[U-Boot] [PATCH v4 2/6] ehci-hcd.c, musb_core, usb.h: Add USB_DMA_MINALIGN define for cache alignment

[Tom Rini]

The USB spec says that 32 bytes is the minimum required alignment.
However on some platforms we have a larger minimum requirement for cache
coherency.  In those cases, use that value rather than the USB spec
minimum.  We add a cpp check to <usb.h> to define USB_DMA_MINALIGN and
make use of it in ehci-hcd.c and musb_core.h.  We cannot use MAX() here
as we are not allowed to have tests inside of align(...).

Cc: Marek Vasut <marex at denx.de>
Signed-off-by: Tom Rini <trini at ti.com>

--
Changes in v4:
- Re-checking shows we do not need to add alignment to rootdev/hcor/hccr

Changes in v2:
- Move test to <usb.h>, expand comment.
---
 drivers/usb/host/ehci-hcd.c  |    6 +++---
 drivers/usb/musb/musb_core.h |    2 +-
 include/usb.h                |   10 ++++++++++
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 04300be..d34c675 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -34,7 +34,7 @@ struct ehci_hccr *hccr;	/* R/O registers, not need for volatile */
 volatile struct ehci_hcor *hcor;
 
 static uint16_t portreset;
-static struct QH qh_list __attribute__((aligned(32)));
+static struct QH qh_list __attribute__((aligned(USB_DMA_MINALIGN)));
 
 static struct descriptor {
 	struct usb_hub_descriptor hub;
@@ -207,8 +207,8 @@ static int
 ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer,
 		   int length, struct devrequest *req)
 {
-	static struct QH qh __attribute__((aligned(32)));
-	static struct qTD qtd[3] __attribute__((aligned (32)));
+	static struct QH qh __attribute__((aligned(USB_DMA_MINALIGN)));
+	static struct qTD qtd[3] __attribute__((aligned(USB_DMA_MINALIGN)));
 	int qtd_counter = 0;
 
 	volatile struct qTD *vtd;
diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
index a8adcce..e914369 100644
--- a/drivers/usb/musb/musb_core.h
+++ b/drivers/usb/musb/musb_core.h
@@ -145,7 +145,7 @@ struct musb_regs {
 		struct musb_epN_regs epN;
 	} ep[16];
 
-} __attribute__((packed, aligned(32)));
+} __attribute__((packed, aligned(USB_DMA_MINALIGN)));
 #endif
 
 /*
diff --git a/include/usb.h b/include/usb.h
index 6da91e7..ba3d169 100644
--- a/include/usb.h
+++ b/include/usb.h
@@ -29,6 +29,16 @@
 #include <usb_defs.h>
 #include <usbdescriptors.h>
 
+/*
+ * The EHCI spec says that we must align to at least 32 bytes.  However,
+ * some platforms require larger alignment.
+ */
+#if ARCH_DMA_MINALIGN > 32
+#define USB_DMA_MINALIGN	ARCH_DMA_MINALIGN
+#else
+#define USB_DMA_MINALIGN	32
+#endif
+
 /* Everything is aribtrary */
 #define USB_ALTSETTINGALLOC		4
 #define USB_MAXALTSETTING		128	/* Hard limit */
-- 
1.7.9.5