[PATCH v8 13/26] memory: tegra124: Support interconnect framework

From: Dmitry Osipenko
Date: Tue Nov 10 2020 - 20:15:39 EST

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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@xxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/memory/tegra/Kconfig | 1 +
drivers/memory/tegra/tegra124-emc.c | 338 +++++++++++++++++++++++++++-
drivers/memory/tegra/tegra124.c | 82 ++++++-
3 files changed, 409 insertions(+), 12 deletions(-)

diff --git a/drivers/memory/tegra/Kconfig b/drivers/memory/tegra/Kconfig
index 6265aa39674f..076482e1787b 100644
--- a/drivers/memory/tegra/Kconfig
+++ b/drivers/memory/tegra/Kconfig
@@ -35,6 +35,7 @@ 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 8fb8c1af25c9..46c546f84baa 100644
--- a/drivers/memory/tegra/tegra124-emc.c
+++ b/drivers/memory/tegra/tegra124-emc.c
@@ -12,20 +12,26 @@
#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/mutex.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
+#define EMC_FBIO_CFG5_DRAM_WIDTH_X64 BIT(4)

#define EMC_INTSTATUS 0x0
#define EMC_INTSTATUS_CLKCHANGE_COMPLETE BIT(4)
@@ -461,6 +467,17 @@ struct emc_timing {
u32 emc_zcal_interval;
};

+enum emc_rate_request_type {
+ EMC_RATE_DEBUG,
+ EMC_RATE_ICC,
+ EMC_RATE_TYPE_MAX,
+};
+
+struct emc_rate_request {
+ unsigned long min_rate;
+ unsigned long max_rate;
+};
+
struct tegra_emc {
struct device *dev;

@@ -471,6 +488,7 @@ struct tegra_emc {
struct clk *clk;

enum emc_dram_type dram_type;
+ unsigned int dram_bus_width;
unsigned int dram_num;

struct emc_timing last_timing;
@@ -482,6 +500,17 @@ struct tegra_emc {
unsigned long min_rate;
unsigned long max_rate;
} debugfs;
+
+ struct icc_provider provider;
+
+ /*
+ * There are multiple sources in the EMC driver which could request
+ * a min/max clock rate, these rates are contained in this array.
+ */
+ struct emc_rate_request requested_rate[EMC_RATE_TYPE_MAX];
+
+ /* protect shared rate-change code path */
+ struct mutex rate_lock;
};

/* Timing change sequence functions */
@@ -870,6 +899,14 @@ static void emc_read_current_timing(struct tegra_emc *emc,
static int emc_init(struct tegra_emc *emc)
{
emc->dram_type = readl(emc->regs + EMC_FBIO_CFG5);
+
+ if (emc->dram_type & EMC_FBIO_CFG5_DRAM_WIDTH_X64)
+ emc->dram_bus_width = 64;
+ else
+ emc->dram_bus_width = 32;
+
+ dev_info(emc->dev, "%ubit DRAM bus\n", emc->dram_bus_width);
+
emc->dram_type &= EMC_FBIO_CFG5_DRAM_TYPE_MASK;
emc->dram_type >>= EMC_FBIO_CFG5_DRAM_TYPE_SHIFT;

@@ -1009,6 +1046,83 @@ tegra_emc_find_node_by_ram_code(struct device_node *node, u32 ram_code)
return NULL;
}

