[v9,5/8] interconnect: qcom: Add RPM communication

Commit Message

Georgi Djakov Aug. 31, 2018, 2:01 p.m. UTC

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 <[e-mail]>
Reviewed-by: Evan Green <[e-mail]>
---
 .../bindings/interconnect/qcom-smd.txt        | 32 +++++++
 drivers/interconnect/qcom/Kconfig             | 13 +++
 drivers/interconnect/qcom/Makefile            |  5 +
 drivers/interconnect/qcom/smd-rpm.c           | 91 +++++++++++++++++++
 drivers/interconnect/qcom/smd-rpm.h           | 15 +++
 5 files changed, 156 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interconnect/qcom-smd.txt
 create mode 100644 drivers/interconnect/qcom/Kconfig
 create mode 100644 drivers/interconnect/qcom/Makefile
 create mode 100644 drivers/interconnect/qcom/smd-rpm.c
 create mode 100644 drivers/interconnect/qcom/smd-rpm.h

Comments

Rob Herring (Arm) Sept. 25, 2018, 6:17 p.m. UTC | #1

On Fri, Aug 31, 2018 at 05:01:48PM +0300, Georgi Djakov wrote:
> 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.

I don't think you should have a binding nor a separate driver for this. 
It's not actually an interconnect provider, so it doesn't belong in 
bindings/interconnect. And it just looks like abuse of DT to instantiate 
some driver.

All the driver amounts to is a 1 function wrapper for RPM_KEY_BW 
messages. Can't this be part of the parent?

Rob

Georgi Djakov Oct. 2, 2018, 11:02 a.m. UTC | #2

Hi Rob,

On 09/25/2018 09:17 PM, Rob Herring wrote:
> On Fri, Aug 31, 2018 at 05:01:48PM +0300, Georgi Djakov wrote:
>> 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.
> 
> I don't think you should have a binding nor a separate driver for this. 
> It's not actually an interconnect provider, so it doesn't belong in 
> bindings/interconnect. And it just looks like abuse of DT to instantiate 
> some driver.

The idea of this binding here is to represent the remote processor, that
is also in control of some of the shared interconnect paths. The
bandwidth needs of the DSPs and modem are also reported to this remote
processor. It also takes over some of the bandwidth management while the
application CPU is powered down. So yes, it is also a kind of an
interconnect provider, so IMO it should be in DT.
We already have similar DT sub-nodes for remote regulator and clock
resources and this is just adding another sub-node for the interconnect
bandwidth related subsystem.

This, together with each separate NoC hardware block (in patch 6/8) are
building up the whole topology. The configuration of interconnect paths
consists of a combination of register writes, clock scaling and sending
a message to the remote processor.

> All the driver amounts to is a 1 function wrapper for RPM_KEY_BW 
> messages. Can't this be part of the parent?

I am re-using this part for other SoCs and have separated it to avoid
duplication.

