usb: xhci-mtk: add a bandwidth budget table

In order to estimate when fs/ls transactions appear on a downstream bus,
the host must calculate a best case full-speed budget, use a table to
track how many bytes occure in each microframe.
This patch is prepared for introducing an improved bandwidth scheduling.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20230830122820.18859-1-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index 579899eb24c15245f3f70120b9f4df1e2a1de547..93d962b159b404e5e2cb3f0e2520de901f1c083b 100644 (file)
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -19,6 +19,13 @@
 #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, assume extra-cs budget is 0
+ * for fs isoc in : 1 ss + 1 idle + 6 cs (roundup(1023/188))
+ */
+#define TT_MICROFRAMES_MAX     8
+/* offset from SS for fs/ls isoc/intr ep (ss + idle) */
+#define CS_OFFSET      2
 
 #define DBG_BUF_EN     64
 
@@ -237,17 +244,26 @@ static void drop_tt(struct usb_device *udev)
 
 static struct mu3h_sch_ep_info *
 create_sch_ep(struct xhci_hcd_mtk *mtk, struct usb_device *udev,
-             struct usb_host_endpoint *ep)
+             struct usb_host_endpoint *ep, struct xhci_ep_ctx *ep_ctx)
 {
        struct mu3h_sch_ep_info *sch_ep;
        struct mu3h_sch_bw_info *bw_info;
        struct mu3h_sch_tt *tt = NULL;
+       u32 len;
 
        bw_info = get_bw_info(mtk, udev, ep);
        if (!bw_info)
                return ERR_PTR(-ENODEV);
 
-       sch_ep = kzalloc(sizeof(*sch_ep), GFP_KERNEL);
+       if (is_fs_or_ls(udev->speed))
+               len = TT_MICROFRAMES_MAX;
+       else if ((udev->speed >= USB_SPEED_SUPER) &&
+                usb_endpoint_xfer_isoc(&ep->desc))
+               len = get_esit(ep_ctx);
+       else
+               len = 1;
+
+       sch_ep = kzalloc(struct_size(sch_ep, bw_budget_table, len), GFP_KERNEL);
        if (!sch_ep)
                return ERR_PTR(-ENOMEM);
 
@@ -279,7 +295,11 @@ static void setup_sch_info(struct xhci_ep_ctx *ep_ctx,
        u32 mult;
        u32 esit_pkts;
        u32 max_esit_payload;
+       u32 bw_per_microframe;
+       u32 *bwb_table;
+       int i;
 
+       bwb_table = sch_ep->bw_budget_table;
        ep_type = CTX_TO_EP_TYPE(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));
@@ -313,7 +333,7 @@ static void setup_sch_info(struct xhci_ep_ctx *ep_ctx,
                 * opportunities per microframe
                 */
                sch_ep->pkts = max_burst + 1;
-               sch_ep->bw_cost_per_microframe = maxpkt * sch_ep->pkts;
+               bwb_table[0] = maxpkt * sch_ep->pkts;
        } else if (sch_ep->speed >= USB_SPEED_SUPER) {
                /* usb3_r1 spec section4.4.7 & 4.4.8 */
                sch_ep->cs_count = 0;
@@ -330,6 +350,7 @@ static void setup_sch_info(struct xhci_ep_ctx *ep_ctx,
                if (ep_type == INT_IN_EP || ep_type == INT_OUT_EP) {
                        sch_ep->pkts = esit_pkts;
                        sch_ep->num_budget_microframes = 1;
+                       bwb_table[0] = maxpkt * sch_ep->pkts;
                }
 
                if (ep_type == ISOC_IN_EP || ep_type == ISOC_OUT_EP) {
@@ -346,18 +367,52 @@ static void setup_sch_info(struct xhci_ep_ctx *ep_ctx,
                                DIV_ROUND_UP(esit_pkts, sch_ep->pkts);
 
                        sch_ep->repeat = !!(sch_ep->num_budget_microframes > 1);
+                       bw_per_microframe = maxpkt * sch_ep->pkts;
+
+                       for (i = 0; i < sch_ep->num_budget_microframes - 1; i++)
+                               bwb_table[i] = bw_per_microframe;
+
+                       /* last one <= bw_per_microframe */
+                       bwb_table[i] = maxpkt * esit_pkts - i * bw_per_microframe;
                }
-               sch_ep->bw_cost_per_microframe = maxpkt * sch_ep->pkts;
        } else if (is_fs_or_ls(sch_ep->speed)) {
                sch_ep->pkts = 1; /* at most one packet for each microframe */
 
