[PATCH v2 01/11] usb: typec: ucsi: add PMIC Glink UCSI driver

[Neil Armstrong]

Introduce the UCSI PMIC Glink aux driver that communicates
with the aDSP firmware with the UCSI protocol which handles
the USB-C Port(s) Power Delivery.

The UCSI messaging is necessary on newer Qualcomm SoCs to
provide USB role switch and altmode notifications.

Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
---
 drivers/usb/typec/ucsi/Kconfig      |  10 ++
 drivers/usb/typec/ucsi/Makefile     |   1 +
 drivers/usb/typec/ucsi/ucsi_glink.c | 320 ++++++++++++++++++++++++++++++++++++
 3 files changed, 331 insertions(+)

diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
index 8f9c4b9f31f7..b3bb0191987e 100644
--- a/drivers/usb/typec/ucsi/Kconfig
+++ b/drivers/usb/typec/ucsi/Kconfig
@@ -58,4 +58,14 @@ config UCSI_STM32G0
 	  To compile the driver as a module, choose M here: the module will be
 	  called ucsi_stm32g0.
 
+config UCSI_PMIC_GLINK
+	tristate "UCSI Qualcomm PMIC GLINK Interface Driver"
+	depends on QCOM_PMIC_GLINK
+	help
+	  This driver enables UCSI support on platforms that expose UCSI
+	  interface as PMIC GLINK device.
+
+	  To compile the driver as a module, choose M here: the module will be
+	  called ucsi_glink.
+
 endif
diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
index 480d533d762f..77f09e136956 100644
--- a/drivers/usb/typec/ucsi/Makefile
+++ b/drivers/usb/typec/ucsi/Makefile
@@ -18,3 +18,4 @@ endif
 obj-$(CONFIG_UCSI_ACPI)			+= ucsi_acpi.o
 obj-$(CONFIG_UCSI_CCG)			+= ucsi_ccg.o
 obj-$(CONFIG_UCSI_STM32G0)		+= ucsi_stm32g0.o
+obj-$(CONFIG_UCSI_PMIC_GLINK)		+= ucsi_glink.o
diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c
new file mode 100644
index 000000000000..9123f8a571e7
--- /dev/null
+++ b/drivers/usb/typec/ucsi/ucsi_glink.c
@@ -0,0 +1,320 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2019-2020, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2022-2023, Linaro Ltd
+ */
+#include <linux/auxiliary_bus.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/mutex.h>
+#include <linux/property.h>
+#include <linux/soc/qcom/pdr.h>
+#include <linux/soc/qcom/pmic_glink.h>
+#include "ucsi.h"
+
+#define UCSI_BUF_SIZE                   48
+
+#define MSG_TYPE_REQ_RESP               1
+#define UCSI_BUF_SIZE                   48
+
+#define UC_NOTIFY_RECEIVER_UCSI         0x0
+#define UC_UCSI_READ_BUF_REQ            0x11
+#define UC_UCSI_WRITE_BUF_REQ           0x12
+#define UC_UCSI_USBC_NOTIFY_IND         0x13
+
+struct ucsi_read_buf_req_msg {
+	struct pmic_glink_hdr   hdr;
+};
+
+struct ucsi_read_buf_resp_msg {
+	struct pmic_glink_hdr   hdr;
+	u8                      buf[UCSI_BUF_SIZE];
+	u32                     ret_code;
+};
+
+struct ucsi_write_buf_req_msg {
+	struct pmic_glink_hdr   hdr;
+	u8                      buf[UCSI_BUF_SIZE];
+	u32                     reserved;
+};
+
+struct ucsi_write_buf_resp_msg {
+	struct pmic_glink_hdr   hdr;
+	u32                     ret_code;
+};
+
+struct ucsi_notify_ind_msg {
+	struct pmic_glink_hdr   hdr;
+	u32                     notification;
+	u32                     receiver;
+	u32                     reserved;
+};
+
+struct pmic_glink_ucsi {
+	struct device *dev;
+
+	struct pmic_glink_client *client;
+
+	struct ucsi *ucsi;
+	struct completion read_ack;
+	struct completion write_ack;
+	struct completion sync_ack;
+	bool sync_pending;
+	struct mutex lock;	/* protects concurrent access to PMIC Glink interface */
