On Thu, Feb 13, 2014 at 03:49:55PM +0000, Ludovic wrote:
> I've created a little libusb perl script to debug the device, and found that
> I could simulate the MIPS bug if I would send a read_download_mem address in
> LE format instead of BE, e.g.:
>
> $dev->control_msg((64 + 0 + 128), 0x92 , 0x82, 0x200, $bytes, 4, 1000);
> => OK returns 01 09 00 b0
>
> $dev->control_msg((64 + 0 + 128), 0x92 , 0x82, 0x0002, $bytes, 4, 1000);
> => BAD returns 06 e4 c9 fb
>
> In the io_ti driver, in read_download_mem(), we have:
>
> be_start_address = cpu_to_be16(start_address);
> status = ti_vread_sync(dev, UMPC_MEMORY_READ,
> (__u16)address_type,
> (__force __u16)be_start_address,
> buffer, read_length);
>
>
> Of course cpu_to_be16() has no effect on MIPS BE, and that's the cause of
> the bug.
> I don't know if it should be replaced with a swab16() or something else, I'm
> not a kernel expert :) and there are a few other lines to fix.
>
> Would could fix this bug, or would give me some advice on how to fix it?
I believe you are right. We cannot use cpu_to_be16 as the wIndex
parameter holding the address is always sent in little-endian byte
order.
Care to test the patch below (against usb-next) on both your LE and BE
machines?
Thanks,
Johan
>From c0a8ce2d0565569a6d8849340111f237eafc1cc2 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@xxxxxxxxx>
Date: Mon, 17 Feb 2014 10:38:43 +0100
Subject: [PATCH] USB: io_ti: fix firmware download on big-endian machines
During firmware download the device expects memory addresses in
big-endian byte order. As the wIndex parameter which hold the address is
sent in little-endian byte order regardless of host byte order, we need
to use swab16 rather than cpu_to_be16.
Reported-by: Ludovic <ldrolez@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/usb/serial/io_ti.c | 35 +++++++++++++++++++++++++----------
1 file changed, 25 insertions(+), 10 deletions(-)
diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index a2db5be9c305..e9d200400550 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -28,6 +28,7 @@
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/serial.h>
+#include <linux/swab.h>
#include <linux/kfifo.h>
#include <linux/ioctl.h>
#include <linux/firmware.h>
@@ -280,7 +281,7 @@ static int read_download_mem(struct usb_device *dev, int start_address,
{
int status = 0;
__u8 read_length;
- __be16 be_start_address;
+ u16 be_start_address;
dev_dbg(&dev->dev, "%s - @ %x for %d\n", __func__, start_address, length);
@@ -296,10 +297,14 @@ static int read_download_mem(struct usb_device *dev, int start_address,
if (read_length > 1) {
dev_dbg(&dev->dev, "%s - @ %x for %d\n", __func__, start_address, read_length);
}
- be_start_address = cpu_to_be16(start_address);
+ /*
+ * NOTE: Must use swab as wIndex is sent in little-endian
+ * byte order regardless of host byte order.
+ */
+ be_start_address = swab16((u16)start_address);
status = ti_vread_sync(dev, UMPC_MEMORY_READ,
(__u16)address_type,
- (__force __u16)be_start_address,
+ be_start_address,
buffer, read_length);
if (status) {
@@ -394,7 +399,7 @@ static int write_i2c_mem(struct edgeport_serial *serial,
struct device *dev = &serial->serial->dev->dev;
int status = 0;
int write_length;
- __be16 be_start_address;
+ u16 be_start_address;
/* We can only send a maximum of 1 aligned byte page at a time */
@@ -409,11 +414,16 @@ static int write_i2c_mem(struct edgeport_serial *serial,
__func__, start_address, write_length);
usb_serial_debug_data(dev, __func__, write_length, buffer);
- /* Write first page */
- be_start_address = cpu_to_be16(start_address);
+ /*
+ * Write first page.
+ *
+ * NOTE: Must use swab as wIndex is sent in little-endian byte order
+ * regardless of host byte order.
+ */
+ be_start_address = swab16((u16)start_address);
status = ti_vsend_sync(serial->serial->dev,
UMPC_MEMORY_WRITE, (__u16)address_type,
- (__force __u16)be_start_address,
+ be_start_address,
buffer, write_length);
if (status) {
dev_dbg(dev, "%s - ERROR %d\n", __func__, status);
@@ -436,11 +446,16 @@ static int write_i2c_mem(struct edgeport_serial *serial,
__func__, start_address, write_length);
usb_serial_debug_data(dev, __func__, write_length, buffer);
- /* Write next page */
- be_start_address = cpu_to_be16(start_address);
+ /*
+ * Write next page.
+ *
+ * NOTE: Must use swab as wIndex is sent in little-endian byte
+ * order regardless of host byte order.
+ */
+ be_start_address = swab16((u16)start_address);
status = ti_vsend_sync(serial->serial->dev, UMPC_MEMORY_WRITE,
(__u16)address_type,
- (__force __u16)be_start_address,
+ be_start_address,
buffer, write_length);
if (status) {
dev_err(dev, "%s - ERROR %d\n", __func__, status);
--
1.8.3.2
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