| Message ID | 20240627113546.100333-2-mikhail.kshevetskiy@iopsys.eu |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [1/3] fit_dtb: relocate whole fit dtb image instead of selected dtb only | expand |
On 27/06/2024 13:35, Mikhail Kshevetskiy wrote: > Consider a case when we have several similar boards but leds & buttons > connected differently. Some of leds uses gpio, other pwm, third gpio over > spi bitbang. Also different board may have different gpio hogs. And last > but not least: board type stored inside a ubi volume. > > We want a single u-boot image that will support all these boards (we are > not using SPL). So we need runtime dtb switching. > > We can't use MULTI_DTB_FIT and DTB_RESELECT because they tries to switch > dtb too early when flash & ubi drivers are not loaded/activated. > > The following code do runtime switching > > ret = fdtdec_resetup(&rescan); > if (!ret && rescan){ > dm_uninit(); > dm_init_and_scan(false); > } > > but it have several nasty issues > * additional code required to reinitialize console otherwise board will hang. > * MTD subsystem is not cleared, we need to remove mtd partition before > switching to new dtb > * spi-nand flash will be named "spi-nand1" instead of "spi-nand0", thus > flash becomes unusable > * some drivers are unable to deinitialize properly (ex: network driver will > not release mdio interface) > * some memory will leak, because most of drivers assumes that it will never > be unloaded > > To avoid this nasty issues the following hack was implemented > * Full DM and console reinitialization was skipped > * Only missed device/subdevice added from new dtb during device scan. > * Some driver renames their devices. As result we can't use device names > to match old device node with a new one. The special field was added to > struct udevice for this purposes. > * Driver must be binded to the old device one more time to add missed > subdevices. > * uclass must be post_bind to the old device one more time to add missed > subdevices. > * We can't use old dtb anymore, so replace old device node with a new one > for existing devices. > > The following restrictions are present: > * initial dtb MUST be a subset of a new one Surely dtbo is a better application for your usecase? Switching out the entire dtb and "rebooting" the entire driver model seems a bit overkill to add some LEDs? If you can just pick a dtbo at some point, overlay it, maybe re-generate livetree, and then just devices that are affected by the dtbo? Maybe that's a bit of a naive idea... Perhaps it could be restricted to some specific situations, like only support dtbo's that either add new nodes or change just the status property of a node? Though this seems like more or less what you're doing in this patch. > * old devices will NOT be reinitialised > * no devices will be deleted or deactivated > * only new devices will be added > > Typical usage: > ret = fdtdec_resetup(&rescan); > if (!ret && rescan) > dm_rescan(); > > The code was tested with: gpio, gpio_hog, leds, buttons. > > Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu> > --- > drivers/core/device.c | 31 +++++++++++++++++++++++++++++++ > drivers/core/root.c | 15 +++++++++++++++ > dts/Kconfig | 8 ++++++++ > include/dm/device.h | 3 +++ > include/dm/root.h | 23 +++++++++++++++++++++++ > 5 files changed, 80 insertions(+) > > diff --git a/drivers/core/device.c b/drivers/core/device.c > index bf7f261cbce..4f575ca82e7 100644 > --- a/drivers/core/device.c > +++ b/drivers/core/device.c > @@ -62,6 +62,34 @@ static int device_bind_common(struct udevice *parent, const struct driver *drv, > return ret; > } > > +#if CONFIG_IS_ENABLED(MULTI_DTB_FIT_RESCAN) > + if (parent) { > + struct list_head *entry; > + ofnode dev_node; > + > + list_for_each(entry, &parent->child_head) { > + dev = list_entry(entry, struct udevice, sibling_node); > + dev_node = dev_ofnode(dev); > + if ((dev->driver == drv) && (dev->uclass == uc) && > + (dev->driver_data == driver_data) && > + (strcmp(dev->node_name, ofnode_get_name(node)) == 0)) > + { > + ret = 0; > + dev_set_ofnode(dev, node); > + if (drv->bind) > + ret = drv->bind(dev); > + > + if (!ret && uc->uc_drv->post_bind) > + ret = uc->uc_drv->post_bind(dev); > + > + if (!ret && devp) > + *devp = dev; > + return ret; > + } > + } > + } > +#endif > + > dev = calloc(1, sizeof(struct udevice)); > if (!dev) > return -ENOMEM; > @@ -75,6 +103,9 @@ static int device_bind_common(struct udevice *parent, const struct driver *drv, > dev_set_plat(dev, plat); > dev->driver_data = driver_data; > dev->name = name; > +#if