tree acb3bc4f43074d51d0bfbcc91efaf219a62f787f
parent 5670c2a52f60418f67dd589e20d30600804fcfde
author Krzysztof Kozlowski <k.kozlowski@samsung.com> 1415954937 +0100
committer Russell King <rmk+kernel@arm.linux.org.uk> 1416255816 +0000

ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12

This patch adds runtime PM support to pl330 DMA engine driver.

The runtime power management for pl330 DMA driver allows gating of AMBA
clock (PDMA) in FSYS clock domain, when the device is not processing any
requests. This is necessary to enter low power modes on Exynos SoCs
(e.g. LPA on Exynos4x12 or W-AFTR on Exynos3250).

Runtime PM resuming of the device may happen in atomic context (during
call device_issue_pending()) so pm_runtime_irq_safe() is used. This will
lead only to disabling/enabling of the clock but this is sufficient for
gating the clock and for reducing energy usage.

Driver uses runtime PM callbacks from amba/bus.c driver only.

Suggested-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>