[PATCH v2 2/9] mailbox: Add NVIDIA Tegra XUSB mailbox driver

On Tuesday 26 August 2014 08:57:31 Thierry Reding wrote:

On Mon, Aug 25, 2014 at 01:01:52PM -0600, Stephen Warren wrote:

quoted

On 08/18/2014 11:08 AM, Andrew Bresticker wrote:

[...]

quoted

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+static int tegra_xusb_mbox_probe(struct platform_device *pdev)

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+    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+    if (!res)
+            return -ENODEV;

Should devm_request_mem_region() be called here to claim the region?

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+    mbox->regs = devm_ioremap_nocache(&pdev->dev, res->start,
+                                      resource_size(res));
+    if (!mbox->regs)
+            return -ENOMEM;

Is _nocache required? I don't see other drivers using it. I assume there's
nothing special about the mbox registers.

Most drivers should be using devm_ioremap_resource() which will use the
_nocache variant of devm_ioremap() when appropriate. Usually the region
will not be marked cacheable (IORESOURCE_CACHEABLE) and therefore be
remapped uncached.

Note that ioremap() and ioremap_nocache() are the same. We really shouldn't
ever call ioremap_nocache().

devm_ioremap_resource() and pci_iomap() checking for IORESOURCE_CACHEABLE is
rather silly, since it doesn't call ioremap_cache() in that case.

	Arnd