) to the CS8900.
*
* Before writing a frame to the CS8900, the ARP module is asked to resolve the
* Ethernet MAC address. The ARP module might undertake actions to resolve the
* address first, and queue this packet for later transmission.
*
* @param netif The lwIP network interface data structure belonging to this device.
* @param p pbuf to be transmitted (or the first pbuf of a chained list of pbufs).
* @param ipaddr destination IP address.
*
* @internal It uses the function cs8900_input() that should handle the actual
* reception of bytes from the network interface.
*
*/
err_t cs8900if_output(struct netif *netif, struct pbuf *p, struct ip_addr *ipaddr)
{
struct cs8900if *cs8900if = netif->state;
p = etharp_output(netif, ipaddr, p);
/* network hardware address obtained? */
if (p != NULL)
{
/* send out the packet */
cs8900_output(netif, p);
p = NULL;
}
// { p == NULL }
else
{
/* we cannot tell if the packet was sent, the packet could have been queued */
/* on an ARP entry that was already pending. */
}
return ERR_OK;
}
/**
* Read a received packet from the CS8900.
*
* This function should be called when a packet is received by the CS8900
* and is fully available to read. It moves the received packet to a pbuf
* which is forwarded to the IP network layer or ARP module. It transmits
* a resulting ARP reply or queued packet.
*
* @param netif The lwIP network interface to read from.
*
* @internal Uses cs8900_input() to move the packet from the CS8900 to a
* newly allocated pbuf.
*
*/
void cs8900if_input(struct netif *netif)
{
struct cs8900if *cs8900if = netif->state;
struct eth_hdr *ethhdr = NULL;
struct pbuf *p = NULL, *q = NULL;
/* move received packet into a new pbuf */
p = cs8900_input(netif);
/* no packet could be read */
if (p == NULL) {
/* silently ignore this */
return;
}
/* points to packet payload, which starts with an Ethernet header */
ethhdr = p->payload;
q = NULL;
switch(htons(ethhdr->type)) {
/* IP packet? */
case ETHTYPE_IP:
/* update ARP table, obtain first queued packet */
q = etharp_ip_input(netif, p);
/* skip Ethernet header */
pbuf_header(p, -14);
/* pass to network layer */
netif->input(p, netif);
break;
/* ARP packet? */
case ETHTYPE_ARP:
/* pass p to ARP module, get ARP reply or ARP queued packet */
q = etharp_arp_input(netif, (struct eth_addr *)&netif->hwaddr, p);
break;
/* unsupported Ethernet packet type */
default:
/* free pbuf */
pbuf_free(p);
p = NULL;
break;
}
/* send out the ARP reply or ARP queued packet */
if (q != NULL) {
/* q pbuf has been succesfully sent? */
if (cs8900_output(netif, q) == ERR_OK)
{
pbuf_free(q);
q = NULL;
}
else
{
/* TODO: re-queue packet in the ARP cache here (?) */
pbuf_free(q);
q = NULL;
}
}
}
/**
* Initialize the CS8900 Ethernet MAC/PHY device driver.
*
* @param netif The lwIP network interface data structure belonging to this device.
*
*/
void cs8900if_init(struct netif *netif)
{
struct cs8900if *cs8900if;
cs8900if = mem_malloc(sizeof(struct cs8900if));
if(cs8900if == NULL) return;
// initialize lwip network interface
netif->name[0] = IFNAME0;
netif->name[1] = IFNAME1;
netif->output = cs8900if_output;
netif->linkoutput = cs8900_output;
// initialize cs8900 specific interface structure
netif->state = cs8900if;
#if 0
/* maximum transfer unit */
netif->mtu = 1500;
/* broadcast capability */
netif->flags = NETIF_FLAG_BROADCAST;
/* hardware address length */
netif->hwaddr_len = 6;
#endif
// initially assume no ISQ event
cs8900if->needs_service = 0;
// set to 1 if polling method is used
cs8900if->use_polling = 0;
#if (CS8900_STATS > 0)
// number of interrupt service routine calls
cs8900if->interrupts = 0;
cs8900if->missed = 0;
cs8900if->dropped = 0;
cs8900if->sentpackets = 0;
cs8900if->sentbytes = 0;
#endif
// intialize the cs8900a chip
cs8900_init(netif);
}
#if 1
/**
* Dump an array of bytes inside a UDP message's data field.
*
* It is a self-contained function, independent of higher protocol layers or other
* functions, so it allows you to debug these higher layers, such as lwIP.
