[PATCH v8 00/13] Introduce framework for SLIMbus device driver

[PATCH v8 00/13] Introduce framework for SLIMbus device driver

[srinivas.kandagatla]

From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

Thanks for everyone who reviewed v7 patchset, here is v8 with
review comments addressed.

SLIMbus (Serial Low Power Interchip Media Bus) is a specification
developed by MIPI (Mobile Industry Processor Interface) alliance.
SLIMbus is a 2-wire implementation, which is used to communicate with
peripheral components like audio-codec.
SLIMbus uses Time-Division-Multiplexing to accommodate multiple data
channels, and control channel. Control channel has messages to do
device-enumeration, messages to send/receive control-data to/from
SLIMbus devices, messages for port/channel management, and messages to
do bandwidth allocation.
Framework is introduced to support  multiple instances of the bus
(1 controller per bus), and multiple slave devices per controller.
SPI and I2C frameworks, and comments from last time when I submitted
the patches were referred-to while working on this framework.

These patchsets introduce device-management, OF helpers, and messaging
APIs, controller driver for Qualcomm's SLIMbus controller, and
clock-pause feature for entering/exiting low-power mode for SLIMbus.
Framework patches to do channel, port and bandwidth
management are work-in-progress and will be sent out once these
initial patches are accepted.

These patchsets were tested on Qualcomm Snapdragon processor board
using the controller driver, and a test slave device.

v7: https://lwn.net/Articles/739150/

Changes from v7 to v8:
* Fixed few warnings from kerneldoc
* Few cosmetic fixes suggested by Vinod
* made SLIMbus string usage more consistent with spec
* made probe mandatory for slim device
* replaced explicit info and value element apis with
  more generic api
* made driver_data aligned 
* cleaned up qcom controller driver as suggested by
  Charles and Jonathan

Sagar Dharia (9):
  Documentation: Add SLIMbus summary
  dt-bindings: Add SLIMbus bindings
  slimbus: Add SLIMbus bus type
  slimbus: core: Add slim controllers support
  slimbus: Add messaging APIs to slimbus framework
  slimbus: Add support for 'clock-pause' feature
  dt-bindings: Add qcom slimbus controller bindings
  slimbus: qcom: Add Qualcomm Slimbus controller driver
  slimbus: qcom: Add runtime-pm support using clock-pause

Srinivas Kandagatla (4):
  slimbus: core: add support to device tree helper
  regmap: add SLIMbus support
  slimbus: core: add common defines required for controllers
  MAINTAINERS: Add SLIMbus maintainer

 Documentation/devicetree/bindings/slimbus/bus.txt  |  50 ++
 .../devicetree/bindings/slimbus/slim-qcom-ctrl.txt |  39 ++
 Documentation/driver-api/slimbus/index.rst         |  15 +
 Documentation/driver-api/slimbus/summary.rst       | 108 +++
 MAINTAINERS                                        |   8 +
 drivers/Kconfig                                    |   2 +
 drivers/Makefile                                   |   1 +
 drivers/base/regmap/Kconfig                        |   4 +
 drivers/base/regmap/Makefile                       |   1 +
 drivers/base/regmap/regmap-slimbus.c               |  89 +++
 drivers/slimbus/Kconfig                            |  22 +
 drivers/slimbus/Makefile                           |   9 +
 drivers/slimbus/core.c                             | 487 +++++++++++++
 drivers/slimbus/messaging.c                        | 336 +++++++++
 drivers/slimbus/qcom-ctrl.c                        | 756 +++++++++++++++++++++
 drivers/slimbus/sched.c                            | 128 ++++
 drivers/slimbus/slimbus.h                          | 268 ++++++++
 include/linux/mod_devicetable.h                    |  13 +
 include/linux/regmap.h                             |  18 +
 include/linux/slimbus.h                            | 171 +++++
 20 files changed, 2525 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/slimbus/bus.txt
 create mode 100644 Documentation/devicetree/bindings/slimbus/slim-qcom-ctrl.txt
 create mode 100644 Documentation/driver-api/slimbus/index.rst
 create mode 100644 Documentation/driver-api/slimbus/summary.rst
 create mode 100644 drivers/base/regmap/regmap-slimbus.c
 create mode 100644 drivers/slimbus/Kconfig
 create mode 100644 drivers/slimbus/Makefile
 create mode 100644 drivers/slimbus/core.c
 create mode 100644 drivers/slimbus/messaging.c
 create mode 100644 drivers/slimbus/qcom-ctrl.c
 create mode 100644 drivers/slimbus/sched.c
 create mode 100644 drivers/slimbus/slimbus.h
 create mode 100644 include/linux/slimbus.h

-- 
2.15.0

[PATCH v8 01/13] Documentation: Add SLIMbus summary

[srinivas.kandagatla]

From: Sagar Dharia <sdharia@codeaurora.org>

SLIMbus (Serial Low Power Interchip Media Bus) is a specification
developed by MIPI (Mobile Industry Processor Interface) alliance.
SLIMbus is a 2-wire implementation, which is used to communicate with
peripheral components like audio-codec.

The summary of SLIMbus and API is documented in the 'summary' file.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 Documentation/driver-api/slimbus/index.rst   |  15 ++++
 Documentation/driver-api/slimbus/summary.rst | 108 +++++++++++++++++++++++++++
 2 files changed, 123 insertions(+)
 create mode 100644 Documentation/driver-api/slimbus/index.rst
 create mode 100644 Documentation/driver-api/slimbus/summary.rst

diff --git a/Documentation/driver-api/slimbus/index.rst b/Documentation/driver-api/slimbus/index.rst
new file mode 100644
index 000000000000..586f979659e6
--- /dev/null
+++ b/Documentation/driver-api/slimbus/index.rst
@@ -0,0 +1,15 @@
+=====================
+SLIMbus Documentation
+=====================
+
+.. toctree::
+   :maxdepth: 1
+
+   summary
+
+.. only::  subproject
+
+   Indices
+   =======
+
+   * :ref:`genindex`
diff --git a/Documentation/driver-api/slimbus/summary.rst b/Documentation/driver-api/slimbus/summary.rst
new file mode 100644
index 000000000000..ba165611725a
--- /dev/null
+++ b/Documentation/driver-api/slimbus/summary.rst
@@ -0,0 +1,108 @@
+============================
+Linux kernel SLIMbus support
+============================
+
+Overview
+========
+
+What is SLIMbus?
+----------------
+SLIMbus (Serial Low Power Interchip Media Bus) is a specification developed by
+MIPI (Mobile Industry Processor Interface) alliance. The bus uses master/slave
+configuration, and is a 2-wire multi-drop implementation (clock, and data).
+
+Currently, SLIMbus is used to interface between application processors of SoCs
+(System-on-Chip) and peripheral components (typically codec).SLIMbus uses
+Time-Division-Multiplexing to accommodate multiple data channels, and
+a control channel.
+
+The control channel is used for various control functions such as bus
+management, configuration and status updates.These messages can be unicast (e.g.
+reading/writing device specific values), or multicast (e.g. data channel
+reconfiguration sequence is a broadcast message announced to all devices)
+
+A data channel is used for data-transfer between 2 SLIMbus devices. Data
+channel uses dedicated ports on the device.
+
+Hardware description:
+---------------------
+SLIMbus specification has different types of device classifications based on
+their capabilities.
+A manager device is responsible for enumeration, configuration, and dynamic
+channel allocation. Every bus has 1 active manager.
+
+A generic device is a device providing application functionality (e.g. codec).
+
+Framer device is responsible for clocking the bus, and transmitting frame-sync
+and framing information on the bus.
+
+Each SLIMbus component has an interface device for monitoring physical layer.
+
+Typically each SoC contains SLIMbus component having 1 manager, 1 framer device,
+1 generic device (for data channel support), and 1 interface device.
+External peripheral SLIMbus component usually has 1 generic device (for
+functionality/data channel support), and an associated interface device.
+The generic device's registers are mapped as 'value elements' so that they can
+be written/read using SLIMbus control channel exchanging control/status type of
+information.
+In case there are multiple framer devices on the same bus, manager device is
+responsible to select the active-framer for clocking the bus.
+
+Per specification, SLIMbus uses "clock gears" to do power management based on
+current frequency and bandwidth requirements. There are 10 clock gears and each
+gear changes the SLIMbus frequency to be twice its previous gear.
+
+Each device has a 6-byte enumeration-address and the manager assigns every
+device with a 1-byte logical address after the devices report presence on the
+bus.
+
+Software description:
+---------------------
+There are 2 types of SLIMbus drivers:
+
+slim_controller represents a 'controller' for SLIMbus. This driver should
+implement duties needed by the SoC (manager device, associated
+interface device for monitoring the layers and reporting errors, default
+framer device).
+
+slim_device represents the 'generic device/component' for SLIMbus, and a
+slim_driver should implement driver for that slim_device.
+
+Device notifications to the driver:
+-----------------------------------
+Since SLIMbus devices have mechanisms for reporting their presence, the
+framework allows drivers to bind when corresponding devices report their
+presence on the bus.
+However, it is possible that the driver needs to be probed
+first so that it can enable corresponding SLIMbus device (e.g. power it up and/or
+take it out of reset). To support that behavior, the framework allows drivers
+to probe first as well  (e.g. using standard DeviceTree compatbility field).
+This creates the necessity for the driver to know when the device is functional
+(i.e. reported present). device_up callback is used for that reason when the
+device reports present and is assigned a logical address by the controller.
+
+Similarly, SLIMbus devices 'report absent' when they go down. A 'device_down'
+callback notifies the driver when the device reports absent and its logical
+address assignment is invalidated by the controller.
+
+Another notification "boot_device" is used to notify the slim_driver when
+controller resets the bus. This notification allows the driver to take necessary
+steps to boot the device so that it's functional after the bus has been reset.
+
+Clock-pause:
+------------
+SLIMbus mandates that a reconfiguration sequence (known as clock-pause) be
+broadcast to all active devices on the bus before the bus can enter low-power
+mode. Controller uses this sequence when it decides to enter low-power mode so
+that corresponding clocks and/or power-rails can be turned off to save power.
+Clock-pause is exited by waking up framer device (if controller driver initiates
+exiting low power mode), or by toggling the data line (if a slave device wants
+to initiate it).
+
+Messaging APIs:
+---------------
+The framework supports APIs to exchange control-information with a SLIMbus
+device. APIs can be synchronous or asynchronous.
+From controller's perspective, multiple buffers can be queued to/from
+hardware for sending/receiving data using slim_ctrl_buf circular buffer.
+The header file <linux/slimbus.h> has more documentation about messaging APIs.
-- 
2.15.0

[PATCH v8 02/13] dt-bindings: Add SLIMbus bindings

[srinivas.kandagatla]

From: Sagar Dharia <sdharia@codeaurora.org>

SLIMbus (Serial Low Power Interchip Media Bus) is a specification
developed by MIPI (Mobile Industry Processor Interface) alliance.
SLIMbus is a 2-wire implementation, which is used to communicate with
peripheral components like audio-codec.

This patch adds device tree bindings for the slimbus.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/slimbus/bus.txt | 50 +++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/slimbus/bus.txt

diff --git a/Documentation/devicetree/bindings/slimbus/bus.txt b/Documentation/devicetree/bindings/slimbus/bus.txt
new file mode 100644
index 000000000000..52fa6426388c
--- /dev/null
+++ b/Documentation/devicetree/bindings/slimbus/bus.txt
@@ -0,0 +1,50 @@
+SLIM(Serial Low Power Interchip Media Bus) bus
+
+SLIMbus is a 2-wire bus, and is used to communicate with peripheral
+components like audio-codec.
+
+Required property for SLIMbus controller node:
+- compatible	- name of SLIMbus controller
+
+Child nodes:
+Every SLIMbus controller node can contain zero or more child nodes
+representing slave devices on the bus. Every SLIMbus slave device is
+uniquely determined by the enumeration address containing 4 fields:
+Manufacturer ID, Product code, Device index, and Instance value for
+the device.
+If child node is not present and it is instantiated after device
+discovery (slave device reporting itself present).
+
+In some cases it may be necessary to describe non-probeable device
+details such as non-standard ways of powering up a device. In
+such cases, child nodes for those devices will be present as
+slaves of the SLIMbus controller, as detailed below.
+
+Required property for SLIMbus child node if it is present:
+- reg		- Should be ('Device index', 'Instance ID') from SLIMbus
+		  Enumeration  Address.
+		  Device Index Uniquely identifies multiple Devices within
+		  a single Component.
+		  Instance ID Is for the cases where multiple Devices of the
+		  same type or Class are attached to the bus.
+
+- compatible	-"slimMID,PID". The textual representation of Manufacturer ID,
+	 	  Product Code, shall be in lower case hexadecimal with leading
+		  zeroes suppressed
+
+SLIMbus example for Qualcomm's slimbus manager component:
+
+	slim@28080000 {
+		compatible = "qcom,apq8064-slim", "qcom,slim";
+		reg = <0x28080000 0x2000>,
+		interrupts = <0 33 0>;
+		clocks = <&lcc SLIMBUS_SRC>, <&lcc AUDIO_SLIMBUS_CLK>;
+		clock-names = "iface", "core";
+		#address-cells = <2>;
+		#size-cell = <0>;
+
+		codec: wcd9310@1,0{
+			compatible = "slim217,60";
+			reg = <1 0>;
+		};
+	};
-- 
2.15.0

[PATCH v8 03/13] slimbus: Add SLIMbus bus type

[srinivas.kandagatla]

From: Sagar Dharia <sdharia@codeaurora.org>

SLIMbus (Serial Low Power Interchip Media Bus) is a specification
developed by MIPI (Mobile Industry Processor Interface) alliance.
SLIMbus is a 2-wire implementation, which is used to communicate with
peripheral components like audio-codec.
SLIMbus uses Time-Division-Multiplexing to accommodate multiple data
channels, and control channel. Control channel has messages to do
device-enumeration, messages to send/receive control-data to/from
SLIMbus devices, messages for port/channel management, and messages to
do bandwidth allocation.
The framework supports multiple instances of the bus (1 controller per
bus), and multiple slave devices per controller.

This patch adds support to basic silmbus core which includes support to
SLIMbus type, slimbus device registeration and some basic data structures.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/Kconfig                 |   2 +
 drivers/Makefile                |   1 +
 drivers/slimbus/Kconfig         |  16 ++++++
 drivers/slimbus/Makefile        |   5 ++
 drivers/slimbus/core.c          | 115 +++++++++++++++++++++++++++++++++++++
 include/linux/mod_devicetable.h |  13 +++++
 include/linux/slimbus.h         | 123 ++++++++++++++++++++++++++++++++++++++++
 7 files changed, 275 insertions(+)
 create mode 100644 drivers/slimbus/Kconfig
 create mode 100644 drivers/slimbus/Makefile
 create mode 100644 drivers/slimbus/core.c
 create mode 100644 include/linux/slimbus.h

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 152744c5ef0f..c8e1d1c3f426 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -211,4 +211,6 @@ source "drivers/mux/Kconfig"
 
 source "drivers/opp/Kconfig"
 
+source "drivers/slimbus/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 1d034b680431..d233a95b3b24 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -87,6 +87,7 @@ obj-$(CONFIG_MTD)		+= mtd/
 obj-$(CONFIG_SPI)		+= spi/
 obj-$(CONFIG_SPMI)		+= spmi/
 obj-$(CONFIG_HSI)		+= hsi/
+obj-$(CONFIG_SLIMBUS)		+= slimbus/
 obj-y				+= net/
 obj-$(CONFIG_ATM)		+= atm/
 obj-$(CONFIG_FUSION)		+= message/
diff --git a/drivers/slimbus/Kconfig b/drivers/slimbus/Kconfig
new file mode 100644
index 000000000000..ecf94ef66f10
--- /dev/null
+++ b/drivers/slimbus/Kconfig
@@ -0,0 +1,16 @@
+#
+# SLIMbus driver configuration
+#
+menuconfig SLIMBUS
+	tristate "SLIMbus support"
+	help
+	  SLIMbus is standard interface between System-on-Chip and audio codec,
+	  and other peripheral components in typical embedded systems.
+
+	  If unsure, choose N.
+
+if SLIMBUS
+
+# SLIMbus controllers
+
+endif
diff --git a/drivers/slimbus/Makefile b/drivers/slimbus/Makefile
new file mode 100644
index 000000000000..49ac5dce3fef
--- /dev/null
+++ b/drivers/slimbus/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for kernel SLIMbus framework.
+#
+obj-$(CONFIG_SLIMBUS)			+= slimbus.o
+slimbus-y				:= core.o
diff --git a/drivers/slimbus/core.c b/drivers/slimbus/core.c
new file mode 100644
index 000000000000..005714464fd8
--- /dev/null
+++ b/drivers/slimbus/core.c
@@ -0,0 +1,115 @@
+/* Copyright (c) 2011-2017, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/slimbus.h>
+
+static const struct slim_device_id *slim_match(const struct slim_device_id *id,
+					       const struct slim_device *sbdev)
+{
+	while (id->manf_id != 0 || id->prod_code != 0) {
+		if (id->manf_id == sbdev->e_addr.manf_id &&
+		    id->prod_code == sbdev->e_addr.prod_code)
+			return id;
+		id++;
+	}
+	return NULL;
+}
+
+static int slim_device_match(struct device *dev, struct device_driver *drv)
+{
+	struct slim_device *sbdev = to_slim_device(dev);
+	struct slim_driver *sbdrv = to_slim_driver(drv);
+
+	return !!slim_match(sbdrv->id_table, sbdev);
+}
+
+static int slim_device_probe(struct device *dev)
+{
+	struct slim_device	*sbdev = to_slim_device(dev);
+	struct slim_driver	*sbdrv = to_slim_driver(dev->driver);
+
+	return sbdrv->probe(sbdev);
+}
+
+static int slim_device_remove(struct device *dev)
+{
+	struct slim_device *sbdev = to_slim_device(dev);
+	struct slim_driver *sbdrv;
+
+	if (dev->driver) {
+		sbdrv = to_slim_driver(dev->driver);
+		if (sbdrv->remove)
+			sbdrv->remove(sbdev);
+	}
+
+	return 0;
+}
+
+struct bus_type slimbus_bus = {
+	.name		= "slimbus",
+	.match		= slim_device_match,
+	.probe		= slim_device_probe,
+	.remove		= slim_device_remove,
+};
+EXPORT_SYMBOL_GPL(slimbus_bus);
+
+/*
+ * __slim_driver_register() - Client driver registration with SLIMbus
+ *
+ * @drv:Client driver to be associated with client-device.
+ * @owner: owning module/driver
+ *
+ * This API will register the client driver with the SLIMbus
+ * It is called from the driver's module-init function.
+ */
+int __slim_driver_register(struct slim_driver *drv, struct module *owner)
+{
+	/* ID table and probe are mandatory */
+	if (!drv->id_table || !drv->probe)
+		return -EINVAL;
+
+	drv->driver.bus = &slimbus_bus;
+	drv->driver.owner = owner;
+
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(__slim_driver_register);
+
+/*
+ * slim_driver_unregister() - Undo effect of slim_driver_register
+ *
+ * @drv: Client driver to be unregistered
+ */
+void slim_driver_unregister(struct slim_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(slim_driver_unregister);
+
+static void __exit slimbus_exit(void)
+{
+	bus_unregister(&slimbus_bus);
+}
+module_exit(slimbus_exit);
+
+static int __init slimbus_init(void)
+{
+	return bus_register(&slimbus_bus);
+}
+postcore_initcall(slimbus_init);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("SLIMbus core");
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index abb6dc2ebbf8..48e188327c02 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -452,6 +452,19 @@ struct spi_device_id {
 	kernel_ulong_t driver_data;	/* Data private to the driver */
 };
 
