/* PCI device */
struct pci_device {
char *name;u_int vendor_id,product_id;int device,function,irq;void *priv_data;
/* Parent bus */
struct pci_bus *pci_bus;pci_init_t init;pci_reg_read_t read_register;pci_reg_write_t write_register;struct pci_device *next,**pprev;
};
/* PCI bus */struct pci_bus {char *name;m_uint32_t pci_addr;/* Bus number */int bus;/* PCI device list on this bus */struct pci_device *dev_list;/* PCI bridges to access other busses */struct pci_bridge *bridge_list;};PCI總線的數據結構/* PCI bridge */struct pci_bridge {int pri_bus; /* Primary Bus */int sec_bus; /* Secondary Bus */int sub_bus; /* Subordinate Bus */int skip_bus_check;/* Bus configuration register */m_uint32_t cfg_reg_bus;/* PCI bridge device */struct pci_device *pci_dev;/* Secondary PCI bus */struct pci_bus *pci_bus;/* Fallback handlers to read/write config registers */pci_reg_read_t fallback_read;pci_reg_write_t fallback_write;struct pci_bridge *next,**pprev;};struct pci_device *pci_bridge_create_dev(struct pci_bus *pci_bus,char *name,u_int vendor_id,u_int product_id,int device,int function,struct pci_bus *sec_bus,pci_reg_read_t fallback_read,pci_reg_write_t fallback_write)pci_bridge_create_dev這個函數的功能是創建PCI橋設備,sec_bus這個入參指向下一級總線.
比如DEC21050橋芯片模擬就調用這個函數,
int dev_dec21050_init(struct pci_bus *pci_bus,int pci_device,struct pci_bus *sec_bus){struct pci_device *dev;dev = pci_bridge_create_dev(pci_bus,"dec21050",PCI_VENDOR_DEC,PCI_PRODUCT_DEC_21050,pci_device,0,sec_bus,NULL,NULL);return((dev != NULL) ? 0 : -1);}/* Add a PCI device */struct pci_device *pci_dev_add(struct pci_bus *pci_bus,char *name,u_int vendor_id,u_int product_id,int device,int function,int irq,void *priv_data,pci_init_t init,pci_reg_read_t read_register,pci_reg_write_t write_register)pci_dev_add這個函數創建了PCI設備.比如struct am79c971_data *dev_am79c971_init(vm_instance_t *vm,char *name,int interface_type,struct pci_bus *pci_bus,int pci_device,int irq){struct am79c971_data *d;struct pci_device *pci_dev;struct vdevice *dev;/* Allocate the private data structure for AM79C971 */if (!(d = malloc(sizeof(*d)))) {fprintf(stderr,"%s (AM79C971): out of memory ",name);return NULL;
}memset(d,0,sizeof(*d));memcpy(d->mii_regs[0],mii_reg_values,sizeof(mii_reg_values));pthread_mutex_init(&d->lock,NULL);/* Add as PCI device */pci_dev = pci_dev_add(pci_bus,name,AM79C971_PCI_VENDOR_ID,AM79C971_PCI_PRODUCT_ID,pci_device,0,irq,d,NULL,pci_am79c971_read,pci_am79c971_write);if (!pci_dev) {fprintf(stderr,"%s (AM79C971): unable to create PCI device. ",name);goto err_pci_dev;}
AM79C971的讀寫函數被註冊爲pci_am79c971_read,pci_am79c971_write
實現如下:
static m_uint32_t pci_am79c971_read(cpu_gen_t *cpu,struct pci_device *dev,
int reg)
{
struct am79c971_data *d = dev->priv_data;
#if DEBUG_PCI_REGS
AM79C971_LOG(d,"read PCI register 0x%x/n",reg);
#endif
switch (reg) {
case 0x00:
return((AM79C971_PCI_PRODUCT_ID << 16) | AM79C971_PCI_VENDOR_ID);
case 0x08:
return(0x02000002);
case PCI_REG_BAR1:
return(d->dev->phys_addr);
default:
return(0);
}
}
再比如
/*
* pci_ap1011_read()
*
* Read a PCI register.
*/
static m_uint32_t pci_ap1011_read(cpu_gen_t *cpu,struct pci_device *dev,
int reg)
{
switch (reg) {
case 0x08:
return(0x06040000);
case 0x34:
return(0x00000040);
case 0x40:
return(0x00210008);
case 0x44:
return(0x00000020);
case 0x48:
return(0x000000C0);
default:
return(0);
}
}
這些實現函數就是模擬寄存器響應的實現.
那麼什麼時候會觸發寄存器的訪問?
