Mailing List Archive

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

Signed-off-by: Pavan Holla <pholla@chromium.org>
---
drivers/platform/chrome/Kconfig | 14 ++
drivers/platform/chrome/Makefile | 1 +
drivers/platform/chrome/cros_ec_ucsi.c | 247 +++++++++++++++++++++++++
include/linux/platform_data/cros_ec_commands.h | 19 ++
4 files changed, 281 insertions(+)

diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 7a83346bfa53..67ab79a6815b 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -238,6 +238,20 @@ config CROS_EC_TYPEC
To compile this driver as a module, choose M here: the module will be
called cros-ec-typec.

+config CROS_EC_UCSI
+ tristate "UCSI Driver for ChromeOS EC"
+ depends on MFD_CROS_EC_DEV
+ depends on CROS_USBPD_NOTIFY
+ depends on TYPEC_UCSI
+ 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 CROS_HPS_I2C
tristate "ChromeOS HPS device"
depends on HID && I2C && PM
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 2dcc6ccc2302..85964e165a70 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_CROS_EC_UART) += cros_ec_uart.o
cros_ec_lpcs-objs := cros_ec_lpc.o cros_ec_lpc_mec.o
cros-ec-typec-objs := cros_ec_typec.o cros_typec_vdm.o
obj-$(CONFIG_CROS_EC_TYPEC) += cros-ec-typec.o
+obj-$(CONFIG_CROS_EC_UCSI) += cros_ec_ucsi.o
obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpcs.o
obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o cros_ec_trace.o
obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o
diff --git a/drivers/platform/chrome/cros_ec_ucsi.c b/drivers/platform/chrome/cros_ec_ucsi.c
new file mode 100644
index 000000000000..9fee300a3d93
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_ucsi.c
@@ -0,0 +1,247 @@
+// 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/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/usb/ucsi.h>
+#include <linux/wait.h>
+
+#define DRV_NAME "cros-ec-ucsi"
+
+#define MAX_EC_DATA_SIZE 256
+#define WRITE_TMO_MS 500
+
+#define COMMAND_PENDING 1
+#define ACK_PENDING 2
+
+#define UCSI_COMMAND(_cmd_) ((_cmd_) & 0xff)
+#define UCSI_ACK_CC_CI 0x04
+
+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_async_write(struct ucsi *ucsi, unsigned int offset,
+ const void *val, size_t val_len)
+{
+ struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
+ uint8_t ec_buffer[MAX_EC_DATA_SIZE + sizeof(struct ec_params_ucsi_ppm_set)];
+ struct ec_params_ucsi_ppm_set *req = (struct ec_params_ucsi_ppm_set *)ec_buffer;
+ int ret = 0;
+
+ if (val_len > MAX_EC_DATA_SIZE) {
+ dev_err(udata->dev, "Can't write %zu bytes. Too big.", val_len);
+ return -EINVAL;
+ }
+
+ memset(req, 0, sizeof(ec_buffer));
+ req->offset = offset;
+ memcpy(req->data, val, val_len);
+ ret = cros_ec_cmd(udata->ec, 0, EC_CMD_UCSI_PPM_SET,
+ req, sizeof(struct ec_params_ucsi_ppm_set) + val_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_write(struct ucsi *ucsi, unsigned int offset,
+ const void *val, size_t val_len)
+{
+ struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
+ bool ack = UCSI_COMMAND(*(u64 *)val) == 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_write(ucsi, offset, val, val_len);
+ 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 = cros_ucsi_read,
+ .async_write = cros_ucsi_async_write,
+ .sync_write = cros_ucsi_sync_write,
+};
+
+static void cros_ucsi_work(struct work_struct *work)
+{
+ struct cros_ucsi_data *udata = container_of(work, struct cros_ucsi_data, work);
