[PATCH v4 11/43] usb: gadget: composite: generate old descs for compatibility

[Robert Baldyga]

For now we generate descriptor arrays for each speed as it is done by old
API functions, to allow use mixed new and old API based functions in single
configurations.

This will be removed after complete switch to new API.

Signed-off-by: Robert Baldyga <r.baldyga@xxxxxxxxxxx>
---
 drivers/usb/gadget/composite.c | 175 +++++++++++++++++++++++++++++++++++++++++
 include/linux/usb/composite.h  |   2 +
 2 files changed, 177 insertions(+)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 4f5556b..c34725b 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -2254,6 +2254,30 @@ void composite_free_vendor_descs(struct usb_composite_dev *cdev)
 }
 EXPORT_SYMBOL_GPL(composite_free_vendor_descs);
 
+/**
+ * composite_free_old_descs - for all functions implementing new API free old
+ *	descriptors arrays.
+ * @cdev: composite device
+ */
+void composite_free_old_descs(struct usb_composite_dev *cdev)
+{
+	struct usb_configuration *c;
+	struct usb_function *f;
+
+	list_for_each_entry(c, &cdev->configs, list)
+		list_for_each_entry(f, &c->functions, list) {
+			if (!usb_function_is_new_api(f))
+				continue;
+			kfree(f->fs_descriptors);
+			kfree(f->hs_descriptors);
+			kfree(f->ss_descriptors);
+			f->fs_descriptors = NULL;
+			f->hs_descriptors = NULL;
+			f->ss_descriptors = NULL;
+		}
+}
+EXPORT_SYMBOL_GPL(composite_free_old_descs);
+
 static void __composite_unbind(struct usb_gadget *gadget, bool unbind_driver)
 {
 	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
@@ -2265,6 +2289,7 @@ static void __composite_unbind(struct usb_gadget *gadget, bool unbind_driver)
 	 */
 	WARN_ON(cdev->config);
 
+	composite_free_old_descs(cdev);
 	composite_free_vendor_descs(cdev);
 	composite_free_descs(cdev);
 
@@ -2592,6 +2617,152 @@ int composite_prep_vendor_descs(struct usb_composite_dev *cdev)
 }
 EXPORT_SYMBOL_GPL(composite_prep_vendor_descs);
 
