[PATCH v5 3/8] usb: typec: ucsi: Implement ChromeOS UCSI driver

Łukasz Bartosik
2024-09-03T16:30:42Z

From: Pavan Holla <pholla@chromium.org>

Implementation of a UCSI transport driver for ChromeOS.
This driver will be loaded if the ChromeOS EC implements a PPM.

Signed-off-by: Pavan Holla <pholla@chromium.org>
Co-developed-by: Łukasz Bartosik <ukaszb@chromium.org>
Signed-off-by: Łukasz Bartosik <ukaszb@chromium.org>
---
MAINTAINERS | 7 +
drivers/usb/typec/ucsi/Kconfig | 13 ++
drivers/usb/typec/ucsi/Makefile | 1 +
drivers/usb/typec/ucsi/cros_ec_ucsi.c | 278 ++++++++++++++++++++++++++
4 files changed, 299 insertions(+)
create mode 100644 drivers/usb/typec/ucsi/cros_ec_ucsi.c

diff --git a/MAINTAINERS b/MAINTAINERS
index fe83ba7194ea..8c030ea0b503 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5300,6 +5300,13 @@ L: chrome-platform@lists.linux.dev
S: Maintained
F: drivers/watchdog/cros_ec_wdt.c

+CHROMEOS UCSI DRIVER
+M: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
+M: Łukasz Bartosik <ukaszb@chromium.org>
+L: chrome-platform@lists.linux.dev
+S: Maintained
+F: drivers/usb/typec/ucsi/cros_ec_ucsi.c
+
CHRONTEL CH7322 CEC DRIVER
M: Joe Tessler <jrt@google.com>
L: linux-media@vger.kernel.org
diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
index 680e1b87b152..75559601fe8f 100644
--- a/drivers/usb/typec/ucsi/Kconfig
+++ b/drivers/usb/typec/ucsi/Kconfig
@@ -69,6 +69,19 @@ config UCSI_PMIC_GLINK
To compile the driver as a module, choose M here: the module will be
called ucsi_glink.