是通過pci_dev_data_handler來處理的,這個函數會調用各個設備掛接在數據結構上的
讀寫函數來實現訪問
/** Handle the data register access.** The address of requested register is first written at address 0xcf8* (with pci_dev_addr_handler).** The data is read/written at address 0xcfc.*/void pci_dev_data_handler(cpu_gen_t *cpu,struct pci_bus *pci_bus,u_int op_type,int swap,m_uint64_t *data){struct pci_device *dev;int bus,device,function,reg;if (op_type == MTS_READ)*data = 0x0;/** http://www.mega-tokyo.com/osfaq2/index.php/PciSectionOfPentiumVme** 31 : Enable Bit* 30 - 24 : Reserved* 23 - 16 : Bus Number* 15 - 11 : Device Number* 10 - 8 : Function Number* 7 - 2 : Register Number* 1 - 0 : always 00*/bus = GET_PCI_ADDR(16,0xff);device = GET_PCI_ADDR(11,0x1f);function = GET_PCI_ADDR(8,0x7);reg = GET_PCI_ADDR(0,0xff);/* Find the corresponding PCI device */dev = pci_dev_lookup(pci_bus,bus,device,function);#if DEBUG_PCIif (op_type == MTS_READ) {cpu_log(cpu,"PCI","read request at pc=0x%llx: ""bus=%d,device=%d,function=%d,reg=0x%2.2x ",cpu_get_pc(cpu), bus, device, function, reg);} else {cpu_log(cpu,"PCI","write request (data=0x%8.8x) at pc=0x%llx: ""bus=%d,device=%d,function=%d,reg=0x%2.2x ",pci_swap(*data,swap), cpu_get_pc(cpu),bus, device, function, reg);}#endifif (!dev) {if (op_type == MTS_READ) {cpu_log(cpu,"PCI","read request for unknown device at pc=0x%llx ""(bus=%d,device=%d,function=%d,reg=0x%2.2x). ",cpu_get_pc(cpu), bus, device, function, reg);} else {cpu_log(cpu,"PCI","write request (data=0x%8.8x) for unknown device ""at pc=0x%llx (bus=%d,device=%d,function=%d,reg=0x%2.2x). ",pci_swap(*data,swap), cpu_get_pc(cpu),bus, device, function, reg);}/* Returns an invalid device ID */if ((op_type == MTS_READ) && (reg == PCI_REG_ID))*data = 0xffffffff;} else {if (op_type == MTS_WRITE) {if (dev->write_register != NULL)dev->write_register(cpu,dev,reg,pci_swap(*data,swap));} else {if (reg == PCI_REG_ID)*data = pci_swap((dev->product_id << 16) | dev->vendor_id,swap);else {if (dev->read_register != NULL)*data = pci_swap(dev->read_register(cpu,dev,reg),swap);}}}}dev_c2600_pci_init:d->dev.handler = dev_c2600_pci_access;dev_c2600_pci_access:switch(offset) {case 0x500:pci_dev_addr_handler(cpu,d->bus,op_type,FALSE,data);break;case 0x504:pci_dev_data_handler(cpu,d->bus,op_type,FALSE,data);break;PCI的處理最後通過vm_bind_device綁定到VM對象上
也就是說vm->dev_array[i].handler(比如dev_c2600_pci_access)可以訪問到PCI處理函數
最後是 dev_access_fast 這個通用訪問函數調用了處理函數
/* device access function */
static forced_inline
void *dev_access_fast(cpu_gen_t *cpu,u_int dev_id,m_uint32_t offset,
u_int op_size,u_int op_type,m_uint64_t *data)
{
struct vdevice *dev = cpu->vm->dev_array[dev_id];
if (unlikely(!dev)) {
cpu_log(cpu,"dev_access_fast","null handler (dev_id=%u,offset=0x%x)/n",
dev_id,offset);
return NULL;
}
#if DEBUG_DEV_PERF_CNT
cpu->dev_access_counter++;
#endif
return(dev->handler(cpu,dev,offset,op_size,op_type,data));
}
mips64_mts64_access
mips64_mts32_access
ppc32_mem_access
這三個函數調用了dev_access_fast
以ppc32_mem_access(訪問DCACHE時的等效宏定義是PPC32_MEM_DACCESS)爲例,看有哪些函數調用了
ppc32_lbz
ppc32_lhz
ppc32_lwz
ppc32_lwbr等內存指令
另外一處調用在ppc32_mem_lookup(虛擬地址查找)
掛接在cpu->mem_op_lookup = ppc32_mem_lookup;
有ppc32_exec_fetch等函數使用了cpu->mem_op_lookup.
還有一些問題:
1.怎麼知道哪些地址對應哪個訪問函數?