On Wed, Dec 4, 2024 at 11:49 AM Łukasz Bartosik <ukaszb@xxxxxxxxxxxx> wrote:
>
> From: Pavan Holla <pholla@xxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxx>
> Co-developed-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
> Co-developed-by: Łukasz Bartosik <ukaszb@xxxxxxxxxxxx>
> Signed-off-by: Łukasz Bartosik <ukaszb@xxxxxxxxxxxx>
> ---
> MAINTAINERS | 7 +
> drivers/usb/typec/ucsi/Kconfig | 13 +
> drivers/usb/typec/ucsi/Makefile | 1 +
> drivers/usb/typec/ucsi/cros_ec_ucsi.c | 337 ++++++++++++++++++++++++++
> 4 files changed, 358 insertions(+)
> create mode 100644 drivers/usb/typec/ucsi/cros_ec_ucsi.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 1e930c7a58b1..36eebe1ad078 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -5452,6 +5452,13 @@ L: chrome-platform@xxxxxxxxxxxxxxx
> S: Maintained
> F: drivers/watchdog/cros_ec_wdt.c
>
> +CHROMEOS UCSI DRIVER
> +M: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
> +M: Łukasz Bartosik <ukaszb@xxxxxxxxxxxx>
> +L: chrome-platform@xxxxxxxxxxxxxxx
> +S: Maintained
> +F: drivers/usb/typec/ucsi/cros_ec_ucsi.c
> +
> CHRONTEL CH7322 CEC DRIVER
> M: Joe Tessler <jrt@xxxxxxxxxx>
> L: linux-media@xxxxxxxxxxxxxxx
> 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..cd2231d6a0ea
> --- /dev/null
> +++ b/drivers/usb/typec/ucsi/cros_ec_ucsi.c
> @@ -0,0 +1,337 @@
> +// 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/jiffies.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 milliseconds the cros_ec_ucsi driver
> + * will wait for a response to a command or and ack.
> + */
> +#define WRITE_TMO_MS 5000
> +
> +/* Number of times to attempt recovery from a write timeout before giving up. */
> +#define WRITE_TMO_CTR_MAX 5
> +
> +struct cros_ucsi_data {
> + struct device *dev;
> + struct ucsi *ucsi;
> +
> + struct cros_ec_device *ec;
> + struct notifier_block nb;
> + struct work_struct work;
> + struct delayed_work write_tmo;
> + int tmo_counter;
> +
> + 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);
> + u8 ec_buf[sizeof(struct ec_params_ucsi_ppm_set) + sizeof(cmd)];
> + struct ec_params_ucsi_ppm_set *req = (struct ec_params_ucsi_ppm_set *) ec_buf;
> + int ret;
> +
> + req->offset = UCSI_CONTROL;
> + memcpy(req->data, &cmd, sizeof(cmd));
> + ret = cros_ec_cmd(udata->ec, 0, EC_CMD_UCSI_PPM_SET,
> + req, sizeof(ec_buf), 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);
> + int ret;
> +
> + ret = ucsi_sync_control_common(ucsi, cmd);
> + switch (ret) {
> + case -EBUSY:
> + /* EC may return -EBUSY if CCI.busy is set.
> + * Convert this to a timeout.
> + */
> + case -ETIMEDOUT:
> + /* Schedule recovery attempt when we timeout
> + * or tried to send a command while still busy.
> + */
> + cancel_delayed_work_sync(&udata->write_tmo);
> + schedule_delayed_work(&udata->write_tmo,
> + msecs_to_jiffies(WRITE_TMO_MS));
> + break;
> + case 0:
> + /* Successful write. Cancel any pending recovery work. */
> + cancel_delayed_work_sync(&udata->write_tmo);
> + break;
> + }
> +
> + 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_cci(udata->ucsi, &cci))
> + return;
> +
> + ucsi_notify_common(udata->ucsi, cci);
> +}
> +
> +static void cros_ucsi_write_timeout(struct work_struct *work)
> +{
> + struct cros_ucsi_data *udata =
> + container_of(work, struct cros_ucsi_data, write_tmo.work);
> + u32 cci;
> + u64 cmd;
> +
> + if (cros_ucsi_read(udata->ucsi, UCSI_CCI, &cci, sizeof(cci))) {
> + dev_err(udata->dev,
> + "Reading CCI failed; no write timeout recovery possible.");
> + return;
> + }
> +
> + if (cci & UCSI_CCI_BUSY) {
> + udata->tmo_counter++;
> +
> + if (udata->tmo_counter <= WRITE_TMO_CTR_MAX)
> + schedule_delayed_work(&udata->write_tmo,
> + msecs_to_jiffies(WRITE_TMO_MS));
> + else
> + dev_err(udata->dev,
> + "PPM unresponsive - too many write timeouts.");
> +
> + return;
> + }
> +
> + /* No longer busy means we can reset our timeout counter. */
> + udata->tmo_counter = 0;
> +
> + /* Need to ack previous command which may have timed out. */
> + if (cci & UCSI_CCI_COMMAND_COMPLETE) {
> + cmd = UCSI_ACK_CC_CI | UCSI_ACK_COMMAND_COMPLETE;
> + cros_ucsi_async_control(udata->ucsi, &cmd);
> +
> + /* Check again after a few seconds that the system has
> + * recovered to make sure our async write above was successful.
> + */
> + schedule_delayed_work(&udata->write_tmo,
> + msecs_to_jiffies(WRITE_TMO_MS));
> + return;
> + }
> +
> + /* We recovered from a previous timeout. Treat this as a recovery from
> + * suspend and call resume.
> + */
> + ucsi_resume(udata->ucsi);
> +}
> +
> +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_delayed_work(&udata->write_tmo);
Prefer cancel_delayed_work_sync.
> + 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_DELAYED_WORK(&udata->write_tmo, cros_ucsi_write_timeout);
> + 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_delayed_work(&udata->write_tmo);
This should probably be cancel_delayed_work_sync. Otherwise, the
writes coming from that work item may cause an interrupt after this
suspend method completes.
> + cancel_work_sync(&udata->work);
> +
> + return 0;
> +}
> +
> +static void __maybe_unused cros_ucsi_complete(struct device *dev)
> +{
> + struct cros_ucsi_data *udata = dev_get_drvdata(dev);
> +
> + ucsi_resume(udata->ucsi);
> +}
> +
> +/*
> + * UCSI protocol is also used on ChromeOS platforms which reply on
> + * cros_ec_lpc.c driver for communication with embedded controller (EC).
> + * On such platforms communication with the EC is not available until
> + * the .complete() callback of the cros_ec_lpc driver is executed.
> + * For this reason we delay ucsi_resume() until the .complete() stage
> + * otherwise UCSI SET_NOTIFICATION_ENABLE command will fail and we won't
> + * receive any UCSI notifications from the EC where PPM is implemented.
> + */
> +static const struct dev_pm_ops cros_ucsi_pm_ops = {
> +#ifdef CONFIG_PM_SLEEP
> + .suspend = cros_ucsi_suspend,
> + .complete = cros_ucsi_complete,
> +#endif
> +};
> +
> +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");
> --
> 2.47.0.338.g60cca15819-goog
>
