我正在使用Raspberry PI 4B进行嵌入式Linux培训，为了创建I2C总线驱动程序，我需要访问硬件寄存器。问题是，当我试图阅读其中任何一本时，我会得到"；未处理的故障：0xf08c5000处的未知3(0x203(；。
这是我用来读取寄存器的代码：
void i2cHandler_init(void)
{
const u32 rpiPeriphBase = 0xfe000000;
const u32 rpiGpioOffset = 0x200000;
const void *rpiGpioAddress = rpiPeriphBase + rpiGpioOffset;
__iomem u32 *ioMemory;
ioMemory = ioremap(rpiGpioAddress, 0x40 * 8);
pr_info("%s: rpiGpioAddress = 0x%xrn", __func__, rpiGpioAddress);
pr_info("%s: ioMemory = 0x%xrn", __func__, ioMemory);
pr_info("%s: Register value = 0x%xrn", __func__, readl(ioMemory));
if(ioMemory != NULL)
iounmap(ioMemory);
}
是的，我试图在这里读取GPIO GPFSEL0寄存器，但将偏移量更改为读取I2C控制寄存器不会改变任何内容。内核日志输出如下：
[ 1467.677279] i2cHandler_init: rpiGpioAddress = 0xfe200000
[ 1467.677289] i2cHandler_init: ioMemory = 0xf08c5000
[ 1467.677308] 8<--- cut here ---
[ 1467.677325] Unhandled fault: unknown 3 (0x203) at 0xf08c5000
[ 1467.677340] pgd = f812a8c9
[ 1467.677353] [f08c5000] *pgd=80000000007003, *pmd=2ff5b003, *pte=c00ffffe200713
[ 1467.677385] Internal error: : 203 [#1] SMP ARM
[ 1467.677400] Modules linked in: rpi_driver_I2C(O+) rfcomm cmac algif_hash aes_arm_bs crypto_simd cryptd algif_skcipher af_alg bnep hci_uart btbcm bluetooth ecdh_generic ecc spidev snd_soc_hdmi_codec 8021q garp stp llc brcmfmac brcmutil v3d cfg80211 gpu_sched rfkill raspberrypi_hwmon i2c_brcmstb vc4 spi_bcm2835 cec bcm2835_codec(C) bcm2835_v4l2(C) bcm2835_isp(C) v4l2_mem2mem bcm2835_mmal_vchiq(C) videobuf2_dma_contig videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common vc_sm_cma(C) drm_kms_helper videodev snd_bcm2835(C) snd_soc_core mc snd_compress snd_pcm_dmaengine snd_pcm rpivid_mem snd_timer snd syscopyarea sysfillrect sysimgblt fb_sys_fops uio_pdrv_genirq uio nvmem_rmem i2c_dev drm drm_panel_orientation_quirks backlight fuse ip_tables x_tables ipv6 [last unloaded: rpi_driver_I2C]
[ 1467.677744] CPU: 0 PID: 2059 Comm: insmod Tainted: G C O 5.15.32-v7l+ #1538
[ 1467.677764] Hardware name: BCM2711
[ 1467.677775] PC is at i2cHandler_init+0xc4/0x178 [rpi_driver_I2C]
[ 1467.677808] LR is at irq_work_queue+0x14/0x2c
[ 1467.677833] pc : [<bf3fe464>] lr : [<c0358054>] psr: 60000013
[ 1467.677846] sp : c3e57d68 ip : 00000000 fp : c3e57d7c
[ 1467.677859] r10: c1205048 r9 : bf400380 r8 : 00000000
[ 1467.677871] r7 : 00000002 r6 : bf3fe5a8 r5 : c1205048 r4 : f08c5000
[ 1467.677884] r3 : 3391a86e r2 : 3391a86e r1 : 00000027 r0 : 00000029
[ 1467.677898] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 1467.677914] Control: 30c5383d Table: 041e1e40 DAC: fffffffd
[ 1467.677926] Register r0 information: non-paged memory
[ 1467.677943] Register r1 information: non-paged memory
[ 1467.677958] Register r2 information: non-paged memory
[ 1467.677973] Register r3 information: non-paged memory
[ 1467.677988] Register r4 information: 0-page vmalloc region starting at 0xf08c5000 allocated at i2cHandler_init+0x80/0x178 [rpi_driver_I2C]
[ 1467.678024] Register r5 information: non-slab/vmalloc memory
[ 1467.678041] Register r6 information: 4-page vmalloc region starting at 0xbf3fe000 allocated at load_module+0xb94/0x2840
[ 1467.678069] Register r7 information: non-paged memory
