Re: [PATCH 3/5] iommu/tegra-smmu: Use iommu_fwspec in .probe_/.attach_device()

Dmitry Osipenko
2020-09-26T14:48:23Z

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);