PCI设备初始化编程的过程
这里以PowerPC上的PCI设备为例,介绍PCI设备初始化编程的过程,其他CPU的PCI基本框架是类似的.
PowerPC的PCI控制器符合PCI2.2标准,以下使我解读的VxWorks系统PCI设备程序代码分析
主要执行过程
1.初始化PCI设备
文件romInit.s中romInit()=======>文件bootInit.c中romStart()========>文件usrConfig.c中的usrInit()======>文件syslib.c中的sysHwInit()
syslib.c
void sysHwInit (void){ //用于初始化系统硬件
......................
//和网络,PCI有关的函数
#ifdef INCLUDE_EMAC_NETWORK
//初始化媒介访问层MAL(控制EMAC和Buffer Descriptor BD间的数据传输)
malReset();
#endif
#ifdef INCLUDE_PCI
pciInit(); //初始化PCI
#endif
#ifdef INCLUDE_NETWORK
sysNetHwInit(); //初始化网络接口
#endif
}
//该函数初始化PCI
PCI的地址转换形式:
CPU->PCI (master/initiator) 地址转换
PCI->CPU (slave/target) 地址转换
void pciInit()
{
unsigned short temp_short;
/*
* 初始化并 disable 所有的 PCI Master regions(三个),
little endian,直接对寄存器R操作 */
sysPciOutLong(PMM0MA, PMM_UNUSED);
sysPciOutLong(PMM1MA, PMM_UNUSED);
sysPciOutLong(PMM2MA, PMM_UNUSED);
/*
解释:
PMM0MA:地址 0xEE400004, 控制PLB上的映射到PCI存储空间的range0大小和属性.
在PLB上共有三个ranges, PMM1MA代表区域rang1, PMM2MA代表区域range2.
PMM_UNUSED: 0x00000000
range的定义
range: map PLB======>PCI 64-bit
PPBridge(PLB和PCI设备间的接口)responds as a target on the PLB bus in servral address ranges.
These ranges allow a PLB Master to configure the PPBridge and to cause PPBridge to generate Mem I/O,interrupt acknowledge and special cycles to PCI bus.
*/
/*
* Initially disable PCI Target region 2 to start. Region 1 is hardwired
* to always be active.
*/
//PTM2MS:地址 0xEF400038,定义PCI存储空间的大小.这里清零
sysPciOutLong(PTM2MS, PTM_UNUSED);
/*
* Drive PCI 重新置位. 用于热启动,置位必须保持1ms
*/
//解释: 从PCI寄存器PCI_CFG_BRIDGE_OPT2中读出数值
其中 PPC405GP_PCI_BUSDEVFUNC = 0x00000000;
PCI_CFG_BRIDGE_OPT2 = 0x60
temp_short = pciConfigIn(PPC405GP_PCI_BUSDEVFUNC, PCI_CFG_BRIDGE_OPT2, 2);
//把读出的值放回寄存器PCI_CFG_BRIDGE_OPT2中
pciConfigOut(PPC405GP_PCI_BUSDEVFUNC, PCI_CFG_BRIDGE_OPT2,
temp_short | 0x1000, 2);
sysLocalDelay(1); /* 延时1ms kernel may not be up yet!! */
//再放一次
