[PATCH 4/6] usb: xhci-mtk: improve bandwidth scheduling

Chunfeng Yun
2018-08-29T02:55:16Z

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>
---
drivers/usb/host/xhci-mtk-sch.c | 162 +++++++++++++++++++++++++---------------
drivers/usb/host/xhci-mtk.h | 2 +
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 057f453..7efd890 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 cc59d80..f8864fc 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
--
1.9.1