+/* SLIMbus */
+
+#define SLIMBUS_NAME_SIZE	32
+#define SLIMBUS_MODULE_PREFIX	"slim:"
+
+struct slim_device_id {
+	__u16 manf_id, prod_code;
+	__u16 dev_index, instance;
+
+	/* Data private to the driver */
+	kernel_ulong_t driver_data;
+};
+
 #define SPMI_NAME_SIZE	32
 #define SPMI_MODULE_PREFIX "spmi:"
 
diff --git a/include/linux/slimbus.h b/include/linux/slimbus.h
new file mode 100644
index 000000000000..852cdb9f1abd
--- /dev/null
+++ b/include/linux/slimbus.h
@@ -0,0 +1,123 @@
+/* Copyright (c) 2011-2017, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#ifndef _LINUX_SLIMBUS_H
+#define _LINUX_SLIMBUS_H
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+
+extern struct bus_type slimbus_bus;
+
+/**
+ * struct slim_eaddr - Enumeration address for a SLIMbus device
+ * @manf_id: Manufacturer Id for the device
+ * @prod_code: Product code
+ * @dev_index: Device index
+ * @instance: Instance value
+ */
+struct slim_eaddr {
+	u16 manf_id;
+	u16 prod_code;
+	u8 dev_index;
+	u8 instance;
+} __packed;
+
+/**
+ * enum slim_device_status - slim device status
+ * @SLIM_DEVICE_STATUS_DOWN: Slim device is absent or not reported yet.
+ * @SLIM_DEVICE_STATUS_UP: Slim device is announced on the bus.
+ * @SLIM_DEVICE_STATUS_RESERVED: Reserved for future use.
+ */
+enum slim_device_status {
+	SLIM_DEVICE_STATUS_DOWN = 0,
+	SLIM_DEVICE_STATUS_UP,
+	SLIM_DEVICE_STATUS_RESERVED,
+};
+
+/**
+ * struct slim_device - Slim device handle.
+ * @dev: Driver model representation of the device.
+ * @e_addr: Enumeration address of this device.
+ * @status: slim device status
+ * @laddr: 1-byte Logical address of this device.
+ * @is_laddr_valid: indicates if the laddr is valid or not
+ *
+ * This is the client/device handle returned when a SLIMbus
+ * device is registered with a controller.
+ * Pointer to this structure is used by client-driver as a handle.
+ */
+struct slim_device {
+	struct device		dev;
+	struct slim_eaddr	e_addr;
+	enum slim_device_status	status;
+	u8			laddr;
+	bool			is_laddr_valid;
+};
+
+#define to_slim_device(d) container_of(d, struct slim_device, dev)
+
+/**
+ * struct slim_driver - SLIMbus 'generic device' (slave) device driver
+ *				(similar to 'spi_device' on SPI)
+ * @probe: Binds this driver to a SLIMbus device.
+ * @remove: Unbinds this driver from the SLIMbus device.
+ * @shutdown: Standard shutdown callback used during powerdown/halt.
+ * @device_status: This callback is called when
+ *	- The device reports present and gets a laddr assigned
+ *	- The device reports absent, or the bus goes down.
+ * @driver: SLIMbus device drivers should initialize name and owner field of
+ *	    this structure
+ * @id_table: List of SLIMbus devices supported by this driver
+ */
+
+struct slim_driver {
+	int	(*probe)(struct slim_device *sl);
+	void	(*remove)(struct slim_device *sl);
+	void	(*shutdown)(struct slim_device *sl);
+	int	(*device_status)(struct slim_device *sl,
+				 enum slim_device_status s);
+	struct device_driver		driver;
+	const struct slim_device_id	*id_table;
+};
+#define to_slim_driver(d) container_of(d, struct slim_driver, driver)
+
+/*
+ * use a macro to avoid include chaining to get THIS_MODULE
+ */
+#define slim_driver_register(drv) \
+	__slim_driver_register(drv, THIS_MODULE)
+int __slim_driver_register(struct slim_driver *drv, struct module *owner);
+void slim_driver_unregister(struct slim_driver *drv);
+
+/**
+ * module_slim_driver() - Helper macro for registering a SLIMbus driver
+ * @__slim_driver: slimbus_driver struct
+ *
+ * Helper macro for SLIMbus drivers which do not do anything special in module
+ * init/exit. This eliminates a lot of boilerplate. Each module may only
+ * use this macro once, and calling it replaces module_init() and module_exit()
+ */
+#define module_slim_driver(__slim_driver) \
+	module_driver(__slim_driver, slim_driver_register, \
+			slim_driver_unregister)
+
+static inline void *slim_get_devicedata(const struct slim_device *dev)
+{
+	return dev_get_drvdata(&dev->dev);
+}
+
+static inline void slim_set_devicedata(struct slim_device *dev, void *data)
+{
+	dev_set_drvdata(&dev->dev, data);
+}
+#endif /* _LINUX_SLIMBUS_H */
-- 
2.15.0

[PATCH v8 04/13] slimbus: core: Add slim controllers support

[srinivas.kandagatla]

From: Sagar Dharia <sdharia@codeaurora.org>

This patch adds support to slim controllers in the slim core,
including some utility functions invoked by the controller and
slim device drivers.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/slimbus/core.c    | 306 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/slimbus/slimbus.h | 115 +++++++++++++++++
 include/linux/slimbus.h   |   8 ++
 3 files changed, 429 insertions(+)
 create mode 100644 drivers/slimbus/slimbus.h

diff --git a/drivers/slimbus/core.c b/drivers/slimbus/core.c
index 005714464fd8..41e83c15591a 100644
--- a/drivers/slimbus/core.c
+++ b/drivers/slimbus/core.c
@@ -14,7 +14,11 @@
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/init.h>
+#include <linux/idr.h>
 #include <linux/slimbus.h>
+#include "slimbus.h"
+
+static DEFINE_IDA(ctrl_ida);
 
 static const struct slim_device_id *slim_match(const struct slim_device_id *id,
 					       const struct slim_device *sbdev)
@@ -99,6 +103,308 @@ void slim_driver_unregister(struct slim_driver *drv)
 }
 EXPORT_SYMBOL_GPL(slim_driver_unregister);
 
+static void slim_dev_release(struct device *dev)
+{
+	struct slim_device *sbdev = to_slim_device(dev);
+
+	kfree(sbdev);
+}
+
+static int slim_add_device(struct slim_controller *ctrl,
+			   struct slim_device *sbdev,
+			   struct device_node *node)
+{
+	sbdev->dev.bus = &slimbus_bus;
+	sbdev->dev.parent = ctrl->dev;
+	sbdev->dev.release = slim_dev_release;
+	sbdev->dev.driver = NULL;
+	sbdev->ctrl = ctrl;
+
+	dev_set_name(&sbdev->dev, "%x:%x:%x:%x",
+				  sbdev->e_addr.manf_id,
+				  sbdev->e_addr.prod_code,
+				  sbdev->e_addr.dev_index,
+				  sbdev->e_addr.instance);
+
+	return device_register(&sbdev->dev);
+}
+
+static struct slim_device *slim_alloc_device(struct slim_controller *ctrl,
+					     struct slim_eaddr *eaddr,
+					     struct device_node *node)
+{
+	struct slim_device *sbdev;
+	int ret;
+
+	sbdev = kzalloc(sizeof(*sbdev), GFP_KERNEL);
+	if (!sbdev)
+		return NULL;
+
+	sbdev->e_addr = *eaddr;
+	ret = slim_add_device(ctrl, sbdev, node);
+	if (ret) {
+		kfree(sbdev);
+		return NULL;
+	}
+
+	return sbdev;
+}
+
+/*
+ * slim_register_controller() - Controller bring-up and registration.
+ *
+ * @ctrl: Controller to be registered.
+ *
+ * A controller is registered with the framework using this API.
+ * If devices on a controller were registered before controller,
+ * this will make sure that they get probed when controller is up
+ */
+int slim_register_controller(struct slim_controller *ctrl)
+{
+	int id;
+
+	id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
+	if (id < 0)
+		return id;
+
+	ctrl->id = id;
+
+	if (!ctrl->min_cg)
+		ctrl->min_cg = SLIM_MIN_CLK_GEAR;
+	if (!ctrl->max_cg)
+		ctrl->max_cg = SLIM_MAX_CLK_GEAR;
+
+	ida_init(&ctrl->laddr_ida);
+	idr_init(&ctrl->tid_idr);
+	mutex_init(&ctrl->lock);
+
+	dev_dbg(ctrl->dev, "Bus [%s] registered:dev:%p\n",
+		ctrl->name, ctrl->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(slim_register_controller);
+
+/* slim_remove_device: Remove the effect of slim_add_device() */
+static void slim_remove_device(struct slim_device *sbdev)
+{
+	device_unregister(&sbdev->dev);
+}
+
+static int slim_ctrl_remove_device(struct device *dev, void *null)
+{
+	slim_remove_device(to_slim_device(dev));
+	return 0;
+}
+
+/**
+ * slim_unregister_controller() - Controller tear-down.
+ *
+ * @ctrl: Controller to tear-down.
+ */
+int slim_unregister_controller(struct slim_controller *ctrl)
+{
+	/* Remove all clients */
+	device_for_each_child(ctrl->dev, NULL, slim_ctrl_remove_device);
+	ida_simple_remove(&ctrl_ida, ctrl->id);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(slim_unregister_controller);
+
+static void slim_device_update_status(struct slim_device *sbdev,
+				      enum slim_device_status status)
+{
+	struct slim_driver *sbdrv;
+
+	if (sbdev->status == status)
+		return;
+
+	sbdev->status = status;
+	if (!sbdev->dev.driver)
+		return;
+
+	sbdrv = to_slim_driver(sbdev->dev.driver);
+	if (sbdrv->device_status)
+		sbdrv->device_status(sbdev, sbdev->status);
+}
+
+/**
+ * slim_report_absent() - Controller calls this function when a device
+ *	reports absent, OR when the device cannot be communicated with
+ *
+ * @sbdev: Device that cannot be reached, or sent report absent
+ */
+void slim_report_absent(struct slim_device *sbdev)
+{
+	struct slim_controller *ctrl = sbdev->ctrl;
+
+	if (!ctrl)
+		return;
+
+	/* invalidate logical addresses */
+	mutex_lock(&ctrl->lock);
+	sbdev->is_laddr_valid = false;
+	mutex_unlock(&ctrl->lock);
+
+	ida_simple_remove(&ctrl->laddr_ida, sbdev->laddr);
+	slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_DOWN);
+}
+EXPORT_SYMBOL_GPL(slim_report_absent);
+
+static bool slim_eaddr_equal(struct slim_eaddr *a, struct slim_eaddr *b)
+{
+	return (a->manf_id == b->manf_id &&
+		a->prod_code == b->prod_code &&
+		a->dev_index == b->dev_index &&
+		a->instance == b->instance);
+}
+
+static int slim_match_dev(struct device *dev, void *data)
+{
+	struct slim_eaddr *e_addr = data;
+	struct slim_device *sbdev = to_slim_device(dev);
+
+	return slim_eaddr_equal(&sbdev->e_addr, e_addr);
+}
+
+static struct slim_device *find_slim_device(struct slim_controller *ctrl,
+					    struct slim_eaddr *eaddr)
+{
+	struct slim_device *sbdev;
+	struct device *dev;
+
+	dev = device_find_child(ctrl->dev, eaddr, slim_match_dev);
+	if (dev) {
+		sbdev = to_slim_device(dev);
+		return sbdev;
+	}
+
+	return NULL;
+}
+
+/**
+ * slim_get_device() - get handle to a device.
+ *
+ * @ctrl: Controller on which this device will be added/queried
+ * @e_addr: Enumeration address of the device to be queried
+ *
+ * Return: pointer to a device if it has already reported. Creates a new
+ * device and returns pointer to it if the device has not yet enumerated.
+ */
+struct slim_device *slim_get_device(struct slim_controller *ctrl,
+				    struct slim_eaddr *e_addr)
+{
+	struct slim_device *sbdev;
+
+	sbdev = find_slim_device(ctrl, e_addr);
+	if (!sbdev) {
+		sbdev = slim_alloc_device(ctrl, e_addr, NULL);
+		if (!sbdev)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	return sbdev;
+}
+EXPORT_SYMBOL_GPL(slim_get_device);
+
+static int slim_device_alloc_laddr(struct slim_device *sbdev,
+				   bool report_present)
+{
+	struct slim_controller *ctrl = sbdev->ctrl;
+	u8 laddr;
+	int ret;
+
+	mutex_lock(&ctrl->lock);
+	if (ctrl->get_laddr) {
+		ret = ctrl->get_laddr(ctrl, &sbdev->e_addr, &laddr);
+		if (ret < 0)
+			goto err;
+	} else if (report_present) {
+		ret = ida_simple_get(&ctrl->laddr_ida,
+				     0, SLIM_LA_MANAGER - 1, GFP_KERNEL);
+		if (ret < 0)
+			goto err;
+
+		laddr = ret;
+	} else {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	if (ctrl->set_laddr) {
+		ret = ctrl->set_laddr(ctrl, &sbdev->e_addr, laddr);
+		if (ret) {
+			ret = -EINVAL;
+			goto err;
+		}
+	}
+
+	sbdev->laddr = laddr;
+	sbdev->is_laddr_valid = true;
+
+	slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_UP);
+
+	dev_dbg(ctrl->dev, "setting slimbus l-addr:%x, ea:%x,%x,%x,%x\n",
+		laddr, sbdev->e_addr.manf_id, sbdev->e_addr.prod_code,
+		sbdev->e_addr.dev_index, sbdev->e_addr.instance);
+
+err:
+	mutex_unlock(&ctrl->lock);
+	return ret;
+
+}
+
+/**
+ * slim_device_report_present() - Report enumerated device.
+ *
+ * @ctrl: Controller with which device is enumerated.
+ * @e_addr: Enumeration address of the device.
+ * @laddr: Return logical address (if valid flag is false)
+ *
+ * Called by controller in response to REPORT_PRESENT. Framework will assign
+ * a logical address to this enumeration address.
+ * Function returns -EXFULL to indicate that all logical addresses are already
+ * taken.
+ */
+int slim_device_report_present(struct slim_controller *ctrl,
+			       struct slim_eaddr *e_addr, u8 *laddr)
+{
+	struct slim_device *sbdev;
+	int ret;
+
+	sbdev = slim_get_device(ctrl, e_addr);
+	if (IS_ERR(sbdev))
+		return -ENODEV;
+
+	if (sbdev->is_laddr_valid) {
+		*laddr = sbdev->laddr;
+		return 0;
+	}
+
+	ret = slim_device_alloc_laddr(sbdev, true);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(slim_device_report_present);
+
+/**
+ * slim_get_logical_addr() - get/allocate logical address of a SLIMbus device.
+ *
+ * @sbdev: client handle requesting the address.
+ *
+ * Return: zero if a logical address is valid or a new logical address
+ * has been assigned. error code in case of error.
+ */
+int slim_get_logical_addr(struct slim_device *sbdev)
+{
+	if (!sbdev->is_laddr_valid)
+		return slim_device_alloc_laddr(sbdev, false);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(slim_get_logical_addr);
+
 static void __exit slimbus_exit(void)
 {
 	bus_unregister(&slimbus_bus);
diff --git a/drivers/slimbus/slimbus.h b/drivers/slimbus/slimbus.h
new file mode 100644
index 000000000000..aac23bedef28
--- /dev/null
+++ b/drivers/slimbus/slimbus.h
@@ -0,0 +1,115 @@
+/* Copyright (c) 2011-2017, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#ifndef _DRIVERS_SLIMBUS_H
+#define _DRIVERS_SLIMBUS_H
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/slimbus.h>
+
+/* Standard values per SLIMbus spec needed by controllers and devices */
+#define SLIM_MAX_CLK_GEAR		10
+#define SLIM_MIN_CLK_GEAR		1
+
+/* Manager's logical address is set to 0xFF per spec */
+#define SLIM_LA_MANAGER 0xFF
+
+/**
+ * struct slim_framer - Represents SLIMbus framer.
+ * Every controller may have multiple framers. There is 1 active framer device
+ * responsible for clocking the bus.
+ * Manager is responsible for framer hand-over.
+ * @dev: Driver model representation of the device.
+ * @e_addr: Enumeration address of the framer.
+ * @rootfreq: Root Frequency at which the framer can run. This is maximum
+ *	frequency ('clock gear 10') at which the bus can operate.
+ * @superfreq: Superframes per root frequency. Every frame is 6144 bits.
+ */
+struct slim_framer {
+	struct device		dev;
+	struct slim_eaddr	e_addr;
+	int			rootfreq;
+	int			superfreq;
+};
+
+#define to_slim_framer(d) container_of(d, struct slim_framer, dev)
+
+/**
+ * struct slim_controller  - Controls every instance of SLIMbus
+ *				(similar to 'master' on SPI)
+ * @dev: Device interface to this driver
+ * @id: Board-specific number identifier for this controller/bus
+ * @name: Name for this controller
+ * @min_cg: Minimum clock gear supported by this controller (default value: 1)
+ * @max_cg: Maximum clock gear supported by this controller (default value: 10)
+ * @clkgear: Current clock gear in which this bus is running
+ * @laddr_ida: logical address id allocator
+ * @a_framer: Active framer which is clocking the bus managed by this controller
+ * @lock: Mutex protecting controller data structures
+ * @devices: Slim device list
+ * @tid_idr: tid id allocator
+ * @txn_lock: Lock to protect table of transactions
+ * @set_laddr: Setup logical address at laddr for the slave with elemental
+ *	address e_addr. Drivers implementing controller will be expected to
+ *	send unicast message to this device with its logical address.
+ * @get_laddr: It is possible that controller needs to set fixed logical
+ *	address table and get_laddr can be used in that case so that controller
+ *	can do this assignment. Use case is when the master is on the remote
+ *	processor side, who is resposible for allocating laddr.
+ *
+ *	'Manager device' is responsible for  device management, bandwidth
+ *	allocation, channel setup, and port associations per channel.
+ *	Device management means Logical address assignment/removal based on
+ *	enumeration (report-present, report-absent) of a device.
+ *	Bandwidth allocation is done dynamically by the manager based on active
+ *	channels on the bus, message-bandwidth requests made by SLIMbus devices.
+ *	Based on current bandwidth usage, manager chooses a frequency to run
+ *	the bus at (in steps of 'clock-gear', 1 through 10, each clock gear
+ *	representing twice the frequency than the previous gear).
+ *	Manager is also responsible for entering (and exiting) low-power-mode
+ *	(known as 'clock pause').
+ *	Manager can do handover of framer if there are multiple framers on the
+ *	bus and a certain usecase warrants using certain framer to avoid keeping
+ *	previous framer being powered-on.
+ *
+ *	Controller here performs duties of the manager device, and 'interface
+ *	device'. Interface device is responsible for monitoring the bus and
+ *	reporting information such as loss-of-synchronization, data
+ *	slot-collision.
+ */
+struct slim_controller {
+	struct device		*dev;
+	unsigned int		id;
+	char			name[SLIMBUS_NAME_SIZE];
+	int			min_cg;
+	int			max_cg;
+	int			clkgear;
+	struct ida		laddr_ida;
+	struct slim_framer	*a_framer;
+	struct mutex		lock;
+	struct list_head	devices;
+	struct idr		tid_idr;
+	spinlock_t		txn_lock;
+	int			(*set_laddr)(struct slim_controller *ctrl,
+					     struct slim_eaddr *ea, u8 laddr);
+	int			(*get_laddr)(struct slim_controller *ctrl,
+					     struct slim_eaddr *ea, u8 *laddr);
+};
+
+int slim_device_report_present(struct slim_controller *ctrl,
+			       struct slim_eaddr *e_addr, u8 *laddr);
+void slim_report_absent(struct slim_device *sbdev);
+int slim_register_controller(struct slim_controller *ctrl);
+int slim_unregister_controller(struct slim_controller *ctrl);
+
+#endif /* _LINUX_SLIMBUS_H */
diff --git a/include/linux/slimbus.h b/include/linux/slimbus.h
index 852cdb9f1abd..2f1081667b43 100644
--- a/include/linux/slimbus.h
+++ b/include/linux/slimbus.h
@@ -44,11 +44,14 @@ enum slim_device_status {
 	SLIM_DEVICE_STATUS_RESERVED,
 };
 
