Re: [PATCH 3/5] usb: typec: ucsi: add Huawei Matebook E Go (sc8280xp) ucsi driver

[Pengyu Luo <mitltlatltl@gmail.com>]

On Sat, Dec 28, 2024 at 9:06 PM Bryan O'Donoghue <bryan.odonoghue@linaro.org> wrote:
> On 27/12/2024 17:13, Pengyu Luo wrote:
> > The Huawei Matebook E Go (sc8280xp) tablet provides implements UCSI
> > interface in the onboard EC. Add the glue driver to interface the
> > platform's UCSI implementation.
> >
> > Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
> > ---
> >   drivers/usb/typec/ucsi/Kconfig              |   9 +
> >   drivers/usb/typec/ucsi/Makefile             |   1 +
> >   drivers/usb/typec/ucsi/ucsi_huawei_gaokun.c | 481 ++++++++++++++++++++
> >   3 files changed, 491 insertions(+)
> >   create mode 100644 drivers/usb/typec/ucsi/ucsi_huawei_gaokun.c
> >
> > diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
> > index 680e1b87b..0d0f07488 100644
> > --- a/drivers/usb/typec/ucsi/Kconfig
> > +++ b/drivers/usb/typec/ucsi/Kconfig
> > @@ -78,4 +78,13 @@ config UCSI_LENOVO_YOGA_C630
> >         To compile the driver as a module, choose M here: the module will be
> >         called ucsi_yoga_c630.
> >
> > +config UCSI_HUAWEI_GAOKUN
> > +     tristate "UCSI Interface Driver for Huawei Matebook E Go (sc8280xp)"
> > +     depends on EC_HUAWEI_GAOKUN
> > +     help
> > +       This driver enables UCSI support on the Huawei Matebook E Go tablet.
> > +
> > +       To compile the driver as a module, choose M here: the module will be
> > +       called ucsi_huawei_gaokun.
> > +
> >   endif
> > diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
> > index aed41d238..0b400122b 100644
> > --- a/drivers/usb/typec/ucsi/Makefile
> > +++ b/drivers/usb/typec/ucsi/Makefile
> > @@ -22,3 +22,4 @@ obj-$(CONFIG_UCSI_CCG)                      += ucsi_ccg.o
> >   obj-$(CONFIG_UCSI_STM32G0)          += ucsi_stm32g0.o
> >   obj-$(CONFIG_UCSI_PMIC_GLINK)               += ucsi_glink.o
> >   obj-$(CONFIG_UCSI_LENOVO_YOGA_C630) += ucsi_yoga_c630.o
> > +obj-$(CONFIG_UCSI_HUAWEI_GAOKUN)     += ucsi_huawei_gaokun.o
> > diff --git a/drivers/usb/typec/ucsi/ucsi_huawei_gaokun.c b/drivers/usb/typec/ucsi/ucsi_huawei_gaokun.c
> > new file mode 100644
> > index 000000000..84ed0407d
> > --- /dev/null
> > +++ b/drivers/usb/typec/ucsi/ucsi_huawei_gaokun.c
> > @@ -0,0 +1,481 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * ucsi-huawei-gaokun - A UCSI driver for HUAWEI Matebook E Go (sc8280xp)
> > + *
> > + * reference: drivers/usb/typec/ucsi/ucsi_yoga_c630.c
> > + *            drivers/usb/typec/ucsi/ucsi_glink.c
> > + *            drivers/soc/qcom/pmic_glink_altmode.c
> > + *
> > + * Copyright (C) 2024 Pengyu Luo <mitltlatltl@gmail.com>
> > + */
> > +
> > +#include <linux/auxiliary_bus.h>
> > +#include <linux/bitops.h>
> > +#include <linux/completion.h>
> > +#include <linux/container_of.h>
> > +#include <linux/delay.h>
> > +#include <linux/module.h>
> > +#include <linux/notifier.h>
> > +#include <linux/of.h>
> > +#include <linux/string.h>
> > +#include <linux/workqueue_types.h>
> > +
> > +#include <linux/usb/pd_vdo.h>
> > +#include <drm/bridge/aux-bridge.h
>
> Is there a reason you don't have strict include alphanumeric ordering here ?
>

These two is dp/alt mode related, so listing them out. Above of them are
general things.

