int length, struct devrequest *req)
{
ALLOC_ALIGN_BUFFER(struct QH, qh, 1, USB_DMA_MINALIGN);
-#define QTD_COUNT 3
- ALLOC_ALIGN_BUFFER(struct qTD, qtd, QTD_COUNT, USB_DMA_MINALIGN);
+ struct qTD *qtd;
+ int qtd_count = 0;
int qtd_counter = 0;
volatile struct qTD *vtd;
le16_to_cpu(req->value), le16_to_cpu(req->value),
le16_to_cpu(req->index));
+ /*
+ * The USB transfer is split into qTD transfers. Eeach qTD transfer is
+ * described by a transfer descriptor (the qTD). The qTDs form a linked
+ * list with a queue head (QH).
+ *
+ * Each qTD transfer starts with a new USB packet, i.e. a packet cannot
+ * have its beginning in a qTD transfer and its end in the following
+ * one, so the qTD transfer lengths have to be chosen accordingly.
+ *
+ * Each qTD transfer uses up to QT_BUFFER_CNT data buffers, mapped to
+ * single pages. The first data buffer can start at any offset within a
+ * page (not considering the cache-line alignment issues), while the
+ * following buffers must be page-aligned. There is no alignment
+ * constraint on the size of a qTD transfer.
+ */
+ if (req != NULL)
+ /* 1 qTD will be needed for SETUP, and 1 for ACK. */
+ qtd_count += 1 + 1;
+ if (length > 0 || req == NULL) {
+ /*
+ * Determine the qTD transfer size that will be used for the
+ * data payload (not considering the final qTD transfer, which
+ * may be shorter).
+ *
+ * In order to keep each packet within a qTD transfer, the qTD
+ * transfer size is aligned to EHCI_PAGE_SIZE, which is a
+ * multiple of wMaxPacketSize (except in some cases for
+ * interrupt transfers, see comment in submit_int_msg()).
+ *
+ * By default, i.e. if the input buffer is page-aligned,
+ * QT_BUFFER_CNT full pages will be used.
+ */
+ int xfr_sz = QT_BUFFER_CNT;
+ /*
+ * However, if the input buffer is not page-aligned, the qTD
+ * transfer size will be one page shorter, and the first qTD
+ * data buffer of each transfer will be page-unaligned.
+ */
+ if ((uint32_t)buffer & (EHCI_PAGE_SIZE - 1))
+ xfr_sz--;
+ /* Convert the qTD transfer size to bytes. */
+ xfr_sz *= EHCI_PAGE_SIZE;
+ /*
+ * Determine the number of qTDs that will be required for the
+ * data payload. This value has to be rounded up since the final
+ * qTD transfer may be shorter than the regular qTD transfer
+ * size that has just been computed.
+ */
+ qtd_count += DIV_ROUND_UP(length, xfr_sz);
+ /* ZLPs also need a qTD. */
+ if (!qtd_count)
+ qtd_count++;
+ }
+/*
+ * Threshold value based on the worst-case total size of the qTDs to allocate
+ * for a mass-storage transfer of 65535 blocks of 512 bytes.
+ */
+#if CONFIG_SYS_MALLOC_LEN <= 128 * 1024
+#warning CONFIG_SYS_MALLOC_LEN may be too small for EHCI
+#endif
+ qtd = memalign(USB_DMA_MINALIGN, qtd_count * sizeof(struct qTD));
+ if (qtd == NULL) {
+ printf("unable to allocate TDs\n");
+ return -1;
+ }
+
memset(qh, 0, sizeof(struct QH));
- memset(qtd, 0, QTD_COUNT * sizeof(*qtd));
+ memset(qtd, 0, qtd_count * sizeof(*qtd));
toggle = usb_gettoggle(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe));
}
if (length > 0 || req == NULL) {
- /*
- * Setup request qTD (3.5 in ehci-r10.pdf)
- *
- * qt_next ................ 03-00 H
- * qt_altnext ............. 07-04 H
- * qt_token ............... 0B-08 H
- *
- * [ buffer, buffer_hi ] loaded with "buffer".
- */
- qtd[qtd_counter].qt_next = cpu_to_hc32(QT_NEXT_TERMINATE);
- qtd[qtd_counter].qt_altnext = cpu_to_hc32(QT_NEXT_TERMINATE);
- token = QT_TOKEN_DT(toggle) | QT_TOKEN_TOTALBYTES(length) |
- QT_TOKEN_IOC(req == NULL) | QT_TOKEN_CPAGE(0) |
- QT_TOKEN_CERR(3) | QT_TOKEN_PID(usb_pipein(pipe) ?