+
+	int sync_val;
+
+	struct work_struct notify_work;
+	struct work_struct register_work;
+
+	u8 read_buf[UCSI_BUF_SIZE];
+};
+
+static int pmic_glink_ucsi_read(struct ucsi *__ucsi, unsigned int offset,
+				void *val, size_t val_len)
+{
+	struct pmic_glink_ucsi *ucsi = ucsi_get_drvdata(__ucsi);
+	struct ucsi_read_buf_req_msg req = {};
+	unsigned long left;
+	int ret;
+
+	req.hdr.owner = PMIC_GLINK_OWNER_USBC;
+	req.hdr.type = MSG_TYPE_REQ_RESP;
+	req.hdr.opcode = UC_UCSI_READ_BUF_REQ;
+
+	mutex_lock(&ucsi->lock);
+	memset(ucsi->read_buf, 0, sizeof(ucsi->read_buf));
+	reinit_completion(&ucsi->read_ack);
+
+	ret = pmic_glink_send(ucsi->client, &req, sizeof(req));
+	if (ret < 0) {
+		dev_err(ucsi->dev, "failed to send UCSI read request: %d\n", ret);
+		goto out_unlock;
+	}
+
+	left = wait_for_completion_timeout(&ucsi->read_ack, 5 * HZ);
+	if (!left) {
+		dev_err(ucsi->dev, "timeout waiting for UCSI read response\n");
+		ret = -ETIMEDOUT;
+		goto out_unlock;
+	}
+
+	memcpy(val, &ucsi->read_buf[offset], val_len);
+	ret = 0;
+
+out_unlock:
+	mutex_unlock(&ucsi->lock);
+
+	return ret;
+}
+
+static int pmic_glink_ucsi_locked_write(struct pmic_glink_ucsi *ucsi, unsigned int offset,
+					const void *val, size_t val_len)
+{
+	struct ucsi_write_buf_req_msg req = {};
+	unsigned long left;
+	int ret;
+
+	req.hdr.owner = PMIC_GLINK_OWNER_USBC;
+	req.hdr.type = MSG_TYPE_REQ_RESP;
+	req.hdr.opcode = UC_UCSI_WRITE_BUF_REQ;
+	memcpy(&req.buf[offset], val, val_len);
+
+	reinit_completion(&ucsi->write_ack);
+
+	ret = pmic_glink_send(ucsi->client, &req, sizeof(req));
+	if (ret < 0) {
+		dev_err(ucsi->dev, "failed to send UCSI write request: %d\n", ret);
+		return ret;
+	}
+
+	left = wait_for_completion_timeout(&ucsi->write_ack, 5 * HZ);
+	if (!left) {
+		dev_err(ucsi->dev, "timeout waiting for UCSI write response\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int pmic_glink_ucsi_async_write(struct ucsi *__ucsi, unsigned int offset,
+				       const void *val, size_t val_len)
+{
+	struct pmic_glink_ucsi *ucsi = ucsi_get_drvdata(__ucsi);
+	int ret;
+
+	mutex_lock(&ucsi->lock);
+	ret = pmic_glink_ucsi_locked_write(ucsi, offset, val, val_len);
+	mutex_unlock(&ucsi->lock);
+
+	return ret;
+}
+
+static int pmic_glink_ucsi_sync_write(struct ucsi *__ucsi, unsigned int offset,
+				      const void *val, size_t val_len)
+{
+	struct pmic_glink_ucsi *ucsi = ucsi_get_drvdata(__ucsi);
+	unsigned long left;
+	int ret;
+
+	/* TOFIX: Downstream forces recipient to CON when UCSI_GET_ALTERNATE_MODES command */
+
+	mutex_lock(&ucsi->lock);
+	ucsi->sync_val = 0;
+	reinit_completion(&ucsi->sync_ack);
+	ucsi->sync_pending = true;
+	ret = pmic_glink_ucsi_locked_write(ucsi, offset, val, val_len);
+	mutex_unlock(&ucsi->lock);
+
+	left = wait_for_completion_timeout(&ucsi->sync_ack, 5 * HZ);
+	if (!left) {
+		dev_err(ucsi->dev, "timeout waiting for UCSI sync write response\n");
+		ret = -ETIMEDOUT;
+	} else if (ucsi->sync_val) {
+		dev_err(ucsi->dev, "sync write returned: %d\n", ucsi->sync_val);
+	}
+
+	ucsi->sync_pending = false;
+
+	return ret;
+}
+
+static const struct ucsi_operations pmic_glink_ucsi_ops = {
+	.read = pmic_glink_ucsi_read,
+	.sync_write = pmic_glink_ucsi_sync_write,
+	.async_write = pmic_glink_ucsi_async_write
+};
+
+static void pmic_glink_ucsi_read_ack(struct pmic_glink_ucsi *ucsi, const void *data, int len)
+{
+	const struct ucsi_read_buf_resp_msg *resp = data;
+
+	if (resp->ret_code)
