[RFCv3 2/3] interconnect: Add imx core driver

[Leonard Crestez <leonard.crestez@nxp.com>]

This adds support for i.MX SoC family to interconnect framework.

Platform drivers can describe their interconnect graph and
several adjustment knobs where an icc node bandwith converted to a
clk_min_rate request.

All adjustable nodes are assumed to be independent.

Based on an earlier work by Alexandre Bailon but greatly reduced to drop
"platform opp" support.

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
---
 drivers/interconnect/Kconfig      |   1 +
 drivers/interconnect/Makefile     |   1 +
 drivers/interconnect/imx/Kconfig  |   5 +
 drivers/interconnect/imx/Makefile |   1 +
 drivers/interconnect/imx/imx.c    | 258 ++++++++++++++++++++++++++++++
 drivers/interconnect/imx/imx.h    |  62 +++++++
 6 files changed, 328 insertions(+)
 create mode 100644 drivers/interconnect/imx/Kconfig
 create mode 100644 drivers/interconnect/imx/Makefile
 create mode 100644 drivers/interconnect/imx/imx.c
 create mode 100644 drivers/interconnect/imx/imx.h

diff --git a/drivers/interconnect/Kconfig b/drivers/interconnect/Kconfig
index bfa4ca3ab7a9..e61802230f90 100644
--- a/drivers/interconnect/Kconfig
+++ b/drivers/interconnect/Kconfig
@@ -10,7 +10,8 @@ menuconfig INTERCONNECT
 	  If unsure, say no.
 
 if INTERCONNECT
 
 source "drivers/interconnect/qcom/Kconfig"
+source "drivers/interconnect/imx/Kconfig"
 
 endif
diff --git a/drivers/interconnect/Makefile b/drivers/interconnect/Makefile
index 28f2ab0824d5..20a13b7eb37f 100644
--- a/drivers/interconnect/Makefile
+++ b/drivers/interconnect/Makefile
@@ -2,5 +2,6 @@
 
