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Subject[RFC v4 PATCH] usb: xhci-mtk: improve bandwidth scheduling with TT
Date
When the USB headset is plug into an external hub, sometimes
can't set config due to not enough bandwidth, so need improve
LS/FS INT/ISOC bandwidth scheduling with TT.

Fixes: 08e469de87a2 ("usb: xhci-mtk: supports bandwidth scheduling with multi-TT")
Signed-off-by: Yaqii Wu <yaqii.wu@mediatek.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
---
drivers/usb/host/xhci-mtk-sch.c | 270 +++++++++++++++++++++++---------
drivers/usb/host/xhci-mtk.h | 8 +-
2 files changed, 201 insertions(+), 77 deletions(-)

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index b45e5bf08997..f3cdfcf4e5bf 100644
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -32,6 +32,35 @@
#define EP_BOFFSET(p) ((p) & 0x3fff)
#define EP_BREPEAT(p) (((p) & 0x7fff) << 16)

+enum mtk_sch_err_type {
+ SCH_SUCCESS = 0,
+ SCH_ERR_Y6,
+ SCH_SS_OVERLAP,
+ SCH_CS_OVERFLOW,
+ SCH_BW_OVERFLOW,
+ SCH_FIXME,
+};
+
+static char *sch_error_string(enum mtk_sch_err_type error)
+{
+ switch (error) {
+ case SCH_SUCCESS:
+ return "Success";
+ case SCH_ERR_Y6:
+ return "Can't schedule Start-Split in Y6";
+ case SCH_SS_OVERLAP:
+ return "Can't find a suitable Start-Split location";
+ case SCH_CS_OVERFLOW:
+ return "The last Complete-Split is greater than 7";
+ case SCH_BW_OVERFLOW:
+ return "Bandwidth exceeds the max limit";
+ case SCH_FIXME:
+ return "FIXME, to be resolved";
+ default:
+ return "Unknown error type";
+ }
+}
+
static int is_fs_or_ls(enum usb_device_speed speed)
{
return speed == USB_SPEED_FULL || speed == USB_SPEED_LOW;
@@ -81,11 +110,22 @@ static u32 get_esit(struct xhci_ep_ctx *ep_ctx)
return esit;
}

+static u32 get_bw_boundary(enum usb_device_speed speed)
+{
+ switch (speed) {
+ case USB_SPEED_SUPER_PLUS:
+ return SSP_BW_BOUNDARY;
+ case USB_SPEED_SUPER:
+ return SS_BW_BOUNDARY;
+ default:
+ return HS_BW_BOUNDARY;
+ }
+}
+
static struct mu3h_sch_tt *find_tt(struct usb_device *udev)
{
struct usb_tt *utt = udev->tt;
struct mu3h_sch_tt *tt, **tt_index, **ptt;
- unsigned int port;
bool allocated_index = false;

if (!utt)
@@ -107,10 +147,9 @@ static struct mu3h_sch_tt *find_tt(struct usb_device *udev)
utt->hcpriv = tt_index;
allocated_index = true;
}
- port = udev->ttport - 1;
- ptt = &tt_index[port];
+
+ ptt = &tt_index[udev->ttport - 1];
} else {
- port = 0;
ptt = (struct mu3h_sch_tt **) &utt->hcpriv;
}

@@ -125,8 +164,7 @@ static struct mu3h_sch_tt *find_tt(struct usb_device *udev)
return ERR_PTR(-ENOMEM);
}
INIT_LIST_HEAD(&tt->ep_list);
- tt->usb_tt = utt;
- tt->tt_port = port;
+
*ptt = tt;
}

@@ -206,6 +244,15 @@ static struct mu3h_sch_ep_info *create_sch_ep(struct usb_device *udev,
return sch_ep;
}