+/*
+ * function_add_desc() - Add given descriptor to descriptor arrays for
+ *	each supported speed, in proper version for each speed.
+ *
+ * @f - USB function
+ * @idx - pointer to index of descriptor in fs and hs array
+ * @idx_ss - pointer to index of descriptor in ss array
+ * @fs - descriptor for FS
+ * @hs - descriptor for HS
+ * @ss - descriptor for SS
+ *
+ * Indexes are automatically incremented.
+ *
+ * This function will be removed after converting all USB functions
+ * in kernel to new API.
+ */
+static inline void function_add_desc(struct usb_function *f,
+		int *idx, int *idx_ss,
+		struct usb_descriptor_header *fs,
+		struct usb_descriptor_header *hs,
+		struct usb_descriptor_header *ss) {
+	if (f->config->fullspeed)
+		f->fs_descriptors[*idx] = fs;
+	if (f->config->highspeed)
+		f->hs_descriptors[*idx] = hs;
+	if (f->config->superspeed)
+		f->ss_descriptors[*idx_ss] = ss;
+	++(*idx);
+	++(*idx_ss);
+}
+
+/*
+ * function_generate_old_descs() - generate descriptors array for each speed
+ *
+ * Allocate arrays of needed size and assign to them USB descriptors.
+ *
+ * This is temporary solution allowing coexistence to both old and new function
+ * API. It will be removed after converting all functions in kernel to new API.
+ */
+static int function_generate_old_descs(struct usb_function *f)
+{
+	struct usb_composite_intf *intf;
+	struct usb_composite_altset *alt;
+	struct usb_composite_ep *ep;
+	struct usb_composite_vendor_desc *vd;
+	int cnt, eps, i, a, e, idx, idx_ss;
+
+	cnt = f->descs->vendor_descs_num;
+	eps = 0;
+
+	for (i = 0; i < f->descs->intfs_num; ++i) {
+		intf = f->descs->intfs[i];
+		for (a = 0; a < intf->altsets_num; ++a) {
+			alt = intf->altsets[a];
+			cnt += alt->vendor_descs_num + 1;
+			eps += alt->eps_num;
+			for (e = 0; e < alt->eps_num; ++e)
+				cnt += alt->eps[e]->vendor_descs_num + 1;
+		}
+	}
+
+	if (f->config->fullspeed) {
+		f->fs_descriptors = kzalloc((cnt + 1) *
+				sizeof(*f->fs_descriptors), GFP_KERNEL);
+		if (!f->fs_descriptors)
+			return -ENOMEM;
+	}
+	if (f->config->highspeed) {
+		f->hs_descriptors = kzalloc((cnt + 1) *
+				sizeof(*f->hs_descriptors), GFP_KERNEL);
+		if (!f->hs_descriptors)
+			goto err;
+	}
+	if (f->config->superspeed) {
+		f->ss_descriptors = kzalloc((cnt + eps + 1) *
+				sizeof(*f->ss_descriptors), GFP_KERNEL);
+		if (!f->ss_descriptors)
+			goto err;
+	}
+
+	idx = 0;
+	idx_ss = 0;
+	list_for_each_entry(vd, &f->descs->vendor_descs, list)
+		function_add_desc(f, &idx, &idx_ss,
+				vd->desc, vd->desc, vd->desc);
+	for (i = 0; i < f->descs->intfs_num; ++i) {
+		intf = f->descs->intfs[i];
+		for (a = 0; a < intf->altsets_num; ++a) {
+			alt = intf->altsets[a];
+			function_add_desc(f, &idx, &idx_ss, alt->alt.header,
+					alt->alt.header, alt->alt.header);
+			list_for_each_entry(vd, &alt->vendor_descs, list)
+				function_add_desc(f, &idx, &idx_ss,
+						vd->desc, vd->desc, vd->desc);
+			for (e = 0; e < alt->eps_num; ++e) {
+				ep = alt->eps[e];
+				function_add_desc(f, &idx, &idx_ss,
+						ep->fs.header, ep->hs.header,
+						ep->ss.header);
+				if (f->config->superspeed)
+					f->ss_descriptors[idx_ss++] =
+							ep->ss_comp.header;
+				list_for_each_entry(vd,
+						&ep->vendor_descs, list)
+					function_add_desc(f, &idx, &idx_ss,
+						vd->desc, vd->desc, vd->desc);
+			}
+		}
+	}
+
+	return 0;
+
+err:
+	kfree(f->ss_descriptors);
+	f->ss_descriptors = NULL;
+	kfree(f->hs_descriptors);
+	f->hs_descriptors = NULL;
+	kfree(f->fs_descriptors);
+	f->fs_descriptors = NULL;
+
+	return -ENOMEM;
+}
+
+/*
+ * composite_generate_old_descs() - generate descriptors arrays for each
+ *	function in each configuraion
+ */
+int composite_generate_old_descs(struct usb_composite_dev *cdev)
+{
+	struct usb_configuration *c;
+	struct usb_function *f;
+	int ret;
+
+	list_for_each_entry(c, &cdev->configs, list)
+		list_for_each_entry(f, &c->functions, list) {
+			if (!usb_function_is_new_api(f))
+				continue;
+			ret = function_generate_old_descs(f);
+			if (ret)
+				return ret;
+		}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(composite_generate_old_descs);
+
 static int composite_bind(struct usb_gadget *gadget,
 		struct usb_gadget_driver *gdriver)
 {
@@ -2626,6 +2797,10 @@ static int composite_bind(struct usb_gadget *gadget,
 	if (status < 0)
 		goto fail;
 
+	status = composite_generate_old_descs(cdev);
+	if (status < 0)
+		goto fail;
+
 	if (cdev->use_os_string) {
 		status = composite_os_desc_req_prepare(cdev, gadget->ep0);
 		if (status)
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index 0db473f..e985f3a 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -600,9 +600,11 @@ extern int composite_os_desc_req_prepare(struct usb_composite_dev *cdev,
 void composite_dev_cleanup(struct usb_composite_dev *cdev);
 
 int composite_prep_vendor_descs(struct usb_composite_dev *cdev);
+int composite_generate_old_descs(struct usb_composite_dev *cdev);
 
 void composite_free_descs(struct usb_composite_dev *cdev);
 void composite_free_vendor_descs(struct usb_composite_dev *cdev);
+void composite_free_old_descs(struct usb_composite_dev *cdev);
 
 static inline struct usb_composite_driver *to_cdriver(
 		struct usb_gadget_driver *gdrv)
-- 
1.9.1