Merge branch 'icc-cbf' into icc-next

On MSM8996 two CPU clusters are interconnected using the Core Bus
Fabric (CBF). In order for the CPU clusters to function properly, it
should be clocked following the core's frequencies to provide adequate
bandwidth.

Register CBF as a clock (required for CPU to boot) and add a tiny
interconnect layer on top of it to let cpufreq/opp scale the CBF clock.

* icc-cbf
  dt-bindings: interconnect/msm8996-cbf: add defines to be used by CBF
  interconnect: add clk-based icc provider support
  clk: qcom: cbf-msm8996: scale CBF clock according to the CPUfreq
  interconnect: icc-clk: fix modular build

Link: https://lore.kernel.org/r/20230512001334.2983048-1-dmitry.baryshkov@linaro.org
Signed-off-by: Georgi Djakov <djakov@kernel.org>

3 files changed, 182 insertions, 0 deletions

diff --git a/drivers/interconnect/Kconfig b/drivers/interconnect/Kconfig
index d637a89d4695..5faa8d2aecff 100644
--- a/drivers/interconnect/Kconfig
+++ b/drivers/interconnect/Kconfig
@@ -15,4 +15,10 @@ source "drivers/interconnect/imx/Kconfig"
 source "drivers/interconnect/qcom/Kconfig"
 source "drivers/interconnect/samsung/Kconfig"
 