 icc-core-objs				:= core.o
 
 obj-$(CONFIG_INTERCONNECT)		+= icc-core.o
 obj-$(CONFIG_INTERCONNECT_QCOM)		+= qcom/
+obj-$(CONFIG_INTERCONNECT_IMX)		+= imx/
diff --git a/drivers/interconnect/imx/Kconfig b/drivers/interconnect/imx/Kconfig
new file mode 100644
index 000000000000..45fbae7007af
--- /dev/null
+++ b/drivers/interconnect/imx/Kconfig
@@ -0,0 +1,5 @@
+config INTERCONNECT_IMX
+	bool "i.MX interconnect drivers"
+	depends on ARCH_MXC || ARCH_MXC_ARM64 || COMPILE_TEST
+	help
+	  Generic interconnect driver for i.MX SOCs
diff --git a/drivers/interconnect/imx/Makefile b/drivers/interconnect/imx/Makefile
new file mode 100644
index 000000000000..bb92fd9fe4a5
--- /dev/null
+++ b/drivers/interconnect/imx/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_INTERCONNECT_IMX) += imx.o
diff --git a/drivers/interconnect/imx/imx.c b/drivers/interconnect/imx/imx.c
new file mode 100644
index 000000000000..cc838e40419e
--- /dev/null
+++ b/drivers/interconnect/imx/imx.c
@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Interconnect framework driver for i.MX SoC
+ *
+ * Copyright (c) 2019, BayLibre
+ * Copyright (c) 2019, NXP
+ * Author: Alexandre Bailon <abailon@baylibre.com>
+ * Author: Leonard Crestez <leonard.crestez@nxp.com>
+ */
+
+#include <linux/device.h>
+#include <linux/interconnect-provider.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_qos.h>
+#include <linux/devfreq.h>
+#include <linux/of.h>
+
+#include "imx.h"
+
+/* private icc_provider data */
+struct imx_icc_provider {
+	struct device *dev;
+};
+
+/* private icc_node data */
+struct imx_icc_node {
+	const struct imx_icc_node_desc *desc;
+	struct devfreq *devfreq;
+	struct dev_pm_qos_request qos_req;
+};
+
+static int imx_icc_aggregate(struct icc_node *node, u32 avg_bw,
+				  u32 peak_bw, u32 *agg_avg, u32 *agg_peak)
+{
+	*agg_avg += avg_bw;
+	*agg_peak = max(*agg_peak, peak_bw);
+
+	return 0;
+}
+
+static struct icc_node* imx_icc_xlate(struct of_phandle_args *spec, void *data)
+{
+	struct imx_icc_provider *desc = data;
+	struct icc_provider *provider = dev_get_drvdata(desc->dev);
+	unsigned int id = spec->args[0];
+	struct icc_node *node;
+
+	list_for_each_entry (node, &provider->nodes, node_list)
+		if (node->id == id)
+			return node;
+
+	return ERR_PTR(-EINVAL);
+}
+
+static int imx_icc_node_set(struct icc_node *node)
+{
+	struct device *dev = node->provider->dev;
+	struct imx_icc_node *node_data = node->data;
+	unsigned long freq;
+
+	if (!node_data->devfreq)
+		return 0;
+
+	freq = (node->avg_bw + node->peak_bw) * node_data->desc->adj->bw_mul;
+	do_div(freq, node_data->desc->adj->bw_div);
+	if (freq > INT_MAX) {
+		dev_err(dev, "%s can't request more INT_MAX freq\n",
+				node->name);
+		return -ERANGE;
+	}
+
+	dev_dbg(dev, "%s avg_bw %u peak_bw %u min_freq %lu\n",
+			node->name, node->avg_bw, node->peak_bw, freq);
+
+	dev_pm_qos_update_request(&node_data->qos_req, freq);
+
+	return 0;
+}
+
+static int imx_icc_set(struct icc_node *src, struct icc_node *dst)
+{
+	return imx_icc_node_set(dst);
+}
+
+static int imx_icc_node_init_devfreq(struct device *dev, 
+				     struct icc_node *node)
+{
+	struct imx_icc_node *node_data = node->data;
+	const struct imx_icc_node_desc *node_desc = node_data->desc;
+	int index;
+	int ret;
+
+	index = of_property_match_string(dev->of_node,
+			"devfreq-names", node_desc->adj->devfreq_name);
+	if (index < 0) {
+		dev_err(dev, "failed to match devfreq-names %s: %d\n",
+				node_desc->adj->devfreq_name, index);
+		return index;
+	}
+
+	node_data->devfreq = devfreq_get_devfreq_by_phandle(dev, index);
+	if (IS_ERR(node_data->devfreq)) {
+		ret = PTR_ERR(node_data->devfreq);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "failed to fetch devfreq %d %s: %d\n",
+					index, node_desc->adj->devfreq_name, ret);
+		return ret;
+	}
+
+	return dev_pm_qos_add_request(node_data->devfreq->dev.parent,
+			&node_data->qos_req,
+			DEV_PM_QOS_MIN_FREQUENCY, 0);
+}
+
+static struct icc_node *imx_icc_node_add(struct icc_provider *provider,
+					 const struct imx_icc_node_desc *node_desc)
+{
+	struct imx_icc_provider *provider_data = provider->data;
+	struct device *dev = provider_data->dev;
+	struct imx_icc_node *node_data;
+	struct icc_node *node;
+	int ret;
+
+	node = icc_node_create(node_desc->id);
+	if (IS_ERR(node)) {
+		dev_err(dev, "failed to create node %d\n", node_desc->id);
+		return node;
+	}
+
+	if (node->data) {
+		dev_err(dev, "already created node %s id=%d\n",
+				node_desc->name, node_desc->id);
+		return ERR_PTR(-EEXIST);
+	}
+
+	node_data = devm_kzalloc(dev, sizeof(*node_data), GFP_KERNEL);
