1 files changed, 473 insertions, 0 deletions
diff --git a/drivers/net/ipa/ipa_power.c b/drivers/net/ipa/ipa_power.c
new file mode 100644
index 000000000000..b1c6c0fcb654
--- /dev/null
+++ b/drivers/net/ipa/ipa_power.c
@@ -0,0 +1,473 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
+ * Copyright (C) 2018-2021 Linaro Ltd.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/interconnect.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/bitops.h>
+
+#include "ipa.h"
+#include "ipa_power.h"
+#include "ipa_endpoint.h"
+#include "ipa_modem.h"
+#include "ipa_data.h"
+
+/**
+ * DOC: IPA Power Management
+ *
+ * The IPA hardware is enabled when the IPA core clock and all the
+ * interconnects (buses) it depends on are enabled.  Runtime power
+ * management is used to determine whether the core clock and
+ * interconnects are enabled, and if not in use to be suspended
+ * automatically.
+ *
+ * The core clock currently runs at a fixed clock rate when enabled,
+ * an all interconnects use a fixed average and peak bandwidth.
+ */
+
+#define IPA_AUTOSUSPEND_DELAY	500	/* milliseconds */
+
+/**
+ * struct ipa_interconnect - IPA interconnect information
+ * @path:		Interconnect path
+ * @average_bandwidth:	Average interconnect bandwidth (KB/second)
+ * @peak_bandwidth:	Peak interconnect bandwidth (KB/second)
+ */
+struct ipa_interconnect {
+	struct icc_path *path;
+	u32 average_bandwidth;
+	u32 peak_bandwidth;
+};
+
+/**
+ * enum ipa_power_flag - IPA power flags
+ * @IPA_POWER_FLAG_RESUMED:	Whether resume from suspend has been signaled
+ * @IPA_POWER_FLAG_SYSTEM:	Hardware is system (not runtime) suspended
+ * @IPA_POWER_FLAG_STOPPED:	Modem TX is disabled by ipa_start_xmit()
+ * @IPA_POWER_FLAG_STARTED:	Modem TX was enabled by ipa_runtime_resume()
+ * @IPA_POWER_FLAG_COUNT:	Number of defined power flags
+ */
+enum ipa_power_flag {
+	IPA_POWER_FLAG_RESUMED,
+	IPA_POWER_FLAG_SYSTEM,
+	IPA_POWER_FLAG_STOPPED,
+	IPA_POWER_FLAG_STARTED,
+	IPA_POWER_FLAG_COUNT,		/* Last; not a flag */
+};
+
+/**
+ * struct ipa_power - IPA power management information
+ * @dev:		IPA device pointer
+ * @core:		IPA core clock
+ * @spinlock:		Protects modem TX queue enable/disable
+ * @flags:		Boolean state flags
+ * @interconnect_count:	Number of elements in interconnect[]
+ * @interconnect:	Interconnect array
+ */
+struct ipa_power {
+	struct device *dev;
+	struct clk *core;
+	spinlock_t spinlock;	/* used with STOPPED/STARTED power flags */
+	DECLARE_BITMAP(flags, IPA_POWER_FLAG_COUNT);
+	u32 interconnect_count;
+	struct ipa_interconnect *interconnect;
+};
+
+static int ipa_interconnect_init_one(struct device *dev,
+				     struct ipa_interconnect *interconnect,
+				     const struct ipa_interconnect_data *data)
+{
+	struct icc_path *path;
+
+	path = of_icc_get(dev, data->name);
+	if (IS_ERR(path)) {
+		int ret = PTR_ERR(path);
+
+		dev_err_probe(dev, ret, "error getting %s interconnect\n",
+			      data->name);
+
+		return ret;
+	}
+
+	interconnect->path = path;
+	interconnect->average_bandwidth = data->average_bandwidth;
+	interconnect->peak_bandwidth = data->peak_bandwidth;
+
+	return 0;
+}
+
+static void ipa_interconnect_exit_one(struct ipa_interconnect *interconnect)
+{
+	icc_put(interconnect->path);
+	memset(interconnect, 0, sizeof(*interconnect));
+}
+
+/* Initialize interconnects required for IPA operation */
