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authorSagar Dharia <sdharia@codeaurora.org>2017-12-12 02:42:58 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-12-19 13:01:02 +0300
commit46a2bb5a7f7ea2728be50f8f5b29a20267f700fe (patch)
tree593f156be08b9ac363e5f10d9db6e12cae8a7ea3 /drivers/slimbus/slimbus.h
parent3648e78ec701843ff8fab461071ba05067274f26 (diff)
downloadlinux-46a2bb5a7f7ea2728be50f8f5b29a20267f700fe.tar.xz
slimbus: core: Add slim controllers support
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> Reviwed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/slimbus/slimbus.h')
-rw-r--r--drivers/slimbus/slimbus.h108
1 files changed, 108 insertions, 0 deletions
diff --git a/drivers/slimbus/slimbus.h b/drivers/slimbus/slimbus.h
new file mode 100644
index 000000000000..66657722f50f
--- /dev/null
+++ b/drivers/slimbus/slimbus.h
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2011-2017, The Linux Foundation
+ */
+
+#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 */