                /*
-                * num_budget_microframes and cs_count will be updated when
+                * @cs_count will be updated to add extra-cs when
                 * check TT for INT_OUT_EP, ISOC/INT_IN_EP type
+                * @maxpkt <= 1023;
                 */
                sch_ep->cs_count = DIV_ROUND_UP(maxpkt, FS_PAYLOAD_MAX);
                sch_ep->num_budget_microframes = sch_ep->cs_count;
-               sch_ep->bw_cost_per_microframe = min_t(u32, maxpkt, FS_PAYLOAD_MAX);
+
+               /* init budget table */
+               if (ep_type == ISOC_OUT_EP) {
+                       for (i = 0; i < sch_ep->cs_count - 1; i++)
+                               bwb_table[i] = FS_PAYLOAD_MAX;
+
+                       bwb_table[i] = maxpkt - i * FS_PAYLOAD_MAX;
+               } else if (ep_type == INT_OUT_EP) {
+                       /* only first one used (maxpkt <= 64), others zero */
+                       bwb_table[0] = maxpkt;
+               } else { /* INT_IN_EP or ISOC_IN_EP */
+                       bwb_table[0] = 0; /* start split */
+                       bwb_table[1] = 0; /* idle */
+                       /*
+                        * @cs_count will be updated according to cs position
+                        * (add 1 or 2 extra-cs), but assume only first
+                        * @num_budget_microframes elements will be used later,
+                        * although in fact it does not (extra-cs budget many receive
+                        * some data for IN ep);
+                        * @cs_count is 1 for INT_IN_EP (maxpkt <= 64);
+                        */
+                       for (i = 0; i < sch_ep->cs_count - 1; i++)
+                               bwb_table[i + CS_OFFSET] = FS_PAYLOAD_MAX;
+
+                       bwb_table[i + CS_OFFSET] = maxpkt - i * FS_PAYLOAD_MAX;
+                       /* ss + idle */
+                       sch_ep->num_budget_microframes += CS_OFFSET;
+               }
        }
 }
 
@@ -374,7 +429,7 @@ static u32 get_max_bw(struct mu3h_sch_bw_info *sch_bw,
 
                for (j = 0; j < sch_ep->num_budget_microframes; j++) {
                        k = XHCI_MTK_BW_INDEX(base + j);
-                       bw = sch_bw->bus_bw[k] + sch_ep->bw_cost_per_microframe;
+                       bw = sch_bw->bus_bw[k] + sch_ep->bw_budget_table[j];
                        if (bw > max_bw)
                                max_bw = bw;
                }
@@ -385,16 +440,18 @@ static u32 get_max_bw(struct mu3h_sch_bw_info *sch_bw,
 static void update_bus_bw(struct mu3h_sch_bw_info *sch_bw,
        struct mu3h_sch_ep_info *sch_ep, bool used)
 {
-       int bw_updated;
        u32 base;
-       int i, j;
-
-       bw_updated = sch_ep->bw_cost_per_microframe * (used ? 1 : -1);
+       int i, j, k;
 
        for (i = 0; i < sch_ep->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[XHCI_MTK_BW_INDEX(base + j)] += bw_updated;
+               for (j = 0; j < sch_ep->num_budget_microframes; j++) {
+                       k = XHCI_MTK_BW_INDEX(base + j);
+                       if (used)
+                               sch_bw->bus_bw[k] += sch_ep->bw_budget_table[j];
+                       else
+                               sch_bw->bus_bw[k] -= sch_ep->bw_budget_table[j];
+               }
        }
 }
 
@@ -414,7 +471,7 @@ static int check_fs_bus_bw(struct mu3h_sch_ep_info *sch_ep, int offset)
                 */
                for (j = 0; j < sch_ep->num_budget_microframes; j++) {
                        k = XHCI_MTK_BW_INDEX(base + j);
-                       tmp = tt->fs_bus_bw[k] + sch_ep->bw_cost_per_microframe;
+                       tmp = tt->fs_bus_bw[k] + sch_ep->bw_budget_table[j];
                        if (tmp > FS_PAYLOAD_MAX)
                                return -ESCH_BW_OVERFLOW;
                }
@@ -454,25 +511,18 @@ static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
                        return -ESCH_SS_Y6;
 
