Re: [PATCH v7 7/7] cpufreq: dt: Add support for interconnect bandwidth scaling

Sibi Sankar
2020-05-04T20:50:52Z

Hey Georgi,

On 2020-04-24 21:24, Georgi Djakov wrote:
> In addition to clocks and regulators, some devices can scale the
> bandwidth
> of their on-chip interconnect - for example between CPU and DDR memory.
> Add
> support for that, so that platforms which support it can make use of
> it.
>
> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> ---
> v7:
> * Drop using dev_pm_opp_set_paths(), as it has been removed.
> * Add Kconfig dependency on INTERCONNECT, as it can be module.
>
>
> v2:
> https://lore.kernel.org/r/20190423132823.7915-6-georgi.djakov@linaro.org
>
> drivers/cpufreq/Kconfig | 1 +
> drivers/cpufreq/cpufreq-dt.c | 15 +++++++++++++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> index c3e6bd59e920..db2ad54ee67f 100644
> --- a/drivers/cpufreq/Kconfig
> +++ b/drivers/cpufreq/Kconfig
> @@ -217,6 +217,7 @@ config CPUFREQ_DT
>
> config CPUFREQ_DT_PLATDEV
> bool
> + depends on INTERCONNECT || !INTERCONNECT
> help
> This adds a generic DT based cpufreq platdev driver for frequency
> management. This creates a 'cpufreq-dt' platform device, on the
> diff --git a/drivers/cpufreq/cpufreq-dt.c
> b/drivers/cpufreq/cpufreq-dt.c
> index 26fe8dfb9ce6..4ecef3257532 100644
> --- a/drivers/cpufreq/cpufreq-dt.c
> +++ b/drivers/cpufreq/cpufreq-dt.c
> @@ -13,6 +13,7 @@
> #include <linux/cpufreq.h>
> #include <linux/cpumask.h>
> #include <linux/err.h>
> +#include <linux/interconnect.h>
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/pm_opp.h>
> @@ -95,6 +96,7 @@ static int resources_available(void)
> struct device *cpu_dev;
> struct regulator *cpu_reg;
> struct clk *cpu_clk;
> + struct icc_path *cpu_path;
> int ret = 0;
> const char *name;
>
> @@ -121,6 +123,19 @@ static int resources_available(void)
>
> clk_put(cpu_clk);
>
> + cpu_path = of_icc_get(cpu_dev, NULL);
> + ret = PTR_ERR_OR_ZERO(cpu_path);

Wouldn't we want to verify all
available paths instead of just
the first path?

> + if (ret) {
> + if (ret == -EPROBE_DEFER)
> + dev_dbg(cpu_dev, "defer icc path: %d\n", ret);
> + else
> + dev_err(cpu_dev, "failed to get icc path: %d\n", ret);
> +
> + return ret;
> + }
> +
> + icc_put(cpu_path);
> +
> name = find_supply_name(cpu_dev);
> /* Platform doesn't require regulator */
> if (!name)

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.