[PATCH v6 42/52] memory: tegra124: Support interconnect framework

Dmitry Osipenko
2020-10-25T22:20:45Z

Now Internal and External memory controllers are memory interconnection
providers. This allows us to use interconnect API for tuning of memory
configuration. EMC driver now supports OPPs and DVFS.

Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/memory/tegra/Kconfig | 1 +
drivers/memory/tegra/tegra124-emc.c | 186 +++++++++++++++++++++++++++-
drivers/memory/tegra/tegra124.c | 31 +++++
3 files changed, 216 insertions(+), 2 deletions(-)

diff --git a/drivers/memory/tegra/Kconfig b/drivers/memory/tegra/Kconfig
index 94536dc4c495..3d1ef3ec1a2d 100644
--- a/drivers/memory/tegra/Kconfig
+++ b/drivers/memory/tegra/Kconfig
@@ -34,6 +34,7 @@ config TEGRA124_EMC
tristate "NVIDIA Tegra124 External Memory Controller driver"
default y
depends on TEGRA_MC && ARCH_TEGRA_124_SOC
+ select PM_OPP
help
This driver is for the External Memory Controller (EMC) found on
Tegra124 chips. The EMC controls the external DRAM on the board.
diff --git a/drivers/memory/tegra/tegra124-emc.c b/drivers/memory/tegra/tegra124-emc.c
index 2814b1b4a1d9..bdce7bebe0ef 100644
--- a/drivers/memory/tegra/tegra124-emc.c
+++ b/drivers/memory/tegra/tegra124-emc.c
@@ -12,17 +12,21 @@
#include <linux/clk/tegra.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
+#include <linux/interconnect-provider.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
#include <linux/sort.h>
#include <linux/string.h>

#include <soc/tegra/fuse.h>
#include <soc/tegra/mc.h>

+#include "mc.h"
+
#define EMC_FBIO_CFG5 0x104
#define EMC_FBIO_CFG5_DRAM_TYPE_MASK 0x3
#define EMC_FBIO_CFG5_DRAM_TYPE_SHIFT 0
@@ -482,6 +486,9 @@ struct tegra_emc {
unsigned long min_rate;
unsigned long max_rate;
} debugfs;
+
+ struct opp_table *opp_table;
+ struct icc_provider provider;
};

/* Timing change sequence functions */
@@ -1177,6 +1184,169 @@ static void emc_debugfs_init(struct device *dev, struct tegra_emc *emc)
emc, &tegra_emc_debug_max_rate_fops);
}