Thanks,
Georgi

Patch

diff --git a/Documentation/devicetree/bindings/interconnect/qcom-smd.txt b/Documentation/devicetree/bindings/interconnect/qcom-smd.txt
new file mode 100644
index 000000000000..2325167f6eaf
--- /dev/null
+++ b/Documentation/devicetree/bindings/interconnect/qcom-smd.txt
@@ -0,0 +1,32 @@ 
+Qualcomm SMD-RPM interconnect driver binding
+------------------------------------------------
+The RPM (Resource Power Manager) is a dedicated hardware engine
+for managing the shared SoC resources in order to keep the lowest
+power profile. It communicates with other hardware subsystems via
+the shared memory driver (SMD) back-end and accepts requests for
+various resources.
+
+Required properties :
+- compatible : shall contain only one of the following:
+			"qcom,interconnect-smd-rpm"
+
+Example:
+	smd {
+		compatible = "qcom,smd";
+
+		rpm {
+			interrupts = <GIC_SPI 168 IRQ_TYPE_EDGE_RISING>;
+			qcom,ipc = <&apcs 8 0>;
+			qcom,smd-edge = <15>;
+
+			rpm_requests {
+				compatible = "qcom,rpm-msm8916";
+				qcom,smd-channels = "rpm_requests";
+
+				interconnect-smd-rpm {
+					compatible = "qcom,interconnect-smd-rpm";
+				};
+
+			};
+		};
+	};
diff --git a/drivers/interconnect/qcom/Kconfig b/drivers/interconnect/qcom/Kconfig
new file mode 100644
index 000000000000..6146552fac86
--- /dev/null
+++ b/drivers/interconnect/qcom/Kconfig
@@ -0,0 +1,13 @@ 
+config INTERCONNECT_QCOM
+	bool "Qualcomm Network-on-Chip interconnect drivers"
+	depends on ARCH_QCOM
+	help
+	  Support for Qualcomm's Network-on-Chip interconnect hardware.
+
+config INTERCONNECT_QCOM_SMD_RPM
+	tristate "Qualcomm SMD RPM interconnect driver"
+	depends on INTERCONNECT_QCOM
+	depends on QCOM_SMD_RPM
+	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
new file mode 100644
index 000000000000..f4477ad22ba2
--- /dev/null
+++ b/drivers/interconnect/qcom/Makefile
@@ -0,0 +1,5 @@ 
+# SPDX-License-Identifier: GPL-2.0
+
+qnoc-smd-rpm-objs			:= smd-rpm.o
+
+obj-$(CONFIG_INTERCONNECT_QCOM_SMD_RPM) += qnoc-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..48b7a2a6eb84
--- /dev/null
+++ b/drivers/interconnect/qcom/smd-rpm.c
@@ -0,0 +1,91 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RPM over SMD communication wrapper for interconnects
+ *
+ * Copyright (C) 2018 Linaro Ltd
+ * Author: Georgi Djakov <[e-mail]>
+ */
+
+#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_icc_rpm {
+	struct qcom_smd_rpm *rpm;
+} icc_rpm_smd;
+
+struct icc_rpm_smd_req {
+	__le32 key;
+	__le32 nbytes;
+	__le32 value;
+};
+
+bool qcom_icc_rpm_smd_available(void)
+{
+	if (!icc_rpm_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_rpm_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_rpm_smd.rpm = dev_get_drvdata(pdev->dev.parent);
+	if (!icc_rpm_smd.rpm) {
+		dev_err(&pdev->dev, "unable to retrieve handle to RPM\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id qcom_icc_rpm_smd_dt_match[] = {
+	{ .compatible = "qcom,interconnect-smd-rpm", },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, qcom_icc_rpm_smd_dt_match);
+
+static struct platform_driver qcom_interconnect_rpm_smd_driver = {
+	.driver = {
+		.name		= "qcom-interconnect-smd-rpm",
+		.of_match_table	= qcom_icc_rpm_smd_dt_match,
+	},
+	.probe = qcom_icc_rpm_smd_probe,
+};
+
+static int __init rpm_smd_interconnect_init(void)
+{
+	return platform_driver_register(&qcom_interconnect_rpm_smd_driver);
+}
+subsys_initcall(rpm_smd_interconnect_init);
+
+static void __exit rpm_smd_interconnect_exit(void)
+{
+	platform_driver_unregister(&qcom_interconnect_rpm_smd_driver);
+}
+module_exit(rpm_smd_interconnect_exit)
+
+MODULE_AUTHOR("Georgi Djakov <[e-mail]>");
+MODULE_DESCRIPTION("Qualcomm SMD RPM interconnect driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/interconnect/qcom/smd-rpm.h b/drivers/interconnect/qcom/smd-rpm.h
new file mode 100644
index 000000000000..11c280eb86dc
--- /dev/null
+++ b/drivers/interconnect/qcom/smd-rpm.h
@@ -0,0 +1,15 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2018, Linaro Ltd.
+ * Author: Georgi Djakov <[e-mail]>
+ */
+
+#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