[PATCH v7 32/47] memory: tegra-mc: Add interconnect framework

Dmitry Osipenko
2020-11-04T16:50:29Z

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.

Tested-by: Peter Geis <pgwipeout@gmail.com>
Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/memory/tegra/Kconfig | 1 +
drivers/memory/tegra/mc.c | 100 +++++++++++++++++++++++++++++++++++
drivers/memory/tegra/mc.h | 22 ++++++++
include/soc/tegra/mc.h | 17 ++++++
4 files changed, 140 insertions(+)

diff --git a/drivers/memory/tegra/Kconfig b/drivers/memory/tegra/Kconfig
index 9f0a96bf9ccc..b38e5255effe 100644
--- a/drivers/memory/tegra/Kconfig
+++ b/drivers/memory/tegra/Kconfig
@@ -3,6 +3,7 @@ config TEGRA_MC
bool "NVIDIA Tegra Memory Controller support"
default y
depends on ARCH_TEGRA
+ select INTERCONNECT
help
This driver supports the Memory Controller (MC) hardware found on
NVIDIA Tegra SoCs.
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)) {
diff --git a/drivers/memory/tegra/mc.h b/drivers/memory/tegra/mc.h
index afa3ba45c9e6..33e40d600592 100644
--- a/drivers/memory/tegra/mc.h
+++ b/drivers/memory/tegra/mc.h
@@ -78,6 +78,20 @@

#define MC_TIMING_UPDATE BIT(0)

+static inline u32 tegra_mc_scale_percents(u64 val, unsigned int percents)
+{
+ val = val * percents;
+ do_div(val, 100);
+
+ return min_t(u64, val, U32_MAX);
+}
+
+static inline struct tegra_mc *
+icc_provider_to_tegra_mc(struct icc_provider *provider)
+{
+ return container_of(provider, struct tegra_mc, provider);
+}
+
static inline u32 mc_readl(struct tegra_mc *mc, unsigned long offset)
{
return readl_relaxed(mc->regs + offset);
@@ -115,4 +129,12 @@ 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 ICC drivers. The ID numbers are
+ * chosen such that they don't conflict with the device-tree ICC node IDs.
+ */
+#define TEGRA_ICC_MC 1000
+#define TEGRA_ICC_EMC 1001
+#define TEGRA_ICC_EMEM 1002
+
#endif /* MEMORY_TEGRA_MC_H */
diff --git a/include/soc/tegra/mc.h b/include/soc/tegra/mc.h
index d9395af98143..43876216de34 100644
--- a/include/soc/tegra/mc.h
+++ b/include/soc/tegra/mc.h
@@ -6,7 +6,9 @@
#ifndef __SOC_TEGRA_MC_H__
#define __SOC_TEGRA_MC_H__

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

@@ -141,6 +143,17 @@ struct tegra_mc_reset_ops {
const struct tegra_mc_reset *rst);
};

+#define TEGRA_MC_ICC_TAG_DEFAULT 0
+#define TEGRA_MC_ICC_TAG_ISO BIT(0)
+
+struct tegra_mc_icc_ops {
+ int (*set)(struct icc_node *src, struct icc_node *dst);
+ int (*aggregate)(struct icc_node *node, u32 tag, u32 avg_bw,
+ u32 peak_bw, u32 *agg_avg, u32 *agg_peak);
+ struct icc_node_data *(*xlate_extended)(struct of_phandle_args *spec,
+ void *data);
+};
+
struct tegra_mc_soc {
const struct tegra_mc_client *clients;
unsigned int num_clients;
@@ -160,6 +173,8 @@ struct tegra_mc_soc {
const struct tegra_mc_reset_ops *reset_ops;
const struct tegra_mc_reset *resets;
unsigned int num_resets;
+
+ const struct tegra_mc_icc_ops *icc_ops;
};

struct tegra_mc {
@@ -178,6 +193,8 @@ struct tegra_mc {

struct reset_controller_dev reset;

+ struct icc_provider provider;
+
spinlock_t lock;
};

--
2.27.0