+static void delete_sch_ep(struct usb_device *udev, struct mu3h_sch_ep_info *sch_ep)
+{
+ if (sch_ep->sch_tt)
+ drop_tt(udev);
+
+ list_del(&sch_ep->endpoint);
+ kfree(sch_ep);
+}
+
static void setup_sch_info(struct usb_device *udev,
struct xhci_ep_ctx *ep_ctx, struct mu3h_sch_ep_info *sch_ep)
{
@@ -375,21 +422,55 @@ static void update_bus_bw(struct mu3h_sch_bw_info *sch_bw,
sch_ep->bw_budget_table[j];
}
}
- sch_ep->allocated = used;
}

-static int check_sch_tt(struct usb_device *udev,
- struct mu3h_sch_ep_info *sch_ep, u32 offset)
+static int check_fs_bus_bw(struct mu3h_sch_ep_info *sch_ep, int offset)
+{
+ struct mu3h_sch_tt *tt = sch_ep->sch_tt;
+ u32 num_esit, base;
+ u32 i, j;
+ u32 tmp;
+
+ num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
+
+ for (i = 0; i < num_esit; i++) {
+ base = offset + i * sch_ep->esit;
+
+ /*
+ * Compared with hs bus, no matter what ep type
+ * The hub will always delay one uframe to send
+ * data for us. As described in the figure below.
+ */
+ if (sch_ep->ep_type == ISOC_OUT_EP) {
+ for (j = 0; j < sch_ep->num_budget_microframes; j++) {
+ tmp = tt->fs_bus_bw[base + 1 + j]
+ + sch_ep->bw_cost_per_microframe;
+
+ if (tmp > FS_PAYLOAD_MAX)
+ return SCH_BW_OVERFLOW;
+ }
+ } else {
+ for (j = 0; j < sch_ep->cs_count; j++) {
+ tmp = tt->fs_bus_bw[base + 1 + j]
+ + sch_ep->bw_cost_per_microframe;
+
+ if (tmp > FS_PAYLOAD_MAX)
+ return SCH_BW_OVERFLOW;
+ }
+ }
+ }
+ return SCH_SUCCESS;
+}
+
+static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, int offset)
{
struct mu3h_sch_tt *tt = sch_ep->sch_tt;
u32 extra_cs_count;
- u32 fs_budget_start;
u32 start_ss, last_ss;
u32 start_cs, last_cs;
- int i;
+ u32 i;

start_ss = offset % 8;
- fs_budget_start = (start_ss + 1) % 8;

if (sch_ep->ep_type == ISOC_OUT_EP) {
last_ss = start_ss + sch_ep->cs_count - 1;
@@ -399,12 +480,12 @@ 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;
-
- for (i = 0; i < sch_ep->cs_count; i++)
- if (test_bit(offset + i, tt->split_bit_map))
- return -ERANGE;
+ return SCH_ERR_Y6;

+ for (i = 0; i < sch_ep->cs_count; i++) {
+ if (test_bit(offset + i, tt->ss_bit_map))
+ return SCH_SS_OVERLAP;
+ }
} else {
u32 cs_count = DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);

@@ -413,27 +494,36 @@ static int check_sch_tt(struct usb_device *udev,
* must never schedule Start-Split in Y6
*/
if (start_ss == 6)
- return -ERANGE;
+ return SCH_ERR_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 SCH_CS_OVERFLOW;

+ /*
+ * usb_20 spec section11.18, the bottom of page 378:
+ * For interrupt endpoints, the maximum size of the LS/FS
+ * transaction guarantees that it can never require more than
+ * two complete-split transactions.
+ */
if (sch_ep->ep_type == ISOC_IN_EP)
extra_cs_count = (last_cs == 7) ? 1 : 2;
else /* ep_type : INTR IN / INTR OUT */
- extra_cs_count = (fs_budget_start == 6) ? 1 : 2;
+ extra_cs_count = 1;

cs_count += extra_cs_count;
if (cs_count > 7)
cs_count = 7; /* HW limit */

- for (i = 0; i < cs_count + 2; i++) {
- if (test_bit(offset + i, tt->split_bit_map))
- return -ERANGE;
+ if (test_bit(offset, tt->ss_bit_map))
+ return SCH_SS_OVERLAP;
+
+ if (sch_ep->ep_type == INT_OUT_EP) {
+ if (test_bit(offset, tt->idle_bit_map))
+ return SCH_FIXME;
}

sch_ep->cs_count = cs_count;
@@ -448,41 +538,88 @@ static int check_sch_tt(struct usb_device *udev,
sch_ep->num_budget_microframes = sch_ep->esit;
}

