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    Subject[PATCH v2 17/22] memory: tegra30-emc: Register as interconnect provider
    Date
    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 | 115 +++++++++++++++++++++++++++++
    1 file changed, 115 insertions(+)

    diff --git a/drivers/memory/tegra/tegra30-emc.c b/drivers/memory/tegra/tegra30-emc.c
    index 69698665d431..5a4106173a75 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 +1266,112 @@ 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_onecell(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_onecell;
    + emc->provider.aggregate = emc_icc_aggregate;
    +
    + err = icc_provider_add(&emc->provider);
    + if (err)
    + return err;
    +
    + /* 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);
    +
    + return err;
    +}
    +
    static int tegra_emc_probe(struct platform_device *pdev)
    {
    struct platform_device *mc;
    @@ -1344,6 +1452,13 @@ static int tegra_emc_probe(struct platform_device *pdev)
    platform_set_drvdata(pdev, emc);
    tegra_emc_debugfs_init(emc);

    + if (IS_ENABLED(CONFIG_INTERCONNECT)) {
    + err = tegra_emc_interconnect_init(emc);
    + if (err)
    + dev_err(&pdev->dev, "failed to initialize ICC: %d\n",
    + err);
    + }
    +
    return 0;

    unset_cb:
    --
    2.25.1
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