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/slim-core.c | 15 +++++ drivers/slimbus/slim-messaging.c | 50 ++++++++++++++-- drivers/slimbus/slim-sched.c | 126 +++++++++++++++++++++++++++++++++++++++ include/linux/slimbus.h | 54 ++++++++++++++++- 5 files changed, 239 insertions(+), 8 deletions(-) create mode 100644 drivers/slimbus/slim-sched.c
diff --git a/drivers/slimbus/Makefile b/drivers/slimbus/Makefile index ed8521a..8fc8b50 100644 --- a/drivers/slimbus/Makefile +++ b/drivers/slimbus/Makefile @@ -2,7 +2,7 @@ # Makefile for kernel slimbus framework. # obj-$(CONFIG_SLIMBUS) += slimbus.o -slimbus-y := slim-core.o slim-messaging.o +slimbus-y := slim-core.o slim-messaging.o slim-sched.o
#Controllers obj-$(CONFIG_SLIM_QCOM_CTRL) += slim-qcom-ctrl.o diff --git a/drivers/slimbus/slim-core.c b/drivers/slimbus/slim-core.c index 5b1da28..a5cb31b 100644 --- a/drivers/slimbus/slim-core.c +++ b/drivers/slimbus/slim-core.c @@ -364,6 +364,8 @@ int slim_register_controller(struct slim_controller *ctrl) mutex_init(&ctrl->m_ctrl); spin_lock_init(&ctrl->tx.lock); spin_lock_init(&ctrl->rx.lock); + mutex_init(&ctrl->sched.m_reconf); + init_completion(&ctrl->sched.pause_comp);
ctrl->pending_wr = kcalloc((ctrl->tx.n - 1), sizeof(struct slim_pending), @@ -432,6 +434,8 @@ int slim_del_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);
destroy_workqueue(ctrl->wq);
@@ -585,6 +589,14 @@ int slim_assign_laddr(struct slim_controller *ctrl, struct slim_eaddr *e_addr, struct slim_device *slim; struct slim_addrt *temp;
+ ret = pm_runtime_get_sync(ctrl->dev.parent); + + 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; + } + mutex_lock(&ctrl->m_ctrl); /* already assigned */ if (ctrl_getaddr_entry(ctrl, e_addr, &i) == 0) { @@ -655,6 +667,9 @@ int slim_assign_laddr(struct slim_controller *ctrl, struct slim_eaddr *e_addr, } mutex_unlock(&slim->report_lock); } +slimbus_not_active: + pm_runtime_mark_last_busy(ctrl->dev.parent); + pm_runtime_put_autosuspend(ctrl->dev.parent); return ret; } EXPORT_SYMBOL_GPL(slim_assign_laddr); diff --git a/drivers/slimbus/slim-messaging.c b/drivers/slimbus/slim-messaging.c index adcba67..f6a0fa2 100644 --- a/drivers/slimbus/slim-messaging.c +++ b/drivers/slimbus/slim-messaging.c @@ -10,6 +10,7 @@ * GNU General Public License for more details. */ #include <linux/slab.h> +#include <linux/pm_runtime.h> #include <linux/slimbus.h>
/** @@ -43,6 +44,9 @@ void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 len) memcpy(msg->rbuf, reply, len); if (msg->comp_cb) msg->comp_cb(msg->ctx, 0); + /* Remove runtime-pm vote now that response was received for TID txn */ + pm_runtime_mark_last_busy(ctrl->dev.parent); + pm_runtime_put_autosuspend(ctrl->dev.parent); } EXPORT_SYMBOL_GPL(slim_msg_response);
@@ -77,11 +81,21 @@ int slim_processtxn(struct slim_controller *ctrl, int ret, i = 0; unsigned long flags; u8 *buf; - bool async = false; + bool async = false, clk_pause_msg = false; struct slim_cb_data cbd; DECLARE_COMPLETION_ONSTACK(done); bool need_tid = slim_tid_txn(txn->mt, txn->mc);
+ /* + * 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 (!txn->msg->comp_cb) { txn->msg->comp_cb = slim_sync_default_cb; cbd.comp = &done; @@ -90,7 +104,7 @@ int slim_processtxn(struct slim_controller *ctrl, async = true; }
- buf = slim_get_tx(ctrl, txn, need_tid); + buf = slim_get_tx(ctrl, txn, need_tid, clk_pause_msg); if (!buf) return -ENOMEM;
@@ -104,7 +118,8 @@ int slim_processtxn(struct slim_controller *ctrl, if (ctrl->last_tid == (SLIM_MAX_TIDS - 1)) { spin_unlock_irqrestore(&ctrl->txn_lock, flags); slim_return_tx(ctrl, -ENOMEM); - return -ENOMEM; + ret = cbd.ret; + return ret; } ctrl->last_tid++; } @@ -429,6 +444,14 @@ void slim_return_tx(struct slim_controller *ctrl, int err) cur.cb(cur.ctx, err);
up(&ctrl->tx_sem); + if (!cur.clk_pause && (!cur.need_tid || err)) { + /** + * remove runtime-pm vote if this was TX only, or + * if there was error during this transaction + */ + pm_runtime_mark_last_busy(ctrl->dev.parent); + pm_runtime_put_autosuspend(ctrl->dev.parent); + } } EXPORT_SYMBOL_GPL(slim_return_tx);
@@ -441,15 +464,25 @@ EXPORT_SYMBOL_GPL(slim_return_tx); * back to the pool. */ void *slim_get_tx(struct slim_controller *ctrl, struct slim_msg_txn *txn, - bool need_tid) + bool need_tid, bool clk_pause) { unsigned long flags; int ret, idx;
+ if (!clk_pause) { + ret = pm_runtime_get_sync(ctrl->dev.parent); + + 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_tx_err; + } + } + ret = down_interruptible(&ctrl->tx_sem); if (ret < 0) { dev_err(&ctrl->dev, "TX semaphore down returned:%d", ret); - return NULL; + goto slim_tx_err; } spin_lock_irqsave(&ctrl->tx.lock, flags);
