usb: xhci-mtk: improve bandwidth scheduling

Mainly improve SuperSpeed ISOC bandwidth in last microframe,
and LowSpeed/FullSpeed IN INT/ISOC bandwidth in split and
idle microframes by introduing a bandwidth budget table;

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 104 insertions, 60 deletions

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index 057f453e06c5..7efd8901b2db 100644
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -18,6 +18,11 @@
 #define HS_BW_BOUNDARY  6144
 /* usb2 spec section11.18.1: at most 188 FS bytes per microframe */
 #define FS_PAYLOAD_MAX 188
+/*
+ * max number of microframes for split transfer,
+ * for fs isoc in : 1 ss + 1 idle + 7 cs
+ */
+#define TT_MICROFRAMES_MAX 9
 
 /* mtk scheduler bitmasks */
 #define EP_BPKTS(p)     ((p) & 0x3f)
@@ -64,20 +69,57 @@ static int get_bw_index(struct xhci_hcd *xhci, struct usb_device *udev,
         return bw_index;
 }
 
+static u32 get_esit(struct xhci_ep_ctx *ep_ctx)
+{
+        u32 esit;
+
+        esit = 1 << CTX_TO_EP_INTERVAL(le32_to_cpu(ep_ctx->ep_info));
+        if (esit > XHCI_MTK_MAX_ESIT)
+                esit = XHCI_MTK_MAX_ESIT;
+
+        return esit;
+}
+
+static struct mu3h_sch_ep_info *create_sch_ep(struct usb_device *udev,
+        struct usb_host_endpoint *ep, struct xhci_ep_ctx *ep_ctx)
+{
+        struct mu3h_sch_ep_info *sch_ep;
+        u32 len_bw_budget_table;
+        size_t mem_size;
+
+        if (is_fs_or_ls(udev->speed))
+                len_bw_budget_table = TT_MICROFRAMES_MAX;
+        else if ((udev->speed == USB_SPEED_SUPER)
+                        && usb_endpoint_xfer_isoc(&ep->desc))
+                len_bw_budget_table = get_esit(ep_ctx);
+        else
+                len_bw_budget_table = 1;
+
+        mem_size = sizeof(struct mu3h_sch_ep_info) +
+                        len_bw_budget_table * sizeof(u32);
+        sch_ep = kzalloc(mem_size, GFP_KERNEL);
+        if (!sch_ep)
+                return ERR_PTR(-ENOMEM);
+
+        sch_ep->ep = ep;
+
+        return sch_ep;
+}
+
 static void setup_sch_info(struct usb_device *udev,
                 struct xhci_ep_ctx *ep_ctx, struct mu3h_sch_ep_info *sch_ep)
 {
         u32 ep_type;
-        u32 ep_interval;
-        u32 max_packet_size;
+        u32 maxpkt;
         u32 max_burst;
         u32 mult;
         u32 esit_pkts;
         u32 max_esit_payload;
+        u32 *bwb_table = sch_ep->bw_budget_table;
+        int i;
 
         ep_type = CTX_TO_EP_TYPE(le32_to_cpu(ep_ctx->ep_info2));
-        ep_interval = CTX_TO_EP_INTERVAL(le32_to_cpu(ep_ctx->ep_info));
-        max_packet_size = MAX_PACKET_DECODED(le32_to_cpu(ep_ctx->ep_info2));
+        maxpkt = MAX_PACKET_DECODED(le32_to_cpu(ep_ctx->ep_info2));
         max_burst = CTX_TO_MAX_BURST(le32_to_cpu(ep_ctx->ep_info2));
         mult = CTX_TO_EP_MULT(le32_to_cpu(ep_ctx->ep_info));
         max_esit_payload =
@@ -85,9 +127,10 @@ static void setup_sch_info(struct usb_device *udev,
                         le32_to_cpu(ep_ctx->ep_info)) << 16) |
                  CTX_TO_MAX_ESIT_PAYLOAD(le32_to_cpu(ep_ctx->tx_info));
 
