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Blobless Linux on Raspberry Pi

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Re: Blobless Linux on Raspberry Pi

#81

Post by christina_b »

makomk wrote: post #76
christina_b wrote: post #73

Earlier quoted context omitted.

All modern ARM chips support secure mode, it's a set of modes, in AArch64, we colloquially call them EL3 (Exception level 3, highest privilege level above EL2, the hypervisor level). Most ARM cores start in secure supervisor mode, which can transition to secure monitor mode at will (secure monitor being a special version of secure supervisor). Most bootloaders including Allwinner's will exit secure mode by setting th…

Well, of course they support secure mode/EL3, it's just not exactly secure on any Allwinner-based system I'm aware of because the ROM bootloader will happily load any chunk of code yo choose to supply into RAM from the boot device and jump to it whilst still in EL3, without any signature checks. Allwinner really don't seem to be keen on locking their chips down.

Hm, I may have been wrong, would be nice to have someone who owns one of these boards to verify that:

1). The first stage bootloader doesn't require signing.

2). The first stage bootloader starts in EL3 mode (ie. BootROM doesn't exit it like it did on some OMAP dev boards)

Re: Blobless Linux on Raspberry Pi

#82

Post by rektide »

faragon wrote: post #33
rektide wrote: post #2

Sadists. The Pi's choice of picking one of the most egregiously unsupported and anti-open source CPU cores was absurd. The people doing the absurdly hard work of taking up the slack that the Raspberry Pi Foundation created from this pick AND the RPI Foundations complete unconcern about the situation and open source at large is to me beyond belief. For a thing that purported to be an educational platform, this situati…

The "24 GFLOPS" in RP come from the GPU (Videocore IV, 32-bit precision) [1]. The PS3 does more than 230 GFLOPS, just with the Cell processor (1 dual threaded CPU and 7 vector units -CPUs with wide SIMD, working in 256KB local scratchpad RAM-) [2]. In addition to that, the PS3 GPU does 400 GFLOPS [3]. So the PS3 is "600 GFLOPS" (32-bit precision). [1] https://github.com/hermanhermitage/videocoreiv/wiki/VideoCor... [2…

Oh my goodness how right you are. I'm very sorry! I should have checked this far better. Again, super sorry.

I believe I was unintentionally citing that a single Cell SPE is 25.6 GFLOPS: https://en.wikipedia.org/wiki/Cell_(microprocessor)#Synergis...

Re: Blobless Linux on Raspberry Pi

#84

Post by owenversteeg »

Stupid question: does this now mean that you can boot a RPi to Linux with zero blobs involved?

Additional question: does anyone have a list of devices that you can boot without any blobs involved? E.x. if someone wants to go "full Stallman" what are the options to do that?

Re: Blobless Linux on Raspberry Pi

#85

Post by rektide »

joezydeco wrote: post #62
rektide wrote: post #2

Sadists. The Pi's choice of picking one of the most egregiously unsupported and anti-open source CPU cores was absurd. The people doing the absurdly hard work of taking up the slack that the Raspberry Pi Foundation created from this pick AND the RPI Foundations complete unconcern about the situation and open source at large is to me beyond belief. For a thing that purported to be an educational platform, this situati…

I know this is still heresy even though we're long past the "RPi is an educational tool for kids!" phase...but you have other choices .

I still use a lot of the Marvell Kirkwood units I had from 2009 or so. My first was a OpenRD board which was I think like $160, but there was a ton of low-end NAS & other gear. My favorite unit was the Iomega iConnect, a simple unit having a plush 512MB flash, 256MB ram, 4 USB ports, gbit ethernet, and an Atheros chipset, and could be had on ebay for $65. Havent had any running for a while, but for a good while these were all over the place.

iomega iconnect: https://wiki.openwrt.org/toh/iomega/iconnect

The Kirkwood was fair. 1.6GHz ARMv5TE-ish cores, custom architecture, but sipping data through a 16 bit DDR2 channel. I had hope that Marvell would progress and keep it up, but they seemed to get harder to find and harder to use and less supported and only show up in some random Android STB as the years went on.

