interconnect: qcom: Add OSM L3 interconnect provider support

On some Qualcomm SoCs, Operating State Manager (OSM) controls the
resources of scaling L3 caches. Add a driver to handle bandwidth
requests to OSM L3 from CPU on SDM845 SoCs.

Signed-off-by: Sibi Sankar <[e-mail]>
Reviewed-by: Evan Green <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Georgi Djakov <[e-mail]>

drivers/interconnect/qcom/Kconfig

···
 	 This is a driver for the Qualcomm Network-on-Chip on msm8974-based
 	 platforms.
 
+config INTERCONNECT_QCOM_OSM_L3
+	tristate "Qualcomm OSM L3 interconnect driver"
+	depends on INTERCONNECT_QCOM || COMPILE_TEST
+	help
+	  Say y here to support the Operating State Manager (OSM) interconnect
+	  driver which controls the scaling of L3 caches on Qualcomm SoCs.
+
 config INTERCONNECT_QCOM_QCS404
 	tristate "Qualcomm QCS404 interconnect driver"
 	depends on INTERCONNECT_QCOM

drivers/interconnect/qcom/Makefile

···
 icc-bcm-voter-objs			:= bcm-voter.o
 qnoc-msm8916-objs			:= msm8916.o
 qnoc-msm8974-objs			:= msm8974.o
+icc-osm-l3-objs				:= osm-l3.o
 qnoc-qcs404-objs			:= qcs404.o
 icc-rpmh-obj				:= icc-rpmh.o
 qnoc-sc7180-objs			:= sc7180.o
···
 obj-$(CONFIG_INTERCONNECT_QCOM_BCM_VOTER) += icc-bcm-voter.o
 obj-$(CONFIG_INTERCONNECT_QCOM_MSM8916) += qnoc-msm8916.o
 obj-$(CONFIG_INTERCONNECT_QCOM_MSM8974) += qnoc-msm8974.o
+obj-$(CONFIG_INTERCONNECT_QCOM_OSM_L3) += icc-osm-l3.o
 obj-$(CONFIG_INTERCONNECT_QCOM_QCS404) += qnoc-qcs404.o
 obj-$(CONFIG_INTERCONNECT_QCOM_RPMH) += icc-rpmh.o
 obj-$(CONFIG_INTERCONNECT_QCOM_SC7180) += qnoc-sc7180.o

