soc: qcom: add ADSP PDCharger ULOG driver

The Qualcomm PMIC PDCharger ULOG driver provides access to logs of
the ADSP firmware PDCharger module in charge of Battery and Power
Delivery on modern systems.

Implement trace events as a simple rpmsg driver with an 1s interval
to retrieve the messages.

The interface allows filtering the messages by subsystem and priority
level, this could be implemented later on.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20230908-topic-sm8550-upstream-pdcharge-ulog-v1-1-d1b16b02ced2@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

drivers/soc/qcom/Kconfig

@@ -77,6 +77,18 @@ config QCOM_PDR_HELPERS
 	select QCOM_QMI_HELPERS
 	depends on NET
 
+config QCOM_PMIC_PDCHARGER_ULOG
+	tristate "Qualcomm PMIC PDCharger ULOG driver"
+	depends on RPMSG
+	depends on EVENT_TRACING
+	help
+	  The Qualcomm PMIC PDCharger ULOG driver provides access to logs of
+	  the ADSP firmware PDCharger module in charge of Battery and Power
+	  Delivery on modern systems.
+
+	  Say yes here to support PDCharger ULOG event tracing on modern
+	  Qualcomm platforms.
+
 config QCOM_PMIC_GLINK
 	tristate "Qualcomm PMIC GLINK driver"
 	depends on RPMSG

drivers/soc/qcom/Makefile

@@ -9,6 +9,7 @@ obj-$(CONFIG_QCOM_OCMEM)	+= ocmem.o
 obj-$(CONFIG_QCOM_PDR_HELPERS)	+= pdr_interface.o
 obj-$(CONFIG_QCOM_PMIC_GLINK)	+= pmic_glink.o
 obj-$(CONFIG_QCOM_PMIC_GLINK)	+= pmic_glink_altmode.o
+obj-$(CONFIG_QCOM_PMIC_PDCHARGER_ULOG)	+= pmic_pdcharger_ulog.o
 obj-$(CONFIG_QCOM_QMI_HELPERS)	+= qmi_helpers.o
 qmi_helpers-y	+= qmi_encdec.o qmi_interface.o
 obj-$(CONFIG_QCOM_RAMP_CTRL)	+= ramp_controller.o