pciConfigOut(PPC405GP_PCI_BUSDEVFUNC, PCI_CFG_BRIDGE_OPT2, temp_short, 2);
/*
* 设置PCI Master(PMM),这是从本地存储地址Local memory address到PCI空间的映射 * CPU->PCI,参见文件 See config.h中的定义,参考 BSP配置文件
*/{{分页}}
//说明sysPciOutLong(A,B);放B到A
//PMM region 0
//PMM0LA 0xEF400000, PMM0_LOCAL_ADRS 0x80000000
sysPciOutLong(PMM0LA, PMM0_LOCAL_ADRS);
//PMM0PCILA 0xEF400008, PMM0_PCI_LOW_ADRS 0x80000000
sysPciOutLong(PMM0PCILA, PMM0_PCI_LOW_ADRS);
//PMM0PCIHA 0xEF40000C, PMM0_PCI_HIGH_ADRS 0x00000000
sysPciOutLong(PMM0PCIHA, PMM0_PCI_HIGH_ADRS);
//PMM0MA 0xEF400004,
//PMM0_PCI_MASK_ATTRIB PMM_MASK_512MB|PMM_ENABLE
sysPciOutLong(PMM0MA, PMM0_PCI_MASK_ATTRIB);
sysPciOutLong(PMM1LA, PMM1_LOCAL_ADRS); /* PMM region 1 */
sysPciOutLong(PMM1PCILA, PMM1_PCI_LOW_ADRS);
sysPciOutLong(PMM1PCIHA, PMM1_PCI_HIGH_ADRS);
sysPciOutLong(PMM1MA, PMM1_PCI_MASK_ATTRIB);
sysPciOutLong(PMM2LA, PMM2_LOCAL_ADRS); /* PMM region 2 */
sysPciOutLong(PMM2PCILA, PMM2_PCI_LOW_ADRS);
sysPciOutLong(PMM2PCIHA, PMM2_PCI_HIGH_ADRS);
sysPciOutLong(PMM2MA, PMM2_PCI_MASK_ATTRIB);
/*
* 设置 PCI Target (PTM). 这是从PCI的地址到本地地址的映射
* 参见文件 config.h中的定义
* 如果不是用 region 2, 必须保证它的使能位关闭,region 1硬件连接使能.
*/
//PTM1LA 0xEF400034, PTM1_LOCAL_ADRS 0x00000000
sysPciOutLong(PTM1LA, PTM1_LOCAL_ADRS);
//PTM1MS 0xEF400030,
sysPciOutLong(PTM1MS, PTM1_SIZE_ATTRIB);
...................
/*
* 写 405GP PCI 设置寄存器.
* 使能 405GP,使其成为PCI总线的一个master (PMM).
* 使能 405GP 作为一个PCI memory target (PTM).
*/
temp_short = pciConfigIn(PPC405GP_PCI_BUSDEVFUNC, PCI_CFG_COMMAND, 2);
temp_short = temp_short | PCI_CMD_MASTER_ENABLE | PCI_CMD_MEM_ENABLE;
pciConfigOut(PPC405GP_PCI_BUSDEVFUNC, PCI_CFG_COMMAND, temp_short, 2);
..........................
/*
* 作为PCI的主机host扫描PCI总线,查找PCI设备. 并为每个设备分配唯一的PCI或I/O地址* 空间
*/
pciScan(0);
return;
}
//pciScan() - 扫描PCI总线,根据PCI ID和 vender ID查找设置现有的PCI设备
void pciScan
(
int busNum
)
{
int Device;
int BusDevFunc;
/*
* 从device 1开始,查找每个Slot,如有PCI设备,分配内存和I/O, 405GP是 device 0.
