Re: [PATCH v8 1/6] usb: Add support for Intel LJCA device

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On 11.05.23 19:58, Ye Xiang wrote:
Implements the USB part of Intel USB-I2C/GPIO/SPI adapter device
named "La Jolla Cove Adapter" (LJCA).

The communication between the various LJCA module drivers and the
hardware will be muxed/demuxed by this driver. Three modules (
I2C, GPIO, and SPI) are supported currently.

Each sub-module of LJCA device is identified by type field within
the LJCA message header.


Hi,

I am terribly sorry to come up with issues after so many iterations,
but I am really afraid there are issues left.

The minimum code in ASL that covers this board is
Scope (\_SB.PCI0.DWC3.RHUB.HS01)
     {
         Device (GPIO)
         {
             Name (_ADR, Zero)
             Name (_STA, 0x0F)
         }

         Device (I2C)
         {
             Name (_ADR, One)
             Name (_STA, 0x0F)
         }

         Device (SPI)
         {
             Name (_ADR, 0x02)
             Name (_STA, 0x0F)
         }
     }

Signed-off-by: Ye Xiang <xiang.ye@xxxxxxxxx>
---

+
+/* MNG stub commands */
+enum ljca_mng_cmd {
+	LJCA_MNG_GET_VERSION = 1,
+	LJCA_MNG_RESET_NOTIFY,
+	LJCA_MNG_RESET,
+	LJCA_MNG_ENUM_GPIO,
+	LJCA_MNG_ENUM_I2C,
+	LJCA_MNG_POWER_STATE_CHANGE,
+	LJCA_MNG_SET_DFU_MODE,
+	LJCA_MNG_ENUM_SPI,
+};
+
+/* DIAG commands */
+enum ljca_diag_cmd {
+	LJCA_DIAG_GET_STATE = 1,
+	LJCA_DIAG_GET_STATISTIC,
+	LJCA_DIAG_SET_TRACE_LEVEL,
+	LJCA_DIAG_SET_ECHO_MODE,
+	LJCA_DIAG_GET_FW_LOG,
+	LJCA_DIAG_GET_FW_COREDUMP,
+	LJCA_DIAG_TRIGGER_WDT,
+	LJCA_DIAG_TRIGGER_FAULT,
+	LJCA_DIAG_FEED_WDT,
+	LJCA_DIAG_GET_SECURE_STATE,
+};

Should those really be enum? They just happen
to be nummerically dense.


+static int ljca_parse(struct ljca_dev *dev, struct ljca_msg *header)
+{
+	struct ljca_stub *stub;
+	unsigned int *ibuf_len;
+	u8 *ibuf;
+
+	stub = ljca_stub_find(dev, header->type);
+	if (IS_ERR(stub))
+		return PTR_ERR(stub);
+
+	if (!(header->flags & LJCA_ACK_FLAG)) {
+		ljca_stub_notify(stub, header->cmd, header->data, header->len);
+		return 0;
+	}

First you ack ...

+
+	if (stub->cur_cmd != header->cmd) {
+		dev_err(&dev->intf->dev, "header and stub current command mismatch (%x vs %x)\n",
+			header->cmd, stub->cur_cmd);
+		return -EINVAL;
+	}

... then you check whether this is for the correct command?

+
+	ibuf_len = READ_ONCE(stub->ipacket.ibuf_len);
+	ibuf = READ_ONCE(stub->ipacket.ibuf);

This races against stub_write(). Yes, every value now is consistent
within this function. But that does not solve the issue. The pair needs
to be consistent. You need to rule out that you are reading a different
length and buffer location. I am afraid this needs a spinlock.

+
+	if (ibuf && ibuf_len) {
+		unsigned int newlen;
+
+		newlen = min_t(unsigned int, header->len, *ibuf_len);
+
+		*ibuf_len = newlen;
+		memcpy(ibuf, header->data, newlen);
+	}
+
+	stub->acked = true;
+	wake_up(&dev->ack_wq);
+
+	return 0;
+}
+
+static int ljca_stub_write(struct ljca_stub *stub, u8 cmd, const void *obuf, unsigned int obuf_len,
+			   void *ibuf, unsigned int *ibuf_len, bool wait_ack, unsigned long timeout)
+{
+	struct ljca_dev *dev = usb_get_intfdata(stub->intf);
+	u8 flags = LJCA_CMPL_FLAG;
+	struct ljca_msg *header;
+	unsigned int msg_len = sizeof(*header) + obuf_len;
+	int actual;
+	int ret;
+
+	if (msg_len > LJCA_MAX_PACKET_SIZE)
+		return -EINVAL;
+
+	if (wait_ack)
+		flags |= LJCA_ACK_FLAG;
+
+	header = kmalloc(msg_len, GFP_KERNEL);
+	if (!header)
+		return -ENOMEM;

Do you really want to first set a flag, then error out?

