Changeset 94e9c29 in mainline for uspace/drv/bus/usb/xhci/isoch.c

Timestamp:

2018-01-13T00:54:24Z (6 years ago)

Author:

Salmelu <salmelu@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

230ef1c

Parents:

0e7380f

Message:

xhci: Isoch mfindex epoch counting

Isochronous mfindex is now saved together with wrap epochs.
This allows us to work with endpoints with larger intervals,
that need to schedule over epochs.

File:

• uspace/drv/bus/usb/xhci/isoch.c (modified) (11 diffs)

uspace/drv/bus/usb/xhci/isoch.c

@@ -80 +80 @@
 
         fibril_timer_clear_locked(isoch->feeding_timer);
-        isoch->last_mfindex = -1U;
+        isoch->last_mf = -1U;
         usb_log_info("[isoch] Endpoint" XHCI_EP_FMT ": Data flow reset.", XHCI_EP_ARGS(*ep));
 }
@@ -195 +195 @@
 }
 
+/** The number of bits the MFINDEX is stored in at HW */
+#define EPOCH_BITS 14
+/** The delay in usec for the epoch wrap */
+#define EPOCH_DELAY 500000
+/** The amount of microframes the epoch is checked for a delay */
+#define EPOCH_LOW_MFINDEX 8 * 100
+
+static inline uint64_t get_system_time()
+{
+        struct timeval tv;
+        getuptime(&tv);
+        return ((uint64_t) tv.tv_sec) * 1000000 + ((uint64_t) tv.tv_usec);
+}
+
+static inline uint64_t get_current_microframe(const xhci_hc_t *hc)
+{
+        const uint32_t reg_mfindex = XHCI_REG_RD(hc->rt_regs, XHCI_RT_MFINDEX);
+        /*
+         * If the mfindex is low and the time passed since last mfindex wrap
+         * is too high, we have entered the new epoch already (and haven't received event yet).
+         */
+        uint64_t epoch = hc->wrap_count;
+        if (reg_mfindex < EPOCH_LOW_MFINDEX && get_system_time() - hc->wrap_time > EPOCH_DELAY) {
+                ++epoch;
+        }
+        return (epoch << EPOCH_BITS) + reg_mfindex;
+}
+
 static inline void calc_next_mfindex(xhci_endpoint_t *ep, xhci_isoch_transfer_t *it)
 {
         xhci_isoch_t * const isoch = ep->isoch;
-        if (isoch->last_mfindex == -1U) {
+        if (isoch->last_mf == -1U) {
                 const xhci_bus_t *bus = bus_to_xhci_bus(ep->base.device->bus);
                 const xhci_hc_t *hc = bus->hc;
 
-                /* Choose some number, give us a little time to prepare the
-                 * buffers */
-                it->mfindex = XHCI_REG_RD(hc->rt_regs, XHCI_RT_MFINDEX) + 1
-                       + isoch->buffer_count * ep->interval
-                       + hc->ist;
+                /* Delay the first frame by some time to fill the buffer, but at most 10 miliseconds. */
+                const uint64_t delay = min(isoch->buffer_count * ep->interval, 10 * 8);
+                it->mfindex = get_current_microframe(hc) + 1 + delay + hc->ist;
 
                 // Align to ESIT start boundary
@@ -212 +238 @@
                 it->mfindex &= ~(ep->interval - 1);
         } else {
-                it->mfindex = (isoch->last_mfindex + ep->interval) % XHCI_MFINDEX_MAX;
+                it->mfindex = isoch->last_mf + ep->interval;
         }
 }
@@ -227 +253 @@
 typedef struct {
         window_position_t position;
-        uint32_t offset;
+        uint64_t offset;
 } window_decision_t;
 