[ 1467.678084] Register r8 information: NULL pointer
[ 1467.678099] Register r9 information: 4-page vmalloc region starting at 0xbf3fe000 allocated at load_module+0xb94/0x2840
[ 1467.678124] Register r10 information: non-slab/vmalloc memory
[ 1467.678140] Register r11 information: non-slab/vmalloc memory
[ 1467.678155] Register r12 information: NULL pointer
[ 1467.678170] Process insmod (pid: 2059, stack limit = 0x91bbcd6e)
[ 1467.678185] Stack: (0xc3e57d68 to 0xc3e58000)
[ 1467.678199] 7d60: bf400380 c1205048 c3e57d8c c3e57d80 bf3fe5fc bf3fe3ac
[ 1467.678217] 7d80: c3e57d9c c3e57d90 bf3fe5cc bf3fe5e4 c3e57e14 c3e57da0 c02021c4 bf3fe5b4
[ 1467.678234] 7da0: c0439ca0 c0bd5bf4 c1401180 00000000 c3e57dd4 c3e57dc0 c0bd5bf4 c029f244
[ 1467.678251] 7dc0: c1401180 c043ade4 c3e57e14 c3e57dd8 c043ade4 c03f4518 c041c20c c043997c
[ 1467.678269] 7de0: 00000008 c02d056c f097d000 3391a86e 00000002 bf400380 00000002 c3c36d80
[ 1467.678286] 7e00: 00000002 c4ad01c8 c3e57e3c c3e57e18 c02d058c c0202180 c3e57e3c c3e57e28
[ 1467.678303] 7e20: c041c394 c3e57f30 00000002 c4ad0180 c3e57f14 c3e57e40 c02d2dac c02d0544
[ 1467.678320] 7e40: bf40038c 00007fff bf400380 c02cf240 c1205048 c0e3b448 c0e3b460 c0e3b3f0
[ 1467.678337] 7e60: bf0c609a c0e3b4b0 c0c03df0 c3e57f30 bf400594 c4dc6418 bf4003c8 c4ad0188
[ 1467.678354] 7e80: c0e3afcc 00000001 00000000 c0efea84 c0ee67d0 00000000 00000000 00000000
[ 1467.678371] 7ea0: 00000000 00000000 6e72656b 00006c65 00000000 00000000 00000000 00000000
[ 1467.678388] 7ec0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 1467.678405] 7ee0: 00000000 3391a86e c3e57f2c c1205048 00000000 0002de04 00000003 c0200244
[ 1467.678423] 7f00: c3e56000 0000017b c3e57fa4 c3e57f18 c02d33b0 c02d0900 c3e57f2c 7fffffff
[ 1467.678439] 7f20: 00000000 00000002 c3e57f24 f097d000 f097db9e f097e5c0 f097d000 000033ac
[ 1467.678456] 7f40: f097ff9c f097fea8 f097f3a0 00003000 000036e0 00002018 00003aab 00000000
[ 1467.678474] 7f60: 00000000 00000000 00002008 00000017 00000018 00000010 0000000d 0000000a
[ 1467.678491] 7f80: 00000000 3391a86e 00000000 00000002 f9957800 0000017b 00000000 c3e57fa8
[ 1467.678508] 7fa0: c0200040 c02d32f4 00000000 00000002 00000003 0002de04 00000000 b6f68074
[ 1467.678535] 7fc0: 00000000 00000002 f9957800 0000017b 00e9acc8 00000002 bee367d4 00000000
[ 1467.678554] 7fe0: bee36600 bee365f0 00023bc0 b6c459e0 60000010 00000003 00000000 00000000
[ 1467.678568] Backtrace:
[ 1467.678582] [<bf3fe3a0>] (i2cHandler_init [rpi_driver_I2C]) from [<bf3fe5fc>] (mainCycle_init+0x24/0x38 [rpi_driver_I2C])
[ 1467.678632] r5:c1205048 r4:bf400380
[ 1467.678643] [<bf3fe5d8>] (mainCycle_init [rpi_driver_I2C]) from [<bf3fe5cc>] (init_module+0x24/0x30 [rpi_driver_I2C])
[ 1467.678687] [<bf3fe5a8>] (init_module [rpi_driver_I2C]) from [<c02021c4>] (do_one_initcall+0x50/0x244)
[ 1467.678726] [<c0202174>] (do_one_initcall) from [<c02d058c>] (do_init_module+0x54/0x23c)
[ 1467.678760] r8:c4ad01c8 r7:00000002 r6:c3c36d80 r5:00000002 r4:bf400380
[ 1467.678776] [<c02d0538>] (do_init_module) from [<c02d2dac>] (load_module+0x24b8/0x2840)