+config CROS_EC_UCSI
+ tristate "UCSI Driver for ChromeOS EC"
+ depends on MFD_CROS_EC_DEV
+ depends on CROS_USBPD_NOTIFY
+ depends on !EXTCON_TCSS_CROS_EC
+ default MFD_CROS_EC_DEV
+ help
+ This driver enables UCSI support for a ChromeOS EC. The EC is
+ expected to implement a PPM.
+
+ To compile the driver as a module, choose M here: the module
+ will be called cros_ec_ucsi.
+
config UCSI_LENOVO_YOGA_C630
tristate "UCSI Interface Driver for Lenovo Yoga C630"
depends on EC_LENOVO_YOGA_C630
diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
index aed41d23887b..be98a879104d 100644
--- a/drivers/usb/typec/ucsi/Makefile
+++ b/drivers/usb/typec/ucsi/Makefile
@@ -21,4 +21,5 @@ 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
+obj-$(CONFIG_CROS_EC_UCSI) += cros_ec_ucsi.o
obj-$(CONFIG_UCSI_LENOVO_YOGA_C630) += ucsi_yoga_c630.o
diff --git a/drivers/usb/typec/ucsi/cros_ec_ucsi.c b/drivers/usb/typec/ucsi/cros_ec_ucsi.c
new file mode 100644
index 000000000000..6b9dc05a4960
--- /dev/null
+++ b/drivers/usb/typec/ucsi/cros_ec_ucsi.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * UCSI driver for ChromeOS EC
+ *
+ * Copyright 2024 Google LLC.
+ */
+
+#include <linux/container_of.h>
+#include <linux/dev_printk.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_usbpd_notify.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+
+#include "ucsi.h"
+
+/*
+ * Maximum size in bytes of a UCSI message between AP and EC
+ */
+#define MAX_EC_DATA_SIZE 256
+
+/*
+ * Maximum time in miliseconds the cros_ec_ucsi driver
+ * will wait for a response to a command or and ack.
+ */
+#define WRITE_TMO_MS 5000
+
+struct cros_ucsi_data {
+ struct device *dev;
+ struct ucsi *ucsi;
+
+ struct cros_ec_device *ec;
+ struct notifier_block nb;
+ struct work_struct work;
+
+ struct completion complete;
+ unsigned long flags;
+};
+
+static int cros_ucsi_read(struct ucsi *ucsi, unsigned int offset, void *val,
+ size_t val_len)
+{
+ struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
+ struct ec_params_ucsi_ppm_get req = {
+ .offset = offset,
+ .size = val_len,
+ };
+ int ret;
+
+ if (val_len > MAX_EC_DATA_SIZE) {
+ dev_err(udata->dev, "Can't read %zu bytes. Too big.", val_len);
+ return -EINVAL;
+ }
+
+ ret = cros_ec_cmd(udata->ec, 0, EC_CMD_UCSI_PPM_GET,
+ &req, sizeof(req), val, val_len);
+ if (ret < 0) {
+ dev_warn(udata->dev, "Failed to send EC message UCSI_PPM_GET: error=%d", ret);
+ return ret;
+ }
+ return 0;
+}
+
+static int cros_ucsi_read_version(struct ucsi *ucsi, u16 *version)
+{
+ return cros_ucsi_read(ucsi, UCSI_VERSION, version, sizeof(*version));
+}
+
+static int cros_ucsi_read_cci(struct ucsi *ucsi, u32 *cci)
+{
+ return cros_ucsi_read(ucsi, UCSI_CCI, cci, sizeof(*cci));
+}
+
+static int cros_ucsi_read_message_in(struct ucsi *ucsi, void *val,
+ size_t val_len)
+{
+ return cros_ucsi_read(ucsi, UCSI_MESSAGE_IN, val, val_len);
+}
+
+static int cros_ucsi_async_control(struct ucsi *ucsi, u64 cmd)
+{
+ struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
+ struct ec_params_ucsi_ppm_set *req;
+ size_t req_len;
+ int ret;
+
+ req_len = sizeof(struct ec_params_ucsi_ppm_set) + sizeof(cmd);
+ req = kzalloc(req_len, GFP_KERNEL);
+ if (!req)
+ return -ENOMEM;
+
+ req->offset = UCSI_CONTROL;
+ memcpy(req->data, &cmd, sizeof(cmd));
+ ret = cros_ec_cmd(udata->ec, 0, EC_CMD_UCSI_PPM_SET,
+ req, req_len, NULL, 0);
+ if (ret < 0) {
+ dev_warn(udata->dev, "Failed to send EC message UCSI_PPM_SET: error=%d", ret);
+ return ret;
+ }
+ return 0;
+}
+
+static int cros_ucsi_sync_control(struct ucsi *ucsi, u64 cmd)
+{
+ struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
+ bool ack = UCSI_COMMAND(cmd) == UCSI_ACK_CC_CI;
+ int ret;
+
+ if (ack)
+ set_bit(ACK_PENDING, &udata->flags);
+ else
+ set_bit(COMMAND_PENDING, &udata->flags);
+
+ ret = cros_ucsi_async_control(ucsi, cmd);
+ if (ret)
+ goto out;
+
