Hi, I've been trying to figure out the best way to bind together tegradrm and nvhost. I assume that nvhost and tegradrm will live as separate drivers, with tegradrm taking care of display controller, and nvhost taking care of host1x and other client devices. I've identified a bumps that we need to agree on. I've included here the problem and my proposal: 1) Device & driver registration tegradrm registers as platform_driver, and exports ioctl's. Here we already have to agree on which device the platform_driver maps to. Currently it maps to host1x, but we'll need to move control of host1x to nvhost driver. We'll need to pass drm_platform_init() some platform_device - I propose that we create a virtual device for this. 2) Device tree parsing At bootup, we need to parse only host1x node and create a device for that. host1x probe will need to dig into host1x to create the children. This is something that we'll need to implement first in the internal kernel. tegra-dc would get probed only after this sequence. If this is ok, I'll take care of this part, and adjustments to tegradrm when this becomes topical. We include in device tree the register addresses. Some information that would be needed is still clocks, clock gating behavior, power domain ids, mapping of client devices to channels, and mapping of sync points per channnel 3) The handling of ioctl's from user space The ioctl's represent the needed synchronization and channel functionality. I'll write the necessary glue. There would be two categories of ioctl's: 3a) Simple operations such as synchronization: Wait, signal, read, etc. are exported from nvhost as public APIs, and tegradrm simply calls them. No big hurdle there. I already have concept code to do this. 3b) Channel operations: tegradrm needs to have a concept of logical channel. Channel open creates a logical channel (/context) by calling nvhost. nvhost needs to know which hw is going to be used by the channel to be able to control power, and to map to physical channel, so that comes as a parameter in ioctl. Each channel operation needs to pass the channel id, and tegradrm passes the calls to nvhost. Most important operation is submit, which sends a command buffer to nvhost's queue. 4) Buffer management We already know that this is a missing part. Hopefully we can get this filled soon. Terje -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
