linux-kernel - [PATCH 09/16] staging: gasket: core: switch to relaxed memory-mapped I/O

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Date:   Thu,  9 Aug 2018 20:21:04 -0700
From:   Todd Poynor <toddpoynor@...il.com>
To:     Rob Springer <rspringer@...gle.com>,
        John Joseph <jnjoseph@...gle.com>,
        Ben Chan <benchan@...omium.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        Todd Poynor <toddpoynor@...gle.com>
Subject: [PATCH 09/16] staging: gasket: core: switch to relaxed memory-mapped I/O

From: Todd Poynor <toddpoynor@...gle.com>

Use of readl() is deprecated; readl_relaxed() with appropriate memory
barriers is preferred.  Switch to relaxed reads and writes for better
performance as well.  Memory barriers required for I/O vs. normal
memory access on Apex devices have already been explicitly coded in the
page table routines.

Signed-off-by: Todd Poynor <toddpoynor@...gle.com>
---
 drivers/staging/gasket/gasket_core.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/gasket/gasket_core.h b/drivers/staging/gasket/gasket_core.h
index 275fd0b345b6e..fd7e75b765a6d 100644
--- a/drivers/staging/gasket/gasket_core.h
+++ b/drivers/staging/gasket/gasket_core.h
@@ -590,25 +590,25 @@ const char *gasket_num_name_lookup(uint num,
 static inline ulong gasket_dev_read_64(struct gasket_dev *gasket_dev, int bar,
 				       ulong location)
 {
-	return readq(&gasket_dev->bar_data[bar].virt_base[location]);
+	return readq_relaxed(&gasket_dev->bar_data[bar].virt_base[location]);
 }
 
 static inline void gasket_dev_write_64(struct gasket_dev *dev, u64 value,
 				       int bar, ulong location)
 {
-	writeq(value, &dev->bar_data[bar].virt_base[location]);
+	writeq_relaxed(value, &dev->bar_data[bar].virt_base[location]);
 }
 
 static inline void gasket_dev_write_32(struct gasket_dev *dev, u32 value,
 				       int bar, ulong location)
 {
-	writel(value, &dev->bar_data[bar].virt_base[location]);
+	writel_relaxed(value, &dev->bar_data[bar].virt_base[location]);
 }
 
 static inline u32 gasket_dev_read_32(struct gasket_dev *dev, int bar,
 				     ulong location)
 {
-	return readl(&dev->bar_data[bar].virt_base[location]);
+	return readl_relaxed(&dev->bar_data[bar].virt_base[location]);
 }
 
 static inline void gasket_read_modify_write_64(struct gasket_dev *dev, int bar,
-- 
2.18.0.597.ga71716f1ad-goog