1 files changed, 313 insertions, 0 deletions
diff --git a/drivers/net/ipa/ipa_clock.c b/drivers/net/ipa/ipa_clock.c
new file mode 100644
index 000000000000..374491ea11cf
--- /dev/null
+++ b/drivers/net/ipa/ipa_clock.c
@@ -0,0 +1,313 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
+ * Copyright (C) 2018-2020 Linaro Ltd.
+ */
+
+#include <linux/atomic.h>
+#include <linux/mutex.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/interconnect.h>
+
+#include "ipa.h"
+#include "ipa_clock.h"
+#include "ipa_modem.h"
+
+/**
+ * DOC: IPA Clocking
+ *
+ * The "IPA Clock" manages both the IPA core clock and the interconnects
+ * (buses) the IPA depends on as a single logical entity.  A reference count
+ * is incremented by "get" operations and decremented by "put" operations.
+ * Transitions of that count from 0 to 1 result in the clock and interconnects
+ * being enabled, and transitions of the count from 1 to 0 cause them to be
+ * disabled.  We currently operate the core clock at a fixed clock rate, and
+ * all buses at a fixed average and peak bandwidth.  As more advanced IPA
+ * features are enabled, we can make better use of clock and bus scaling.
+ *
+ * An IPA clock reference must be held for any access to IPA hardware.
+ */
+
+#define	IPA_CORE_CLOCK_RATE		(75UL * 1000 * 1000)	/* Hz */
+
+/* Interconnect path bandwidths (each times 1000 bytes per second) */
+#define IPA_MEMORY_AVG			(80 * 1000)	/* 80 MBps */
+#define IPA_MEMORY_PEAK			(600 * 1000)
+
+#define IPA_IMEM_AVG			(80 * 1000)
+#define IPA_IMEM_PEAK			(350 * 1000)
+
+#define IPA_CONFIG_AVG			(40 * 1000)
+#define IPA_CONFIG_PEAK			(40 * 1000)
+
+/**
+ * struct ipa_clock - IPA clocking information
+ * @count:		Clocking reference count
+ * @mutex;		Protects clock enable/disable
+ * @core:		IPA core clock
+ * @memory_path:	Memory interconnect
+ * @imem_path:		Internal memory interconnect
+ * @config_path:	Configuration space interconnect
+ */
+struct ipa_clock {
+	atomic_t count;
+	struct mutex mutex; /* protects clock enable/disable */
+	struct clk *core;
+	struct icc_path *memory_path;
+	struct icc_path *imem_path;
+	struct icc_path *config_path;
+};
+
+static struct icc_path *
+ipa_interconnect_init_one(struct device *dev, const char *name)
+{
+	struct icc_path *path;
+
+	path = of_icc_get(dev, name);
+	if (IS_ERR(path))
+		dev_err(dev, "error %ld getting memory interconnect\n",
+			PTR_ERR(path));
+
+	return path;
+}
+
+/* Initialize interconnects required for IPA operation */
+static int ipa_interconnect_init(struct ipa_clock *clock, struct device *dev)
+{
+	struct icc_path *path;
+
+	path = ipa_interconnect_init_one(dev, "memory");
+	if (IS_ERR(path))
+		goto err_return;
+	clock->memory_path = path;
+
+	path = ipa_interconnect_init_one(dev, "imem");
+	if (IS_ERR(path))
+		goto err_memory_path_put;
+	clock->imem_path = path;
+
+	path = ipa_interconnect_init_one(dev, "config");
+	if (IS_ERR(path))
+		goto err_imem_path_put;
+	clock->config_path = path;
+
+	return 0;
+
+err_imem_path_put:
+	icc_put(clock->imem_path);
+err_memory_path_put:
+	icc_put(clock->memory_path);
+err_return:
+	return PTR_ERR(path);
+}
+
+/* Inverse of ipa_interconnect_init() */
+static void ipa_interconnect_exit(struct ipa_clock *clock)
+{
+	icc_put(clock->config_path);
+	icc_put(clock->imem_path);
+	icc_put(clock->memory_path);
+}
+
+/* Currently we only use one bandwidth level, so just "enable" interconnects */
+static int ipa_interconnect_enable(struct ipa *ipa)
+{
+	struct ipa_clock *clock = ipa->clock;
+	int ret;
+
+	ret = icc_set_bw(clock->memory_path, IPA_MEMORY_AVG, IPA_MEMORY_PEAK);
+	if (ret)
+		return ret;
+
+	ret = icc_set_bw(clock->imem_path, IPA_IMEM_AVG, IPA_IMEM_PEAK);
+	if (ret)
+		goto err_memory_path_disable;
+
+	ret = icc_set_bw(clock->config_path, IPA_CONFIG_AVG, IPA_CONFIG_PEAK);
+	if (ret)
+		goto err_imem_path_disable;
+
+	return 0;
+
+err_imem_path_disable:
+	(void)icc_set_bw(clock->imem_path, 0, 0);
+err_memory_path_disable:
+	(void)icc_set_bw(clock->memory_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_clock *clock = ipa->clock;
+	int ret;
+
+	ret = icc_set_bw(clock->memory_path, 0, 0);
+	if (ret)
+		return ret;
+
+	ret = icc_set_bw(clock->imem_path, 0, 0);
+	if (ret)
+		goto err_memory_path_reenable;
+
+	ret = icc_set_bw(clock->config_path, 0, 0);
+	if (ret)
+		goto err_imem_path_reenable;
+
+	return 0;
+
+err_imem_path_reenable:
+	(void)icc_set_bw(clock->imem_path, IPA_IMEM_AVG, IPA_IMEM_PEAK);
+err_memory_path_reenable:
+	(void)icc_set_bw(clock->memory_path, IPA_MEMORY_AVG, IPA_MEMORY_PEAK);
+
+	return ret;
+}
+
+/* Turn on IPA clocks, including interconnects */
+static int ipa_clock_enable(struct ipa *ipa)
+{
+	int ret;
+
+	ret = ipa_interconnect_enable(ipa);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(ipa->clock->core);
+	if (ret)
+		ipa_interconnect_disable(ipa);
+
+	return ret;
+}
+
+/* Inverse of ipa_clock_enable() */
+static void ipa_clock_disable(struct ipa *ipa)
+{
+	clk_disable_unprepare(ipa->clock->core);
+	(void)ipa_interconnect_disable(ipa);
+}
+
+/* Get an IPA clock reference, but only if the reference count is
+ * already non-zero.  Returns true if the additional reference was
+ * added successfully, or false otherwise.