+struct slim_controller;
+
 /**
  * struct slim_device - Slim device handle.
  * @dev: Driver model representation of the device.
  * @e_addr: Enumeration address of this device.
  * @status: slim device status
+ * @ctrl: slim controller instance.
  * @laddr: 1-byte Logical address of this device.
  * @is_laddr_valid: indicates if the laddr is valid or not
  *
@@ -59,6 +62,7 @@ enum slim_device_status {
 struct slim_device {
 	struct device		dev;
 	struct slim_eaddr	e_addr;
+	struct slim_controller	*ctrl;
 	enum slim_device_status	status;
 	u8			laddr;
 	bool			is_laddr_valid;
@@ -120,4 +124,8 @@ static inline void slim_set_devicedata(struct slim_device *dev, void *data)
 {
 	dev_set_drvdata(&dev->dev, data);
 }
+
+struct slim_device *slim_get_device(struct slim_controller *ctrl,
+				    struct slim_eaddr *e_addr);
+int slim_get_logical_addr(struct slim_device *sbdev);
 #endif /* _LINUX_SLIMBUS_H */
-- 
2.15.0

[PATCH v8 05/13] slimbus: core: add support to device tree helper

[srinivas.kandagatla]

From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

This patch adds support to parse slim devices from device tree.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/slimbus/core.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/drivers/slimbus/core.c b/drivers/slimbus/core.c
index 41e83c15591a..0c66f76b1a85 100644
--- a/drivers/slimbus/core.c
+++ b/drivers/slimbus/core.c
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/idr.h>
+#include <linux/of.h>
 #include <linux/slimbus.h>
 #include "slimbus.h"
 
@@ -120,6 +121,9 @@ static int slim_add_device(struct slim_controller *ctrl,
 	sbdev->dev.driver = NULL;
 	sbdev->ctrl = ctrl;
 
+	if (node)
+		sbdev->dev.of_node = of_node_get(node);
+
 	dev_set_name(&sbdev->dev, "%x:%x:%x:%x",
 				  sbdev->e_addr.manf_id,
 				  sbdev->e_addr.prod_code,
@@ -150,6 +154,50 @@ static struct slim_device *slim_alloc_device(struct slim_controller *ctrl,
 	return sbdev;
 }
 
+static void of_register_slim_devices(struct slim_controller *ctrl)
+{
+	struct device *dev = ctrl->dev;
+	struct device_node *node;
+
+	if (!ctrl->dev->of_node)
+		return;
+
+	for_each_child_of_node(ctrl->dev->of_node, node) {
+		struct slim_device *sbdev;
+		struct slim_eaddr e_addr;
+		const char *compat = NULL;
+		int reg[2], ret;
+		int manf_id, prod_code;
+
+		compat = of_get_property(node, "compatible", NULL);
+		if (!compat)
+			continue;
+
+		ret = sscanf(compat, "slim%x,%x", &manf_id, &prod_code);
+		if (ret != 2) {
+			dev_err(dev, "Manf ID & Product code not found %s\n",
+				compat);
+			continue;
+		}
+
+		ret = of_property_read_u32_array(node, "reg", reg, 2);
+		if (ret) {
+			dev_err(dev, "Device and Instance id not found:%d\n",
+				ret);
+			continue;
+		}
+
+		e_addr.dev_index = reg[0];
+		e_addr.instance = reg[1];
+		e_addr.manf_id = manf_id;
+		e_addr.prod_code = prod_code;
+
+		sbdev = slim_alloc_device(ctrl, &e_addr, node);
+		if (!sbdev)
+			continue;
+	}
+}
+
 /*
  * slim_register_controller() - Controller bring-up and registration.
  *
@@ -181,6 +229,8 @@ int slim_register_controller(struct slim_controller *ctrl)
 	dev_dbg(ctrl->dev, "Bus [%s] registered:dev:%p\n",
 		ctrl->name, ctrl->dev);
 
+	of_register_slim_devices(ctrl);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(slim_register_controller);
-- 
2.15.0

[PATCH v8 06/13] slimbus: Add messaging APIs to slimbus framework

[srinivas.kandagatla]

From: Sagar Dharia <sdharia@codeaurora.org>

SLIMbus devices use value-element, and information elements to
control device parameters (e.g. value element is used to represent
gain for codec, information element is used to represent interrupt
status for codec when codec interrupt fires).
Messaging APIs are used to set/get these value and information
elements. SLIMbus specification uses 8-bit "transaction IDs" for
messages where a read-value is anticipated. Framework uses a table
of pointers to store those TIDs and responds back to the caller in
O(1).
Caller can do synchronous and asynchronous reads/writes.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/slimbus/Makefile    |   2 +-
 drivers/slimbus/messaging.c | 303 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/slimbus/slimbus.h   |  67 ++++++++++
 include/linux/slimbus.h     |  40 ++++++
 4 files changed, 411 insertions(+), 1 deletion(-)
 create mode 100644 drivers/slimbus/messaging.c

diff --git a/drivers/slimbus/Makefile b/drivers/slimbus/Makefile
index 49ac5dce3fef..a65677ec3f7a 100644
--- a/drivers/slimbus/Makefile
+++ b/drivers/slimbus/Makefile
@@ -2,4 +2,4 @@
 # Makefile for kernel SLIMbus framework.
 #
 obj-$(CONFIG_SLIMBUS)			+= slimbus.o
-slimbus-y				:= core.o
+slimbus-y				:= core.o messaging.o
diff --git a/drivers/slimbus/messaging.c b/drivers/slimbus/messaging.c
new file mode 100644
index 000000000000..7c12dc933816
--- /dev/null
+++ b/drivers/slimbus/messaging.c
@@ -0,0 +1,303 @@
+/* Copyright (c) 2011-2017, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+#include <linux/slab.h>
+#include "slimbus.h"
+
+/**
+ * slim_msg_response() - Deliver Message response received from a device to the
+ *			framework.
+ *
+ * @ctrl: Controller handle
+ * @reply: Reply received from the device
+ * @len: Length of the reply
+ * @tid: Transaction ID received with which framework can associate reply.
+ *
+ * Called by controller to inform framework about the response received.
+ * This helps in making the API asynchronous, and controller-driver doesn't need
+ * to manage 1 more table other than the one managed by framework mapping TID
+ * with buffers
+ */
+void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 len)
+{
+	struct slim_msg_txn *txn;
+	struct slim_val_inf *msg;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ctrl->txn_lock, flags);
+	txn = idr_find(&ctrl->tid_idr, tid);
+	if (txn == NULL) {
+		spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+		return;
+	}
+
+	msg = txn->msg;
+	if (msg == NULL || msg->rbuf == NULL) {
+		dev_err(ctrl->dev, "Got response to invalid TID:%d, len:%d\n",
+				tid, len);
+		return;
+	}
+
+	idr_remove(&ctrl->tid_idr, tid);
+	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+
+	memcpy(msg->rbuf, reply, len);
+	if (txn->comp)
+		complete(txn->comp);
+}
+EXPORT_SYMBOL_GPL(slim_msg_response);
+
+/**
+ * slim_do_transfer() - Process a SLIMbus-messaging transaction
+ *
+ * @ctrl: Controller handle
+ * @txn: Transaction to be sent over SLIMbus
+ *
+ * Called by controller to transmit messaging transactions not dealing with
+ * Interface/Value elements. (e.g. transmittting a message to assign logical
+ * address to a slave device
+ *
+ * Return: -ETIMEDOUT: If transmission of this message timed out
+ *	(e.g. due to bus lines not being clocked or driven by controller)
+ */
+int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
+{
+	DECLARE_COMPLETION_ONSTACK(done);
+	bool need_tid;
+	unsigned long flags;
+	int ret, tid, timeout;
+
+	need_tid = slim_tid_txn(txn->mt, txn->mc);
+
+	if (need_tid) {
+		spin_lock_irqsave(&ctrl->txn_lock, flags);
+		tid = idr_alloc(&ctrl->tid_idr, txn, 0,
+				SLIM_MAX_TIDS, GFP_KERNEL);
+		txn->tid = tid;
+
+		if (!txn->msg->comp)
+			txn->comp = &done;
+		else
+			txn->comp = txn->comp;
+
+		spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+
+		if (tid < 0)
+			return tid;
+	}
+
+	ret = ctrl->xfer_msg(ctrl, txn);
+
+	if (ret && need_tid && !txn->msg->comp) {
+		unsigned long ms = txn->rl + HZ;
+
+		timeout = wait_for_completion_timeout(txn->comp,
+						      msecs_to_jiffies(ms));
+		if (!timeout) {
+			ret = -ETIMEDOUT;
+			spin_lock_irqsave(&ctrl->txn_lock, flags);
+			idr_remove(&ctrl->tid_idr, tid);
+			spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+		}
+	}
+
+	if (ret)
+		dev_err(ctrl->dev, "Tx:MT:0x%x, MC:0x%x, LA:0x%x failed:%d\n",
+			txn->mt, txn->mc, txn->la, ret);
+
+	return ret;
+}
+
+static int slim_val_inf_sanity(struct slim_controller *ctrl,
+			       struct slim_val_inf *msg, u8 mc)
+{
+	if (!msg || msg->num_bytes > 16 ||
+	    (msg->start_offset + msg->num_bytes) > 0xC00)
+		goto reterr;
+	switch (mc) {
+	case SLIM_MSG_MC_REQUEST_VALUE:
+	case SLIM_MSG_MC_REQUEST_INFORMATION:
+		if (msg->rbuf != NULL)
+			return 0;
+		break;
+
+	case SLIM_MSG_MC_CHANGE_VALUE:
+	case SLIM_MSG_MC_CLEAR_INFORMATION:
+		if (msg->wbuf != NULL)
+			return 0;
+		break;
+
+	case SLIM_MSG_MC_REQUEST_CHANGE_VALUE:
+	case SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION:
+		if (msg->rbuf != NULL && msg->wbuf != NULL)
+			return 0;
+		break;
+	}
+reterr:
+	dev_err(ctrl->dev, "Sanity check failed:msg:offset:0x%x, mc:%d\n",
+		msg->start_offset, mc);
+	return -EINVAL;
+}
+
+static u16 slim_slicesize(int code)
+{
+	static const u8 sizetocode[16] = {
+		0, 1, 2, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7
+	};
+
+	clamp(code, 1, (int)ARRAY_SIZE(sizetocode));
+
+	return sizetocode[code - 1];
+}
+
+/**
+ * slim_xfer_msg() - Transfer a value info message on slim device
+ *
+ * @sbdev: slim device to which this msg has to be transfered
+ * @msg: value info message pointer
+ * @mc: message code of the message
+ *
+ * Called by drivers which want to transfer a vlaue or info elements.
+ *
+ * Return: -ETIMEDOUT: If transmission of this message timed out
+ */
+int slim_xfer_msg(struct slim_device *sbdev, struct slim_val_inf *msg,
+		  u8 mc)
+{
+	DEFINE_SLIM_LDEST_TXN(txn_stack, mc, 6, sbdev->laddr, msg);
+	struct slim_msg_txn *txn = &txn_stack;
+	struct slim_controller *ctrl = sbdev->ctrl;
+	int ret;
+	u16 sl;
+
+	if (!ctrl)
+		return -EINVAL;
+
+	ret = slim_val_inf_sanity(ctrl, msg, mc);
+	if (ret)
+		return ret;
+
+	sl = slim_slicesize(msg->num_bytes);
+
+	dev_dbg(ctrl->dev, "SB xfer msg:os:%x, len:%d, MC:%x, sl:%x\n",
+		msg->start_offset, msg->num_bytes, mc, sl);
+
+	txn->ec = ((sl | (1 << 3)) | ((msg->start_offset & 0xFFF) << 4));
+
+	switch (mc) {
+	case SLIM_MSG_MC_REQUEST_CHANGE_VALUE:
+	case SLIM_MSG_MC_CHANGE_VALUE:
+	case SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION:
+	case SLIM_MSG_MC_CLEAR_INFORMATION:
+		txn->rl += msg->num_bytes;
+	default:
+		break;
+	}
+
+	if (slim_tid_txn(txn->mt, txn->mc))
+		txn->rl++;
+
+	return slim_do_transfer(ctrl, txn);
+}
+
+static void slim_fill_msg(struct slim_val_inf *msg, u32 addr,
+			 size_t count, u8 *rbuf, u8 *wbuf)
+{
+	msg->start_offset = addr;
+	msg->num_bytes = count;
+	msg->rbuf = rbuf;
+	msg->wbuf = wbuf;
+}
+
+/**
+ * slim_read() - Read SLIMbus value element
+ *
+ * @sdev: client handle.
+ * @addr:  address of value element to read.
+ * @count: number of bytes to read. Maximum bytes allowed are 16.
+ * @val: will return what the value element value was
+ *
+ * Return:
+ *	- EINVAL: Invalid parameters
+ *	- ETIMEDOUT: If transmission of this message timed out (e.g. due to
+ *	 bus lines not being clocked or driven by controller)
+ */
+int slim_read(struct slim_device *sdev, u32 addr, size_t count, u8 *val)
+{
+	struct slim_val_inf msg;
+
+	slim_fill_msg(&msg, addr, count, val, NULL);
+
+	return slim_xfer_msg(sdev, &msg, SLIM_MSG_MC_REQUEST_VALUE);
+}
+EXPORT_SYMBOL_GPL(slim_read);
+
+/**
+ * slim_readb() - Read byte from SLIMbus value element
+ *
+ * @sdev: client handle.
+ * @addr:  address in the value element to read.
+ *
+ * Return: byte value of value element.
+ */
+int slim_readb(struct slim_device *sdev, u32 addr)
+{
+	int ret;
+	u8 buf;
+
+	ret = slim_read(sdev, addr, 1, &buf);
+	if (ret < 0)
+		return ret;
+	else
+		return buf;
+}
+EXPORT_SYMBOL_GPL(slim_readb);
+
+/**
+ * slim_write() - Write SLIMbus value element
+ *
+ * @sdev: client handle.
+ * @addr:  address in the value element to write.
+ * @count: number of bytes to write. Maximum bytes allowed are 16.
+ * @val: value to write to value element
+ *
+ * Return:
+ *	- EINVAL: Invalid parameters
+ *	- ETIMEDOUT: If transmission of this message timed out (e.g. due to
+ *	 bus lines not being clocked or driven by controller)
+ */
+int slim_write(struct slim_device *sdev, u32 addr, size_t count, u8 *val)
+{
+	struct slim_val_inf msg;
+
+	slim_fill_msg(&msg, addr, count,  val, NULL);
+
+	return slim_xfer_msg(sdev, &msg, SLIM_MSG_MC_CHANGE_VALUE);
+}
+EXPORT_SYMBOL_GPL(slim_write);
+
+/**
+ * slim_writeb() - Write byte to SLIMbus value element
+ *
+ * @sdev: client handle.
+ * @addr:  address of value element to write.
+ * @value: value to write to value element
+ *
+ * Return:
+ *	- EINVAL: Invalid parameters
+ *	- ETIMEDOUT: If transmission of this message timed out (e.g. due to
+ *	 bus lines not being clocked or driven by controller)
+ */
+int slim_writeb(struct slim_device *sdev, u32 addr, u8 value)
+{
+	return slim_write(sdev, addr, 1, &value);
+}
+EXPORT_SYMBOL_GPL(slim_writeb);
diff --git a/drivers/slimbus/slimbus.h b/drivers/slimbus/slimbus.h
index aac23bedef28..5a83ce15c63a 100644
--- a/drivers/slimbus/slimbus.h
+++ b/drivers/slimbus/slimbus.h
@@ -15,8 +15,17 @@
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/mutex.h>
+#include <linux/completion.h>
 #include <linux/slimbus.h>
 
