【 声明：版权所有，欢迎转载，请勿用于商业用途。 联系信箱：feixiaoxing @163.com】
想学好soc，再怎么看芯片手册和linux kernel都不为过。但是要学习好kernel，那再怎么看skyeye都不为过。学习虚拟机，不光可以自己添加soc，也可以自己添加外设硬件（比如网卡、norflash等等），实在不错。
我们自己可以找一段skyeye的soc代码，看看skyeye是怎么仿真外设的，比如1.2.5版本下对ep9312的仿真，
/*skyeye_mach_ep9312.c - define machine ep9312 for skyeye
Copyright (C) 2003 Skyeye Develop Group
for help please send mail to <skyeye-developer@lists.sf.linuxforum.net>
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
*/
/*
* 11/06/2004clean some codes
*wlm <wlm@student.dlut.edu.cn>
* 10/8/2004 init this file.
* add machine ep9312's function.
*Cai Qiang <caiqiang@ustc.edu>
*
* */
#include "armdefs.h"
#include "clps9312.h"
#include "ep9312.h"
#include "serial_amba.h"
//zzc:2005-1-1
#ifdef __CYGWIN__
//chy 2005-07-28
#include <time.h>
//teawater add DBCT_TEST_SPEED 2005.10.04---------------------------------------
/*struct timeval
{
int tv_sec;
int tv_usec;
};*/
//AJ2D--------------------------------------------------------------------------
#endif
/* 2007-01-18 added by Anthony Lee : for new uart device frame */
#include "skyeye_uart.h"
void ep9312_io_write_word (ARMul_State * state, ARMword addr, ARMword data);
ARMword ep9312_io_read_word (ARMul_State * state, ARMword addr);
#define NR_UART3
#define UART_FR_TXFE(1<<7)
#define UART_FR_RXFE(1<<4)
#define UART_IIR_RIS(1<<1)
#define UART_IIR_TIS(1<<2)
const int TCOI[2] = { 1 << 4, 1 << 5 };
const int UART_RXINTR[3] = { 1 << 23, 1 << 25, 1 << 27 };
const int UART_TXINTR[3] = { 1 << 24, 1 << 26, 1 << 28 };
const int INT_UART[3] = { 1 << (52 - 32), 1 << (54 - 32), 1 << (55 - 32) };
const int iConsole = 0;//index of uart of serial console
/*Internal IO Register*/
typedef struct ep9312_io
{
ARMword syscon_devcfg;/* System control */
ARMword intsr[2];/* Interrupt status reg */
ARMword intmr[2];/* Interrupt mask reg */
struct ep9312_tc_io tc[4];
struct ep9312_uart_io uart[NR_UART];
} ep9312_io_t;
static ep9312_io_t ep9312_io;
#define io ep9312_io
static void
ep9312_update_int (ARMul_State * state)
{
ARMword requests = io.intsr[0] & io.intmr[0];
requests |= io.intsr[1] & io.intmr[1];
state->NfiqSig = (requests & 0x0001) ? LOW : HIGH;
state->NirqSig = (requests & 0xfffe) ? LOW : HIGH;
}
static void
ep9312_io_reset (ARMul_State * state)
{
int i;
io.syscon_devcfg = 0;
io.intmr[0] = 0;
io.intmr[1] = 0;
/* reset TC register */
io.tc[0].value = 0;
io.tc[1].value = 0;
io.tc[2].value = 0;
io.tc[0].mod_value = 0xffff;
io.tc[1].mod_value = 0xffff;
io.tc[2].mod_value = 0xffffffff;
for (i = 0; i < NR_UART; i++) {
io.uart[i].dr = 0;
io.uart[i].fr = UART_FR_TXFE;
}
}
void
ep9312_io_do_cycle (ARMul_State * state)
{
int i;
/* We must implement TC1, TC2 and TC4 */
for (i = 0; i < 2; i++) {
if (io.tc[i].value == 0) {
if (io.tc[i].ctl & TC_CTL_MODE)
io.tc[i].value = io.tc[i].load;
else
io.tc[i].value = io.tc[i].mod_value;
io.intsr[0] |= TCOI[i];
ep9312_update_int (state);
}
else {
io.tc[i].value--;
}
}
io.tc[3].load++;
if (!(io.intsr[0] & (UART_RXINTR[iConsole]))
&& io.uart[iConsole].dr == 0) {
