Message-Id: <09e75552-fe02-a9ef-8f39-4855ee294ec4@linux.vnet.ibm.com>
Date:   Fri, 25 Jan 2019 10:12:07 -0600
From:   Michael Bringmann <mwb@...ux.vnet.ibm.com>
To:     Tyrel Datwyler <tyreld@...ux.vnet.ibm.com>,
        Bjorn Helgaas <helgaas@...nel.org>
Cc:     Thomas Falcon <tlfalcon@...ux.vnet.ibm.com>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        Juliet Kim <minkim@...ibm.com>,
        Paul Mackerras <paulus@...ba.org>,
        linuxppc-dev@...ts.ozlabs.org, nathanl@...ux.vnet.ibm.com
Subject: Re: [RFC 5/6] powerpc/pci/hotplug: Use common drcinfo parsing

Adding Nathan Lynch.

On 1/24/19 6:29 PM, Tyrel Datwyler wrote:
> On 01/14/2019 04:28 PM, 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 <mwb@...ux.vnet.ibm.com>
>>
>> This is fine with me.  Any rpaphp_core.c maintainers want to comment?
>> Tyrel?
> 
> It greatly simplifies the code in rpaphp_core.c, and as far as I can tell the
> refactoring maintains the existing functionality.
> 
> Acked-by: Tyrel Datwyler <tyreld@...ux.vnet.ibm.com>
> 
>>
>> $ ./scripts/get_maintainer.pl -f drivers/pci/hotplug/rpaphp_core.c
>> Tyrel Datwyler <tyreld@...ux.vnet.ibm.com> (supporter:IBM Power PCI Hotplug Driver for RPA-compliant...)
>> Benjamin Herrenschmidt <benh@...nel.crashing.org> (supporter:LINUX FOR POWERPC (32-BIT AND 64-BIT))
>> Paul Mackerras <paulus@...ba.org> (supporter:LINUX FOR POWERPC (32-BIT AND 64-BIT))
>> Michael Ellerman <mpe@...erman.id.au> (supporter:LINUX FOR POWERPC (32-BIT AND 64-BIT))
>>
>>> ---
>>>  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);
>>>  
>>>
> 
> 

-- 
Michael W. Bringmann
Linux I/O, Networking and Security Development
IBM Corporation
Tie-Line  363-5196
External: (512) 286-5196
Cell:       (512) 466-0650
mwb@...ux.vnet.ibm.com

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