+/* SLIMbus message types. Related to interpretation of message code. */
+#define SLIM_MSG_MT_CORE			0x0
+
+/* Destination type Values */
+#define SLIM_MSG_DEST_LOGICALADDR	0
+#define SLIM_MSG_DEST_ENUMADDR		1
+#define	SLIM_MSG_DEST_BROADCAST		3
+
 /* Standard values per SLIMbus spec needed by controllers and devices */
 #define SLIM_MAX_CLK_GEAR		10
 #define SLIM_MIN_CLK_GEAR		1
@@ -24,6 +33,7 @@
 /* Manager's logical address is set to 0xFF per spec */
 #define SLIM_LA_MANAGER 0xFF
 
+#define SLIM_MAX_TIDS			256
 /**
  * struct slim_framer - Represents SLIMbus framer.
  * Every controller may have multiple framers. There is 1 active framer device
@@ -44,6 +54,39 @@ struct slim_framer {
 
 #define to_slim_framer(d) container_of(d, struct slim_framer, dev)
 
+/**
+ * struct slim_msg_txn - Message to be sent by the controller.
+ *			This structure has packet header,
+ *			payload and buffer to be filled (if any)
+ * @rl: Header field. remaining length.
+ * @mt: Header field. Message type.
+ * @mc: Header field. LSB is message code for type mt.
+ * @dt: Header field. Destination type.
+ * @ec: Element code. Used for elemental access APIs.
+ * @tid: Transaction ID. Used for messages expecting response.
+ *	(relevant for message-codes involving read operation)
+ * @la: Logical address of the device this message is going to.
+ *	(Not used when destination type is broadcast.)
+ * @msg: Elemental access message to be read/written
+ * @comp: completion if read/write is synchronous, used internally
+ *	for tid based transactions.
+ */
+struct slim_msg_txn {
+	u8			rl;
+	u8			mt;
+	u8			mc;
+	u8			dt;
+	u16			ec;
+	u8			tid;
+	u8			la;
+	struct slim_val_inf	*msg;
+	struct	completion	*comp;
+};
+
+/* Frequently used message transaction structures */
+#define DEFINE_SLIM_LDEST_TXN(name, mc, rl, la, msg) \
+	struct slim_msg_txn name = { rl, 0, mc, SLIM_MSG_DEST_LOGICALADDR, 0,\
+					0, la, msg, }
 /**
  * struct slim_controller  - Controls every instance of SLIMbus
  *				(similar to 'master' on SPI)
@@ -59,6 +102,9 @@ struct slim_framer {
  * @devices: Slim device list
  * @tid_idr: tid id allocator
  * @txn_lock: Lock to protect table of transactions
+ * @xfer_msg: Transfer a message on this controller (this can be a broadcast
+ *	control/status message like data channel setup, or a unicast message
+ *	like value element read/write.
  * @set_laddr: Setup logical address at laddr for the slave with elemental
  *	address e_addr. Drivers implementing controller will be expected to
  *	send unicast message to this device with its logical address.
@@ -100,6 +146,8 @@ struct slim_controller {
 	struct list_head	devices;
 	struct idr		tid_idr;
 	spinlock_t		txn_lock;
+	int			(*xfer_msg)(struct slim_controller *ctrl,
+					    struct slim_msg_txn *tx);
 	int			(*set_laddr)(struct slim_controller *ctrl,
 					     struct slim_eaddr *ea, u8 laddr);
 	int			(*get_laddr)(struct slim_controller *ctrl,
@@ -111,5 +159,24 @@ int slim_device_report_present(struct slim_controller *ctrl,
 void slim_report_absent(struct slim_device *sbdev);
 int slim_register_controller(struct slim_controller *ctrl);
 int slim_unregister_controller(struct slim_controller *ctrl);
+void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 l);
+int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn);
+
+static inline bool slim_tid_txn(u8 mt, u8 mc)
+{
+	return (mt == SLIM_MSG_MT_CORE &&
+		(mc == SLIM_MSG_MC_REQUEST_INFORMATION ||
+		 mc == SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION ||
+		 mc == SLIM_MSG_MC_REQUEST_VALUE ||
+		 mc == SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION));
+}
 
+static inline bool slim_ec_txn(u8 mt, u8 mc)
+{
+	return (mt == SLIM_MSG_MT_CORE &&
+		((mc >= SLIM_MSG_MC_REQUEST_INFORMATION &&
+		  mc <= SLIM_MSG_MC_REPORT_INFORMATION) ||
+		 (mc >= SLIM_MSG_MC_REQUEST_VALUE &&
+		  mc <= SLIM_MSG_MC_CHANGE_VALUE)));
+}
 #endif /* _LINUX_SLIMBUS_H */
diff --git a/include/linux/slimbus.h b/include/linux/slimbus.h
index 2f1081667b43..f09327e472cf 100644
--- a/include/linux/slimbus.h
+++ b/include/linux/slimbus.h
@@ -14,6 +14,7 @@
 #define _LINUX_SLIMBUS_H
 #include <linux/device.h>
 #include <linux/module.h>
+#include <linux/completion.h>
 #include <linux/mod_devicetable.h>
 
 extern struct bus_type slimbus_bus;
@@ -95,6 +96,25 @@ struct slim_driver {
 };
 #define to_slim_driver(d) container_of(d, struct slim_driver, driver)
 
+/**
+ * struct slim_val_inf - Slimbus value or information element
+ * @start_offset: Specifies starting offset in information/value element map
+ * @rbuf: buffer to read the values
+ * @wbuf: buffer to write
+ * @num_bytes: upto 16. This ensures that the message will fit the slicesize
+ *		per SLIMbus spec
+ * @comp: completion for asynchronous operations, valid only if TID is
+ *	  required for transaction, like REQUEST operations.
+ *	  Rest of the transactions are synchronous anyway.
+ */
+struct slim_val_inf {
+	u16			start_offset;
+	u8			num_bytes;
+	u8			*rbuf;
+	const u8		*wbuf;
+	struct	completion	*comp;
+};
+
 /*
  * use a macro to avoid include chaining to get THIS_MODULE
  */
@@ -128,4 +148,24 @@ static inline void slim_set_devicedata(struct slim_device *dev, void *data)
 struct slim_device *slim_get_device(struct slim_controller *ctrl,
 				    struct slim_eaddr *e_addr);
 int slim_get_logical_addr(struct slim_device *sbdev);
+
+/* Information Element management messages */
+#define SLIM_MSG_MC_REQUEST_INFORMATION          0x20
+#define SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION    0x21
+#define SLIM_MSG_MC_REPLY_INFORMATION            0x24
+#define SLIM_MSG_MC_CLEAR_INFORMATION            0x28
+#define SLIM_MSG_MC_REPORT_INFORMATION           0x29
+
+/* Value Element management messages */
+#define SLIM_MSG_MC_REQUEST_VALUE                0x60
+#define SLIM_MSG_MC_REQUEST_CHANGE_VALUE         0x61
+#define SLIM_MSG_MC_REPLY_VALUE                  0x64
+#define SLIM_MSG_MC_CHANGE_VALUE                 0x68
+
+int slim_xfer_msg(struct slim_device *sbdev, struct slim_val_inf *msg,
+		  u8 mc);
+int slim_readb(struct slim_device *sdev, u32 addr);
+int slim_writeb(struct slim_device *sdev, u32 addr, u8 value);
+int slim_read(struct slim_device *sdev, u32 addr, size_t count, u8 *val);
+int slim_write(struct slim_device *sdev, u32 addr, size_t count, u8 *val);
 #endif /* _LINUX_SLIMBUS_H */
-- 
2.15.0

[PATCH v8 07/13] slimbus: Add support for 'clock-pause' feature

[srinivas.kandagatla]

From: Sagar Dharia <sdharia@codeaurora.org>

Per SLIMbus specification, a reconfiguration sequence known as
'clock pause' needs to be broadcast over the bus while entering low-
power mode. Clock-pause is initiated by the controller driver.
To exit clock-pause, controller typically wakes up the framer device.
Since wakeup precedure is controller-specific, framework calls it via
controller's function pointer to invoke it.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/slimbus/Makefile    |   2 +-
 drivers/slimbus/core.c      |  16 ++++++
 drivers/slimbus/messaging.c |  35 +++++++++++-
 drivers/slimbus/sched.c     | 128 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/slimbus/slimbus.h   |  53 ++++++++++++++++++
 5 files changed, 232 insertions(+), 2 deletions(-)
 create mode 100644 drivers/slimbus/sched.c

diff --git a/drivers/slimbus/Makefile b/drivers/slimbus/Makefile
index a65677ec3f7a..fd794f83d1cf 100644
--- a/drivers/slimbus/Makefile
+++ b/drivers/slimbus/Makefile
@@ -2,4 +2,4 @@
 # Makefile for kernel SLIMbus framework.
 #
 obj-$(CONFIG_SLIMBUS)			+= slimbus.o
-slimbus-y				:= core.o messaging.o
+slimbus-y				:= core.o messaging.o sched.o
diff --git a/drivers/slimbus/core.c b/drivers/slimbus/core.c
index 0c66f76b1a85..17485b0d0771 100644
--- a/drivers/slimbus/core.c
+++ b/drivers/slimbus/core.c
@@ -16,6 +16,7 @@
 #include <linux/init.h>
 #include <linux/idr.h>
 #include <linux/of.h>
+#include <linux/pm_runtime.h>
 #include <linux/slimbus.h>
 #include "slimbus.h"
 
@@ -225,6 +226,8 @@ int slim_register_controller(struct slim_controller *ctrl)
 	ida_init(&ctrl->laddr_ida);
 	idr_init(&ctrl->tid_idr);
 	mutex_init(&ctrl->lock);
+	mutex_init(&ctrl->sched.m_reconf);
+	init_completion(&ctrl->sched.pause_comp);
 
 	dev_dbg(ctrl->dev, "Bus [%s] registered:dev:%p\n",
 		ctrl->name, ctrl->dev);
@@ -256,6 +259,8 @@ int slim_unregister_controller(struct slim_controller *ctrl)
 {
 	/* Remove all clients */
 	device_for_each_child(ctrl->dev, NULL, slim_ctrl_remove_device);
+	/* Enter Clock Pause */
+	slim_ctrl_clk_pause(ctrl, false, 0);
 	ida_simple_remove(&ctrl_ida, ctrl->id);
 
 	return 0;
@@ -423,6 +428,14 @@ int slim_device_report_present(struct slim_controller *ctrl,
 	struct slim_device *sbdev;
 	int ret;
 
+	ret = pm_runtime_get_sync(ctrl->dev);
+
+	if (ctrl->sched.clk_state != SLIM_CLK_ACTIVE) {
+		dev_err(ctrl->dev, "slim ctrl not active,state:%d, ret:%d\n",
+				    ctrl->sched.clk_state, ret);
+		goto slimbus_not_active;
+	}
+
 	sbdev = slim_get_device(ctrl, e_addr);
 	if (IS_ERR(sbdev))
 		return -ENODEV;
@@ -434,6 +447,9 @@ int slim_device_report_present(struct slim_controller *ctrl,
 
 	ret = slim_device_alloc_laddr(sbdev, true);
 
+slimbus_not_active:
+	pm_runtime_mark_last_busy(ctrl->dev);
+	pm_runtime_put_autosuspend(ctrl->dev);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(slim_device_report_present);
diff --git a/drivers/slimbus/messaging.c b/drivers/slimbus/messaging.c
index 7c12dc933816..5f3bab2cd9e3 100644
--- a/drivers/slimbus/messaging.c
+++ b/drivers/slimbus/messaging.c
@@ -10,6 +10,7 @@
  * GNU General Public License for more details.
  */
 #include <linux/slab.h>
+#include <linux/pm_runtime.h>
 #include "slimbus.h"
 
 /**
@@ -52,6 +53,10 @@ void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 len)
 	memcpy(msg->rbuf, reply, len);
 	if (txn->comp)
 		complete(txn->comp);
+
+	/* Remove runtime-pm vote now that response was received for TID txn */
+	pm_runtime_mark_last_busy(ctrl->dev);
+	pm_runtime_put_autosuspend(ctrl->dev);
 }
 EXPORT_SYMBOL_GPL(slim_msg_response);
 
@@ -71,10 +76,29 @@ EXPORT_SYMBOL_GPL(slim_msg_response);
 int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
 {
 	DECLARE_COMPLETION_ONSTACK(done);
-	bool need_tid;
+	bool need_tid, clk_pause_msg = false;
 	unsigned long flags;
 	int ret, tid, timeout;
 
+	/*
+	 * do not vote for runtime-PM if the transactions are part of clock
+	 * pause sequence
+	 */
+	if (ctrl->sched.clk_state == SLIM_CLK_ENTERING_PAUSE &&
+		(txn->mt == SLIM_MSG_MT_CORE &&
+		 txn->mc >= SLIM_MSG_MC_BEGIN_RECONFIGURATION &&
+		 txn->mc <= SLIM_MSG_MC_RECONFIGURE_NOW))
+		clk_pause_msg = true;
+
+	if (!clk_pause_msg) {
+		ret = pm_runtime_get_sync(ctrl->dev);
+		if (ctrl->sched.clk_state != SLIM_CLK_ACTIVE) {
+			dev_err(ctrl->dev, "ctrl wrong state:%d, ret:%d\n",
+				ctrl->sched.clk_state, ret);
+			goto slim_xfer_err;
+		}
+	}
+
 	need_tid = slim_tid_txn(txn->mt, txn->mc);
 
 	if (need_tid) {
@@ -113,6 +137,15 @@ int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
 		dev_err(ctrl->dev, "Tx:MT:0x%x, MC:0x%x, LA:0x%x failed:%d\n",
 			txn->mt, txn->mc, txn->la, ret);
 
