backports: Add usb_find_common_endpoints()

This is needed for ath9k.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

3 files changed, 111 insertions, 0 deletions

diff --git a/backport/backport-include/linux/usb.h b/backport/backport-include/linux/usb.h
new file mode 100644
index 00000000..acb5b2ee
--- /dev/null
+++ b/backport/backport-include/linux/usb.h
@@ -0,0 +1,16 @@
+#ifndef __BACKPORT_LINUX_USB_H
+#define __BACKPORT_LINUX_USB_H
+#include_next <linux/usb.h>
+#include <linux/version.h>
+
+#if LINUX_VERSION_IS_LESS(4,12,0)
+#define usb_find_common_endpoints LINUX_BACKPORT(usb_find_common_endpoints)
+int __must_check
+usb_find_common_endpoints(struct usb_host_interface *alt,
+		struct usb_endpoint_descriptor **bulk_in,
+		struct usb_endpoint_descriptor **bulk_out,
+		struct usb_endpoint_descriptor **int_in,
+		struct usb_endpoint_descriptor **int_out);
+#endif /* < 4.12 */
+
+#endif /* __BACKPORT_LINUX_USB_H */
diff --git a/backport/compat/Makefile b/backport/compat/Makefile
index b9f1dee9..a1be9e83 100644
--- a/backport/compat/Makefile
+++ b/backport/compat/Makefile
@@ -13,6 +13,7 @@ compat-$(CPTCFG_KERNEL_4_7) += backport-4.7.o
 compat-$(CPTCFG_KERNEL_4_8) += backport-4.8.o
 compat-$(CPTCFG_KERNEL_4_10) += backport-4.10.o
 compat-$(CPTCFG_KERNEL_4_11) += backport-4.11.o
+compat-$(CPTCFG_KERNEL_4_12) += backport-4.12.o
 compat-$(CPTCFG_KERNEL_4_18) += backport-4.18.o
 compat-$(CPTCFG_KERNEL_5_2) += backport-5.2.o backport-genetlink.o
 compat-$(CPTCFG_KERNEL_5_3) += backport-5.3.o
diff --git a/backport/compat/backport-4.12.c b/backport/compat/backport-4.12.c
new file mode 100644
index 00000000..1307a69e
--- /dev/null
+++ b/backport/compat/backport-4.12.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/usb.h>
+#include <linux/usb/ch9.h>
+
+static bool match_endpoint(struct usb_endpoint_descriptor *epd,
+		struct usb_endpoint_descriptor **bulk_in,
+		struct usb_endpoint_descriptor **bulk_out,
+		struct usb_endpoint_descriptor **int_in,
+		struct usb_endpoint_descriptor **int_out)
+{
+	switch (usb_endpoint_type(epd)) {
+	case USB_ENDPOINT_XFER_BULK:
+		if (usb_endpoint_dir_in(epd)) {
+			if (bulk_in && !*bulk_in) {
+				*bulk_in = epd;
+				break;
+			}
+		} else {
+			if (bulk_out && !*bulk_out) {
+				*bulk_out = epd;
+				break;
+			}
+		}
+
+		return false;
+	case USB_ENDPOINT_XFER_INT:
+		if (usb_endpoint_dir_in(epd)) {
+			if (int_in && !*int_in) {
+				*int_in = epd;
+				break;
+			}
+		} else {
+			if (int_out && !*int_out) {
+				*int_out = epd;
+				break;
+			}
+		}
+
+		return false;
+	default:
+		return false;
+	}
+
+	return (!bulk_in || *bulk_in) && (!bulk_out || *bulk_out) &&
+			(!int_in || *int_in) && (!int_out || *int_out);
+}
+
+/**
+ * usb_find_common_endpoints() -- look up common endpoint descriptors
+ * @alt:	alternate setting to search
+ * @bulk_in:	pointer to descriptor pointer, or NULL
+ * @bulk_out:	pointer to descriptor pointer, or NULL
+ * @int_in:	pointer to descriptor pointer, or NULL
+ * @int_out:	pointer to descriptor pointer, or NULL
+ *
+ * Search the alternate setting's endpoint descriptors for the first bulk-in,
+ * bulk-out, interrupt-in and interrupt-out endpoints and return them in the
+ * provided pointers (unless they are NULL).
+ *
+ * If a requested endpoint is not found, the corresponding pointer is set to
+ * NULL.
+ *
+ * Return: Zero if all requested descriptors were found, or -ENXIO otherwise.
+ */
+int usb_find_common_endpoints(struct usb_host_interface *alt,
+		struct usb_endpoint_descriptor **bulk_in,
+		struct usb_endpoint_descriptor **bulk_out,
+		struct usb_endpoint_descriptor **int_in,
+		struct usb_endpoint_descriptor **int_out)
+{
+	struct usb_endpoint_descriptor *epd;
+	int i;
+
+	if (bulk_in)
+		*bulk_in = NULL;
+	if (bulk_out)
+		*bulk_out = NULL;
+	if (int_in)
+		*int_in = NULL;
+	if (int_out)
+		*int_out = NULL;
+
+	for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
+		epd = &alt->endpoint[i].desc;
+
+		if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
+			return 0;
+	}
+
+	return -ENXIO;
+}
+EXPORT_SYMBOL_GPL(usb_find_common_endpoints);