+	if (!node_data) {
+		icc_node_destroy(node->id);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	node->name = node_desc->name;
+	node->data = node_data;
+	node_data->desc = node_desc;
+	if (node_desc->adj) {
+		ret = imx_icc_node_init_devfreq(dev, node);
+		if (ret < 0) {
+			icc_node_destroy(node->id);
+			return ERR_PTR(ret);
+		}
+	}
+
+	icc_node_add(node, provider);
+
+	return node;
+}
+
+static void imx_icc_unregister_nodes(struct icc_provider *provider)
+{
+	struct icc_node *node, *tmp;
+
+	list_for_each_entry_safe(node, tmp, &provider->nodes, node_list) {
+		struct imx_icc_node *node_data = node->data;
+
+		icc_node_del(node);
+		icc_node_destroy(node->id);
+		if (dev_pm_qos_request_active(&node_data->qos_req))
+			dev_pm_qos_remove_request(&node_data->qos_req);
+	}
+}
+
+static int imx_icc_register_nodes(struct icc_provider *provider,
+				  const struct imx_icc_node_desc *descs,
+				  int count)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < count; i++) {
+		struct icc_node *node;
+		const struct imx_icc_node_desc *node_desc = &descs[i];
+		size_t j;
+
+		node = imx_icc_node_add(provider, node_desc);
+		if (IS_ERR(node)) {
+			ret = PTR_ERR(node);
+			if (ret != -EPROBE_DEFER)
+				dev_err(provider->dev, "failed to add %s: %d\n",
+						node_desc->name, ret);
+			goto err;
+		}
+
+		for (j = 0; j < node_desc->num_links; j++)
+			icc_link_create(node, node_desc->links[j]);
+	}
+
+	return 0;
+
+err:
+	imx_icc_unregister_nodes(provider);
+
+	return ret;
+}
+
+int imx_icc_register(struct platform_device *pdev,
+		     struct imx_icc_node_desc *nodes, int nodes_count)
+{
+	struct device *dev = &pdev->dev;
+	struct imx_icc_provider *desc;
+	struct icc_provider *provider;
+	int ret;
+
+	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+	desc->dev = dev;
+
+	provider = devm_kzalloc(dev, sizeof(*provider), GFP_KERNEL);
+	if (!provider)
+		return -ENOMEM;
+	provider->set = imx_icc_set;
+	provider->aggregate = imx_icc_aggregate;
+	provider->xlate = imx_icc_xlate;
+	provider->data = desc;
+	provider->dev = dev;
+	platform_set_drvdata(pdev, provider);
+
+	ret = icc_provider_add(provider);
+	if (ret) {
+		dev_err(dev, "error adding interconnect provider\n");
+		return ret;
+	}
+
+	ret = imx_icc_register_nodes(provider, nodes, nodes_count);
+	if (ret) {
+		dev_err(dev, "error adding interconnect nodes\n");
+		goto provider_del;
+	}
+
+	return 0;
+
+provider_del:
+	icc_provider_del(provider);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(imx_icc_register);
+
+int imx_icc_unregister(struct platform_device *pdev)
+{
+	struct icc_provider *provider = platform_get_drvdata(pdev);
+
+	icc_provider_del(provider);
+	imx_icc_unregister_nodes(provider);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(imx_icc_unregister);
diff --git a/drivers/interconnect/imx/imx.h b/drivers/interconnect/imx/imx.h
new file mode 100644
index 000000000000..ab191eb89616
--- /dev/null
+++ b/drivers/interconnect/imx/imx.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Interconnect framework driver for i.MX SoC
+ *
+ * Copyright (c) 2019, BayLibre
+ * Copyright (c) 2019, NXP
+ * Author: Alexandre Bailon <abailon@baylibre.com>
+ * Author: Leonard Crestez <leonard.crestez@nxp.com>
+ */
+#ifndef __BUSFREQ_H
+#define __BUSFREQ_H
+
+#include <linux/kernel.h>
+
+#define IMX_ICC_MAX_LINKS	32
+#define IMX_ICC_UNDEFINED_BW	0xffffffff
+
+/*
+ * struct imx_icc_node_adj - Describe an dynamic adjustment knob
+ */
+struct imx_icc_node_adj_desc {
+	const char *devfreq_name;
+	unsigned int bw_mul, bw_div;
+};
+
+/*
+ * struct imx_icc_node - Describe an interconnect node
+ * @name: name of the node
+ * @id: an unique id to identify the node
+ * @links: an array of slaves' node id
+ * @num_links: number of id defined in links
+ */
+struct imx_icc_node_desc {
+	const char *name;
+	u16 id;
+	u16 links[IMX_ICC_MAX_LINKS];
+	u16 num_links;
+
+	const struct imx_icc_node_adj_desc *adj;
+};
+
+#define DEFINE_BUS_INTERCONNECT(_name, _id, _adj, _numlinks, ...)	\
+	{								\
+		.id = _id,						\
+		.name = _name,						\
+		.adj = _adj,						\
+		.num_links = _numlinks,					\
+		.links = { __VA_ARGS__ },				\
+	}
+
+#define DEFINE_BUS_MASTER(_name, _id, _dest_id)				\
+	DEFINE_BUS_INTERCONNECT(_name, _id, NULL, 1, _dest_id)
+
+#define DEFINE_BUS_SLAVE(_name, _id, _adj)				\
+	DEFINE_BUS_INTERCONNECT(_name, _id, _adj, 0)
+
+int imx_icc_register(struct platform_device *pdev,
+		     struct imx_icc_node_desc *nodes,
+		     int nodes_count);
+int imx_icc_unregister(struct platform_device *pdev);
+
+#endif /* __BUSFREQ_H */
-- 
2.17.1