> >
> > +
> > +#include "ucsi.h"
> > +#include <linux/platform_data/huawei-gaokun-ec.h>
> > +
> > +
> > +#define EC_EVENT_UCSI        0x21
> > +#define EC_EVENT_USB 0x22
> > +
> > +#define GAOKUN_CCX_MASK              GENMASK(1, 0)
> > +#define GAOKUN_MUX_MASK              GENMASK(3, 2)
> > +
> > +#define GAOKUN_DPAM_MASK     GENMASK(3, 0)
> > +#define GAOKUN_HPD_STATE_MASK        BIT(4)
> > +#define GAOKUN_HPD_IRQ_MASK  BIT(5)
> > +
> > +#define CCX_TO_ORI(ccx) (++ccx % 3)
>
> Why do you increment the value of the enum ?
> Seems strange.
>

EC's logic, it is just a trick. Qualcomm maps
0 1 2 to normal, reverse, none(no device insert)
typec lib maps 1 2 0 to that.

> > +
> > +#define GET_IDX(updt) (ffs(updt) - 1)
> > +
> > +/* Configuration Channel Extension */
> > +enum gaokun_ucsi_ccx {
> > +     USBC_CCX_NORMAL,
> > +     USBC_CCX_REVERSE,
> > +     USBC_CCX_NONE,
> > +};
> > +
> > +enum gaokun_ucsi_mux {
> > +     USBC_MUX_NONE,
> > +     USBC_MUX_USB_2L,
> > +     USBC_MUX_DP_4L,
> > +     USBC_MUX_USB_DP,
> > +};
> > +
> > +struct gaokun_ucsi_reg {
> > +     u8 port_num;
> > +     u8 port_updt;
> > +     u8 port_data[4];
> > +     u8 checksum;
> > +     u8 reserved;
> > +} __packed;
> > +
> > +struct gaokun_ucsi_port {
> > +     struct completion usb_ack;
> > +     spinlock_t lock;
> > +
> > +     struct gaokun_ucsi *ucsi;
> > +     struct auxiliary_device *bridge;
> > +
> > +     int idx;
> > +     enum gaokun_ucsi_ccx ccx;
> > +     enum gaokun_ucsi_mux mux;
> > +     u8 mode;
> > +     u16 svid;
> > +     u8 hpd_state;
> > +     u8 hpd_irq;
> > +};
> > +
> > +struct gaokun_ucsi {
> > +     struct gaokun_ec *ec;
> > +     struct ucsi *ucsi;
> > +     struct gaokun_ucsi_port *ports;
> > +     struct device *dev;
> > +     struct work_struct work;
> > +     struct notifier_block nb;
> > +     u16 version;
> > +     u8 port_num;
> > +};
> > +
> > +/* -------------------------------------------------------------------------- */
> > +/* For UCSI */
> > +
> > +static int gaokun_ucsi_read_version(struct ucsi *ucsi, u16 *version)
> > +{
> > +     struct gaokun_ucsi *uec = ucsi_get_drvdata(ucsi);
> > +
> > +     *version = uec->version;
> > +
> > +     return 0;
> > +}
> > +
> > +static int gaokun_ucsi_read_cci(struct ucsi *ucsi, u32 *cci)
> > +{
> > +     struct gaokun_ucsi *uec = ucsi_get_drvdata(ucsi);
> > +     u8 buf[GAOKUN_UCSI_READ_SIZE];
> > +     int ret;
> > +
> > +     ret = gaokun_ec_ucsi_read(uec->ec, buf);
> > +     if (ret)
> > +             return ret;
> > +
> > +     memcpy(cci, buf, sizeof(*cci));
> > +
> > +     return 0;
> > +}
> > +
> > +static int gaokun_ucsi_read_message_in(struct ucsi *ucsi,
> > +                                    void *val, size_t val_len)
> > +{
> > +     struct gaokun_ucsi *uec = ucsi_get_drvdata(ucsi);
> > +     u8 buf[GAOKUN_UCSI_READ_SIZE];
> > +     int ret;
> > +
> > +     ret = gaokun_ec_ucsi_read(uec->ec, buf);
> > +     if (ret)
> > +             return ret;
> > +
> > +     memcpy(val, buf + GAOKUN_UCSI_CCI_SIZE,
> > +            min(val_len, GAOKUN_UCSI_DATA_SIZE));
> > +
> > +     return 0;
> > +}
> > +
> > +static int gaokun_ucsi_async_control(struct ucsi *ucsi, u64 command)