@@ -236 +262 @@
  * uframes it's off.
  */
-static inline void window_decide(window_decision_t *res, xhci_hc_t *hc, uint32_t mfindex)
-{
-        uint32_t current_mfindex = XHCI_REG_RD(hc->rt_regs, XHCI_RT_MFINDEX) + 1;
-
-        /*
-         * In your mind, rotate the clock so the window is at its beginning.
-         * The length of the window is always the same, and by rotating the
-         * mfindex too, we can decide by the value of it easily.
-         */
-        mfindex = (mfindex - current_mfindex - hc->ist + XHCI_MFINDEX_MAX) % XHCI_MFINDEX_MAX;
-        const uint32_t end = END_FRAME_DELAY - hc->ist;
-        const uint32_t threshold = (XHCI_MFINDEX_MAX + end) / 2;
-
-        if (mfindex <= end) {
+static inline void window_decide(window_decision_t *res, xhci_hc_t *hc, uint64_t mfindex)
+{
+        const uint64_t current_mf = get_current_microframe(hc);
+        const uint64_t start = current_mf + hc->ist + 1;
+        const uint64_t end = current_mf + END_FRAME_DELAY;
+
+        if (mfindex < start) {
+                res->position = WINDOW_TOO_LATE;
+                res->offset = start - mfindex;
+        } else if (mfindex <= end) {
                 res->position = WINDOW_INSIDE;
-        } else if (mfindex > threshold) {
-                res->position = WINDOW_TOO_LATE;
-                res->offset = XHCI_MFINDEX_MAX - mfindex;
         } else {
                 res->position = WINDOW_TOO_SOON;
                 res->offset = mfindex - end;
         }
-        /*
-         * TODO: The "size" of the clock is too low. We have to scale it a bit
-         * to ensure correct scheduling of transfers, that are
-         * buffer_count * interval away from now.
-         * Maximum interval is 8 seconds, which means we need a size of
-         * 16 seconds. The size of MFIINDEX is 2 seconds only.
-         *
-         * A plan is to create a thin abstraction at HC, which would return
-         * a time from 32-bit clock, having its high bits updated by the
-         * MFINDEX Wrap Event, and low bits from the MFINDEX register. Using
-         * this 32-bit clock, one can plan 6 days ahead.
-         */
 }
 
@@ -293 +300 @@
         bool fed = false;
 
-        /*
-         * There might be a case, where no transfer can't be put on the ring immediately
-         * (for endpoints with interval >= 500ms). In that case, the transfer buffers could fill
-         * and the first condition wouldn't be enough to enter the loop.
-         */
-        while (isoch->hw_enqueue != isoch->enqueue || isoch->transfers[isoch->hw_enqueue].state == ISOCH_FILLED) {
+        while (isoch->transfers[isoch->hw_enqueue].state == ISOCH_FILLED) {
                 xhci_isoch_transfer_t * const it = &isoch->transfers[isoch->hw_enqueue];
 
@@ -317 +319 @@
 
                 case WINDOW_INSIDE:
-                        usb_log_debug2("[isoch] feeding buffer %lu at 0x%x",
+                        usb_log_debug2("[isoch] feeding buffer %lu at 0x%llx",
                             it - isoch->transfers, it->mfindex);
                         it->error = schedule_isochronous_trb(ep, it);
@@ -332 +334 @@
                 case WINDOW_TOO_LATE:
                         /* Missed the opportunity to schedule. Just mark this transfer as skipped. */
-                        usb_log_debug2("[isoch] missed feeding buffer %lu at 0x%x by %u uframes",
+                        usb_log_debug2("[isoch] missed feeding buffer %lu at 0x%llx by %llu uframes",
                             it - isoch->transfers, it->mfindex, wd.offset);
                         it->state = ISOCH_COMPLETE;
@@ -405 +407 @@
 
                 case WINDOW_TOO_LATE:
-                        usb_log_debug2("[isoch] missed feeding buffer %lu at 0x%x by %u uframes",
+                        usb_log_debug2("[isoch] missed feeding buffer %lu at 0x%llx by %llu uframes",
                             it - isoch->transfers, it->mfindex, wd.offset);
                         /* Missed the opportunity to schedule. Schedule ASAP. */
@@ -416 +418 @@
                 case WINDOW_INSIDE:
                         isoch->enqueue = (isoch->enqueue + 1) % isoch->buffer_count;
-                        isoch->last_mfindex = it->mfindex;
-
-                        usb_log_debug2("[isoch] feeding buffer %lu at 0x%x",
+                        isoch->last_mf = it->mfindex;
+
+                        usb_log_debug2("[isoch] feeding buffer %lu at 0x%llx",
                             it - isoch->transfers, it->mfindex);
 
@@ -503 +505 @@
         /* Calculate when to schedule next transfer */
         calc_next_mfindex(ep, it);
-        isoch->last_mfindex = it->mfindex;
-        usb_log_debug2("[isoch] buffer %zu will be on schedule at 0x%x", it - isoch->transfers, it->mfindex);
+        isoch->last_mf = it->mfindex;
+        usb_log_debug2("[isoch] buffer %zu will be on schedule at 0x%llx", it - isoch->transfers, it->mfindex);
 
         /* Prepare the transfer. */