[PATCH 5.15 114/177] Revert "usb: early: convert to readl_poll_timeout_atomic()"

Greg Kroah-Hartman
2021-12-20T15:13:59Z

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit c4d936efa46d8ea183df16c0f3fa4423327da51d ]

This reverts commit 796eed4b2342c9d6b26c958e92af91253a2390e1.

This change causes boot lockups when using "arlyprintk=xdbc" because
ktime can not be used at this point in time in the boot process. Also,
it is not needed for very small delays like this.

Reported-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Cc: Jann Horn <jannh@google.com>
Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
Fixes: 796eed4b2342 ("usb: early: convert to readl_poll_timeout_atomic()")
Link: https://lore.kernel.org/r/c2b5c9bb-1b75-bf56-3754-b5b18812d65e@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/early/xhci-dbc.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index be4ecbabdd586..6c0434100e38c 100644
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -14,7 +14,6 @@
#include <linux/pci_ids.h>
#include <linux/memblock.h>
#include <linux/io.h>
-#include <linux/iopoll.h>
#include <asm/pci-direct.h>
#include <asm/fixmap.h>
#include <linux/bcd.h>
@@ -136,9 +135,17 @@ static int handshake(void __iomem *ptr, u32 mask, u32 done, int wait, int delay)
{
u32 result;

- return readl_poll_timeout_atomic(ptr, result,
- ((result & mask) == done),
- delay, wait);
+ /* Can not use readl_poll_timeout_atomic() for early boot things */
+ do {
+ result = readl(ptr);
+ result &= mask;
+ if (result == done)
+ return 0;
+ udelay(delay);
+ wait -= delay;
+ } while (wait > 0);
+
+ return -ETIMEDOUT;
}

static void __init xdbc_bios_handoff(void)
--
2.34.1