misc: mrvl-cn10k-dpi: add Octeon CN10K DPI administrative driver

Adds a misc driver for Marvell CN10K DPI(DMA Engine) device's physical
function which initializes DPI DMA hardware's global configuration and
enables hardware mailbox channels between physical function (PF) and
it's virtual functions (VF). VF device drivers (User space drivers) use
this hw mailbox to communicate any required device configuration on it's
respective VF device. Accordingly, this DPI PF driver provisions the
VF device resources.

At the hardware level, the DPI physical function (PF) acts as a management
interface to setup the VF device resources, VF devices are only provisioned
to handle or control the actual DMA Engine's data transfer capabilities.

Signed-off-by: Vamsi Attunuru <[email protected]>
Reviewed-by: Srujana Challa <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Documentation/misc-devices/index.rst

@@ -21,6 +21,7 @@ fit into other categories.
    isl29003
    lis3lv02d
    max6875
+   mrvl_cn10k_dpi
    oxsemi-tornado
    pci-endpoint-test
    spear-pcie-gadget

Documentation/misc-devices/mrvl_cn10k_dpi.rst

@@ -0,0 +1,52 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===============================================
+Marvell CN10K DMA packet interface (DPI) driver
+===============================================
+
+Overview
+========
+
+DPI is a DMA packet interface hardware block in Marvell's CN10K silicon.
+DPI hardware comprises a physical function (PF), its virtual functions,
+mailbox logic, and a set of DMA engines & DMA command queues.
+
+DPI PF function is an administrative function which services the mailbox
+requests from its VF functions and provisions DMA engine resources to
+it's VF functions.
+
+mrvl_cn10k_dpi.ko misc driver loads on DPI PF device and services the
+mailbox commands submitted by the VF devices and accordingly initializes
+the DMA engines and VF device's DMA command queues. Also, driver creates
+/dev/mrvl-cn10k-dpi node to set DMA engine and PEM (PCIe interface) port
+attributes like fifo length, molr, mps & mrrs.
+
+DPI PF driver is just an administrative driver to setup its VF device's
+queues and provisions the hardware resources, it cannot initiate any
+DMA operations. Only VF devices are provisioned with DMA capabilities.
+
+Driver location
+===============
+
+drivers/misc/mrvl_cn10k_dpi.c
+
+Driver IOCTLs
+=============
+
+:c:macro::`DPI_MPS_MRRS_CFG`
+ioctl that sets max payload size & max read request size parameters of
+a pem port to which DMA engines are wired.
+
+
+:c:macro::`DPI_ENGINE_CFG`
+ioctl that sets DMA engine's fifo sizes & max outstanding load request
+thresholds.
+
+User space code example
+=======================
+
+DPI VF devices are probed and accessed from user space applications using
+vfio-pci driver. Below is a sample dpi dma application to demonstrate on
+how applications use mailbox and ioctl services from DPI PF kernel driver.
+
+https://github.com/MarvellEmbeddedProcessors/dpi-sample-app

Documentation/userspace-api/ioctl/ioctl-number.rst

@@ -362,6 +362,7 @@ Code  Seq#    Include File                                           Comments
 0xB6  all    linux/fpga-dfl.h
 0xB7  all    uapi/linux/remoteproc_cdev.h                            <mailto:[email protected]>
 0xB7  all    uapi/linux/nsfs.h                                       <mailto:Andrei Vagin <[email protected]>>
+0xB8  01-02  uapi/misc/mrvl_cn10k_dpi.h                              Marvell CN10K DPI driver
 0xC0  00-0F  linux/usb/iowarrior.h
 0xCA  00-0F  uapi/misc/cxl.h
 0xCA  10-2F  uapi/misc/ocxl.h

MAINTAINERS

@@ -13477,6 +13477,11 @@ S:	Supported
 F:	Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.yaml
 F:	drivers/mmc/host/sdhci-xenon*
 
+MARVELL OCTEON CN10K DPI DRIVER
+M:	Vamsi Attunuru <[email protected]>
+S:	Supported
+F:	drivers/misc/mrvl_cn10k_dpi.c
+
 MATROX FRAMEBUFFER DRIVER
 L:	[email protected]
 S:	Orphan

drivers/misc/Kconfig

@@ -585,6 +585,20 @@ config NSM
 	  To compile this driver as a module, choose M here.
 	  The module will be called nsm.
 
+config MARVELL_CN10K_DPI
+	tristate "Octeon CN10K DPI driver"
+	depends on PCI
+	help
+	  Enables Octeon CN10K DMA packet interface (DPI) driver which
+	  intializes DPI hardware's physical function (PF) device's
+	  global configuration and its virtual function (VFs) resource
+	  configuration to enable DMA transfers. DPI PF device does not
+	  have any data movement functionality, it only serves VF's
+	  resource configuration requests.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called mrvl_cn10k_dpi.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"

drivers/misc/Makefile

@@ -69,4 +69,5 @@ obj-$(CONFIG_TMR_INJECT)	+= xilinx_tmr_inject.o
 obj-$(CONFIG_TPS6594_ESM)	+= tps6594-esm.o
 obj-$(CONFIG_TPS6594_PFSM)	+= tps6594-pfsm.o
 obj-$(CONFIG_NSM)		+= nsm.o
+obj-$(CONFIG_MARVELL_CN10K_DPI)	+= mrvl_cn10k_dpi.o
 obj-y				+= keba/

drivers/misc/Makefile.rej

@@ -0,0 +1,7 @@
+--- drivers/misc/Makefile
++++ drivers/misc/Makefile
+@@ -69,3 +69,4 @@ obj-$(CONFIG_TMR_INJECT)	+= xilinx_tmr_inject.o
+ obj-$(CONFIG_TPS6594_ESM)	+= tps6594-esm.o
+ obj-$(CONFIG_TPS6594_PFSM)	+= tps6594-pfsm.o
+ obj-$(CONFIG_NSM)		+= nsm.o
++obj-$(CONFIG_MARVELL_CN10K_DPI)	+= mrvl_cn10k_dpi.o