CONFIG_IS_ENABLED(MULTI_DTB_FIT_RESCAN) > + dev->node_name = name; > +#endif > dev_set_ofnode(dev, node); > dev->parent = parent; > dev->driver = drv; > diff --git a/drivers/core/root.c b/drivers/core/root.c > index d4ae652bcfb..4bf1ff80636 100644 > --- a/drivers/core/root.c > +++ b/drivers/core/root.c > @@ -340,6 +340,21 @@ static int dm_scan(bool pre_reloc_only) > return dm_probe_devices(gd->dm_root, pre_reloc_only); > } > > +#if CONFIG_IS_ENABLED(MULTI_DTB_FIT_RESCAN) > +int dm_rescan(void) > +{ > + int ret; > + > + ret = dm_extended_scan(false); > + if (ret) { > + debug("dm_extended_scan() failed: %d\n", ret); > + return ret; > + } > + > + return dm_probe_devices(gd->dm_root, false); > +} > +#endif > + > int dm_init_and_scan(bool pre_reloc_only) > { > int ret; > diff --git a/dts/Kconfig b/dts/Kconfig > index 6883a000a05..ab486b21fe2 100644 > --- a/dts/Kconfig > +++ b/dts/Kconfig > @@ -292,6 +292,14 @@ config DTB_RESELECT > config allows boards to implement a function at a later point > during boot to switch to the "correct" dtb. > > +config MULTI_DTB_FIT_RESCAN > + bool "Support switching dtb without drivers unloading (experimental)" > + depends on MULTI_DTB_FIT > + help > + This configs adds possibility to switch from initial (minimal) dtb > + to a "correct" one without devices/drivers unloading (ex: board type > + required to switch dtb stored in ubi volume) > + > config MULTI_DTB_FIT > bool "Support embedding several DTBs in a FIT image for u-boot" > help > diff --git a/include/dm/device.h b/include/dm/device.h > index add67f9ec06..409b1c4861a 100644 > --- a/include/dm/device.h > +++ b/include/dm/device.h > @@ -170,6 +170,9 @@ enum { > struct udevice { > const struct driver *driver; > const char *name; > +#if CONFIG_IS_ENABLED(MULTI_DTB_FIT_RESCAN) > + const char *node_name; > +#endif > void *plat_; > void *parent_plat_; > void *uclass_plat_; > diff --git a/include/dm/root.h b/include/dm/root.h > index b2f30a842f5..dcab28f6c47 100644 > --- a/include/dm/root.h > +++ b/include/dm/root.h > @@ -155,6 +155,29 @@ int dm_init(bool of_live); > */ > int dm_uninit(void); > > +#if CONFIG_IS_ENABLED(MULTI_DTB_FIT_RESCAN) > +/** > + * dm_rescan - Rescan ftd and add missed DM devices (experimental) > + * > + * This function can be used for switching from initial (minimal) dtb > + * to a "correct" one without devices/drivers unloading. > + * > + * Restrictions: > + * - initial dtb MUST be a subset of a new one > + * - old devices will NOT be reinitialised > + * - no devices will be deleted or deactivated > + * - only new devices will be added > + * > + * Typical usage: > + * ret = fdtdec_resetup(&rescan); > + * if (!ret && rescan) > + * dm_rescan(); > + * > + * Return: 0 if OK, -ve on error > + */ > +int dm_rescan(void); > +#endif > + > #if CONFIG_IS_ENABLED(DM_DEVICE_REMOVE) > /** > * dm_remove_devices_flags - Call remove function of all drivers with
diff --git a/drivers/core/device.c b/drivers/core/device.c index bf7f261cbce..4f575ca82e7 100644 --- a/drivers/core/device.c +++ b/drivers/core/device.c @@ -62,6 +62,34 @@ static int device_bind_common(struct udevice *parent, const struct driver *drv, return ret; } +#if CONFIG_IS_ENABLED(MULTI_DTB_FIT_RESCAN) + if (parent) { + struct list_head *entry; + ofnode dev_node; + + list_for_each(entry, &parent->child_head) { + dev = list_entry(entry, struct udevice, sibling_node); + dev_node = dev_ofnode(dev); + if ((dev->driver == drv) && (dev->uclass == uc) && + (dev->driver_data == driver_data) && + (strcmp(dev->node_name, ofnode_get_name(node)) == 0)) + { + ret = 0; + dev_set_ofnode(dev, node); + if (drv->bind) + ret = drv->bind(dev); + + if (!ret && uc->uc_drv->post_bind) + ret = uc->uc_drv->post_bind(dev); + + if (!ret && devp) + *devp = dev; + return ret; + } + } + } +#endif + dev = calloc(1, sizeof(struct udevice)); if (!dev) return -ENOMEM; @@ -75,6 +103,9 @@ static int device_bind_common(struct udevice *parent, const struct driver *drv, dev_set_plat(dev, plat); dev->driver_data = driver_data; dev->name = name; +#if CONFIG_IS_ENABLED(MULTI_DTB_FIT_RESCAN) + dev->node_name = name; +#endif dev_set_ofnode(dev, node); dev->parent = parent; dev->driver = drv; diff --git a/drivers/core/root.c b/drivers/core/root.c index d4ae652bcfb..4bf1ff80636 100644 --- a/drivers/core/root.c +++ b/drivers/core/root.c @@ -340,6 +340,21 @@ static int dm_scan(bool pre_reloc_only) return dm_probe_devices(gd->dm_root, pre_reloc_only); } +#if CONFIG_IS_ENABLED(MULTI_DTB_FIT_RESCAN) +int dm_rescan(void) +{ + int ret; + + ret = dm_extended_scan(false); + if (ret) { + debug("dm_extended_scan() failed: %d\n", ret); + return ret; + } + + return dm_probe_devices(gd->dm_root, false); +} +#endif + int dm_init_and_scan(bool pre_reloc_only) { int ret; diff --git a/dts/Kconfig b/dts/Kconfig index 6883a000a05..ab486b21fe2 100644 --- a/dts/Kconfig +++ b/dts/Kconfig @@ -292,6 +292,14 @@ config DTB_RESELECT config allows boards to implement a function at a later point during boot to switch to the "correct" dtb. +config MULTI_DTB_FIT_RESCAN + bool "Support switching dtb without drivers unloading (experimental)" + depends on MULTI_DTB_FIT + help + This configs adds possibility to switch from initial (minimal) dtb + to a "correct" one without devices/drivers unloading (ex: board type + required to switch dtb stored in ubi volume) + config MULTI_DTB_FIT bool "Support embedding several DTBs in a FIT image for u-boot" help diff --git a/include/dm/device.h b/include/dm/device.h index add67f9ec06..409b1c4861a 100644 --- a/include/dm/device.h +++ b/include/dm/device.h @@ -170,6 +170,9 @@ enum { struct udevice { const struct driver *driver; const char *name; +#if CONFIG_IS_ENABLED(MULTI_DTB_FIT_RESCAN) + const char *node_name; +#endif void *plat_; void *parent_plat_; void *uclass_plat_; diff --git a/include/dm/root.h b/include/dm/root.h index b2f30a842f5..dcab28f6c47 100644 --- a/include/dm/root.h +++ b/include/dm/root.h @@ -155,6 +155,29 @@ int dm_init(bool of_live); */ int dm_uninit(void); +#if CONFIG_IS_ENABLED(MULTI_DTB_FIT_RESCAN) +/** + * dm_rescan - Rescan ftd and add missed DM devices (experimental) + * + * This function can be used for switching from initial (minimal) dtb + * to a "correct" one without devices/drivers unloading. + * + * Restrictions: + * - initial dtb MUST be a subset of a new one + * - old devices will NOT be reinitialised + * - no devices will be deleted or deactivated + * - only new devices will be added + * + * Typical usage: + * ret = fdtdec_resetup(&rescan); + * if (!ret && rescan) + * dm_rescan(); + * + * Return: 0 if OK, -ve on error + */ +int dm_rescan(void); +#endif + #if CONFIG_IS_ENABLED(DM_DEVICE_REMOVE) /** * dm_remove_devices_flags - Call remove function of all drivers with
Consider a case when we have several similar boards but leds & buttons connected differently. Some of leds uses gpio, other pwm, third gpio over spi bitbang. Also different board may have different gpio hogs. And last but not least: board type stored inside a ubi volume. We want a single u-boot image that will support all these boards (we are not using SPL). So we need runtime dtb switching. We can't use MULTI_DTB_FIT and DTB_RESELECT because they tries to switch dtb too early when flash & ubi drivers are not loaded/activated. The following code do runtime switching ret = fdtdec_resetup(&rescan); if (!ret && rescan){ dm_uninit(); dm_init_and_scan(false); } but it have several nasty issues * additional code required to reinitialize console otherwise board will hang. * MTD subsystem is not cleared, we need to remove mtd partition before switching to new dtb * spi-nand flash will be named "spi-nand1" instead of "spi-nand0", thus flash becomes unusable * some drivers are unable to deinitialize properly (ex: network driver will not release mdio interface) * some memory will leak, because most of drivers assumes that it will never be unloaded To avoid this nasty issues the following hack was implemented * Full DM and console reinitialization was skipped * Only missed device/subdevice added from new dtb during device scan. * Some driver renames their devices. As result we can't use device names to match old device node with a new one. The special field was added to struct udevice for this purposes. * Driver must be binded to the old device one more time to add missed subdevices. * uclass must be post_bind to the old device one more time to add missed subdevices. * We can't use old dtb anymore, so replace old device node with a new one for existing devices. The following restrictions are present: * initial dtb MUST be a subset of a new one * old devices will NOT be reinitialised * no devices will be deleted or deactivated * only new devices will be added Typical usage: ret = fdtdec_resetup(&rescan); if (!ret && rescan) dm_rescan(); The code was tested with: gpio, gpio_hog, leds, buttons. Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu> --- drivers/core/device.c | 31 +++++++++++++++++++++++++++++++ drivers/core/root.c | 15 +++++++++++++++ dts/Kconfig | 8 ++++++++ include/dm/device.h | 3 +++ include/dm/root.h | 23 +++++++++++++++++++++++ 5 files changed, 80 insertions(+)