+static int ipa_interconnect_init(struct ipa_power *power, struct device *dev,
+				 const struct ipa_interconnect_data *data)
+{
+	struct ipa_interconnect *interconnect;
+	u32 count;
+	int ret;
+
+	count = power->interconnect_count;
+	interconnect = kcalloc(count, sizeof(*interconnect), GFP_KERNEL);
+	if (!interconnect)
+		return -ENOMEM;
+	power->interconnect = interconnect;
+
+	while (count--) {
+		ret = ipa_interconnect_init_one(dev, interconnect, data++);
+		if (ret)
+			goto out_unwind;
+		interconnect++;
+	}
+
+	return 0;
+
+out_unwind:
+	while (interconnect-- > power->interconnect)
+		ipa_interconnect_exit_one(interconnect);
+	kfree(power->interconnect);
+	power->interconnect = NULL;
+
+	return ret;
+}
+
+/* Inverse of ipa_interconnect_init() */
+static void ipa_interconnect_exit(struct ipa_power *power)
+{
+	struct ipa_interconnect *interconnect;
+
+	interconnect = power->interconnect + power->interconnect_count;
+	while (interconnect-- > power->interconnect)
+		ipa_interconnect_exit_one(interconnect);
+	kfree(power->interconnect);
+	power->interconnect = NULL;
+}
+
+/* Currently we only use one bandwidth level, so just "enable" interconnects */
+static int ipa_interconnect_enable(struct ipa *ipa)
+{
+	struct ipa_interconnect *interconnect;
+	struct ipa_power *power = ipa->power;
+	int ret;
+	u32 i;
+
+	interconnect = power->interconnect;
+	for (i = 0; i < power->interconnect_count; i++) {
+		ret = icc_set_bw(interconnect->path,
+				 interconnect->average_bandwidth,
+				 interconnect->peak_bandwidth);
+		if (ret) {
+			dev_err(&ipa->pdev->dev,
+				"error %d enabling %s interconnect\n",
+				ret, icc_get_name(interconnect->path));
+			goto out_unwind;
+		}
+		interconnect++;
+	}
+
+	return 0;
+
+out_unwind:
+	while (interconnect-- > power->interconnect)
+		(void)icc_set_bw(interconnect->path, 0, 0);
+
+	return ret;
+}
+
+/* To disable an interconnect, we just its bandwidth to 0 */
+static int ipa_interconnect_disable(struct ipa *ipa)
+{
+	struct ipa_interconnect *interconnect;
+	struct ipa_power *power = ipa->power;
+	struct device *dev = &ipa->pdev->dev;
+	int result = 0;
+	u32 count;
+	int ret;
+
+	count = power->interconnect_count;
+	interconnect = power->interconnect + count;
+	while (count--) {
+		interconnect--;
+		ret = icc_set_bw(interconnect->path, 0, 0);
+		if (ret) {
+			dev_err(dev, "error %d disabling %s interconnect\n",
+				ret, icc_get_name(interconnect->path));
+			/* Try to disable all; record only the first error */
+			if (!result)
+				result = ret;
+		}
+	}
+
+	return result;
+}
+
+/* Enable IPA power, enabling interconnects and the core clock */
+static int ipa_power_enable(struct ipa *ipa)
+{
+	int ret;
+
+	ret = ipa_interconnect_enable(ipa);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(ipa->power->core);
+	if (ret) {
+		dev_err(&ipa->pdev->dev, "error %d enabling core clock\n", ret);
+		(void)ipa_interconnect_disable(ipa);
+	}
+
+	return ret;
+}
+
+/* Inverse of ipa_power_enable() */
+static int ipa_power_disable(struct ipa *ipa)
+{
+	clk_disable_unprepare(ipa->power->core);
+
+	return ipa_interconnect_disable(ipa);
+}
+
+static int ipa_runtime_suspend(struct device *dev)
+{
+	struct ipa *ipa = dev_get_drvdata(dev);
+
+	/* Endpoints aren't usable until setup is complete */
+	if (ipa->setup_complete) {
+		__clear_bit(IPA_POWER_FLAG_RESUMED, ipa->power->flags);