> > +{
> > +     struct gaokun_ucsi *uec = ucsi_get_drvdata(ucsi);
> > +     u8 buf[GAOKUN_UCSI_WRITE_SIZE] = {};
> > +
> > +     memcpy(buf, &command, sizeof(command));
> > +
> > +     return gaokun_ec_ucsi_write(uec->ec, buf);
> > +}
> > +
> > +static void gaokun_ucsi_update_connector(struct ucsi_connector *con)
> > +{
> > +     struct gaokun_ucsi *uec = ucsi_get_drvdata(con->ucsi);
> > +
> > +     if (con->num > uec->port_num)
> > +             return;
> > +
> > +     con->typec_cap.orientation_aware = true;
> > +}
> > +
> > +static void gaokun_set_orientation(struct ucsi_connector *con,
> > +                                struct gaokun_ucsi_port *port)
> > +{
> > +     enum gaokun_ucsi_ccx ccx;
> > +     unsigned long flags;
> > +
> > +     spin_lock_irqsave(&port->lock, flags);
> > +     ccx = port->ccx;
> > +     spin_unlock_irqrestore(&port->lock, flags);
> > +
> > +     typec_set_orientation(con->port, CCX_TO_ORI(ccx));
> > +}
> > +
> > +static void gaokun_ucsi_connector_status(struct ucsi_connector *con)
> > +{
> > +     struct gaokun_ucsi *uec = ucsi_get_drvdata(con->ucsi);
> > +     int idx;
> > +
> > +     idx = con->num - 1;
> > +     if (con->num > uec->port_num) {
> > +             dev_warn(uec->ucsi->dev, "set orientation out of range: con%d\n", idx);
> > +             return;
> > +     }
> > +
> > +     gaokun_set_orientation(con, &uec->ports[idx]);
> > +}
> > +
> > +const struct ucsi_operations gaokun_ucsi_ops = {
> > +     .read_version = gaokun_ucsi_read_version,
> > +     .read_cci = gaokun_ucsi_read_cci,
> > +     .read_message_in = gaokun_ucsi_read_message_in,
> > +     .sync_control = ucsi_sync_control_common,
> > +     .async_control = gaokun_ucsi_async_control,
> > +     .update_connector = gaokun_ucsi_update_connector,
> > +     .connector_status = gaokun_ucsi_connector_status,
> > +};
> > +
> > +/* -------------------------------------------------------------------------- */
> > +/* For Altmode */
> > +
> > +static void gaokun_ucsi_port_update(struct gaokun_ucsi_port *port,
> > +                                 const u8 *port_data)
> > +{
> > +     unsigned long flags;
> > +     u8 dcc, ddi;
> > +     int offset = port->idx * 2; /* every port has 2 Bytes data */
> > +
> > +     dcc = port_data[offset];
> > +     ddi = port_data[offset + 1];
> > +
> > +     spin_lock_irqsave(&port->lock, flags);
> > +
> > +     port->ccx = FIELD_GET(GAOKUN_CCX_MASK, dcc);
> > +     port->mux = FIELD_GET(GAOKUN_MUX_MASK, dcc);
> > +     port->mode = FIELD_GET(GAOKUN_DPAM_MASK, ddi);
> > +     port->hpd_state = FIELD_GET(GAOKUN_HPD_STATE_MASK, ddi);
> > +     port->hpd_irq = FIELD_GET(GAOKUN_HPD_IRQ_MASK, ddi);
> > +
> > +     switch (port->mux) {
> > +     case USBC_MUX_NONE:
> > +             port->svid = 0;
> > +             break;
> > +     case USBC_MUX_USB_2L:
> > +             port->svid = USB_SID_PD;
> > +             break;
> > +     case USBC_MUX_DP_4L:
> > +     case USBC_MUX_USB_DP:
> > +             port->svid = USB_SID_DISPLAYPORT;
> > +             if (port->ccx == USBC_CCX_REVERSE)
> > +                     port->mode -= 6;
>
> why minus six ?
> needs a comment.
>

