[PATCH 2/2] usb: xhci-mtk: relax periodic TT bandwidth checking
From: Ikjoon Jang
Date: Tue Mar 30 2021 - 04:07:32 EST
Software bandwidth checking logics used by xhci-mtk puts
a quite heavy constraints to TT periodic endpoint allocations.
This patch provides a relaxed bandwidth calculation by
- Allowing multiple periodic transactions in a same microframe
for a device with multiple interrupt endpoints.
- Using best case budget instead of maximum number of
complete-split when calculating byte budgets on lower speed bus
Without this patch, a typical full speed audio headset with
3 periodic endpoints (audio isoc-in/out, input int-in) cannot be
configured with xhci-mtk.
Signed-off-by: Ikjoon Jang <ikjn@xxxxxxxxxxxx>
---
drivers/usb/host/xhci-mtk-sch.c | 68 ++++++++++-----------------------
drivers/usb/host/xhci-mtk.h | 2 -
2 files changed, 20 insertions(+), 50 deletions(-)
diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index 0cb41007ec65..76827e48049a 100644
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -388,13 +388,17 @@ static void setup_sch_info(struct xhci_ep_ctx *ep_ctx,
} else { /* INT_IN_EP or ISOC_IN_EP */
bwb_table[0] = 0; /* start split */
bwb_table[1] = 0; /* idle */
+
+ sch_ep->num_budget_microframes += 2;
+ if (sch_ep->num_budget_microframes > sch_ep->esit)
+ sch_ep->num_budget_microframes = sch_ep->esit;
/*
* due to cs_count will be updated according to cs
* position, assign all remainder budget array
* elements as @bw_cost_per_microframe, but only first
* @num_budget_microframes elements will be used later
*/
- for (i = 2; i < TT_MICROFRAMES_MAX; i++)
+ for (i = 2; i < sch_ep->num_budget_microframes; i++)
bwb_table[i] = sch_ep->bw_cost_per_microframe;
}
}
@@ -449,20 +453,17 @@ static void update_bus_bw(struct mu3h_sch_bw_info *sch_bw,
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, tmp;
- int base;
int i, j;
+ const int nr_lower_uframes =
+ DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
- num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
- for (i = 0; i < num_esit; i++) {
- base = offset + i * sch_ep->esit;
-
+ for (i = offset; i < XHCI_MTK_MAX_ESIT; i += sch_ep->esit) {
/*
* Compared with hs bus, no matter what ep type,
* the hub will always delay one uframe to send data
*/
- for (j = 0; j < sch_ep->cs_count; j++) {
- tmp = tt->fs_bus_bw[base + j] + sch_ep->bw_cost_per_microframe;
+ for (j = 0; j < nr_lower_uframes; j++) {
+ u32 tmp = tt->fs_bus_bw[i + j + 1] + sch_ep->bw_cost_per_microframe;
if (tmp > FS_PAYLOAD_MAX)
return -ESCH_BW_OVERFLOW;
}
@@ -473,11 +474,9 @@ static int check_fs_bus_bw(struct mu3h_sch_ep_info *sch_ep, int offset)
static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
{
- struct mu3h_sch_tt *tt = sch_ep->sch_tt;
u32 extra_cs_count;
u32 start_ss, last_ss;
u32 start_cs, last_cs;
- int i;
if (!sch_ep->sch_tt)
return 0;
@@ -494,10 +493,6 @@ static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
if (!(start_ss == 7 || last_ss < 6))
return -ESCH_SS_Y6;
- for (i = 0; i < sch_ep->cs_count; i++)
- if (test_bit(offset + i, tt->ss_bit_map))
- return -ESCH_SS_OVERLAP;
-
} else {
u32 cs_count = DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
@@ -524,19 +519,7 @@ static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
if (cs_count > 7)
cs_count = 7; /* HW limit */
- if (test_bit(offset, tt->ss_bit_map))
- return -ESCH_SS_OVERLAP;
-
sch_ep->cs_count = cs_count;
- /* one for ss, the other for idle */
- sch_ep->num_budget_microframes = cs_count + 2;
-
- /*
- * 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);
@@ -545,31 +528,18 @@ 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;
- u32 base, num_esit;
- int bw_updated;
- int bits;
- int i, j;
-
- num_esit = XHCI_MTK_MAX_ESIT / sch_ep->esit;
- bits = (sch_ep->ep_type == ISOC_OUT_EP) ? sch_ep->cs_count : 1;
+ int i, j, bw_updated;
+ const int nr_lower_uframes =
+ DIV_ROUND_UP(sch_ep->maxpkt, FS_PAYLOAD_MAX);
if (used)
bw_updated = sch_ep->bw_cost_per_microframe;
else
bw_updated = -sch_ep->bw_cost_per_microframe;
- for (i = 0; i < num_esit; i++) {
- base = sch_ep->offset + i * sch_ep->esit;
-
- for (j = 0; j < bits; j++) {
- if (used)
- set_bit(base + j, tt->ss_bit_map);
- else
- clear_bit(base + j, tt->ss_bit_map);
- }
-
- for (j = 0; j < sch_ep->cs_count; j++)
- tt->fs_bus_bw[base + j] += bw_updated;
+ for (i = sch_ep->offset; i < XHCI_MTK_MAX_ESIT; i += sch_ep->esit) {
+ for (j = 0; j < nr_lower_uframes; j++)
+ tt->fs_bus_bw[i+ j + 1] += bw_updated;
}
if (used)
@@ -634,9 +604,11 @@ static int check_sch_bw(struct mu3h_sch_bw_info *sch_bw,
if (min_bw > worst_bw) {
min_bw = worst_bw;
found = i;
+ /* fastpath: bandwidth contributions to host is low
+ * when it's fs/ls */
+ if (sch_ep->sch_tt || min_bw == 0)
+ break;
}
- if (min_bw == 0)
- break;
}
/* check bandwidth */
diff --git a/drivers/usb/host/xhci-mtk.h b/drivers/usb/host/xhci-mtk.h
index 621ec1a85009..8a879f99ae1c 100644
--- a/drivers/usb/host/xhci-mtk.h
+++ b/drivers/usb/host/xhci-mtk.h
@@ -20,12 +20,10 @@
#define XHCI_MTK_MAX_ESIT 64
/**
- * @ss_bit_map: used to avoid start split microframes overlay
* @fs_bus_bw: array to keep track of bandwidth already used for FS
* @ep_list: Endpoints using this TT
*/
struct mu3h_sch_tt {
- DECLARE_BITMAP(ss_bit_map, XHCI_MTK_MAX_ESIT);
u32 fs_bus_bw[XHCI_MTK_MAX_ESIT];
struct list_head ep_list;
};
--
2.31.0.291.g576ba9dcdaf-goog