- return 0;
+ return check_fs_bus_bw(sch_ep, offset);
}

-static void update_sch_tt(struct usb_device *udev,
- struct mu3h_sch_ep_info *sch_ep)
+static void update_sch_tt(struct mu3h_sch_ep_info *sch_ep, bool used)
{
struct mu3h_sch_tt *tt = sch_ep->sch_tt;
u32 base, num_esit;
- int i, j;
+ u32 i, j;

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++)
- set_bit(base + j, tt->split_bit_map);
+
+ if (sch_ep->ep_type == ISOC_OUT_EP) {
+ for (j = 0; j < sch_ep->num_budget_microframes; j++) {
+ if (used) {
+ set_bit(base + j, tt->ss_bit_map);
+ tt->fs_bus_bw[base + 1 + j] +=
+ sch_ep->bw_cost_per_microframe;
+ } else {
+ clear_bit(base + j, tt->ss_bit_map);
+ tt->fs_bus_bw[base + 1 + j] -=
+ sch_ep->bw_cost_per_microframe;
+ }
+ }
+ } else {
+ if (used)
+ set_bit(base, tt->ss_bit_map);
+ else
+ clear_bit(base, tt->ss_bit_map);
+
+ if (sch_ep->ep_type == INT_OUT_EP) {
+ if (used)
+ set_bit(base + 1, tt->idle_bit_map);
+ else
+ clear_bit(base + 1, tt->idle_bit_map);
+ }
+
+ for (j = 0; j < sch_ep->cs_count; j++) {
+ if (used)
+ tt->fs_bus_bw[base + 1 + j] +=
+ sch_ep->bw_cost_per_microframe;
+ else
+ tt->fs_bus_bw[base + 1 + j] -=
+ sch_ep->bw_cost_per_microframe;
+ }
+ }
+ }
+}
+
+static int load_ep_bw(struct mu3h_sch_bw_info *sch_bw,
+ struct mu3h_sch_ep_info *sch_ep, bool loaded)
+{
+ struct mu3h_sch_tt *tt = sch_ep->sch_tt;
+
+ if (sch_ep->sch_tt) {
+ update_sch_tt(sch_ep, loaded);
+ if (loaded)
+ list_add_tail(&sch_ep->tt_endpoint, &tt->ep_list);
+ else
+ list_del(&sch_ep->tt_endpoint);
}

- list_add_tail(&sch_ep->tt_endpoint, &tt->ep_list);
+ /* update bus bandwidth info */
+ update_bus_bw(sch_bw, sch_ep, loaded);
+ sch_ep->allocated = loaded;
+ return 0;
}

static int check_sch_bw(struct usb_device *udev,
struct mu3h_sch_bw_info *sch_bw, struct mu3h_sch_ep_info *sch_ep)
{
u32 offset;
- u32 esit;
u32 min_bw;
u32 min_index;
u32 worst_bw;
u32 bw_boundary;
+ u32 boundary;
u32 min_num_budget;
u32 min_cs_count;
- bool tt_offset_ok = false;
- int ret;
-
- esit = sch_ep->esit;
+ int ret = 0;

/*
* Search through all possible schedule microframes.
@@ -492,16 +629,20 @@ static int check_sch_bw(struct usb_device *udev,
min_index = 0;
min_cs_count = sch_ep->cs_count;
min_num_budget = sch_ep->num_budget_microframes;
- for (offset = 0; offset < esit; offset++) {
- if (is_fs_or_ls(udev->speed)) {
- ret = check_sch_tt(udev, sch_ep, offset);
- if (ret)
+
+ if (is_fs_or_ls(udev->speed) && sch_ep->ep_type != ISOC_OUT_EP)
+ boundary = sch_ep->esit + 1;
+ else
+ boundary = sch_ep->esit;
+
+ for (offset = 0; offset < sch_ep->esit; offset++) {
+ if (sch_ep->sch_tt) {
+ ret = check_sch_tt(sch_ep, offset);
+ if (ret != SCH_SUCCESS)
continue;
- else
- tt_offset_ok = true;
}

