[RFC V6 2/8] firmware: arm_scmi: vendors: Add QCOM SCMI Generic Extensions

[Sibi Sankar <sibi.sankar@oss.qualcomm.com>]

The QCOM SCMI Generic Extensions Protocol provides a generic way of
exposing a number of Qualcomm SoC specific features (like memory bus
scaling) through a mixture of pre-determined algorithm strings and
param_id pairs hosted on the SCMI controller.

Co-developed-by: Shivnandan Kumar <quic_kshivnan@quicinc.com>
Signed-off-by: Shivnandan Kumar <quic_kshivnan@quicinc.com>
Co-developed-by: Ramakrishna Gottimukkula <quic_rgottimu@quicinc.com>
Signed-off-by: Ramakrishna Gottimukkula <quic_rgottimu@quicinc.com>
Co-developed-by: Amir Vajid <avajid@quicinc.com>
Signed-off-by: Amir Vajid <avajid@quicinc.com>
Signed-off-by: Sibi Sankar <sibi.sankar@oss.qualcomm.com>
---

@Sudeep/@Christian, Just moving the series back in RFC mode to get feedback
on the devfreq part of the series. Will add a lot more documentation in the
next re-spin, so definitely not ignoring your earlier comments :).

 drivers/firmware/arm_scmi/Kconfig             |   1 +
 drivers/firmware/arm_scmi/Makefile            |   1 +
 .../firmware/arm_scmi/vendors/qcom/Kconfig    |  15 ++
 .../firmware/arm_scmi/vendors/qcom/Makefile   |   2 +
 .../arm_scmi/vendors/qcom/qcom-generic-ext.c  | 135 ++++++++++++++++++
 include/linux/scmi_qcom_protocol.h            |  37 +++++
 6 files changed, 191 insertions(+)
 create mode 100644 drivers/firmware/arm_scmi/vendors/qcom/Kconfig
 create mode 100644 drivers/firmware/arm_scmi/vendors/qcom/Makefile
 create mode 100644 drivers/firmware/arm_scmi/vendors/qcom/qcom-generic-ext.c
 create mode 100644 include/linux/scmi_qcom_protocol.h

diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig
index e3fb36825978..a52f4d1b8b2c 100644
--- a/drivers/firmware/arm_scmi/Kconfig
+++ b/drivers/firmware/arm_scmi/Kconfig
@@ -84,6 +84,7 @@ config ARM_SCMI_QUIRKS
 
 source "drivers/firmware/arm_scmi/transports/Kconfig"
 source "drivers/firmware/arm_scmi/vendors/imx/Kconfig"
+source "drivers/firmware/arm_scmi/vendors/qcom/Kconfig"
 
 endif #ARM_SCMI_PROTOCOL
 
diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
index 780cd62b2f78..5a0e003c2477 100644
--- a/drivers/firmware/arm_scmi/Makefile
+++ b/drivers/firmware/arm_scmi/Makefile
@@ -13,6 +13,7 @@ scmi-module-objs := $(scmi-driver-y) $(scmi-protocols-y) $(scmi-transport-y)
 
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += transports/
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += vendors/imx/
+obj-$(CONFIG_ARM_SCMI_PROTOCOL) += vendors/qcom/
 
