Imagination technologies has created a GPU product line specifically for automotive use, building functional safety throughout the design to minimise the need for system-level safety intervention when meeting ISO 26262 requirements, according to the company.

The automotive market is important to Imagination, which claims that over 200 million vehicles already have its GPUs in their digital cockpit displays and infotainment systems. “OEMs, Tier 1s and semiconductor vendors can integrate the [new] IP with the confidence and knowledge that ISO 26262 is achieved,” it claimed.

Dubbed ‘XS’ GPUs, where the ‘S’ represents safety-enhanced products, the new intellectual property is aimed at two kinds of processing:

Displaying safety critical information on electronic dashboards – an ASIL-B human-in-the-loop task

Processing algorithms in machine-controlled automated driving

To go along with it, the company has released a safety-critical software driver – ‘OpenGL Safety-Critical 2.0′.

“Safety has touched every block in the GPU, it can detect both transient or permanent faults,” Imagination director of automotive business Jamie Broome told Electronics Weekly. “You an genuinely rely on it to render or compute.”

“Going beyond lock-step mechanisms,” according to Imagination, “XS includes hardware mechanisms that carry out safety-critical workloads across compute and graphics while maximising performance.”

To protect displayed data on electronic dashboard screens, the company has implemented what it has branded ’tile region protection’.

Imagination-electronic-dashbardElectronic dashboard as the driver sees it

With this protection, critical objects to be displayed – for example, vehicle speed and warning ‘lights’ – are differentiated from non-critical data such as odometer or background graphics by tags set by the application – this is all the application has to do.

Imagination-tile-regional-protectionElectronic dashboard as the XS GPU sees it

Imagination’s rendering technology is tile-based (see tile boarders added to diagram left).

Whenever a critical object is to be displayed, the GPU sees the tag and automatically renders each of the tiles that will display the critical object twice, and then ensures both renders match before displaying the tile (highlighted in grey – speed and selected gear in this case).

According to Broome, other GPUs have to render the whole display twice each time critical information is included, even it it only occupies 5% of the screen, and they also require an associated CPU to manage the double rendering and checking.

In hardware, should the display be reconfigured, an XS GPU will automatically re-calculate the location to which the critical information has moved, and double-render the tiles at the new location.

GPUs from 1pixel/clock to 64pixels/clock are planned in the XS series, and 128pixel/clock if needed, said Broome.

For algorithm processing, Imagination has optimised its IP for driver-assistance algorithms, with out yet revealing what these optimisations are, and included the reliability-enhancing HyperLane technology that it announced last year for its IMG A-Series GPUs.

HyperLane is a form of hardware virtualisation that includes something like a hypervisor programme in hardware – different virtual machines can be swapped in and out of the GPU hardware without external intervention, and hardware states for each virtual machine are stored locally to speed the swap. “It is completely overhead free,” said Broome.

Virtualisation of all forms is there to prevent one application from being hacked through another application, or a crashed application from taking others with it. In theory, and according to Broome in practice with HyperLanes, no programme separated from another by a hypervisor can have any knowledge of, or interaction with, the other programmes inter-leaved onto the same hardware. “You can crash a thread and not take down the others,” he said.

For automotive use, as well as the additional functional safety hardware mentioned before, XS has an alternative HyperLane mode for the notoriously conservative automotive industry where, just to make extra sure there is no interaction, pipelines can be flushed and a single virtual machine given all of the GPUs resources while it runs.

Algorithm compute power in XS GPUs will span 16Gflop to 1Tflop.

Imagination recently passed an audit of its functional safety management system by Horbia MIRA and has received a statement of ISO 26262 process conformance.