Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [RFC 5/6] powerpc/pci/hotplug: Use common drcinfo parsing
To:     Bjorn Helgaas <helgaas@kernel.org>,
        Michael Bringmann <mwb@linux.vnet.ibm.com>
Cc:     Thomas Falcon <tlfalcon@linux.vnet.ibm.com>,
        linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        Juliet Kim <minkim@us.ibm.com>,
        Paul Mackerras <paulus@samba.org>,
        Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
        linuxppc-dev@lists.ozlabs.org
References: <20181214204914.16435.59083.stgit@powerkvm6.aus.stglabs.ibm.com>
 <20181214205120.16435.46952.stgit@powerkvm6.aus.stglabs.ibm.com>
 <20190115002857.GG33971@google.com>
From:   Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Date:   Thu, 24 Jan 2019 16:29:30 -0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <20190115002857.GG33971@google.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Message-Id: <d49202ed-7886-8dd1-1f9e-801512b49827@linux.vnet.ibm.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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@linux.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@linux.vnet.ibm.com>

> 
> $ ./scripts/get_maintainer.pl -f drivers/pci/hotplug/rpaphp_core.c
> Tyrel Datwyler <tyreld@linux.vnet.ibm.com> (supporter:IBM Power PCI Hotplug Driver for RPA-compliant...)
> Benjamin Herrenschmidt <benh@kernel.crashing.org> (supporter:LINUX FOR POWERPC (32-BIT AND 64-BIT))
> Paul Mackerras <paulus@samba.org> (supporter:LINUX FOR POWERPC (32-BIT AND 64-BIT))
> Michael Ellerman <mpe@ellerman.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);
>>  
>>