+		ipa_endpoint_suspend(ipa);
+		gsi_suspend(&ipa->gsi);
+	}
+
+	return ipa_power_disable(ipa);
+}
+
+static int ipa_runtime_resume(struct device *dev)
+{
+	struct ipa *ipa = dev_get_drvdata(dev);
+	int ret;
+
+	ret = ipa_power_enable(ipa);
+	if (WARN_ON(ret < 0))
+		return ret;
+
+	/* Endpoints aren't usable until setup is complete */
+	if (ipa->setup_complete) {
+		gsi_resume(&ipa->gsi);
+		ipa_endpoint_resume(ipa);
+	}
+
+	return 0;
+}
+
+static int ipa_suspend(struct device *dev)
+{
+	struct ipa *ipa = dev_get_drvdata(dev);
+
+	__set_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags);
+
+	return pm_runtime_force_suspend(dev);
+}
+
+static int ipa_resume(struct device *dev)
+{
+	struct ipa *ipa = dev_get_drvdata(dev);
+	int ret;
+
+	ret = pm_runtime_force_resume(dev);
+
+	__clear_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags);
+
+	return ret;
+}
+
+/* Return the current IPA core clock rate */
+u32 ipa_core_clock_rate(struct ipa *ipa)
+{
+	return ipa->power ? (u32)clk_get_rate(ipa->power->core) : 0;
+}
+
+/**
+ * ipa_suspend_handler() - Handle the suspend IPA interrupt
+ * @ipa:	IPA pointer
+ * @irq_id:	IPA interrupt type (unused)
+ *
+ * If an RX endpoint is suspended, and the IPA has a packet destined for
+ * that endpoint, the IPA generates a SUSPEND interrupt to inform the AP
+ * that it should resume the endpoint.  If we get one of these interrupts
+ * we just wake up the system.
+ */
+static void ipa_suspend_handler(struct ipa *ipa, enum ipa_irq_id irq_id)
+{
+	/* To handle an IPA interrupt we will have resumed the hardware
+	 * just to handle the interrupt, so we're done.  If we are in a
+	 * system suspend, trigger a system resume.
+	 */
+	if (!__test_and_set_bit(IPA_POWER_FLAG_RESUMED, ipa->power->flags))
+		if (test_bit(IPA_POWER_FLAG_SYSTEM, ipa->power->flags))
+			pm_wakeup_dev_event(&ipa->pdev->dev, 0, true);
+
+	/* Acknowledge/clear the suspend interrupt on all endpoints */
+	ipa_interrupt_suspend_clear_all(ipa->interrupt);
+}
+
+/* The next few functions coordinate stopping and starting the modem
+ * network device transmit queue.
+ *
+ * Transmit can be running concurrent with power resume, and there's a
+ * chance the resume completes before the transmit path stops the queue,
+ * leaving the queue in a stopped state.  The next two functions are used
+ * to avoid this: ipa_power_modem_queue_stop() is used by ipa_start_xmit()
+ * to conditionally stop the TX queue; and ipa_power_modem_queue_start()
+ * is used by ipa_runtime_resume() to conditionally restart it.
+ *
+ * Two flags and a spinlock are used.  If the queue is stopped, the STOPPED
+ * power flag is set.  And if the queue is started, the STARTED flag is set.
+ * The queue is only started on resume if the STOPPED flag is set.  And the
+ * queue is only started in ipa_start_xmit() if the STARTED flag is *not*
+ * set.  As a result, the queue remains operational if the two activites
+ * happen concurrently regardless of the order they complete.  The spinlock
+ * ensures the flag and TX queue operations are done atomically.
+ *
+ * The first function stops the modem netdev transmit queue, but only if
+ * the STARTED flag is *not* set.  That flag is cleared if it was set.
+ * If the queue is stopped, the STOPPED flag is set.  This is called only
+ * from the power ->runtime_resume operation.
+ */
+void ipa_power_modem_queue_stop(struct ipa *ipa)
+{
+	struct ipa_power *power = ipa->power;
+	unsigned long flags;
+
+	spin_lock_irqsave(&power->spinlock, flags);
+
+	if (!__test_and_clear_bit(IPA_POWER_FLAG_STARTED, power->flags)) {
+		netif_stop_queue(ipa->modem_netdev);
+		__set_bit(IPA_POWER_FLAG_STOPPED, power->flags);
+	}
+
+	spin_unlock_irqrestore(&power->spinlock, flags);
+}
+
+/* This function starts the modem netdev transmit queue, but only if the
+ * STOPPED flag is set.  That flag is cleared if it was set.  If the queue
+ * was restarted, the STARTED flag is set; this allows ipa_start_xmit()
+ * to skip stopping the queue in the event of a race.
+ */
+void ipa_power_modem_queue_wake(struct ipa *ipa)
+{
+	struct ipa_power *power = ipa->power;
+	unsigned long flags;
+
+	spin_lock_irqsave(&power->spinlock, flags);
+
+	if (__test_and_clear_bit(IPA_POWER_FLAG_STOPPED, power->flags)) {
+		__set_bit(IPA_POWER_FLAG_STARTED, power->flags);
+		netif_wake_queue(ipa->modem_netdev);
+	}
+
+	spin_unlock_irqrestore(&power->spinlock, flags);
+}
+
+/* This function clears the STARTED flag once the TX queue is operating */
+void ipa_power_modem_queue_active(struct ipa *ipa)
+{
+	clear_bit(IPA_POWER_FLAG_STARTED, ipa->power->flags);
+}
+
+int ipa_power_setup(struct ipa *ipa)
+{
+	int ret;
+
+	ipa_interrupt_add(ipa->interrupt, IPA_IRQ_TX_SUSPEND,
+			  ipa_suspend_handler);
+
+	ret = device_init_wakeup(&ipa->pdev->dev, true);
+	if (ret)
+		ipa_interrupt_remove(ipa->interrupt, IPA_IRQ_TX_SUSPEND);
+
+	return ret;
+}
+
+void ipa_power_teardown(struct ipa *ipa)
+{
+	(void)device_init_wakeup(&ipa->pdev->dev, false);
+	ipa_interrupt_remove(ipa->interrupt, IPA_IRQ_TX_SUSPEND);
+}
+
+/* Initialize IPA power management */
+struct ipa_power *
+ipa_power_init(struct device *dev, const struct ipa_power_data *data)
+{
+	struct ipa_power *power;
+	struct clk *clk;
+	int ret;
+
+	clk = clk_get(dev, "core");
+	if (IS_ERR(clk)) {
+		dev_err_probe(dev, PTR_ERR(clk), "error getting core clock\n");
+
+		return ERR_CAST(clk);
+	}
+
+	ret = clk_set_rate(clk, data->core_clock_rate);
+	if (ret) {
+		dev_err(dev, "error %d setting core clock rate to %u\n",
+			ret, data->core_clock_rate);
+		goto err_clk_put;
+	}
+
+	power = kzalloc(sizeof(*power), GFP_KERNEL);
+	if (!power) {
+		ret = -ENOMEM;
+		goto err_clk_put;
+	}
+	power->dev = dev;
+	power->core = clk;
+	spin_lock_init(&power->spinlock);
+	power->interconnect_count = data->interconnect_count;
+
+	ret = ipa_interconnect_init(power, dev, data->interconnect_data);
+	if (ret)
+		goto err_kfree;
+
+	pm_runtime_set_autosuspend_delay(dev, IPA_AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_enable(dev);
+
+	return power;
+
+err_kfree:
+	kfree(power);
+err_clk_put:
+	clk_put(clk);
+
+	return ERR_PTR(ret);
+}
+
+/* Inverse of ipa_power_init() */
+void ipa_power_exit(struct ipa_power *power)
+{
+	struct device *dev = power->dev;
+	struct clk *clk = power->core;
+
+	pm_runtime_disable(dev);
+	pm_runtime_dont_use_autosuspend(dev);
+	ipa_interconnect_exit(power);
+	kfree(power);
+	clk_put(clk);
+}
+
+const struct dev_pm_ops ipa_pm_ops = {
+	.suspend		= ipa_suspend,
+	.resume			= ipa_resume,
+	.runtime_suspend	= ipa_runtime_suspend,
+	.runtime_resume		= ipa_runtime_resume,
+};