+		return;
+
+	memcpy(ucsi->read_buf, resp->buf, UCSI_BUF_SIZE);
+	complete(&ucsi->read_ack);
+}
+
+static void pmic_glink_ucsi_write_ack(struct pmic_glink_ucsi *ucsi, const void *data, int len)
+{
+	const struct ucsi_write_buf_resp_msg *resp = data;
+
+	if (resp->ret_code)
+		return;
+
+	ucsi->sync_val = resp->ret_code;
+	complete(&ucsi->write_ack);
+}
+
+static void pmic_glink_ucsi_notify(struct work_struct *work)
+{
+	struct pmic_glink_ucsi *ucsi = container_of(work, struct pmic_glink_ucsi, notify_work);
+	unsigned int con_num;
+	u32 cci;
+	int ret;
+
+	ret = pmic_glink_ucsi_read(ucsi->ucsi, UCSI_CCI, &cci, sizeof(cci));
+	if (ret) {
+		dev_err(ucsi->dev, "failed to read CCI on notification\n");
+		return;
+	}
+
+	con_num = UCSI_CCI_CONNECTOR(cci);
+	if (con_num)
+		ucsi_connector_change(ucsi->ucsi, con_num);
+
+	if (ucsi->sync_pending && cci & UCSI_CCI_BUSY) {
+		ucsi->sync_val = -EBUSY;
+		complete(&ucsi->sync_ack);
+	} else if (ucsi->sync_pending &&
+		   (cci & (UCSI_CCI_ACK_COMPLETE | UCSI_CCI_COMMAND_COMPLETE))) {
+		complete(&ucsi->sync_ack);
+	}
+}
+
+static void pmic_glink_ucsi_register(struct work_struct *work)
+{
+	struct pmic_glink_ucsi *ucsi = container_of(work, struct pmic_glink_ucsi, register_work);
+
+	ucsi_register(ucsi->ucsi);
+}
+
+static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv)
+{
+	struct pmic_glink_ucsi *ucsi = priv;
+	const struct pmic_glink_hdr *hdr = data;
+
+	switch (hdr->opcode) {
+	case UC_UCSI_READ_BUF_REQ:
+		pmic_glink_ucsi_read_ack(ucsi, data, len);
+		break;
+	case UC_UCSI_WRITE_BUF_REQ:
+		pmic_glink_ucsi_write_ack(ucsi, data, len);
+		break;
+	case UC_UCSI_USBC_NOTIFY_IND:
+		schedule_work(&ucsi->notify_work);
+		break;
+	};
+}
+
+static void pmic_glink_ucsi_pdr_notify(void *priv, int state)
+{
+	struct pmic_glink_ucsi *ucsi = priv;
+
+	if (state == SERVREG_SERVICE_STATE_UP)
+		schedule_work(&ucsi->register_work);
+	else if (state == SERVREG_SERVICE_STATE_DOWN)
+		ucsi_unregister(ucsi->ucsi);
+}
+
+static int pmic_glink_ucsi_probe(struct auxiliary_device *adev,
+				 const struct auxiliary_device_id *id)
+{
+	struct pmic_glink_ucsi *ucsi;
+	struct device *dev = &adev->dev;
+
+	ucsi = devm_kzalloc(dev, sizeof(*ucsi), GFP_KERNEL);
+	if (!ucsi)
+		return -ENOMEM;
+
+	ucsi->dev = dev;
+	dev_set_drvdata(dev, ucsi);
+
+	INIT_WORK(&ucsi->notify_work, pmic_glink_ucsi_notify);
+	INIT_WORK(&ucsi->register_work, pmic_glink_ucsi_register);
+	init_completion(&ucsi->read_ack);
+	init_completion(&ucsi->write_ack);
+	init_completion(&ucsi->sync_ack);
+	mutex_init(&ucsi->lock);
+
+	ucsi->ucsi = ucsi_create(dev, &pmic_glink_ucsi_ops);
+	if (IS_ERR(ucsi->ucsi))
+		return PTR_ERR(ucsi->ucsi);
+
+	ucsi_set_drvdata(ucsi->ucsi, ucsi);
+
+	ucsi->client = devm_pmic_glink_register_client(dev,
+						       PMIC_GLINK_OWNER_USBC,
+						       pmic_glink_ucsi_callback,
+						       pmic_glink_ucsi_pdr_notify,
+						       ucsi);
+	return PTR_ERR_OR_ZERO(ucsi->client);
+}
+
+static const struct auxiliary_device_id pmic_glink_ucsi_id_table[] = {
+	{ .name = "pmic_glink.ucsi", },
+	{},
+};
+MODULE_DEVICE_TABLE(auxiliary, pmic_glink_ucsi_id_table);
+
+static struct auxiliary_driver pmic_glink_ucsi_driver = {
+	.name = "pmic_glink_ucsi",
+	.probe = pmic_glink_ucsi_probe,
+	.id_table = pmic_glink_ucsi_id_table,
+};
+
+module_auxiliary_driver(pmic_glink_ucsi_driver);
+
+MODULE_DESCRIPTION("Qualcomm PMIC GLINK UCSI driver");
+MODULE_LICENSE("GPL");

-- 
2.34.1