From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-ee0-f52.google.com ([74.125.83.52]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Uqqds-0000rl-Lu for barebox@lists.infradead.org; Sun, 23 Jun 2013 20:12:09 +0000 Received: by mail-ee0-f52.google.com with SMTP id c50so5608586eek.25 for ; Sun, 23 Jun 2013 13:11:43 -0700 (PDT) Message-ID: <51C7567B.20008@gmail.com> Date: Sun, 23 Jun 2013 22:11:39 +0200 From: Sebastian Hesselbarth MIME-Version: 1.0 References: <1371827718-7928-1-git-send-email-sebastian.hesselbarth@gmail.com> <1371827718-7928-4-git-send-email-sebastian.hesselbarth@gmail.com> <20130623183324.GJ32299@pengutronix.de> In-Reply-To: <20130623183324.GJ32299@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH 3/3] OF: base: add empty property value pointer To: Sascha Hauer Cc: barebox@lists.infradead.org On 06/23/2013 08:33 PM, Sascha Hauer wrote: > On Fri, Jun 21, 2013 at 05:15:18PM +0200, Sebastian Hesselbarth wrote: >> Since property values can be empty, we need property value pointer to >> be non-NULL to distinguish those properties from non-existing properties. >> This adds a static u32 to which empty properties set their value pointer. >> Also, the value memory is only freed, if property length is not zero. >> >> Signed-off-by: Sebastian Hesselbarth >> --- >> Cc: barebox@lists.infradead.org >> --- >> drivers/of/base.c | 6 +++++- >> 1 files changed, 5 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/of/base.c b/drivers/of/base.c >> index 7926d5d..a100a17 100644 >> --- a/drivers/of/base.c >> +++ b/drivers/of/base.c >> @@ -1501,6 +1501,8 @@ struct device_node *of_new_node(struct device_node *parent, const char *name) >> return node; >> } >> >> +static u32 empty_prop_value; >> + >> struct property *of_new_property(struct device_node *node, const char *name, >> const void *data, int len) >> { >> @@ -1515,6 +1517,7 @@ struct property *of_new_property(struct device_node *node, const char *name, >> goto bail_out; >> >> prop->length = len; >> + prop->value =&empty_prop_value; > > This at least breaks of_set_property() and of_free(). Both unconditionally > do a free(pp->value). Sascha, this is patch 3/3, the two functions above are taken care of patch 2/3. > Why do we need this anyway? We can always call of_find_property() to see > if a property exists. Actually, I was preparing to import drivers/of/address.c from linux. of_translate_one uses of_get_property on "ranges". This returns the property's value pointer instead of the property itself, which is NULL for an empty ranges property. Now that you point it out, using of_find_property is also an option. Nevertheless, patches 1 (with your comments applied) and 2 seem sensible to me. Patch 3 is an option to keep it in sync with Linux OF API behavior but is optional. Sebastian _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox