Re: [PATCH] powerpc/pseries/dlpar: Search DRC index from ibm,drc-indexes for IO add

[Kowshik Jois B S <kowsjois@linux.ibm.com>]

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On 01/05/25 09:40, Haren Myneni wrote:
> IO hotplug add event is handled in the user space with drmgr tool.
> After the device is enabled, the user space uses /sys/kerne/dlpar
> interface with “dt add index <drc_index>” to update the device tree.
> The kernel interface (dlpar_hp_dt_add()) finds the parent node for
> the specified ‘drc_index’ from ibm,drc-info property. But old FW
> provides ibm,drc-indexes property instead of ibm,drc-info.
>
> If the ibm,drc-info is not available, this patch adds changes to
> search ‘drc_index’ from the indexes array in ibm,drc-indexes
> property to support old FW.
>
> Fixes: 02b98ff44a57 ("powerpc/pseries/dlpar: Add device tree nodes for DLPAR IO add")
> Signed-off-by: Haren Myneni<haren@linux.ibm.com>


Haren, Could you please add the below tag:

Reported-by: Kowshik Jois <kowsjois@linux.ibm.com>

Regards,
Kowshik Jois

> ---
>   arch/powerpc/platforms/pseries/dlpar.c | 52 +++++++++++++++++++++++++-
>   1 file changed, 50 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
> index 213aa26dc8b3..979487da6522 100644
> --- a/arch/powerpc/platforms/pseries/dlpar.c
> +++ b/arch/powerpc/platforms/pseries/dlpar.c
> @@ -404,6 +404,45 @@ get_device_node_with_drc_info(u32 index)
>   	return NULL;
>   }
>   
> +static struct device_node *
> +get_device_node_with_drc_indexes(u32 drc_index)
> +{
> +	struct device_node *np = NULL;
> +	u32 nr_indexes, index;
> +	int i, rc;
> +
> +	for_each_node_with_property(np, "ibm,drc-indexes") {
> +		/*
> +		 * First element in the array is the total number of
> +		 * DRC indexes returned.
> +		 */
> +		rc = of_property_read_u32_index(np, "ibm,drc-indexes",
> +				0, &nr_indexes);
> +		if (rc)
> +			goto out_put_np;
> +
> +		/*
> +		 * Retrieve DRC index from the list and return the
> +		 * device node if matched with the specified index.
> +		 */
> +		for (i = 0; i < nr_indexes; i++) {
> +			rc = of_property_read_u32_index(np, "ibm,drc-indexes",
> +							i+1, &index);
> +			if (rc)
> +				goto out_put_np;
> +
> +			if (drc_index == index)
> +				return np;
> +		}
> +	}
> +
> +	return NULL;
> +
> +out_put_np:
> +	of_node_put(np);
> +	return NULL;
> +}
> +
>   static int dlpar_hp_dt_add(u32 index)
>   {
>   	struct device_node *np, *nodes;
> @@ -423,10 +462,19 @@ static int dlpar_hp_dt_add(u32 index)
>   		goto out;
>   	}
>   
> +	/*
> +	 * Recent FW provides ibm,drc-info property. So search
> +	 * for the user specified DRC index from ibm,drc-info
> +	 * property. If this property is not available, search
> +	 * in the indexes array from ibm,drc-indexes property.
> +	 */
>   	np = get_device_node_with_drc_info(index);
>   
> -	if (!np)
> -		return -EIO;
> +	if (!np) {
> +		np = get_device_node_with_drc_indexes(index);
> +		if (!np)
> +			return -EIO;
> +	}
>   
>   	/* Next, configure the connector. */
>   	nodes = dlpar_configure_connector(cpu_to_be32(index), np);

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