On 28 September 2011 19:42, Blue Swirl <blauwir...@gmail.com> wrote: > We also assume that the reset states of devices and their outputs are > coherent i.e. the output of one device during reset would not change > the state of another device from its reset state.
This seems a very dubious assumption to make. Consider the realview board: the 'card present' line from the pl181 MMC card controller is wired up to (1) a GPIO input on the 'sysctl' system register module [which causes it to appear as a status bit in a register] and (2) via an inverter to an input on a pl061 GPIO module. On coming out of reset something has to be done to make the reset value of the output from the pl181 be reflected in the internal status of the sysctl and pl061 devices. (On real hardware this happens when the pl061/sysctl devices come out of reset and sample their input pins. If we wanted to model it that way we'd need internal state on all gpio lines and a two phase "enter reset"+"leave reset" or something.) -- PMM
