Staging: most: add MOST driver's core module

This patch adds the core module of the MOST driver to the kernel's driver
staging area. This module is part of the MOST driver and handles the
configuration interface in sysfs, the buffer management and the data
routing.

MOST defines the protocol, hardware and software layers necessary to allow
for the efficient and low-cost transport of control, real-time and packet
data using a single medium (physical layer). Media currently in use are
fiber optics, unshielded twisted pair cables (UTP) and coax cables. MOST
also supports various speed grades up to 150 Mbps.
For more information on MOST, visit the MOST Cooperation website:
www.mostcooperation.com.

Cars continue to evolve into sophisticated consumer electronics platforms,
increasing the demand for reliable and simple solutions to support audio,
video and data communications. MOST can be used to connect multiple
consumer devices via optical or electrical physical layers directly to one
another or in a network configuration. As a synchronous network, MOST
provides excellent Quality of Service and seamless connectivity for
audio/video streaming. Therefore, the driver perfectly fits to the mission
of Automotive Grade Linux to create open source software solutions for
automotive applications.

The driver consists basically of three layers. The hardware layer, the
core layer and the application layer. The core layer consists of the core
module only. This module handles the communication flow through all three
layers, the configuration of the driver, the configuration interface
representation in sysfs, and the buffer management.
For each of the other two layers a selection of modules is provided. These
modules can arbitrarily be combined to meet the needs of the desired
system architecture. A module of the hardware layer is referred to as an
HDM (hardware dependent module). Each module of this layer handles exactly
one of the peripheral interfaces of a network interface controller (e.g.
USB, MediaLB, I2C). A module of the application layer is referred to as an
AIM (application interfacing module). The modules of this layer give access
to MOST via one the following ways: character devices, ALSA, Networking or
V4L2.

To physically access MOST, an Intelligent Network Interface Controller
(INIC) is needed. For more information on available controllers visit:
www.microchip.com

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/Kconfig

@@ -112,4 +112,6 @@ source "drivers/staging/fsl-mc/Kconfig"
 
 source "drivers/staging/wilc1000/Kconfig"
 
+source "drivers/staging/most/Kconfig"
+
 endif # STAGING

drivers/staging/Makefile

@@ -48,3 +48,4 @@ obj-$(CONFIG_COMMON_CLK_XLNX_CLKWZRD)	+= clocking-wizard/
 obj-$(CONFIG_FB_TFT)		+= fbtft/
 obj-$(CONFIG_FSL_MC_BUS)	+= fsl-mc/
 obj-$(CONFIG_WILC1000)		+= wilc1000/
+obj-$(CONFIG_MOST)		+= most/

drivers/staging/most/Kconfig

@@ -0,0 +1,16 @@
+menuconfig MOST
+        tristate "MOST driver"
+        select MOSTCORE
+        default n
+        ---help---
+          This option allows you to enable support for MOST Network transceivers.
+
+          If in doubt, say N here.
+
+
+
+if MOST
+
+source "drivers/staging/most/mostcore/Kconfig"
+
+endif

drivers/staging/most/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_MOSTCORE)	+= mostcore/

drivers/staging/most/TODO

@@ -0,0 +1,8 @@
+* Get through code review with Greg Kroah-Hartman
+
+Contact:
+To:
+Christian Gromm <christian.gromm@microchip.com>
+Cc:
+Michael Fabry <Michael.Fabry@microchip.com>
+Christian Gromm <chris@engineersdelight.de>

drivers/staging/most/mostcore/Kconfig

@@ -0,0 +1,13 @@
+#
+# MOSTCore configuration
+#
+
+config MOSTCORE
+	tristate "MOST Core"
+
+	---help---
+	  Say Y here if you want to enable MOST support.
+	  This device driver needs at least an additional AIM and HDM to work.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called mostcore.

