| Message ID | 1398866717-20268-1-git-send-email-pawel.moll@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Apr 30, 2014 at 9:05 AM, 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. > > Signed-off-by: Pawel Moll <pawel.moll@arm.com> One pondering and one minor change below, otherwise: Acked-by: Rob Herring <robh@kernel.org> > --- > > Changes since v1: > > - added of_node_check_and_set_flag()... (atomic test and set) > - ... used it to atomically mark a node... > - ... clearing the bit on error path. > > drivers/of/platform.c | 18 +++++++++++++----- > include/linux/of.h | 7 +++++++ > 2 files changed, 20 insertions(+), 5 deletions(-) > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 404d1da..b33927a 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -204,12 +204,13 @@ 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_and_set_flag(np, OF_POPULATED)) > return NULL; > > dev = of_device_alloc(np, bus_id, parent); > if (!dev) > - return NULL; > + goto err_clear_flag; I wonder if leaving it set would be the right behavior. I can't see that we would want to process the node again. But this is the exceptional case, so its probably not too important and can stay like this. > > #if defined(CONFIG_MICROBLAZE) > dev->archdata.dma_mask = 0xffffffffUL; > @@ -227,10 +228,14 @@ static struct platform_device *of_platform_device_create_pdata( > > if (of_device_add(dev) != 0) { > platform_device_put(dev); > - return NULL; > + goto err_clear_flag; > } > > return dev; > + > +err_clear_flag: > + of_node_clear_flag(np, OF_POPULATED); > + return NULL; > } > > /** > @@ -262,14 +267,15 @@ 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_and_set_flag(node, OF_POPULATED)) > return NULL; > > dev = amba_device_alloc(NULL, 0, 0); > if (!dev) { > pr_err("%s(): amba_device_alloc() failed for %s\n", > __func__, node->full_name); > - return NULL; > + goto err_clear_flag; > } > > /* setup generic device info */ > @@ -309,6 +315,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node, > > err_free: > amba_device_put(dev); > +err_clear_flag: > + of_node_clear_flag(node, OF_POPULATED); > return NULL; > } > #else /* CONFIG_ARM_AMBA */ > diff --git a/include/linux/of.h b/include/linux/of.h > index 3bad8d1..534cab8 100644 > --- a/include/linux/of.h > +++ b/include/linux/of.h > @@ -130,6 +130,12 @@ static inline int of_node_check_flag(struct device_node *n, unsigned long flag) > return test_bit(flag, &n->_flags); > } > > +static inline int of_node_check_and_set_flag(struct device_node *n, Please keep the well known naming convention of the called function: of_node_test_and_set_flag
On Wed, 30 Apr 2014 10:22:25 -0500, Rob Herring <robherring2@gmail.com> wrote: > On Wed, Apr 30, 2014 at 9:05 AM, 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. > > > > Signed-off-by: Pawel Moll <pawel.moll@arm.com> > > One pondering and one minor change below, otherwise: > > Acked-by: Rob Herring <robh@kernel.org> > > > > --- > > > > Changes since v1: > > > > - added of_node_check_and_set_flag()... (atomic test and set) > > - ... used it to atomically mark a node... > > - ... clearing the bit on error path. > > > > drivers/of/platform.c | 18 +++++++++++++----- > > include/linux/of.h | 7 +++++++ > > 2 files changed, 20 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > > index 404d1da..b33927a 100644 > > --- a/drivers/of/platform.c > > +++ b/drivers/of/platform.c > > @@ -204,12 +204,13 @@ 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_and_set_flag(np, OF_POPULATED)) > > return NULL; > > > > dev = of_device_alloc(np, bus_id, parent); > > if (!dev) > > - return NULL; > > + goto err_clear_flag; > > I wonder if leaving it set would be the right behavior. I can't see > that we would want to process the node again. But this is the > exceptional case, so its probably not too important and can stay like > this. That doesn't work in the case where drivers use of_platform_populate(). MFD devices in particular make use of it. If the driver does not get cleared on removal of the devices, then all MFD users will be broken on driver unbind/rebind. * We really need to have the inverse of of_platform_populate which will remove all child and child's child devices and clear all flags and such. Right now