[PATCH v5 33/36] memory: tegra30-emc: Register as interconnect provider

Dmitry Osipenko
2020-08-14T00:08:11Z

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

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/memory/tegra/tegra30-emc.c | 110 +++++++++++++++++++++++++++++
1 file changed, 110 insertions(+)

diff --git a/drivers/memory/tegra/tegra30-emc.c b/drivers/memory/tegra/tegra30-emc.c
index 0cd39bf5f393..29448d02f750 100644
--- a/drivers/memory/tegra/tegra30-emc.c
+++ b/drivers/memory/tegra/tegra30-emc.c
@@ -14,6 +14,7 @@
#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>
@@ -327,6 +328,7 @@ struct tegra_emc {
struct device *dev;
struct tegra_mc *mc;
struct notifier_block clk_nb;
+ struct icc_provider provider;
struct clk *clk;
void __iomem *regs;
unsigned int irq;
@@ -1264,6 +1266,113 @@ 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 *
+emc_of_icc_xlate(struct of_phandle_args *spec, void *data)
+{
+ struct icc_provider *provider = data;
+ 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)
+ return node;
+ }
+
+ 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 rate = icc_units_to_bps(dst->avg_bw);
+ unsigned int dram_data_bus_width_bytes = 4;
+ unsigned int ddr = 2;
+ int err;
+
+ do_div(rate, ddr * dram_data_bus_width_bytes);
+ rate = min_t(u64, rate, U32_MAX);
+
+ err = clk_set_min_rate(emc->clk, rate);
+ if (err)
+ return err;
+
+ err = clk_set_rate(emc->clk, rate);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+static int emc_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;
+}
+
+static int tegra_emc_interconnect_init(struct tegra_emc *emc)
+{
+ struct icc_node *node;
+ int err;
+
+ /* older device-trees don't have interconnect properties */
+ if (!of_find_property(emc->dev->of_node, "#interconnect-cells", NULL))
+ return 0;
+
+ emc->provider.dev = emc->dev;
+ emc->provider.set = emc_icc_set;
+ emc->provider.data = &emc->provider;
+ emc->provider.xlate = emc_of_icc_xlate;
+ emc->provider.aggregate = emc_icc_aggregate;
+
+ 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_probe(struct platform_device *pdev)
{
struct platform_device *mc;
@@ -1343,6 +1452,7 @@ static int tegra_emc_probe(struct platform_device *pdev)

platform_set_drvdata(pdev, emc);
tegra_emc_debugfs_init(emc);
+ tegra_emc_interconnect_init(emc);

/*
* Don't allow the kernel module to be unloaded. Unloading adds some
--
2.27.0