Re: OFWBUS: How does autoconfiguration work?
On Tue, 2020-02-04 at 19:09 +0530, Niteesh wrote: > I am working on an operating systems project at my university, which > currently > uses lazy driver initialization i.e. that is the drivers initialize the > hardware only > during the first invocation, for example, the UART hardware is initialized > only during the first call to output_char. > > Currently, we have multiple BSP's to support different variants even though > they are quite similar. For example, we have two BSPs to support BeagleBone > Black > and white. We are trying to avoid this by using device tree files. Our goal > is to parse the > DTB at boot time and call all the registered drivers to initialize the > hardware. By registered > drivers, I mean drivers which are statically linked to executable. > > I am trying to add a system, which will parse the DTB files and initialize > them by calling > the appropriate drivers. I want a system similar to FreeBSD or Linux > a probe and attach method for device drivers. It doesn't have to be as > complex as FreeBSD > but a simple one will do. > > If you have any other questions please let me know :) > > Thanks, > Niteesh > I don't think there is anything much in the freebsd code that will help you with that. The book "The Design and Implementation of the FreeBSD Operating System 2nd ed." describes the freebsd autoconfiguration mechanisms. Those mechanisms are designed to solve problems a lot more complex than parsing a simple hierarchical dtb to find active devices, it supports a mix of buses that can identify the devices on the bus (USB, PCI), buses that are described with metadata (ACPI, fdt simplebus, ISA bus with PNP data), and drivers that can just force a bus to adopt them by using an identify() method. Resource management (interrupts and mmio ranges, mostly) are also part of the scheme. FDT data adds another wrinkle by creating cross-hierarchy links between devices using phandles, and there are sideband subsystems in freebsd to handle that stuff separately from the normal hiearchical parent/child bus relationships. There just isn't much that can reasonably be separated out and used in another project, I think. -- Ian ___ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
Re: OFWBUS: How does autoconfiguration work?
I am working on an operating systems project at my university, which currently uses lazy driver initialization i.e. that is the drivers initialize the hardware only during the first invocation, for example, the UART hardware is initialized only during the first call to output_char. Currently, we have multiple BSP's to support different variants even though they are quite similar. For example, we have two BSPs to support BeagleBone Black and white. We are trying to avoid this by using device tree files. Our goal is to parse the DTB at boot time and call all the registered drivers to initialize the hardware. By registered drivers, I mean drivers which are statically linked to executable. I am trying to add a system, which will parse the DTB files and initialize them by calling the appropriate drivers. I want a system similar to FreeBSD or Linux a probe and attach method for device drivers. It doesn't have to be as complex as FreeBSD but a simple one will do. If you have any other questions please let me know :) Thanks, Niteesh On Sun, Feb 2, 2020 at 9:07 PM Ian Lepore wrote: > On Sun, 2020-02-02 at 10:02 +0530, Niteesh wrote: > > I couldn't find anything useful for me, I need information about how the > > hardware autoconfiguration works, not autoconf. > > > > Then maybe you need to provide more details about what you're doing, > what you've tried that isn't working, or something. I couldn't make > any sense out of your original question. > > -- Ian > > ___ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
Re: OFWBUS: How does autoconfiguration work?
On Sun, 2020-02-02 at 10:02 +0530, Niteesh wrote: > I couldn't find anything useful for me, I need information about how the > hardware autoconfiguration works, not autoconf. > Then maybe you need to provide more details about what you're doing, what you've tried that isn't working, or something. I couldn't make any sense out of your original question. -- Ian ___ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
Re: OFWBUS: How does autoconfiguration work?
I couldn't find anything useful for me, I need information about how the hardware autoconfiguration works, not autoconf. On Sun, Feb 2, 2020 at 12:24 AM Clay Daniels wrote: > Take a look at the Porter's Handbook: > > > https://docs.freebsd.org/doc/7.4-RELEASE/usr/share/doc/en/books/porters-handbook/using-autotools.html > > On Sat, Feb 1, 2020 at 8:56 AM Niteesh wrote: > >> I am interested in adding autoconfiguration to one of my projects. >> The current drivers use lazy initialization, for example, the UART >> drivers initialize the hardware only during their first invocation. >> >> I would like to add a subsystem, that will read the DTB and call >> the appropriate drivers. >> >> I want to know how it is implemented in FreeBSD, I took a look at the >> code, but I am still couldn't figure out, when does FreeBSD start to >> parse the DTB, how does it fill up the device struct and few more. >> >> Can someone please explain how all this works with reference to code >> or point me to some documentation? >> >> Thanks, >> Niteesh >> ___ >> freebsd-current@freebsd.org mailing list >> https://lists.freebsd.org/mailman/listinfo/freebsd-current >> To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org >> " >> > ___ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
Re: OFWBUS: How does autoconfiguration work?
Take a look at the Porter's Handbook: https://docs.freebsd.org/doc/7.4-RELEASE/usr/share/doc/en/books/porters-handbook/using-autotools.html On Sat, Feb 1, 2020 at 8:56 AM Niteesh wrote: > I am interested in adding autoconfiguration to one of my projects. > The current drivers use lazy initialization, for example, the UART > drivers initialize the hardware only during their first invocation. > > I would like to add a subsystem, that will read the DTB and call > the appropriate drivers. > > I want to know how it is implemented in FreeBSD, I took a look at the > code, but I am still couldn't figure out, when does FreeBSD start to > parse the DTB, how does it fill up the device struct and few more. > > Can someone please explain how all this works with reference to code > or point me to some documentation? > > Thanks, > Niteesh > ___ > freebsd-current@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org" > ___ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
OFWBUS: How does autoconfiguration work?
I am interested in adding autoconfiguration to one of my projects. The current drivers use lazy initialization, for example, the UART drivers initialize the hardware only during their first invocation. I would like to add a subsystem, that will read the DTB and call the appropriate drivers. I want to know how it is implemented in FreeBSD, I took a look at the code, but I am still couldn't figure out, when does FreeBSD start to parse the DTB, how does it fill up the device struct and few more. Can someone please explain how all this works with reference to code or point me to some documentation? Thanks, Niteesh ___ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
