usb: xhci-mtk: add some schedule error number

[ Upstream commit ccda8c224c0701caac007311d06a2de9543a7590 ]

This is used to provide more information about which case
causes bandwidth schedule failure.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/9771f44093053b581e9c4be4b7fb68d9fcecad08.1615170625.git.chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 548011957d1d ("usb: xhci-mtk: relax TT periodic bandwidth allocation")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index 9a9685f749405c7d4fbde12bc7e30ae96d4fa18e..a6ec75bf2defaf7e96ac9260e5c4ea6f73e876ac 100644 (file)
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -25,6 +25,13 @@
  */
 #define TT_MICROFRAMES_MAX 9
 
+/* schedule error type */
+#define ESCH_SS_Y6             1001
+#define ESCH_SS_OVERLAP                1002
+#define ESCH_CS_OVERFLOW       1003
+#define ESCH_BW_OVERFLOW       1004
+#define ESCH_FIXME             1005
+
 /* mtk scheduler bitmasks */
 #define EP_BPKTS(p)    ((p) & 0x7f)
 #define EP_BCSCOUNT(p) (((p) & 0x7) << 8)
@@ -32,6 +39,24 @@
 #define EP_BOFFSET(p)  ((p) & 0x3fff)
 #define EP_BREPEAT(p)  (((p) & 0x7fff) << 16)
 
+static char *sch_error_string(int err_num)
+{
+       switch (err_num) {
+       case ESCH_SS_Y6:
+               return "Can't schedule Start-Split in Y6";
+       case ESCH_SS_OVERLAP:
+               return "Can't find a suitable Start-Split location";
+       case ESCH_CS_OVERFLOW:
+               return "The last Complete-Split is greater than 7";
+       case ESCH_BW_OVERFLOW:
+               return "Bandwidth exceeds the maximum limit";
+       case ESCH_FIXME:
+               return "FIXME, to be resolved";
+       default:
+               return "Unknown";
+       }
+}
+
 static int is_fs_or_ls(enum usb_device_speed speed)
 {
        return speed == USB_SPEED_FULL || speed == USB_SPEED_LOW;
@@ -395,7 +420,7 @@ static int check_fs_bus_bw(struct mu3h_sch_ep_info *sch_ep, int offset)
                for (j = 0; j < sch_ep->cs_count; j++) {
                        tmp = tt->fs_bus_bw[base + j] + sch_ep->bw_cost_per_microframe;
                        if (tmp > FS_PAYLOAD_MAX)
-                               return -ERANGE;
+                               return -ESCH_BW_OVERFLOW;
                }
        }
 
@@ -421,11 +446,11 @@ static int check_sch_tt(struct usb_device *udev,
                 * must never schedule Start-Split in Y6
                 */
                if (!(start_ss == 7 || last_ss < 6))
-                       return -ERANGE;
+                       return -ESCH_SS_Y6;
 
                for (i = 0; i < sch_ep->cs_count; i++)
                        if (test_bit(offset + i, tt->ss_bit_map))
-                               return -ERANGE;
+                               return -ESCH_SS_OVERLAP;
 
        } else {
                u32 cs_count = DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
@@ -435,14 +460,14 @@ static int check_sch_tt(struct usb_device *udev,
                 * must never schedule Start-Split in Y6
                 */
                if (start_ss == 6)
-                       return -ERANGE;
+                       return -ESCH_SS_Y6;
 
                /* one uframe for ss + one uframe for idle */
                start_cs = (start_ss + 2) % 8;
                last_cs = start_cs + cs_count - 1;
 
                if (last_cs > 7)
-                       return -ERANGE;
+                       return -ESCH_CS_OVERFLOW;
 
                if (sch_ep->ep_type == ISOC_IN_EP)
                        extra_cs_count = (last_cs == 7) ? 1 : 2;
@@ -454,7 +479,7 @@ static int check_sch_tt(struct usb_device *udev,
                        cs_count = 7; /* HW limit */
 
                if (test_bit(offset, tt->ss_bit_map))
-                       return -ERANGE;
+                       return -ESCH_SS_OVERLAP;
 
                sch_ep->cs_count = cs_count;
                /* one for ss, the other for idle */
@@ -547,7 +572,7 @@ static int check_sch_bw(struct usb_device *udev,
        u32 esit_boundary;
        u32 min_num_budget;
        u32 min_cs_count;
-       int ret;
+       int ret = 0;
 
        /*
         * Search through all possible schedule microframes.
@@ -588,7 +613,7 @@ static int check_sch_bw(struct usb_device *udev,
 
        /* check bandwidth */
        if (min_bw > bw_boundary)
-               return -ERANGE;
+               return ret ? ret : -ESCH_BW_OVERFLOW;
 
        sch_ep->offset = min_index;
        sch_ep->cs_count = min_cs_count;
@@ -765,7 +790,8 @@ int xhci_mtk_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
 
                ret = check_sch_bw(udev, sch_bw, sch_ep);
                if (ret) {
-                       xhci_err(xhci, "Not enough bandwidth!\n");
+                       xhci_err(xhci, "Not enough bandwidth! (%s)\n",
+                                sch_error_string(-ret));
                        return -ENOSPC;
                }
        }