-        sch_ep->esit = 1 << ep_interval;
+        sch_ep->esit = get_esit(ep_ctx);
         sch_ep->offset = 0;
         sch_ep->burst_mode = 0;
+        sch_ep->repeat = 0;
 
         if (udev->speed == USB_SPEED_HIGH) {
                 sch_ep->cs_count = 0;
@@ -98,7 +141,6 @@ static void setup_sch_info(struct usb_device *udev,
                  * in a interval
                  */
                 sch_ep->num_budget_microframes = 1;
-                sch_ep->repeat = 0;
 
                 /*
                  * xHCI spec section6.2.3.4
@@ -106,26 +148,30 @@ static void setup_sch_info(struct usb_device *udev,
                  * opportunities per microframe
                  */
                 sch_ep->pkts = max_burst + 1;
-                sch_ep->bw_cost_per_microframe = max_packet_size * sch_ep->pkts;
+                sch_ep->bw_cost_per_microframe = maxpkt * sch_ep->pkts;
+                bwb_table[0] = sch_ep->bw_cost_per_microframe;
         } else if (udev->speed == USB_SPEED_SUPER) {
                 /* usb3_r1 spec section4.4.7 & 4.4.8 */
                 sch_ep->cs_count = 0;
+                sch_ep->burst_mode = 1;
                 /*
                  * some device's (d)wBytesPerInterval is set as 0,
                  * then max_esit_payload is 0, so evaluate esit_pkts from
                  * mult and burst
                  */
-                esit_pkts = DIV_ROUND_UP(max_esit_payload, max_packet_size);
+                esit_pkts = DIV_ROUND_UP(max_esit_payload, maxpkt);
                 if (esit_pkts == 0)
                         esit_pkts = (mult + 1) * (max_burst + 1);
 
                 if (ep_type == INT_IN_EP || ep_type == INT_OUT_EP) {
                         sch_ep->pkts = esit_pkts;
                         sch_ep->num_budget_microframes = 1;
-                        sch_ep->repeat = 0;
+                        bwb_table[0] = maxpkt * sch_ep->pkts;
                 }
 
                 if (ep_type == ISOC_IN_EP || ep_type == ISOC_OUT_EP) {
+                        u32 remainder;
+
                         if (sch_ep->esit == 1)
                                 sch_ep->pkts = esit_pkts;
                         else if (esit_pkts <= sch_ep->esit)
@@ -137,43 +183,37 @@ static void setup_sch_info(struct usb_device *udev,
                         sch_ep->num_budget_microframes =
                                 DIV_ROUND_UP(esit_pkts, sch_ep->pkts);
 
-                        if (sch_ep->num_budget_microframes > 1)
-                                sch_ep->repeat = 1;
-                        else
-                                sch_ep->repeat = 0;
+                        sch_ep->repeat = !!(sch_ep->num_budget_microframes > 1);
+                        sch_ep->bw_cost_per_microframe = maxpkt * sch_ep->pkts;
+
+                        remainder = sch_ep->bw_cost_per_microframe;
+                        remainder *= sch_ep->num_budget_microframes;
+                        remainder -= (maxpkt * esit_pkts);
+                        for (i = 0; i < sch_ep->num_budget_microframes - 1; i++)
+                                bwb_table[i] = sch_ep->bw_cost_per_microframe;
+
+                        /* last one <= bw_cost_per_microframe */
+                        bwb_table[i] = remainder;
                 }
-                sch_ep->bw_cost_per_microframe = max_packet_size * sch_ep->pkts;
         } else if (is_fs_or_ls(udev->speed)) {
-
-                /*
-                 * usb_20 spec section11.18.4
-                 * assume worst cases
-                 */
-                sch_ep->repeat = 0;
                 sch_ep->pkts = 1; /* at most one packet for each microframe */
-                if (ep_type == INT_IN_EP || ep_type == INT_OUT_EP) {
-                        sch_ep->cs_count = 3; /* at most need 3 CS*/
-                        /* one for SS and one for budgeted transaction */
-                        sch_ep->num_budget_microframes = sch_ep->cs_count + 2;
-                        sch_ep->bw_cost_per_microframe = max_packet_size;
-                }
-                if (ep_type == ISOC_OUT_EP) {
+                sch_ep->cs_count = DIV_ROUND_UP(maxpkt, FS_PAYLOAD_MAX);
+                sch_ep->num_budget_microframes = sch_ep->cs_count + 2;
+                sch_ep->bw_cost_per_microframe =
+                        (maxpkt < FS_PAYLOAD_MAX) ? maxpkt : FS_PAYLOAD_MAX;
 
