| Message ID | 1398707877-22596-2-git-send-email-pawel.moll@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Apr 28, 2014 at 12:57 PM, Pawel Moll <pawel.moll@arm.com> wrote: > In "Device Tree powered" systems, platform devices are usually > massively populated with of_platform_populate() call, executed > at some level of initcalls, either by generic architecture > or by platform-specific code. > > There are situations though where certain devices must be > created (and bound with drivers) before all the others. > This presents a challenge, as devices created explicitly > would be created again by of_platform_populate(). > > This patch tries to solve that issue in a generic way, > adding a "populated" flag for a DT node description. > Once set, this device will never be created again via > of_* API, so of_platform_populate() will skip such nodes > (and its children) in a similar way to the non-available > ones. > > Cc: devicetree@vger.kernel.org > Signed-off-by: Pawel Moll <pawel.moll@arm.com> > --- > drivers/of/platform.c | 10 ++++++++-- > include/linux/of.h | 1 + > 2 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 404d1da..0ae757a 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -204,7 +204,8 @@ static struct platform_device *of_platform_device_create_pdata( > { > struct platform_device *dev; > > - if (!of_device_is_available(np)) > + if (!of_device_is_available(np) || > + of_node_check_flag(np, OF_POPULATED)) This and the amba case should be a test_and_set operation to avoid a race condition. Rob
On Mon, 28 Apr 2014 13:02:28 -0500, Rob Herring <robherring2@gmail.com> wrote: > On Mon, Apr 28, 2014 at 12:57 PM, Pawel Moll <pawel.moll@arm.com> wrote: > > In "Device Tree powered" systems, platform devices are usually > > massively populated with of_platform_populate() call, executed > > at some level of initcalls, either by generic architecture > > or by platform-specific code. > > > > There are situations though where certain devices must be > > created (and bound with drivers) before all the others. > > This presents a challenge, as devices created explicitly > > would be created again by of_platform_populate(). > > > > This patch tries to solve that issue in a generic way, > > adding a "populated" flag for a DT node description. > > Once set, this device will never be created again via > > of_* API, so of_platform_populate() will skip such nodes > > (and its children) in a similar way to the non-available > > ones. > > > > Cc: devicetree@vger.kernel.org > > Signed-off-by: Pawel Moll <pawel.moll@arm.com> > > --- > > drivers/of/platform.c | 10 ++++++++-- > > include/linux/of.h | 1 + > > 2 files changed, 9 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > > index 404d1da..0ae757a 100644 > > --- a/drivers/of/platform.c > > +++ b/drivers/of/platform.c > > @@ -204,7 +204,8 @@ static struct platform_device *of_platform_device_create_pdata( > > { > > struct platform_device *dev; > > > > - if (!of_device_is_available(np)) > > + if (!of_device_is_available(np) || > > + of_node_check_flag(np, OF_POPULATED)) > > This and the amba case should be a test_and_set operation to avoid a > race condition. Yes. It is an unlikely condition at the time that Pawel is handling, but it should also work for later calls to of_platform_populate() which may happen at runtime and in parallel. g.
On Tue, 2014-04-29 at 13:56 +0100, Grant Likely wrote: > > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > > > index 404d1da..0ae757a 100644 > > > --- a/drivers/of/platform.c > > > +++ b/drivers/of/platform.c > > > @@ -204,7 +204,8 @@ static struct platform_device *of_platform_device_create_pdata( > > > { > > > struct platform_device *dev; > > > > > > - if (!of_device_is_available(np)) > > > + if (!of_device_is_available(np) || > > > + of_node_check_flag(np, OF_POPULATED)) > > > > This and the amba case should be a test_and_set operation to avoid a > > race condition. > > Yes. It is an unlikely condition at the time that Pawel is handling, but > it should also work for later calls to of_platform_populate() which may > happen at runtime and in parallel. Sure thing, will fix. Thanks! Pawel
diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 404d1da..0ae757a 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -204,7 +204,8 @@ static struct platform_device *of_platform_device_create_pdata( { struct platform_device *dev; - if (!of_device_is_available(np)) + if (!of_device_is_available(np) || + of_node_check_flag(np, OF_POPULATED)) return NULL; dev = of_device_alloc(np, bus_id, parent); @@ -230,6 +231,8 @@ static struct platform_device *of_platform_device_create_pdata( return NULL; } + of_node_set_flag(np, OF_POPULATED); + return dev; } @@ -262,7 +265,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node, pr_debug("Creating amba device %s\n", node->full_name); - if (!of_device_is_available(node)) + if (!of_device_is_available(node) || + of_node_check_flag(node, OF_POPULATED)) return NULL; dev = amba_device_alloc(NULL, 0, 0); @@ -305,6 +309,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node, goto err_free; } + of_node_set_flag(node, OF_POPULATED); + return dev; err_free: diff --git a/include/linux/of.h b/include/linux/of.h index 3bad8d1..fd3aaee 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -197,6 +197,7 @@ static inline unsigned long of_read_ulong(const __be32 *cell, int size) /* flag descriptions */ #define OF_DYNAMIC 1 /* node and properties were allocated via kmalloc */ #define OF_DETACHED 2 /* node has been detached from the device tree */ +#define OF_POPULATED 3 /* device already created for the node */ #define OF_IS_DYNAMIC(x) test_bit(OF_DYNAMIC, &x->_flags) #define OF_MARK_DYNAMIC(x) set_bit(OF_DYNAMIC, &x->_flags)
In "Device Tree powered" systems, platform devices are usually massively populated with of_platform_populate() call, executed at some level of initcalls, either by generic architecture or by platform-specific code. There are situations though where certain devices must be created (and bound with drivers) before all the others. This presents a challenge, as devices created explicitly would be created again by of_platform_populate(). This patch tries to solve that issue in a generic way, adding a "populated" flag for a DT node description. Once set, this device will never be created again via of_* API, so of_platform_populate() will skip such nodes (and its children) in a similar way to the non-available ones. Cc: devicetree@vger.kernel.org Signed-off-by: Pawel Moll <pawel.moll@arm.com> --- drivers/of/platform.c | 10 ++++++++-- include/linux/of.h | 1 + 2 files changed, 9 insertions(+), 2 deletions(-)