                /* one uframe for ss + one uframe for idle */
-               start_cs = (start_ss + 2) % 8;
+               start_cs = (start_ss + CS_OFFSET) % 8;
                last_cs = start_cs + cs_count - 1;
-
                if (last_cs > 7)
                        return -ESCH_CS_OVERFLOW;
 
+               /* add extra-cs */
+               cs_count += (last_cs == 7) ? 1 : 2;
                if (cs_count > 7)
                        cs_count = 7; /* HW limit */
 
                sch_ep->cs_count = cs_count;
-               /* ss, idle are ignored */
-               sch_ep->num_budget_microframes = cs_count;
 
-               /*
-                * if interval=1, maxp >752, num_budge_micoframe is larger
-                * than sch_ep->esit, will overstep boundary
-                */
-               if (sch_ep->num_budget_microframes > sch_ep->esit)
-                       sch_ep->num_budget_microframes = sch_ep->esit;
        }
 
        return check_fs_bus_bw(sch_ep, offset);
@@ -481,17 +531,20 @@ static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
 static void update_sch_tt(struct mu3h_sch_ep_info *sch_ep, bool used)
 {
        struct mu3h_sch_tt *tt = sch_ep->sch_tt;
-       int bw_updated;
        u32 base;
-       int i, j;
+       int i, j, k;
 
-       bw_updated = sch_ep->bw_cost_per_microframe * (used ? 1 : -1);
 
        for (i = 0; i < sch_ep->num_esit; i++) {
                base = sch_ep->offset + i * sch_ep->esit;
 
-               for (j = 0; j < sch_ep->num_budget_microframes; j++)
-                       tt->fs_bus_bw[XHCI_MTK_BW_INDEX(base + j)] += bw_updated;
+               for (j = 0; j < sch_ep->num_budget_microframes; j++) {
+                       k = XHCI_MTK_BW_INDEX(base + j);
+                       if (used)
+                               tt->fs_bus_bw[k] += (u16)sch_ep->bw_budget_table[j];
+                       else
+                               tt->fs_bus_bw[k] -= (u16)sch_ep->bw_budget_table[j];
+               }
        }
 
        if (used)
@@ -651,7 +704,7 @@ static int add_ep_quirk(struct usb_hcd *hcd, struct usb_device *udev,
 
        xhci_dbg(xhci, "%s %s\n", __func__, decode_ep(ep, udev->speed));
 
-       sch_ep = create_sch_ep(mtk, udev, ep);
+       sch_ep = create_sch_ep(mtk, udev, ep, ep_ctx);
        if (IS_ERR_OR_NULL(sch_ep))
                return -ENOMEM;
 

diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h
index faaaf05e36ce0963a5108b2d0a997024464f023c..ef8af20b5e8879ef1253081b863390dae7097a15 100644 (file)
--- a/drivers/usb/host/xhci-mtk.h
+++ b/drivers/usb/host/xhci-mtk.h
@@ -58,7 +58,6 @@ struct mu3h_sch_bw_info {
  * @num_esit: number of @esit in a period
  * @num_budget_microframes: number of continuous uframes
  *             (@repeat==1) scheduled within the interval
- * @bw_cost_per_microframe: bandwidth cost per microframe
  * @hentry: hash table entry
  * @endpoint: linked into bandwidth domain which it belongs to
  * @tt_endpoint: linked into mu3h_sch_tt's list which it belongs to
@@ -83,12 +82,12 @@ 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;
        u32 num_esit;
        u32 num_budget_microframes;
-       u32 bw_cost_per_microframe;
        struct list_head endpoint;
        struct hlist_node hentry;
        struct list_head tt_endpoint;
@@ -108,6 +107,7 @@ struct mu3h_sch_ep_info {
        u32 pkts;
        u32 cs_count;
        u32 burst_mode;
+       u32 bw_budget_table[];
 };
 
 #define MU3C_U3_PORT_MAX 4