slimbus: Add support for 'clock-pause' feature (4b14e62a) · Commits · e / devices / android_kernel_fairphone_FP5

drivers/slimbus/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -3,4 +3,4 @@
		# Makefile for kernel SLIMbus framework.
		#
		obj-$(CONFIG_SLIMBUS) += slimbus.o
		slimbus-y := core.o messaging.o
		slimbus-y := core.o messaging.o sched.o

drivers/slimbus/core.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -9,6 +9,7 @@
		#include <linux/init.h>
		#include <linux/idr.h>
		#include <linux/of.h>
		#include <linux/pm_runtime.h>
		#include <linux/slimbus.h>
		#include "slimbus.h"

		@@ -218,6 +219,8 @@ 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);
		@@ -249,6 +252,8 @@ 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;
		@@ -416,6 +421,14 @@ 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;
		@@ -427,6 +440,9 @@ 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);

drivers/slimbus/messaging.c

+34 −1

Original line number	Diff line number	Diff line
		@@ -4,6 +4,7 @@
		*/

		#include <linux/slab.h>
		#include <linux/pm_runtime.h>
		#include "slimbus.h"

		/**
		@@ -46,6 +47,10 @@ 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);

		@@ -65,10 +70,29 @@ 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 = false, 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) {
		@@ -107,6 +131,15 @@ 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;
		}
		EXPORT_SYMBOL_GPL(slim_do_transfer);

drivers/slimbus/sched.c

0 → 100644

+121 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		/*
		* Copyright (c) 2011-2017, The Linux Foundation
		*/

		#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);

drivers/slimbus/slimbus.h

+53 −0

Original line number	Diff line number	Diff line
		@@ -14,6 +14,16 @@
		/* 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
		@@ -80,6 +90,42 @@ 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)
		@@ -95,6 +141,7 @@ 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.
		@@ -105,6 +152,9 @@ 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.
		@@ -139,12 +189,14 @@ 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,
		@@ -154,6 +206,7 @@ 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)
		{