EC's logic. I don't know why, it is a quirk from Qualcomm or Huawei.
I will mention this.

> > +             break;
> > +     default:
> > +             break;
> > +     }
> > +
> > +     spin_unlock_irqrestore(&port->lock, flags);
> > +}
> > +
> > +static int gaokun_ucsi_refresh(struct gaokun_ucsi *uec)
> > +{
> > +     struct gaokun_ucsi_reg ureg;
> > +     int ret, idx;
> > +
> > +     ret = gaokun_ec_ucsi_get_reg(uec->ec, (u8 *)&ureg);
> > +     if (ret)
> > +             return -EIO;
> > +
> > +     uec->port_num = ureg.port_num;
> > +     idx = GET_IDX(ureg.port_updt);
> > +
> > +     if (idx >= 0 && idx < ureg.port_num)
> > +             gaokun_ucsi_port_update(&uec->ports[idx], ureg.port_data);
>
> Since you are checking the validity of the index, you should -EINVAL if
> the index is out of range.
>

EC / pmic glink encode every port in a bit
0/1/2/4/... => ???/left/right/some port

I remap it to -1/0/1/2, to access specific port exceptions(-1) are not
harmful, later in gaokun_ucsi_altmode_notify_ind

	if (idx < 0)
		gaokun_ec_ucsi_pan_ack(uec->ec, idx);
	else
		gaokun_ucsi_handle_altmode(&uec->ports[idx]);

gaokun_ec_ucsi_pan_ack can handle exceptions.

