Linux Kernel 如何管理 PCIe 设备
假设已经阅读过 【原创】Linux PCI 驱动框架分析（二）
在 driver/pci 主要文件的内容:
| File | blank | comment | code | explanation |
|---|---|---|---|---|
| pci.c | 950 | 1955 | 3667 | capability list 的封装 |
| probe.c | 543 | 631 | 2137 | |
| setup-bus.c | 333 | 373 | 1536 | |
| pci-sysfs.c | 244 | 150 | 1170 | |
| pci-driver.c | 283 | 331 | 1045 | |
| msi.c | 258 | 276 | 1045 | |
| pci-acpi.c | 205 | 175 | 989 | |
| pcie/aer.c | 214 | 229 | 961 | |
| pcie/aspm.c | 191 | 245 | 941 | |
| iov.c | 189 | 177 | 725 | |
| p2pdma.c | 164 | 240 | 601 | |
| pci.h | 97 | 64 | 532 | |
| vpd.c | 101 | 85 | 467 | |
| pcie/aer_inject.c | 67 | 18 | 460 | |
| slot.c | 0 | 0 | 379 | |
| access.c | 访问配置空间的函数封装 | |||
| ecam.c | ecam 的支持 |
其实，内核中处理 PCIe 的代码并不多发。
关键结构体
pci_dev: 将配置空间的信息会保存一些到里面pci_bus: 有点像是在描述 pci bridge 啊，从pci_scan_bridge_extend看，虽然 bridge 会形成一个 pci bus，但是这个 bus 的属性是通过pci_bus描述的pci_driver: 包含一个device_driverpci_host_bridgepci_slot
scan 的过程
pci_scan_child_buspci_scan_child_bus_extendpci_scan_bridge_extend: If it’s a bridge, configure it and scan the bus behind it.pci_scan_slotpci_scan_single_device-pci_get_slot-pci_scan_devicepci_alloc_dev: 分配一个struct pci_devpci_setup_device:pci_setup_device- Fill in class and map information of a device
probe 的过程
使用 e1000 的为例:
static struct pci_driver e1000_driver = {
.name = e1000_driver_name,
.id_table = e1000_pci_tbl,
.probe = e1000_probe,
.remove = e1000_remove,
.driver = {
.pm = &e1000_pm_ops,
},
.shutdown = e1000_shutdown,
.err_handler = &e1000_err_handler
};
#0 e1000_probe (pdev=0xffff888003699000, ent=0xffffffff822e2f40 <e1000_pci_tbl+640>) at drivers/net/ethernet/intel/e1000e/netdev.c:7408
#1 0xffffffff814abf6d in local_pci_probe (_ddi=_ddi@entry=0xffffc90000013d80) at drivers/pci/pci-driver.c:323
#2 0xffffffff814ad343 in pci_call_probe (id=<optimized out>, dev=0xffff888003699000, drv=<optimized out>) at drivers/pci/pci-driver.c:391
#3 __pci_device_probe (pci_dev=0xffff888003699000, drv=<optimized out>) at drivers/pci/pci-driver.c:416
#4 pci_device_probe (dev=0xffff8880036990c8) at drivers/pci/pci-driver.c:459
#5 0xffffffff81722350 in call_driver_probe (drv=0xffffffff829f3fd8 <e1000_driver+120>, drv=0xffffffff829f3fd8 <e1000_driver+120>, dev=0xffff8880036990c8) at drivers/base/dd.c:542
#6 really_probe (drv=0xffffffff829f3fd8 <e1000_driver+120>, dev=0xffff8880036990c8) at drivers/base/dd.c:621
#7 really_probe (dev=0xffff8880036990c8, drv=0xffffffff829f3fd8 <e1000_driver+120>) at drivers/base/dd.c:566
#8 0xffffffff817224fd in __driver_probe_device (drv=drv@entry=0xffffffff829f3fd8 <e1000_driver+120>, dev=dev@entry=0xffff8880036990c8) at drivers/base/dd.c:752
#9 0xffffffff81722579 in driver_probe_device (drv=drv@entry=0xffffffff829f3fd8 <e1000_driver+120>, dev=dev@entry=0xffff8880036990c8) at drivers/base/dd.c:782
#10 0xffffffff8172288a in __driver_attach (data=0xffffffff829f3fd8 <e1000_driver+120>, dev=0xffff8880036990c8) at drivers/base/dd.c:1141
#11 __driver_attach (dev=0xffff8880036990c8, data=0xffffffff829f3fd8 <e1000_driver+120>) at drivers/base/dd.c:1093
#12 0xffffffff817204a3 in bus_for_each_dev (bus=<optimized out>, start=start@entry=0x0 <fixed_percpu_data>, data=data@entry=0xffffffff829f3fd8 <e1000_driver+120>, fn=fn@entry=0xffffffff81722830 <__driver_attach>) at drivers/base/bus.c:301
#13 0xffffffff81721d05 in driver_attach (drv=drv@entry=0xffffffff829f3fd8 <e1000_driver+120>) at drivers/base/dd.c:1158
#14 0xffffffff81721662 in bus_add_driver (drv=drv@entry=0xffffffff829f3fd8 <e1000_driver+120>) at drivers/base/bus.c:618
#15 0xffffffff817230f7 in driver_register (drv=0xffffffff829f3fd8 <e1000_driver+120>) at drivers/base/driver.c:171
#16 0xffffffff81000dbf in do_one_initcall (fn=0xffffffff8300519c <e1000_init_module>) at init/main.c:1298
#17 0xffffffff82fc5405 in do_initcall_level (command_line=0xffff888003546040 "root", level=6) at ./include/linux/compiler.h:234
#18 do_initcalls () at init/main.c:1387
#19 do_basic_setup () at init/main.c:1406
#20 kernel_init_freeable () at init/main.c:1613
#21 0xffffffff81c9e851 in kernel_init (unused=<optimized out>) at init/main.c:1502
#22 0xffffffff810019a2 in ret_from_fork () at arch/x86/entry/entry_64.S:298
#23 0x0000000000000000 in ?? ()
- PCI drivers “discover” PCI devices in a system via
pci_register_driver(). 1 pci_bus::probe和pci_driver::probe的关系pci_driver::probe中完成的工作
Once the driver knows about a PCI device and takes ownership, the driver generally needs to perform the following initialization: 1
- Enable the device
- Request MMIO/IOP resources
- Set the DMA mask size (for both coherent and streaming DMA)
- Allocate and initialize shared control data (
pci_allocate_coherent())- Access device configuration space (if needed)
- Register IRQ handler (
request_irq())- Initialize non-PCI (i.e. LAN/SCSI/etc parts of the chip)
- Enable DMA/processing engines