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Add a system controller for the m68k-virt machine. This controller allows the kernel to power off or reset the machine. Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-Id: <20210312214145.2936082-5-laurent@vivier.eu>
27 lines
957 B
Plaintext
27 lines
957 B
Plaintext
Virtual System Controller
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=========================
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This device is a simple interface defined for the pure virtual machine with no
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hardware reference implementation to allow the guest kernel to send command
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to the host hypervisor.
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The specification can evolve, the current state is defined as below.
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This is a MMIO mapped device using 256 bytes.
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Two 32bit registers are defined:
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1- the features register (read-only, address 0x00)
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This register allows the device to report features supported by the
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controller.
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The only feature supported for the moment is power control (0x01).
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2- the command register (write-only, address 0x04)
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This register allows the kernel to send the commands to the hypervisor.
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The implemented commands are part of the power control feature and
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are reset (1), halt (2) and panic (3).
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A basic command, no-op (0), is always present and can be used to test the
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register access. This command has no effect.
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