[U-Boot] [PATCH v2 11/17] usb: Add support for data alignment

[Simon Glass]

CONFIG_USB_EHCI_DATA_ALIGN sets the required alignment of data for
USB packets (e.g. 4 means word-aligned). This is required for Tegra
to operate.

Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v2:
- Tidy code style in USB buffer alignment code
- Display prominent warning when alignment code is triggered

 README                      |    6 ++++++
 drivers/usb/host/ehci-hcd.c |   29 +++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 0 deletions(-)

diff --git a/README b/README
index fda0190..3194846 100644
--- a/README
+++ b/README
@@ -1096,6 +1096,12 @@ The following options need to be configured:
 				May be defined to allow interrupt polling
 				instead of using asynchronous interrupts
 
+		CONFIG_USB_EHCI_DATA_ALIGN sets the required alignment of
+		data for USB packets (e.g. 4 means word-aligned). This is
+		required for Tegra to operate. Since we want all callers to
+		align data for us, we display a warning when the alignment
+		code is triggered.
+
 - USB Device:
 		Define the below if you wish to use the USB console.
 		Once firmware is rebuilt from a serial console issue the
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 2197119..23458b6 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -322,6 +322,24 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer,
 	int timeout;
 	int ret = 0;
 
+#ifdef CONFIG_USB_EHCI_DATA_ALIGN
+	/* In case ehci host requires alignment for buffers */
+	void *align_buf = NULL;
+	void *orig_buf = buffer;
+	int unaligned = (int)buffer & (CONFIG_USB_EHCI_DATA_ALIGN - 1);
+
+	if (unaligned) {
+		printf("EHCI: Unaligned buffer: performance will suffer\n");
+		align_buf = malloc(length + CONFIG_USB_EHCI_DATA_ALIGN);
+		if (!align_buf)
+			return -1;
+		buffer = (void *)(((ulong)align_buf +
+			CONFIG_USB_EHCI_DATA_ALIGN - 1) &
+				~(CONFIG_USB_EHCI_DATA_ALIGN - 1));
+		if (usb_pipeout(pipe))
+			memcpy(buffer, orig_buf, length);
+	}
+#endif
 	debug("dev=%p, pipe=%lx, buffer=%p, length=%d, req=%p\n", dev, pipe,
 	      buffer, length, req);
 	if (req != NULL)
@@ -513,9 +531,20 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer,
 		      ehci_readl(&hcor->or_portsc[1]));
 	}
 
+#ifdef CONFIG_USB_EHCI_DATA_ALIGN
+	if (unaligned) {
+		if (usb_pipein(pipe) && dev->act_len)
+			memcpy(orig_buf, buffer, length);
+		free(align_buf);
+	}
+#endif
 	return (dev->status != USB_ST_NOT_PROC) ? 0 : -1;
 
 fail:
+#ifdef CONFIG_USB_EHCI_DATA_ALIGN
+	if (unaligned)
+		free(align_buf);
+#endif
 	td = (void *)hc32_to_cpu(qh->qh_overlay.qt_next);
 	while (td != (void *)QT_NEXT_TERMINATE) {
 		qh->qh_overlay.qt_next = td->qt_next;
-- 
1.7.3.1