Subject: Re: [RFC 5/6] powerpc/pci/hotplug: Use common drcinfo parsing

From: Bjorn Helgaas <[email-masked]>
Date: Tue, 22 Jan 2019 13:58:38 -0600

On Mon, Jan 14, 2019 at 06:28:57PM -0600, Bjorn Helgaas wrote:
> On Fri, Dec 14, 2018 at 02:51:31PM -0600, Michael Bringmann wrote:
> > The implementation of the pseries-specific drc info properties
> > is currently implemented in pseries-specific and non-pseries-specific
> > files.  This patch set uses a new implementation of the device-tree
> > parsing code for the properties.
> > 
> > This patch refactors parsing of the pseries-specific drc-info properties
> > out of rpaphp_core.c to use the common parser.  In the case where an
> > architecture does not use these properties, an __weak copy of the
> > function is provided with dummy return values.  Changes include creating
> > appropriate callback functions and passing callback-specific data
> > blocks into arch_find_drc_match.  All functions that were used just
> > to support the previous parsing implementation have been moved.
> > 
> > Signed-off-by: Michael Bringmann <[email-masked]>
> 
> This is fine with me.  Any rpaphp_core.c maintainers want to comment?
> Tyrel?
> 
> $ ./scripts/get_maintainer.pl -f drivers/pci/hotplug/rpaphp_core.c
> Tyrel Datwyler <[email-masked]> (supporter:IBM Power PCI Hotplug Driver for RPA-compliant...)
> Benjamin Herrenschmidt <[email-masked]> (supporter:LINUX FOR POWERPC (32-BIT AND 64-BIT))
> Paul Mackerras <[email-masked]> (supporter:LINUX FOR POWERPC (32-BIT AND 64-BIT))
> Michael Ellerman <[email-masked]> (supporter:LINUX FOR POWERPC (32-BIT AND 64-BIT))

This looks like part of a larger series, but I only got this patch.  So I
assume you'll route this elsewhere along with the rest of the series.
Here's my ack if it's useful:

Acked-by: Bjorn Helgaas <[email-masked]>

> > ---
> >  drivers/pci/hotplug/rpaphp_core.c |  232 ++++---------------------------------
> >  1 file changed, 28 insertions(+), 204 deletions(-)
> > 
> > diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c
> > index bcd5d35..9ad7384 100644
> > --- a/drivers/pci/hotplug/rpaphp_core.c
> > +++ b/drivers/pci/hotplug/rpaphp_core.c
> > @@ -154,182 +154,18 @@ static enum pci_bus_speed get_max_bus_speed(struct slot *slot)
> >  	return speed;
> >  }
> >  
> > -static int get_children_props(struct device_node *dn, const int **drc_indexes,
> > -		const int **drc_names, const int **drc_types,
> > -		const int **drc_power_domains)
> > -{
> > -	const int *indexes, *names, *types, *domains;
> > -
> > -	indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
> > -	names = of_get_property(dn, "ibm,drc-names", NULL);
> > -	types = of_get_property(dn, "ibm,drc-types", NULL);
> > -	domains = of_get_property(dn, "ibm,drc-power-domains", NULL);
> > -
> > -	if (!indexes || !names || !types || !domains) {
> > -		/* Slot does not have dynamically-removable children */
> > -		return -EINVAL;
> > -	}
> > -	if (drc_indexes)
> > -		*drc_indexes = indexes;
> > -	if (drc_names)
> > -		/* &drc_names[1] contains NULL terminated slot names */
> > -		*drc_names = names;
> > -	if (drc_types)
> > -		/* &drc_types[1] contains NULL terminated slot types */
> > -		*drc_types = types;
> > -	if (drc_power_domains)
> > -		*drc_power_domains = domains;
> > -
> > -	return 0;
> > -}
> > -
> > -
> >  /* Verify the existence of 'drc_name' and/or 'drc_type' within the
> > - * current node.  First obtain it's my-drc-index property.  Next,
> > - * obtain the DRC info from it's parent.  Use the my-drc-index for
> > - * correlation, and obtain/validate the requested properties.
> > + * current node.
> >   */
> >  
> > -static int rpaphp_check_drc_props_v1(struct device_node *dn, char *drc_name,
> > -				char *drc_type, unsigned int my_index)
> > -{
> > -	char *name_tmp, *type_tmp;
> > -	const int *indexes, *names;
> > -	const int *types, *domains;
> > -	int i, rc;
> > -
> > -	rc = get_children_props(dn->parent, &indexes, &names, &types, &domains);
> > -	if (rc < 0) {
> > -		return -EINVAL;
> > -	}
> > -
> > -	name_tmp = (char *) &names[1];
> > -	type_tmp = (char *) &types[1];
> > -
> > -	/* Iterate through parent properties, looking for my-drc-index */
> > -	for (i = 0; i < be32_to_cpu(indexes[0]); i++) {
> > -		if ((unsigned int) indexes[i + 1] == my_index)
> > -			break;
> > -
> > -		name_tmp += (strlen(name_tmp) + 1);
> > -		type_tmp += (strlen(type_tmp) + 1);
> > -	}
> > -
> > -	if (((drc_name == NULL) || (drc_name && !strcmp(drc_name, name_tmp))) &&
> > -	    ((drc_type == NULL) || (drc_type && !strcmp(drc_type, type_tmp))))
> > -		return 0;
> > -
> > -	return -EINVAL;
> > -}
> > -
> > -static int rpaphp_check_drc_props_v2(struct device_node *dn, char *drc_name,
> > -				char *drc_type, unsigned int my_index)
> > -{
> > -	struct property *info;
> > -	unsigned int entries;
> > -	struct of_drc_info drc;
> > -	const __be32 *value;
> > -	char cell_drc_name[MAX_DRC_NAME_LEN];
> > -	int j, fndit;
> > -
> > -	info = of_find_property(dn->parent, "ibm,drc-info", NULL);
> > -	if (info == NULL)
> > -		return -EINVAL;
> > -
> > -	value = of_prop_next_u32(info, NULL, &entries);
> > -	if (!value)
> > -		return -EINVAL;
> > -
> > -	for (j = 0; j < entries; j++) {
> > -		of_read_drc_info_cell(&info, &value, &drc);
> > -
> > -		/* Should now know end of current entry */
> > -
> > -		if (my_index > drc.last_drc_index)
> > -			continue;
> > -
> > -		fndit = 1;
> > -		break;
> > -	}
> > -	/* Found it */
> > -
> > -	if (fndit)
> > -		sprintf(cell_drc_name, "%s%d", drc.drc_name_prefix, 
> > -			my_index);
> > -
> > -	if (((drc_name == NULL) ||
> > -	     (drc_name && !strcmp(drc_name, cell_drc_name))) &&
> > -	    ((drc_type == NULL) ||
> > -	     (drc_type && !strcmp(drc_type, drc.drc_type))))
> > -		return 0;
> > -
> > -	return -EINVAL;
> > -}
> > -
> >  int rpaphp_check_drc_props(struct device_node *dn, char *drc_name,
> >  			char *drc_type)
> >  {
> > -	const unsigned int *my_index;
> > -
> > -	my_index = of_get_property(dn, "ibm,my-drc-index", NULL);
> > -	if (!my_index) {
> > -		/* Node isn't DLPAR/hotplug capable */
> > -		return -EINVAL;
