@@ -24,6 +24,7 @@ config TEGRA30_EMC
tristate "NVIDIA Tegra30 External Memory Controller driver"
default y
depends on TEGRA_MC && ARCH_TEGRA_3x_SOC
+ select PM_OPP
help
This driver is for the External Memory Controller (EMC) found on
Tegra30 chips. The EMC controls the external DRAM on the board.
@@ -14,16 +14,21 @@
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/err.h>
+#include <linux/interconnect-provider.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/mutex.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/types.h>
+#include <soc/tegra/common.h>
#include <soc/tegra/fuse.h>
#include "mc.h"
@@ -323,9 +328,21 @@ struct emc_timing {
bool emc_cfg_dyn_self_ref;
};
+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;
struct tegra_mc *mc;
+ struct icc_provider provider;
struct notifier_block clk_nb;
struct clk *clk;
void __iomem *regs;
@@ -352,6 +369,15 @@ struct tegra_emc {
unsigned long min_rate;
unsigned long max_rate;
} debugfs;
+
+ /*
+ * 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;
};
static int emc_seq_update_timing(struct tegra_emc *emc)
@@ -1094,6 +1120,83 @@ static long emc_round_rate(unsigned long rate,
return timing->rate;
}
+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
*
@@ -1177,7 +1280,7 @@ 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;
@@ -1207,7 +1310,7 @@ 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;
@@ -1264,6 +1367,214 @@ static void tegra_emc_debugfs_init(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);
+ const unsigned int dram_data_bus_width_bytes = 4;
+ const unsigned int ddr = 2;
+ int err;
+
+ /*
+ * Tegra30 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.
+ */
+ 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)
+{
+ u32 hw_version = BIT(tegra_sku_info.soc_speedo_id);
+ struct opp_table *clk_opp_table, *hw_opp_table;
+ int err;
+
+ 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);
+ return err;
+ }
+
+ 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) {
+ if (err == -ENODEV)
+ dev_err(emc->dev, "OPP table not found, please update your device tree\n");
+ else
+ 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);
+
+ return err;
+}
+
+static void devm_tegra_emc_unset_callback(void *data)
+{
+ tegra20_clk_set_emc_round_callback(NULL, NULL);
+}
+
+static void devm_tegra_emc_unreg_clk_notifier(void *data)
+{
+ struct tegra_emc *emc = data;
+
+ clk_notifier_unregister(emc->clk, &emc->clk_nb);
+}
+
+static int tegra_emc_init_clk(struct tegra_emc *emc)
+{
+ int err;
+
+ tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
+
+ err = devm_add_action_or_reset(emc->dev, devm_tegra_emc_unset_callback,
+ NULL);
+ if (err)
+ return err;
+
+ emc->clk = devm_clk_get(emc->dev, NULL);
+ if (IS_ERR(emc->clk)) {
+ dev_err(emc->dev, "failed to get EMC clock: %pe\n", emc->clk);
+ return PTR_ERR(emc->clk);
+ }
+
+ err = clk_notifier_register(emc->clk, &emc->clk_nb);
+ if (err) {
+ dev_err(emc->dev, "failed to register clk notifier: %d\n", err);
+ return err;
+ }
+
+ err = devm_add_action_or_reset(emc->dev,
+ devm_tegra_emc_unreg_clk_notifier, emc);
+ if (err)
+ return err;
+
+ return 0;
+}
+
static int tegra_emc_probe(struct platform_device *pdev)
{
struct device_node *np;
@@ -1278,6 +1589,7 @@ static int tegra_emc_probe(struct platform_device *pdev)
if (IS_ERR(emc->mc))
return PTR_ERR(emc->mc);
+ mutex_init(&emc->rate_lock);
emc->clk_nb.notifier_call = emc_clk_change_notify;
emc->dev = &pdev->dev;
@@ -1310,24 +1622,18 @@ static int tegra_emc_probe(struct platform_device *pdev)
return err;
}
- tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
-
- 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);
- goto unset_cb;
- }
+ err = tegra_emc_init_clk(emc);
+ if (err)
+ return err;
- err = clk_notifier_register(emc->clk, &emc->clk_nb);
- if (err) {
- dev_err(&pdev->dev, "failed to register clk notifier: %d\n",
- err);
- goto unset_cb;
- }
+ err = tegra_emc_opp_table_init(emc);
+ if (err)
+ return err;
platform_set_drvdata(pdev, emc);
+ tegra_emc_rate_requests_init(emc);
tegra_emc_debugfs_init(emc);
+ tegra_emc_interconnect_init(emc);
/*
* Don't allow the kernel module to be unloaded. Unloading adds some
@@ -1337,11 +1643,6 @@ static int tegra_emc_probe(struct platform_device *pdev)
try_module_get(THIS_MODULE);
return 0;
-
-unset_cb:
- tegra20_clk_set_emc_round_callback(NULL, NULL);
-
- return err;
}
static int tegra_emc_suspend(struct device *dev)
@@ -1395,6 +1696,7 @@ static struct platform_driver tegra_emc_driver = {
.of_match_table = tegra_emc_of_match,
.pm = &tegra_emc_pm_ops,
.suppress_bind_attrs = true,
+ .sync_state = icc_sync_state,
},
};
module_platform_driver(tegra_emc_driver);
@@ -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/tegra30-mc.h>
@@ -1083,6 +1084,175 @@ static const struct tegra_mc_reset tegra30_mc_resets[] = {
TEGRA30_MC_RESET(VI, 0x200, 0x204, 17),
};
+static void tegra30_mc_tune_client_latency(struct tegra_mc *mc,
+ const struct tegra_mc_client *client,
+ unsigned int bandwidth_mbytes_sec)
+{
+ u32 arb_tolerance_compensation_nsec, arb_tolerance_compensation_div;
+ const struct tegra_mc_la *la = &client->la;
+ unsigned int fifo_size = client->fifo_size;
+ u32 arb_nsec, la_ticks, value;
+
+ /* see 18.4.1 Client Configuration in Tegra3 TRM v03p */
+ if (bandwidth_mbytes_sec)
+ arb_nsec = fifo_size * NSEC_PER_USEC / bandwidth_mbytes_sec;
+ else
+ arb_nsec = U32_MAX;
+
+ /*
+ * Latency allowness should be set with consideration for the module's
+ * latency tolerance and internal buffering capabilities.