+ if (!wait_for_completion_timeout(&udata->complete, WRITE_TMO_MS))
+ ret = -ETIMEDOUT;
+
+out:
+ if (ack)
+ clear_bit(ACK_PENDING, &udata->flags);
+ else
+ clear_bit(COMMAND_PENDING, &udata->flags);
+ return ret;
+}
+
+struct ucsi_operations cros_ucsi_ops = {
+ .read_version = cros_ucsi_read_version,
+ .read_cci = cros_ucsi_read_cci,
+ .read_message_in = cros_ucsi_read_message_in,
+ .async_control = cros_ucsi_async_control,
+ .sync_control = cros_ucsi_sync_control,
+};
+
+static void cros_ucsi_work(struct work_struct *work)
+{
+ struct cros_ucsi_data *udata = container_of(work, struct cros_ucsi_data, work);
+ u32 cci;
+
+ if (cros_ucsi_read(udata->ucsi, UCSI_CCI, &cci, sizeof(cci)))
+ return;
+
+ if (UCSI_CCI_CONNECTOR(cci))
+ ucsi_connector_change(udata->ucsi, UCSI_CCI_CONNECTOR(cci));
+
+ if (cci & UCSI_CCI_ACK_COMPLETE &&
+ test_and_clear_bit(ACK_PENDING, &udata->flags))
+ complete(&udata->complete);
+ if (cci & UCSI_CCI_COMMAND_COMPLETE &&
+ test_and_clear_bit(COMMAND_PENDING, &udata->flags))
+ complete(&udata->complete);
+}
+
+static int cros_ucsi_event(struct notifier_block *nb,
+ unsigned long host_event, void *_notify)
+{
+ struct cros_ucsi_data *udata = container_of(nb, struct cros_ucsi_data, nb);
+
+ if (!(host_event & PD_EVENT_PPM))
+ return NOTIFY_OK;
+
+ dev_dbg(udata->dev, "UCSI notification received");
+ flush_work(&udata->work);
+ schedule_work(&udata->work);
+
+ return NOTIFY_OK;
+}
+
+static void cros_ucsi_destroy(struct cros_ucsi_data *udata)
+{
+ cros_usbpd_unregister_notify(&udata->nb);
+ cancel_work_sync(&udata->work);
+ ucsi_destroy(udata->ucsi);
+}
+
+static int cros_ucsi_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct cros_ec_dev *ec_data = dev_get_drvdata(dev->parent);
+ struct cros_ucsi_data *udata;
+ int ret;
+
+ udata = devm_kzalloc(dev, sizeof(*udata), GFP_KERNEL);
+ if (!udata)
+ return -ENOMEM;
+
+ udata->dev = dev;
+
+ udata->ec = ec_data->ec_dev;
+ if (!udata->ec) {
+ dev_err(dev, "couldn't find parent EC device");
+ return -ENODEV;
+ }
+
+ platform_set_drvdata(pdev, udata);
+
+ INIT_WORK(&udata->work, cros_ucsi_work);
+ init_completion(&udata->complete);
+
+ udata->ucsi = ucsi_create(dev, &cros_ucsi_ops);
+ if (IS_ERR(udata->ucsi)) {
+ dev_err(dev, "failed to allocate UCSI instance");
+ return PTR_ERR(udata->ucsi);
+ }
+
+ ucsi_set_drvdata(udata->ucsi, udata);
+
+ udata->nb.notifier_call = cros_ucsi_event;
+ ret = cros_usbpd_register_notify(&udata->nb);
+ if (ret) {
+ dev_err(dev, "failed to register notifier: error=%d", ret);
+ ucsi_destroy(udata->ucsi);
+ return ret;
+ }
+
+ ret = ucsi_register(udata->ucsi);
+ if (ret) {
+ dev_err(dev, "failed to register UCSI: error=%d", ret);
+ cros_ucsi_destroy(udata);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void cros_ucsi_remove(struct platform_device *dev)
+{
+ struct cros_ucsi_data *udata = platform_get_drvdata(dev);
+
+ ucsi_unregister(udata->ucsi);
+ cros_ucsi_destroy(udata);
+}
+
+static int __maybe_unused cros_ucsi_suspend(struct device *dev)
+{
+ struct cros_ucsi_data *udata = dev_get_drvdata(dev);
+
+ cancel_work_sync(&udata->work);
+
+ return 0;
+}
+
+static int __maybe_unused cros_ucsi_resume(struct device *dev)
+{
+ struct cros_ucsi_data *udata = dev_get_drvdata(dev);
+
+ return ucsi_resume(udata->ucsi);
+}
+
+static SIMPLE_DEV_PM_OPS(cros_ucsi_pm_ops, cros_ucsi_suspend,
+ cros_ucsi_resume);
+
+static const struct platform_device_id cros_ucsi_id[] = {
+ { KBUILD_MODNAME, 0 },
+ {}
+};
+MODULE_DEVICE_TABLE(platform, cros_ucsi_id);
+
+static struct platform_driver cros_ucsi_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .pm = &cros_ucsi_pm_ops,
+ },
+ .id_table = cros_ucsi_id,
+ .probe = cros_ucsi_probe,
+ .remove = cros_ucsi_remove,
+};
+
+module_platform_driver(cros_ucsi_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("UCSI driver for ChromeOS EC");
--
2.46.0.469.g59c65b2a67-goog