> > -	}
> > -
> > -	if (firmware_has_feature(FW_FEATURE_DRC_INFO))
> > -		return rpaphp_check_drc_props_v2(dn, drc_name, drc_type,
> > -						*my_index);
> > -	else
> > -		return rpaphp_check_drc_props_v1(dn, drc_name, drc_type,
> > -						*my_index);
> > +	return arch_find_drc_match(dn, NULL, drc_type, drc_name,
> > +				true, false, NULL);
> >  }
> >  EXPORT_SYMBOL_GPL(rpaphp_check_drc_props);
> >  
> > -
> > -static int is_php_type(char *drc_type)
> > -{
> > -	unsigned long value;
> > -	char *endptr;
> > -
> > -	/* PCI Hotplug nodes have an integer for drc_type */
> > -	value = simple_strtoul(drc_type, &endptr, 10);
> > -	if (endptr == drc_type)
> > -		return 0;
> > -
> > -	return 1;
> > -}
> > -
> > -/**
> > - * is_php_dn() - return 1 if this is a hotpluggable pci slot, else 0
> > - * @dn: target &device_node
> > - * @indexes: passed to get_children_props()
> > - * @names: passed to get_children_props()
> > - * @types: returned from get_children_props()
> > - * @power_domains:
> > - *
> > - * This routine will return true only if the device node is
> > - * a hotpluggable slot. This routine will return false
> > - * for built-in pci slots (even when the built-in slots are
> > - * dlparable.)
> > - */
> > -static int is_php_dn(struct device_node *dn, const int **indexes,
> > -		const int **names, const int **types, const int **power_domains)
> > -{
> > -	const int *drc_types;
> > -	int rc;
> > -
> > -	rc = get_children_props(dn, indexes, names, &drc_types, power_domains);
> > -	if (rc < 0)
> > -		return 0;
> > -
> > -	if (!is_php_type((char *) &drc_types[1]))
> > -		return 0;
> > -
> > -	*types = drc_types;
> > -	return 1;
> > -}
> > -
> >  /**
> >   * rpaphp_add_slot -- declare a hotplug slot to the hotplug subsystem.
> >   * @dn: device node of slot
> > @@ -346,54 +182,42 @@ static int is_php_dn(struct device_node *dn, const int **indexes,
> >   *
> >   * To remove a slot, it suffices to call rpaphp_deregister_slot().
> >   */
> > -int rpaphp_add_slot(struct device_node *dn)
> > +
> > +static int rpaphp_add_slot_cb(struct device_node *dn,
> > +			u32 drc_index, char *drc_name, char *drc_type,
> > +			u32 drc_power_domain, void *data)
> >  {
> >  	struct slot *slot;
> >  	int retval = 0;
> > -	int i;
> > -	const int *indexes, *names, *types, *power_domains;
> > -	char *name, *type;
> > -
> > -	if (!dn->name || strcmp(dn->name, "pci"))
> > -		return 0;
> > -
> > -	/* If this is not a hotplug slot, return without doing anything. */
> > -	if (!is_php_dn(dn, &indexes, &names, &types, &power_domains))
> > -		return 0;
> > -
> > -	dbg("Entry %s: dn=%pOF\n", __func__, dn);
> >  
> > -	/* register PCI devices */
> > -	name = (char *) &names[1];
> > -	type = (char *) &types[1];
> > -	for (i = 0; i < be32_to_cpu(indexes[0]); i++) {
> > -		int index;
> > +	slot = alloc_slot_struct(dn, drc_index, drc_name, drc_power_domain);
> > +	if (!slot)
> > +		return -ENOMEM;
> >  
> > -		index = be32_to_cpu(indexes[i + 1]);
> > -		slot = alloc_slot_struct(dn, index, name,
> > -					 be32_to_cpu(power_domains[i + 1]));
> > -		if (!slot)
> > -			return -ENOMEM;
> > +	slot->type = simple_strtoul(drc_type, NULL, 10);
> > +	if (retval)
> > +		return -EINVAL;
> >  
> > -		slot->type = simple_strtoul(type, NULL, 10);
> > +	dbg("Found drc-index:0x%x drc-name:%s drc-type:%s\n",
> > +		drc_index, drc_name, drc_type);
> >  
> > -		dbg("Found drc-index:0x%x drc-name:%s drc-type:%s\n",
> > -				index, name, type);
> > +	retval = rpaphp_enable_slot(slot);
> > +	if (!retval)
> > +		retval = rpaphp_register_slot(slot);
> >  
> > -		retval = rpaphp_enable_slot(slot);
> > -		if (!retval)
> > -			retval = rpaphp_register_slot(slot);
> > +	if (retval)
> > +		dealloc_slot_struct(slot);
> >  
> > -		if (retval)
> > -			dealloc_slot_struct(slot);
> > +	return retval;
> > +}
> >  
> > -		name += strlen(name) + 1;
> > -		type += strlen(type) + 1;
> > -	}
> > -	dbg("%s - Exit: rc[%d]\n", __func__, retval);
> > +int rpaphp_add_slot(struct device_node *dn)
> > +{
> > +	if (!dn->name || strcmp(dn->name, "pci"))
> > +		return 0;
> >  
> > -	/* XXX FIXME: reports a failure only if last entry in loop failed */
> > -	return retval;
> > +	return arch_find_drc_match(dn, rpaphp_add_slot_cb,
> > +			NULL, NULL, false, true, NULL);
> >  }
> >  EXPORT_SYMBOL_GPL(rpaphp_add_slot);
> >  
> >