greybus: es2: get cport count from apb1 usb device

Use the control request REQUEST_CPORT_COUNT in order to get the number of
CPorts supported by the UniPro IP.

Signed-off-by: Fabien Parent <fparent@baylibre.com>
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>

diff --git a/drivers/staging/greybus/es2.c b/drivers/staging/greybus/es2.c
index 909ca6acae1c765d175df12e5f572a9529a3c807..13605b8f873b552978f7dea3ce5a914842dd1c7d 100644 (file)
--- a/drivers/staging/greybus/es2.c
+++ b/drivers/staging/greybus/es2.c
@@ -33,9 +33,6 @@ static struct dentry *apb1_log_enable_dentry;
 static struct task_struct *apb1_log_task;
 static DEFINE_KFIFO(apb1_log_fifo, char, APB1_LOG_SIZE);
 
-/* Number of cport present on USB bridge */
-#define CPORT_COUNT            44
-
 /* Number of bulk in and bulk out couple */
 #define NUM_BULKS              7
 
@@ -60,6 +57,9 @@ static DEFINE_KFIFO(apb1_log_fifo, char, APB1_LOG_SIZE);
 /* vendor request to map a cport to bulk in and bulk out endpoints */
 #define REQUEST_EP_MAPPING     0x03
 
+/* vendor request to get the number of cports available */
+#define REQUEST_CPORT_COUNT    0x04
+
 /*
  * @endpoint: bulk in endpoint for CPort data
  * @urb: array of urbs for the CPort in messages
@@ -636,6 +636,39 @@ static const struct file_operations apb1_log_enable_fops = {
        .write  = apb1_log_enable_write,
 };
 
+static int apb1_get_cport_count(struct usb_device *udev)
+{
+       int retval;
+       __le16 *cport_count;
+
+       cport_count = kmalloc(sizeof(*cport_count), GFP_KERNEL);
+       if (!cport_count)
+               return -ENOMEM;
+
+       retval = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
+                                REQUEST_CPORT_COUNT,
+                                USB_DIR_IN | USB_TYPE_VENDOR |
+                                USB_RECIP_INTERFACE, 0, 0, cport_count,
+                                sizeof(*cport_count), ES1_TIMEOUT);
+       if (retval < 0) {
+               dev_err(&udev->dev, "Cannot retrieve CPort count: %d\n",
+                       retval);
+               goto out;
+       }
+
+       retval = le16_to_cpu(*cport_count);
+
+       /* We need to fit a CPort ID in one byte of a message header */
+       if (retval > U8_MAX) {
+               retval = U8_MAX;
+               dev_warn(&udev->dev, "Limiting number of CPorts to U8_MAX\n");
+       }
+
+out:
+       kfree(cport_count);
+       return retval;
+}
+
 /*
  * The ES1 USB Bridge device contains 4 endpoints
  * 1 Control - usual USB stuff + AP -> SVC messages
@@ -655,14 +688,20 @@ static int ap_probe(struct usb_interface *interface,
        int bulk_out = 0;
        int retval = -ENOMEM;
        int i;
-
-       /* We need to fit a CPort ID in one byte of a message header */
-       BUILD_BUG_ON(CPORT_ID_MAX > U8_MAX);
+       int num_cports;
 
        udev = usb_get_dev(interface_to_usbdev(interface));
 
+       num_cports = apb1_get_cport_count(udev);
+       if (num_cports < 0) {
+               usb_put_dev(udev);
+               dev_err(&udev->dev, "Cannot retrieve CPort count: %d\n",
+                       num_cports);
+               return num_cports;
+       }
+
        hd = greybus_create_hd(&es1_driver, &udev->dev, ES1_GBUF_MSG_SIZE_MAX,
-                              CPORT_COUNT);
+                              num_cports);
        if (IS_ERR(hd)) {
                usb_put_dev(udev);
                return PTR_ERR(hd);