On Tue, Sep 17, 2013 at 01:04:06PM +0000, Strashko, Grygorii wrote: > Hi Thierry, > > On 09/16/2013 11:32 AM, Thierry Reding wrote:> Interrupt references are currently resolved very early (when a device is > > created). This has the disadvantage that it will fail in cases where the > > interrupt parent hasn't been probed and no IRQ domain for it has been > > registered yet. To work around that various drivers use explicit > > initcall ordering to force interrupt parents to be probed before devices > > that need them are created. That's error prone and doesn't always work. > > If a platform device uses an interrupt line connected to a different > > platform device (such as a GPIO controller), both will be created in the > > same batch, and the GPIO controller won't have been probed by its driver > > when the depending platform device is created. Interrupt resolution will > > fail in that case. > > > > Another common workaround is for drivers to explicitly resolve interrupt > > references at probe time. This is suboptimal, however, because it will > > require every driver to duplicate the code. > > > > This patch adds support for late interrupt resolution to the platform > > driver core, by resolving the references right before a device driver's > > .probe() function will be called. This not only delays the resolution > > until a much later time (giving interrupt parents a better chance of > > being probed in the meantime), but it also allows the platform driver > > core to queue the device for deferred probing if the interrupt parent > > hasn't registered its IRQ domain yet. > > > > Signed-off-by: Thierry Reding <treding@xxxxxxxxxx> > > --- > > drivers/base/platform.c | 4 ++++ > > drivers/of/platform.c | 43 +++++++++++++++++++++++++++++++++++++------ > > include/linux/of_platform.h | 7 +++++++ > > 3 files changed, 48 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > > index 4f8bef3..8dcf835 100644 > > --- a/drivers/base/platform.c > > +++ b/drivers/base/platform.c > > @@ -481,6 +481,10 @@ static int platform_drv_probe(struct device *_dev) > > Should it be the part of really_probe()? Isn't it? really_probe() takes a struct device and is in fact called by all types of devices. This code, however, is highly platform_device specific, so I don't think we can do it in really_probe(). Unfortunately every device type has its own way of storing interrupts. Platform devices store them as resources, I2C clients store them as a separate field in struct i2c_client, etc. > > +int of_platform_probe(struct platform_device *pdev) > > +{ > > + struct device_node *np = pdev->dev.of_node; > > + int num_irq, ret = 0; > > + > > + if (!pdev->dev.of_node) > > + return 0; > > + > > + num_irq = of_irq_count(pdev->dev.of_node); > > + if (num_irq > 0) { > > + struct resource *res = pdev->resource; > > + int num_reg = pdev->num_resources; > > + int num = num_reg + num_irq; > > + > > + res = krealloc(res, num * sizeof(*res), GFP_KERNEL); > > + if (!res) > > + return -ENOMEM; > > + > > + pdev->num_resources = num; > > + pdev->resource = res; > > + res += num_reg; > > What will happen if Driver probe is failed or deferred? > Seems resource table size will grow each time the Driver probe is > deferred or failed. That's a very good point. I think what we can do is check whether the total number of resources that the device has (pdev->num_resources) corresponds to num_reg + num_irq and skip in that case. That and... > > + ret = of_irq_to_resource_table(np, res, num_irq); > > + if (ret < 0) > > + return ret; ... updating pdev->num_resources after this point should cover all cases. Do you see any other potential problems? Thierry
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