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-core.o
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-module.o
diff --git a/drivers/firmware/arm_scmi/vendors/qcom/Kconfig b/drivers/firmware/arm_scmi/vendors/qcom/Kconfig
new file mode 100644
index 000000000000..5dd9e8a6b75f
--- /dev/null
+++ b/drivers/firmware/arm_scmi/vendors/qcom/Kconfig
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "ARM SCMI QCOM Vendor Protocols"
+
+config QCOM_SCMI_GENERIC_EXT
+	tristate "Qualcomm Technologies, Inc. Qcom SCMI vendor Protocol"
+	depends on ARM_SCMI_PROTOCOL || COMPILE_TEST
+	help
+	  The QCOM SCMI vendor protocol provides a generic way of exposing
+	  a number of Qualcomm SoC specific features (like memory bus scaling)
+	  through a mixture of pre-determined algorithm strings and param_id
+	  pairs hosted on the SCMI controller.
+
+	  This driver defines/documents the message ID's used for this
+	  communication and also exposes the operations used by the clients.
+endmenu
diff --git a/drivers/firmware/arm_scmi/vendors/qcom/Makefile b/drivers/firmware/arm_scmi/vendors/qcom/Makefile
new file mode 100644
index 000000000000..6b98fabbebb8
--- /dev/null
+++ b/drivers/firmware/arm_scmi/vendors/qcom/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_QCOM_SCMI_GENERIC_EXT) += qcom-generic-ext.o
diff --git a/drivers/firmware/arm_scmi/vendors/qcom/qcom-generic-ext.c b/drivers/firmware/arm_scmi/vendors/qcom/qcom-generic-ext.c
new file mode 100644
index 000000000000..4f9eba8ff4bd
--- /dev/null
+++ b/drivers/firmware/arm_scmi/vendors/qcom/qcom-generic-ext.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/scmi_qcom_protocol.h>
+
+#include "../../common.h"
+
+/**
+ * enum qcom_generic_ext_protocol_cmd - vendor specific commands supported by SCMI Qualcomm
+ *                                      generic vendor protocol.
+ *
+ * This protocol is intended as a generic way of exposing a number of Qualcomm SoC
+ * specific features through a mixture of pre-determined algorithm string and param_id
+ * pairs hosted on the SCMI controller.
+ *
+ * The QCOM SCMI Vendor Protocol has the protocol id as 0x80 and vendor id set to
+ * Qualcomm and the supported version is set to 0x10000. The PROTOCOL_VERSION command
+ * returns version 1.0.
+ *
+ * @QCOM_SCMI_SET_PARAM: is used to set the parameter of a specific algo_str hosted on
+ *			 QCOM SCMI Vendor Protocol. The tx len depends on the algo_str used.
+ * @QCOM_SCMI_GET_PARAM: is used to get parameter information of a specific algo_str
+ *			 hosted on QCOM SCMI Vendor Protocol. The tx and rx len depends
+ *			 on the algo_str used.
+ * @QCOM_SCMI_START_ACTIVITY: is used to start the activity performed by the algo_str.
+ * @QCOM_SCMI_STOP_ACTIVITY: is used to stop a pre-existing activity performed by the algo_str.
+ */
+enum qcom_generic_ext_protocol_cmd {
+	QCOM_SCMI_SET_PARAM = 0x10,
+	QCOM_SCMI_GET_PARAM = 0x11,
+	QCOM_SCMI_START_ACTIVITY = 0x12,
+	QCOM_SCMI_STOP_ACTIVITY = 0x13,
+};
+
+/**
+ * struct qcom_scmi_msg - represents the various parameters to be populated
+ *                        for using the QCOM SCMI Vendor Protocol
+ *
+ * @ext_id: reserved, must be zero
+ * @algo_low: lower 32 bits of the algo_str
+ * @algo_high: upper 32 bits of the algo_str
+ * @param_id: serves as token message id to the specific algo_str
+ * @buf: serves as the payload to the specified param_id and algo_str pair
+ */
+struct qcom_scmi_msg {
+	__le32 ext_id;
+	__le32 algo_low;
+	__le32 algo_high;
+	__le32 param_id;
+	__le32 buf[];
+};
+
+static int qcom_scmi_common_xfer(const struct scmi_protocol_handle *ph,
+				 enum qcom_generic_ext_protocol_cmd cmd_id, void *buf,
+				 size_t buf_len, u64 algo_str, u32 param_id, size_t rx_size)
+{
+	struct scmi_xfer *t;
+	struct qcom_scmi_msg *msg;
+	int ret;
+
+	ret = ph->xops->xfer_get_init(ph, cmd_id, buf_len + sizeof(*msg), rx_size, &t);