/* 2007-01-18 modified by Anthony Lee : for new uart device frame */
struct timeval tv;
unsigned char buf;
tv.tv_sec = 0;
tv.tv_usec = 0;
if(skyeye_uart_read(-1, &buf, 1, &tv, NULL) > 0)
{
io.uart[iConsole].dr = (int) buf;
io.intsr[0] |= UART_RXINTR[iConsole];
io.intmr[0] |= UART_RXINTR[iConsole];
io.intsr[1] |= INT_UART[iConsole];
io.intmr[1] |= INT_UART[iConsole];
io.uart[iConsole].iir |= UART_IIR_RIS;
io.uart[iConsole].fr &= ~UART_FR_RXFE;
ep9312_update_int (state);
}
}//if (!(io.intsr & URXINT))
}
static void
ep9312_uart_read (ARMul_State * state, u32 offset, u32 * data, int index)
{
switch (offset) {
case UART_DR:
*data = io.uart[index].dr;
io.uart[index].dr = 0;
io.intsr[0] &= ~(UART_RXINTR[index]);
io.intsr[1] &= ~(INT_UART[index]);
io.uart[index].iir &= ~UART_IIR_RIS;
io.uart[index].fr |= UART_FR_RXFE;
ep9312_update_int (state);
break;
case UART_RSR:
*data = io.uart[index].rsr;
break;
//case UART_ECR:
case UART_CR_H:
case UART_CR_M:
case UART_CR_L:
break;
case UART_CR:
*data = io.uart[index].cr;
break;
case UART_FR:
*data = io.uart[index].fr;
break;
case UART_IIR:
*data = io.uart[index].iir;
break;
//case UART_ICR:
case UART_ILPR:
case UART_DMACR:
case UART_TCR:
case UART_TISR:
case UART_TOCR:
case UART_TMR:
case UART_MCR:
case UART_MSR:
break;
default:
SKYEYE_DBG ("%s(0x%x, 0x%x)\n", __func__, offset, data);
break;
}
}
static void
ep9312_uart_write (ARMul_State * state, u32 offset, u32 data, int index)
{
switch (offset) {
case UART_DR:
{
char c = data;
/* 2007-01-18 modified by Anthony Lee : for new uart device frame */
skyeye_uart_write(-1, &c, 1, NULL);
}
case UART_RSR:
//case UART_ECR:
case UART_CR_H:
case UART_CR_M:
case UART_CR_L:
break;
case UART_CR:
{
io.uart[index].cr = data;
if ((data & AMBA_UARTCR_TIE) == 0) {
io.intmr[0] &= ~(UART_TXINTR[index]);
io.intsr[0] &= ~(UART_TXINTR[index]);
io.intsr[1] &= ~(INT_UART[index]);
io.intmr[1] &= ~(INT_UART[index]);
io.uart[index].iir &= ~(UART_IIR_TIS);//Interrupt Identification and Clear
}
else {
io.intmr[0] |= (UART_TXINTR[index]);
io.intsr[0] |= (UART_TXINTR[index]);
io.intsr[1] = (INT_UART[index]);
io.intmr[1] = (INT_UART[index]);
io.uart[index].iir |= (UART_IIR_TIS);
}
ep9312_update_int (state);
}
break;
case UART_FR:
case UART_IIR:
io.uart[index].iir = data;
break;
//case UART_ICR:
case UART_ILPR:
case UART_DMACR:
case UART_TCR:
case UART_TISR:
case UART_TOCR:
case UART_TMR:
case UART_MCR:
case UART_MSR:
break;
default:
SKYEYE_DBG ("%s(0x%x, 0x%x)\n", __func__, offset, data);
}
}
/* Timer read/write register
*/
static void
ep9312_tc_read (u32 offset, u32 * data, int index)
{
if (index == 4) {
if (offset == TC_VALUELOW)
*data = io.tc[index].load;
else if (offset == TC_VALUEHIGH)
*data = io.tc[index].value;
}
switch (offset) {
case TC_LOAD:
*data = io.tc[index].load;
break;
case TC_VALUE:
*data = io.tc[index].value;
break;
case TC_CTL:
*data = io.tc[index].ctl;
break;
case TC_CLEAR:
SKYEYE_DBG ("%s(0x%x, 0x%x): read WO register\n", __func__,
offset, data);
break;
default:
SKYEYE_DBG ("%s(0x%x, 0x%x)\n", __func__, offset, data);
