我有代码,从我的 PCIe 驱动程序的 probe() 函数调用(大致基于此 post ):
编辑: 基于 Andreas Bombe's响应,我更改了代码以使用 pci_iomap()
,但我仍然遇到系统挂起
static my_pci_dev pci_dev; /* local structure */
static int pci_setup_region(struct pci_dev *dev)
{
int bar = 0;
pci_dev.physical.addr = pci_resource_start(dev, bar);
pci_dev.physical.size = pci_resource_len(dev, bar);
pci_dev.virtual.addr = pci_iomap(dev, bar, pci_dev.physical.size);
if (NULL == pci_dev.virtual.addr) {
return -ENOMEM;
} else {
pci_dev.virtual.size = pci_dev.physical.size;
}
printk(KERN_ALERT "Virtual address: %p", pci_dev.virtual.addr);
if (request_mem_region(pci_dev.physical.addr, pci_dev.physical.size, DEVICE_NAME) == NULL) {
pci_release_resources();
return -EBUSY;
} else {
pci_dev.physical.allocated = 1;
}
/* Test it out! */
printk(KERN_ALERT "Trying to read data.\n");
printk(KERN_ALERT "Copied chip-id data:%08x", ioread8(pci_dev.virtual.addr));
return 0;
}
但是内核只是在调用 ioread8()
时挂起。
我做错了什么吗?还是我需要查看硬件?
下面是 lspci -v
和 cat/proc/iomem
系统干净启动时的输出:
root@socfpga:~# lspci -v
00:00.0 PCI bridge: Altera Corporation Device e000 (rev 01) (prog-if 00 [Normal decode])
Flags: fast devsel
Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
I/O behind bridge: 00000000-00000fff
Memory behind bridge: c0000000-c00fffff
Prefetchable memory behind bridge: 00000000-000fffff
Capabilities: [50] MSI: Enable- Count=1/4 Maskable- 64bit+
Capabilities: [78] Power Management version 3
Capabilities: [80] Express Root Port (Slot-), MSI 00
Capabilities: [100] Virtual Channel
Capabilities: [200] Vendor Specific Information: ID=1172 Rev=0 Len=044 <?>
01:00.0 Multimedia audio controller: Altera Corporation Device e002 (rev 01)
Subsystem: Altera Corporation Device e002
Flags: fast devsel, IRQ 75
Memory at c0000000 (32-bit, non-prefetchable) [disabled] [size=128K]
Capabilities: [50] MSI: Enable- Count=1/4 Maskable- 64bit+
Capabilities: [78] Power Management version 3
Capabilities: [80] Express Endpoint, MSI 00
Capabilities: [100] Virtual Channel
Capabilities: [200] Vendor Specific Information: ID=1172 Rev=0 Len=044 <?>
Kernel modules: test-pci
内存出现[disabled]
:我必须启用它吗?
root@socfpga:~# cat /proc/iomem
00000000-3fffffff : System RAM
00008000-006fa7d3 : Kernel code
00754000-007d8c23 : Kernel data
c0000000-cfffffff : ALTERA PCIE RP MEM
c0000000-c00fffff : PCI Bus 0000:01
c0000000-c001ffff : 0000:01:00.0
d0000000-dfffffff : ALTERA PCIE RP PREF MEM
ff200000-ff20000f : csr
ff200010-ff20008f : vector_slave
ff210000-ff21003f : ff210000.chipidbridge0
ff280000-ff283fff : Cra
ff702000-ff703fff : /soc/ethernet@ff702000
ff704000-ff704fff : /soc/dwmmc0@ff704000
ff705000-ff705fff : ff705000.spi
ffa00000-ffa00fff : ff705000.spi
ffb40000-ffb4fffe : /soc/usb@ffb40000
ffc00000-ffc00fff : c_can_platform
ffc02000-ffc0201f : serial
ffc04000-ffc04fff : /soc/i2c@ffc04000
ffd02000-ffd02fff : /soc/wd@ffd02000
ffe01000-ffe01fff : /soc/amba/pdma@ffe01000
fff00000-fff00fff : fff00000.spi
ffff0000-ffffffff : /soc/sram@ffff0000
root@socfpga:~#
最佳答案
您一定要启用它。这些是基本步骤:
pci_enable_device(dev);
pci_request_regions(dev, "driver/device name");
bar0 = pci_iomap(dev, 0, 0);
x = ioread(bar0 + offset); /* there you are */
所有 pci_*
调用都需要进行错误检查。如果设备需要执行 DMA,您还需要调用 pci_set_master
和 pci_set_dma_mask
。
详细来说,绕过 PCI 内核代码并直接对 BAR 进行 ioremapping 可能在很久以前就已经奏效了。我不确定它在当前代码中是否合法,但它肯定是不可取的。
关于linux - 我是否需要 "enable"Linux 3.12 驱动程序中的 PCIe 内存区域?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23414288/