*/
for (Device = 1; Device <= WALNUT_NUM_PCI_SLOTS; Device++)
{
BusDevFunc = (busNum << 16) | (Device << 11);
//如果Device存在
if (pciConfigIn(BusDevFunc, PCI_CFG_VENDOR_ID,2) != 0xFFFF)
{
#ifdef PCIDEBUG
printf("* * * * * * * * * * * * * * * * *n");
printf("Device %d is presentn",Device);
#endif
switch( pciConfigIn(BusDevFunc, PCI_CFG_SUBCLASS, 2) )
{
case 0x0604: /* PCI-PCI Bridge */
break;
default:
pciDumpDevice(BusDevFunc); //打印 Vendor ID, Device ID
//调用pciConfigDevice(BusDevFunc, 6)对PCI设备进行设置
pciConfigDevice(BusDevFunc, 6);
}
}
else
{
#ifdef PCIDEBUG
printf("Device %d not presentn",Device);
#endif
}
}
}
//pciConfigDevice - 为PCI设备配置内存和I/O方式
void pciConfigDevice(int BusDevFunc,int NumBaseAddr)
{
int AddrSlot;
int i;
unsigned long AddrDesc;
unsigned long AddrProg;
unsigned long Min_Gnt_Val;
// NumBaseAddr = 6
for (AddrSlot = 0; AddrSlot < NumBaseAddr; AddrSlot++)
{
// PCI_CFG_BASE_ADDRESS_0 = 0x10 将0xFFFFFFFF写入 PCI_CFG_BASE_ADDRESS_0 + (4*AddrSlot)
pciConfigOut(BusDevFunc, PCI_CFG_BASE_ADDRESS_0 + (4*AddrSlot),
0xFFFFFFFF, 4);
// 从PCI_CFG_BASE_ADDRESS_0 + (4*AddrSlot)读出数据
AddrDesc = pciConfigIn(BusDevFunc,
PCI_CFG_BASE_ADDRESS_0 + (4*AddrSlot),
4);
// 如果数据是0,没有PCI设备,继续循环搜索
if (AddrDesc == 0) /* unimplemented, stop looking */
continue;
#ifdef PCIDEBUG
printf("Read Base Addr Reg %d = 0x%08xn",AddrSlot,AddrDesc);
#endif
/* 如果AddrDesc的位0是0,表示是Mem方式 */
if ((AddrDesc & 1) == 0)
{
AddrDesc &= 0xFFFFFFF0;
for (i = 0; (AddrDesc & 1) != 1; i++) //查询Mem的大小
AddrDesc = AddrDesc >> 1;
AddrDesc = 1 << i;
if ((unsigned long)AddrDesc < 4096)
AddrDesc = 4096;
#ifdef PCIDEBUG
printf(" PCI Memory space = 0x%x bytes n",AddrDesc);
#endif
for (AddrProg = PCI_MEMORY_START;
AddrProg < LowestMemAddr;
AddrProg += AddrDesc);{{分页}}
pciConfigOut(BusDevFunc, PCI_CFG_BASE_ADDRESS_0 + (4*AddrSlot),
AddrProg, 4);
LowestMemAddr = AddrProg + AddrDesc;
}
else /* I/O 方式*/
{
AddrDesc &= 0xFFFFFFFC;
for (i = 0; (AddrDesc & 1) != 1; i++) //查询I/O空间的大小
AddrDesc = AddrDesc >> 1;
AddrDesc = 1 << i;
#ifdef PCIDEBUG
printf(" PCI I/O space = 0x%x bytes n",AddrDesc);
#endif
for (AddrProg = PCI_IO_REGION_1_START;
AddrProg < LowestIOAddr;
AddrProg += AddrDesc);
pciConfigOut(BusDevFunc, PCI_CFG_BASE_ADDRESS_0 + (4*AddrSlot),
AddrProg, 4);
LowestIOAddr = AddrProg + AddrDesc;
}
}
/*
* Read Min_Gnt(0x3eh) register value and write it to
* the Latency Timer(0xdh) register
*/
Min_Gnt_Val = 0x80;
pciConfigOut(BusDevFunc, PCI_CFG_LATENCY_TIMER, Min_Gnt_Val, 1);
}
2.PCI网卡驱动调用过程
sysNet.c用于初始化系统的网络
文件sysNet.c中void sysNetHwInit(void)定义了,这里以AMD PCI网卡97x为例:
#ifdef INCLUDE_PCI_NETWORK
unsigned char sysEnetAddr [6]; /* 网卡的 MAC 地址 */