break;
}
}
static void
ep9312_tc_write (ARMul_State * state, u32 offset, u32 data, int index)
{
switch (offset) {
case TC_LOAD:
io.tc[index].load = data;
break;
case TC_VALUE:
SKYEYE_DBG ("%s(0x%x, 0x%x): write RO register\n", __func__,
offset, data);
break;
case TC_CTL:
io.tc[index].ctl = data;
break;
case TC_CLEAR:
io.intsr[0] &= ~TCOI[index];
ep9312_update_int (state);
break;
default:
SKYEYE_DBG ("%s(0x%x, 0x%x)\n", __func__, offset, data);
break;
}
}
ARMword
ep9312_io_read_byte (ARMul_State * state, ARMword addr)
{
return ep9312_io_read_word (state, addr);
}
ARMword
ep9312_io_read_halfword (ARMul_State * state, ARMword addr)
{
SKYEYE_DBG ("SKYEYE: %s error\n", __func__);
}
ARMword
ep9312_io_read_word (ARMul_State * state, ARMword addr)
{
ARMword data = 0;
/* TC1 */
if ((addr >= EP9312_TC_BASE1) &&
(addr < (EP9312_TC_BASE1 + EP9312_TC_SIZE))) {
ep9312_tc_read ((u32) (addr - EP9312_TC_BASE1),
(u32 *) & data, 0);
}
/* TC2 */
if ((addr >= EP9312_TC_BASE4) &&
(addr < (EP9312_TC_BASE4 + EP9312_TC_SIZE))) {
ep9312_tc_read ((u32) (addr - EP9312_TC_BASE4),
(u32 *) & data, 3);
}
/* UART1 */
if ((addr >= EP9312_UART_BASE1) &&
(addr < (EP9312_UART_BASE1 + EP9312_UART_SIZE))) {
ep9312_uart_read (state, (u32) (addr - EP9312_UART_BASE1),
(u32 *) & data, 0);
return data;
}
/* UART3 */
if ((addr >= EP9312_UART_BASE3) &&
(addr < (EP9312_UART_BASE3 + EP9312_UART_SIZE))) {
ep9312_uart_read (state, (u32) (addr - EP9312_UART_BASE3),
(u32 *) & data, 2);
return data;
}
switch (addr) {
case SYSCON_PWRCNT:
break;
case VIC0INTENABLE:
data = io.intmr[0];
// printf("%s(0x%08x) = 0x%08x\n", __func__, addr, data);
break;
case VIC0IRQSTATUS:
data = io.intsr[0];
io.intsr[0] = 0;//!!!
break;
case VIC1IRQSTATUS:
data = io.intsr[1];
io.intsr[1] = 0;
break;
case RTCDR:
case AACGCR:
case AACRGIS:
// printf("%s(0x%08x) = 0x%08x\n", __func__, addr, data);
break;
case SYSCON_DEVCFG:
data = io.syscon_devcfg;
break;
default:
SKYEYE_DBG ("SKYEYE:unknown io addr, %s(0x%08x) = 0x%08x\n",
__func__, addr, data);
break;
}
return data;
}
void
ep9312_io_write_byte (ARMul_State * state, ARMword addr, ARMword data)
{
ep9312_io_write_word (state, addr, data);
}
void
ep9312_io_write_halfword (ARMul_State * state, ARMword addr, ARMword data)
{
SKYEYE_DBG ("SKYEYE: %s error\n", __func__);
}
void
ep9312_io_write_word (ARMul_State * state, ARMword addr, ARMword data)
{
ARMword tmp;
if ((addr >= EP9312_TC_BASE1) &&
(addr < (EP9312_TC_BASE1 + EP9312_TC_SIZE))) {
ep9312_tc_write (state, (u32) (addr - EP9312_TC_BASE1), data,
0);
}
if ((addr >= EP9312_UART_BASE1) &&
(addr < (EP9312_UART_BASE1 + EP9312_UART_SIZE))) {
ep9312_uart_write (state, (u32) (addr - EP9312_UART_BASE1),
data, 0);
}
if ((addr >= EP9312_UART_BASE3) &&
(addr < (EP9312_UART_BASE3 + EP9312_UART_SIZE))) {
ep9312_uart_write (state, (u32) (addr - EP9312_UART_BASE3),
data, 2);
}
switch (addr) {
case SYSCON_CLKSET1:
break;
case SYSCON_CLKSET2:
case SYSCON_PWRCNT:
break;
case VIC0INTENABLE:
io.intmr[0] = data;
if (data != 0x10 && data != 0x20)