drivers/staging/most/mostcore/Makefile

@@ -0,0 +1,3 @@
+obj-$(CONFIG_MOSTCORE) += mostcore.o
+
+mostcore-objs := core.o

drivers/staging/most/mostcore/mostcore.h

@@ -0,0 +1,316 @@
+/*
+ * mostcore.h - Interface between MostCore,
+ *   Hardware Dependent Module (HDM) and Application Interface Module (AIM).
+ *
+ * Copyright (C) 2013-2015, Microchip Technology Germany II GmbH & Co. KG
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * This file is licensed under GPLv2.
+ */
+
+/*
+ * Authors:
+ *   Andrey Shvetsov <andrey.shvetsov@k2l.de>
+ *   Christian Gromm <christian.gromm@microchip.com>
+ *   Sebastian Graf
+ */
+
+#ifndef __MOST_CORE_H__
+#define __MOST_CORE_H__
+
+#include <linux/types.h>
+
+struct kobject;
+struct module;
+
+/**
+ * Interface type
+ */
+enum most_interface_type {
+	ITYPE_LOOPBACK = 1,
+	ITYPE_I2C,
+	ITYPE_I2S,
+	ITYPE_TSI,
+	ITYPE_HBI,
+	ITYPE_MEDIALB_DIM,
+	ITYPE_MEDIALB_DIM2,
+	ITYPE_USB,
+	ITYPE_PCIE
+};
+
+/**
+ * Channel direction.
+ */
+enum most_channel_direction {
+	MOST_CH_RX = 1 << 0,
+	MOST_CH_TX = 1 << 1,
+};
+
+/**
+ * Channel data type.
+ */
+enum most_channel_data_type {
+	MOST_CH_CONTROL = 1 << 0,
+	MOST_CH_ASYNC = 1 << 1,
+	MOST_CH_ISOC_AVP = 1 << 2,
+	MOST_CH_SYNC = 1 << 5,
+};
+
+
+enum mbo_status_flags {
+	/* MBO was processed successfully (data was send or received )*/
+	MBO_SUCCESS = 0,
+	/* The MBO contains wrong or missing information.  */
+	MBO_E_INVAL,
+	/* MBO was completed as HDM Channel will be closed */
+	MBO_E_CLOSE,
+};
+
+/**
+ * struct most_channel_capability - Channel capability
+ * @direction: Supported channel directions.
+ * The value is bitwise OR-combination of the values from the
+ * enumeration most_channel_direction. Zero is allowed value and means
+ * "channel may not be used".
+ * @data_type: Supported channel data types.
+ * The value is bitwise OR-combination of the values from the
+ * enumeration most_channel_data_type. Zero is allowed value and means
+ * "channel may not be used".
+ * @num_buffer_packet: Maximum number of buffers supported by this channel
+ * for packet data types (Async,Control,QoS)
+ * @buffer_size_packet: Maximum buffer size supported by this channel
+ * for packet data types (Async,Control,QoS)
+ * @num_buffer_streaming: Maximum number of buffers supported by this channel
+ * for streaming data types (Sync,AV Packetized)
+ * @buffer_size_streaming: Maximum buffer size supported by this channel
+ * for streaming data types (Sync,AV Packetized)
+ * @name_suffix: Optional suffix providean by an HDM that is attached to the
+ * regular channel name.
+ *
+ * Describes the capabilities of a MostCore channel like supported Data Types
+ * and directions. This information is provided by an HDM for the MostCore.
+ *
+ * The Core creates read only sysfs attribute files in
+ * /sys/devices/virtual/most/mostcore/devices/mdev-#/mdev#-ch#/ with the
+ * following attributes:
+ *	-available_directions
+ *	-available_datatypes
+ *	-number_of_packet_buffers
+ *	-number_of_stream_buffers
+ *	-size_of_packet_buffer
+ *	-size_of_stream_buffer
+ * where content of each file is a string with all supported properties of this
+ * very channel attribute.
+ */
+struct most_channel_capability {
+	u16 direction;
+	u16 data_type;
+	u16 num_buffers_packet;
+	u16 buffer_size_packet;
+	u16 num_buffers_streaming;
+	u16 buffer_size_streaming;
+	char *name_suffix;
+};
+
+/**
+ * struct most_channel_config - stores channel configuration
+ * @direction: direction of the channel
+ * @data_type: data type travelling over this channel
+ * @num_buffers: number of buffers
+ * @buffer_size: size of a buffer for AIM.
+ * Buffer size may be cutted down by HDM in a configure callback
+ * to match to a given interface and channel type.
+ * @extra_len: additional buffer space for internal HDM purposes like padding.
