On Fri, Feb 21, 2014 at 02:18:40PM +0100, Jean-Jacques Hiblot wrote: > The goal of this patch is to allow drivers to be probed even if at the time of > the DT parsing some of their ressources are not available yet. > > In the current situation, the resource of a platform device are filled from > the > DT at the time the device is created (of_device_alloc()). The drawbackof this > is that a device sitting close to the top of the DT (ahb for example) but > depending on ressources that are initialized later (IRQ domain dynamically > created for example) will fail to probe because the ressources don't exist > at this time. > > This patch fills the resource structure only before the device is probed and > will defer the probe if the resource are not available yet. > > Signed-off-by: Jean-Jacques Hiblot <[email protected]> > Reviewed-by: Gregory CLEMENT <[email protected]>
Tested-by: Ludovic Desroches <[email protected]> I wanted to add support for the external ethernet controller on at91sam9n12ek board and I was facing an issue because the irq domain doesn't exist yet (gpio controller as parent interrupt). This patch solves this trouble. > --- > > Hi Grant, > > I reworked the patch as you proposed. To keep the overhead minimum, nirq and > nreg are computed only the first time. > In this implementation, only the missing IRQ ressources are re-tried for. It > could > easily be changed to re-parse all the IRQs though (replace if (!res->flags) > with if ((!res->flags) || (res->flags & IORESOURCE_IRQ)). > > drivers/base/platform.c | 5 +++ > drivers/of/platform.c | 100 > +++++++++++++++++++++++++++++++++----------- > include/linux/of_platform.h | 10 +++++ > 3 files changed, 90 insertions(+), 25 deletions(-) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index bc78848..cee9b8d 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -481,6 +481,10 @@ static int platform_drv_probe(struct device *_dev) > struct platform_device *dev = to_platform_device(_dev); > int ret; > > + ret = of_platform_device_prepare(dev); > + if (ret) > + goto error; > + > if (ACPI_HANDLE(_dev)) > acpi_dev_pm_attach(_dev, true); > > @@ -488,6 +492,7 @@ static int platform_drv_probe(struct device *_dev) > if (ret && ACPI_HANDLE(_dev)) > acpi_dev_pm_detach(_dev, true); > > +error: > if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) { > dev_warn(_dev, "probe deferral not supported\n"); > ret = -ENXIO; > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 404d1da..a4e2602 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -141,36 +141,11 @@ struct platform_device *of_device_alloc(struct > device_node *np, > struct device *parent) > { > struct platform_device *dev; > - int rc, i, num_reg = 0, num_irq; > - struct resource *res, temp_res; > > dev = platform_device_alloc("", -1); > if (!dev) > return NULL; > > - /* count the io and irq resources */ > - if (of_can_translate_address(np)) > - while (of_address_to_resource(np, num_reg, &temp_res) == 0) > - num_reg++; > - num_irq = of_irq_count(np); > - > - /* Populate the resource table */ > - if (num_irq || num_reg) { > - res = kzalloc(sizeof(*res) * (num_irq + num_reg), GFP_KERNEL); > - if (!res) { > - platform_device_put(dev); > - return NULL; > - } > - > - dev->num_resources = num_reg + num_irq; > - dev->resource = res; > - for (i = 0; i < num_reg; i++, res++) { > - rc = of_address_to_resource(np, i, res); > - WARN_ON(rc); > - } > - WARN_ON(of_irq_to_resource_table(np, res, num_irq) != num_irq); > - } > - > dev->dev.of_node = of_node_get(np); > #if defined(CONFIG_MICROBLAZE) > dev->dev.dma_mask = &dev->archdata.dma_mask; > @@ -233,6 +208,81 @@ static struct platform_device > *of_platform_device_create_pdata( > return dev; > } > > +static int of_reg_count(struct device_node *np) > +{ > + int nreg = 0; > + if (of_can_translate_address(np)) { > + struct resource temp_res; > + while (of_address_to_resource(np, nreg, &temp_res) == 0) > + nreg++; > + } > + return nreg; > +} > + > +int of_platform_device_prepare(struct platform_device *dev) > +{ > + struct device_node *np; > + int i, irq_index; > + struct resource *res; > + > + /* > + * This function applies only devices described in the DT. > + * Other platform devices have their ressources already populated. > + */ > + np = dev->dev.of_node; > + if (!np) > + return 0; > + > + /* Populate the resource table */ > + if (!dev->resource) { > + int rc, nreg = 0, nirq; > + /* count the io and irq resources */ > + nreg = of_reg_count(np); > + nirq = of_irq_count(np); > + > + if (!nirq && !nreg) > + return 0; > + > + res = kzalloc(sizeof(*res) * (nirq + nreg), GFP_KERNEL); > + if (!res) > + return -ENOMEM; > + > + dev->resource = res; > + dev->num_resources = nreg + nirq; > + > + for (i = 0; i < nreg; i++, res++) { > + rc = of_address_to_resource(np, i, res); > + if (WARN_ON(rc)) { > + /* THIS IS BAD; don't try to defer probing */ > + dev->num_resources = 0; > + dev->resource = NULL; > + kfree(res); > + return rc; > + } > + } > + > + if (!rc && of_irq_to_resource_table(np, res, nirq) != nirq) { > + /* IRQ controller is yet available. defer probing */ > + return -EPROBE_DEFER; > + } > + > + return 0; > + } > + > + /* See which IRQ resources need to be redone */ > + irq_index = 0; > + for (i = 0, res = dev->resource; i < dev->num_resources; i++, res++) { > + if (!res->flags) { > + if (!of_irq_to_resource(np, irq_index, res)) > + return -EPROBE_DEFER; > + irq_index++; > + } else if (res->flags & IORESOURCE_IRQ) > + irq_index++; > + } > + return 0; > +} > +EXPORT_SYMBOL(of_platform_device_prepare); > + > /** > * of_platform_device_create - Alloc, initialize and register an of_device > * @np: pointer to node to create device for > diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h > index 05cb4a9..4e487ff 100644 > --- a/include/linux/of_platform.h > +++ b/include/linux/of_platform.h > @@ -53,6 +53,16 @@ struct of_dev_auxdata { > > extern const struct of_device_id of_default_bus_match_table[]; > > +/* Populate the resource for a platform device */ > +#ifdef CONFIG_OF > +int of_platform_device_prepare(struct platform_device *dev); > +#else > +static inline int of_platform_device_prepare( > + struct platform_device *dev) > +{ > + return 0; > +} > +#endif > /* Platform drivers register/unregister */ > extern struct platform_device *of_device_alloc(struct device_node *np, > const char *bus_id, > -- > 1.9.0 > > > _______________________________________________ > linux-arm-kernel mailing list > [email protected] > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
