Nico Huber (nico.huber@secunet.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/1123
-gerrit
commit 31887a042a68fb05a6718183aaa1eded4ea3e4a1 Author: Nico Huber nico.huber@secunet.com Date: Thu Jun 14 13:08:36 2012 +0200
libpayload: Add interrupt-queue underrun recovery to EHCI
If the queue of an interrupt transfer runs out, we have to reset the queue head. This also introduces the use of a spare transfer descriptor (TD) in interrupt queues, which assures, that a processed TD won't be reused until the host controller has written it back from his overlay.
Change-Id: Id0eeb2808b77f1c187f164eb34bd66f8f399938b Signed-off-by: Nico Huber nico.huber@secunet.com --- payloads/libpayload/drivers/usb/ehci.c | 41 ++++++++++++++++++++----------- 1 files changed, 26 insertions(+), 15 deletions(-)
diff --git a/payloads/libpayload/drivers/usb/ehci.c b/payloads/libpayload/drivers/usb/ehci.c index 9e17571..d99901a 100644 --- a/payloads/libpayload/drivers/usb/ehci.c +++ b/payloads/libpayload/drivers/usb/ehci.c @@ -410,6 +410,7 @@ typedef struct { volatile ehci_qh_t qh; intr_qtd_t *head; intr_qtd_t *tail; + intr_qtd_t *spare; u8 *data; endpoint_t *endp; int reqsize; @@ -466,7 +467,11 @@ static void *ehci_create_intr_queue(
intr_queue_t *const intrq = (intr_queue_t *)memalign(32, sizeof(intr_queue_t)); - u8 *data = (u8 *)malloc(reqsize * reqcount); + /* + * reqcount data chunks + * plus one more spare, which we'll leave out of queue + */ + u8 *data = (u8 *)malloc(reqsize * (reqcount + 1)); if (!intrq || !data) fatal("Not enough memory to create USB interrupt queue.\n"); intrq->data = data; @@ -490,6 +495,10 @@ static void *ehci_create_intr_queue( } intrq->tail = cur_td;
+ /* create spare qTD */ + intrq->spare = (intr_qtd_t *)memalign(32, sizeof(intr_qtd_t)); + fill_intr_queue_td(intrq, intrq->spare, data); + /* initialize QH */ const int endp = ep->endpoint & 0xf; memset(&intrq->qh, 0, sizeof(intrq->qh)); @@ -558,6 +567,7 @@ static void ehci_destroy_intr_queue(endpoint_t *const ep, void *const queue) /* free current interrupt qTD */ free(to_free); } + free(intrq->spare); free(intrq->data); free(intrq); } @@ -569,9 +579,7 @@ static u8 *ehci_poll_intr_queue(void *const queue) u8 *ret = NULL;
/* process if head qTD is inactive AND QH has been moved forward */ - if (!(intrq->head->td.token & QTD_ACTIVE) && - (intrq->qh.current_td_ptr != - virt_to_phys(&intrq->head->td))) { + if (!(intrq->head->td.token & QTD_ACTIVE)) { if (!(intrq->head->td.token & QTD_STATUS_MASK)) ret = intrq->head->data; else @@ -579,18 +587,21 @@ static u8 *ehci_poll_intr_queue(void *const queue) "status == 0x%02x\n", intrq->head->td.token & QTD_STATUS_MASK);
- /* save and advance our head ptr */ - intr_qtd_t *const new_td = intrq->head; - intrq->head = intrq->head->next; - - /* reuse executed qTD */ - fill_intr_queue_td(intrq, new_td, new_td->data); - - /* at last insert reused qTD at the - * end and advance our tail ptr */ - intrq->tail->td.next_qtd = virt_to_phys(&new_td->td); - intrq->tail->next = new_td; + /* insert spare qTD at the end and advance our tail ptr */ + fill_intr_queue_td(intrq, intrq->spare, intrq->spare->data); + intrq->tail->td.next_qtd = virt_to_phys(&intrq->spare->td); + intrq->tail->next = intrq->spare; intrq->tail = intrq->tail->next; + + /* reuse executed qTD as spare one and advance our head ptr */ + intrq->spare = intrq->head; + intrq->head = intrq->head->next; + } + /* reset queue if we fully processed it after underrun */ + else if (intrq->qh.td.next_qtd & QTD_TERMINATE) { + debug("resetting underrun ehci interrupt queue.\n"); + memset(&intrq->qh.td, 0, sizeof(intrq->qh.td)); + intrq->qh.td.next_qtd = virt_to_phys(&intrq->head->td); } return ret; }