> > +
> > +     return idx;
> > +}
> > +
> > +static void gaokun_ucsi_handle_altmode(struct gaokun_ucsi_port *port)
> > +{
> > +     struct gaokun_ucsi *uec = port->ucsi;
> > +     int idx = port->idx;
> > +
> > +     if (idx >= uec->ucsi->cap.num_connectors || !uec->ucsi->connector) {
> > +             dev_warn(uec->ucsi->dev, "altmode port out of range: %d\n", idx);
> > +             return;
> > +     }
> > +
> > +     /* UCSI callback .connector_status() have set orientation */
> > +     if (port->bridge)
> > +             drm_aux_hpd_bridge_notify(&port->bridge->dev,
> > +                                       port->hpd_state ?
> > +                                       connector_status_connected :
> > +                                       connector_status_disconnected);
> > +
> > +     gaokun_ec_ucsi_pan_ack(uec->ec, port->idx);
> > +}
> > +
> > +static void gaokun_ucsi_altmode_notify_ind(struct gaokun_ucsi *uec)
> > +{
> > +     int idx;
> > +
> > +     idx = gaokun_ucsi_refresh(uec);
> > +     if (idx < 0)
> > +             gaokun_ec_ucsi_pan_ack(uec->ec, idx);
> > +     else
> > +             gaokun_ucsi_handle_altmode(&uec->ports[idx]);
> > +}
> > +
> > +/*
> > + * USB event is necessary for enabling altmode, the event should follow
> > + * UCSI event, if not after timeout(this notify may be disabled somehow),
> > + * then force to enable altmode.
> > + */
> > +static void gaokun_ucsi_handle_no_usb_event(struct gaokun_ucsi *uec, int idx)
> > +{
> > +     struct gaokun_ucsi_port *port;
> > +
> > +     port = &uec->ports[idx];
> > +     if (!wait_for_completion_timeout(&port->usb_ack, 2 * HZ)) {
> > +             dev_warn(uec->dev, "No USB EVENT, triggered by UCSI EVENT");
> > +             gaokun_ucsi_altmode_notify_ind(uec);
> > +     }
> > +}
> > +
> > +static int gaokun_ucsi_notify(struct notifier_block *nb,
> > +                           unsigned long action, void *data)
> > +{
> > +     u32 cci;
> > +     struct gaokun_ucsi *uec = container_of(nb, struct gaokun_ucsi, nb);
> > +
> > +     switch (action) {
> > +     case EC_EVENT_USB:
> > +             gaokun_ucsi_altmode_notify_ind(uec);
> > +             return NOTIFY_OK;
> > +
> > +     case EC_EVENT_UCSI:
> > +             uec->ucsi->ops->read_cci(uec->ucsi, &cci);
> > +             ucsi_notify_common(uec->ucsi, cci);
> > +             if (UCSI_CCI_CONNECTOR(cci))
> > +                     gaokun_ucsi_handle_no_usb_event(uec, UCSI_CCI_CONNECTOR(cci) - 1);
> > +
> > +             return NOTIFY_OK;
> > +
> > +     default:
> > +             return NOTIFY_DONE;
> > +     }
> > +}
> > +
> > +static int gaokun_ucsi_get_port_num(struct gaokun_ucsi *uec)
> > +{
> > +     struct gaokun_ucsi_reg ureg;
> > +     int ret;
> > +
> > +     ret = gaokun_ec_ucsi_get_reg(uec->ec, (u8 *)&ureg);
> > +
> > +     return ret ? 0 : ureg.port_num;
> > +}
> > +
> > +static int gaokun_ucsi_ports_init(struct gaokun_ucsi *uec)
> > +{
> > +     u32 port;
> > +     int i, ret, port_num;
> > +     struct device *dev = uec->dev;
> > +     struct gaokun_ucsi_port *ucsi_port;
> > +     struct fwnode_handle *fwnode;
> > +
> > +     port_num = gaokun_ucsi_get_port_num(uec);
> > +     uec->port_num = port_num;
> > +
> > +     uec->ports = devm_kzalloc(dev, port_num * sizeof(*(uec->ports)),
> > +                               GFP_KERNEL);
> > +     if (!uec->ports)
> > +             return -ENOMEM;
> > +
> > +     for (i = 0; i < port_num; ++i) {
> > +             ucsi_port = &uec->ports[i];
> > +             ucsi_port->ccx = USBC_CCX_NONE;
> > +             ucsi_port->idx = i;
> > +             ucsi_port->ucsi = uec;
> > +             init_completion(&ucsi_port->usb_ack);
> > +             spin_lock_init(&ucsi_port->lock);
> > +     }
> > +
> > +     device_for_each_child_node(dev, fwnode) {
> > +             ret = fwnode_property_read_u32(fwnode, "reg", &port);
> > +             if (ret < 0) {
> > +                     dev_err(dev, "missing reg property of %pOFn\n", fwnode);
> > +                     fwnode_handle_put(fwnode);
> > +                     return ret;
> > +             }
> > +
> > +             if (port >= port_num) {
> > +                     dev_warn(dev, "invalid connector number %d, ignoring\n", port);
> > +                     continue;
> > +             }
> > +
> > +             ucsi_port = &uec->ports[port];
> > +             ucsi_port->bridge = devm_drm_dp_hpd_bridge_alloc(dev, to_of_node(fwnode));
> > +             if (IS_ERR(ucsi_port->bridge)) {
> > +                     fwnode_handle_put(fwnode);
> > +                     return PTR_ERR(ucsi_port->bridge);
> > +             }
> > +     }
> > +
> > +     for (i = 0; i < port_num; i++) {
> > +             if (!uec->ports[i].bridge)
> > +                     continue;
> > +
> > +             ret = devm_drm_dp_hpd_bridge_add(dev, uec->ports[i].bridge);
> > +             if (ret)
> > +                     return ret;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static void gaokun_ucsi_register_worker(struct work_struct *work)
> > +{
> > +     struct gaokun_ucsi *uec;
> > +     struct ucsi *ucsi;
> > +     int ret;
> > +
> > +     uec = container_of(work, struct gaokun_ucsi, work);
> > +     ucsi = uec->ucsi;
> > +
> > +     ucsi->quirks = UCSI_NO_PARTNER_PDOS | UCSI_DELAY_DEVICE_PDOS;
> > +
> > +     ssleep(3); /* EC can't handle UCSI properly in the early stage */
>
> Could you not schedule work for + 3 seconds instead of sleeping here -
> representing the required stall time in some sort of state machine ?
>

I see, I will check work schedule interface.