printf ("SKYEYE: write VIC0INTENABLE=0x%x\n", data);
ep9312_update_int (state);
break;
case VIC1INTENABLE:
io.intmr[1] = data;
// printf("SKYEYE: write VIC1INTENABLE=0x%x\n", data);
ep9312_update_int (state);
break;
case VIC0INTENCLEAR:
io.intmr[0] ^= data;
ep9312_update_int (state);
break;
case VIC1INTENCLEAR:
io.intmr[1] ^= data;
ep9312_update_int (state);
break;
case SYSCON_DEVCFG:
io.syscon_devcfg = data;
break;
default:
SKYEYE_DBG
("SKYEYE:unknown io addr, %s(0x%08x, 0x%08x), pc %x \n",
__func__, addr, data, state->Reg[15]);
break;
}
}
void
ep9312_mach_init (ARMul_State * state, machine_config_t * this_mach)
{
ARMul_SelectProcessor (state, ARM_v4_Prop);
/* ARM920T uses LOW */
state->lateabtSig = LOW;
// state->Reg[1] = 282; //for EP9312 2.4.x arch id
state->Reg[1] = 451;//for EP9312 2.6.x arch id
//state->Reg[1] = 386; //for EP9315 2.4.x arch id
this_mach->mach_io_do_cycle = ep9312_io_do_cycle;
this_mach->mach_io_reset = ep9312_io_reset;
this_mach->mach_io_read_byte = ep9312_io_read_byte;
this_mach->mach_io_write_byte = ep9312_io_write_byte;
this_mach->mach_io_read_halfword = ep9312_io_read_halfword;
this_mach->mach_io_write_halfword = ep9312_io_write_halfword;
this_mach->mach_io_read_word = ep9312_io_read_word;
this_mach->mach_io_write_word = ep9312_io_write_word;
this_mach->mach_update_int = ep9312_update_int;
}
我觉得soc仿真的意义在于让外设的地址读写变得有意义，比如如何让串口地址进行输出、让时钟进行计数、让中断可以真正地发挥作用。上面这段代码看上去行数很多，但是最重要的还是最后一个函数。当然，除此之外，系统注册也是必不可少的，
machine_config_t arm_machines[] = {/* machine define for cpu without mmu */{"at91", at91_mach_init, NULL, NULL, NULL},/* ATMEL AT91X40 */{"lpc", lpc_mach_init, NULL, NULL, NULL},/* PHILIPS LPC2xxxx */{"s3c4510b", s3c4510b_mach_init, NULL, NULL, NULL},/* Samsung s3c4510b */{"s3c44b0x", s3c44b0x_mach_init, NULL, NULL, NULL},/* Samsung s3c44b0x */{"s3c44b0", s3c44b0x_mach_init, NULL, NULL, NULL},/* Samsung s3c44b0x */{"s3c3410x", s3c3410x_mach_init, NULL, NULL, NULL},/* Samsung s3c3410x *//* machine define for cpu with mmu */{"ep7312", ep7312_mach_init, NULL, NULL, NULL},/* Cirrus Logic EP7312 */{"lh79520", lh79520_mach_init, NULL, NULL, NULL},/* sharp LH79520 */{"ep9312", ep9312_mach_init, NULL, NULL, NULL},/* Cirrus Logic EP9312 */{"cs89712", cs89712_mach_init, NULL, NULL, NULL},/* cs89712 */{"sa1100", sa1100_mach_init, NULL, NULL, NULL},/* sa1100 */{"pxa_lubbock", pxa250_mach_init, NULL, NULL, NULL},/* xscale pxa250 lubbock developboard */{"pxa_mainstone", pxa270_mach_init, NULL, NULL, NULL},/* xscale pxa270 mainstone developboard */{"at91rm92", at91rm92_mach_init, NULL, NULL, NULL},/* at91RM9200 */{"s3c2410x", s3c2410x_mach_init, NULL, NULL, NULL},/* s3c2410x */{"s3c2440", s3c2440_mach_init, NULL, NULL, NULL},/* s3c2440 */{"sharp_lh7a400", shp_mach_init, NULL, NULL, NULL},/* sharp lh7a400 developboard */{"ns9750", ns9750_mach_init, NULL, NULL, NULL},/* NetSilicon ns9750 */{"lpc2210", lpc2210_mach_init, NULL, NULL, NULL},/* Philips LPC2210 */{"ps7500", ps7500_mach_init, NULL, NULL, NULL},/* Cirrus Logic PS7500FE */};
有了这两个文件，基本上soc的逻辑算是了解了。