Tejun Heo wrote:
There are several registers which describe how the controller is configured. These registers are sometimes implemented as r/w registers which are configured by firmware and get cleared on controller reset or after suspend/resume cycle. ahci saved and restored those values inside ahci_reset_controller() which is a bit messy and doesn't work over suspend/resume cycle. This patch implements ahci_save/restore_initial_config(). The save function is called during driver initialization and saves cap and port_map to hpriv. The restore function is called after the controller is reset to restore the initial values. Sometimes the initial firmware values are inconsistent and need to be fixed up. This is handled by ahci_save_initial_config(). For this, there are two versions of saved registers. One to write back to the hardware register, the other to use during driver operation. This is necessary to keep ahci's behavior unchanged (write back fixed up port_map while keeping cap as-is). This patch makes ahci save the register values once before the first controller reset, not after it's been reset. Also, the same stored values are used written back after each reset, so the register values are properly recovered after suspend/resume cycle. Signed-off-by: Tejun Heo <htejun@xxxxxxxxx> --- Jeff, this is the save/restore separation patch as suggested.
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