+static void tegra_emc_rate_requests_init(struct tegra_emc *emc)
+{
+ unsigned int i;
+
+ for (i = 0; i < EMC_RATE_TYPE_MAX; i++) {
+ emc->requested_rate[i].min_rate = 0;
+ emc->requested_rate[i].max_rate = ULONG_MAX;
+ }
+}
+
+static int emc_request_rate(struct tegra_emc *emc,
+ unsigned long new_min_rate,
+ unsigned long new_max_rate,
+ enum emc_rate_request_type type)
+{
+ struct emc_rate_request *req = emc->requested_rate;
+ unsigned long min_rate = 0, max_rate = ULONG_MAX;
+ unsigned int i;
+ int err;
+
+ /* select minimum and maximum rates among the requested rates */
+ for (i = 0; i < EMC_RATE_TYPE_MAX; i++, req++) {
+ if (i == type) {
+ min_rate = max(new_min_rate, min_rate);
+ max_rate = min(new_max_rate, max_rate);
+ } else {
+ min_rate = max(req->min_rate, min_rate);
+ max_rate = min(req->max_rate, max_rate);
+ }
+ }
+
+ if (min_rate > max_rate) {
+ dev_err_ratelimited(emc->dev, "%s: type %u: out of range: %lu %lu\n",
+ __func__, type, min_rate, max_rate);
+ return -ERANGE;
+ }
+
+ /*
+ * EMC rate-changes should go via OPP API because it manages voltage
+ * changes.
+ */
+ err = dev_pm_opp_set_rate(emc->dev, min_rate);
+ if (err)
+ return err;
+
+ emc->requested_rate[type].min_rate = new_min_rate;
+ emc->requested_rate[type].max_rate = new_max_rate;
+
+ return 0;
+}
+
+static int emc_set_min_rate(struct tegra_emc *emc, unsigned long rate,
+ enum emc_rate_request_type type)
+{
+ struct emc_rate_request *req = &emc->requested_rate[type];
+ int ret;
+
+ mutex_lock(&emc->rate_lock);
+ ret = emc_request_rate(emc, rate, req->max_rate, type);
+ mutex_unlock(&emc->rate_lock);
+
+ return ret;
+}
+
+static int emc_set_max_rate(struct tegra_emc *emc, unsigned long rate,
+ enum emc_rate_request_type type)
+{
+ struct emc_rate_request *req = &emc->requested_rate[type];
+ int ret;
+
+ mutex_lock(&emc->rate_lock);
+ ret = emc_request_rate(emc, req->min_rate, rate, type);
+ mutex_unlock(&emc->rate_lock);
+
+ return ret;
+}
+
/*
* debugfs interface
*
@@ -1081,7 +1195,7 @@ static int tegra_emc_debug_min_rate_set(void *data, u64 rate)
if (!tegra_emc_validate_rate(emc, rate))
return -EINVAL;

- err = clk_set_min_rate(emc->clk, rate);
+ err = emc_set_min_rate(emc, rate, EMC_RATE_DEBUG);
if (err < 0)
return err;

@@ -1111,7 +1225,7 @@ static int tegra_emc_debug_max_rate_set(void *data, u64 rate)
if (!tegra_emc_validate_rate(emc, rate))
return -EINVAL;

- err = clk_set_max_rate(emc->clk, rate);
+ err = emc_set_max_rate(emc, rate, EMC_RATE_DEBUG);
if (err < 0)
return err;

@@ -1129,15 +1243,6 @@ static void emc_debugfs_init(struct device *dev, struct tegra_emc *emc)
unsigned int i;
int err;

- emc->clk = devm_clk_get(dev, "emc");
- if (IS_ERR(emc->clk)) {
- if (PTR_ERR(emc->clk) != -ENODEV) {
- dev_err(dev, "failed to get EMC clock: %ld\n",
- PTR_ERR(emc->clk));
- return;
- }
- }
-
emc->debugfs.min_rate = ULONG_MAX;
emc->debugfs.max_rate = 0;

@@ -1177,6 +1282,195 @@ 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(-EPROBE_DEFER);
+}
+
+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;
+ const 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 sampled on both EMC clock edges.
+ */
+ dram_data_bus_width_bytes = emc->dram_bus_width / 8;
+ do_div(rate, ddr * dram_data_bus_width_bytes);
+ rate = min_t(u64, rate, U32_MAX);
+
+ err = emc_set_min_rate(emc, rate, EMC_RATE_ICC);
+ 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);
+ if (IS_ERR(node)) {
+ err = PTR_ERR(node);
+ 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);
+ if (IS_ERR(node)) {
+ err = PTR_ERR(node);
+ 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)
+{
+ struct opp_table *reg_opp_table = NULL, *clk_opp_table, *hw_opp_table;
+ u32 hw_version = BIT(tegra_sku_info.soc_speedo_id);
+ 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, please update your device tree\n");
+ return -ENODEV;
+ }
+
+ /* voltage scaling is optional */
+ if (device_property_present(emc->dev, "core-supply")) {
+ reg_opp_table = dev_pm_opp_set_regulators(emc->dev, &rname, 1);
+ if (IS_ERR(reg_opp_table))
+ return dev_err_probe(emc->dev, PTR_ERR(reg_opp_table),
+ "failed to set OPP regulator\n");
+ }
+
+ clk_opp_table = dev_pm_opp_set_clkname(emc->dev, NULL);
+ err = PTR_ERR_OR_ZERO(clk_opp_table);
+ if (err) {
+ dev_err(emc->dev, "failed to set OPP clk: %d\n", err);
+ goto put_reg_table;
+ }
+
+ hw_opp_table = dev_pm_opp_set_supported_hw(emc->dev, &hw_version, 1);
+ err = PTR_ERR_OR_ZERO(hw_opp_table);
+ if (err) {
+ dev_err(emc->dev, "failed to set OPP supported HW: %d\n", err);
+ goto put_clk_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_table;
+ }
+
+ dev_info(emc->dev, "OPP HW ver. 0x%x, current clock rate %lu MHz\n",
+ hw_version, clk_get_rate(emc->clk) / 1000000);
+
+ /* first dummy rate-set initializes voltage state */
+ err = dev_pm_opp_set_rate(emc->dev, clk_get_rate(emc->clk));
+ if (err) {
+ dev_err(emc->dev, "failed to initialize OPP clock: %d\n", err);
+ goto remove_table;
+ }
+
+ return 0;
+
+remove_table:
+ dev_pm_opp_of_remove_table(emc->dev);
+put_hw_table:
+ dev_pm_opp_put_supported_hw(hw_opp_table);
+put_clk_table:
+ dev_pm_opp_put_clkname(clk_opp_table);
+put_reg_table:
+ if (reg_opp_table)
+ dev_pm_opp_put_regulators(reg_opp_table);
+
+ return err;
+}
+
+static void devm_tegra_emc_unset_callback(void *data)
+{
+ tegra124_clk_set_emc_callbacks(NULL, NULL);
+}
+
static int tegra_emc_probe(struct platform_device *pdev)
{
struct device_node *np;
@@ -1188,6 +1482,7 @@ static int tegra_emc_probe(struct platform_device *pdev)
if (!emc)
return -ENOMEM;

