linux-kernel - [PATCH 1/5] lib: devres: Add managed arch_phys_wc

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Message-Id: <20210916181601.9146-2-tzimmermann@suse.de>
Date:   Thu, 16 Sep 2021 20:15:57 +0200
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     airlied@...hat.com, airlied@...ux.ie, daniel@...ll.ch,
        hdegoede@...hat.com, marcan@...can.st, maz@...nel.org,
        akpm@...ux-foundation.org, npiggin@...il.com,
        thunder.leizhen@...wei.com, gregkh@...uxfoundation.org
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Thomas Zimmermann <tzimmermann@...e.de>
Subject: [PATCH 1/5] lib: devres: Add managed arch_phys_wc_add()

Add devm_arch_phys_wc_add() as managed wrapper around arch_phys_wc_add().
Useful for several grahpics drivers that set framebuffer memory to write
combining.

Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>
---
 include/linux/io.h |  2 ++
 lib/devres.c       | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/include/linux/io.h b/include/linux/io.h
index 9595151d800d..fcd8ea79c5df 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -132,6 +132,8 @@ static inline int arch_phys_wc_index(int handle)
 #endif
 #endif
 
+int devm_arch_phys_wc_add(struct device *dev, unsigned long base, unsigned long size);
+
 enum {
 	/* See memremap() kernel-doc for usage description... */
 	MEMREMAP_WB = 1 << 0,
diff --git a/lib/devres.c b/lib/devres.c
index b0e1c6702c71..24d4d849ff67 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -528,3 +528,39 @@ void pcim_iounmap_regions(struct pci_dev *pdev, int mask)
 }
 EXPORT_SYMBOL(pcim_iounmap_regions);
 #endif /* CONFIG_PCI */
+
+static void devm_arch_phys_ac_add_release(struct device *dev, void *res)
+{
+	arch_phys_wc_del(*((int *)res));
+}
+
+/**
+ * devm_arch_phys_wc_add - Managed arch_phys_wc_add()
+ * @dev: Managed device
+ * @base: Memory base address
+ * @size: Size of memory range
+ *
+ * Adds a WC MTRR using arch_phys_wc_add() and sets up a release callback.
+ * See arch_phys_wc_add() for more information.
+ */
+int devm_arch_phys_wc_add(struct device *dev, unsigned long base, unsigned long size)
+{
+	int *mtrr;
+	int ret;
+
+	mtrr = devres_alloc(devm_arch_phys_ac_add_release, sizeof(*mtrr), GFP_KERNEL);
+	if (!mtrr)
+		return -ENOMEM;
+
+	ret = arch_phys_wc_add(base, size);
+	if (ret < 0) {
+		devres_free(mtrr);
+		return ret;
+	}
+
+	*mtrr = ret;
+	devres_add(dev, mtrr);
+
+	return ret;
+}
+EXPORT_SYMBOL(devm_arch_phys_wc_add);
-- 
2.33.0