+static inline struct tegra_emc *
+to_tegra_emc_provider(struct icc_provider *provider)
+{
+ return container_of(provider, struct tegra_emc, provider);
+}
+
+static struct icc_node_data *
+emc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data)
+{
+ struct icc_provider *provider = data;
+ struct icc_node_data *ndata;
+ struct icc_node *node;
+
+ /* External Memory is the only possible ICC route */
+ list_for_each_entry(node, &provider->nodes, node_list) {
+ if (node->id != TEGRA_ICC_EMEM)
+ continue;
+
+ ndata = kzalloc(sizeof(*ndata), GFP_KERNEL);
+ if (!ndata)
+ return ERR_PTR(-ENOMEM);
+
+ /*
+ * SRC and DST nodes should have matching TAG in order to have
+ * it set by default for a requested path.
+ */
+ ndata->tag = TEGRA_MC_ICC_TAG_ISO;
+ ndata->node = node;
+
+ return ndata;
+ }
+
+ return ERR_PTR(-EINVAL);
+}
+
+static int emc_icc_set(struct icc_node *src, struct icc_node *dst)
+{
+ struct tegra_emc *emc = to_tegra_emc_provider(dst->provider);
+ unsigned long long peak_bw = icc_units_to_bps(dst->peak_bw);
+ unsigned long long avg_bw = icc_units_to_bps(dst->avg_bw);
+ unsigned long long rate = max(avg_bw, peak_bw);
+ unsigned int dram_data_bus_width_bytes = 8;
+ unsigned int ddr = 2;
+ int err;
+
+ /*
+ * Tegra124 EMC runs on a clock rate of SDRAM bus. This means that
+ * EMC clock rate is twice smaller than the peak data rate because
+ * data is sample on both EMC clock edges.
+ */
+ do_div(rate, ddr * dram_data_bus_width_bytes);
+ rate = min_t(u64, rate, U32_MAX);
+
+ err = dev_pm_opp_set_rate(emc->dev, rate);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+static int tegra_emc_interconnect_init(struct tegra_emc *emc)
+{
+ const struct tegra_mc_soc *soc = emc->mc->soc;
+ struct icc_node *node;
+ int err;
+
+ emc->provider.dev = emc->dev;
+ emc->provider.set = emc_icc_set;
+ emc->provider.data = &emc->provider;
+ emc->provider.aggregate = soc->icc_ops->aggregate;
+ emc->provider.xlate_extended = emc_of_icc_xlate_extended;
+
+ err = icc_provider_add(&emc->provider);
+ if (err)
+ goto err_msg;
+
+ /* create External Memory Controller node */
+ node = icc_node_create(TEGRA_ICC_EMC);
+ err = PTR_ERR_OR_ZERO(node);
+ if (err)
+ goto del_provider;
+
+ node->name = "External Memory Controller";
+ icc_node_add(node, &emc->provider);
+
+ /* link External Memory Controller to External Memory (DRAM) */
+ err = icc_link_create(node, TEGRA_ICC_EMEM);
+ if (err)
+ goto remove_nodes;
+
+ /* create External Memory node */
+ node = icc_node_create(TEGRA_ICC_EMEM);
+ err = PTR_ERR_OR_ZERO(node);
+ if (err)
+ goto remove_nodes;
+
+ node->name = "External Memory (DRAM)";
+ icc_node_add(node, &emc->provider);
+
+ return 0;
+
+remove_nodes:
+ icc_nodes_remove(&emc->provider);
+del_provider:
+ icc_provider_del(&emc->provider);
+err_msg:
+ dev_err(emc->dev, "failed to initialize ICC: %d\n", err);
+
+ return err;
+}
+
+static int tegra_emc_opp_table_init(struct tegra_emc *emc)
+{
+ u32 hw_version = BIT(tegra_sku_info.soc_speedo_id);
+ struct opp_table *opp_table;
+ const char *rname = "core";
+ int err;
+
+ /*
+ * Legacy device-trees don't have OPP table and EMC driver isn't
+ * useful in this case.
+ */
+ if (!device_property_present(emc->dev, "operating-points-v2")) {
+ dev_err(emc->dev, "OPP table not found\n");
+ dev_err(emc->dev, "please update your device tree\n");
+ return -ENODEV;
+ }
+
+ /* voltage scaling is optional */
+ if (device_property_present(emc->dev, "core-supply"))
+ emc->opp_table = dev_pm_opp_set_regulators(emc->dev, &rname, 1);
+ else
+ emc->opp_table = dev_pm_opp_get_opp_table(emc->dev);
+
+ if (IS_ERR(emc->opp_table))
+ return dev_err_probe(emc->dev, PTR_ERR(emc->opp_table),
+ "failed to prepare OPP table\n");
+
+ opp_table = dev_pm_opp_set_supported_hw(emc->dev, &hw_version, 1);
+ err = PTR_ERR_OR_ZERO(opp_table);
+ if (err) {
+ dev_err(emc->dev, "failed to set supported HW: %d\n", err);
+ goto put_table;
+ }
+
+ err = dev_pm_opp_of_add_table(emc->dev);
+ if (err) {
+ dev_err(emc->dev, "failed to add OPP table: %d\n", err);
+ goto put_hw;
+ }
+
+ dev_info(emc->dev, "OPP HW ver. 0x%x\n", hw_version);
+
+ return 0;
+
+put_hw:
+ dev_pm_opp_put_supported_hw(emc->opp_table);
+put_table:
+ dev_pm_opp_put_opp_table(emc->opp_table);
+
+ return err;
+}
+
static int tegra_emc_probe(struct platform_device *pdev)
{
struct device_node *np;
@@ -1226,14 +1396,20 @@ static int tegra_emc_probe(struct platform_device *pdev)
return err;
}

