On 23/11/11 15:54, Zvi Vered wrote: > Dear Mr. Welch, > > I'm using busybox 1.19.3 > > This is the latest busybox version. Hmm, that's interesting. It appears that udev converts "!" to "/". In fact, the reverse of this is carried out in the kernel (http://lxr.linux.no/#linux+v3.1.2/lib/kobject.c#L228): int kobject_set_name_vargs(struct kobject *kobj, const char *fmt, va_list vargs) { const char *old_name = kobj->name; char *s; if (kobj->name && !fmt) return 0; kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs); if (!kobj->name) return -ENOMEM; /* ewww... some of these buggers have '/' in the name ... */ while ((s = strchr(kobj->name, '/'))) s[0] = '!'; kfree(old_name); return 0; } This is being triggered because we setup the device names in vme_user like this: for (i = 0; i < VME_DEVS; i++) { int num; switch (type[i]) { case MASTER_MINOR: sprintf(name, "bus/vme/m%%d"); break; case CONTROL_MINOR: sprintf(name, "bus/vme/ctl"); break; case SLAVE_MINOR: sprintf(name, "bus/vme/s%%d"); break; default: err = -EINVAL; goto err_sysfs; break; } num = (type[i] == SLAVE_MINOR) ? i - (MASTER_MAX + 1) : i; image[i].device = device_create(vme_user_sysfs_class, NULL, MKDEV(VME_MAJOR, i), NULL, name, num); if (IS_ERR(image[i].device)) { printk(KERN_INFO "%s: Error creating sysfs device\n", driver_name); err = PTR_ERR(image[i].device); goto err_sysfs; } } A quick trawl of the kernel source shows a few places this is done (namely char/viotape.c and misc/hpilo.c), though it seems to be rather undocumented, the only places I can find this behaviour documented don't seem very authoritative. Greg, is this the proper way to do this? I guess the other question is whether we continue to use these device numbers and this device file layout? Those entries in the Documentation/devices.txt file pre-date git. Last time I checked the code at vmelinux.org was very out of date, I have a feeling it is/was usable with 2.2 and 2.4 kernels (the site is currently off line). The vme_user module doesn't use the same IOCTLs as that driver (and I don't think the approach taken in that driver would every have been suitable to mainline). How about just using simpler names such as "vme_m0"? The vme_user module only currently supports one vme bridge and the device numbers would need to be massaged to properly support more bridges / newer chips with more images (windows) anyway. Do we keep that entry in Documentation/devices.txt, especially since vme_user doesn't use the same interface as the driver at vmelinux.org? What if vmelinux.org has gone away? Martyn > > Thanks, > Zvika. > > ----- Original Message ----- From: "Martyn Welch" <martyn.welch@xxxxxx> > To: "Zvi Vered" <veredz72@xxxxxxxxx> > Cc: <devel@xxxxxxxxxxxxxxxxxxxxxx> > Sent: Wednesday, November 23, 2011 11:37 > Subject: Re: Using vme_tsi148 device driver from user space > > >> Please keep your responses on list... >> >> On 22/11/11 18:17, Zvi Vered wrote: >>> Dear Mr. Welch, >>> >>> I tried the following sequence: >>> >>> 1. insmod vme.ko >>> 2. insmod vme_tsi148.ko >>> 3. insmod vme_user.ko bus=0 >>> 4. mdev -s >>> >>> Upon completion I got the following files in /dev: >>> >>> bus!vme!m0 >>> bus!vme!m1 >>> bus!vme!m2 >>> bus!vme!m3 >>> bus!vme!s0 >>> bus!vme!s1 >>> bus!vme!s2 >>> bus!vme!s3 >>> >>> The file names are strange (the '!' character). >>> >>> According to the documentation the files should be: bus/vme/m0 ... bus/vme/s4 >>> But bus,vme folders are not created. >>> >>> Can you help ? >>> >> >> Just tried it here: >> >> # modprobe vme_user bus=0 >> vme_user: module is from the staging directory, the quality is unknown, you >> have been warned. >> VME User Space Access Driver >> # cd /dev/bus >> # ls >> usb vme >> # cd vme >> # ls -la >> total 0 >> drwxr-xr-x 2 root root 220 Nov 23 09:22 . >> drwxr-xr-x 4 root root 80 Nov 23 09:22 .. >> crw-rw---- 1 root root 221, 8 Nov 23 09:22 ctl >> crw-rw---- 1 root root 221, 0 Nov 23 09:22 m0 >> crw-rw---- 1 root root 221, 1 Nov 23 09:22 m1 >> crw-rw---- 1 root root 221, 2 Nov 23 09:22 m2 >> crw-rw---- 1 root root 221, 3 Nov 23 09:22 m3 >> crw-rw---- 1 root root 221, 4 Nov 23 09:22 s0 >> crw-rw---- 1 root root 221, 5 Nov 23 09:22 s1 >> crw-rw---- 1 root root 221, 6 Nov 23 09:22 s2 >> crw-rw---- 1 root root 221, 7 Nov 23 09:22 s3 >> # >> >> Our user space uses udev, that seems to be creating the directory structure >> correctly. It appears that the version of mdev you are using isn't. Which >> version of busybox are you using? It appears from the busybox website that >> support for the "!" syntax was added to mdev in busybox 1.17.0. >> >> Martyn >> >>> Thanks, >>> Zvika. >>> -- Martyn Welch (Lead Software Engineer) | Registered in England and Wales GE Intelligent Platforms | (3828642) at 100 Barbirolli Square T +44(0)1327322748 | Manchester, M2 3AB E martyn.welch@xxxxxx | VAT:GB 927559189 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
