Re: [PATCH v2 3/4] soc: qcom: pmic_glink: Introduce altmode support
From: Neil Armstrong
Date: Fri Jan 20 2023 - 05:33:44 EST
On 20/01/2023 11:06, Neil Armstrong wrote:
On 13/01/2023 05:11, Bjorn Andersson wrote:
From: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
With the PMIC GLINK service, the host OS subscribes to USB-C altmode
messages, which are sent by the firmware to notify the host OS about
state updates and HPD interrupts.
The pmic_glink_altmode driver registers for these notifications and
propagates the notifications as typec_mux, typec_switch and DRM OOB
notifications as necessary to implement DisplayPort altmode support.
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Signed-off-by: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
---
Changes since v1:
- None
Johan reported a NULL pointer dereference in
drm_kms_helper_hotplug_event() for HPD event being reported while the
MSM DRM driver is still being initalized, a separate fix has been sent
in hope to remidy this race condition in the MSM driver.
drivers/soc/qcom/Makefile | 1 +
drivers/soc/qcom/pmic_glink_altmode.c | 477 ++++++++++++++++++++++++++
2 files changed, 478 insertions(+)
create mode 100644 drivers/soc/qcom/pmic_glink_altmode.c
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 29cccac472f3..f30552bf4da7 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_QCOM_MDT_LOADER) += mdt_loader.o
obj-$(CONFIG_QCOM_OCMEM) += ocmem.o
obj-$(CONFIG_QCOM_PDR_HELPERS) += pdr_interface.o
obj-$(CONFIG_QCOM_PMIC_GLINK) += pmic_glink.o
+obj-$(CONFIG_QCOM_PMIC_GLINK) += pmic_glink_altmode.o
obj-$(CONFIG_QCOM_QMI_HELPERS) += qmi_helpers.o
qmi_helpers-y += qmi_encdec.o qmi_interface.o
obj-$(CONFIG_QCOM_RAMP_CTRL) += ramp_controller.o
diff --git a/drivers/soc/qcom/pmic_glink_altmode.c b/drivers/soc/qcom/pmic_glink_altmode.c
new file mode 100644
index 000000000000..8d2d563cb756
--- /dev/null
+++ b/drivers/soc/qcom/pmic_glink_altmode.c
@@ -0,0 +1,477 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2019-2020, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2022, 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 <drm/drm_bridge.h>
+
+#include <linux/usb/typec_altmode.h>
+#include <linux/usb/typec_dp.h>
+#include <linux/usb/typec_mux.h>
+
+#include <linux/soc/qcom/pmic_glink.h>
+
+#define PMIC_GLINK_MAX_PORTS 2
+
+#define USBC_SC8180X_NOTIFY_IND 0x13
+#define USBC_CMD_WRITE_REQ 0x15
+#define USBC_NOTIFY_IND 0x16
+
+#define ALTMODE_PAN_EN 0x10
+#define ALTMODE_PAN_ACK 0x11
+
+struct usbc_write_req {
+ struct pmic_glink_hdr hdr;
+ __le32 cmd;
+ __le32 arg;
+ __le32 reserved;
+};
+
+#define NOTIFY_PAYLOAD_SIZE 16
+struct usbc_notify {
+ struct pmic_glink_hdr hdr;
+ char payload[NOTIFY_PAYLOAD_SIZE];
+ u32 reserved;
+};
+
+struct usbc_sc8180x_notify {
+ struct pmic_glink_hdr hdr;
+ __le32 notification;
+ __le32 reserved[2];
+};
+
+enum pmic_glink_altmode_pin_assignment {
+ DPAM_HPD_OUT,
+ DPAM_HPD_A,
+ DPAM_HPD_B,
+ DPAM_HPD_C,
+ DPAM_HPD_D,
+ DPAM_HPD_E,
+ DPAM_HPD_F,
+};
+
+struct pmic_glink_altmode;
+
+#define work_to_altmode_port(w) container_of((w), struct pmic_glink_altmode_port, work)
+
+struct pmic_glink_altmode_port {
+ struct pmic_glink_altmode *altmode;
+ unsigned int index;
+
+ struct typec_switch *typec_switch;
+ struct typec_mux *typec_mux;
+ struct typec_mux_state state;
+ struct typec_altmode dp_alt;
+
+ struct work_struct work;
+
+ struct drm_bridge bridge;
+
+ enum typec_orientation orientation;
+ u16 svid;
+ u8 dp_data;
+ u8 mode;
+ u8 hpd_state;
+ u8 hpd_irq;
+};
+
+#define work_to_altmode(w) container_of((w), struct pmic_glink_altmode, enable_work)
+
+struct pmic_glink_altmode {
+ struct device *dev;
+
+ unsigned int owner_id;
+
+ /* To synchronize WRITE_REQ acks */
+ struct mutex lock;
+
+ struct completion pan_ack;
+ struct pmic_glink_client *client;
+
+ struct work_struct enable_work;
+
+ struct pmic_glink_altmode_port ports[PMIC_GLINK_MAX_PORTS];
+};
+
+static int pmic_glink_altmode_request(struct pmic_glink_altmode *altmode, u32 cmd, u32 arg)
+{
+ struct usbc_write_req req = {};
+ unsigned long left;
+ int ret;
+
+ /*
+ * The USBC_CMD_WRITE_REQ ack doesn't identify the request, so wait for
+ * one ack at a time.