- platform_set_drvdata(pdev, emc);
-
tegra124_clk_set_emc_callbacks(tegra_emc_prepare_timing_change,
tegra_emc_complete_timing_change);

+ platform_set_drvdata(pdev, emc);
+
+ err = tegra_emc_opp_table_init(emc);
+ if (err)
+ goto unset_cb;
+
if (IS_ENABLED(CONFIG_DEBUG_FS))
emc_debugfs_init(&pdev->dev, emc);

+ tegra_emc_interconnect_init(emc);
+
/*
* Don't allow the kernel module to be unloaded. Unloading adds some
* extra complexity which doesn't really worth the effort in a case of
@@ -1242,6 +1418,11 @@ static int tegra_emc_probe(struct platform_device *pdev)
try_module_get(THIS_MODULE);

return 0;
+
+unset_cb:
+ tegra124_clk_set_emc_callbacks(NULL, NULL);
+
+ return err;
};

static struct platform_driver tegra_emc_driver = {
@@ -1250,6 +1431,7 @@ static struct platform_driver tegra_emc_driver = {
.name = "tegra-emc",
.of_match_table = tegra_emc_of_match,
.suppress_bind_attrs = true,
+ .sync_state = icc_sync_state,
},
};
module_platform_driver(tegra_emc_driver);
diff --git a/drivers/memory/tegra/tegra124.c b/drivers/memory/tegra/tegra124.c
index e2389573d3c0..b69d76cd0411 100644
--- a/drivers/memory/tegra/tegra124.c
+++ b/drivers/memory/tegra/tegra124.c
@@ -1010,6 +1010,35 @@ static const struct tegra_mc_reset tegra124_mc_resets[] = {
TEGRA124_MC_RESET(GPU, 0x970, 0x974, 2),
};

+static int tegra124_mc_icc_set(struct icc_node *src, struct icc_node *dst)
+{
+ /* TODO: program PTSA */
+ return 0;
+}
+
+static int tegra124_mc_icc_aggreate(struct icc_node *node, u32 tag, u32 avg_bw,
+ u32 peak_bw, u32 *agg_avg, u32 *agg_peak)
+{
+ /*
+ * ISO clients need to reserve extra bandwidth up-front because
+ * there could high bandwidth pressure during initial fulling-up
+ * of the client's FIFO buffers. Secondly, we need to take into
+ * account impurities of the memory subsystem.
+ */
+ if (tag == TEGRA_MC_ICC_TAG_ISO)
+ peak_bw = tegra_mc_scale_percents(peak_bw, 400);
+
+ *agg_avg += avg_bw;
+ *agg_peak = max(*agg_peak, peak_bw);
+
+ return 0;
+}
+
+static const struct tegra_mc_icc_ops tegra124_mc_icc_ops = {
+ .aggregate = tegra124_mc_icc_aggreate,
+ .set = tegra124_mc_icc_set,
+};
+
#ifdef CONFIG_ARCH_TEGRA_124_SOC
static const unsigned long tegra124_mc_emem_regs[] = {
MC_EMEM_ARB_CFG,
@@ -1061,6 +1090,7 @@ const struct tegra_mc_soc tegra124_mc_soc = {
.reset_ops = &tegra_mc_reset_ops_common,
.resets = tegra124_mc_resets,
.num_resets = ARRAY_SIZE(tegra124_mc_resets),
+ .icc_ops = &tegra124_mc_icc_ops,
};
#endif /* CONFIG_ARCH_TEGRA_124_SOC */

@@ -1091,5 +1121,6 @@ const struct tegra_mc_soc tegra132_mc_soc = {
.reset_ops = &tegra_mc_reset_ops_common,
.resets = tegra124_mc_resets,
.num_resets = ARRAY_SIZE(tegra124_mc_resets),
+ .icc_ops = &tegra124_mc_icc_ops,
};
#endif /* CONFIG_ARCH_TEGRA_132_SOC */
--
2.27.0