But this is the basis I had during RPi's 2012 arrival. Still flush with hope, of decent upstreamed cores, & it seemed rather like an unfortunate step back. That said, I was buying for twice the price of RPi while only paying rather discounted ebay prices, albeit for consumer goods with wifi, flash, cases, & warranties.

I'm still not sure what I'd point people to today if I wanted to suggest an alternative. The good work done in making blobless rpi happen, in building good upstream drivers has been incredibly impressive. I do wish Freescale had better recognized the need for low cost boards. Now a days, Atmel's SAMA5D3-Xplorer board has really good upstream, great peripherals, Arduino headers, and has fantastic power consumption, but it's three times the RPi price.

Re: Blobless Linux on Raspberry Pi

#86

Post by rektide »

viraptor wrote: post #8
rektide wrote: post #2

Sadists. The Pi's choice of picking one of the most egregiously unsupported and anti-open source CPU cores was absurd. The people doing the absurdly hard work of taking up the slack that the Raspberry Pi Foundation created from this pick AND the RPI Foundations complete unconcern about the situation and open source at large is to me beyond belief. For a thing that purported to be an educational platform, this situati…

> Sadists. You meant masochists?

Uggghhh I meant masochists. That's a... very unfortunate mistake. As I said already in this thread (RE getting the GFLOPS way wrong), sorry!!!

I meant masochists. Thanks for questioning.

Re: Blobless Linux on Raspberry Pi

#87

Post by userbinator »

vvanders wrote: post #78
Itsdijital wrote: post #24

Earlier quoted context omitted.

The founder and CEO of RPi was a technical director and ASIC architect at Broadcom. Looking at it like that, its dead obvious why they went with broadcom.

Yup and Eben Upton did it to teach basics of computer programming and development since he was so frustrated with the state of things in the UK. I really hate the attitude of the root post that holds open hardware above everything else. RPi has done a ton to help education getting a new generation excited about computers.

teach basics of computer programming and development

There are already Arduinos and regular PCs (of which you will find far more documentation on... especially the latter) for that. Why make another closed proprietary system just for teaching? All it will do is make those educated (indoctrinated?) by it think this type of environment should be the norm and encouraged, when there are in fact plenty of better ones.

Even a C64 or a ZX Spectrum would be a better choice than an RPi for teaching.

Re: Blobless Linux on Raspberry Pi

#88

Post by userbinator »

technion wrote: post #55
paulmd wrote: post #46

Earlier quoted context omitted.

It's really doubtful that more than a tiny fraction of RPi sales have gone to kids. Be honest here, whatever the RPi Foundation's marketing, the overwhelming majority have gone to hobbyists. The RPi is uniquely unsuited to an educational environment anyway. The SD cards are unreliable, especially in combination with the RPi's poor power filtering and the cheapo phone adapters it's usually paired with. Anyone who has…

SD card failures I'd love someone knowledgeable to explain why this happens. According to general opinion on the RPi forums, it's because SD card manufacturers cheap out all the time. I'd have something like a dozen SD cards running things like cameras over the years, and probably a hundred booting ESXi servers. And I've never seen a failure. Across three RPis, I've bought about seven SD cards, and from everything RP…

In regards to cheap whiteboxes, no such options allow access to GPIO ports.

The parallel port on older PCs works reasonably well as GPIO; you can get expansion cards for those which don't have one (they seem to have gone up in price now but they used to be extremely cheap.) Since this is an actual external interface it will be more robust than the GPIOs directly connected to the SoC of the RPi, and if you use expansion cards you can just swap them out if they do get damaged.

Re: Blobless Linux on Raspberry Pi

#90

Post by agumonkey »

joezydeco wrote: post #67
agumonkey wrote: post #53

Earlier quoted context omitted.

What SoC of that class (perf/price) was on shelves when the rpi started ?

OMAP3, OMAP4, Sitara, iMX5, iMX6. The Broadcom part in the RPi was heavily subsidized. Don't be fooled by price here.

Yes but still, at that time these SoC alone were above the rpi board price point. If you wanted to sell something aronud 30 you had to do vendor tricks with odd parts.
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