@@ -457,15 +490,20 @@ void *slim_get_tx(struct slim_controller *ctrl, struct slim_msg_txn *txn, spin_unlock_irqrestore(&ctrl->tx.lock, flags); dev_err(&ctrl->dev, "controller TX buf unavailable"); up(&ctrl->tx_sem); - return NULL; + goto slim_tx_err; } idx = ctrl->tx.tail; ctrl->tx.tail = (ctrl->tx.tail + 1) % ctrl->tx.n; ctrl->pending_wr[idx].cb = txn->msg->comp_cb; ctrl->pending_wr[idx].ctx = txn->msg->ctx; ctrl->pending_wr[idx].need_tid = need_tid; + ctrl->pending_wr[idx].clk_pause = clk_pause; spin_unlock_irqrestore(&ctrl->tx.lock, flags);
return ctrl->tx.base + (idx * ctrl->tx.sl_sz); +slim_tx_err: + pm_runtime_mark_last_busy(ctrl->dev.parent); + pm_runtime_put_autosuspend(ctrl->dev.parent); + return NULL; } EXPORT_SYMBOL_GPL(slim_get_tx); diff --git a/drivers/slimbus/slim-sched.c b/drivers/slimbus/slim-sched.c new file mode 100644 index 0000000..3ed075f --- /dev/null +++ b/drivers/slimbus/slim-sched.c @@ -0,0 +1,126 @@ +/* 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 <linux/slimbus.h> + +/** + * slim_ctrl_clk_pause: Called by slimbus controller to enter/exit 'clock pause' + * 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. + * @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. + * 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, 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 < ctrl->last_tid; i++) { + /* Pending response for a message */ + if (ctrl->tid_tbl[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_processtxn(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_processtxn(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_processtxn(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/include/linux/slimbus.h b/include/linux/slimbus.h index 080d86a..549f78f 100644 --- a/include/linux/slimbus.h +++ b/include/linux/slimbus.h @@ -117,11 +117,21 @@ struct slim_addrt { #define SLIM_MSG_MC_REPLY_VALUE 0x64 #define SLIM_MSG_MC_CHANGE_VALUE 0x68
+/* 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 + /* Destination type Values */ #define SLIM_MSG_DEST_LOGICALADDR 0 #define SLIM_MSG_DEST_ENUMADDR 1 #define SLIM_MSG_DEST_BROADCAST 3
+/* Clock pause values per slimbus spec */ +#define SLIM_CLK_FAST 0 +#define SLIM_CLK_CONST_PHASE 1 +#define SLIM_CLK_UNSPECIFIED 2 + /** * struct slim_val_inf: Slimbus value or information element * @start_offset: Specifies starting offset in information/value element map @@ -205,11 +215,46 @@ struct slim_ctrl_buf { * @cb: callback for this transfer * @ctx: contex for the callback function * @need_tid: True if this transfer need Transaction ID + * @clk_pause: True if this transfer is part of clock-pause sequence */ struct slim_pending { void (*cb)(void *ctx, int err); void *ctx; bool need_tid; + bool clk_pause; +}; + +/** + * 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 { + int clkgear; + enum slim_clk_state clk_state; + struct completion pause_comp; + struct mutex m_reconf; };
/** @@ -256,6 +301,7 @@ struct slim_pending { * @pending_wr: Pending write transactions to be acknowledged by controller * @tx_sem: Semaphore for available TX buffers for this controller * @last_tid: Last used entry for TID 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. @@ -265,6 +311,9 @@ struct slim_pending { * @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. + * @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. */ struct slim_controller { struct device dev; @@ -285,12 +334,14 @@ struct slim_controller { struct slim_ctrl_buf rx; struct slim_pending *pending_wr; struct semaphore tx_sem; + struct slim_sched sched; int (*xfer_msg)(struct slim_controller *ctrl, struct slim_msg_txn *tx, void *buf); 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); };
#define to_slim_controller(d) container_of(d, struct slim_controller, dev) @@ -444,7 +495,7 @@ int slim_processtxn(struct slim_controller *ctrl, struct slim_msg_txn *txn); void *slim_get_rx(struct slim_controller *ctrl); int slim_return_rx(struct slim_controller *ctrl, void *buf); void *slim_get_tx(struct slim_controller *ctrl, struct slim_msg_txn *txn, - bool need_tid); + bool need_tid, bool clk_pause); void slim_return_tx(struct slim_controller *ctrl, int err);
static inline bool slim_tid_txn(u8 mt, u8 mc) @@ -456,5 +507,6 @@ static inline bool slim_tid_txn(u8 mt, u8 mc) mc == SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION)); } /* end of message apis */ +int slim_ctrl_clk_pause(struct slim_controller *ctrl, bool wakeup, u8 restart);
#endif /* _LINUX_SLIMBUS_H */