We're going to add interconnect support to the EMC driver. Once this support will be added, the Tegra20 devfreq driver will no longer be able to use clk_round_rate(emc) for building up OPP table. It's quite handy that struct tegra_mc contains memory timings which could be used by the devfreq drivers instead of the clk rate-rounding. The tegra_mc timings are populated by the MC driver only for Tegra30+ SoCs, hence the Tegra20 EMC could populate timings by itself.
Signed-off-by: Dmitry Osipenko digetx@gmail.com --- drivers/memory/tegra/Kconfig | 2 +- drivers/memory/tegra/tegra20-emc.c | 47 ++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/drivers/memory/tegra/Kconfig b/drivers/memory/tegra/Kconfig index c1cad4ce6251..5bf75b316a2f 100644 --- a/drivers/memory/tegra/Kconfig +++ b/drivers/memory/tegra/Kconfig @@ -10,7 +10,7 @@ config TEGRA_MC config TEGRA20_EMC tristate "NVIDIA Tegra20 External Memory Controller driver" default y - depends on ARCH_TEGRA_2x_SOC + depends on TEGRA_MC && ARCH_TEGRA_2x_SOC help This driver is for the External Memory Controller (EMC) found on Tegra20 chips. The EMC controls the external DRAM on the board. diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c index 0baa6590adea..2e310c51c599 100644 --- a/drivers/memory/tegra/tegra20-emc.c +++ b/drivers/memory/tegra/tegra20-emc.c @@ -15,12 +15,15 @@ #include <linux/kernel.h> #include <linux/module.h> #include <linux/of.h> +#include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/sort.h> #include <linux/types.h>
#include <soc/tegra/fuse.h>
+#include "mc.h" + #define EMC_INTSTATUS 0x000 #define EMC_INTMASK 0x004 #define EMC_DBG 0x008 @@ -650,6 +653,38 @@ static void tegra_emc_debugfs_init(struct tegra_emc *emc) emc, &tegra_emc_debug_max_rate_fops); }
+static int tegra_emc_init_mc_timings(struct tegra_emc *emc) +{ + struct tegra_mc_timing *timing; + struct platform_device *pdev; + struct device_node *np; + struct tegra_mc *mc; + unsigned int i; + + np = of_find_compatible_node(NULL, NULL, "nvidia,tegra20-mc-gart"); + if (!np) + return -ENOENT; + + pdev = of_find_device_by_node(np); + of_node_put(np); + if (!pdev) + return -ENOENT; + + mc = platform_get_drvdata(pdev); + if (!mc) + return -EPROBE_DEFER; + + mc->timings = devm_kcalloc(mc->dev, emc->num_timings, sizeof(*timing), + GFP_KERNEL); + if (!mc->timings) + return -ENOMEM; + + for (i = 0; i < emc->num_timings; i++) + mc->timings[mc->num_timings++].rate = emc->timings[i].rate; + + return 0; +} + static int tegra_emc_probe(struct platform_device *pdev) { struct device_node *np; @@ -705,6 +740,18 @@ static int tegra_emc_probe(struct platform_device *pdev) return err; }
+ /* + * Only Tegra30+ SoCs are having Memory Controller timings initialized + * by the MC driver. For Tegra20 we need to populate the MC timings + * from here. The MC timings will be used by the Tegra20 devfreq driver. + */ + err = tegra_emc_init_mc_timings(emc); + if (err) { + dev_err(&pdev->dev, "failed to initialize mc timings: %d\n", + err); + return err; + } + tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
emc->clk = devm_clk_get(&pdev->dev, "emc");