On Mon, Dec 9, 2024 at 5:48 PM Abhishek Pandit-Subedi
<abhishekpandit@xxxxxxxxxxxx> wrote:
>
> 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.
>
You're right. I need to send the next patchset version then.
Stay tuned ;).
Thanks,
Lukasz
> > + 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
> >
