}
-\frame{\frametitle{Does what we want already exist?}
+\frame{\frametitle{Does what we want already exist? Surely this is nonsense!}
\begin{center}
\includegraphics[height=2.4in]{nolibresocs.jpg}\\
{\bf Analysis of SoCs over the past 7+ years (answer: no)}
}
-\frame{\frametitle{What's the problem?}
+\frame{\frametitle{Breakdown of non-existence of fully-Libre SoCs}
\begin{itemize}
\item {\bf iMX6}: Libre bootable, Vivante 3D GPU (libre etnaviv)
and helping others fulfil their needs and goals)
\end{itemize}
{\it Detachment from the goal also helps. If someone else makes this
- product then GREAT! I can go do something else}
+ product then GREAT! I can go do something else}\\
+ \vspace{4pt}
+ {\bf However please do not automatically assume Ethical and Libre is
+ non-commercial. It's not nice, and it's not helping }
}
}
+\frame{\frametitle{Challenging Stuff [1] - Memory Interfaces}
+
+ \begin{itemize}
+ \item DDR3/4 PHYs are analog and very high speed.
+ Impedance training. Extreme timing tolerances on parallel buses.\\
+ No surprise they cost USD \$1m and above.
+ \item Symbiotic EDA will do (Libre) PHY layout for USD \$300k,
+ time to completion for chosen geometry: 8-12 months.
+ \end{itemize}
+ {\it Silicon-proven but still risky. What are the alternatives?}
+ \vspace{4pt}
+ \begin{itemize}
+ \item 133mhz 32-bit SDRAM (um...) maybe even FlexBus?
+ \item HyperRAM (aka JEDEC xSPI) 8-bit SPI 166mhz or DDR-300.\\
+ 300mbyte/sec for only 13 wires, not bad! (We'll take several)\\
+ http://libre-riscv.org/shakti/m\_class/HyperRAM/
+ \item HMC: insanely fast, very low power. OpenHMC (LGPL)
+ https://opencores.org/project/openhmc
+ \end{itemize}
+}
+
+
+\frame{\frametitle{Challenging Stuff [2] - Video Decode Engine}
+
+ \begin{itemize}
+ \item Richard Herveille's Video Core Blocks\\
+ https://opencores.org/project/video\_systems
+ \item Symbiotic EDA MP4 decoder in FPGA
+ \item H.264 seems to have been done...\\
+ https://github.com/adsc-hls/synthesizable\_h264
+ \item Really needs SIMD (or better, not-SIMD)\\
+ {http://libre-riscv.org/simple\_v\_extension/}
+ \item Definitely needs xBitManip (parallelised by Simple-V)\\
+ https://github.com/cliffordwolf/xbitmanip
+ \end{itemize}
+ {\it SIMD is insane. $O(N^6)$ opcode proliferation. See\\
+ https://www.sigarch.org/simd-instructions-considered-harmful/ \\
+ (1): P-Ext designed for Audio. (2): Investigate RI5CY's SIMD
+ }
+}
+
+
+\frame{\frametitle{Challenging Stuff [3] - Libre 3D GPU. Sigh.}
+
+ \begin{itemize}
+ \item Actual requirements quite modest: 30MP/s 100MT/s 5GFLOPS
+ but power/area is crucial ($2mm^2$ @ 40nm)
+ \item Nyuzi, MIAOW, GPLGPU (Number Nine), OGP.
+ \item Nyuzi based on Larrabee. Jeff Bush really helpful.
+ \item MIAOW is an OpenCL engine. GPLGPU is fixed-function
+ \item Nyuzi lessons: Software-only rendering not enough.
+ Getting through L1 cache takes most power. Fixed functions
+ such as parallel FP-Quad to ARGB Pixel, and Z-Buffer
+ needed.
+ \item Fallback is GC800 (\$250k) {\it contact me if you can do better!}
+ \end{itemize}
+ {\it Jacob Bachmeyer's Cache-control proposal turns L1 Cache into
+ scratchpad RAM. RVV is just too heavy (sorry!), Simple-V much
+ more light-weight and flexible.
+ }
+}
+
+
\frame{\frametitle{TODO}
\begin{itemize}