interconnect: Add generic on-chip interconnect API

This patch introduces a new API to get requirements and configure the
interconnect buses across the entire chipset to fit with the current
demand.

The API is using a consumer/provider-based model, where the providers are
the interconnect buses and the consumers could be various drivers.
The consumers request interconnect resources (path) between endpoints and
set the desired constraints on this data flow path. The providers receive
requests from consumers and aggregate these requests for all master-slave
pairs on that path. Then the providers configure each node along the path
to support a bandwidth that satisfies all bandwidth requests that cross
through that node. The topology could be complicated and multi-tiered and
is SoC specific.

Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/include/linux/interconnect.h b/include/linux/interconnect.h
new file mode 100644
index 000000000000..c331afb3a2c8
--- /dev/null
+++ b/include/linux/interconnect.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2018-2019, Linaro Ltd.
+ * Author: Georgi Djakov <georgi.djakov@linaro.org>
+ */
+
+#ifndef __LINUX_INTERCONNECT_H
+#define __LINUX_INTERCONNECT_H
+
+#include <linux/mutex.h>
+#include <linux/types.h>
+
+/* macros for converting to icc units */
+#define Bps_to_icc(x)	((x) / 1000)
+#define kBps_to_icc(x)	(x)
+#define MBps_to_icc(x)	((x) * 1000)
+#define GBps_to_icc(x)	((x) * 1000 * 1000)
+#define bps_to_icc(x)	(1)
+#define kbps_to_icc(x)	((x) / 8 + ((x) % 8 ? 1 : 0))
+#define Mbps_to_icc(x)	((x) * 1000 / 8)
+#define Gbps_to_icc(x)	((x) * 1000 * 1000 / 8)
+
+struct icc_path;
+struct device;
+
+#if IS_ENABLED(CONFIG_INTERCONNECT)
+
+struct icc_path *icc_get(struct device *dev, const int src_id,
+			 const int dst_id);
+void icc_put(struct icc_path *path);
+int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw);
+
+#else
+
+static inline struct icc_path *icc_get(struct device *dev, const int src_id,
+				       const int dst_id)
+{
+	return NULL;
+}
+
+static inline void icc_put(struct icc_path *path)
+{
+}
+
+static inline int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw)
+{
+	return 0;
+}
+
+#endif /* CONFIG_INTERCONNECT */
+
+#endif /* __LINUX_INTERCONNECT_H */