- QT_TOKEN_PID_IN : QT_TOKEN_PID_OUT) |
- QT_TOKEN_STATUS(QT_TOKEN_STATUS_ACTIVE);
- qtd[qtd_counter].qt_token = cpu_to_hc32(token);
- if (ehci_td_buffer(&qtd[qtd_counter], buffer, length)) {
- printf("unable to construct DATA TD\n");
- goto fail;
- }
- /* Update previous qTD! */
- *tdp = cpu_to_hc32((uint32_t)&qtd[qtd_counter]);
- tdp = &qtd[qtd_counter++].qt_next;
+ uint8_t *buf_ptr = buffer;
+ int left_length = length;
+
+ do {
+ /*
+ * Determine the size of this qTD transfer. By default,
+ * QT_BUFFER_CNT full pages can be used.
+ */
+ int xfr_bytes = QT_BUFFER_CNT * EHCI_PAGE_SIZE;
+ /*
+ * However, if the input buffer is not page-aligned, the
+ * portion of the first page before the buffer start
+ * offset within that page is unusable.
+ */
+ xfr_bytes -= (uint32_t)buf_ptr & (EHCI_PAGE_SIZE - 1);
+ /*
+ * In order to keep each packet within a qTD transfer,
+ * align the qTD transfer size to EHCI_PAGE_SIZE.
+ */
+ xfr_bytes &= ~(EHCI_PAGE_SIZE - 1);
+ /*
+ * This transfer may be shorter than the available qTD
+ * transfer size that has just been computed.
+ */
+ xfr_bytes = min(xfr_bytes, left_length);
+
+ /*
+ * Setup request qTD (3.5 in ehci-r10.pdf)
+ *
+ * qt_next ................ 03-00 H
+ * qt_altnext ............. 07-04 H
+ * qt_token ............... 0B-08 H
+ *
+ * [ buffer, buffer_hi ] loaded with "buffer".
+ */
+ qtd[qtd_counter].qt_next =
+ cpu_to_hc32(QT_NEXT_TERMINATE);
+ qtd[qtd_counter].qt_altnext =
+ cpu_to_hc32(QT_NEXT_TERMINATE);
+ token = QT_TOKEN_DT(toggle) |
+ QT_TOKEN_TOTALBYTES(xfr_bytes) |
+ QT_TOKEN_IOC(req == NULL) | QT_TOKEN_CPAGE(0) |
+ QT_TOKEN_CERR(3) |
+ QT_TOKEN_PID(usb_pipein(pipe) ?
+ QT_TOKEN_PID_IN : QT_TOKEN_PID_OUT) |
+ QT_TOKEN_STATUS(QT_TOKEN_STATUS_ACTIVE);
+ qtd[qtd_counter].qt_token = cpu_to_hc32(token);
+ if (ehci_td_buffer(&qtd[qtd_counter], buf_ptr,
+ xfr_bytes)) {
+ printf("unable to construct DATA TD\n");
+ goto fail;
+ }
+ /* Update previous qTD! */
+ *tdp = cpu_to_hc32((uint32_t)&qtd[qtd_counter]);
+ tdp = &qtd[qtd_counter++].qt_next;
+ buf_ptr += xfr_bytes;
+ left_length -= xfr_bytes;
+ } while (left_length > 0);
}
if (req != NULL) {
ALIGN_END_ADDR(struct QH, qh_list, 1));
flush_dcache_range((uint32_t)qh, ALIGN_END_ADDR(struct QH, qh, 1));
flush_dcache_range((uint32_t)qtd,
- ALIGN_END_ADDR(struct qTD, qtd, QTD_COUNT));
+ ALIGN_END_ADDR(struct qTD, qtd, qtd_count));
/* Set async. queue head pointer. */
ehci_writel(&hcor->or_asynclistaddr, (uint32_t)qh_list);
invalidate_dcache_range((uint32_t)qh,
ALIGN_END_ADDR(struct QH, qh, 1));
invalidate_dcache_range((uint32_t)qtd,
- ALIGN_END_ADDR(struct qTD, qtd, QTD_COUNT));
+ ALIGN_END_ADDR(struct qTD, qtd, qtd_count));
token = hc32_to_cpu(vtd->qt_token);
if (!(QT_TOKEN_GET_STATUS(token) & QT_TOKEN_STATUS_ACTIVE))
ehci_readl(&hcor->or_portsc[1]));
}
+ free(qtd);
return (dev->status != USB_ST_NOT_PROC) ? 0 : -1;
fail:
+ free(qtd);
return -1;
}
/*
* Interrupt transfers requiring several transactions are not supported
* because bInterval is ignored.
+ *
+ * Also, ehci_submit_async() relies on wMaxPacketSize being a power of 2
+ * if several qTDs are required, while the USB specification does not
+ * constrain this for interrupt transfers. That means that
+ * ehci_submit_async() would support interrupt transfers requiring
+ * several transactions only as long as the transfer size does not
+ * require more than a single qTD.
*/
if (length > usb_maxpacket(dev, pipe)) {
printf("%s: Interrupt transfers requiring several transactions "
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