drivers/interconnect/qcom/osm-l3.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2020, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/interconnect-provider.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#include <dt-bindings/interconnect/qcom,osm-l3.h>
+
+#include "sdm845.h"
+
+#define LUT_MAX_ENTRIES			40U
+#define LUT_SRC				GENMASK(31, 30)
+#define LUT_L_VAL			GENMASK(7, 0)
+#define LUT_ROW_SIZE			32
+#define CLK_HW_DIV			2
+
+/* Register offsets */
+#define REG_ENABLE			0x0
+#define REG_FREQ_LUT			0x110
+#define REG_PERF_STATE			0x920
+
+#define OSM_L3_MAX_LINKS		1
+
+#define to_qcom_provider(_provider) \
+	container_of(_provider, struct qcom_osm_l3_icc_provider, provider)
+
+struct qcom_osm_l3_icc_provider {
+	void __iomem *base;
+	unsigned int max_state;
+	unsigned long lut_tables[LUT_MAX_ENTRIES];
+	struct icc_provider provider;
+};
+
+/**
+ * struct qcom_icc_node - Qualcomm specific interconnect nodes
+ * @name: the node name used in debugfs
+ * @links: an array of nodes where we can go next while traversing
+ * @id: a unique node identifier
+ * @num_links: the total number of @links
+ * @buswidth: width of the interconnect between a node and the bus
+ */
+struct qcom_icc_node {
+	const char *name;
+	u16 links[OSM_L3_MAX_LINKS];
+	u16 id;
+	u16 num_links;
+	u16 buswidth;
+};
+
+struct qcom_icc_desc {
+	struct qcom_icc_node **nodes;
+	size_t num_nodes;
+};
+
+#define DEFINE_QNODE(_name, _id, _buswidth, ...)			\
+		static struct qcom_icc_node _name = {			\
+		.name = #_name,						\
+		.id = _id,						\
+		.buswidth = _buswidth,					\
+		.num_links = ARRAY_SIZE(((int[]){ __VA_ARGS__ })),	\
+		.links = { __VA_ARGS__ },				\
+	}
+
+DEFINE_QNODE(sdm845_osm_apps_l3, SDM845_MASTER_OSM_L3_APPS, 16, SDM845_SLAVE_OSM_L3);
+DEFINE_QNODE(sdm845_osm_l3, SDM845_SLAVE_OSM_L3, 16);
+
+static struct qcom_icc_node *sdm845_osm_l3_nodes[] = {
+	[MASTER_OSM_L3_APPS] = &sdm845_osm_apps_l3,
+	[SLAVE_OSM_L3] = &sdm845_osm_l3,
+};
+
+const static struct qcom_icc_desc sdm845_icc_osm_l3 = {
+	.nodes = sdm845_osm_l3_nodes,
+	.num_nodes = ARRAY_SIZE(sdm845_osm_l3_nodes),
+};
+
+static int qcom_icc_set(struct icc_node *src, struct icc_node *dst)
+{
+	struct qcom_osm_l3_icc_provider *qp;
+	struct icc_provider *provider;
+	struct qcom_icc_node *qn;
+	struct icc_node *n;
+	unsigned int index;
+	u32 agg_peak = 0;
+	u32 agg_avg = 0;
+	u64 rate;
+
+	qn = src->data;
+	provider = src->provider;
+	qp = to_qcom_provider(provider);
+
+	list_for_each_entry(n, &provider->nodes, node_list)
+		provider->aggregate(n, 0, n->avg_bw, n->peak_bw,
+				    &agg_avg, &agg_peak);
+
+	rate = max(agg_avg, agg_peak);
+	rate = icc_units_to_bps(rate);
+	do_div(rate, qn->buswidth);
+
+	for (index = 0; index < qp->max_state - 1; index++) {
+		if (qp->lut_tables[index] >= rate)
+			break;
+	}
+
+	writel_relaxed(index, qp->base + REG_PERF_STATE);
+
+	return 0;
+}
+
+static int qcom_osm_l3_remove(struct platform_device *pdev)
+{
+	struct qcom_osm_l3_icc_provider *qp = platform_get_drvdata(pdev);
+
+	icc_nodes_remove(&qp->provider);
+	return icc_provider_del(&qp->provider);
+}
+
+static int qcom_osm_l3_probe(struct platform_device *pdev)
+{
+	u32 info, src, lval, i, prev_freq = 0, freq;
+	static unsigned long hw_rate, xo_rate;
+	struct qcom_osm_l3_icc_provider *qp;
+	const struct qcom_icc_desc *desc;
+	struct icc_onecell_data *data;
+	struct icc_provider *provider;
+	struct qcom_icc_node **qnodes;
+	struct icc_node *node;
+	size_t num_nodes;
+	struct clk *clk;
+	int ret;
+
+	clk = clk_get(&pdev->dev, "xo");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	xo_rate = clk_get_rate(clk);
+	clk_put(clk);
+
+	clk = clk_get(&pdev->dev, "alternate");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	hw_rate = clk_get_rate(clk) / CLK_HW_DIV;
+	clk_put(clk);
+
+	qp = devm_kzalloc(&pdev->dev, sizeof(*qp), GFP_KERNEL);
+	if (!qp)
+		return -ENOMEM;
+
+	qp->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(qp->base))
+		return PTR_ERR(qp->base);
+
+	/* HW should be in enabled state to proceed */
+	if (!(readl_relaxed(qp->base + REG_ENABLE) & 0x1)) {
+		dev_err(&pdev->dev, "error hardware not enabled\n");
+		return -ENODEV;
+	}
+
+	for (i = 0; i < LUT_MAX_ENTRIES; i++) {
+		info = readl_relaxed(qp->base + REG_FREQ_LUT +
+				     i * LUT_ROW_SIZE);
+		src = FIELD_GET(LUT_SRC, info);
+		lval = FIELD_GET(LUT_L_VAL, info);
+		if (src)
+			freq = xo_rate * lval;
+		else
+			freq = hw_rate;
+
+		/* Two of the same frequencies signify end of table */
+		if (i > 0 && prev_freq == freq)
+			break;
+
+		dev_dbg(&pdev->dev, "index=%d freq=%d\n", i, freq);
+
+		qp->lut_tables[i] = freq;
+		prev_freq = freq;
+	}
+	qp->max_state = i;
+
+	desc = device_get_match_data(&pdev->dev);
+	if (!desc)
+		return -EINVAL;
+
+	qnodes = desc->nodes;
+	num_nodes = desc->num_nodes;
+
+	data = devm_kcalloc(&pdev->dev, num_nodes, sizeof(*node), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	provider = &qp->provider;
+	provider->dev = &pdev->dev;
+	provider->set = qcom_icc_set;
+	provider->aggregate = icc_std_aggregate;
+	provider->xlate = of_icc_xlate_onecell;
+	INIT_LIST_HEAD(&provider->nodes);
+	provider->data = data;
+
+	ret = icc_provider_add(provider);
+	if (ret) {
+		dev_err(&pdev->dev, "error adding interconnect provider\n");
+		return ret;
+	}
+
+	for (i = 0; i < num_nodes; i++) {
+		size_t j;
+
+		node = icc_node_create(qnodes[i]->id);
+		if (IS_ERR(node)) {
+			ret = PTR_ERR(node);
+			goto err;
+		}
+
+		node->name = qnodes[i]->name;
+		node->data = qnodes[i];
+		icc_node_add(node, provider);
+
+		for (j = 0; j < qnodes[i]->num_links; j++)
+			icc_link_create(node, qnodes[i]->links[j]);
+
+		data->nodes[i] = node;
+	}
+	data->num_nodes = num_nodes;
+
+	platform_set_drvdata(pdev, qp);
+
+	return 0;
+err:
+	icc_nodes_remove(provider);
+	icc_provider_del(provider);
+
+	return ret;
+}
+
+static const struct of_device_id osm_l3_of_match[] = {
+	{ .compatible = "qcom,sdm845-osm-l3", .data = &sdm845_icc_osm_l3 },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, osm_l3_of_match);
+
+static struct platform_driver osm_l3_driver = {
+	.probe = qcom_osm_l3_probe,
+	.remove = qcom_osm_l3_remove,
+	.driver = {
+		.name = "osm-l3",
+		.of_match_table = osm_l3_of_match,
+	},
+};
+module_platform_driver(osm_l3_driver);
+
+MODULE_DESCRIPTION("Qualcomm OSM L3 interconnect driver");
+MODULE_LICENSE("GPL v2");

drivers/interconnect/qcom/sdm845.h

···
 #define SDM845_SLAVE_SERVICE_SNOC			128
 #define SDM845_SLAVE_QDSS_STM				129
 #define SDM845_SLAVE_TCU				130
+#define SDM845_MASTER_OSM_L3_APPS			131
+#define SDM845_SLAVE_OSM_L3				132
 
 #endif /* __DRIVERS_INTERCONNECT_QCOM_SDM845_H__ */