+ */
+ mutex_lock(&altmode->lock);
+
+ req.hdr.owner = cpu_to_le32(altmode->owner_id);
+ req.hdr.type = cpu_to_le32(PMIC_GLINK_REQ_RESP);
+ req.hdr.opcode = cpu_to_le32(USBC_CMD_WRITE_REQ);
+ req.cmd = cpu_to_le32(cmd);
+ req.arg = cpu_to_le32(arg);
+
+ ret = pmic_glink_send(altmode->client, &req, sizeof(req));
+ if (ret) {
+ dev_err(altmode->dev, "failed to send altmode request: %#x (%d)\n", cmd, ret);
+ goto out_unlock;
+ }
+
+ left = wait_for_completion_timeout(&altmode->pan_ack, 5 * HZ);
+ if (!left) {
+ dev_err(altmode->dev, "timeout waiting for altmode request ack for: %#x\n", cmd);
+ ret = -ETIMEDOUT;
+ }
+
+out_unlock:
+ mutex_unlock(&altmode->lock);
+ return ret;
+}
+
+static void pmic_glink_altmode_enable_dp(struct pmic_glink_altmode *altmode,
+ struct pmic_glink_altmode_port *port,
+ u8 mode, bool hpd_state,
+ bool hpd_irq)
+{
+ struct typec_displayport_data dp_data = {};
+ int ret;
+
+ dp_data.status = DP_STATUS_ENABLED;
+ if (hpd_state)
+ dp_data.status |= DP_STATUS_HPD_STATE;
+ if (hpd_irq)
+ dp_data.status |= DP_STATUS_IRQ_HPD;
+ dp_data.conf = DP_CONF_SET_PIN_ASSIGN(mode);
+
+ port->state.alt = &port->dp_alt;
+ port->state.data = &dp_data;
+ port->state.mode = TYPEC_MODAL_STATE(mode);
+
+ ret = typec_mux_set(port->typec_mux, &port->state);
+ if (ret)
+ dev_err(altmode->dev, "failed to switch mux to DP\n");
+}
+
+static void pmic_glink_altmode_enable_usb(struct pmic_glink_altmode *altmode,
+ struct pmic_glink_altmode_port *port)
+{
+ int ret;
+
+ port->state.alt = NULL;
+ port->state.data = NULL;
+ port->state.mode = TYPEC_STATE_USB;
+
+ ret = typec_mux_set(port->typec_mux, &port->state);
+ if (ret)
+ dev_err(altmode->dev, "failed to switch mux to USB\n");
+}
+
+static void pmic_glink_altmode_worker(struct work_struct *work)
+{
+ struct pmic_glink_altmode_port *alt_port = work_to_altmode_port(work);
+ struct pmic_glink_altmode *altmode = alt_port->altmode;
+
+ typec_switch_set(alt_port->typec_switch, alt_port->orientation);
+
+ if (alt_port->svid == USB_TYPEC_DP_SID)
+ pmic_glink_altmode_enable_dp(altmode, alt_port, alt_port->mode,
+ alt_port->hpd_state, alt_port->hpd_irq);
+ else
+ pmic_glink_altmode_enable_usb(altmode, alt_port);
+
+ if (alt_port->hpd_state)
+ drm_bridge_hpd_notify(&alt_port->bridge, connector_status_connected);
+ else
+ drm_bridge_hpd_notify(&alt_port->bridge, connector_status_disconnected);
+
+ pmic_glink_altmode_request(altmode, ALTMODE_PAN_ACK, alt_port->index);
+};
+
+static enum typec_orientation pmic_glink_altmode_orientation(unsigned int orientation)
+{
+ if (orientation == 0)
+ return TYPEC_ORIENTATION_NORMAL;
+ else if (orientation == 1)
+ return TYPEC_ORIENTATION_REVERSE;
+ else
+ return TYPEC_ORIENTATION_NONE;
+}
+
+#define SC8180X_PORT_MASK 0x000000ff
+#define SC8180X_ORIENTATION_MASK 0x0000ff00
+#define SC8180X_MUX_MASK 0x00ff0000
+#define SC8180X_MODE_MASK 0x3f000000
+#define SC8180X_HPD_STATE_MASK 0x40000000
+#define SC8180X_HPD_IRQ_MASK 0x80000000
+
+static void pmic_glink_altmode_sc8180xp_notify(struct pmic_glink_altmode *altmode,