+slim_xfer_err:
+	if (!clk_pause_msg && (!need_tid  || ret == -ETIMEDOUT)) {
+		/*
+		 * remove runtime-pm vote if this was TX only, or
+		 * if there was error during this transaction
+		 */
+		pm_runtime_mark_last_busy(ctrl->dev);
+		pm_runtime_mark_last_busy(ctrl->dev);
+	}
 	return ret;
 }
 
diff --git a/drivers/slimbus/sched.c b/drivers/slimbus/sched.c
new file mode 100644
index 000000000000..74300f1a6898
--- /dev/null
+++ b/drivers/slimbus/sched.c
@@ -0,0 +1,128 @@
+/* Copyright (c) 2011-2016, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#include <linux/errno.h>
+#include "slimbus.h"
+
+/**
+ * slim_ctrl_clk_pause() - Called by slimbus controller to enter/exit
+ *			   'clock pause'
+ * @ctrl: controller requesting bus to be paused or woken up
+ * @wakeup: Wakeup this controller from clock pause.
+ * @restart: Restart time value per spec used for clock pause. This value
+ *	isn't used when controller is to be woken up.
+ *
+ * Slimbus specification needs this sequence to turn-off clocks for the bus.
+ * The sequence involves sending 3 broadcast messages (reconfiguration
+ * sequence) to inform all devices on the bus.
+ * To exit clock-pause, controller typically wakes up active framer device.
+ * This API executes clock pause reconfiguration sequence if wakeup is false.
+ * If wakeup is true, controller's wakeup is called.
+ * For entering clock-pause, -EBUSY is returned if a message txn in pending.
+ */
+int slim_ctrl_clk_pause(struct slim_controller *ctrl, bool wakeup, u8 restart)
+{
+	int i, ret = 0;
+	unsigned long flags;
+	struct slim_sched *sched = &ctrl->sched;
+	struct slim_val_inf msg = {0, 0, NULL, NULL};
+
+	DEFINE_SLIM_BCAST_TXN(txn, SLIM_MSG_MC_BEGIN_RECONFIGURATION,
+				3, SLIM_LA_MANAGER, &msg);
+
+	if (wakeup == false && restart > SLIM_CLK_UNSPECIFIED)
+		return -EINVAL;
+
+	mutex_lock(&sched->m_reconf);
+	if (wakeup) {
+		if (sched->clk_state == SLIM_CLK_ACTIVE) {
+			mutex_unlock(&sched->m_reconf);
+			return 0;
+		}
+
+		/*
+		 * Fine-tune calculation based on clock gear,
+		 * message-bandwidth after bandwidth management
+		 */
+		ret = wait_for_completion_timeout(&sched->pause_comp,
+				msecs_to_jiffies(100));
+		if (!ret) {
+			mutex_unlock(&sched->m_reconf);
+			pr_err("Previous clock pause did not finish");
+			return -ETIMEDOUT;
+		}
+		ret = 0;
+
+		/*
+		 * Slimbus framework will call controller wakeup
+		 * Controller should make sure that it sets active framer
+		 * out of clock pause
+		 */
+		if (sched->clk_state == SLIM_CLK_PAUSED && ctrl->wakeup)
+			ret = ctrl->wakeup(ctrl);
+		if (!ret)
+			sched->clk_state = SLIM_CLK_ACTIVE;
+		mutex_unlock(&sched->m_reconf);
+
+		return ret;
+	}
+
+	/* already paused */
+	if (ctrl->sched.clk_state == SLIM_CLK_PAUSED) {
+		mutex_unlock(&sched->m_reconf);
+		return 0;
+	}
+
+	spin_lock_irqsave(&ctrl->txn_lock, flags);
+	for (i = 0; i < SLIM_MAX_TIDS; i++) {
+		/* Pending response for a message */
+		if (idr_find(&ctrl->tid_idr, i)) {
+			spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+			mutex_unlock(&sched->m_reconf);
+			return -EBUSY;
+		}
+	}
+	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+
+	sched->clk_state = SLIM_CLK_ENTERING_PAUSE;
+
+	/* clock pause sequence */
+	ret = slim_do_transfer(ctrl, &txn);
+	if (ret)
+		goto clk_pause_ret;
+
+	txn.mc = SLIM_MSG_MC_NEXT_PAUSE_CLOCK;
+	txn.rl = 4;
+	msg.num_bytes = 1;
+	msg.wbuf = &restart;
+	ret = slim_do_transfer(ctrl, &txn);
+	if (ret)
+		goto clk_pause_ret;
+
+	txn.mc = SLIM_MSG_MC_RECONFIGURE_NOW;
+	txn.rl = 3;
+	msg.num_bytes = 1;
+	msg.wbuf = NULL;
+	ret = slim_do_transfer(ctrl, &txn);
+
+clk_pause_ret:
+	if (ret) {
+		sched->clk_state = SLIM_CLK_ACTIVE;
+	} else {
+		sched->clk_state = SLIM_CLK_PAUSED;
+		complete(&sched->pause_comp);
+	}
+	mutex_unlock(&sched->m_reconf);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(slim_ctrl_clk_pause);
diff --git a/drivers/slimbus/slimbus.h b/drivers/slimbus/slimbus.h
index 5a83ce15c63a..e0ae7bb1ba47 100644
--- a/drivers/slimbus/slimbus.h
+++ b/drivers/slimbus/slimbus.h
@@ -21,6 +21,16 @@
 /* SLIMbus message types. Related to interpretation of message code. */
 #define SLIM_MSG_MT_CORE			0x0
 
+/* Clock pause Reconfiguration messages */
+#define SLIM_MSG_MC_BEGIN_RECONFIGURATION        0x40
+#define SLIM_MSG_MC_NEXT_PAUSE_CLOCK             0x4A
+#define SLIM_MSG_MC_RECONFIGURE_NOW              0x5F
+
+/* Clock pause values per SLIMbus spec */
+#define SLIM_CLK_FAST				0
+#define SLIM_CLK_CONST_PHASE			1
+#define SLIM_CLK_UNSPECIFIED			2
+
 /* Destination type Values */
 #define SLIM_MSG_DEST_LOGICALADDR	0
 #define SLIM_MSG_DEST_ENUMADDR		1
@@ -87,6 +97,42 @@ struct slim_msg_txn {
 #define DEFINE_SLIM_LDEST_TXN(name, mc, rl, la, msg) \
 	struct slim_msg_txn name = { rl, 0, mc, SLIM_MSG_DEST_LOGICALADDR, 0,\
 					0, la, msg, }
+
+#define DEFINE_SLIM_BCAST_TXN(name, mc, rl, la, msg) \
+	struct slim_msg_txn name = { rl, 0, mc, SLIM_MSG_DEST_BROADCAST, 0,\
+					0, la, msg, }
+/**
+ * enum slim_clk_state: SLIMbus controller's clock state used internally for
+ *	maintaining current clock state.
+ * @SLIM_CLK_ACTIVE: SLIMbus clock is active
+ * @SLIM_CLK_ENTERING_PAUSE: SLIMbus clock pause sequence is being sent on the
+ *	bus. If this succeeds, state changes to SLIM_CLK_PAUSED. If the
+ *	transition fails, state changes back to SLIM_CLK_ACTIVE
+ * @SLIM_CLK_PAUSED: SLIMbus controller clock has paused.
+ */
+enum slim_clk_state {
+	SLIM_CLK_ACTIVE,
+	SLIM_CLK_ENTERING_PAUSE,
+	SLIM_CLK_PAUSED,
+};
+
+/**
+ * struct slim_sched: Framework uses this structure internally for scheduling.
+ * @clk_state: Controller's clock state from enum slim_clk_state
+ * @pause_comp: Signals completion of clock pause sequence. This is useful when
+ *	client tries to call SLIMbus transaction when controller is entering
+ *	clock pause.
+ * @m_reconf: This mutex is held until current reconfiguration (data channel
+ *	scheduling, message bandwidth reservation) is done. Message APIs can
+ *	use the bus concurrently when this mutex is held since elemental access
+ *	messages can be sent on the bus when reconfiguration is in progress.
+ */
+struct slim_sched {
+	enum slim_clk_state	clk_state;
+	struct completion	pause_comp;
+	struct mutex		m_reconf;
+};
+
 /**
  * struct slim_controller  - Controls every instance of SLIMbus
  *				(similar to 'master' on SPI)
@@ -102,6 +148,7 @@ struct slim_msg_txn {
  * @devices: Slim device list
  * @tid_idr: tid id allocator
  * @txn_lock: Lock to protect table of transactions
+ * @sched: scheduler structure used by the controller
  * @xfer_msg: Transfer a message on this controller (this can be a broadcast
  *	control/status message like data channel setup, or a unicast message
  *	like value element read/write.
@@ -112,6 +159,9 @@ struct slim_msg_txn {
  *	address table and get_laddr can be used in that case so that controller
  *	can do this assignment. Use case is when the master is on the remote
  *	processor side, who is resposible for allocating laddr.
+ * @wakeup: This function pointer implements controller-specific procedure
+ *	to wake it up from clock-pause. Framework will call this to bring
+ *	the controller out of clock pause.
  *
  *	'Manager device' is responsible for  device management, bandwidth
  *	allocation, channel setup, and port associations per channel.
@@ -146,12 +196,14 @@ struct slim_controller {
 	struct list_head	devices;
 	struct idr		tid_idr;
 	spinlock_t		txn_lock;
+	struct slim_sched	sched;
 	int			(*xfer_msg)(struct slim_controller *ctrl,
 					    struct slim_msg_txn *tx);
 	int			(*set_laddr)(struct slim_controller *ctrl,
 					     struct slim_eaddr *ea, u8 laddr);
 	int			(*get_laddr)(struct slim_controller *ctrl,
 					     struct slim_eaddr *ea, u8 *laddr);
+	int			(*wakeup)(struct slim_controller *ctrl);
 };
 
 int slim_device_report_present(struct slim_controller *ctrl,
@@ -161,6 +213,7 @@ int slim_register_controller(struct slim_controller *ctrl);
 int slim_unregister_controller(struct slim_controller *ctrl);
 void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 l);
 int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn);
+int slim_ctrl_clk_pause(struct slim_controller *ctrl, bool wakeup, u8 restart);
 
 static inline bool slim_tid_txn(u8 mt, u8 mc)
 {
-- 
2.15.0

[PATCH v8 08/13] regmap: add SLIMbus support

[srinivas.kandagatla]

From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

This patch adds support to read/write SLIMbus value elements.
Currently it only supports byte read/write. Adding this support in
regmap would give codec drivers more flexibility when there are more
than 2 control interfaces like SLIMbus, i2c.

Without this patch each codec driver has to directly call SLIMbus value
element apis, and this could would get messy once we want to add i2c
interface to it.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/base/regmap/Kconfig          |  4 ++
 drivers/base/regmap/Makefile         |  1 +
 drivers/base/regmap/regmap-slimbus.c | 89 ++++++++++++++++++++++++++++++++++++
 include/linux/regmap.h               | 18 ++++++++
 4 files changed, 112 insertions(+)
 create mode 100644 drivers/base/regmap/regmap-slimbus.c

diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig
index 3a1535d812d8..cc162b48c6d7 100644
--- a/drivers/base/regmap/Kconfig
+++ b/drivers/base/regmap/Kconfig
@@ -21,6 +21,10 @@ config REGMAP_I2C
 	tristate
 	depends on I2C
 
+config REGMAP_SLIMBUS
+	tristate
+	depends on SLIMBUS
+
 config REGMAP_SPI
 	tristate
 	depends on SPI
diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index 0d298c446108..63dec9222892 100644
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_REGCACHE_COMPRESSED) += regcache-lzo.o
 obj-$(CONFIG_DEBUG_FS) += regmap-debugfs.o
 obj-$(CONFIG_REGMAP_AC97) += regmap-ac97.o
 obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
+obj-$(CONFIG_REGMAP_SLIMBUS) += regmap-slimbus.o
 obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o
 obj-$(CONFIG_REGMAP_SPMI) += regmap-spmi.o
 obj-$(CONFIG_REGMAP_MMIO) += regmap-mmio.o
diff --git a/drivers/base/regmap/regmap-slimbus.c b/drivers/base/regmap/regmap-slimbus.c
new file mode 100644
index 000000000000..d0dab1c5b663
--- /dev/null
+++ b/drivers/base/regmap/regmap-slimbus.c
@@ -0,0 +1,89 @@
+/*
+ * Register map access API - SLIMbus support
+ *
+ * Copyright 2017 Linaro Inc
+ *
+ * Author: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/regmap.h>
+#include <linux/slimbus.h>
+#include <linux/module.h>
+
+#include "internal.h"
+
+static int regmap_slimbus_byte_reg_read(void *context, unsigned int reg,
+					unsigned int *val)
+{
+	struct slim_device *sdev = context;
+	int v;
+
+	v = slim_readb(sdev, reg);
+
+	if (v < 0)
+		return v;
+
+	*val = v;
+
+	return 0;
+}
+
+static int regmap_slimbus_byte_reg_write(void *context, unsigned int reg,
+					 unsigned int val)
+{
+	struct slim_device *sdev = context;
+
+	return slim_writeb(sdev, reg, val);
+}
+
+static struct regmap_bus regmap_slimbus_bus = {
+	.reg_write = regmap_slimbus_byte_reg_write,
+	.reg_read = regmap_slimbus_byte_reg_read,
+	.reg_format_endian_default = REGMAP_ENDIAN_LITTLE,
+	.val_format_endian_default = REGMAP_ENDIAN_LITTLE,
+};
+
+static const struct regmap_bus *regmap_get_slimbus(struct slim_device *slim,
+					const struct regmap_config *config)
+{
+	if (config->val_bits == 8 && config->reg_bits == 8)
+		return &regmap_slimbus_bus;
+
+	return ERR_PTR(-ENOTSUPP);
+}
+
+struct regmap *__regmap_init_slimbus(struct slim_device *slimbus,
+				     const struct regmap_config *config,
+				     struct lock_class_key *lock_key,
+				     const char *lock_name)
+{
+	const struct regmap_bus *bus = regmap_get_slimbus(slimbus, config);
+
+	if (IS_ERR(bus))
+		return ERR_CAST(bus);
+
+	return __regmap_init(&slimbus->dev, bus, &slimbus->dev, config,
+			     lock_key, lock_name);
+}
+EXPORT_SYMBOL_GPL(__regmap_init_slimbus);
+
+struct regmap *__devm_regmap_init_slimbus(struct slim_device *slimbus,
+					  const struct regmap_config *config,
+					  struct lock_class_key *lock_key,
+					  const char *lock_name)
+{
+	const struct regmap_bus *bus = regmap_get_slimbus(slimbus, config);
+
+	if (IS_ERR(bus))
+		return ERR_CAST(bus);
+
+	return __devm_regmap_init(&slimbus->dev, bus, &slimbus, config,
+				  lock_key, lock_name);
+}
+EXPORT_SYMBOL_GPL(__devm_regmap_init_slimbus);
+
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 15eddc1353ba..b2207737a159 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -24,6 +24,7 @@ struct module;
 struct device;
 struct i2c_client;
 struct irq_domain;
+struct slim_device;
 struct spi_device;
 struct spmi_device;
 struct regmap;
@@ -499,6 +500,10 @@ struct regmap *__regmap_init_i2c(struct i2c_client *i2c,
 				 const struct regmap_config *config,
 				 struct lock_class_key *lock_key,
 				 const char *lock_name);
+struct regmap *__regmap_init_slimbus(struct slim_device *slimbus,
+				 const struct regmap_config *config,
+				 struct lock_class_key *lock_key,
+				 const char *lock_name);
 struct regmap *__regmap_init_spi(struct spi_device *dev,
 				 const struct regmap_config *config,
 				 struct lock_class_key *lock_key,
@@ -615,6 +620,19 @@ int regmap_attach_dev(struct device *dev, struct regmap *map,
 	__regmap_lockdep_wrapper(__regmap_init_i2c, #config,		\
 				i2c, config)
 
+/**
+ * regmap_init_slimbus() - Initialise register map
+ *
+ * @slimbus: Device that will be interacted with
+ * @config: Configuration for register map
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer to
+ * a struct regmap.
+ */
+#define regmap_init_slimbus(slimbus, config)				\
+	__regmap_lockdep_wrapper(__regmap_init_slimbus, #config,	\
+				slimbus, config)
+
 /**
  * regmap_init_spi() - Initialise register map
  *
-- 
2.15.0

[PATCH v8 09/13] slimbus: core: add common defines required for controllers

[srinivas.kandagatla]

From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

This patch adds some common constant defines which are required
for qcom slim controller driver.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/slimbus/slimbus.h | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/slimbus/slimbus.h b/drivers/slimbus/slimbus.h
index e0ae7bb1ba47..d278c951ddbf 100644
--- a/drivers/slimbus/slimbus.h
+++ b/drivers/slimbus/slimbus.h
@@ -18,9 +18,38 @@
 #include <linux/completion.h>
 #include <linux/slimbus.h>
 
+/* Standard values per SLIMbus spec needed by controllers and devices */
+#define SLIM_CL_PER_SUPERFRAME		6144
+#define SLIM_CL_PER_SUPERFRAME_DIV8	(SLIM_CL_PER_SUPERFRAME >> 3)
+
 /* SLIMbus message types. Related to interpretation of message code. */
 #define SLIM_MSG_MT_CORE			0x0
 
+/*
+ * SLIM Broadcast header format
+ * BYTE 0: MT[7:5] RL[4:0]
+ * BYTE 1: RSVD[7] MC[6:0]
+ * BYTE 2: RSVD[7:6] DT[5:4] PI[3:0]
+ */
+#define SLIM_MSG_MT_MASK	GENMASK(2, 0)
+#define SLIM_MSG_MT_SHIFT	5
+#define SLIM_MSG_RL_MASK	GENMASK(4, 0)
+#define SLIM_MSG_RL_SHIFT	0
+#define SLIM_MSG_MC_MASK	GENMASK(6, 0)
+#define SLIM_MSG_MC_SHIFT	0
+#define SLIM_MSG_DT_MASK	GENMASK(1, 0)
+#define SLIM_MSG_DT_SHIFT	4
+
+#define SLIM_HEADER_GET_MT(b)	((b >> SLIM_MSG_MT_SHIFT) & SLIM_MSG_MT_MASK)
+#define SLIM_HEADER_GET_RL(b)	((b >> SLIM_MSG_RL_SHIFT) & SLIM_MSG_RL_MASK)
+#define SLIM_HEADER_GET_MC(b)	((b >> SLIM_MSG_MC_SHIFT) & SLIM_MSG_MC_MASK)
+#define SLIM_HEADER_GET_DT(b)	((b >> SLIM_MSG_DT_SHIFT) & SLIM_MSG_DT_MASK)
+
+/* Device management messages used by this framework */
+#define SLIM_MSG_MC_REPORT_PRESENT               0x1
+#define SLIM_MSG_MC_ASSIGN_LOGICAL_ADDRESS       0x2
+#define SLIM_MSG_MC_REPORT_ABSENT                0xF
+
 /* Clock pause Reconfiguration messages */
 #define SLIM_MSG_MC_BEGIN_RECONFIGURATION        0x40
 #define SLIM_MSG_MC_NEXT_PAUSE_CLOCK             0x4A
@@ -101,6 +130,10 @@ struct slim_msg_txn {
 #define DEFINE_SLIM_BCAST_TXN(name, mc, rl, la, msg) \
 	struct slim_msg_txn name = { rl, 0, mc, SLIM_MSG_DEST_BROADCAST, 0,\
 					0, la, msg, }
+
+#define DEFINE_SLIM_EDEST_TXN(name, mc, rl, la, msg) \
+	struct slim_msg_txn name = { rl, 0, mc, SLIM_MSG_DEST_ENUMADDR, 0,\
+					0, la, msg, }
 /**
  * enum slim_clk_state: SLIMbus controller's clock state used internally for
  *	maintaining current clock state.
-- 
2.15.0

