Hello!
I'm writing a kernel module for AM335x running TI Arago SDK7 kernel on debian FS. I'm trying to set the USB DEVCTL[session] bit in it as part of a set up I'm doing. Everytime I do ioremap and try to read the existing value of that register it causes a seg fault. I am able to ioremap on other registers no problem. In the same module I have had to ioremap USB0MODE register and change the value inside that, and it worked like a charm, no problem.
Here is what I have:
#define USB_REGISTERS_BASE_ADDRESS 0x01C64000
#define DEVCTL_OFFSET 0x460
struct usb_data {
const char* name; /* Name of the register */
unsigned int base; /* Base address of the register unit */
unsigned int offset; /* Offset of the bit/register */
};
static const struct usb_data devctl_reg = {
.name = "DEVCTL",
.base = USB_REGISTERS_BASE_ADDRESS,
.offset = DEVCTL_OFFSET,
};
static void usbmode_setup(const struct usb_data* reg_data, int host)
{
void __iomem* gpio_base;
unsigned int regval;
gpio_base = ioremap(reg_data->base, 0x1000);
if (!gpio_base) {
printk(KERN_ERR "ioremap of USB0 Control Register failed\n");
return;
} else {
printk(KERN_INFO "Successfully Took over %s Registers area at addres: %02x\n", reg_data->name, gpio_base + reg_data->offset);
}
if (host) {
/* Setting host mode */
regval = readl(gpio_base + reg_data->offset);
printk(KERN_INFO "Read Value of %d\n", regval);
printk(KERN_INFO "Writing value 0x80 into the %s register\n", reg_data->name);
writel(0x80, gpio_base + reg_data->offset);
regval = readl(gpio_base + reg_data->offset);
printk(KERN_INFO "Read Value of %d\n", regval);
} else {
/* Setting Device Mode */
}
iounmap(gpio_base);
}
[ 318.240130] Successfully Took over DEVCTL Registers area at addres: e0c6c460 [ 318.247597] Unhandled fault: external abort on non-linefetch (0x1008) at 0xe0c6c460 [ 318.255669] Internal error: : 1008 [#1] PREEMPT ARM [ 318.260806] Modules linked in: usbmod(+) [last unloaded: usbmod] [ 318.267163] CPU: 0 PID: 1709 Comm: insmod Not tainted 3.12.10-svn13 #4 [ 318.274045] task: dd86e040 ti: ddea0000 task.ti: ddea0000 [ 318.279749] PC is at usbmode_setup+0x5c/0xe4 [usbmod] [ 318.285080] LR is at wake_up_klogd+0x54/0x7c [ 318.289581] pc : [<bf00405c>] lr : [<c0073eb0>] psr: 20000013 [ 318.289581] sp : ddea1dc0 ip : ddea1cc0 fp : ddea1ddc [ 318.301670] r10: 00000001 r9 : ddea0000 r8 : bf006000 [ 318.307176] r7 : 00000001 r6 : 00000001 r5 : e0c6c000 r4 : bf00410c [ 318.314049] r3 : e0c6c460 r2 : ddea1cc0 r1 : 00000000 r0 : 00000040 [ 318.320926] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user [ 318.328446] Control: 10c5387d Table: 9def0019 DAC: 00000015 [ 318.334497] Process insmod (pid: 1709, stack limit = 0xddea0240) [ 318.340822] Stack: (0xddea1dc0 to 0xddea2000) [ 318.345420] 1dc0: 00000000 bf00438c bf004258 bf00424c ddea1df4 ddea1de0 bf006048 bf00400c [ 318.354044] 1de0: 00000000 ddea1f48 ddea1e84 ddea1df8 c0008a1c bf00600c 00000000 00000000 [ 318.362663] 1e00: bf00424c 00000000 c008b044 00000001 ddea1e34 ddea1e20 c028db3c c05dc438 [ 318.371279] 1e20: c087b3fc 00000000 ddea1e44 ddea1e38 c0066dd4 c028daf4 ddea1e6c ddea1e48 [ 318.379904] 1e40: c0067e5c c0066dd0 00000000 ddea1e58 ddea1f48 bf004258 bf00424c ddea1f48 [ 318.388521] 1e60: bf004258 bf00424c 00000001 ddf47480 c008b044 00000001 ddea1f44 ddea1e88 [ 318.397138] 1e80: c008d868 c0008934 bf004258 00007fff c008b2c0 000085b0 ddea1ec4 e0c5f000 [ 318.405756] 1ea0: 00000001 bf00424c ddea1edc bf004258 bf004258 bf004294 bf004378 ddea0000 [ 318.414375] 1ec0: ddea1f0c c07a4fbc ddea1fa4 ddea1ed8 c05da520 c00085b4 e0c67000 00000000 [ 318.422991] 1ee0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 318.431608] 1f00: 00000000 00000000 00000000 00000000 00000000 00000000 20000013 000085b0 [ 318.440232] 1f20: b6e55000 b6fb1008 00000080 c0014968 ddea0000 00000000 ddea1fa4 ddea1f48 [ 318.448850] 1f40: c008df34 c008c074 e0c5f000 000085b0 e0c64f08 e0c64d9b e0c673d8 00000390 [ 318.457467] 1f60: 00000410 00000000 00000000 00000000 00000026 00000027 00000010 0000000e [ 318.466086] 1f80: 0000000a 00000000 00000000 b6eb6301 b6fb1dc8 b6fb1d28 00000000 ddea1fa8 [ 318.474704] 1fa0: c00147c0 c008de90 b6eb6301 b6fb1dc8 b6e55000 000085b0 b6fb1008 00000002 [ 318.483328] 1fc0: b6eb6301 b6fb1dc8 b6fb1d28 00000080 00000000 b6fb1008 000085b0 00000000 [ 318.491946] 1fe0: 00000000 bea93bcc b6f68b07 b6ef2fd4 80000010 b6e55000 00000000 00000000 [ 318.500561] Backtrace: [ 318.503162] [<bf004000>] (usbmode_setup+0x0/0xe4 [usbmod]) from [<bf006048>] (transition_start+0x48/0x68 [usbmod]) [ 318.514059] r6:bf00424c r5:bf004258 r4:bf00438c r3:00000000 [ 318.520059] [<bf006000>] (transition_start+0x0/0x68 [usbmod]) from [<c0008a1c>] (do_one_initcall+0xf4/0x154) [ 318.530415] r4:ddea1f48 r3:00000000 [ 318.534206] [<c0008928>] (do_one_initcall+0x0/0x154) from [<c008d868>] (load_module+0x1800/0x1e1c) [ 318.543658] [<c008c068>] (load_module+0x0/0x1e1c) from [<c008df34>] (SyS_init_module+0xb0/0xf4) [ 318.552838] [<c008de84>] (SyS_init_module+0x0/0xf4) from [<c00147c0>] (ret_fast_syscall+0x0/0x30) [ 318.562187] r6:b6fb1d28 r5:b6fb1dc8 r4:b6eb6301 [ 318.567074] Code: e3560000 0a00001b e5943008 e0853003 (e5931000) [ 318.573502] ---[ end trace bb9e578770f42324 ]--- Segmentation fault
My __init calls that function with the right arguments. Here is what I get when I run it:
Am I doing something wrong?
