2017-04-27 13:21 GMT+02:00 Luke Kenneth Casson Leighton <l...@lkcl.net>:
> ok so it would seem that the huge amount of work going into RISC-V > means that it's on track to becoming a steamroller that will squash > proprietary SoCs, so i'm quite happy to make sure that it's > not-so-subtly nudged in the right direction. > > i've started a page where i am keeping notes: > http://rhombus-tech.net/riscv/libre_riscv/ and the general goal is to > create a desirable mass-volume low-cost SoC, meaning that it will need > to at least do 1080p60 video decode and have 3D graphics capability. > oh... and be entirely libre. > > the plan is: > > * to create an absolute basic SoC, starting from lowRISC (64-bit), > ORGFX (3D graphics) and MIAOW (OpenCL engine), in at least 90nm as a > low-cost proof-of-concept where mistakes can be iterated through > * provide the end-result to software developers so that they can have > actual real silicon to work with > * begin a first crowd-funding phase to create a 28nm (or better) > multi-core SMP SoC > > for this first phase the interfaces that i've tracked down so far are > almost entirely from opencores.org, meaning that there really should > be absolutely no need to license any costly hard macros. that > *includes* a DDR3 controller (but does not include a DDR3 PHY, which > will need to be designed): > > * DDR3 controller (not including PHY) > * lowRISC contains "minion cores" so can be soft-programmed to do any GPIO > * boot and debug through ZipCPU's UART (use an existing EC's on-board > FLASH) > Perhaps put it sirectly to an USB bridge. UART's on debugging hardware is non existant. We all use FTDI dongles. Look like OpenCores has a module. https://opencores.org/project,usb2uart > * OpenCores VGA controller (actually it's an LCD RGB/TTL controller) > * OpenCores ULPI USB 2.0 controller > * OpenCores USB-OTG 1.1 PHY > > note that there are NO ANALOG INTERFACES in that. this is *really* > important to avoid, because mixed analog and digital is incredibly > hard to get right. also note that things like HDMI, SATA, and even > ethernet are quite deliberately NOT on the list. Ethernet RMII (which > is digital) could be implemented in software using a minion core. the > advantage of using the opencores VGA (actually LCD) controller is: i > already have the full source for a *complete* linux driver. > > I2C, SPI, SD/MMC, UART, EINT and GPIO - all of these can be > software-programmed as bit-banging in the minion cores. > > these interfaces, amazingly, are enough to do an SoC that, if put into > 40nm, would easily compete with some of TI's offerings, as well as the > Allwinner R8 (aka A13). > > i've also managed to get alliance and coriolis2 compiled on > debian/testing (took a while) so it *might* not be necessary even to > pay for the ASIC design tooling (the cost of which is insane). > coriolis2 includes a reasonable auto-router. i still have yet to go > through the tutorials to see how it works. for design rules: 90nm > design rules (stacks etc.) are actually publicly available, which > would potentially mean that a clock rate of at least 300mhz would be > achievable: interestingly 800mhz DDR3 RAM from 2012 used 90nm > geometry. 65 down to 40nm would be much more preferable but may be > hard to get. > > graphics: i'm going through the list of people who have done GPUs (or > parts of one). MIAOW, Nyuzi, ORGFX. the gplgpu isn't gpl. it's been > modified to "the text of the GPL license plus an additional clause > which is that if you want to use this for commercial purposes then... > you can't". which is *NOT* a GPL license, it's a proprietary > commercial license! > > MIAOW is just an OpenCL engine but a stonking good one that's > compatible with AMD's software. nyuzi is an experimental GPU where i > hope its developer believes in its potential. ORGFX i am currently > evaluating but it looks pretty damn good, and i think it is slightly > underestimated. i could really use some help evaluating it properly. > my feeling is that a combination of MIAOW to handle shading and ORGFX > for the rendering would be a really powerful combination. > > so. > > it's basically doable. comments and ideas welcome, please do edit the > page to keep track of notes http://rhombus-tech.net/riscv/libre_riscv/ > > --- > crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68 > > _______________________________________________ > arm-netbook mailing list arm-netbook@lists.phcomp.co.uk > http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook > Send large attachments to arm-netb...@files.phcomp.co.uk
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