[PATCH v8 10/13] dt-bindings: Add qcom slimbus controller bindings

[srinivas.kandagatla]

From: Sagar Dharia <sdharia@codeaurora.org>

This patch add device tree bindings for Qualcomm slimbus controller.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 .../devicetree/bindings/slimbus/slim-qcom-ctrl.txt | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/slimbus/slim-qcom-ctrl.txt

diff --git a/Documentation/devicetree/bindings/slimbus/slim-qcom-ctrl.txt b/Documentation/devicetree/bindings/slimbus/slim-qcom-ctrl.txt
new file mode 100644
index 000000000000..93a6fdaf09b3
--- /dev/null
+++ b/Documentation/devicetree/bindings/slimbus/slim-qcom-ctrl.txt
@@ -0,0 +1,39 @@
+Qualcomm SLIMbus controller
+This controller is used if applications processor driver controls SLIMbus
+master component.
+
+Required properties:
+
+ - #address-cells - refer to Documentation/devicetree/bindings/slimbus/bus.txt
+ - #size-cells	- refer to Documentation/devicetree/bindings/slimbus/bus.txt
+
+ - reg : Offset and length of the register region(s) for the device
+ - reg-names : Register region name(s) referenced in reg above
+	 Required register resource entries are:
+	 "ctrl": Physical address of controller register blocks
+ 	 "slew": required for "qcom,apq8064-slim" SOC.
+ - compatible : should be "qcom,<SOC-NAME>-slim" for SOC specific compatible
+ 		followed by "qcom,slim" for fallback.
+ - interrupts : Interrupt number used by this controller
+ - clocks : Interface and core clocks used by this SLIMbus controller
+ - clock-names : Required clock-name entries are:
+	"iface_clk" : Interface clock for this controller
+	"core_clk" : Interrupt for controller core's BAM
+
+Example:
+
+	slim@28080000 {
+		compatible = "qcom,apq8064-slim", "qcom,slim";
+		reg = <0x28080000 0x2000>, <0x80207C 4>;
+		reg-names = "ctrl", "slew";
+		interrupts = <0 33 0>;
+		clocks = <&lcc SLIMBUS_SRC>, <&lcc AUDIO_SLIMBUS_CLK>;
+		clock-names = "iface", "core";
+		#address-cells = <2>;
+		#size-cell = <0>;
+
+		wcd9310: audio-codec@1,0{
+			compatible = "slim217,60";
+			reg = <1 0>;
+		};
+	};
-- 
2.15.0

[PATCH v8 11/13] slimbus: qcom: Add Qualcomm Slimbus controller driver

[srinivas.kandagatla]

From: Sagar Dharia <sdharia@codeaurora.org>

This controller driver programs manager, interface, and framer
devices for Qualcomm's slimbus HW block.
Manager component currently implements logical address setting,
and messaging interface.
Interface device reports bus synchronization information, and framer
device clocks the bus from the time it's woken up, until clock-pause
is executed by the manager device.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/slimbus/Kconfig     |   6 +
 drivers/slimbus/Makefile    |   4 +
 drivers/slimbus/qcom-ctrl.c | 661 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 671 insertions(+)
 create mode 100644 drivers/slimbus/qcom-ctrl.c

diff --git a/drivers/slimbus/Kconfig b/drivers/slimbus/Kconfig
index ecf94ef66f10..deac30b020fe 100644
--- a/drivers/slimbus/Kconfig
+++ b/drivers/slimbus/Kconfig
@@ -12,5 +12,11 @@ menuconfig SLIMBUS
 if SLIMBUS
 
 # SLIMbus controllers
+config SLIM_QCOM_CTRL
+	tristate "Qualcomm SLIMbus Manager Component"
+	depends on SLIMBUS
+	help
+	  Select driver if Qualcomm's SLIMbus Manager Component is
+	  programmed using Linux kernel.
 
 endif
diff --git a/drivers/slimbus/Makefile b/drivers/slimbus/Makefile
index fd794f83d1cf..b3830de1edca 100644
--- a/drivers/slimbus/Makefile
+++ b/drivers/slimbus/Makefile
@@ -3,3 +3,7 @@
 #
 obj-$(CONFIG_SLIMBUS)			+= slimbus.o
 slimbus-y				:= core.o messaging.o sched.o
+
+#Controllers
+obj-$(CONFIG_SLIM_QCOM_CTRL)		+= slim-qcom-ctrl.o
+slim-qcom-ctrl-y			:= qcom-ctrl.o
diff --git a/drivers/slimbus/qcom-ctrl.c b/drivers/slimbus/qcom-ctrl.c
new file mode 100644
index 000000000000..af7b109e3d28
--- /dev/null
+++ b/drivers/slimbus/qcom-ctrl.c
@@ -0,0 +1,661 @@
+/* Copyright (c) 2011-2017, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <linux/dma-mapping.h>
+#include "slimbus.h"
+
+/* Manager registers */
+#define	MGR_CFG		0x200
+#define	MGR_STATUS	0x204
+#define	MGR_INT_EN	0x210
+#define	MGR_INT_STAT	0x214
+#define	MGR_INT_CLR	0x218
+#define	MGR_TX_MSG	0x230
+#define	MGR_RX_MSG	0x270
+#define	MGR_IE_STAT	0x2F0
+#define	MGR_VE_STAT	0x300
+#define	MGR_CFG_ENABLE	1
+
+/* Framer registers */
+#define	FRM_CFG		0x400
+#define	FRM_STAT	0x404
+#define	FRM_INT_EN	0x410
+#define	FRM_INT_STAT	0x414
+#define	FRM_INT_CLR	0x418
+#define	FRM_WAKEUP	0x41C
+#define	FRM_CLKCTL_DONE	0x420
+#define	FRM_IE_STAT	0x430
+#define	FRM_VE_STAT	0x440
+
+/* Interface registers */
+#define	INTF_CFG	0x600
+#define	INTF_STAT	0x604
+#define	INTF_INT_EN	0x610
+#define	INTF_INT_STAT	0x614
+#define	INTF_INT_CLR	0x618
+#define	INTF_IE_STAT	0x630
+#define	INTF_VE_STAT	0x640
+
+/* Interrupt status bits */
+#define	MGR_INT_TX_NACKED_2	BIT(25)
+#define	MGR_INT_MSG_BUF_CONTE	BIT(26)
+#define	MGR_INT_RX_MSG_RCVD	BIT(30)
+#define	MGR_INT_TX_MSG_SENT	BIT(31)
+
+/* Framer config register settings */
+#define	FRM_ACTIVE	1
+#define	CLK_GEAR	7
+#define	ROOT_FREQ	11
+#define	REF_CLK_GEAR	15
+#define	INTR_WAKE	19
+
+#define SLIM_MSG_ASM_FIRST_WORD(l, mt, mc, dt, ad) \
+		((l) | ((mt) << 5) | ((mc) << 8) | ((dt) << 15) | ((ad) << 16))
+
+#define SLIM_ROOT_FREQ 24576000
+
+/* MAX message size over control channel */
+#define SLIM_MSGQ_BUF_LEN	40
+#define QCOM_TX_MSGS 2
+#define QCOM_RX_MSGS	8
+#define QCOM_BUF_ALLOC_RETRIES	10
+
+#define CFG_PORT(r, v) ((v) ? CFG_PORT_V2(r) : CFG_PORT_V1(r))
+
+/* V2 Component registers */
+#define CFG_PORT_V2(r) ((r ## _V2))
+#define	COMP_CFG_V2		4
+#define	COMP_TRUST_CFG_V2	0x3000
+
+/* V1 Component registers */
+#define CFG_PORT_V1(r) ((r ## _V1))
+#define	COMP_CFG_V1		0
+#define	COMP_TRUST_CFG_V1	0x14
+
+/* Resource group info for manager, and non-ported generic device-components */
+#define EE_MGR_RSC_GRP	(1 << 10)
+#define EE_NGD_2	(2 << 6)
+#define EE_NGD_1	0
+
+struct slim_ctrl_buf {
+	void		*base;
+	phys_addr_t	phy;
+	spinlock_t	lock;
+	int		head;
+	int		tail;
+	int		sl_sz;
+	int		n;
+};
+
+struct qcom_slim_ctrl {
+	struct slim_controller  ctrl;
+	struct slim_framer	framer;
+	struct device		*dev;
+	void __iomem		*base;
+	void __iomem		*slew_reg;
+
+	struct slim_ctrl_buf	rx;
+	struct slim_ctrl_buf	tx;
+
+	struct completion	**wr_comp;
+	int			irq;
+	struct workqueue_struct *rxwq;
+	struct work_struct	wd;
+	struct clk		*rclk;
+	struct clk		*hclk;
+};
+
+static void qcom_slim_queue_tx(struct qcom_slim_ctrl *ctrl, void *buf,
+			       u8 len, u32 tx_reg)
+{
+	int count = (len + 3) >> 2;
+
+	__iowrite32_copy(ctrl->base + tx_reg, buf, count);
+
+	/* Ensure Oder of subsequent writes */
+	mb();
+}
+
+static void *slim_alloc_rxbuf(struct qcom_slim_ctrl *ctrl)
+{
+	unsigned long flags;
+	int idx;
+
+	spin_lock_irqsave(&ctrl->rx.lock, flags);
+	if ((ctrl->rx.tail + 1) % ctrl->rx.n == ctrl->rx.head) {
+		spin_unlock_irqrestore(&ctrl->rx.lock, flags);
+		dev_err(ctrl->dev, "RX QUEUE full!");
+		return NULL;
+	}
+	idx = ctrl->rx.tail;
+	ctrl->rx.tail = (ctrl->rx.tail + 1) % ctrl->rx.n;
+	spin_unlock_irqrestore(&ctrl->rx.lock, flags);
+
+	return ctrl->rx.base + (idx * ctrl->rx.sl_sz);
+}
+
+void slim_ack_txn(struct qcom_slim_ctrl *ctrl, int err)
+{
+	struct completion *comp;
+	unsigned long flags;
+	int idx;
+
+	spin_lock_irqsave(&ctrl->tx.lock, flags);
+	idx = ctrl->tx.head;
+	ctrl->tx.head = (ctrl->tx.head + 1) % ctrl->tx.n;
+	spin_unlock_irqrestore(&ctrl->tx.lock, flags);
+
+	comp = ctrl->wr_comp[idx];
+	ctrl->wr_comp[idx] = NULL;
+
+	complete(comp);
+}
+
+static irqreturn_t qcom_slim_handle_tx_irq(struct qcom_slim_ctrl *ctrl,
+					   u32 stat)
+{
+	int err = 0;
+
+	if (stat & MGR_INT_TX_MSG_SENT)
+		writel_relaxed(MGR_INT_TX_MSG_SENT,
+			       ctrl->base + MGR_INT_CLR);
+
+	if (stat & MGR_INT_TX_NACKED_2) {
+		u32 mgr_stat = readl_relaxed(ctrl->base + MGR_STATUS);
+		u32 mgr_ie_stat = readl_relaxed(ctrl->base + MGR_IE_STAT);
+		u32 frm_stat = readl_relaxed(ctrl->base + FRM_STAT);
+		u32 frm_cfg = readl_relaxed(ctrl->base + FRM_CFG);
+		u32 frm_intr_stat = readl_relaxed(ctrl->base + FRM_INT_STAT);
+		u32 frm_ie_stat = readl_relaxed(ctrl->base + FRM_IE_STAT);
+		u32 intf_stat = readl_relaxed(ctrl->base + INTF_STAT);
+		u32 intf_intr_stat = readl_relaxed(ctrl->base + INTF_INT_STAT);
+		u32 intf_ie_stat = readl_relaxed(ctrl->base + INTF_IE_STAT);
+
+		writel_relaxed(MGR_INT_TX_NACKED_2, ctrl->base + MGR_INT_CLR);
+
+		dev_err(ctrl->dev, "TX Nack MGR:int:0x%x, stat:0x%x\n",
+			stat, mgr_stat);
+		dev_err(ctrl->dev, "TX Nack MGR:ie:0x%x\n", mgr_ie_stat);
+		dev_err(ctrl->dev, "TX Nack FRM:int:0x%x, stat:0x%x\n",
+			frm_intr_stat, frm_stat);
+		dev_err(ctrl->dev, "TX Nack FRM:cfg:0x%x, ie:0x%x\n",
+			frm_cfg, frm_ie_stat);
+		dev_err(ctrl->dev, "TX Nack INTF:intr:0x%x, stat:0x%x\n",
+			intf_intr_stat, intf_stat);
+		dev_err(ctrl->dev, "TX Nack INTF:ie:0x%x\n",
+			intf_ie_stat);
+		err = -ENOTCONN;
+	}
+
+	slim_ack_txn(ctrl, err);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t qcom_slim_handle_rx_irq(struct qcom_slim_ctrl *ctrl,
+					   u32 stat)
+{
+	u32 *rx_buf, pkt[10];
+	bool q_rx = false;
+	u8 mc, mt, len;
+
+	pkt[0] = readl_relaxed(ctrl->base + MGR_RX_MSG);
+	mt = SLIM_HEADER_GET_MT(pkt[0]);
+	len = SLIM_HEADER_GET_RL(pkt[0]);
+	mc = SLIM_HEADER_GET_MC(pkt[0]>>8);
+
+	/*
+	 * this message cannot be handled by ISR, so
+	 * let work-queue handle it
+	 */
+	if (mt == SLIM_MSG_MT_CORE && mc == SLIM_MSG_MC_REPORT_PRESENT) {
+		rx_buf = (u32 *)slim_alloc_rxbuf(ctrl);
+		if (!rx_buf) {
+			dev_err(ctrl->dev, "dropping RX:0x%x due to RX full\n",
+					pkt[0]);
+			goto rx_ret_irq;
+		}
+		rx_buf[0] = pkt[0];
+
+	} else {
+		rx_buf = pkt;
+	}
+
+	__ioread32_copy(rx_buf + 1, ctrl->base + MGR_RX_MSG + 4,
+			DIV_ROUND_UP(len, 4));
+
+	switch (mc) {
+
+	case SLIM_MSG_MC_REPORT_PRESENT:
+		q_rx = true;
+		break;
+	case SLIM_MSG_MC_REPLY_INFORMATION:
+	case SLIM_MSG_MC_REPLY_VALUE:
+		slim_msg_response(&ctrl->ctrl, (u8 *)(rx_buf + 1),
+				  (u8)(*rx_buf >> 24), (len - 4));
+		break;
+	default:
+		dev_err(ctrl->dev, "unsupported MC,%x MT:%x\n",
+			mc, mt);
+		break;
+	}
+rx_ret_irq:
+	writel(MGR_INT_RX_MSG_RCVD, ctrl->base +
+		       MGR_INT_CLR);
+	if (q_rx)
+		queue_work(ctrl->rxwq, &ctrl->wd);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t qcom_slim_interrupt(int irq, void *d)
+{
+	struct qcom_slim_ctrl *ctrl = d;
+	u32 stat = readl_relaxed(ctrl->base + MGR_INT_STAT);
+	int ret = IRQ_NONE;
+
+	if (stat & MGR_INT_TX_MSG_SENT || stat & MGR_INT_TX_NACKED_2)
+		ret = qcom_slim_handle_tx_irq(ctrl, stat);
+
+	if (stat & MGR_INT_RX_MSG_RCVD)
+		ret = qcom_slim_handle_rx_irq(ctrl, stat);
+
+	return ret;
+}
+
+void *slim_alloc_txbuf(struct qcom_slim_ctrl *ctrl, struct slim_msg_txn *txn,
+		       struct completion *done)
+{
+	unsigned long flags;
+	int idx;
+
+	spin_lock_irqsave(&ctrl->tx.lock, flags);
+	if (((ctrl->tx.head + 1) % ctrl->tx.n) == ctrl->tx.tail) {
+		spin_unlock_irqrestore(&ctrl->tx.lock, flags);
+		dev_err(ctrl->dev, "controller TX buf unavailable");
+		return NULL;
+	}
+	idx = ctrl->tx.tail;
+	ctrl->wr_comp[idx] = done;
+	ctrl->tx.tail = (ctrl->tx.tail + 1) % ctrl->tx.n;
+
+	spin_unlock_irqrestore(&ctrl->tx.lock, flags);
+
+	return ctrl->tx.base + (idx * ctrl->tx.sl_sz);
+}
+
+
+static int qcom_xfer_msg(struct slim_controller *sctrl,
+			 struct slim_msg_txn *txn)
+{
+	struct qcom_slim_ctrl *ctrl = dev_get_drvdata(sctrl->dev);
+	DECLARE_COMPLETION_ONSTACK(done);
+	void *pbuf = slim_alloc_txbuf(ctrl, txn, &done);
+	unsigned long ms = txn->rl + HZ;
+	u8 *puc;
+	int ret = 0, timeout, retries = QCOM_BUF_ALLOC_RETRIES;
+	u8 la = txn->la;
+	u32 *head;
+	/* HW expects length field to be excluded */
+	txn->rl--;
+
+	/* spin till buffer is made available */
+	if (!pbuf) {
+		while (retries--) {
+			usleep_range(10000, 15000);
+			pbuf = slim_alloc_txbuf(ctrl, txn, &done);
+			if (pbuf)
+				break;
+		}
+	}
+
+	if (!retries && !pbuf)
+		return -ENOMEM;
+
+	puc = (u8 *)pbuf;
+	head = (u32 *)pbuf;
+
+	if (txn->dt == SLIM_MSG_DEST_LOGICALADDR) {
+		*head = SLIM_MSG_ASM_FIRST_WORD(txn->rl, txn->mt,
+						txn->mc, 0, la);
+		puc += 3;
+	} else {
+		*head = SLIM_MSG_ASM_FIRST_WORD(txn->rl, txn->mt,
+						txn->mc, 1, la);
+		puc += 2;
+	}
+
+	if (slim_tid_txn(txn->mt, txn->mc))
+		*(puc++) = txn->tid;
+
+	if (slim_ec_txn(txn->mt, txn->mc)) {
+		*(puc++) = (txn->ec & 0xFF);
+		*(puc++) = (txn->ec >> 8) & 0xFF;
+	}
+
+	if (txn->msg && txn->msg->wbuf)
+		memcpy(puc, txn->msg->wbuf, txn->msg->num_bytes);
+
+	qcom_slim_queue_tx(ctrl, head, txn->rl, MGR_TX_MSG);
+	timeout = wait_for_completion_timeout(&done, msecs_to_jiffies(ms));
+
+	if (!timeout) {
+		dev_err(ctrl->dev, "TX timed out:MC:0x%x,mt:0x%x", txn->mc,
+					txn->mt);
+		ret = -ETIMEDOUT;
+	}
+
+	return ret;
+
+}
+
+static int qcom_set_laddr(struct slim_controller *sctrl,
+				struct slim_eaddr *ead, u8 laddr)
+{
+	struct qcom_slim_ctrl *ctrl = dev_get_drvdata(sctrl->dev);
+	struct {
+		__be16 manf_id;
+		__be16 prod_code;
+		u8 dev_index;
+		u8 instance;
+		u8 laddr;
+	} __packed p;
+	struct slim_val_inf msg = {0};
+	DEFINE_SLIM_EDEST_TXN(txn, SLIM_MSG_MC_ASSIGN_LOGICAL_ADDRESS,
+			      10, laddr, &msg);
+	int ret;
+
+	p.manf_id = cpu_to_be16(ead->manf_id);
+	p.prod_code = cpu_to_be16(ead->prod_code);
+	p.dev_index = ead->dev_index;
+	p.instance = ead->instance;
+	p.laddr = laddr;
+
+	msg.wbuf = (void *)&p;
+	msg.num_bytes = 7;
+	ret = slim_do_transfer(&ctrl->ctrl, &txn);
+
+	if (ret)
+		dev_err(ctrl->dev, "set LA:0x%x failed:ret:%d\n",
+				  laddr, ret);
+	return ret;
+}
+
+static int slim_get_current_rxbuf(struct qcom_slim_ctrl *ctrl, void *buf)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&ctrl->rx.lock, flags);
+	if (ctrl->rx.tail == ctrl->rx.head) {
+		spin_unlock_irqrestore(&ctrl->rx.lock, flags);
+		return -ENODATA;
+	}
+	memcpy(buf, ctrl->rx.base + (ctrl->rx.head * ctrl->rx.sl_sz),
+				ctrl->rx.sl_sz);
+
+	ctrl->rx.head = (ctrl->rx.head + 1) % ctrl->rx.n;
+	spin_unlock_irqrestore(&ctrl->rx.lock, flags);
+
+	return 0;
+}
+
+static void qcom_slim_rxwq(struct work_struct *work)
+{
+	u8 buf[SLIM_MSGQ_BUF_LEN];
+	u8 mc, mt, len;
+	int ret;
+	struct qcom_slim_ctrl *ctrl = container_of(work, struct qcom_slim_ctrl,
+						 wd);
+
+	while ((slim_get_current_rxbuf(ctrl, buf)) != -ENODATA) {
+		len = SLIM_HEADER_GET_RL(buf[0]);
+		mt = SLIM_HEADER_GET_MT(buf[0]);
+		mc = SLIM_HEADER_GET_MC(buf[1]);
+		if (mt == SLIM_MSG_MT_CORE &&
+			mc == SLIM_MSG_MC_REPORT_PRESENT) {
+			struct slim_eaddr ea;
+			u8 laddr;
+
+			ea.manf_id = be16_to_cpup((__be16 *)&buf[2]);
+			ea.prod_code = be16_to_cpup((__be16 *)&buf[4]);
+			ea.dev_index = buf[6];
+			ea.instance = buf[7];
+
+			ret = slim_device_report_present(&ctrl->ctrl, &ea,
+							 &laddr);
+			if (ret < 0)
+				dev_err(ctrl->dev, "assign laddr failed:%d\n",
+					ret);
+		} else {
+			dev_err(ctrl->dev, "unexpected message:mc:%x, mt:%x\n",
+				mc, mt);
+		}
+	}
+}
+
+static void qcom_slim_prg_slew(struct platform_device *pdev,
+				struct qcom_slim_ctrl *ctrl)
+{
+	struct resource	*slew_mem;
+
+	if (!ctrl->slew_reg) {
+		/* SLEW RATE register for this SLIMbus */
+		slew_mem = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+				"slew");
+		ctrl->slew_reg = devm_ioremap(&pdev->dev, slew_mem->start,
+				resource_size(slew_mem));
+		if (!ctrl->slew_reg)
+			return;
+	}
+
+	writel_relaxed(1, ctrl->slew_reg);
+	/* Make sure SLIMbus-slew rate enabling goes through */
+	wmb();
+}
+
+static int qcom_slim_probe(struct platform_device *pdev)
+{
+	struct qcom_slim_ctrl *ctrl;
+	struct slim_controller *sctrl;
+	struct resource *slim_mem;
+	int ret, ver;
+
+	ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
+	if (!ctrl)
+		return -ENOMEM;
+
+	ctrl->hclk = devm_clk_get(&pdev->dev, "iface");
+	if (IS_ERR(ctrl->hclk))
+		return PTR_ERR(ctrl->hclk);
+
+	ctrl->rclk = devm_clk_get(&pdev->dev, "core");
+	if (IS_ERR(ctrl->rclk))
+		return PTR_ERR(ctrl->rclk);
+
+	ret = clk_set_rate(ctrl->rclk, SLIM_ROOT_FREQ);
+	if (ret) {
+		dev_err(&pdev->dev, "ref-clock set-rate failed:%d\n", ret);
+		return ret;
+	}
+
+	ctrl->irq = platform_get_irq(pdev, 0);
+	if (!ctrl->irq) {
+		dev_err(&pdev->dev, "no slimbus IRQ\n");
+		return -ENODEV;
+	}
+
+	sctrl = &ctrl->ctrl;
+	sctrl->dev = &pdev->dev;
+	ctrl->dev = &pdev->dev;
+	platform_set_drvdata(pdev, ctrl);
+	dev_set_drvdata(ctrl->dev, ctrl);
+
+	slim_mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ctrl");
+	ctrl->base = devm_ioremap_resource(ctrl->dev, slim_mem);
+	if (!ctrl->base) {
+		dev_err(&pdev->dev, "IOremap failed\n");
+		return -ENOMEM;
+	}
+
+	sctrl->set_laddr = qcom_set_laddr;
+	sctrl->xfer_msg = qcom_xfer_msg;
+	ctrl->tx.n = QCOM_TX_MSGS;
+	ctrl->tx.sl_sz = SLIM_MSGQ_BUF_LEN;
+	ctrl->rx.n = QCOM_RX_MSGS;
+	ctrl->rx.sl_sz = SLIM_MSGQ_BUF_LEN;
+	ctrl->wr_comp = kzalloc(sizeof(struct completion *) * QCOM_TX_MSGS,
+				GFP_KERNEL);
+	if (!ctrl->wr_comp)
+		return -ENOMEM;
+
+	spin_lock_init(&ctrl->rx.lock);
+	spin_lock_init(&ctrl->tx.lock);
+	INIT_WORK(&ctrl->wd, qcom_slim_rxwq);
+	ctrl->rxwq = create_singlethread_workqueue("qcom_slim_rx");
+	if (!ctrl->rxwq) {
+		dev_err(ctrl->dev, "Failed to start Rx WQ\n");
+		return -ENOMEM;
+	}
+
+	ctrl->framer.rootfreq = SLIM_ROOT_FREQ / 8;
+	ctrl->framer.superfreq =
+		ctrl->framer.rootfreq / SLIM_CL_PER_SUPERFRAME_DIV8;
+	sctrl->a_framer = &ctrl->framer;
+	sctrl->clkgear = SLIM_MAX_CLK_GEAR;
+
+	qcom_slim_prg_slew(pdev, ctrl);
+
+	ret = devm_request_irq(&pdev->dev, ctrl->irq, qcom_slim_interrupt,
+				IRQF_TRIGGER_HIGH, "qcom_slim_irq", ctrl);
+	if (ret) {
+		dev_err(&pdev->dev, "request IRQ failed\n");
+		goto err_request_irq_failed;
+	}
+
+	ret = clk_prepare_enable(ctrl->hclk);
+	if (ret)
+		goto err_hclk_enable_failed;
+
+	ret = clk_prepare_enable(ctrl->rclk);
+	if (ret)
+		goto err_rclk_enable_failed;
+
+	ctrl->tx.base = dmam_alloc_coherent(&pdev->dev,
+					   (ctrl->tx.sl_sz * ctrl->tx.n),
+					   &ctrl->tx.phy, GFP_KERNEL);
+	if (!ctrl->tx.base) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ctrl->rx.base = dmam_alloc_coherent(&pdev->dev,
+					   (ctrl->rx.sl_sz * ctrl->rx.n),
+					   &ctrl->rx.phy, GFP_KERNEL);
+	if (!ctrl->rx.base) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	/* Register with framework before enabling frame, clock */
+	ret = slim_register_controller(&ctrl->ctrl);
+	if (ret) {
+		dev_err(ctrl->dev, "error adding controller\n");
+		goto err;
+	}
+
+	ver = readl_relaxed(ctrl->base);
+	/* Version info in 16 MSbits */
+	ver >>= 16;
+	/* Component register initialization */
+	writel(1, ctrl->base + CFG_PORT(COMP_CFG, ver));
+	writel((EE_MGR_RSC_GRP | EE_NGD_2 | EE_NGD_1),
+				ctrl->base + CFG_PORT(COMP_TRUST_CFG, ver));
+
+	writel((MGR_INT_TX_NACKED_2 |
+			MGR_INT_MSG_BUF_CONTE | MGR_INT_RX_MSG_RCVD |
+			MGR_INT_TX_MSG_SENT), ctrl->base + MGR_INT_EN);
+	writel(1, ctrl->base + MGR_CFG);
+	/* Framer register initialization */
+	writel((1 << INTR_WAKE) | (0xA << REF_CLK_GEAR) |
+		(0xA << CLK_GEAR) | (1 << ROOT_FREQ) | (1 << FRM_ACTIVE) | 1,
+		ctrl->base + FRM_CFG);
+	writel(MGR_CFG_ENABLE, ctrl->base + MGR_CFG);
+	writel(1, ctrl->base + INTF_CFG);
+	writel(1, ctrl->base + CFG_PORT(COMP_CFG, ver));
+
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, QCOM_SLIM_AUTOSUSPEND);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	dev_dbg(ctrl->dev, "QCOM SB controller is up:ver:0x%x!\n", ver);
+	return 0;
+
+err:
+	clk_disable_unprepare(ctrl->rclk);
+err_rclk_enable_failed:
+	clk_disable_unprepare(ctrl->hclk);
+err_hclk_enable_failed:
+err_request_irq_failed:
+	destroy_workqueue(ctrl->rxwq);
+	return ret;
+}
+
+static int qcom_slim_remove(struct platform_device *pdev)
+{
+	struct qcom_slim_ctrl *ctrl = platform_get_drvdata(pdev);
+
+	disable_irq(ctrl->irq);
+	clk_disable_unprepare(ctrl->hclk);
+	clk_disable_unprepare(ctrl->rclk);
+	slim_unregister_controller(&ctrl->ctrl);
+	destroy_workqueue(ctrl->rxwq);
+	return 0;
+}
+
+static const struct dev_pm_ops qcom_slim_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(qcom_slim_suspend, qcom_slim_resume)
+	SET_RUNTIME_PM_OPS(
+			   qcom_slim_runtime_suspend,
+			   qcom_slim_runtime_resume,
+			   NULL
+	)
+};
+
+static const struct of_device_id qcom_slim_dt_match[] = {
+	{ .compatible = "qcom,slim", },
+	{ .compatible = "qcom,apq8064-slim", },
+	{}
+};
+
+static struct platform_driver qcom_slim_driver = {
+	.probe = qcom_slim_probe,
+	.remove = qcom_slim_remove,
+	.driver	= {
+		.name = "qcom_slim_ctrl",
+		.of_match_table = qcom_slim_dt_match,
+	},
+};
+module_platform_driver(qcom_slim_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Qualcomm SLIMbus Controller");
-- 
2.15.0