+ const void *data, size_t len)
+{
+ struct pmic_glink_altmode_port *alt_port;
+ const struct usbc_sc8180x_notify *msg;
+ u32 notification;
+ u8 orientation;
+ u8 hpd_state;
+ u8 hpd_irq;
+ u16 svid;
+ u8 port;
+ u8 mode;
+ u8 mux;
+
+ if (len != sizeof(*msg)) {
+ dev_warn(altmode->dev, "invalid length of USBC_NOTIFY indication: %zd\n", len);
+ return;
+ }
+
+ msg = data;
+ notification = le32_to_cpu(msg->notification);
+ port = FIELD_GET(SC8180X_PORT_MASK, notification);
+ orientation = FIELD_GET(SC8180X_ORIENTATION_MASK, notification);
+ mux = FIELD_GET(SC8180X_MUX_MASK, notification);
+ mode = FIELD_GET(SC8180X_MODE_MASK, notification);
+ hpd_state = FIELD_GET(SC8180X_HPD_STATE_MASK, notification);
+ hpd_irq = FIELD_GET(SC8180X_HPD_IRQ_MASK, notification);
+
+ svid = mux == 2 ? USB_TYPEC_DP_SID : 0;
+
+ if (!altmode->ports[port].altmode) {
+ dev_dbg(altmode->dev, "notification on undefined port %d\n", port);
+ return;
+ }
+
+ alt_port = &altmode->ports[port];
+ alt_port->orientation = pmic_glink_altmode_orientation(orientation);
+ alt_port->svid = mux == 2 ? USB_TYPEC_DP_SID : 0;
+ alt_port->mode = mode;
+ alt_port->hpd_state = hpd_state;
+ alt_port->hpd_irq = hpd_irq;
+ schedule_work(&alt_port->work);
+}
+
+#define SC8280XP_DPAM_MASK 0x3f
+#define SC8280XP_HPD_STATE_MASK BIT(6)
+#define SC8280XP_HPD_IRQ_MASK BIT(7)
+
+static void pmic_glink_altmode_sc8280xp_notify(struct pmic_glink_altmode *altmode,
+ u16 svid, const void *data, size_t len)
+{
+ struct pmic_glink_altmode_port *alt_port;
+ const struct usbc_notify *notify;
+ u8 orientation;
+ u8 hpd_state;
+ u8 hpd_irq;
+ u8 mode;
+ u8 port;
+
+ if (len != sizeof(*notify)) {
+ dev_warn(altmode->dev, "invalid length USBC_NOTIFY_IND: %zd\n",
+ len);
+ return;
+ }
+
+ notify = data;
+
+ port = notify->payload[0];
+ orientation = notify->payload[1];
+ mode = FIELD_GET(SC8280XP_DPAM_MASK, notify->payload[8]) - DPAM_HPD_A;
+ hpd_state = FIELD_GET(SC8280XP_HPD_STATE_MASK, notify->payload[8]);
+ hpd_irq = FIELD_GET(SC8280XP_HPD_IRQ_MASK, notify->payload[8]);
+
+ if (!altmode->ports[port].altmode) {
+ dev_dbg(altmode->dev, "notification on undefined port %d\n", port);
+ return;
+ }
+
+ alt_port = &altmode->ports[port];
+ alt_port->orientation = pmic_glink_altmode_orientation(orientation);
+ alt_port->svid = svid;
+ alt_port->mode = mode;
+ alt_port->hpd_state = hpd_state;
+ alt_port->hpd_irq = hpd_irq;
+ schedule_work(&alt_port->work);
+}
+
+static void pmic_glink_altmode_callback(const void *data, size_t len, void *priv)
+{
+ struct pmic_glink_altmode *altmode = priv;
+ const struct pmic_glink_hdr *hdr = data;
+ u16 opcode;
+ u16 svid;
+
+ opcode = le32_to_cpu(hdr->opcode) & 0xff;
+ svid = le32_to_cpu(hdr->opcode) >> 16;
+
+ switch (opcode) {
+ case USBC_CMD_WRITE_REQ:
+ complete(&altmode->pan_ack);
+ break;
+ case USBC_NOTIFY_IND:
+ pmic_glink_altmode_sc8280xp_notify(altmode, svid, data, len);
+ break;
+ case USBC_SC8180X_NOTIFY_IND:
+ pmic_glink_altmode_sc8180xp_notify(altmode, data, len);
+ break;
+ }
+}
+
+static int pmic_glink_altmode_attach(struct drm_bridge *bridge,
+ enum drm_bridge_attach_flags flags)
+{
+ return flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR ? 0 : -EINVAL;
+}
+
+static const struct drm_bridge_funcs pmic_glink_altmode_bridge_funcs = {
+ .attach = pmic_glink_altmode_attach,
+};
+
+static void pmic_glink_altmode_put_mux(void *data)
+{
+ typec_mux_put(data);
+}
+
+static void pmic_glink_altmode_put_switch(void *data)
+{
+ typec_switch_put(data);
+}
+
+static void pmic_glink_altmode_enable_worker(struct work_struct *work)
+{
+ struct pmic_glink_altmode *altmode = work_to_altmode(work);
+ int ret;
+
+ ret = pmic_glink_altmode_request(altmode, ALTMODE_PAN_EN, 0);
+ if (ret)
+ dev_err(altmode->dev, "failed to request altmode notifications\n");
+}
+
+static void pmic_glink_altmode_pdr_notify(void *priv, int state)
+{
+ struct pmic_glink_altmode *altmode = priv;
+
+ if (state == SERVREG_SERVICE_STATE_UP)
+ schedule_work(&altmode->enable_work);
+}
+
+static const struct of_device_id pmic_glink_altmode_of_quirks[] = {
+ { .compatible = "qcom,sc8180x-pmic-glink", .data = (void *)PMIC_GLINK_OWNER_USBC },
+ {}
+};
+
+static int pmic_glink_altmode_probe(struct auxiliary_device *adev,
+ const struct auxiliary_device_id *id)
+{
+ struct pmic_glink_altmode_port *alt_port;
+ struct pmic_glink_altmode *altmode;
+ struct typec_altmode_desc mux_desc = {};
+ const struct of_device_id *match;
+ struct fwnode_handle *fwnode;
+ struct device *dev = &adev->dev;
+ u32 port;
+ int ret;
+
+ altmode = devm_kzalloc(dev, sizeof(*altmode), GFP_KERNEL);
+ if (!altmode)
+ return -ENOMEM;
+
+ altmode->dev = dev;
+
+ match = of_match_device(pmic_glink_altmode_of_quirks, dev->parent);
+ if (match)
+ altmode->owner_id = (unsigned long)match->data;
+ else
+ altmode->owner_id = PMIC_GLINK_OWNER_USBC_PAN;
+
+ INIT_WORK(&altmode->enable_work, pmic_glink_altmode_enable_worker);
+ init_completion(&altmode->pan_ack);
+ mutex_init(&altmode->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);
+ return ret;
+ }
+
+ if (port >= ARRAY_SIZE(altmode->ports)) {
+ dev_warn(dev, "invalid connector number, ignoring\n");
+ continue;
+ }
+
+ if (altmode->ports[port].altmode) {
+ dev_err(dev, "multiple connector definition for port %u\n", port);
+ return -EINVAL;
+ }
+
+ alt_port = &altmode->ports[port];
+ alt_port->altmode = altmode;
+ alt_port->index = port;
+ INIT_WORK(&alt_port->work, pmic_glink_altmode_worker);
+
+ alt_port->bridge.funcs = &pmic_glink_altmode_bridge_funcs;
+ alt_port->bridge.of_node = to_of_node(fwnode);
+ alt_port->bridge.ops = DRM_BRIDGE_OP_HPD;
+ alt_port->bridge.type = DRM_MODE_CONNECTOR_USB;
+
+ ret = devm_drm_bridge_add(dev, &alt_port->bridge);
+ if (ret)
+ return ret;
In my testing, the design of a bridge in the altmode driver made all the probe very fragile,
meaning that any device that won't probe in the full usb--pmic-glink--display driver would
prevent the whole to actually probe.