+ * May be set by HDM in a configure callback if needed.
+ * @subbuffer_size: size of a subbuffer
+ * @packets_per_xact: number of MOST frames that are packet inside one USB
+ *		      packet. This is USB specific
+ *
+ * Describes the configuration for a MostCore channel. This information is
+ * provided from the MostCore to a HDM (like the Medusa PCIe Interface) as a
+ * parameter of the "configure" function call.
+ */
+struct most_channel_config {
+	enum most_channel_direction direction;
+	enum most_channel_data_type data_type;
+	u16 num_buffers;
+	u16 buffer_size;
+	u16 extra_len;
+	u16 subbuffer_size;
+	u16 packets_per_xact;
+};
+
+/*
+ * struct mbo - MOST Buffer Object.
+ * @context: context for core completion handler
+ * @priv: private data for HDM
+ *
+ *	public: documented fields that are used for the communications
+ *	between MostCore and HDMs
+ *
+ * @list: list head for use by the mbo's current owner
+ * @ifp: (in) associated interface instance
+ * @hdm_channel_id: (in) HDM channel instance
+ * @virt_address: (in) kernel virtual address of the buffer
+ * @bus_address: (in) bus address of the buffer
+ * @buffer_length: (in) buffer payload length
+ * @processed_length: (out) processed length
+ * @status: (out) transfer status
+ * @complete: (in) completion routine
+ *
+ * The MostCore allocates and initializes the MBO.
+ *
+ * The HDM receives MBO for transfer from MostCore with the call to enqueue().
+ * The HDM copies the data to- or from the buffer depending on configured
+ * channel direction, set "processed_length" and "status" and completes
+ * the transfer procedure by calling the completion routine.
+ *
+ * At the end the MostCore deallocates the MBO or recycles it for further
+ * transfers for the same or different HDM.
+ *
+ * Directions of usage:
+ * The core driver should never access any MBO fields (even if marked
+ * as "public") while the MBO is owned by an HDM. The ownership starts with
+ * the call of enqueue() and ends with the call of its complete() routine.
+ *
+ *					II.
+ * Every HDM attached to the core driver _must_ ensure that it returns any MBO
+ * it owns (due to a previous call to enqueue() by the core driver) before it
+ * de-registers an interface or gets unloaded from the kernel. If this direction
+ * is violated memory leaks will occur, since the core driver does _not_ track
+ * MBOs it is currently not in control of.
+ *
+ */
+struct mbo {
+	void *context;
+	void *priv;
+	struct list_head list;
+	struct most_interface *ifp;
+	u16 hdm_channel_id;
+	void *virt_address;
+	dma_addr_t bus_address;
+	u16 buffer_length;
+	u16 processed_length;
+	enum mbo_status_flags status;
+	void (*complete)(struct mbo *);
+};
+
+/**
+ * Interface instance description.
+ *
+ * Describes one instance of an interface like Medusa PCIe or Vantage USB.
+ * This structure is allocated and initialized in the HDM. MostCore may not
+ * modify this structure.
+ *
+ * @interface Interface type. \sa most_interface_type.
+ * @description PRELIMINARY.
+ *   Unique description of the device instance from point of view of the
+ *   interface in free text form (ASCII).
+ *   It may be a hexadecimal presentation of the memory address for the MediaLB
+ *   IP or USB device ID with USB properties for USB interface, etc.
+ * @num_channels Number of channels and size of the channel_vector.
+ * @channel_vector Properties of the channels.
+ *   Array index represents channel ID by the driver.
+ * @configure Callback to change data type for the channel of the
+ *   interface instance. May be zero if the instance of the interface is not
+ *   configurable. Parameter channel_config describes direction and data
+ *   type for the channel, configured by the higher level. The content of
+ * @enqueue Delivers MBO to the HDM for processing.
+ *   After HDM completes Rx- or Tx- operation the processed MBO shall
