This is a note to let you know that I've just added the patch titled Revert "usb: early: convert to readl_poll_timeout_atomic()" to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: revert-usb-early-convert-to-readl_poll_timeout_atomi.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 1cbf17bc44c9e3787b57cecac5776430e7d8e543 Author: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Date: Fri Dec 17 16:24:30 2021 +0100 Revert "usb: early: convert to readl_poll_timeout_atomic()" [ 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@xxxxxxxxxxxxxxx> Reported-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Jann Horn <jannh@xxxxxxxxxx> Cc: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx> Fixes: 796eed4b2342 ("usb: early: convert to readl_poll_timeout_atomic()") Link: https://lore.kernel.org/r/c2b5c9bb-1b75-bf56-3754-b5b18812d65e@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> 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)