On Thu, 7 Jun 2012, Tony Lindgren wrote: > It seems that most/many IP blocks need their custom reset hacks, and > it's not limited to just few instances? Only four out of the fifty-seven omap_hwmod_classes defined in mach-omap2/omap_hwmod_44xx_data.c after this series have custom reset functions used: $ fgrep 'struct omap_hwmod_class ' arch/arm/mach-omap2/omap_hwmod_44xx_data.c | wc -l 57 $ fgrep '.reset' arch/arm/mach-omap2/omap_hwmod_44xx_data.c | wc -l 4 That's 7% of the classes. In terms of the total number of IP block instances that use custom reset functions viewed against the total number of instances on the chip, the percentage is even smaller. > AFAIK there's no need to reset the IP blocks before the driver init, > it's really needed for PM. So it's not needed early on, and it's OK to > require running the driver init for driver modules that are not in use > to reset them properly. After all, the hardware is on the device, even > if it's not being used. I don't think I'm following you. It's not just PM; the problem is also with kexec or buggy bootloaders. If an IP block isn't reset when the kernel boots, and is doing DMA or anything else that could affect the reset of the system, it could easily cause unpredictable behavior or crashes in unrelated kernel code. It's also worth mentioning that many IP blocks, such as AESS, don't have Linux drivers. - Paul -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
