On Mon, Apr 15, 2019 at 05:04:14PM +0100, Suzuki K Poulose wrote:
> The stimulus base for STM device must be listed as the second memory
> resource, followed by the programming base address as described in
> "Section 2.3 Resources" in ACPI for CoreSightTM 1.0 Platform Design
> documen (DEN0067).

Thank you for adding more information.

> 
> Add support for parsing the information for ACPI.
> 
> Cc: Mathieu Poirier <mathieu.poir...@linaro.org>
> Cc: "Rafael J. Wysocki" <r...@rjwysocki.net>
> Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com>
> ---
>  drivers/hwtracing/coresight/coresight-stm.c | 43 
> +++++++++++++++++++++++++++++
>  1 file changed, 43 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-stm.c 
> b/drivers/hwtracing/coresight/coresight-stm.c
> index 2d6ae00..7cf2fe4 100644
> --- a/drivers/hwtracing/coresight/coresight-stm.c
> +++ b/drivers/hwtracing/coresight/coresight-stm.c
> @@ -16,6 +16,7 @@
>   * (C) 2015-2016 Chunyan Zhang <zhang.chun...@linaro.org>
>   */
>  #include <asm/local.h>
> +#include <linux/acpi.h>
>  #include <linux/amba/bus.h>
>  #include <linux/bitmap.h>
>  #include <linux/clk.h>
> @@ -716,10 +717,52 @@ static inline int of_stm_get_stimulus_area(struct 
> device *dev,
>  }
>  #endif
>  
> +#ifdef CONFIG_ACPI
> +static int acpi_stm_get_stimulus_area(struct device *dev, struct resource 
> *res)
> +{
> +     int rc;
> +     bool found_base = false;
> +     struct resource_entry *rent;
> +     LIST_HEAD(res_list);
> +
> +     struct acpi_device *adev = ACPI_COMPANION(dev);
> +
> +     if (!adev)
> +             return -ENODEV;
> +     rc = acpi_dev_get_resources(adev, &res_list, NULL, NULL);
> +     if (rc < 0)
> +             return rc;
> +
> +     rc = -ENOENT;
> +     list_for_each_entry(rent, &res_list, node) {
> +             if (resource_type(rent->res) != IORESOURCE_MEM)
> +                     continue;
> +             if (found_base) {
> +                     *res = *rent->res;
> +                     rc = 0;
> +                     break;
> +             }
> +
> +             found_base = true;
> +     }

I would copy the description in the changelog just before the
list_for_each_entry() loop.

> +
> +     acpi_dev_free_resource_list(&res_list);
> +     return rc;
> +}
> +#else
> +static inline int acpi_stm_get_stimulus_area(struct device *dev,
> +                                          struct resource *res)
> +{
> +     return -ENOENT;
> +}
> +#endif
> +
>  static int stm_get_stimulus_area(struct device *dev, struct resource *res)
>  {
>       if (dev->of_node)

I noticed the direct access of ->of_node in patch 16 and thought it was a little
odd that is_of_node() wasn't used.

>               return of_stm_get_stimulus_area(dev, res);
> +     else if (is_acpi_node(dev->fwnode))
> +             return acpi_stm_get_stimulus_area(dev, res);
>       return -ENOENT;

With the above:

Reviewed-by: Mathieu Poirier <mathieu.poir...@linaro.org>

>  }
>  
> -- 
> 2.7.4
> 

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