Re: [U-Boot] [PATCH v2 2/5] ehci-hcd: Boost transfer speed

Am 20.07.2012 13:26, schrieb Benoît Thébaudeau:

This patch takes advantage of the hardware EHCI qTD queuing mechanism to avoid software overhead and to make transfers as fast as possible.

The only drawback is a call to memalign. However, this is fast compared to the transfer timings, and the heap size to allocate is small, e.g. a little bit more than 100 kB for a transfer length of 65535 packets of 512 bytes.

Tested on i.MX25 and i.MX35. In my test conditions, the speedup was about 15x using page-aligned buffers, which is really appreciable when accessing large files.

Signed-off-by: Benoît Thébaudeau benoit.thebaudeau@advansee.com Cc: Marek Vasut marex@denx.de Cc: Ilya Yanok ilya.yanok@cogentembedded.com Cc: Stefan Herbrechtsmeier stefan@herbrechtsmeier.net

---

Changes for v2:

• Use DIV_ROUND_UP to make code more readable.

.../drivers/usb/host/ehci-hcd.c | 92 ++++++++++++++------ 1 file changed, 63 insertions(+), 29 deletions(-)

diff --git u-boot-usb-1b4bd0e.orig/drivers/usb/host/ehci-hcd.c u-boot-usb-1b4bd0e/drivers/usb/host/ehci-hcd.c index 5b3b906..cf9ab92 100644 --- u-boot-usb-1b4bd0e.orig/drivers/usb/host/ehci-hcd.c +++ u-boot-usb-1b4bd0e/drivers/usb/host/ehci-hcd.c @@ -208,7 +208,8 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer, int length, struct devrequest *req) { ALLOC_ALIGN_BUFFER(struct QH, qh, 1, USB_DMA_MINALIGN);

• ALLOC_ALIGN_BUFFER(struct qTD, qtd, 3, USB_DMA_MINALIGN);

• struct qTD *qtd;

• int qtd_count = 0; int qtd_counter = 0;

  volatile struct qTD *vtd;

@@ -229,8 +230,23 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer, le16_to_cpu(req->value), le16_to_cpu(req->value), le16_to_cpu(req->index));

• if (req != NULL) /* SETUP + ACK */

• qtd_count += 1 + 1;
  

• if (length > 0 || req == NULL) { /* buffer */

• if ((uint32_t)buffer & 4095)		/* page-unaligned */
  

• 	qtd_count += DIV_ROUND_UP(((uint32_t)buffer & 4095) +
  

• 			length, (QT_BUFFER_CNT - 1) * 4096);
  

• else					/* page-aligned */
  

• 	qtd_count += DIV_ROUND_UP(length, QT_BUFFER_CNT * 4096);
  

• }
• 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, 3 * sizeof(*qtd));

• memset(qtd, 0, qtd_count * sizeof(*qtd));

  toggle = usb_gettoggle(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe));

@@ -291,31 +307,46 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer, }

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 = (toggle << 31) |
  

•     (length << 16) |
  

•     ((req == NULL ? 1 : 0) << 15) |
  

•     (0 << 12) |
  

•     (3 << 10) |
  

•     ((usb_pipein(pipe) ? 1 : 0) << 8) | (0x80 << 0);
  

• qtd[qtd_counter].qt_token = cpu_to_hc32(token);
  

• if (ehci_td_buffer(&qtd[qtd_counter], buffer, length) != 0) {
  

• 	printf("unable 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 {
  

• 	int xfr_bytes = min(left_length,
  

• 			    (QT_BUFFER_CNT * 4096 -
  

• 			     ((uint32_t)buf_ptr & 4095)) &
  

• 			    ~4095);
  

Why you align the length to 4096?

• 	/*
  

• 	 * 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 = (toggle << 31) |
  

• 	    (xfr_bytes << 16) |
  

• 	    ((req == NULL ? 1 : 0) << 15) |
  

• 	    (0 << 12) |
  

• 	    (3 << 10) |
  

• 	    ((usb_pipein(pipe) ? 1 : 0) << 8) | (0x80 << 0);
  

• 	qtd[qtd_counter].qt_token = cpu_to_hc32(token);
  

• 	if (ehci_td_buffer(&qtd[qtd_counter], buf_ptr,
  

• 				xfr_bytes) != 0) {
  

• 		printf("unable 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) {

@@ -346,7 +377,8 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer, flush_dcache_range((uint32_t)qh_list, 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, 3));

• flush_dcache_range((uint32_t)qtd,

• 	   ALIGN_END_ADDR(struct qTD, qtd, qtd_count));
  
  

  /* Set async. queue head pointer. */ ehci_writel(&hcor->or_asynclistaddr, (uint32_t)qh_list);

@@ -377,7 +409,7 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer, 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, 3));
  

• 	ALIGN_END_ADDR(struct qTD, qtd, qtd_count));
  
  

  token = hc32_to_cpu(vtd->qt_token); if (!(token & 0x80))

@@ -450,9 +482,11 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer, ehci_readl(&hcor->or_portsc[1])); }

• free(qtd); return (dev->status != USB_ST_NOT_PROC) ? 0 : -1;

  fail:

• free(qtd); return -1; }