[PATCH v3 4/5] interconnect: qcom: Add interconnect SMD over SMD driver

[Georgi Djakov <georgi.djakov@linaro.org>]

On some Qualcomm SoCs, there is a remote processor, which controls some of
the Network-On-Chip interconnect resources. Other CPUs express their needs
by communicating with this processor. Add a driver to handle communication
with this remote processor.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
---

v3:
- New patch.

 drivers/interconnect/qcom/Kconfig   |  9 ++++
 drivers/interconnect/qcom/Makefile  |  2 +
 drivers/interconnect/qcom/smd-rpm.c | 72 +++++++++++++++++++++++++++++
 drivers/interconnect/qcom/smd-rpm.h | 15 ++++++
 4 files changed, 98 insertions(+)
 create mode 100644 drivers/interconnect/qcom/smd-rpm.c
 create mode 100644 drivers/interconnect/qcom/smd-rpm.h

diff --git a/drivers/interconnect/qcom/Kconfig b/drivers/interconnect/qcom/Kconfig
index e76e3e248c41..b0eade1da5d5 100644
--- a/drivers/interconnect/qcom/Kconfig
+++ b/drivers/interconnect/qcom/Kconfig
@@ -9,6 +9,7 @@ config INTERCONNECT_QCOM_QCS404
 	tristate "Qualcomm QCS404 interconnect driver"
 	depends on INTERCONNECT_QCOM
 	depends on QCOM_SMD_RPM || COMPILE_TEST
+	select INTERCONNECT_QCOM_SMD_RPM
 	help
 	  This is a driver for the Qualcomm Network-on-Chip on qcs404-based
 	  platforms.
@@ -20,3 +21,11 @@ config INTERCONNECT_QCOM_SDM845
 	help
 	  This is a driver for the Qualcomm Network-on-Chip on sdm845-based
 	  platforms.
+
+config INTERCONNECT_QCOM_SMD_RPM
+	tristate "Qualcomm SMD RPM interconnect driver"
+	depends on INTERCONNECT_QCOM
+	depends on QCOM_SMD_RPM || COMPILE_TEST
+	help
+	  This is a driver for communicating interconnect related configuration
+	  details with a remote processor (RPM) on Qualcomm platforms.
diff --git a/drivers/interconnect/qcom/Makefile b/drivers/interconnect/qcom/Makefile
index 059ff325ee6c..67dafb783dec 100644
--- a/drivers/interconnect/qcom/Makefile
+++ b/drivers/interconnect/qcom/Makefile
@@ -2,6 +2,8 @@
 
 qnoc-qcs404-objs			:= qcs404.o
 qnoc-sdm845-objs			:= sdm845.o
+icc-smd-rpm-objs			:= smd-rpm.o
 
 obj-$(CONFIG_INTERCONNECT_QCOM_QCS404) += qnoc-qcs404.o
 obj-$(CONFIG_INTERCONNECT_QCOM_SDM845) += qnoc-sdm845.o
+obj-$(CONFIG_INTERCONNECT_QCOM_SMD_RPM) += icc-smd-rpm.o
diff --git a/drivers/interconnect/qcom/smd-rpm.c b/drivers/interconnect/qcom/smd-rpm.c
new file mode 100644
index 000000000000..af22c0a293e6
--- /dev/null
+++ b/drivers/interconnect/qcom/smd-rpm.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RPM over SMD communication wrapper for interconnects
+ *
+ * Copyright (C) 2019 Linaro Ltd
+ * Author: Georgi Djakov <georgi.djakov@linaro.org>
+ */
+
+#include <linux/interconnect-provider.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/soc/qcom/smd-rpm.h>
+
+#include "smd-rpm.h"
+
+#define RPM_KEY_BW		0x00007762
+
+static struct qcom_smd_rpm *icc_smd_rpm;
+
+struct icc_rpm_smd_req {
+	__le32 key;
+	__le32 nbytes;
+	__le32 value;
+};
+
+bool qcom_icc_rpm_smd_available(void)
+{
+	if (!icc_smd_rpm)
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(qcom_icc_rpm_smd_available);
+
+int qcom_icc_rpm_smd_send(int ctx, int rsc_type, int id, u32 val)
+{
+	struct icc_rpm_smd_req req = {
+		.key = cpu_to_le32(RPM_KEY_BW),
+		.nbytes = cpu_to_le32(sizeof(u32)),
+		.value = cpu_to_le32(val),
+	};
+
+	return qcom_rpm_smd_write(icc_smd_rpm, ctx, rsc_type, id, &req,
+				  sizeof(req));
+}
+EXPORT_SYMBOL_GPL(qcom_icc_rpm_smd_send);
+
+static int qcom_icc_rpm_smd_probe(struct platform_device *pdev)
+{
+	icc_smd_rpm = dev_get_drvdata(pdev->dev.parent);
+
+	if (!icc_smd_rpm) {
+		dev_err(&pdev->dev, "unable to retrieve handle to RPM\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static struct platform_driver qcom_interconnect_rpm_smd_driver = {
+	.driver = {
+		.name		= "icc_smd_rpm",
+	},
+	.probe = qcom_icc_rpm_smd_probe,
+};
+module_platform_driver(qcom_interconnect_rpm_smd_driver);
+MODULE_AUTHOR("Georgi Djakov <georgi.djakov@linaro.org>");
+MODULE_DESCRIPTION("Qualcomm SMD RPM interconnect proxy driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:icc_smd_rpm");
diff --git a/drivers/interconnect/qcom/smd-rpm.h b/drivers/interconnect/qcom/smd-rpm.h
new file mode 100644
index 000000000000..ca9d0327b8ac
--- /dev/null
+++ b/drivers/interconnect/qcom/smd-rpm.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2019, Linaro Ltd.
+ * Author: Georgi Djakov <georgi.djakov@linaro.org>
+ */
+
+#ifndef __DRIVERS_INTERCONNECT_QCOM_SMD_RPM_H
+#define __DRIVERS_INTERCONNECT_QCOM_SMD_RPM_H
+
+#include <linux/soc/qcom/smd-rpm.h>
+
+bool qcom_icc_rpm_smd_available(void);
+int qcom_icc_rpm_smd_send(int ctx, int rsc_type, int id, u32 val);
+
+#endif