-                        /*
-                         * the best case FS budget assumes that 188 FS bytes
-                         * occur in each microframe
-                         */
-                        sch_ep->num_budget_microframes = DIV_ROUND_UP(
-                                max_packet_size, FS_PAYLOAD_MAX);
-                        sch_ep->bw_cost_per_microframe = FS_PAYLOAD_MAX;
-                        sch_ep->cs_count = sch_ep->num_budget_microframes;
-                }
-                if (ep_type == ISOC_IN_EP) {
-                        /* at most need additional two CS. */
-                        sch_ep->cs_count = DIV_ROUND_UP(
-                                max_packet_size, FS_PAYLOAD_MAX) + 2;
-                        sch_ep->num_budget_microframes = sch_ep->cs_count + 2;
-                        sch_ep->bw_cost_per_microframe = FS_PAYLOAD_MAX;
+                /* init budget table */
+                if (ep_type == ISOC_OUT_EP) {
+                        for (i = 0; i < sch_ep->num_budget_microframes; i++)
+                                bwb_table[i] =  sch_ep->bw_cost_per_microframe;
+                } else if (ep_type == INT_OUT_EP) {
+                        /* only first one consumes bandwidth, others as zero */
+                        bwb_table[0] = sch_ep->bw_cost_per_microframe;
+                } else { /* INT_IN_EP or ISOC_IN_EP */
+                        bwb_table[0] = 0; /* start split */
+                        bwb_table[1] = 0; /* idle */
+                        for (i = 2; i < sch_ep->num_budget_microframes; i++)
+                                bwb_table[i] =  sch_ep->bw_cost_per_microframe;
                 }
         }
 }
@@ -184,6 +224,7 @@ static u32 get_max_bw(struct mu3h_sch_bw_info *sch_bw,
 {
         u32 num_esit;
         u32 max_bw = 0;
+        u32 bw;
         int i;
         int j;
 
@@ -192,15 +233,17 @@ static u32 get_max_bw(struct mu3h_sch_bw_info *sch_bw,
                 u32 base = offset + i * sch_ep->esit;
 
                 for (j = 0; j < sch_ep->num_budget_microframes; j++) {
-                        if (sch_bw->bus_bw[base + j] > max_bw)
-                                max_bw = sch_bw->bus_bw[base + j];
+                        bw = sch_bw->bus_bw[base + j] +
+                                        sch_ep->bw_budget_table[j];
+                        if (bw > max_bw)
+                                max_bw = bw;
                 }
         }
         return max_bw;
 }
 
 static void update_bus_bw(struct mu3h_sch_bw_info *sch_bw,
-        struct mu3h_sch_ep_info *sch_ep, int bw_cost)
+        struct mu3h_sch_ep_info *sch_ep, bool used)
 {
         u32 num_esit;
         u32 base;
@@ -210,8 +253,14 @@ static void update_bus_bw(struct mu3h_sch_bw_info *sch_bw,
         num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
         for (i = 0; i < num_esit; i++) {
                 base = sch_ep->offset + i * sch_ep->esit;
-                for (j = 0; j < sch_ep->num_budget_microframes; j++)
-                        sch_bw->bus_bw[base + j] += bw_cost;
+                for (j = 0; j < sch_ep->num_budget_microframes; j++) {
+                        if (used)
+                                sch_bw->bus_bw[base + j] +=
+                                        sch_ep->bw_budget_table[j];
+                        else
+                                sch_bw->bus_bw[base + j] -=
+                                        sch_ep->bw_budget_table[j];
+                }
         }
 }
 
