Re: [PATCH] perf/arm-cmn: don't claim resource during ioremap() for CMN700 with ACPI

[Robin Murphy <robin.murphy@arm.com>]

On 2025-02-18 1:21 am, Yin Fengwei wrote:
> Currently, arm-cmn PMU driver assumes ACPI claim resource
> for CMN600 + ACPI. But with CMN700 + ACPI, the device probe
> failed because of resource claim failes when ioremap() is
> called:
> [   10.837300] arm-cmn ARMHC700:00: error -EBUSY: can't request region for resource [mem 0x40000000-0x4fffffff]
> [   10.847310] arm-cmn ARMHC700:00: probe with driver arm-cmn failed with error -16
> [   10.854726] arm-cmn ARMHC700:02: error -EBUSY: can't request region for resource [mem 0x40040000000-0x4004fffffff]
> [   10.865085] arm-cmn ARMHC700:02: probe with driver arm-cmn failed with error -16
> 
> Let CMN700 + ACPI do same as CMN600 + ACPI to allow CMN700
> work in ACPI env.

No, the CMN-600 routine is a special case for CMN-600 having two nested 
memory resources of its own. CMN-700 and everything else only have one 
memory resource, so that is not appropriate. What else is claiming the 
region to cause a conflict?

Thanks,
Robin.

> Signed-off-by: Yin Fengwei <fengwei_yin@linux.alibaba.com>
> ---
> I am also wondering whether we could just drop the CMN600 part id
> check here if ACPI companion device claimed the resource?
> 
>   drivers/perf/arm-cmn.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
> index ef959e66db7c..8b5322a2aa6e 100644
> --- a/drivers/perf/arm-cmn.c
> +++ b/drivers/perf/arm-cmn.c
> @@ -2559,7 +2559,8 @@ static int arm_cmn_probe(struct platform_device *pdev)
>   	cmn->part = (unsigned long)device_get_match_data(cmn->dev);
>   	platform_set_drvdata(pdev, cmn);
>   
> -	if (cmn->part == PART_CMN600 && has_acpi_companion(cmn->dev)) {
> +	if (((cmn->part == PART_CMN600) || (cmn->part == PART_CMN700)) &&
> +			has_acpi_companion(cmn->dev)) {
>   		rootnode = arm_cmn600_acpi_probe(pdev, cmn);
>   	} else {
>   		rootnode = 0;
> @@ -2649,7 +2650,7 @@ MODULE_DEVICE_TABLE(of, arm_cmn_of_match);
>   static const struct acpi_device_id arm_cmn_acpi_match[] = {
>   	{ "ARMHC600", PART_CMN600 },
>   	{ "ARMHC650" },
> -	{ "ARMHC700" },
> +	{ "ARMHC700", PART_CMN700 },
>   	{}
>   };
>   MODULE_DEVICE_TABLE(acpi, arm_cmn_acpi_match);