+	if (ret)
+		return ret;
+
+	msg = t->tx.buf;
+	msg->algo_low = cpu_to_le32(lower_32_bits(algo_str));
+	msg->algo_high = cpu_to_le32(upper_32_bits(algo_str));
+	msg->param_id = cpu_to_le32(param_id);
+	memcpy(msg->buf, buf, buf_len);
+
+	ret = ph->xops->do_xfer(ph, t);
+	if (!ret && rx_size)
+		memcpy(buf, t->rx.buf, t->rx.len);
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
+static int qcom_scmi_set_param(const struct scmi_protocol_handle *ph, void *buf, size_t buf_len,
+			       u64 algo_str, u32 param_id)
+{
+	return qcom_scmi_common_xfer(ph, QCOM_SCMI_SET_PARAM, buf, buf_len, algo_str,
+				     param_id, 0);
+}
+
+static int qcom_scmi_get_param(const struct scmi_protocol_handle *ph, void *buf, size_t buf_len,
+			       u64 algo_str, u32 param_id, size_t rx_size)
+{
+	return qcom_scmi_common_xfer(ph, QCOM_SCMI_GET_PARAM, buf, buf_len, algo_str,
+				     param_id, rx_size);
+}
+
+static int qcom_scmi_start_activity(const struct scmi_protocol_handle *ph, void *buf,
+				    size_t buf_len, u64 algo_str, u32 param_id)
+{
+	return qcom_scmi_common_xfer(ph, QCOM_SCMI_START_ACTIVITY, buf, buf_len, algo_str,
+				     param_id, 0);
+}
+
+static int qcom_scmi_stop_activity(const struct scmi_protocol_handle *ph, void *buf,
+				   size_t buf_len, u64 algo_str, u32 param_id)
+{
+	return qcom_scmi_common_xfer(ph, QCOM_SCMI_STOP_ACTIVITY, buf, buf_len, algo_str,
+				     param_id, 0);
+}
+
+static struct qcom_generic_ext_ops qcom_proto_ops = {
+	.set_param = qcom_scmi_set_param,
+	.get_param = qcom_scmi_get_param,
+	.start_activity = qcom_scmi_start_activity,
+	.stop_activity = qcom_scmi_stop_activity,
+};
+
+static int qcom_generic_ext_protocol_init(const struct scmi_protocol_handle *ph)
+{
+	dev_dbg(ph->dev, "QCOM Generic Vendor Version %d.%d\n",
+		PROTOCOL_REV_MAJOR(ph->version), PROTOCOL_REV_MINOR(ph->version));
+
+	return 0;
+}
+
+static const struct scmi_protocol qcom_generic_ext = {
+	.id = SCMI_PROTOCOL_QCOM_GENERIC,
+	.owner = THIS_MODULE,
+	.instance_init = &qcom_generic_ext_protocol_init,
+	.ops = &qcom_proto_ops,
+	.vendor_id = "Qualcomm",
+	.supported_version = 0x10000,
+};
+module_scmi_protocol(qcom_generic_ext);
+
+MODULE_DESCRIPTION("QCOM SCMI Generic Vendor protocol");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/scmi_qcom_protocol.h b/include/linux/scmi_qcom_protocol.h
new file mode 100644
index 000000000000..465b2522ca29
--- /dev/null
+++ b/include/linux/scmi_qcom_protocol.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * SCMI Message Protocol driver QCOM extension header
+ *
+ * Copyright (c) 2024, Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _LINUX_SCMI_QCOM_PROTOCOL_H
+#define _LINUX_SCMI_QCOM_PROTOCOL_H
+
+#include <linux/types.h>
+
+#define SCMI_PROTOCOL_QCOM_GENERIC    0x80
+
+struct scmi_protocol_handle;
+
+/**
+ * struct qcom_generic_ext_ops - represents the various operations provided
+ *				 by QCOM Generic Vendor Protocol
+ *
+ * @set_param: set parameter specified by param_id and algo_str pair.
+ * @get_param: retrieve parameter specified by param_id and algo_str pair.
+ * @start_activity: initiate a specific activity defined by algo_str.
+ * @stop_activity: halt previously initiated activity defined by algo_str.
+ */
+struct qcom_generic_ext_ops {
+	int (*set_param)(const struct scmi_protocol_handle *ph, void *buf, size_t buf_len,
+			 u64 algo_str, u32 param_id);
+	int (*get_param)(const struct scmi_protocol_handle *ph, void *buf, size_t buf_len,
+			 u64 algo_str, u32 param_id, size_t rx_size);
+	int (*start_activity)(const struct scmi_protocol_handle *ph, void *buf, size_t buf_len,
+			      u64 algo_str, u32 param_id);
+	int (*stop_activity)(const struct scmi_protocol_handle *ph, void *buf, size_t buf_len,
+			     u64 algo_str, u32 param_id);
+};
+
+#endif /* _LINUX_SCMI_QCOM_PROTOCOL_H */
-- 
2.34.1