- if ((offset + sch_ep->num_budget_microframes) > sch_ep->esit)
+ if ((offset + sch_ep->num_budget_microframes) > boundary)
break;

worst_bw = get_max_bw(sch_bw, sch_ep, offset);
@@ -515,33 +656,22 @@ static int check_sch_bw(struct usb_device *udev,
break;
}

- if (udev->speed == USB_SPEED_SUPER_PLUS)
- bw_boundary = SSP_BW_BOUNDARY;
- else if (udev->speed == USB_SPEED_SUPER)
- bw_boundary = SS_BW_BOUNDARY;
- else
- bw_boundary = HS_BW_BOUNDARY;
-
+ bw_boundary = get_bw_boundary(udev->speed);
/* check bandwidth */
- if (min_bw > bw_boundary)
+ if (min_bw > bw_boundary) {
+ if (ret) {
+ dev_err(&udev->dev, "%s %s\n", __func__,
+ sch_error_string(ret));
+ return -ret;
+ }
+
return -ERANGE;
+ }

sch_ep->offset = min_index;
sch_ep->cs_count = min_cs_count;
sch_ep->num_budget_microframes = min_num_budget;
-
- if (is_fs_or_ls(udev->speed)) {
- /* all offset for tt is not ok*/
- if (!tt_offset_ok)
- return -ERANGE;
-
- update_sch_tt(udev, sch_ep);
- }
-
- /* update bus bandwidth info */
- update_bus_bw(sch_bw, sch_ep, 1);
-
- return 0;
+ return load_ep_bw(sch_bw, sch_ep, true);
}

static void destroy_sch_ep(struct usb_device *udev,
@@ -549,23 +679,17 @@ static void destroy_sch_ep(struct usb_device *udev,
{
/* only release ep bw check passed by check_sch_bw() */
if (sch_ep->allocated)
- update_bus_bw(sch_bw, sch_ep, 0);
+ load_ep_bw(sch_bw, sch_ep, false);

- list_del(&sch_ep->endpoint);
-
- if (sch_ep->sch_tt) {
- list_del(&sch_ep->tt_endpoint);
- drop_tt(udev);
- }
- kfree(sch_ep);
+ delete_sch_ep(udev, sch_ep);
}

static bool need_bw_sch(struct usb_host_endpoint *ep,
enum usb_device_speed speed, int has_tt)
{
/* only for periodic endpoints */
- if (usb_endpoint_xfer_control(&ep->desc)
- || usb_endpoint_xfer_bulk(&ep->desc))
+ if (usb_endpoint_xfer_control(&ep->desc) ||
+ usb_endpoint_xfer_bulk(&ep->desc))
return false;

/*
diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h
index cbb09dfea62e..81e9b56958c5 100644
--- a/drivers/usb/host/xhci-mtk.h
+++ b/drivers/usb/host/xhci-mtk.h
@@ -26,10 +26,10 @@
* @tt_port: TT port number
*/
struct mu3h_sch_tt {
- DECLARE_BITMAP(split_bit_map, XHCI_MTK_MAX_ESIT);
+ DECLARE_BITMAP(ss_bit_map, XHCI_MTK_MAX_ESIT);
+ DECLARE_BITMAP(idle_bit_map, XHCI_MTK_MAX_ESIT);
+ u32 fs_bus_bw[XHCI_MTK_MAX_ESIT + 1];
struct list_head ep_list;
- struct usb_tt *usb_tt;
- int tt_port;
};

/**
@@ -84,9 +84,9 @@ struct mu3h_sch_ep_info {
struct list_head endpoint;
struct list_head tt_endpoint;
struct mu3h_sch_tt *sch_tt;
+ struct usb_host_endpoint *ep;
u32 ep_type;
u32 maxpkt;
- void *ep;
bool allocated;
/*
* mtk xHCI scheduling information put into reserved DWs
--
2.18.0
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