drivers/soc/qcom/pmic_pdcharger_ulog.c

@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2019-2022, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2023, Linaro Ltd
+ */
+#include <linux/of_device.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/rpmsg.h>
+#include <linux/slab.h>
+#include <linux/soc/qcom/pdr.h>
+#include <linux/debugfs.h>
+
+#define CREATE_TRACE_POINTS
+#include "pmic_pdcharger_ulog.h"
+
+#define MSG_OWNER_CHG_ULOG		32778
+#define MSG_TYPE_REQ_RESP		1
+
+#define GET_CHG_ULOG_REQ		0x18
+#define SET_CHG_ULOG_PROP_REQ		0x19
+
+#define LOG_DEFAULT_TIME_MS		1000
+
+#define MAX_ULOG_SIZE			8192
+
+struct pmic_pdcharger_ulog_hdr {
+	__le32 owner;
+	__le32 type;
+	__le32 opcode;
+};
+
+struct pmic_pdcharger_ulog {
+	struct rpmsg_device *rpdev;
+	struct delayed_work ulog_work;
+};
+
+struct get_ulog_req_msg {
+	struct pmic_pdcharger_ulog_hdr	hdr;
+	u32				log_size;
+};
+
+struct get_ulog_resp_msg {
+	struct pmic_pdcharger_ulog_hdr	hdr;
+	u8				buf[MAX_ULOG_SIZE];
+};
+
+static int pmic_pdcharger_ulog_write_async(struct pmic_pdcharger_ulog *pg, void *data, size_t len)
+{
+	return rpmsg_send(pg->rpdev->ept, data, len);
+}
+
+static int pmic_pdcharger_ulog_request(struct pmic_pdcharger_ulog *pg)
+{
+	struct get_ulog_req_msg req_msg = {
+		.hdr = {
+			.owner = MSG_OWNER_CHG_ULOG,
+			.type = MSG_TYPE_REQ_RESP,
+			.opcode = GET_CHG_ULOG_REQ
+		},
+		.log_size = MAX_ULOG_SIZE
+	};
+
+	return pmic_pdcharger_ulog_write_async(pg, &req_msg, sizeof(req_msg));
+}
+
+static void pmic_pdcharger_ulog_work(struct work_struct *work)
+{
+	struct pmic_pdcharger_ulog *pg = container_of(work, struct pmic_pdcharger_ulog,
+						      ulog_work.work);
+	int rc;
+
+	rc = pmic_pdcharger_ulog_request(pg);
+	if (rc) {
+		dev_err(&pg->rpdev->dev, "Error requesting ulog, rc=%d\n", rc);
+		return;
+	}
+}
+
+static void pmic_pdcharger_ulog_handle_message(struct pmic_pdcharger_ulog *pg,
+					       struct get_ulog_resp_msg *resp_msg,
+					       size_t len)
+{
+	char *token, *buf = resp_msg->buf;
+
+	if (len != sizeof(*resp_msg)) {
+		dev_err(&pg->rpdev->dev, "Expected data length: %zu, received: %zu\n",
+			sizeof(*resp_msg), len);
+		return;
+	}
+
+	buf[MAX_ULOG_SIZE - 1] = '\0';
+
+	do {
+		token = strsep((char **)&buf, "\n");
+		if (token && strlen(token))
+			trace_pmic_pdcharger_ulog_msg(token);
+	} while (token);
+}
+
+static int pmic_pdcharger_ulog_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
+					      int len, void *priv, u32 addr)
+{
+	struct pmic_pdcharger_ulog *pg = dev_get_drvdata(&rpdev->dev);
+	struct pmic_pdcharger_ulog_hdr *hdr = data;
+	u32 opcode;
+
+	opcode = le32_to_cpu(hdr->opcode);
+
+	switch (opcode) {
+	case GET_CHG_ULOG_REQ:
+		schedule_delayed_work(&pg->ulog_work, msecs_to_jiffies(LOG_DEFAULT_TIME_MS));
+		pmic_pdcharger_ulog_handle_message(pg, data, len);
+		break;
+	default:
+		dev_err(&pg->rpdev->dev, "Unknown opcode %u\n", opcode);
+		break;
+	}
+
+	return 0;
+}
+
+static int pmic_pdcharger_ulog_rpmsg_probe(struct rpmsg_device *rpdev)
+{
+	struct pmic_pdcharger_ulog *pg;
+	struct device *dev = &rpdev->dev;
+
+	pg = devm_kzalloc(dev, sizeof(*pg), GFP_KERNEL);
+	if (!pg)
+		return -ENOMEM;
+
+	pg->rpdev = rpdev;
+	INIT_DELAYED_WORK(&pg->ulog_work, pmic_pdcharger_ulog_work);
+
+	dev_set_drvdata(dev, pg);
+
+	pmic_pdcharger_ulog_request(pg);
+
+	return 0;
+}
+
+static void pmic_pdcharger_ulog_rpmsg_remove(struct rpmsg_device *rpdev)
+{
+	struct pmic_pdcharger_ulog *pg = dev_get_drvdata(&rpdev->dev);
+
+	cancel_delayed_work_sync(&pg->ulog_work);
+}
+
+static const struct rpmsg_device_id pmic_pdcharger_ulog_rpmsg_id_match[] = {
+	{ "PMIC_LOGS_ADSP_APPS" },
+	{}
+};
+
+static struct rpmsg_driver pmic_pdcharger_ulog_rpmsg_driver = {
+	.probe = pmic_pdcharger_ulog_rpmsg_probe,
+	.remove = pmic_pdcharger_ulog_rpmsg_remove,
+	.callback = pmic_pdcharger_ulog_rpmsg_callback,
+	.id_table = pmic_pdcharger_ulog_rpmsg_id_match,
+	.drv  = {
+		.name  = "qcom_pmic_pdcharger_ulog_rpmsg",
+	},
+};
+
+module_rpmsg_driver(pmic_pdcharger_ulog_rpmsg_driver);
+MODULE_DESCRIPTION("Qualcomm PMIC ChargerPD ULOG driver");
+MODULE_LICENSE("GPL");

drivers/soc/qcom/pmic_pdcharger_ulog.h

@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2023, Linaro Ltd
+ */
+
+#if !defined(_TRACE_PMIC_PDCHARGER_ULOG_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PMIC_PDCHARGER_ULOG_H
+
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM pmic_pdcharger_ulog
+
+TRACE_EVENT(pmic_pdcharger_ulog_msg,
+	TP_PROTO(char *msg),
+	TP_ARGS(msg),
+	TP_STRUCT__entry(
+		__string(msg, msg)
+	),
+	TP_fast_assign(
+		__assign_str(msg, msg);
+	),
+	TP_printk("%s", __get_str(msg))
+);
+
+#endif /* _TRACE_PMIC_PDCHARGER_ULOG_H */
+
+/* This part must be outside protection */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE pmic_pdcharger_ulog
+
+#include <trace/define_trace.h>