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Message-Id: <1253204734-14061-1-git-send-email-vapier@gentoo.org>
Date: Thu, 17 Sep 2009 12:25:34 -0400
From: Mike Frysinger <vapier@...too.org>
To: linux-usb@...r.kernel.org, Felipe Balbi <felipe.balbi@...ia.com>
Cc: linux-kernel@...r.kernel.org,
uclinux-dist-devel@...ckfin.uclinux.org,
Sonic Zhang <sonic.zhang@...log.com>,
Cliff Cai <cliff.cai@...log.com>
Subject: [PATCH 05/12 v2] USB: musb: add notes for Blackfin anomalies
From: Sonic Zhang <sonic.zhang@...log.com>
Add some helpful notes about how the driver works around different
anomalies that exist in the on-chip host controller.
Signed-off-by: Sonic Zhang <sonic.zhang@...log.com>
Signed-off-by: Cliff Cai <cliff.cai@...log.com>
Signed-off-by: Mike Frysinger <vapier@...too.org>
---
v2
- clean up grammar pointed out by Sergei Shtylyov
drivers/usb/musb/blackfin.h | 27 +++++++++++++++++++++++++++
1 files changed, 27 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/musb/blackfin.h b/drivers/usb/musb/blackfin.h
index a240c1e..b49a362 100644
--- a/drivers/usb/musb/blackfin.h
+++ b/drivers/usb/musb/blackfin.h
@@ -14,6 +14,33 @@
* Blackfin specific definitions
*/
+/* Anomalies notes:
+ *
+ * 05000450 - USB DMA Mode 1 Short Packet Data Corruption:
+ * MUSB driver is designed to transfer buffer of N * maxpacket size
+ * in DMA mode 1 and leave the rest of the data to the next
+ * transfer in DMA mode 0, so we never transmit a short packet in
+ * DMA mode 1.
+ *
+ * 05000463 - This anomaly doesn't affect this driver since it
+ * never uses L1 or L2 memory as data destination.
+ *
+ * 05000464 - This anomaly doesn't affect this driver since it
+ * never uses L1 or L2 memory as data source.
+ *
+ * 05000465 - The anomaly can be seen when SCLK is over 100 MHz, and there is
+ * no way to workaround for bulk endpoints. Since the wMaxPackSize
+ * of bulk is less than or equal to 512, while the fifo size of
+ * endpoint 5, 6, 7 is 1024, the double buffer mode is enabled
+ * automatically when these endpoints are used for bulk OUT.
+ *
+ * 05000466 - This anomaly doesn't affect this driver since it never mixes
+ * concurrent DMA and core accesses to the TX endpoint FIFOs.
+ *
+ * 05000467 - The workaround for this anomaly will introduce another
+ * anomaly - 05000465.
+ */
+
#undef DUMP_FIFO_DATA
#ifdef DUMP_FIFO_DATA
static void dump_fifo_data(u8 *buf, u16 len)
--
1.6.5.rc1
--
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