lkml.org 
[lkml]   [2019]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.4 194/241] xhci: Convert xhci_handshake() to use readl_poll_timeout_atomic()
Date
From: Andrey Smirnov <andrew.smirnov@gmail.com>

commit f7fac17ca925faa03fc5eb854c081a24075f8bad upstream.

Xhci_handshake() implements the algorithm already captured by
readl_poll_timeout_atomic(). Convert the former to use the latter to
avoid repetition.

Turned out this patch also fixes a bug on the AMD Stoneyridge platform
where usleep(1) sometimes takes over 10ms.
This means a 5 second timeout can easily take over 15 seconds which will
trigger the watchdog and reboot the system.

[Add info about patch fixing a bug to commit message -Mathias]
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Tested-by: Raul E Rangel <rrangel@chromium.org>
Reviewed-by: Raul E Rangel <rrangel@chromium.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/host/xhci.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)

--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -21,6 +21,7 @@
*/

#include <linux/pci.h>
+#include <linux/iopoll.h>
#include <linux/irq.h>
#include <linux/log2.h>
#include <linux/module.h>
@@ -46,7 +47,6 @@ static unsigned int quirks;
module_param(quirks, uint, S_IRUGO);
MODULE_PARM_DESC(quirks, "Bit flags for quirks to be enabled as default");

-/* TODO: copied from ehci-hcd.c - can this be refactored? */
/*
* xhci_handshake - spin reading hc until handshake completes or fails
* @ptr: address of hc register to be read
@@ -63,18 +63,16 @@ MODULE_PARM_DESC(quirks, "Bit flags for
int xhci_handshake(void __iomem *ptr, u32 mask, u32 done, int usec)
{
u32 result;
+ int ret;

- do {
- result = readl(ptr);
- if (result == ~(u32)0) /* card removed */
- return -ENODEV;
- result &= mask;
- if (result == done)
- return 0;
- udelay(1);
- usec--;
- } while (usec > 0);
- return -ETIMEDOUT;
+ ret = readl_poll_timeout_atomic(ptr, result,
+ (result & mask) == done ||
+ result == U32_MAX,
+ 1, usec);
+ if (result == U32_MAX) /* card removed */
+ return -ENODEV;
+
+ return ret;
}

/*

\
 
 \ /
  Last update: 2019-06-09 19:09    [W:0.755 / U:6.308 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site