*
* @param p pointer to an array of bytes, at least with length 'len'
* @param len number of bytes available at the address pointed to by 'p'
*/
void cs8900_send_debug(unsigned char *p, unsigned int len)
{
int tries = 0, i;
// network interface state
extern struct netif *ethif;
// exit if link has failed
PACKETPP = CS_PP_LINESTATUS;
if ((PPDATA & 0x0080U/*LinkOK*/) == 0) return; // TODO: find a correct error code
// transmit command
TXCMD = 0x00C9U;
// send at least 60 bytes
TXLENGTH = (14 + 20 + 8 + len < 60) ? 60 : (14 + 20 + 8 + len);
PACKETPP = CS_PP_BUSSTATUS;
// not ready for transmission and still within 100 retries?
while (((PPDATA & 0x0100U/*Rdy4TxNOW*/) == 0) && (tries++ < 100))
{
// throw away the last committed received frame
PACKETPP = CS_PP_RXCFG;
PPDATA = (0x0003U | 0x0040U/*Skip_1*/ | 0x0100U/*RxOKiE*/);
PACKETPP = CS_PP_BUSSTATUS;
/* cs8900if->dropped++; CHECK: we do not know if we actually will drop a frame here, do we? */
}
// ready to transmit?
if((PPDATA & 0x0100U/*Rdy4TxNOW*/) != 0)
{
u16_t data, checksum = 0;
u32_t udp_checksum = 0;
// destination Ethernet address
RXTXREG = 0xa000U;
RXTXREG = 0xc524U;
RXTXREG = 0x6d72U;
// source Ethernet address
RXTXREG = htons(((u16_t)ethif->hwaddr[0] << 8U) | (u16_t)ethif->hwaddr[1]);
RXTXREG = htons(((u16_t)ethif->hwaddr[2] << 8U) | (u16_t)ethif->hwaddr[3]);
RXTXREG = htons(((u16_t)ethif->hwaddr[4] << 8U) | (u16_t)ethif->hwaddr[5]);
// frame type
RXTXREG = htons(0x0800);
// TOS, version
RXTXREG = htons(data = ((0x40 | 0x05) << 8) | 0x00);
checksum += data;
// length
RXTXREG = htons(data = 20 + 8 + len);
checksum += data;
// identifier
RXTXREG = htons(data = 0);
checksum += data;
// fragment offset
RXTXREG = htons(data = 0);
checksum += data;
// TTL, UDP protocol
RXTXREG = htons(data = (255U << 8) | 17U);
checksum += data;
checksum += (htonl(ethif->ip_addr.addr) & 0xffff0000U) >> 16;
checksum += (htonl(ethif->ip_addr.addr) & 0x0000ffffU);
checksum += 0xc0a8U;
checksum += 0x0001U;
checksum += 6; // LW: kludge/hack: checksum calculation seems to be wrong somehow
// LW: this seems (?) to fix it
// checksum
RXTXREG = htons(~checksum);
// source IP
RXTXREG = htons((htonl(ethif->ip_addr.addr) & 0xffff0000U) >> 16);
// source IP
RXTXREG = htons( htonl(ethif->ip_addr.addr) & 0x0000ffffU);
// destination IP
RXTXREG = htons(0xc0a8U);
// destination IP
RXTXREG = htons(0x0001U);
// source port 3000
RXTXREG = htons(3000U);
// destination port 3000
RXTXREG = htons(3000U);
// UDP length
RXTXREG = htons(len);
// UDP checksum (not present)
udp_checksum = (htonl(ethif->ip_addr.addr) & 0xffff0000U) >> 16;
udp_checksum += (htonl(ethif->ip_addr.addr) & 0x0000ffffU);
udp_checksum += 0xc0a8U;
udp_checksum += 0x0001U;
udp_checksum += 0x0011U;
udp_checksum += (8 + len);
udp_checksum += 3000;
udp_checksum += 3000;
udp_checksum += (8 + len);
udp_checksum += cs8900_chksum(p, len);
while(udp_checksum >> 16) {
udp_checksum = (udp_checksum & 0xffffUL) + (udp_checksum >> 16);
}
RXTXREG = htons(~(udp_checksum & 0xffff));
// UDP data
for (i = 0; i < len; i += 2)
{
RXTXREG = htons((p[i] << 8) | p[i + 1]);
}
// pad to 60 bytes
while (i < 60)
{
RXTXREG = 0;
i += 2;
}
}
}
static u32_t cs8900_chksum(void *dataptr, int len)
{
u32_t acc = 0;
u16_t *ptr = (u16_t *)dataptr;
for(acc = 0; len > 1; len -= 2) {
acc += *ptr;
ptr++;
}
/* add up any odd byte */
if(len == 1) {
acc += htons((u16_t)((*(u8_t *)ptr) & 0xffU) << 8);
}
return acc;
}
#endif
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