Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH] Topcliff PHUB: Generate PacketHub driver | Date | Tue, 8 Jun 2010 11:29:48 +0200 |
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On Tuesday 08 June 2010, Masayuki Ohtake wrote: > We are studying your indication. > > My feeling is that this ioctl interface is too > > low-level in general. You only export access to specific > > registers, not to functionality exposed by them. > > The best kernel interfaces are defined in a way that > > is independent of the underlying hardware and > > convert generic commands into device specific commands. > > I have a question. > We don't know 'generic commands' concretely. > Let me know 'generic commands' in detail.
I have not seen the application using the driver, but a better abstraction IMHO would be to take an abstraction you have in your application and move it into the kernel.
I can be more specific if you tell me where to find the source of the application. Generally speaking, you'd transform a function like
/* the function that knows how to do 'this' */ int phub_do_this(int phub_fd, unsigned long arg) { struct pch_phub_req req = { .addr_offset = SOME_ADDR_OFF, }; ioctl(fd, IOCTL_PHUB_READ_REG, &req);
if (req.data & SOME_BITS) return ERROR;
req.addr_offset = ANOTHER_ADDR_OFF; req.data = arg | REALLY_DO_IT_BITMASK;
ioctl(fd, IOCTL_PHUB_WRITE_REG, &req);
return 0; }
into another function that does the same thing but without knowing anything about the registers:
/* the same function on the abstract interface */ int phub_do_this_new(int phub_fd, unsigned long arg) { return ioctl(phub_fd, IOCTL_PHUB_DO_THIS, &arg); }
Arnd
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