memory: tegra-mc: Add interconnect framework

Add common SoC-agnostic ICC framework which turns Tegra Memory Controller
into a memory interconnection provider. This allows us to use interconnect
API for tuning of memory configurations.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Peter Geis <pgwipeout@gmail.com>
Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Link: https://lore.kernel.org/r/20201104164923.21238-33-digetx@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

1 files changed, 100 insertions, 0 deletions

diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index 998f9148ecb8..a7e6a8e4c95a 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -639,6 +639,101 @@ static __maybe_unused irqreturn_t tegra20_mc_irq(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+/*
+ * Memory Controller (MC) has few Memory Clients that are issuing memory
+ * bandwidth allocation requests to the MC interconnect provider. The MC
+ * provider aggregates the requests and then sends the aggregated request
+ * up to the External Memory Controller (EMC) interconnect provider which
+ * re-configures hardware interface to External Memory (EMEM) in accordance
+ * to the required bandwidth. Each MC interconnect node represents an
+ * individual Memory Client.
+ *
+ * Memory interconnect topology:
+ *
+ *               +----+
+ * +--------+    |    |
+ * | TEXSRD +--->+    |
+ * +--------+    |    |
+ *               |    |    +-----+    +------+
+ *    ...        | MC +--->+ EMC +--->+ EMEM |
+ *               |    |    +-----+    +------+
+ * +--------+    |    |
+ * | DISP.. +--->+    |
+ * +--------+    |    |
+ *               +----+
+ */
+static int tegra_mc_interconnect_setup(struct tegra_mc *mc)
+{
+	struct icc_node *node;
+	unsigned int i;
+	int err;
+
+	/* older device-trees don't have interconnect properties */
+	if (!device_property_present(mc->dev, "#interconnect-cells") ||
+	    !mc->soc->icc_ops)
+		return 0;
+
+	mc->provider.dev = mc->dev;
+	mc->provider.data = &mc->provider;
+	mc->provider.set = mc->soc->icc_ops->set;
+	mc->provider.aggregate = mc->soc->icc_ops->aggregate;
+	mc->provider.xlate_extended = mc->soc->icc_ops->xlate_extended;
+
+	err = icc_provider_add(&mc->provider);
+	if (err)
+		return err;
+
+	/* create Memory Controller node */
+	node = icc_node_create(TEGRA_ICC_MC);
+	if (IS_ERR(node)) {
+		err = PTR_ERR(node);
+		goto del_provider;
+	}
+
+	node->name = "Memory Controller";
+	icc_node_add(node, &mc->provider);
+
+	/* link Memory Controller to External Memory Controller */
+	err = icc_link_create(node, TEGRA_ICC_EMC);
+	if (err)
+		goto remove_nodes;
+
+	for (i = 0; i < mc->soc->num_clients; i++) {
+		/* create MC client node */
+		node = icc_node_create(mc->soc->clients[i].id);
+		if (IS_ERR(node)) {
+			err = PTR_ERR(node);
+			goto remove_nodes;
+		}
+
+		node->name = mc->soc->clients[i].name;
+		icc_node_add(node, &mc->provider);
+
+		/* link Memory Client to Memory Controller */
+		err = icc_link_create(node, TEGRA_ICC_MC);
+		if (err)
+			goto remove_nodes;
+	}
+
+	/*
+	 * MC driver is registered too early, so early that generic driver
+	 * syncing doesn't work for the MC. But it doesn't really matter
+	 * since syncing works for the EMC drivers, hence we can sync the
+	 * MC driver by ourselves and then EMC will complete syncing of
+	 * the whole ICC state.
+	 */
+	icc_sync_state(mc->dev);
+
+	return 0;
+
+remove_nodes:
+	icc_nodes_remove(&mc->provider);
+del_provider:
+	icc_provider_del(&mc->provider);
+
+	return err;
+}
+
 static int tegra_mc_probe(struct platform_device *pdev)
 {
 	struct resource *res;
@@ -727,6 +822,11 @@ static int tegra_mc_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "failed to register reset controller: %d\n",
 			err);
 
+	err = tegra_mc_interconnect_setup(mc);
+	if (err < 0)
+		dev_err(&pdev->dev, "failed to initialize interconnect: %d\n",
+			err);
+
 	if (IS_ENABLED(CONFIG_TEGRA_IOMMU_SMMU) && mc->soc->smmu) {
 		mc->smmu = tegra_smmu_probe(&pdev->dev, mc->soc->smmu, mc);
 		if (IS_ERR(mc->smmu)) {