summaryrefslogtreecommitdiff
path: root/drivers/misc/ioc4.c
diff options
context:
space:
mode:
authorWill Deacon <will.deacon@arm.com>2019-02-22 17:14:59 +0000
committerWill Deacon <will.deacon@arm.com>2019-04-08 12:01:02 +0100
commitfb24ea52f78e0d595852e09e3a55697c8f442189 (patch)
tree00ca29c7b0b8df6258a1ad1faf34f6e838ada26c /drivers/misc/ioc4.c
parent949b8c72768e3a7c69d270962b8a142ee8deec1b (diff)
drivers: Remove explicit invocations of mmiowb()
mmiowb() is now implied by spin_unlock() on architectures that require it, so there is no reason to call it from driver code. This patch was generated using coccinelle: @mmiowb@ @@ - mmiowb(); and invoked as: $ for d in drivers include/linux/qed sound; do \ spatch --include-headers --sp-file mmiowb.cocci --dir $d --in-place; done NOTE: mmiowb() has only ever guaranteed ordering in conjunction with spin_unlock(). However, pairing each mmiowb() removal in this patch with the corresponding call to spin_unlock() is not at all trivial, so there is a small chance that this change may regress any drivers incorrectly relying on mmiowb() to order MMIO writes between CPUs using lock-free synchronisation. If you've ended up bisecting to this commit, you can reintroduce the mmiowb() calls using wmb() instead, which should restore the old behaviour on all architectures other than some esoteric ia64 systems. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/misc/ioc4.c')
-rw-r--r--drivers/misc/ioc4.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/misc/ioc4.c b/drivers/misc/ioc4.c
index ec0832278170..9d0445a567db 100644
--- a/drivers/misc/ioc4.c
+++ b/drivers/misc/ioc4.c
@@ -156,7 +156,6 @@ ioc4_clock_calibrate(struct ioc4_driver_data *idd)
/* Reset to power-on state */
writel(0, &idd->idd_misc_regs->int_out.raw);
- mmiowb();
/* Set up square wave */
int_out.raw = 0;
@@ -164,7 +163,6 @@ ioc4_clock_calibrate(struct ioc4_driver_data *idd)
int_out.fields.mode = IOC4_INT_OUT_MODE_TOGGLE;
int_out.fields.diag = 0;
writel(int_out.raw, &idd->idd_misc_regs->int_out.raw);
- mmiowb();
/* Check square wave period averaged over some number of cycles */
start = ktime_get_ns();