+ */
+bool ipa_clock_get_additional(struct ipa *ipa)
+{
+	return !!atomic_inc_not_zero(&ipa->clock->count);
+}
+
+/* Get an IPA clock reference.  If the reference count is non-zero, it is
+ * incremented and return is immediate.  Otherwise it is checked again
+ * under protection of the mutex, and if appropriate the clock (and
+ * interconnects) are enabled suspended endpoints (if any) are resumed
+ * before returning.
+ *
+ * Incrementing the reference count is intentionally deferred until
+ * after the clock is running and endpoints are resumed.
+ */
+void ipa_clock_get(struct ipa *ipa)
+{
+	struct ipa_clock *clock = ipa->clock;
+	int ret;
+
+	/* If the clock is running, just bump the reference count */
+	if (ipa_clock_get_additional(ipa))
+		return;
+
+	/* Otherwise get the mutex and check again */
+	mutex_lock(&clock->mutex);
+
+	/* A reference might have been added before we got the mutex. */
+	if (ipa_clock_get_additional(ipa))
+		goto out_mutex_unlock;
+
+	ret = ipa_clock_enable(ipa);
+	if (ret) {
+		dev_err(&ipa->pdev->dev, "error %d enabling IPA clock\n", ret);
+		goto out_mutex_unlock;
+	}
+
+	ipa_endpoint_resume(ipa);
+
+	atomic_inc(&clock->count);
+
+out_mutex_unlock:
+	mutex_unlock(&clock->mutex);
+}
+
+/* Attempt to remove an IPA clock reference.  If this represents the last
+ * reference, suspend endpoints and disable the clock (and interconnects)
+ * under protection of a mutex.
+ */
+void ipa_clock_put(struct ipa *ipa)
+{
+	struct ipa_clock *clock = ipa->clock;
+
+	/* If this is not the last reference there's nothing more to do */
+	if (!atomic_dec_and_mutex_lock(&clock->count, &clock->mutex))
+		return;
+
+	ipa_endpoint_suspend(ipa);
+
+	ipa_clock_disable(ipa);
+
+	mutex_unlock(&clock->mutex);
+}
+
+/* Initialize IPA clocking */
+struct ipa_clock *ipa_clock_init(struct device *dev)
+{
+	struct ipa_clock *clock;
+	struct clk *clk;
+	int ret;
+
+	clk = clk_get(dev, "core");
+	if (IS_ERR(clk)) {
+		dev_err(dev, "error %ld getting core clock\n", PTR_ERR(clk));
+		return ERR_CAST(clk);
+	}
+
+	ret = clk_set_rate(clk, IPA_CORE_CLOCK_RATE);
+	if (ret) {
+		dev_err(dev, "error %d setting core clock rate to %lu\n",
+			ret, IPA_CORE_CLOCK_RATE);
+		goto err_clk_put;
+	}
+
+	clock = kzalloc(sizeof(*clock), GFP_KERNEL);
+	if (!clock) {
+		ret = -ENOMEM;
+		goto err_clk_put;
+	}
+	clock->core = clk;
+
+	ret = ipa_interconnect_init(clock, dev);
+	if (ret)
+		goto err_kfree;
+
+	mutex_init(&clock->mutex);
+	atomic_set(&clock->count, 0);
+
+	return clock;
+
+err_kfree:
+	kfree(clock);
+err_clk_put:
+	clk_put(clk);
+
+	return ERR_PTR(ret);
+}
+
+/* Inverse of ipa_clock_init() */
+void ipa_clock_exit(struct ipa_clock *clock)
+{
+	struct clk *clk = clock->core;
+
+	WARN_ON(atomic_read(&clock->count) != 0);
+	mutex_destroy(&clock->mutex);
+	ipa_interconnect_exit(clock);
+	kfree(clock);
+	clk_put(clk);
+}