+config INTERCONNECT_CLK
+	tristate
+	depends on COMMON_CLK
+	help
+	  Support for wrapping clocks into the interconnect nodes.
+
 endif
diff --git a/drivers/interconnect/Makefile b/drivers/interconnect/Makefile
index 97d393fd638d..5604ce351a9f 100644
--- a/drivers/interconnect/Makefile
+++ b/drivers/interconnect/Makefile
@@ -7,3 +7,5 @@ obj-$(CONFIG_INTERCONNECT)		+= icc-core.o
 obj-$(CONFIG_INTERCONNECT_IMX)		+= imx/
 obj-$(CONFIG_INTERCONNECT_QCOM)		+= qcom/
 obj-$(CONFIG_INTERCONNECT_SAMSUNG)	+= samsung/
+
+obj-$(CONFIG_INTERCONNECT_CLK)		+= icc-clk.o
diff --git a/drivers/interconnect/icc-clk.c b/drivers/interconnect/icc-clk.c
new file mode 100644
index 000000000000..4d43ebff4257
--- /dev/null
+++ b/drivers/interconnect/icc-clk.c
@@ -0,0 +1,174 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023, Linaro Ltd.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/interconnect-clk.h>
+#include <linux/interconnect-provider.h>
+
+struct icc_clk_node {
+	struct clk *clk;
+	bool enabled;
+};
+
+struct icc_clk_provider {
+	struct icc_provider provider;
+	int num_clocks;
+	struct icc_clk_node clocks[];
+};
+
+#define to_icc_clk_provider(_provider) \
+	container_of(_provider, struct icc_clk_provider, provider)
+
+static int icc_clk_set(struct icc_node *src, struct icc_node *dst)
+{
+	struct icc_clk_node *qn = src->data;
+	int ret;
+
+	if (!qn || !qn->clk)
+		return 0;
+
+	if (!src->peak_bw) {
+		if (qn->enabled)
+			clk_disable_unprepare(qn->clk);
+		qn->enabled = false;
+
+		return 0;
+	}
+
+	if (!qn->enabled) {
+		ret = clk_prepare_enable(qn->clk);
+		if (ret)
+			return ret;
+		qn->enabled = true;
+	}
+
+	return clk_set_rate(qn->clk, icc_units_to_bps(src->peak_bw));
+}
+
+static int icc_clk_get_bw(struct icc_node *node, u32 *avg, u32 *peak)
+{
+	struct icc_clk_node *qn = node->data;
+
+	if (!qn || !qn->clk)
+		*peak = INT_MAX;
+	else
+		*peak = Bps_to_icc(clk_get_rate(qn->clk));
+
+	return 0;
+}
+
+/**
+ * icc_clk_register() - register a new clk-based interconnect provider
+ * @dev: device supporting this provider
+ * @first_id: an ID of the first provider's node
+ * @num_clocks: number of instances of struct icc_clk_data
+ * @data: data for the provider
+ *
+ * Registers and returns a clk-based interconnect provider. It is a simple
+ * wrapper around COMMON_CLK framework, allowing other devices to vote on the
+ * clock rate.
+ *
+ * Return: 0 on success, or an error code otherwise
+ */
+struct icc_provider *icc_clk_register(struct device *dev,
+				      unsigned int first_id,
+				      unsigned int num_clocks,
+				      const struct icc_clk_data *data)
+{
+	struct icc_clk_provider *qp;
+	struct icc_provider *provider;
+	struct icc_onecell_data *onecell;
+	struct icc_node *node;
+	int ret, i, j;
+
+	onecell = devm_kzalloc(dev, struct_size(onecell, nodes, 2 * num_clocks), GFP_KERNEL);
+	if (!onecell)
+		return ERR_PTR(-ENOMEM);
+
+	qp = devm_kzalloc(dev, struct_size(qp, clocks, num_clocks), GFP_KERNEL);
+	if (!qp)
+		return ERR_PTR(-ENOMEM);
+
+	qp->num_clocks = num_clocks;
+
+	provider = &qp->provider;
+	provider->dev = dev;
+	provider->get_bw = icc_clk_get_bw;
+	provider->set = icc_clk_set;
+	provider->aggregate = icc_std_aggregate;
+	provider->xlate = of_icc_xlate_onecell;
+	INIT_LIST_HEAD(&provider->nodes);
+	provider->data = onecell;
+
+	icc_provider_init(provider);
+
+	for (i = 0, j = 0; i < num_clocks; i++) {
+		qp->clocks[i].clk = data[i].clk;
+
+		node = icc_node_create(first_id + j);
+		if (IS_ERR(node)) {
+			ret = PTR_ERR(node);
+			goto err;
+		}
+
+		node->name = devm_kasprintf(dev, GFP_KERNEL, "%s_master", data[i].name);
+		node->data = &qp->clocks[i];
+		icc_node_add(node, provider);
+		/* link to the next node, slave */
+		icc_link_create(node, first_id + j + 1);
+		onecell->nodes[j++] = node;
+
+		node = icc_node_create(first_id + j);
+		if (IS_ERR(node)) {
+			ret = PTR_ERR(node);
+			goto err;
+		}
+
+		node->name = devm_kasprintf(dev, GFP_KERNEL, "%s_slave", data[i].name);
+		/* no data for slave node */
+		icc_node_add(node, provider);
+		onecell->nodes[j++] = node;
+	}
+
+	onecell->num_nodes = j;
+
+	ret = icc_provider_register(provider);
+	if (ret)
+		goto err;
+
+	return provider;
+
+err:
+	icc_nodes_remove(provider);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(icc_clk_register);
+
+/**
+ * icc_clk_unregister() - unregister a previously registered clk interconnect provider
+ * @provider: provider returned by icc_clk_register()
+ */
+void icc_clk_unregister(struct icc_provider *provider)
+{
+	struct icc_clk_provider *qp = container_of(provider, struct icc_clk_provider, provider);
+	int i;
+
+	icc_provider_deregister(&qp->provider);
+	icc_nodes_remove(&qp->provider);
+
+	for (i = 0; i < qp->num_clocks; i++) {
+		struct icc_clk_node *qn = &qp->clocks[i];
+
+		if (qn->enabled)
+			clk_disable_unprepare(qn->clk);
+	}
+}
+EXPORT_SYMBOL_GPL(icc_clk_unregister);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Interconnect wrapper for clocks");
+MODULE_AUTHOR("Dmitry Baryshkov <dmitry.baryshkov@linaro.org>");