+ *
+ * Display memory clients use isochronous transfers and have very low
+ * tolerance to a belated transfers. Hence we need to compensate the
+ * memory arbitration imperfection for them in order to prevent FIFO
+ * underflow condition when memory bus is busy.
+ *
+ * VI clients also need a stronger compensation.
+ */
+ switch (client->swgroup) {
+ case TEGRA_SWGROUP_MPCORE:
+ case TEGRA_SWGROUP_PTC:
+ /*
+ * We always want lower latency for these clients, hence
+ * don't touch them.
+ */
+ return;
+
+ case TEGRA_SWGROUP_DC:
+ case TEGRA_SWGROUP_DCB:
+ arb_tolerance_compensation_nsec = 1050;
+ arb_tolerance_compensation_div = 2;
+ break;
+
+ case TEGRA_SWGROUP_VI:
+ arb_tolerance_compensation_nsec = 1050;
+ arb_tolerance_compensation_div = 1;
+ break;
+
+ default:
+ arb_tolerance_compensation_nsec = 150;
+ arb_tolerance_compensation_div = 1;
+ break;
+ }
+
+ if (arb_nsec > arb_tolerance_compensation_nsec)
+ arb_nsec -= arb_tolerance_compensation_nsec;
+ else
+ arb_nsec = 0;
+
+ arb_nsec /= arb_tolerance_compensation_div;
+
+ /*
+ * Latency allowance is a number of ticks a request from a particular
+ * client may wait in the EMEM arbiter before it becomes a high-priority
+ * request.
+ */
+ la_ticks = arb_nsec / mc->tick;
+ la_ticks = min(la_ticks, la->mask);
+
+ value = mc_readl(mc, la->reg);
+ value &= ~(la->mask << la->shift);
+ value |= la_ticks << la->shift;
+ mc_writel(mc, value, la->reg);
+}
+
+static int tegra30_mc_icc_set(struct icc_node *src, struct icc_node *dst)
+{
+ struct tegra_mc *mc = icc_provider_to_tegra_mc(src->provider);
+ const struct tegra_mc_client *client = &mc->soc->clients[src->id];
+ u64 peak_bandwidth = icc_units_to_bps(src->peak_bw);
+
+ /*
+ * Skip pre-initialization that is done by icc_node_add(), which sets
+ * bandwidth to maximum for all clients before drivers are loaded.
+ *
+ * This doesn't make sense for us because we don't have drivers for all
+ * clients and it's okay to keep configuration left from bootloader
+ * during boot, at least for today.
+ */
+ if (src == dst)
+ return 0;
+
+ /* convert bytes/sec to megabytes/sec */
+ do_div(peak_bandwidth, 1000000);
+
+ tegra30_mc_tune_client_latency(mc, client, peak_bandwidth);
+
+ return 0;
+}
+
+static int tegra30_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 *
+tegra30_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 tegra30_mc_icc_ops = {
+ .xlate_extended = tegra30_mc_of_icc_xlate_extended,
+ .aggregate = tegra30_mc_icc_aggreate,
+ .set = tegra30_mc_icc_set,
+};
+
const struct tegra_mc_soc tegra30_mc_soc = {
.clients = tegra30_mc_clients,
.num_clients = ARRAY_SIZE(tegra30_mc_clients),
@@ -1097,4 +1267,5 @@ const struct tegra_mc_soc tegra30_mc_soc = {
.reset_ops = &tegra_mc_reset_ops_common,
.resets = tegra30_mc_resets,
.num_resets = ARRAY_SIZE(tegra30_mc_resets),
+ .icc_ops = &tegra30_mc_icc_ops,
};