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2021-03-08clock: Add clock_ns_to_ticks() functionPeter Maydell
Add a clock_ns_to_ticks() function which does the opposite of clock_ticks_to_ns(): given a duration in nanoseconds, it returns the number of clock ticks that would happen in that time. This is useful for devices that have a free running counter register whose value can be calculated when it is read. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Luc Michel <luc@lmichel.fr> Reviewed-by: Hao Wu <wuhaotsh@google.com> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20210219144617.4782-4-peter.maydell@linaro.org
2021-03-08clock: Add ClockPreUpdate callback event typePeter Maydell
Add a new callback event type ClockPreUpdate, which is called on period changes before the period is updated. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Luc Michel <luc@lmichel.fr> Reviewed-by: Hao Wu <wuhaotsh@google.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20210219144617.4782-3-peter.maydell@linaro.org
2021-03-08clock: Add ClockEvent parameter to callbacksPeter Maydell
The Clock framework allows users to specify a callback which is called after the clock's period has been updated. Some users need to also have a callback which is called before the clock period is updated. As the first step in adding support for notifying Clock users on pre-update events, add an argument to the ClockCallback to specify what event is being notified, and add an argument to the various functions for registering a callback to specify which events are of interest to that callback. Note that the documentation update renders correct the previously incorrect claim in 'Adding a new clock' that callbacks "will be explained in a following section". Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Luc Michel <luc@lmichel.fr> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20210219144617.4782-2-peter.maydell@linaro.org
2021-01-29clock: Add new clock_has_source() functionPeter Maydell
Add a function for checking whether a clock has a source. This is useful for devices which have input clocks that must be wired up by the board as it allows them to fail in realize rather than ploughing on with a zero-period clock. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Luc Michel <luc@lmichel.fr> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20210128114145.20536-3-peter.maydell@linaro.org Message-id: 20210121190622.22000-3-peter.maydell@linaro.org
2021-01-04clock: Define and use new clock_display_freq()Peter Maydell
It's common to want to print a human-readable indication of a clock's frequency. Provide a utility function in the clock API to return a string which is a displayable representation of the frequency, and use it in qdev-monitor.c. Before: (qemu) info qtree [...] dev: xilinx,zynq_slcr, id "" clock-in "ps_clk" freq_hz=3.333333e+07 mmio 00000000f8000000/0000000000001000 After: dev: xilinx,zynq_slcr, id "" clock-in "ps_clk" freq_hz=33.3 MHz mmio 00000000f8000000/0000000000001000 Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Luc Michel <luc@lmichel.fr> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-Id: <20201215150929.30311-5-peter.maydell@linaro.org> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2021-01-04clock: Remove clock_get_ns()Peter Maydell
Remove the now-unused clock_get_ns() API and the CLOCK_PERIOD_TO_NS() macro that only it was using. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Luc Michel <luc@lmichel.fr> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-Id: <20201215150929.30311-4-peter.maydell@linaro.org> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2021-01-04clock: Introduce clock_ticks_to_ns()Peter Maydell
The clock_get_ns() API claims to return the period of a clock in nanoseconds. Unfortunately since it returns an integer and a clock's period is represented in units of 2^-32 nanoseconds, the result is often an approximation, and calculating a clock expiry deadline by multiplying clock_get_ns() by a number-of-ticks is unacceptably inaccurate. Introduce a new API clock_ticks_to_ns() which returns the number of nanoseconds it takes the clock to make a given number of ticks. This function can do the complete calculation internally and will thus give a more accurate result. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Luc Michel <luc@lmichel.fr> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-Id: <20201215150929.30311-2-peter.maydell@linaro.org> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2020-04-30docs/clocks: add device's clock documentationPeter Maydell
Add the documentation about the clock inputs and outputs in devices. This is based on the original work of Frederic Konrad. Signed-off-by: Damien Hedde <damien.hedde@greensocs.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Message-id: 20200406135251.157596-6-damien.hedde@greensocs.com [PMM: Editing pass for minor grammar, style and Sphinx formatting fixes] Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>