moany drivers are open-coding the removal. * most drivers are somewhat broken on unbind/rebind anyway, but I don't want to make it impossible for a driver to get it right. > > > > > #if defined(CONFIG_MICROBLAZE) > > dev->archdata.dma_mask = 0xffffffffUL; > > @@ -227,10 +228,14 @@ static struct platform_device *of_platform_device_create_pdata( > > > > if (of_device_add(dev) != 0) { > > platform_device_put(dev); > > - return NULL; > > + goto err_clear_flag; > > } > > > > return dev; > > + > > +err_clear_flag: > > + of_node_clear_flag(np, OF_POPULATED); > > + return NULL; > > } > > > > /** > > @@ -262,14 +267,15 @@ 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_and_set_flag(node, OF_POPULATED)) > > return NULL; > > > > dev = amba_device_alloc(NULL, 0, 0); > > if (!dev) { > > pr_err("%s(): amba_device_alloc() failed for %s\n", > > __func__, node->full_name); > > - return NULL; > > + goto err_clear_flag; > > } > > > > /* setup generic device info */ > > @@ -309,6 +315,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node, > > > > err_free: > > amba_device_put(dev); > > +err_clear_flag: > > + of_node_clear_flag(node, OF_POPULATED); > > return NULL; > > } > > #else /* CONFIG_ARM_AMBA */ > > diff --git a/include/linux/of.h b/include/linux/of.h > > index 3bad8d1..534cab8 100644 > > --- a/include/linux/of.h > > +++ b/include/linux/of.h > > @@ -130,6 +130,12 @@ static inline int of_node_check_flag(struct device_node *n, unsigned long flag) > > return test_bit(flag, &n->_flags); > > } > > > > +static inline int of_node_check_and_set_flag(struct device_node *n, > > Please keep the well known naming convention of the called function: > of_node_test_and_set_flag
On Thu, May 1, 2014 at 10:26 AM, Grant Likely <grant.likely@linaro.org> wrote: > On Wed, 30 Apr 2014 10:22:25 -0500, Rob Herring <robherring2@gmail.com> wrote: >> On Wed, Apr 30, 2014 at 9:05 AM, 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. >> > >> > Signed-off-by: Pawel Moll <pawel.moll@arm.com> >> >> One pondering and one minor change below, otherwise: >> >> Acked-by: Rob Herring <robh@kernel.org> >> >> >> > --- >> > >> > Changes since v1: >> > >> > - added of_node_check_and_set_flag()... (atomic test and set) >> > - ... used it to atomically mark a node... >> > - ... clearing the bit on error path. >> > >> > drivers/of/platform.c | 18 +++++++++++++----- >> > include/linux/of.h | 7 +++++++ >> > 2 files changed, 20 insertions(+), 5 deletions(-) >> > >> > diff --git a/drivers/of/platform.c b/drivers/of/platform.c >> > index 404d1da..b33927a 100644 >> > --- a/drivers/of/platform.c >> > +++ b/drivers/of/platform.c >> > @@ -204,12 +204,13 @@ 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_and_set_flag(np, OF_POPULATED)) >> > return NULL; >> > >> > dev = of_device_alloc(np, bus_id, parent); >> > if (!dev) >> > - return NULL; >> > + goto err_clear_flag; >> >> I wonder if leaving it set would be the right behavior. I can't see >> that we would want to process the node again. But this is the >> exceptional case, so its probably not too important and can stay like >> this. > > That doesn't work in the case where drivers use of_platform_populate(). > MFD devices in particular make use of it. If the driver does not get > cleared on removal of the devices, then all MFD users will be broken on > driver unbind/rebind. * > > We really need to have the inverse of of_platform_populate which will > remove all child and child's child devices and clear all flags and such. > Right now moany drivers are open-coding the removal. > > * most drivers are somewhat broken on unbind/rebind anyway, but I don't > want to make it impossible for a driver to get it right. The function shouldn't be too difficult. I would expect it to look something like this. You'll need to check the details. static int __of_platform_unpopulate_device(struct device *dev, void *c) { if (!dev->of_node || !of_node_get_flag(dev->of_node, OF_POPULATED) return 0; // recursively remove the children too --- I'd like to find a way to do this non-recursively device_for_each_child(dev, NULL, __of_platform_unpopulate_device); // Need to check if the device should be explicitly unbound from it's driver before removing it. However, I think the driver core takes