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From:   Alistair Strachan <astrachan@google.com>
To:     linux-kernel@vger.kernel.org
Cc:     Alistair Strachan <astrachan@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= <arve@android.com>,
        Todd Kjos <tkjos@android.com>,
        Martijn Coenen <maco@android.com>,
        Greg Hartman <ghartman@google.com>, devel@driverdev.osuosl.org,
        kernel-team@android.com
Subject: [PATCH 1/3] staging: Android: vsoc: Create wc kernel mapping for region shm.
Date:   Wed,  2 May 2018 21:45:21 -0700
Message-Id: <20180503044521.156965-1-astrachan@google.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Map the region shm as write-combining instead of uncachable.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Todd Kjos <tkjos@android.com>
Cc: Martijn Coenen <maco@android.com>
Cc: Greg Hartman <ghartman@google.com>
Cc: devel@driverdev.osuosl.org
Cc: kernel-team@android.com
Signed-off-by: Alistair Strachan <astrachan@google.com>
---
 drivers/staging/android/TODO   | 1 -
 drivers/staging/android/vsoc.c | 4 +---
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/staging/android/TODO b/drivers/staging/android/TODO
index 2ea6f97b8f0f..ebd6ba3ae02e 100644
--- a/drivers/staging/android/TODO
+++ b/drivers/staging/android/TODO
@@ -18,7 +18,6 @@ vsoc.c, uapi/vsoc_shm.h
    waiting threads. We should eventually use multiple queues and select the
    queue based on the region.
  - Add debugfs support for examining the permissions of regions.
- - Use ioremap_wc instead of ioremap_nocache.
  - Remove VSOC_WAIT_FOR_INCOMING_INTERRUPT ioctl. This functionality has been
    superseded by the futex and is there for legacy reasons.
 
diff --git a/drivers/staging/android/vsoc.c b/drivers/staging/android/vsoc.c
index 587c66d709b9..794137b7751f 100644
--- a/drivers/staging/android/vsoc.c
+++ b/drivers/staging/android/vsoc.c
@@ -802,9 +802,7 @@ static int vsoc_probe_device(struct pci_dev *pdev,
 
 	dev_info(&pdev->dev, "shared memory @ DMA %p size=0x%zx\n",
 		 (void *)vsoc_dev.shm_phys_start, vsoc_dev.shm_size);
-	/* TODO(ghartman): ioremap_wc should work here */
-	vsoc_dev.kernel_mapped_shm = ioremap_nocache(
-			vsoc_dev.shm_phys_start, vsoc_dev.shm_size);
+	vsoc_dev.kernel_mapped_shm = pci_iomap_wc(pdev, SHARED_MEMORY_BAR, 0);
 	if (!vsoc_dev.kernel_mapped_shm) {
 		dev_err(&vsoc_dev.dev->dev, "cannot iomap region\n");
 		vsoc_remove_device(pdev);