Re: [PATCH v2] usb: fsl_udc: errata - postpone freeing current dTD

On Mon, 2012-06-04 at 13:30 +0200, Christoph Fritz wrote:

Hi,

On Mon, 2012-05-21 at 22:04 +0300, Felipe Balbi wrote:

quoted

On Mon, May 21, 2012 at 08:57:22AM +0200, Christoph Fritz wrote:

quoted

USB controller may access a wrong address for the dTD (endpoint transfer
descriptor) and then hang. This happens a lot when doing tests with
g_ether module and iperf, a tool for measuring maximum TCP and UDP
bandwidth.

This hardware bug is explained in detail by errata number 2858 for i.MX23:
http://cache.freescale.com/files/dsp/doc/errata/IMX23CE.pdf

All (?) SOCs with an IP from chipidea suffer from this problem.
mv_udc_core fixes this bug by commit daec765.  There still may be
unfixed drivers.

Signed-off-by: Christoph Fritz <redacted>
Signed-off-by: Christian Hemp <redacted>
---
 drivers/usb/gadget/fsl_udc_core.c |   15 ++++++++++++++-
 1 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/drivers/usb/gadget/fsl_udc_core.c b/drivers/usb/gadget/fsl_udc_core.c
index 55abfb6..72f2139 100644
--- a/drivers/usb/gadget/fsl_udc_core.c
+++ b/drivers/usb/gadget/fsl_udc_core.c

@@ -65,6 +65,8 @@ static struct usb_sys_interface *usb_sys_regs;
 /* it is initialized in probe()  */
 static struct fsl_udc *udc_controller = NULL;
 
+static struct ep_td_struct *last_free_td;

I don't want to see global variables anymore. In fact, please convert
this to the new udc_start()/udc_stop() calls and use the generic
map/unmap routines.

That'll help you get rid of a bunch of useless code on the driver. After
that you should remove all <asm/*> header includes and drop the ARCH
dependency.

You can also drop the big-/little-endian helpers as you can make use of
generic writel()/readl() routines.

Please make sure these series comes in with enough time to reach v3.6
merge window in about 3 months.

You can put this fix together on that series after you drop the global.

Before I came to do the proposed changes, I stumbled upon this:

In file included from drivers/usb/gadget/fsl_udc_core.c:49:
drivers/usb/gadget/fsl_usb2_udc.h: In function ‘get_qh_by_ep’:
drivers/usb/gadget/fsl_usb2_udc.h:585: error: ‘struct fsl_ep’ has no member named ‘desc’
drivers/usb/gadget/fsl_udc_core.c: In function ‘done’:
drivers/usb/gadget/fsl_udc_core.c:187: error: ‘struct fsl_ep’ has no member named ‘desc’
drivers/usb/gadget/fsl_udc_core.c:187: error: ‘struct fsl_ep’ has no member named ‘desc’
<snip>

my proposed regression patch:
---
From: Christoph Fritz <redacted>
Date: Mon, 4 Jun 2012 12:58:21 +0200
Subject: [PATCH] usb: gadget: regression fix - useage of usb_ep

<snip>

After that, I stumbled upon this dmesg:

Freescale High-Speed USB SOC Device Controller driver (Apr 20, 2007)
fsl-usb2-udc fsl-usb2-udc: clk_get("usb") failed
fsl-usb2-udc: probe of fsl-usb2-udc failed with error -2

Sascha, could you give me a hint?

 Thanks,
  -- Christoph