usb: dwc3: refactor gadget endpoint count calculation

- DWC_USB3_NUM indicates the number of Device mode single directional
  endpoints, including OUT and IN endpoint 0.

- DWC_USB3_NUM_IN_EPS indicates the maximum number of Device mode IN
  endpoints active at any time, including control endpoint 0.

It's possible to configure RTL such that DWC_USB3_NUM_EPS is equal to
DWC_USB3_NUM_IN_EPS.

dwc3-core calculates the number of OUT endpoints as DWC_USB3_NUM minus
DWC_USB3_NUM_IN_EPS. If RTL has been configured with DWC_USB3_NUM_IN_EPS
equal to DWC_USB3_NUM then dwc3-core will calculate the number of OUT
endpoints as zero.

For example a from dwc3_core_num_eps() shows:
[    1.565000]  /usb0@f01d0000: found 8 IN and 0 OUT endpoints

This patch refactors the endpoint calculation down to one variable
dwc->num_eps taking care to maintain the current mapping of endpoints for
fixed FPGA configurations as described in Table 4-7 of version 2.60a of the
DWC USB3 databook.

The endpoint mapping will then be EP-OUT, EP-IN etc, up to DWC_USB3_NUM.
If DWC_USB3_NUM is odd then OUT will take the extra endpoint.

Suggested-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

1 files changed, 2 insertions, 13 deletions

diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
index 31926dda43c9..7df45415ad70 100644
--- a/drivers/usb/dwc3/debugfs.c
+++ b/drivers/usb/dwc3/debugfs.c
@@ -822,19 +822,8 @@ static void dwc3_debugfs_create_endpoint_dirs(struct dwc3 *dwc,
 {
 	int			i;
 
-	for (i = 0; i < dwc->num_in_eps; i++) {
-		u8		epnum = (i << 1) | 1;
-		struct dwc3_ep	*dep = dwc->eps[epnum];
-
-		if (!dep)
-			continue;
-
-		dwc3_debugfs_create_endpoint_dir(dep, parent);
-	}
-
-	for (i = 0; i < dwc->num_out_eps; i++) {
-		u8		epnum = (i << 1);
-		struct dwc3_ep	*dep = dwc->eps[epnum];
+	for (i = 0; i < dwc->num_eps; i++) {
+		struct dwc3_ep	*dep = dwc->eps[i];
 
 		if (!dep)
 			continue;