@@ -220,17 +269,12 @@ static int check_sch_bw(struct usb_device *udev,
 {
         u32 offset;
         u32 esit;
-        u32 num_budget_microframes;
         u32 min_bw;
         u32 min_index;
         u32 worst_bw;
         u32 bw_boundary;
 
-        if (sch_ep->esit > XHCI_MTK_MAX_ESIT)
-                sch_ep->esit = XHCI_MTK_MAX_ESIT;
-
         esit = sch_ep->esit;
-        num_budget_microframes = sch_ep->num_budget_microframes;
 
         /*
          * Search through all possible schedule microframes.
@@ -239,7 +283,7 @@ static int check_sch_bw(struct usb_device *udev,
         min_bw = ~0;
         min_index = 0;
         for (offset = 0; offset < esit; offset++) {
-                if ((offset + num_budget_microframes) > sch_ep->esit)
+                if ((offset + sch_ep->num_budget_microframes) > sch_ep->esit)
                         break;
 
                 /*
@@ -263,11 +307,11 @@ static int check_sch_bw(struct usb_device *udev,
                                 ? SS_BW_BOUNDARY : HS_BW_BOUNDARY;
 
         /* check bandwidth */
-        if (min_bw + sch_ep->bw_cost_per_microframe > bw_boundary)
+        if (min_bw > bw_boundary)
                 return -ERANGE;
 
         /* update bus bandwidth info */
-        update_bus_bw(sch_bw, sch_ep, sch_ep->bw_cost_per_microframe);
+        update_bus_bw(sch_bw, sch_ep, 1);
 
         return 0;
 }
@@ -362,8 +406,8 @@ int xhci_mtk_add_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
         bw_index = get_bw_index(xhci, udev, ep);
         sch_bw = &sch_array[bw_index];
 
-        sch_ep = kzalloc(sizeof(struct mu3h_sch_ep_info), GFP_NOIO);
-        if (!sch_ep)
+        sch_ep = create_sch_ep(udev, ep, ep_ctx);
+        if (IS_ERR_OR_NULL(sch_ep))
                 return -ENOMEM;
 
         setup_sch_info(udev, ep_ctx, sch_ep);
@@ -376,7 +420,6 @@ int xhci_mtk_add_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
         }
 
         list_add_tail(&sch_ep->endpoint, &sch_bw->bw_ep_list);
-        sch_ep->ep = ep;
 
         ep_ctx->reserved[0] |= cpu_to_le32(EP_BPKTS(sch_ep->pkts)
                 | EP_BCSCOUNT(sch_ep->cs_count) | EP_BBM(sch_ep->burst_mode));
@@ -421,8 +464,7 @@ void xhci_mtk_drop_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
 
         list_for_each_entry(sch_ep, &sch_bw->bw_ep_list, endpoint) {
                 if (sch_ep->ep == ep) {
-                        update_bus_bw(sch_bw, sch_ep,
-                                -sch_ep->bw_cost_per_microframe);
+                        update_bus_bw(sch_bw, sch_ep, 0);
                         list_del(&sch_ep->endpoint);
                         kfree(sch_ep);
                         break;
diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h
index cc59d80b663b..f8864fcbd461 100644
--- a/drivers/usb/host/xhci-mtk.h
+++ b/drivers/usb/host/xhci-mtk.h
@@ -57,6 +57,7 @@ struct mu3h_sch_bw_info {
  *              times; 1: distribute the (bMaxBurst+1)*(Mult+1) packets
  *              according to @pkts and @repeat. normal mode is used by
  *              default
+ * @bw_budget_table: table to record bandwidth budget per microframe
  */
 struct mu3h_sch_ep_info {
         u32 esit;
@@ -73,6 +74,7 @@ struct mu3h_sch_ep_info {
         u32 pkts;
         u32 cs_count;
         u32 burst_mode;
+        u32 bw_budget_table[0];
 };
 
 #define MU3C_U3_PORT_MAX 4