This is why drm_connector_oob_hotplug_event() was used in drivers/usb/typec/altmodes/displayport.c
and a similar design for cec where both attach to a device so there's no probe dependency.
I think there's a possible simplification here by using :
of_drm_find_bridge() instead on the endpoint target to get the last bridge,
or we could probably use the same drm_connector_oob_hotplug_event() but in any way we should
add missing pieces in drm_bridge_connector and drm/msm/dp/dp_drm.c
First in drm/msm/dp/dp_drm.c, the driver should add the of_node to the DP bridge so it can
be found from the dp controller node.
Secondly, we could add a fwnode in drm_bridge like in drm_connector and in drm_bridge_connector_init()
we could set the connector fwnode to the last bridge fwnode + the connector oob event handler.
In this case the drm_connector_oob_hotplug_event() design should work.
Anyway, I think the bindings is correct, so it's a matter of implementation to avoid delaying the
display driver probe until the pmic_glink probes entirely.
While looking closely, I don't think we can design differently except moving the bridge code
into a dummy bridge into gpu/drm/bridge, but this won't solve anything but make things even
more complex.
This design follows how generic display connector bridge is designed like in
gpu/drm/bridge/display-connector.c so it's valid.
So for the DRM Bridge part:
Acked-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Neil
Neil
+
+ alt_port->dp_alt.svid = USB_TYPEC_DP_SID;
+ alt_port->dp_alt.mode = USB_TYPEC_DP_MODE;
+ alt_port->dp_alt.active = 1;
+
+ mux_desc.svid = USB_TYPEC_DP_SID;
+ mux_desc.mode = USB_TYPEC_DP_MODE;
+ alt_port->typec_mux = fwnode_typec_mux_get(fwnode, &mux_desc);
+ if (IS_ERR(alt_port->typec_mux))
+ return dev_err_probe(dev, PTR_ERR(alt_port->typec_mux),
+ "failed to acquire mode-switch for port: %d\n",
+ port);
+
+ ret = devm_add_action_or_reset(dev, pmic_glink_altmode_put_mux,
+ alt_port->typec_mux);
+ if (ret)
+ return ret;
+
+ alt_port->typec_switch = fwnode_typec_switch_get(fwnode);
+ if (IS_ERR(alt_port->typec_switch))
+ return dev_err_probe(dev, PTR_ERR(alt_port->typec_switch),
+ "failed to acquire orientation-switch for port: %d\n",
+ port);
+
+ ret = devm_add_action_or_reset(dev, pmic_glink_altmode_put_switch,
+ alt_port->typec_switch);
+ if (ret)
+ return ret;
+ }
+
+ altmode->client = devm_pmic_glink_register_client(dev,
+ altmode->owner_id,
+ pmic_glink_altmode_callback,
+ pmic_glink_altmode_pdr_notify,
+ altmode);
+ return PTR_ERR_OR_ZERO(altmode->client);
+}
+
+static const struct auxiliary_device_id pmic_glink_altmode_id_table[] = {
+ { .name = "pmic_glink.altmode", },
+ {},
+};
+MODULE_DEVICE_TABLE(auxiliary, pmic_glink_altmode_id_table);
+
+static struct auxiliary_driver pmic_glink_altmode_driver = {
+ .name = "pmic_glink_altmode",
+ .probe = pmic_glink_altmode_probe,
+ .id_table = pmic_glink_altmode_id_table,
+};
+
+module_auxiliary_driver(pmic_glink_altmode_driver);
+
+MODULE_DESCRIPTION("Qualcomm PMIC GLINK Altmode driver");
+MODULE_LICENSE("GPL");