memory: tegra: Add dummy implementation on Tegra194

With the introduction of commit 9365bf006f53 ("PCI: tegra194: Add
interconnect support in Tegra234"), the PCI driver on Tegra194 and later
requires an interconnect provider. However, a provider is currently only
exposed on Tegra234 and this causes PCI on Tegra194 to defer probe
indefinitely.

Fix this by adding a dummy implementation on Tegra194. This allows nodes
to be provided to interconnect consumers, but doesn't do any bandwidth
accounting or frequency scaling.

Fixes: 9365bf006f53 ("PCI: tegra194: Add interconnect support in Tegra234")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Sumit Gupta <sumitg@nvidia.com>
Tested-by: Sumit Gupta <sumitg@nvidia.com>
Link: https://lore.kernel.org/r/20230629160132.768940-1-thierry.reding@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index 4a750da1c12a..deb6e65b59af 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -755,6 +755,43 @@ const char *const tegra_mc_error_names[8] = {
 	[6] = "SMMU translation error",
 };
 
+struct icc_node *tegra_mc_icc_xlate(struct of_phandle_args *spec, void *data)
+{
+	struct tegra_mc *mc = icc_provider_to_tegra_mc(data);
+	struct icc_node *node;
+
+	list_for_each_entry(node, &mc->provider.nodes, node_list) {
+		if (node->id == spec->args[0])
+			return node;
+	}
+
+	/*
+	 * If a client driver calls devm_of_icc_get() before the MC driver
+	 * is probed, then return EPROBE_DEFER to the client driver.
+	 */
+	return ERR_PTR(-EPROBE_DEFER);
+}
+
+static int tegra_mc_icc_get(struct icc_node *node, u32 *average, u32 *peak)
+{
+	*average = 0;
+	*peak = 0;
+
+	return 0;
+}
+
+static int tegra_mc_icc_set(struct icc_node *src, struct icc_node *dst)
+{
+	return 0;
+}
+
+const struct tegra_mc_icc_ops tegra_mc_icc_ops = {
+	.xlate = tegra_mc_icc_xlate,
+	.aggregate = icc_std_aggregate,
+	.get_bw = tegra_mc_icc_get,
+	.set = tegra_mc_icc_set,
+};
+
 /*
  * Memory Controller (MC) has few Memory Clients that are issuing memory
  * bandwidth allocation requests to the MC interconnect provider. The MC