> 3 seconds is an incredibly long time for a computer to sleep.
>

This module will be loaded at about 5th second after power up, if not
sleep, we will receive something disharmonious, sleeping for 3 seconds is
a hack.

> > +
> > +     ret = gaokun_ec_register_notify(uec->ec, &uec->nb);
> > +     if (ret) {
> > +             dev_err_probe(ucsi->dev, ret, "notifier register failed\n");
> > +             return;
> > +     }
> > +
> > +     ret = ucsi_register(ucsi);
> > +     if (ret)
> > +             dev_err_probe(ucsi->dev, ret, "ucsi register failed\n");
> > +}
> > +
> > +static int gaokun_ucsi_register(struct gaokun_ucsi *uec)
> > +{
> > +     schedule_work(&uec->work);
> > +
> > +     return 0;
> > +}
> > +
> > +static int gaokun_ucsi_probe(struct auxiliary_device *adev,
> > +                          const struct auxiliary_device_id *id)
> > +{
> > +     struct gaokun_ec *ec = adev->dev.platform_data;
> > +     struct device *dev = &adev->dev;
> > +     struct gaokun_ucsi *uec;
> > +     int ret;
> > +
> > +     uec = devm_kzalloc(dev, sizeof(*uec), GFP_KERNEL);
> > +     if (!uec)
> > +             return -ENOMEM;
> > +
> > +     uec->ec = ec;
> > +     uec->dev = dev;
> > +     uec->version = 0x0100;
> > +     uec->nb.notifier_call = gaokun_ucsi_notify;
> > +
> > +     INIT_WORK(&uec->work, gaokun_ucsi_register_worker);
> > +
> > +     ret = gaokun_ucsi_ports_init(uec);
> > +     if (ret)
> > +             return ret;
> > +
> > +     uec->ucsi = ucsi_create(dev, &gaokun_ucsi_ops);
> > +     if (IS_ERR(uec->ucsi))
> > +             return PTR_ERR(uec->ucsi);
> > +
> > +     ucsi_set_drvdata(uec->ucsi, uec);
> > +     auxiliary_set_drvdata(adev, uec);
> > +
> > +     return gaokun_ucsi_register(uec);
> > +}
> > +
> > +static void gaokun_ucsi_remove(struct auxiliary_device *adev)
> > +{
> > +     struct gaokun_ucsi *uec = auxiliary_get_drvdata(adev);
> > +
> > +     gaokun_ec_unregister_notify(uec->ec, &uec->nb);
> > +     ucsi_unregister(uec->ucsi);
> > +     ucsi_destroy(uec->ucsi);
> > +}
> > +
> > +static const struct auxiliary_device_id gaokun_ucsi_id_table[] = {
> > +     { .name = GAOKUN_MOD_NAME "." GAOKUN_DEV_UCSI, },
> > +     {}
> > +};
> > +MODULE_DEVICE_TABLE(auxiliary, gaokun_ucsi_id_table);
> > +
> > +static struct auxiliary_driver gaokun_ucsi_driver = {
> > +     .name = GAOKUN_DEV_UCSI,
> > +     .id_table = gaokun_ucsi_id_table,
> > +     .probe = gaokun_ucsi_probe,
> > +     .remove = gaokun_ucsi_remove,
> > +};
> > +
> > +module_auxiliary_driver(gaokun_ucsi_driver);
> > +
> > +MODULE_DESCRIPTION("HUAWEI Matebook E Go UCSI driver");
> > +MODULE_LICENSE("GPL");
>


Best Wishes,
Pengyu