[PATCH v2 11/22] memory: tegra: Register as interconnect provider

Dmitry Osipenko
2020-03-30T01:10:01Z

Now memory controller is a memory interconnection provider. This allows us
to use interconnect API in order to change memory configuration.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/memory/tegra/mc.c | 118 ++++++++++++++++++++++++++++++++++++++
drivers/memory/tegra/mc.h | 8 +++
include/soc/tegra/mc.h | 3 +
3 files changed, 129 insertions(+)

diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index ec8403557ed4..bcf0478c5f5a 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -591,6 +591,117 @@ static __maybe_unused irqreturn_t tegra20_mc_irq(int irq, void *data)
return IRQ_HANDLED;
}

+static int tegra_mc_icc_set(struct icc_node *src, struct icc_node *dst)
+{
+ return 0;
+}
+
+static int tegra_mc_icc_aggregate(struct icc_node *node,
+ u32 tag, u32 avg_bw, u32 peak_bw,
+ u32 *agg_avg, u32 *agg_peak)
+{
+ *agg_avg = min((u64)avg_bw + (*agg_avg), (u64)U32_MAX);
+ *agg_peak = max(*agg_peak, peak_bw);
+
+ return 0;
+}
+
+/*
+ * 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_onecell_data *data;
+ struct icc_node *node;
+ unsigned int num_nodes;
+ unsigned int i;
+ int err;
+
+ /* older device-trees don't have interconnect properties */
+ if (!of_find_property(mc->dev->of_node, "#interconnect-cells", NULL))
+ return 0;
+
+ num_nodes = mc->soc->num_clients;
+
+ data = devm_kzalloc(mc->dev, struct_size(data, nodes, num_nodes),
+ GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ mc->provider.dev = mc->dev;
+ mc->provider.set = tegra_mc_icc_set;
+ mc->provider.data = data;
+ mc->provider.xlate = of_icc_xlate_onecell;
+ mc->provider.aggregate = tegra_mc_icc_aggregate;
+
+ err = icc_provider_add(&mc->provider);
+ if (err)
+ return err;
+
+ /* create Memory Controller node */
+ node = icc_node_create(TEGRA_ICC_MC);
+ err = PTR_ERR_OR_ZERO(node);
+ if (err)
+ 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 < num_nodes; i++) {
+ /* create MC client node */
+ node = icc_node_create(mc->soc->clients[i].id);
+ err = PTR_ERR_OR_ZERO(node);
+ if (err)
+ 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;
+
+ data->nodes[i] = node;
+ }
+ data->num_nodes = num_nodes;
+
+ 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;
@@ -699,6 +810,13 @@ static int tegra_mc_probe(struct platform_device *pdev)
}
}

+ if (IS_ENABLED(CONFIG_INTERCONNECT)) {
+ err = tegra_mc_interconnect_setup(mc);
+ if (err)
+ dev_err(&pdev->dev, "failed to initialize ICC: %d\n",
+ err);
+ }
+
return 0;
}

diff --git a/drivers/memory/tegra/mc.h b/drivers/memory/tegra/mc.h
index 957c6eb74ff9..bb13747cd96c 100644
--- a/drivers/memory/tegra/mc.h
+++ b/drivers/memory/tegra/mc.h
@@ -114,4 +114,12 @@ extern const struct tegra_mc_soc tegra132_mc_soc;
extern const struct tegra_mc_soc tegra210_mc_soc;
#endif

+/*
+ * These IDs are for internal use of Tegra's ICC, the values are chosen
+ * such that they don't conflict with the device-tree ICC node IDs.
+ */
+#define TEGRA_ICC_EMC 1000
+#define TEGRA_ICC_EMEM 2000
+#define TEGRA_ICC_MC 3000
+
#endif /* MEMORY_TEGRA_MC_H */
diff --git a/include/soc/tegra/mc.h b/include/soc/tegra/mc.h
index 1238e35653d1..71de023f9f47 100644
--- a/include/soc/tegra/mc.h
+++ b/include/soc/tegra/mc.h
@@ -7,6 +7,7 @@
#define __SOC_TEGRA_MC_H__

#include <linux/err.h>
+#include <linux/interconnect-provider.h>
#include <linux/reset-controller.h>
#include <linux/types.h>

@@ -178,6 +179,8 @@ struct tegra_mc {

struct reset_controller_dev reset;

+ struct icc_provider provider;
+
spinlock_t lock;
};

--
2.25.1