care of this for us. // Remove based on the bus type switch (dev->bus) { case &platform_bus_type: platform_device_remove(to_platform_device(dev)); break; case &amba_bus_type: amba_device_remove(to_platform_device(dev)); break; } // Should check here if there are any other children to the device. It is probably bad to remove a device that still has children. Need to check what the driver core will do. } void of_platform_unpopulate(struct device *parent) { device_for_each_child(parent, NULL, __of_platform_unpopulate_device); } > >> >> > >> > #if defined(CONFIG_MICROBLAZE) >> > dev->archdata.dma_mask = 0xffffffffUL; >> > @@ -227,10 +228,14 @@ static struct platform_device *of_platform_device_create_pdata( >> > >> > if (of_device_add(dev) != 0) { >> > platform_device_put(dev); >> > - return NULL; >> > + goto err_clear_flag; >> > } >> > >> > return dev; >> > + >> > +err_clear_flag: >> > + of_node_clear_flag(np, OF_POPULATED); >> > + return NULL; >> > } >> > >> > /** >> > @@ -262,14 +267,15 @@ 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_and_set_flag(node, OF_POPULATED)) >> > return NULL; >> > >> > dev = amba_device_alloc(NULL, 0, 0); >> > if (!dev) { >> > pr_err("%s(): amba_device_alloc() failed for %s\n", >> > __func__, node->full_name); >> > - return NULL; >> > + goto err_clear_flag; >> > } >> > >> > /* setup generic device info */ >> > @@ -309,6 +315,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node, >> > >> > err_free: >> > amba_device_put(dev); >> > +err_clear_flag: >> > + of_node_clear_flag(node, OF_POPULATED); >> > return NULL; >> > } >> > #else /* CONFIG_ARM_AMBA */ >> > diff --git a/include/linux/of.h b/include/linux/of.h >> > index 3bad8d1..534cab8 100644 >> > --- a/include/linux/of.h >> > +++ b/include/linux/of.h >> > @@ -130,6 +130,12 @@ static inline int of_node_check_flag(struct device_node *n, unsigned long flag) >> > return test_bit(flag, &n->_flags); >> > } >> > >> > +static inline int of_node_check_and_set_flag(struct device_node *n, >> >> Please keep the well known naming convention of the called function: >> of_node_test_and_set_flag >
diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 404d1da..b33927a 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -204,12 +204,13 @@ 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_and_set_flag(np, OF_POPULATED)) return NULL; dev = of_device_alloc(np, bus_id, parent); if (!dev) - return NULL; + goto err_clear_flag; #if defined(CONFIG_MICROBLAZE) dev->archdata.dma_mask = 0xffffffffUL; @@ -227,10 +228,14 @@ static struct platform_device *of_platform_device_create_pdata( if (of_device_add(dev) != 0) { platform_device_put(dev); - return NULL; + goto err_clear_flag; } return dev; + +err_clear_flag: + of_node_clear_flag(np, OF_POPULATED); + return NULL; } /** @@ -262,14 +267,15 @@ 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_and_set_flag(node, OF_POPULATED)) return NULL; dev = amba_device_alloc(NULL, 0, 0); if (!dev) { pr_err("%s(): amba_device_alloc() failed for %s\n", __func__, node->full_name); - return NULL; + goto err_clear_flag; } /* setup generic device info */ @@ -309,6 +315,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node, err_free: amba_device_put(dev); +err_clear_flag: + of_node_clear_flag(node, OF_POPULATED); return NULL; } #else /* CONFIG_ARM_AMBA */ diff --git a/include/linux/of.h b/include/linux/of.h index 3bad8d1..534cab8 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -130,6 +130,12 @@ static inline int of_node_check_flag(struct device_node *n, unsigned long flag) return test_bit(flag, &n->_flags); } +static inline int of_node_check_and_set_flag(struct device_node *n, + unsigned long flag) +{ + return test_and_set_bit(flag, &n->_flags); +} + static inline void of_node_set_flag(struct device_node *n, unsigned long flag) { set_bit(flag, &n->_flags); @@ -197,6 +203,7 @@ 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. Signed-off-by: Pawel Moll <pawel.moll@arm.com> --- Changes since v1: - added of_node_check_and_set_flag()... (atomic test and set) - ... used it to atomically mark a node... - ... clearing the bit on error path. drivers/of/platform.c | 18 +++++++++++++----- include/linux/of.h | 7 +++++++ 2 files changed, 20 insertions(+), 5 deletions(-)