dmaengine: idxd: Init and probe for Intel data accelerators

The idxd driver introduces the Intel Data Stream Accelerator [1] that will
be available on future Intel Xeon CPUs. One of the kernel access
point for the driver is through the dmaengine subsystem. It will initially
provide the DMA copy service to the kernel.

Some of the main functionality introduced with this accelerator
are: shared virtual memory (SVM) support, and descriptor submission using
Intel CPU instructions movdir64b and enqcmds. There will be additional
accelerator devices that share the same driver with variations to
capabilities.

This commit introduces the probe and initialization component of the
driver.

[1]: https://software.intel.com/en-us/download/intel-data-streaming-accelerator-preliminary-architecture-specification

Signed-off-by: Dave Jiang <[email protected]>
Link: https://lore.kernel.org/r/157965023991.73301.6186843973135311580.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <[email protected]>

Author: davejiang

MAINTAINERS

@@ -8375,6 +8375,14 @@ Q:	https://patchwork.kernel.org/project/linux-dmaengine/list/
 S:	Supported
 F:	drivers/dma/ioat*
 
+INTEL IADX DRIVER
+M:	Dave Jiang <[email protected]>
+L:	[email protected]
+S:	Supported
+F:	drivers/dma/idxd/*
+F:	include/uapi/linux/idxd.h
+F:	include/linux/idxd.h
+
 INTEL IDLE DRIVER
 M:	Jacob Pan <[email protected]>
 M:	Len Brown <[email protected]>

drivers/dma/Kconfig

@@ -273,6 +273,19 @@ config INTEL_IDMA64
 	  Enable DMA support for Intel Low Power Subsystem such as found on
 	  Intel Skylake PCH.
 
+config INTEL_IDXD
+	tristate "Intel Data Accelerators support"
+	depends on PCI && X86_64
+	select DMA_ENGINE
+	select SBITMAP
+	help
+	  Enable support for the Intel(R) data accelerators present
+	  in Intel Xeon CPU.
+
+	  Say Y if you have such a platform.
+
+	  If unsure, say N.
+
 config INTEL_IOATDMA
 	tristate "Intel I/OAT DMA support"
 	depends on PCI && X86_64

drivers/dma/Makefile

@@ -41,6 +41,7 @@ obj-$(CONFIG_IMX_DMA) += imx-dma.o
 obj-$(CONFIG_IMX_SDMA) += imx-sdma.o
 obj-$(CONFIG_INTEL_IDMA64) += idma64.o
 obj-$(CONFIG_INTEL_IOATDMA) += ioat/
+obj-$(CONFIG_INTEL_IDXD) += idxd/
 obj-$(CONFIG_INTEL_IOP_ADMA) += iop-adma.o
 obj-$(CONFIG_INTEL_MIC_X100_DMA) += mic_x100_dma.o
 obj-$(CONFIG_K3_DMA) += k3dma.o

drivers/dma/idxd/Makefile

@@ -0,0 +1,2 @@
+obj-$(CONFIG_INTEL_IDXD) += idxd.o
+idxd-y := init.o irq.o device.o