memory: tegra: Add dummy implementation on Tegra194

With the introduction of commit 9365bf0 ("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: 9365bf0 ("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>

Author: thierryreding

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

drivers/memory/tegra/tegra194.c

@@ -1355,6 +1355,7 @@ const struct tegra_mc_soc tegra194_mc_soc = {
 		   MC_INT_SECURITY_VIOLATION | MC_INT_DECERR_EMEM,
 	.has_addr_hi_reg = true,
 	.ops = &tegra186_mc_ops,
+	.icc_ops = &tegra_mc_icc_ops,
 	.ch_intmask = 0x00000f00,
 	.global_intstatus_channel_shift = 8,
 };

drivers/memory/tegra/tegra234.c

@@ -889,27 +889,6 @@ static int tegra234_mc_icc_aggregate(struct icc_node *node, u32 tag, u32 avg_bw,
 	return 0;
 }
 
-static struct icc_node*
-tegra234_mc_of_icc_xlate(struct of_phandle_args *spec, void *data)
-{
-	struct tegra_mc *mc = icc_provider_to_tegra_mc(data);
-	unsigned int cl_id = spec->args[0];
-	struct icc_node *node;
-
-	list_for_each_entry(node, &mc->provider.nodes, node_list) {
-		if (node->id != cl_id)
-			continue;
-
-		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 tegra234_mc_icc_get_init_bw(struct icc_node *node, u32 *avg, u32 *peak)
 {
 	*avg = 0;
@@ -919,7 +898,7 @@ static int tegra234_mc_icc_get_init_bw(struct icc_node *node, u32 *avg, u32 *pea
 }
 
 static const struct tegra_mc_icc_ops tegra234_mc_icc_ops = {
-	.xlate = tegra234_mc_of_icc_xlate,
+	.xlate = tegra_mc_icc_xlate,
 	.aggregate = tegra234_mc_icc_aggregate,
 	.get_bw = tegra234_mc_icc_get_init_bw,
 	.set = tegra234_mc_icc_set,

include/soc/tegra/mc.h

@@ -175,6 +175,9 @@ struct tegra_mc_icc_ops {
 	int (*get_bw)(struct icc_node *node, u32 *avg, u32 *peak);
 };
 
+struct icc_node *tegra_mc_icc_xlate(struct of_phandle_args *spec, void *data);
+extern const struct tegra_mc_icc_ops tegra_mc_icc_ops;
+
 struct tegra_mc_ops {
 	/*
 	 * @probe: Callback to set up SoC-specific bits of the memory controller. This is called