On Friday 03 January 2014, Gregory CLEMENT wrote:

All the mvebu SoCs have information related to their variant and
revision that can be read from the PCI control register.

This patch adds support for Armada XP and Armada 370. This reading of
the revision and the ID are done before the PCI initialization to
avoid any conflicts. Once these data are retrieved, the resources are
freed to let the PCI subsystem use it.

I like the idea of identifying the soc version for any number of
reasons, but I would hope there was some way of doing this that didn't
involve probing the PCI device. I know this is the traditional way
on orion/kirkwood/dove/... but it always felt wrong to me.

+static u32 soc_dev_id;
+static u32 soc_rev;
+static bool is_id_valid;

Would it be reasonable to reuse the global "system_rev" variable for this
rather than a platform specific exported function?

+static const struct of_device_id mvebu_pcie_of_match_table[] = {
+	{ .compatible = "marvell,armada-xp-pcie", },
+	{ .compatible = "marvell,armada-370-pcie", },
+	{},
+};
+
+int mvebu_get_soc_id(u32 *dev, u32 *rev)
+{
+	if (is_id_valid) {
+		*dev = soc_dev_id;
+		*rev = soc_rev;
+		return 0;
+	} else
+		return -1;
+}
+
+EXPORT_SYMBOL(mvebu_get_soc_id);

Maybe EXPORT_SYMBOL_GPL, out of principle?

+static int __init mvebu_soc_id_init(void)
+{
+	struct device_node *np;
+	int ret = 0;
+
+	np = of_find_matching_node(NULL, mvebu_pcie_of_match_table);
+	if (np) {
+		void __iomem *pci_base;
+		struct clk *clk;
+		/*
+		 * ID and revision are available from any port, so we
+		 * just pick the first one
+		 */
+		struct device_node *child = of_get_next_child(np, NULL);

I guess all this will fail if for some reason the PCIe node is not
present on machines that don't use PCIe.