dmaengine: qcom: Add ADM driver

Add the DMA engine driver for the QCOM Application Data Mover (ADM) DMA
controller found in the MSM8x60 and IPQ/APQ8064 platforms.

The ADM supports both memory to memory transactions and memory
to/from peripheral device transactions.  The controller also provides
flow control capabilities for transactions to/from peripheral devices.

The initial release of this driver supports slave transfers to/from
peripherals and also incorporates CRCI (client rate control interface)
flow control.

The hardware only supports a 32 bit physical address, so specifying
!PHYS_ADDR_T_64BIT gives maximum COMPILE_TEST coverage without having to
spend effort on kludging things in the code that will never actually be
needed on real hardware.

Signed-off-by: Andy Gross <agross@codeaurora.org>
Signed-off-by: Thomas Pedersen <twp@codeaurora.org>
Signed-off-by: Jonathan McDowell <noodles@earth.li>
Link: https://lore.kernel.org/r/20201114140233.GM32650@earth.li
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/qcom/Kconfig

@@ -1,4 +1,15 @@
 # SPDX-License-Identifier: GPL-2.0-only
+config QCOM_ADM
+	tristate "Qualcomm ADM support"
+	depends on (ARCH_QCOM || COMPILE_TEST) && !PHYS_ADDR_T_64BIT
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Enable support for the Qualcomm Application Data Mover (ADM) DMA
+	  controller, as present on MSM8x60, APQ8064, and IPQ8064 devices.
+	  This controller provides DMA capabilities for both general purpose
+	  and on-chip peripheral devices.
+
 config QCOM_BAM_DMA
 	tristate "QCOM BAM DMA support"
 	depends on ARCH_QCOM || (COMPILE_TEST && OF && ARM)

drivers/dma/qcom/Makefile

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_QCOM_ADM) += qcom_adm.o
 obj-$(CONFIG_QCOM_BAM_DMA) += bam_dma.o
 obj-$(CONFIG_QCOM_HIDMA_MGMT) += hdma_mgmt.o
 hdma_mgmt-objs	 := hidma_mgmt.o hidma_mgmt_sys.o