linux-kernel - [PATCH] xhci: Convert xhci_handshake() to use readl_poll

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Date:   Wed,  6 Feb 2019 16:03:08 -0800
From:   Andrey Smirnov <andrew.smirnov@...il.com>
To:     linux-usb@...r.kernel.org
Cc:     Andrey Smirnov <andrew.smirnov@...il.com>,
        Mathias Nyman <mathias.nyman@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] xhci: Convert xhci_handshake() to use readl_poll_timeout()

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

Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
Cc: Mathias Nyman <mathias.nyman@...el.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-usb@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
---
 drivers/usb/host/xhci.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 005e65922608..1b5306001340 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/pci.h>
+#include <linux/iopoll.h>
 #include <linux/irq.h>
 #include <linux/log2.h>
 #include <linux/module.h>
@@ -52,7 +53,6 @@ static bool td_on_ring(struct xhci_td *td, struct xhci_ring *ring)
 	return false;
 }
 
-/* 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
@@ -69,18 +69,16 @@ static bool td_on_ring(struct xhci_td *td, struct xhci_ring *ring)
 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(ptr, result,
+				 (result & mask) == done ||
+				 result == U32_MAX,
+				 1, usec);
+	if (result == U32_MAX)		/* card removed */
+		return -ENODEV;
+
+	return ret;
 }
 
 /*
-- 
2.20.1