char sys97xLoadString[100]; /* 需要为初始化加载的字符串 */
#endif
#ifdef INCLUDE_PCI_NETWORK
STATUS sysIn97xEndBldLoadStr() // 生成网络初始化的字符串
函数sysIn97xEndBldLoadStr()调用pciFindDevice()
STATUS pciFindDevice //用Vendor ID和Device ID查找PCI网卡
(
int VendorID,
int DeviceID,
int index,
int *busDevFunc
)
{
int Device;
int tmpBusDevFunc;
int tmpIndex;
int busNum;
tmpIndex = 0;
for (busNum = MaxBusNum; busNum >= 0; busNum--) //查讯Slot
{
for (Device = 0; Device <= WALNUT_NUM_PCI_SLOTS; Device++)
{
tmpBusDevFunc = (busNum << 16) | (Device << 11);
// 如果指定寄存器中Vendor ID和Device ID正确,赋值给*busDevFunc,返回
if (pciConfigIn(tmpBusDevFunc, PCI_CFG_VENDOR_ID, 2) == VendorID
&& pciConfigIn(tmpBusDevFunc, PCI_CFG_DEVICE_ID, 2) == DeviceID)
{
if (tmpIndex == index)
{
*busDevFunc = tmpBusDevFunc;
return (OK);
}
else /* have a match, but not correct index */
{
tmpIndex++;
}
} } }
return (ERROR); }
sysln97xEndBldLoadStr(..)查找PCI以太网卡,得到PCI网卡的基地址,根据PCI插槽Slot选择正确的中断向量,读网卡的MAC地址,然后调用ln97xEndLoad
STATUS sysln97xEndBldLoadStr ( void )
{
int i;
int intvec;
int intlvl;
ULONG pciMemAddr;
unsigned int busDevFunc;
/*
* 在PCI总线上查找设置第一个AMD设备.
* 如果发现存在,函数pciFindDevice 为busDevFunc赋值
*/
if (pciFindDevice(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_79C97X, 0, &busDevFunc))
return(ERROR);
/*
* 97x的基地址 1 包含PCI存储空间的基地址.
*/
pciMemAddr = pciConfigIn(busDevFunc, PCI_CFG_BASE_ADDRESS_1, 4);
pciMemAddr &= 0xFFFFFFF0;
/*
* 设置PCI定时器反应时间为50 Set latency timer to 50.
*/
pciConfigOut(busDevFunc, PCI_LATENCY_TIMER, 50, 1);
/*
* 每个PCI插槽连接到中断控制器的管脚不一样,中断取决于网卡插在哪一个PCI插槽上.
*/
switch ((busDevFunc & 0x0000F800) >> 11) /* Strip off just the device */
{
case 1 : intvec = INT_VEC_PCI_SLOT3; /* 插槽 3 */
intlvl = INT_LVL_PCI_SLOT3;
break;
case 2 : intvec = INT_VEC_PCI_SLOT2; /* 插槽 2 */
intlvl = INT_LVL_PCI_SLOT2;
break;
case 3 : intvec = INT_VEC_PCI_SLOT1; /* 插槽 1 */
intlvl = INT_LVL_PCI_SLOT1;
break;
case 4 : intvec = INT_VEC_PCI_SLOT0; /* 插槽 0 */
intlvl = INT_LVL_PCI_SLOT0;
break;
default : return(ERROR); /* Not possible, error */
}
/*
* 使能PCI Mem cycles 和 总线 Master 操作
*/
pciConfigOut(busDevFunc, PCI_CFG_COMMAND,
PCI_CMD_MEM_ENABLE | PCI_CMD_MASTER_ENABLE, 2);
/*
* 得到网卡的MAC地址
*/
for (i=0; i<6; i++)
sysEnetAddr = sysInByte(pciMemAddr+APROM01+i);
/*
* 生成初始化字符串,如一下形式:
*
* <devMemAddr>:<devIoAddr>:<pciMemBase>:<vecNum>:<intLvl>:<memAdrs>:
* <memSize>:<memWidth>:<csr3b>:<offset>:<flags>
*
* 这个字符串将在函数muxEndLoad()中加载
*/
sprintf(sys97xLoadString, "0x%x:0x%x:0:%d:%d:0x%x:0:0x%x:0:0:0",
(unsigned int)pciMemAddr, NONE, intvec, intlvl,
NONE,NONE);
return(OK);
}
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