[PATCH v8 12/13] slimbus: qcom: Add runtime-pm support using clock-pause

[srinivas.kandagatla]

From: Sagar Dharia <sdharia@codeaurora.org>

Slimbus HW mandates that clock-pause sequence has to be executed
before disabling relevant interface and core clocks.
Runtime-PM's autosuspend feature is used here to enter/exit low
power mode for Qualcomm's Slimbus controller. Autosuspend feature
enables driver to avoid changing power-modes too frequently since
entering clock-pause is an expensive sequence

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/slimbus/qcom-ctrl.c | 101 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 98 insertions(+), 3 deletions(-)

diff --git a/drivers/slimbus/qcom-ctrl.c b/drivers/slimbus/qcom-ctrl.c
index af7b109e3d28..8c05346cd69c 100644
--- a/drivers/slimbus/qcom-ctrl.c
+++ b/drivers/slimbus/qcom-ctrl.c
@@ -20,6 +20,7 @@
 #include <linux/clk.h>
 #include <linux/of.h>
 #include <linux/dma-mapping.h>
+#include <linux/pm_runtime.h>
 #include "slimbus.h"
 
 /* Manager registers */
@@ -71,6 +72,7 @@
 		((l) | ((mt) << 5) | ((mc) << 8) | ((dt) << 15) | ((ad) << 16))
 
 #define SLIM_ROOT_FREQ 24576000
+#define QCOM_SLIM_AUTOSUSPEND 1000
 
 /* MAX message size over control channel */
 #define SLIM_MSGQ_BUF_LEN	40
@@ -281,6 +283,30 @@ static irqreturn_t qcom_slim_interrupt(int irq, void *d)
 	return ret;
 }
 
+static int qcom_clk_pause_wakeup(struct slim_controller *sctrl)
+{
+	struct qcom_slim_ctrl *ctrl = dev_get_drvdata(sctrl->dev);
+
+	clk_prepare_enable(ctrl->hclk);
+	clk_prepare_enable(ctrl->rclk);
+	enable_irq(ctrl->irq);
+
+	writel_relaxed(1, ctrl->base + FRM_WAKEUP);
+	/* Make sure framer wakeup write goes through before ISR fires */
+	mb();
+	/*
+	 * HW Workaround: Currently, slave is reporting lost-sync messages
+	 * after SLIMbus comes out of clock pause.
+	 * Transaction with slave fail before slave reports that message
+	 * Give some time for that report to come
+	 * SLIMbus wakes up in clock gear 10 at 24.576MHz. With each superframe
+	 * being 250 usecs, we wait for 5-10 superframes here to ensure
+	 * we get the message
+	 */
+	usleep_range(1250, 2500);
+	return 0;
+}
+
 void *slim_alloc_txbuf(struct qcom_slim_ctrl *ctrl, struct slim_msg_txn *txn,
 		       struct completion *done)
 {
@@ -517,6 +543,7 @@ static int qcom_slim_probe(struct platform_device *pdev)
 
 	sctrl->set_laddr = qcom_set_laddr;
 	sctrl->xfer_msg = qcom_xfer_msg;
+	sctrl->wakeup =  qcom_clk_pause_wakeup;
 	ctrl->tx.n = QCOM_TX_MSGS;
 	ctrl->tx.sl_sz = SLIM_MSGQ_BUF_LEN;
 	ctrl->rx.n = QCOM_RX_MSGS;
@@ -624,14 +651,81 @@ static int qcom_slim_remove(struct platform_device *pdev)
 {
 	struct qcom_slim_ctrl *ctrl = platform_get_drvdata(pdev);
 
-	disable_irq(ctrl->irq);
-	clk_disable_unprepare(ctrl->hclk);
-	clk_disable_unprepare(ctrl->rclk);
+	pm_runtime_disable(&pdev->dev);
 	slim_unregister_controller(&ctrl->ctrl);
 	destroy_workqueue(ctrl->rxwq);
 	return 0;
 }
 