+ *   be returned back to the MostCore using completion routine.
+ *   The reason to get the MBO delivered from the MostCore after the channel
+ *   is poisoned is the re-opening of the channel by the application.
+ *   In this case the HDM shall hold MBOs and service the channel as usual.
+ *   The HDM must be able to hold at least one MBO for each channel.
+ *   The callback returns a negative value on error, otherwise 0.
+ * @poison_channel Informs HDM about closing the channel. The HDM shall
+ *   cancel all transfers and synchronously or asynchronously return
+ *   all enqueued for this channel MBOs using the completion routine.
+ *   The callback returns a negative value on error, otherwise 0.
+ * @request_netinfo: triggers retrieving of network info from the HDM by
+ *   means of "Message exchange over MDP/MEP"
+ * @priv Private field used by mostcore to store context information.
+ */
+struct most_interface {
+	struct module *mod;
+	enum most_interface_type interface;
+	const char *description;
+	int num_channels;
+	struct most_channel_capability *channel_vector;
+	int (*configure)(struct most_interface *iface, int channel_idx,
+			 struct most_channel_config *channel_config);
+	int (*enqueue)(struct most_interface *iface, int channel_idx,
+		       struct mbo *mbo);
+	int (*poison_channel)(struct most_interface *iface, int channel_idx);
+	void (*request_netinfo)(struct most_interface *iface, int channel_idx);
+	void *priv;
+};
+
+/**
+ * struct most_aim - identifies MOST device driver to mostcore
+ * @name: Driver name
+ * @probe_channel: function for core to notify driver about channel connection
+ * @disconnect_channel: notification that a certain channel isn't available anymore
+ * @rx_completion: completion handler for received packets
+ * @tx_completion: completion handler for transmitted packets
+ * @context: context pointer to be used by mostcore
+ */
+struct most_aim {
+	const char *name;
+	int (*probe_channel)(struct most_interface *iface, int channel_idx,
+			     struct most_channel_config *cfg,
+			     struct kobject *parent, char *name);
+	int (*disconnect_channel)(struct most_interface *iface,
+				  int channel_idx);
+	int (*rx_completion)(struct mbo *mbo);
+	int (*tx_completion)(struct most_interface *iface, int channel_idx);
+	void *context;
+};
+
+/**
+ * most_register_interface - Registers instance of the interface.
+ * @iface: Pointer to the interface instance description.
+ *
+ * Returns a pointer to the kobject of the generated instance.
+ *
+ * Note: HDM has to ensure that any reference held on the kobj is
+ * released before deregistering the interface.
+ */
+struct kobject *most_register_interface(struct most_interface *iface);
+
+/**
+ * Deregisters instance of the interface.
+ * @intf_instance Pointer to the interface instance description.
+ */
+void most_deregister_interface(struct most_interface *iface);
+int most_submit_mbo(struct mbo *mbo);
+
+/**
+ * most_stop_enqueue - prevents core from enqueing MBOs
+ * @iface: pointer to interface
+ * @channel_idx: channel index
+ */
+void most_stop_enqueue(struct most_interface *iface, int channel_idx);
+
+/**
+ * most_resume_enqueue - allow core to enqueue MBOs again
+ * @iface: pointer to interface
+ * @channel_idx: channel index
+ *
+ * This clears the enqueue halt flag and enqueues all MBOs currently
+ * in wait fifo.
+ */
+void most_resume_enqueue(struct most_interface *iface, int channel_idx);
+int most_register_aim(struct most_aim *aim);
+int most_deregister_aim(struct most_aim *aim);
+struct mbo *most_get_mbo(struct most_interface *iface, int channel_idx);
+void most_put_mbo(struct mbo *mbo);
+int most_start_channel(struct most_interface *iface, int channel_idx);
+int most_stop_channel(struct most_interface *iface, int channel_idx);
+
+
+#endif /* MOST_CORE_H_ */