+ mutex_init(&emc->rate_lock);
emc->dev = &pdev->dev;

emc->regs = devm_platform_ioremap_resource(pdev, 0);
@@ -1223,9 +1518,29 @@ static int tegra_emc_probe(struct platform_device *pdev)
tegra124_clk_set_emc_callbacks(tegra_emc_prepare_timing_change,
tegra_emc_complete_timing_change);

+ err = devm_add_action_or_reset(&pdev->dev, devm_tegra_emc_unset_callback,
+ NULL);
+ if (err)
+ return err;
+
+ emc->clk = devm_clk_get(&pdev->dev, "emc");
+ if (IS_ERR(emc->clk)) {
+ err = PTR_ERR(emc->clk);
+ dev_err(&pdev->dev, "failed to get EMC clock: %d\n", err);
+ return err;
+ }
+
+ err = tegra_emc_opp_table_init(emc);
+ if (err)
+ return err;
+
+ tegra_emc_rate_requests_init(emc);
+
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 +1557,7 @@ 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..459211f50c08 100644
--- a/drivers/memory/tegra/tegra124.c
+++ b/drivers/memory/tegra/tegra124.c
@@ -4,7 +4,8 @@
*/

#include <linux/of.h>
-#include <linux/mm.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>

#include <dt-bindings/memory/tegra124-mc.h>

@@ -1010,6 +1011,83 @@ 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 be high bandwidth pressure during initial filling
+ * 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 struct icc_node_data *
+tegra124_mc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data)
+{
+ struct tegra_mc *mc = icc_provider_to_tegra_mc(data);
+ const struct tegra_mc_client *client;
+ unsigned int i, idx = spec->args[0];
+ struct icc_node_data *ndata;
+ struct icc_node *node;
+
+ list_for_each_entry(node, &mc->provider.nodes, node_list) {
+ if (node->id != idx)
+ continue;
+
+ ndata = kzalloc(sizeof(*ndata), GFP_KERNEL);
+ if (!ndata)
+ return ERR_PTR(-ENOMEM);
+
+ client = &mc->soc->clients[idx];
+ ndata->node = node;
+
+ switch (client->swgroup) {
+ case TEGRA_SWGROUP_DC:
+ case TEGRA_SWGROUP_DCB:
+ case TEGRA_SWGROUP_PTC:
+ case TEGRA_SWGROUP_VI:
+ /* these clients are isochronous by default */
+ ndata->tag = TEGRA_MC_ICC_TAG_ISO;
+ break;
+
+ default:
+ ndata->tag = TEGRA_MC_ICC_TAG_DEFAULT;
+ break;
+ }
+
+ return ndata;
+ }
+
+ for (i = 0; i < mc->soc->num_clients; i++) {
+ if (mc->soc->clients[i].id == idx)
+ return ERR_PTR(-EPROBE_DEFER);
+ }
+
+ dev_err(mc->dev, "invalid ICC client ID %u\n", idx);
+
+ return ERR_PTR(-EINVAL);
+}
+
+static const struct tegra_mc_icc_ops tegra124_mc_icc_ops = {
+ .xlate_extended = tegra124_mc_of_icc_xlate_extended,
+ .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 +1139,7 @@ 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 +1170,6 @@ 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 */
--
2.29.2

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