+/*
+ * If PM_RUNTIME is not defined, these 2 functions become helper
+ * functions to be called from system suspend/resume.
+ */
+#ifdef CONFIG_PM
+static int qcom_slim_runtime_suspend(struct device *device)
+{
+	struct platform_device *pdev = to_platform_device(device);
+	struct qcom_slim_ctrl *ctrl = platform_get_drvdata(pdev);
+	int ret;
+
+	dev_dbg(device, "pm_runtime: suspending...\n");
+	ret = slim_ctrl_clk_pause(&ctrl->ctrl, false, SLIM_CLK_UNSPECIFIED);
+	if (ret) {
+		dev_err(device, "clk pause not entered:%d", ret);
+	} else {
+		disable_irq(ctrl->irq);
+		clk_disable_unprepare(ctrl->hclk);
+		clk_disable_unprepare(ctrl->rclk);
+	}
+	return ret;
+}
+
+static int qcom_slim_runtime_resume(struct device *device)
+{
+	struct platform_device *pdev = to_platform_device(device);
+	struct qcom_slim_ctrl *ctrl = platform_get_drvdata(pdev);
+	int ret = 0;
+
+	dev_dbg(device, "pm_runtime: resuming...\n");
+	ret = slim_ctrl_clk_pause(&ctrl->ctrl, true, 0);
+	if (ret)
+		dev_err(device, "clk pause not exited:%d", ret);
+	return ret;
+}
+#endif
+
+#ifdef CONFIG_PM_SLEEP
+static int qcom_slim_suspend(struct device *dev)
+{
+	int ret = 0;
+
+	if (!pm_runtime_enabled(dev) ||
+		(!pm_runtime_suspended(dev))) {
+		dev_dbg(dev, "system suspend");
+		ret = qcom_slim_runtime_suspend(dev);
+	}
+
+	return ret;
+}
+
+static int qcom_slim_resume(struct device *dev)
+{
+	if (!pm_runtime_enabled(dev) || !pm_runtime_suspended(dev)) {
+		int ret;
+
+		dev_dbg(dev, "system resume");
+		ret = qcom_slim_runtime_resume(dev);
+		if (!ret) {
+			pm_runtime_mark_last_busy(dev);
+			pm_request_autosuspend(dev);
+		}
+		return ret;
+
+	}
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
 static const struct dev_pm_ops qcom_slim_dev_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(qcom_slim_suspend, qcom_slim_resume)
 	SET_RUNTIME_PM_OPS(
@@ -653,6 +747,7 @@ static struct platform_driver qcom_slim_driver = {
 	.driver	= {
 		.name = "qcom_slim_ctrl",
 		.of_match_table = qcom_slim_dt_match,
+		.pm = &qcom_slim_dev_pm_ops,
 	},
 };
 module_platform_driver(qcom_slim_driver);
-- 
2.15.0

[PATCH v8 13/13] MAINTAINERS: Add SLIMbus maintainer

[srinivas.kandagatla]

From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

Add myself as maintainer for slimbus.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 MAINTAINERS | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index aa71ab52fd76..f26bf2707709 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12500,6 +12500,14 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
 F:	include/linux/srcu.h
 F:	kernel/rcu/srcu.c
 
+SERIAL LOW-POWER INTER-CHIP MEDIA BUS (SLIMbus)
+M:	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
+L:	alsa-devel@alsa-project.org (moderated for non-subscribers)
+S:	Maintained
+F:	drivers/slimbus/
+F:	Documentation/devicetree/bindings/slimbus/
+F:	include/linux/slimbus.h
+
 SMACK SECURITY MODULE
 M:	Casey Schaufler <casey@schaufler-ca.com>
 L:	linux-security-module@vger.kernel.org
-- 
2.15.0

Re: [PATCH v8 07/13] slimbus: Add support for 'clock-pause' feature

[Philippe Ombredanne]

On Thu, Nov 30, 2017 at 6:41 PM,  <srinivas.kandagatla@linaro.org> wrote:
[]
> diff --git a/drivers/slimbus/sched.c b/drivers/slimbus/sched.c
> new file mode 100644
> index 000000000000..74300f1a6898
> --- /dev/null
> +++ b/drivers/slimbus/sched.c
> @@ -0,0 +1,128 @@
> +/* Copyright (c) 2011-2016, The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * 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.

Could it make sense to use the new SPDX ids here? e.g.

> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2011-2016, The Linux Foundation

This neat and cleaner, is it?
See tglx doc posted as patches and Linus comments for a rationale on
the comment styles.
--
Cordially
Philippe Ombredanne

Re: [PATCH v8 07/13] slimbus: Add support for 'clock-pause' feature

[Greg Kroah-Hartman]

On Thu, Nov 30, 2017 at 08:25:26PM +0100, Philippe Ombredanne wrote:
> On Thu, Nov 30, 2017 at 6:41 PM,  <srinivas.kandagatla@linaro.org> wrote:
> []
> > diff --git a/drivers/slimbus/sched.c b/drivers/slimbus/sched.c
> > new file mode 100644
> > index 000000000000..74300f1a6898
> > --- /dev/null
> > +++ b/drivers/slimbus/sched.c
> > @@ -0,0 +1,128 @@
> > +/* Copyright (c) 2011-2016, The Linux Foundation. All rights reserved.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 and
> > + * only version 2 as published by the Free Software Foundation.
> > + *
> > + * 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.
> 
> Could it make sense to use the new SPDX ids here? e.g.
> 
> > +// SPDX-License-Identifier: GPL-2.0
> > +// Copyright (c) 2011-2016, The Linux Foundation
> 
> This neat and cleaner, is it?
> See tglx doc posted as patches and Linus comments for a rationale on
> the comment styles.

Yes please, otherwise I'll just have to write add-on patches to do just
this :)

thanks,

greg k-h

Re: [PATCH v8 07/13] slimbus: Add support for 'clock-pause' feature

[Srinivas Kandagatla]

On 01/12/17 09:51, Greg Kroah-Hartman wrote:
> On Thu, Nov 30, 2017 at 08:25:26PM +0100, Philippe Ombredanne wrote:
>> On Thu, Nov 30, 2017 at 6:41 PM,<srinivas.kandagatla@linaro.org>  wrote:
>> []
>>> diff --git a/drivers/slimbus/sched.c b/drivers/slimbus/sched.c
>>> new file mode 100644
>>> index 000000000000..74300f1a6898
>>> --- /dev/null
>>> +++ b/drivers/slimbus/sched.c
>>> @@ -0,0 +1,128 @@
>>> +/* Copyright (c) 2011-2016, The Linux Foundation. All rights reserved.
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License version 2 and
>>> + * only version 2 as published by the Free Software Foundation.
>>> + *
>>> + * 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.
>> Could it make sense to use the new SPDX ids here? e.g.
>>
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +// Copyright (c) 2011-2016, The Linux Foundation
>> This neat and cleaner, is it?
>> See tglx doc posted as patches and Linus comments for a rationale on
>> the comment styles.
> Yes please, otherwise I'll just have to write add-on patches to do just
> this:)
> 
Yep, I will take care of this before sending another version.


Thanks,
srini


> thanks,
> 
> greg k-h

Re: [PATCH v8 01/13] Documentation: Add SLIMbus summary

[Jonathan Neuschäfer]

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Hi, some small nits below.

On Thu, Nov 30, 2017 at 05:41:48PM +0000, srinivas.kandagatla@linaro.org wrote:
> From: Sagar Dharia <sdharia@codeaurora.org>
> 
> SLIMbus (Serial Low Power Interchip Media Bus) is a specification
> developed by MIPI (Mobile Industry Processor Interface) alliance.
> SLIMbus is a 2-wire implementation, which is used to communicate with
> peripheral components like audio-codec.
> 
> The summary of SLIMbus and API is documented in the 'summary' file.
> 
> Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> ---
>  Documentation/driver-api/slimbus/index.rst   |  15 ++++
>  Documentation/driver-api/slimbus/summary.rst | 108 +++++++++++++++++++++++++++
>  2 files changed, 123 insertions(+)
>  create mode 100644 Documentation/driver-api/slimbus/index.rst
>  create mode 100644 Documentation/driver-api/slimbus/summary.rst

It would probably make sense to Cc the documentation maintainers/mailing
list on this patch (AFAICS, you didn't do that).

When do you plan to add slimbus to Documentation/driver-api/index.rst?

> diff --git a/Documentation/driver-api/slimbus/index.rst b/Documentation/driver-api/slimbus/index.rst
> new file mode 100644
> index 000000000000..586f979659e6
> --- /dev/null
> +++ b/Documentation/driver-api/slimbus/index.rst
> @@ -0,0 +1,15 @@
> +=====================
> +SLIMbus Documentation
> +=====================
> +
> +.. toctree::
> +   :maxdepth: 1
> +
> +   summary
> +
> +.. only::  subproject
> +
> +   Indices
> +   =======
> +
> +   * :ref:`genindex`
> diff --git a/Documentation/driver-api/slimbus/summary.rst b/Documentation/driver-api/slimbus/summary.rst
> new file mode 100644
> index 000000000000..ba165611725a
> --- /dev/null
> +++ b/Documentation/driver-api/slimbus/summary.rst
> @@ -0,0 +1,108 @@
> +============================
> +Linux kernel SLIMbus support
> +============================
> +
> +Overview
> +========
> +
> +What is SLIMbus?
> +----------------
> +SLIMbus (Serial Low Power Interchip Media Bus) is a specification developed by
> +MIPI (Mobile Industry Processor Interface) alliance. The bus uses master/slave
> +configuration, and is a 2-wire multi-drop implementation (clock, and data).
> +
> +Currently, SLIMbus is used to interface between application processors of SoCs
> +(System-on-Chip) and peripheral components (typically codec).SLIMbus uses
> +Time-Division-Multiplexing to accommodate multiple data channels, and
> +a control channel.
> +
> +The control channel is used for various control functions such as bus
> +management, configuration and status updates.These messages can be unicast (e.g.
                                               ^^ space after period, please

> +reading/writing device specific values), or multicast (e.g. data channel
> +reconfiguration sequence is a broadcast message announced to all devices)
> +
> +A data channel is used for data-transfer between 2 SLIMbus devices. Data
> +channel uses dedicated ports on the device.
> +
[...]
> +
> +Device notifications to the driver:
> +-----------------------------------
> +Since SLIMbus devices have mechanisms for reporting their presence, the
> +framework allows drivers to bind when corresponding devices report their
> +presence on the bus.
> +However, it is possible that the driver needs to be probed
> +first so that it can enable corresponding SLIMbus device (e.g. power it up and/or
> +take it out of reset). To support that behavior, the framework allows drivers
> +to probe first as well  (e.g. using standard DeviceTree compatbility field).

Typo: s/compatbility/compatibility/

> +This creates the necessity for the driver to know when the device is functional
> +(i.e. reported present). device_up callback is used for that reason when the
> +device reports present and is assigned a logical address by the controller.
> +
> +Similarly, SLIMbus devices 'report absent' when they go down. A 'device_down'
> +callback notifies the driver when the device reports absent and its logical
> +address assignment is invalidated by the controller.
> +
> +Another notification "boot_device" is used to notify the slim_driver when
> +controller resets the bus. This notification allows the driver to take necessary
> +steps to boot the device so that it's functional after the bus has been reset.
> +
> +Clock-pause:
> +------------
> +SLIMbus mandates that a reconfiguration sequence (known as clock-pause) be
> +broadcast to all active devices on the bus before the bus can enter low-power
> +mode. Controller uses this sequence when it decides to enter low-power mode so
> +that corresponding clocks and/or power-rails can be turned off to save power.
> +Clock-pause is exited by waking up framer device (if controller driver initiates
> +exiting low power mode), or by toggling the data line (if a slave device wants
> +to initiate it).
> +
> +Messaging APIs:
> +---------------
> +The framework supports APIs to exchange control-information with a SLIMbus
> +device. APIs can be synchronous or asynchronous.
> +From controller's perspective, multiple buffers can be queued to/from
> +hardware for sending/receiving data using slim_ctrl_buf circular buffer.
> +The header file <linux/slimbus.h> has more documentation about messaging APIs.

Once the kerneldoc documentation (i.e. the /** ... */ comments in the
source) is included somewhere, I think it would make sense to make
slim_ctrl_buf a clickable link to the struct's documentation.


Thanks,
Jonathan Neuschäfer

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Re: [PATCH v8 10/13] dt-bindings: Add qcom slimbus controller bindings

[Rob Herring]

On Thu, Nov 30, 2017 at 05:41:57PM +0000, srinivas.kandagatla@linaro.org wrote:
> From: Sagar Dharia <sdharia@codeaurora.org>
> 
> This patch add device tree bindings for Qualcomm slimbus controller.
> 
> Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> ---
>  .../devicetree/bindings/slimbus/slim-qcom-ctrl.txt | 39 ++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/slimbus/slim-qcom-ctrl.txt
> 
> diff --git a/Documentation/devicetree/bindings/slimbus/slim-qcom-ctrl.txt b/Documentation/devicetree/bindings/slimbus/slim-qcom-ctrl.txt
> new file mode 100644
> index 000000000000..93a6fdaf09b3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/slimbus/slim-qcom-ctrl.txt
> @@ -0,0 +1,39 @@
> +Qualcomm SLIMbus controller
> +This controller is used if applications processor driver controls SLIMbus
> +master component.
> +
> +Required properties:
> +
> + - #address-cells - refer to Documentation/devicetree/bindings/slimbus/bus.txt
> + - #size-cells	- refer to Documentation/devicetree/bindings/slimbus/bus.txt
> +
> + - reg : Offset and length of the register region(s) for the device
> + - reg-names : Register region name(s) referenced in reg above
> +	 Required register resource entries are:
> +	 "ctrl": Physical address of controller register blocks
> + 	 "slew": required for "qcom,apq8064-slim" SOC.
> + - compatible : should be "qcom,<SOC-NAME>-slim" for SOC specific compatible
> + 		followed by "qcom,slim" for fallback.
> + - interrupts : Interrupt number used by this controller
> + - clocks : Interface and core clocks used by this SLIMbus controller
> + - clock-names : Required clock-name entries are:
> +	"iface_clk" : Interface clock for this controller
> +	"core_clk" : Interrupt for controller core's BAM

Doesn't match the example. You should drop the '_clk'. With that,

Reviewed-by: Rob Herring <robh@kernel.org>

> +
> +Example:
> +
> +	slim@28080000 {
> +		compatible = "qcom,apq8064-slim", "qcom,slim";
> +		reg = <0x28080000 0x2000>, <0x80207C 4>;
> +		reg-names = "ctrl", "slew";
> +		interrupts = <0 33 0>;
> +		clocks = <&lcc SLIMBUS_SRC>, <&lcc AUDIO_SLIMBUS_CLK>;
> +		clock-names = "iface", "core";
> +		#address-cells = <2>;
> +		#size-cell = <0>;
> +
> +		wcd9310: audio-codec@1,0{
> +			compatible = "slim217,60";
> +			reg = <1 0>;
> +		};
> +	};
> -- 
> 2.15.0
> 

Re: [PATCH v8 01/13] Documentation: Add SLIMbus summary

[Srinivas Kandagatla]

Thanks for the review comments.

On 01/12/17 10:27, Jonathan Neuschäfer wrote:
> Hi, some small nits below.
> 
> On Thu, Nov 30, 2017 at 05:41:48PM +0000, srinivas.kandagatla@linaro.org wrote:
>> From: Sagar Dharia <sdharia@codeaurora.org>
>>
>> SLIMbus (Serial Low Power Interchip Media Bus) is a specification
>> developed by MIPI (Mobile Industry Processor Interface) alliance.
>> SLIMbus is a 2-wire implementation, which is used to communicate with
>> peripheral components like audio-codec.
>>
>> The summary of SLIMbus and API is documented in the 'summary' file.
>>
>> Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>> ---
>>   Documentation/driver-api/slimbus/index.rst   |  15 ++++
>>   Documentation/driver-api/slimbus/summary.rst | 108 +++++++++++++++++++++++++++
>>   2 files changed, 123 insertions(+)
>>   create mode 100644 Documentation/driver-api/slimbus/index.rst
>>   create mode 100644 Documentation/driver-api/slimbus/summary.rst
> 
> It would probably make sense to Cc the documentation maintainers/mailing
> list on this patch (AFAICS, you didn't do that).
> 
Yep, I will include them while sending next version.

> When do you plan to add slimbus to Documentation/driver-api/index.rst?

that's good point, I will fix this in next version.
> 

>> +framework allows drivers to bind when corresponding devices report their
>> +presence on the bus.
>> +However, it is possible that the driver needs to be probed
>> +first so that it can enable corresponding SLIMbus device (e.g. power it up and/or
>> +take it out of reset). To support that behavior, the framework allows drivers
>> +to probe first as well  (e.g. using standard DeviceTree compatbility field).
> 
> Typo: s/compatbility/compatibility/
Yep, Will fix in next version.

> 
>> +---------------
>> +The framework supports APIs to exchange control-information with a SLIMbus
>> +device. APIs can be synchronous or asynchronous.
>> +From controller's perspective, multiple buffers can be queued to/from
>> +hardware for sending/receiving data using slim_ctrl_buf circular buffer.
>> +The header file <linux/slimbus.h> has more documentation about messaging APIs.
> 
> Once the kerneldoc documentation (i.e. the /** ... */ comments in the
> source) is included somewhere, I think it would make sense to make
> slim_ctrl_buf a clickable link to the struct's documentation.
Sure, I will explore this side of it before i send next version.

thanks,
srini
> 
> 
> Thanks,
> Jonathan Neuschäfer
> 

Re: [PATCH v8 10/13] dt-bindings: Add qcom slimbus controller bindings

[Srinivas Kandagatla]

On 04/12/17 21:28, Rob Herring wrote:
> On Thu, Nov 30, 2017 at 05:41:57PM +0000, srinivas.kandagatla@linaro.org wrote:
>> From: Sagar Dharia <sdharia@codeaurora.org>
>>
>> This patch add device tree bindings for Qualcomm slimbus controller.
>>
>> Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>> ---
>>   .../devicetree/bindings/slimbus/slim-qcom-ctrl.txt | 39 ++++++++++++++++++++++
>>   1 file changed, 39 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/slimbus/slim-qcom-ctrl.txt
>>
>> + - clocks : Interface and core clocks used by this SLIMbus controller
>> + - clock-names : Required clock-name entries are:
>> +	"iface_clk" : Interface clock for this controller
>> +	"core_clk" : Interrupt for controller core's BAM
> 
> Doesn't match the example. You should drop the '_clk'. With that,
> 

Thanks for the Reviewed-by tag, I will fix the above in next version.

> Reviewed-by: Rob Herring <robh@kernel.org>