+ u32 cci;
+ int ret;
+
+ ret = cros_ucsi_read(udata->ucsi, UCSI_CCI, &cci, sizeof(cci));
+ if (ret)
+ return;
+
+ if (UCSI_CCI_CONNECTOR(cci))
+ ucsi_connector_change(udata->ucsi, UCSI_CCI_CONNECTOR(cci));
+
+ if (cci & UCSI_CCI_ACK_COMPLETE && test_bit(ACK_PENDING, &udata->flags))
+ complete(&udata->complete);
+ if (cci & UCSI_CCI_COMMAND_COMPLETE &&
+ test_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 int cros_ucsi_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct cros_ucsi_data *udata;
+ int ret;
+
+ udata = devm_kzalloc(dev, sizeof(*udata), GFP_KERNEL);
+ if (!udata)
+ return -ENOMEM;
+
+ udata->dev = dev;
+
+ udata->ec = ((struct cros_ec_dev *) dev_get_drvdata(pdev->dev.parent))->ec_dev;
+ if (!udata->ec) {
+ dev_err(dev, "couldn't find parent EC device\n");
+ return -ENODEV;
+ }
+
+ platform_set_drvdata(pdev, udata);
+
+ INIT_WORK(&udata->work, cros_ucsi_work);
+ init_completion(&udata->complete);
+
+ udata->ucsi = ucsi_create(udata->dev, &cros_ucsi_ops);
+ if (IS_ERR(udata->ucsi)) {
+ dev_err(dev, "failed to allocate UCSI instance\n");
+ return PTR_ERR(udata->ucsi);
+ }
+
+ ucsi_set_drvdata(udata->ucsi, udata);
+
+ ret = ucsi_register(udata->ucsi);
+ if (ret) {
+ ucsi_destroy(udata->ucsi);
+ udata->ucsi = NULL;
+ return ret;
+ }
+
+ udata->nb.notifier_call = cros_ucsi_event;
+ ret = cros_usbpd_register_notify(&udata->nb);
+ return ret;
+}
+
+static int cros_ucsi_remove(struct platform_device *dev)
+{
+ struct cros_ucsi_data *udata = platform_get_drvdata(dev);
+
+ if (udata->ucsi) {
+ ucsi_unregister(udata->ucsi);
+ ucsi_destroy(udata->ucsi);
+ udata->ucsi = NULL;
+ }
+ return 0;
+}
+
+static int cros_ucsi_suspend(struct device *dev)
+{
+ struct cros_ucsi_data *udata = dev_get_drvdata(dev);
+
+ cancel_work_sync(&udata->work);
+
+ return 0;
+}
+
+static int 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 struct platform_driver cros_ucsi_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ .pm = &cros_ucsi_pm_ops,
+ },
+ .probe = cros_ucsi_probe,
+ .remove = cros_ucsi_remove,
+};
+
+module_platform_driver(cros_ucsi_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("UCSI driver for ChromeOS EC.");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/platform_data/cros_ec_commands.h b/include/linux/platform_data/cros_ec_commands.h
index ecc47d5fe239..39f6f54bbe4c 100644
--- a/include/linux/platform_data/cros_ec_commands.h
+++ b/include/linux/platform_data/cros_ec_commands.h
@@ -4933,6 +4933,7 @@ struct ec_response_pd_status {
#define PD_EVENT_POWER_CHANGE BIT(1)
#define PD_EVENT_IDENTITY_RECEIVED BIT(2)
#define PD_EVENT_DATA_SWAP BIT(3)
+#define PD_EVENT_PPM BIT(5)
struct ec_response_host_event_status {
uint32_t status; /* PD MCU host event status */
} __ec_align4;
@@ -5994,6 +5995,24 @@ struct ec_response_typec_vdm_response {

#undef VDO_MAX_SIZE

+/*
+ * Read/write interface for UCSI OPM <-> PPM communication.
+ */
+#define EC_CMD_UCSI_PPM_SET 0x0140
+
+/* The data size is stored in the host command protocol header. */
+struct ec_params_ucsi_ppm_set {
+ uint16_t offset;
+ uint8_t data[];
+} __ec_align2;
+
+#define EC_CMD_UCSI_PPM_GET 0x0141
+
+struct ec_params_ucsi_ppm_get {
+ uint16_t offset;
+ uint8_t size;
+} __ec_align2;
+
/*****************************************************************************/
/* The command range 0x200-0x2FF is reserved for Rotor. */


--
2.44.0.396.g6e790dbe36-goog