26.09.2020 11:07, Nicolin Chen пишет:
...
> +     /* NULL smmu pointer means that SMMU driver is not probed yet */
> +     if (unlikely(!smmu))
> +             return ERR_PTR(-EPROBE_DEFER);

Hello, Nicolin!

Please don't pollute code with likely/unlikely. This is not a
performance-critical code.

...
> -static struct platform_driver tegra_mc_driver = {
> +struct platform_driver tegra_mc_driver = {
>       .driver = {
>               .name = "tegra-mc",
>               .of_match_table = tegra_mc_of_match,
> diff --git a/include/soc/tegra/mc.h b/include/soc/tegra/mc.h
> index 1238e35653d1..49a4cf64c4b9 100644
> --- a/include/soc/tegra/mc.h
> +++ b/include/soc/tegra/mc.h
> @@ -184,4 +184,6 @@ struct tegra_mc {
>  int tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long 
> rate);
>  unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc);
>  
> +extern struct platform_driver tegra_mc_driver;

No global variables, please. See for the example:

https://elixir.bootlin.com/linux/v5.9-rc6/source/drivers/devfreq/tegra20-devfreq.c#L100

The tegra_get_memory_controller() is now needed by multiple Tegra
drivers, I think it should be good to have it added into the MC driver
and then make it globally available for all drivers by making use of
of_find_matching_node_and_match().

diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index e1db209fd2ea..ed1bd6d00aaf 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -43,6 +43,29 @@ static const struct of_device_id tegra_mc_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, tegra_mc_of_match);

+struct tegra_mc *tegra_get_memory_controller(void)
+{
+       struct platform_device *pdev;
+       struct device_node *np;
+       struct tegra_mc *mc;
+
+       np = of_find_matching_node_and_match(NULL, tegra_mc_of_match, NULL);
+       if (!np)
+               return ERR_PTR(-ENOENT);
+
+       pdev = of_find_device_by_node(np);
+       of_node_put(np);
+       if (!pdev)
+               return ERR_PTR(-ENODEV);
+
+       mc = platform_get_drvdata(pdev);
+       if (!mc)
+               return ERR_PTR(-EPROBE_DEFER);
+
+       return mc;
+}
+EXPORT_SYMBOL_GPL(tegra_get_memory_controller);
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