[ 1467.678807] r6:c4ad0180 r5:00000002 r4:c3e57f30
[ 1467.678824] [<c02d08f4>] (load_module) from [<c02d33b0>] (sys_finit_module+0xc8/0xfc)
[ 1467.678857] r10:0000017b r9:c3e56000 r8:c0200244 r7:00000003 r6:0002de04 r5:00000000
[ 1467.678876] r4:c1205048
[ 1467.678892] [<c02d32e8>] (sys_finit_module) from [<c0200040>] (ret_fast_syscall+0x0/0x1c)
[ 1467.678925] Exception stack(0xc3e57fa8 to 0xc3e57ff0)
[ 1467.678943] 7fa0: 00000000 00000002 00000003 0002de04 00000000 b6f68074
[ 1467.678969] 7fc0: 00000000 00000002 f9957800 0000017b 00e9acc8 00000002 bee367d4 00000000
[ 1467.678986] 7fe0: bee36600 bee365f0 00023bc0 b6c459e0
[ 1467.679007] r7:0000017b r6:f9957800 r5:00000002 r4:00000000
[ 1467.679030] Code: e1a02004 e30f0360 e34b0f3f eb5f37d6 (e5942000)
[ 1467.679052] ---[ end trace b887a2abb18bba14 ]---
此外，我确信外围设备的基本地址是正确的；sudo cat/proc/iomem"；看起来像这样：
00000000-3b3fffff : System RAM
00008000-00ffffff : Kernel code
01200000-013ef203 : Kernel data
40000000-7fffffff : System RAM
fd500000-fd50930f : fd500000.pcie pcie@7d500000
fd580000-fd58ffff : fd580000.ethernet ethernet@7d580000
fd580e14-fd580e1c : unimac-mdio.-19
fe004000-fe00401f : fe004000.txp txp@7e004000
fe007000-fe007aff : fe007000.dma dma@7e007000
fe007b00-fe007eff : fe007b00.dma dma@7e007b00
fe00a000-fe00a023 : fe100000.watchdog watchdog@7e100000
fe00b840-fe00b87b : fe00b840.mailbox mailbox@7e00b840
fe00b880-fe00b8bf : fe00b880.mailbox mailbox@7e00b880
fe100000-fe100113 : fe100000.watchdog watchdog@7e100000
fe101000-fe102fff : fe101000.cprman cprman@7e101000
fe104000-fe104027 : fe104000.rng rng@7e104000
**fe200000-fe2000b3 : fe200000.gpio gpio@7e200000**
fe201000-fe2011ff : serial@7e201000
fe201000-fe2011ff : fe201000.serial serial@7e201000
fe204000-fe2041ff : fe204000.spi spi@7e204000
fe206000-fe2060ff : fe206000.pixelvalve pixelvalve@7e206000
fe207000-fe2070ff : fe207000.pixelvalve pixelvalve@7e207000
fe20a000-fe20a0ff : fe20a000.pixelvalve pixelvalve@7e20a000
fe215000-fe215007 : fe215000.aux aux@7e215000
fe216000-fe2160ff : fe216000.pixelvalve pixelvalve@7e216000
fe300000-fe3000ff : fe300000.mmcnr mmcnr@7e300000
fe340000-fe3400ff : fe340000.mmc mmc@7e340000
fe400000-fe407fff : fe400000.hvs hvs@7e400000
fec00000-fec03fff : fec00000.v3d hub
fec04000-fec07fff : fec00000.v3d core0
fec11000-fec1101f : fe100000.watchdog watchdog@7e100000
fec12000-fec120ff : fec12000.pixelvalve pixelvalve@7ec12000
fef00000-fef0000f : fef00000.clock clock@7ef00000
fef00b00-fef00dff : fef04500.i2c auto-i2c
fef04500-fef045ff : fef04500.i2c bsc
fef05b00-fef05dff : fef09500.i2c auto-i2c
fef09500-fef095ff : fef09500.i2c bsc
600000000-63fffffff : pcie@7d500000
600000000-6000fffff : PCI Bus 0000:01
600000000-600000fff : 0000:01:00.0
600000000-600000fff : xhci-hcd
Raspbeerry PI在Raspbian操作系统32位版本下工作。内核版本为5.15.32-v7l+。我尝试了从不同来源找到的不同基地址：
- 0x20000000-ioremap返回0
- 0x3e00000-ioremap有效，没有错误，但那里的值没有意义，用这个基地址写入根本不会引起任何反应
- 0x7e00000-ioremap返回0
- 0x7e00000没有ioremap-错误"；无法处理虚拟地址处的内核分页请求&">
根据不同的论坛主题和示例，我的代码应该可以工作，但事实并非如此，所以我现在没有想法。有人有什么想法吗？这是我的错误还是其他什么问题？
问题已解决。我的代码似乎没有什么问题，64位操作系统起到了帮助作用。我实际上并没有安装64位系统；arm_ 64bit＝1"；到my/boot/config.txt，并更新了所有包，因为这只是为了测试目的，但这很有效。