+	header->type = stub->type;
+	header->cmd = cmd;
+	header->flags = flags;
+	header->len = obuf_len;
+
+	if (obuf)
+		memcpy(header->data, obuf, obuf_len);
+
+	dev_dbg(&dev->intf->dev, "send: type:%d cmd:%d flags:%d len:%d\n", header->type,
+		header->cmd, header->flags, header->len);
+
+	usb_autopm_get_interface(dev->intf);
+	if (!dev->started) {
+		kfree(header);
+		ret = -ENODEV;

Again, the flag remains set.

+		goto error_put;
+	}
+
+	mutex_lock(&dev->mutex);
+	stub->cur_cmd = cmd;
+	stub->ipacket.ibuf = ibuf;
+	stub->ipacket.ibuf_len = ibuf_len;
+	stub->acked = false;
+	ret = usb_bulk_msg(interface_to_usbdev(dev->intf),
+			   usb_sndbulkpipe(interface_to_usbdev(dev->intf), dev->out_ep), header,
+			   msg_len, &actual, LJCA_USB_WRITE_TIMEOUT_MS);
+	kfree(header);
+	if (ret) {
+		dev_err(&dev->intf->dev, "bridge write failed ret:%d\n", ret);
+		goto error_unlock;
+	}
+
+	if (actual != msg_len) {
+		dev_err(&dev->intf->dev, "bridge write length mismatch (%d vs %d)\n", msg_len,
+			actual);
+		ret = -EINVAL;
+		goto error_unlock;
+	}
+
+	if (wait_ack) {
+		ret = wait_event_timeout(dev->ack_wq, stub->acked, msecs_to_jiffies(timeout));
+		if (!ret) {
+			dev_err(&dev->intf->dev, "acked wait timeout\n");
+			ret = -ETIMEDOUT;
+			goto error_unlock;
+		}
+	}
+
+	ret = 0;
+error_unlock:
+	stub->ipacket.ibuf = NULL;
+	stub->ipacket.ibuf_len = NULL;
+	mutex_unlock(&dev->mutex);
+error_put:
+	usb_autopm_put_interface(dev->intf);
+
+	return ret;
+}
+

[..]
+static int ljca_start(struct ljca_dev *dev)
+{
+	int ret;
+
+	usb_fill_bulk_urb(dev->in_urb, interface_to_usbdev(dev->intf),
+			  usb_rcvbulkpipe(interface_to_usbdev(dev->intf), dev->in_ep), dev->ibuf,
+			  dev->ibuf_len, ljca_read_complete, dev);
+
+	ret = usb_submit_urb(dev->in_urb, GFP_KERNEL);
+	if (ret) {
+		dev_err(&dev->intf->dev, "failed submitting read urb, error %d\n", ret);
+		return ret;
+	}
+
+	mutex_lock(&dev->mutex);
+	dev->started = true;
+	mutex_unlock(&dev->mutex);

Why do you take a mutex here? Either this function cannot race with anything else,
or you set the flag too late.

+
+	return 0;
+}
+

+#ifdef CONFIG_ACPI
+static void ljca_aux_dev_acpi_bind(struct ljca_dev *dev, struct auxiliary_device *auxdev,
+				   unsigned int adr)
+{
+	struct acpi_device *parent;
+	struct acpi_device *adev = NULL;
+
+	/* new auxiliary device bind to acpi device */
+	parent = ACPI_COMPANION(&dev->intf->dev);
+	if (!parent)
+		return;
+
+	adev = acpi_find_child_device(parent, adr, false);
+	ACPI_COMPANION_SET(&auxdev->dev, adev ?: parent);
+}
+#else
+static void ljca_aux_dev_acpi_bind(struct ljca_dev *dev, struct auxiliary_device *auxdev,
+				   unsigned int adr)
+{
+}
+#endif
+
+static int ljca_add_aux_dev(struct ljca_dev *dev, char *name, u8 type, u8 id, u8 adr, void *data,
+			    unsigned int len)
+{
+	struct auxiliary_device *auxdev;
+	struct ljca *ljca;
+	int ret;
+
+	if (dev->ljca_count >= ARRAY_SIZE(dev->ljcas))
+		return -EINVAL;
+
+	ljca = kzalloc(sizeof(*ljca), GFP_KERNEL);
+	if (!ljca)
+		return -ENOMEM;
+
+	ljca->type = type;
+	ljca->id = id;
+	ljca->dev = dev;
+
+	auxdev = &ljca->auxdev;
+	auxdev->name = name;
+	auxdev->id = id;
+	auxdev->dev.platform_data = kmemdup(data, len, GFP_KERNEL);
+	if (!auxdev->dev.platform_data)
+		return -ENOMEM;

memory leak of struct ljca *ljca

+
+	auxdev->dev.parent = &dev->intf->dev;
+	auxdev->dev.release = ljca_aux_release;

	Regards
		Oliver




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