Re: [RFC PATCH v2 05/11] ACPI: platform: setup MSI domain for ACPI based platform device
From: Marc Zyngier
Date: Thu Sep 15 2016 - 11:18:27 EST
On 15/09/16 15:05, Hanjun Guo wrote:
> Hi Marc,
>
> Thanks for your review, reply inline.
>
> On 09/14/2016 11:45 PM, Marc Zyngier wrote:
>> On 14/09/16 15:21, Hanjun Guo wrote:
>>> From: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
>>>
>>> With the platform msi domain created, we can set up the msi domain
>>> for a platform device when it's probed.
>>>
>>> This patch introduces acpi_configure_msi_domain(), which retrieves
>>> the domain from iort and set it to platform device.
>>>
>>> As some platform devices such as an irqchip needs the msi irqdomain
>>> to be the interrupt parent domain, we need to get irqdomain before
>>> platform device is probed.
>>>
>>> Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
>>> Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
>>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>>> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>>> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
>>> Cc: Tomasz Nowicki <tn@xxxxxxxxxxxx>
>>> Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
>>> ---
>>> drivers/acpi/arm64/iort.c | 5 ++++-
>>> drivers/base/platform-msi.c | 15 ++++++++++++++-
>>> drivers/base/platform.c | 2 ++
>>> include/linux/msi.h | 1 +
>>> 4 files changed, 21 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
>>> index 13a1905..bccd3cc 100644
>>> --- a/drivers/acpi/arm64/iort.c
>>> +++ b/drivers/acpi/arm64/iort.c
>>> @@ -478,6 +478,7 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id)
>>> {
>>> struct fwnode_handle *handle;
>>> int its_id;
>>> + enum irq_domain_bus_token bus_token;
>>>
>>> if (iort_dev_find_its_id(dev, req_id, 0, &its_id))
>>> return NULL;
>>> @@ -486,7 +487,9 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id)
>>> if (!handle)
>>> return NULL;
>>>
>>> - return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
>>> + bus_token = dev_is_pci(dev) ?
>>> + DOMAIN_BUS_PCI_MSI : DOMAIN_BUS_PLATFORM_MSI;
>>> + return irq_find_matching_fwnode(handle, bus_token);
>>> }
>>>
>>> static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
>>> diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
>>> index 279e539..f6eae18 100644
>>> --- a/drivers/base/platform-msi.c
>>> +++ b/drivers/base/platform-msi.c
>>> @@ -17,8 +17,8 @@
>>> * along with this program. If not, see <http://www.gnu.org/licenses/>.
>>> */
>>>
>>> +#include <linux/acpi_iort.h>
>>> #include <linux/device.h>
>>> -#include <linux/idr.h>
>>> #include <linux/irq.h>
>>> #include <linux/irqdomain.h>
>>> #include <linux/msi.h>
>>> @@ -416,3 +416,16 @@ int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
>>>
>>> return err;
>>> }
>>> +
>>> +int acpi_configure_msi_domain(struct device *dev)
>>> +{
>>> + struct irq_domain *d = NULL;
>>> +
>>> + d = iort_get_device_domain(dev, 0);
>>
>> This looks completely wrong. Why RID 0? As far as I can see, 0 is not a
>> special value, and could be something else.
>
> You are right. I tried to reuse the API of get irqdomain in IORT for
> PCI devices, but for platform device, we don't have req id in named
> component, so I just pass 0 here, I think I need to prepare another
> API for platform devices.
>
>>
>>> + if (d) {
>>> + dev_set_msi_domain(dev, d);
>>> + return 0;
>>> + }
>>> +
>>> + return -EINVAL;
>>> +}
>>
>> I really hate this, as the platform MSI code is intentionally free of
>> any firmware reference. This should live in the ACPI code.
>
> Will do, I think locate it in iort.c is better.
>
>>
>>> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
>>> index 6482d47..ea01a37 100644
>>> --- a/drivers/base/platform.c
>>> +++ b/drivers/base/platform.c
>>> @@ -24,6 +24,7 @@
>>> #include <linux/pm_domain.h>
>>> #include <linux/idr.h>
>>> #include <linux/acpi.h>
>>> +#include <linux/msi.h>
>>> #include <linux/clk/clk-conf.h>
>>> #include <linux/limits.h>
>>> #include <linux/property.h>
>>> @@ -500,6 +501,7 @@ struct platform_device *platform_device_register_full(
>>> pdev->dev.parent = pdevinfo->parent;
>>> pdev->dev.fwnode = pdevinfo->fwnode;
>>>
>>> + acpi_configure_msi_domain(&pdev->dev);
>>
>> It feels odd to put this in the generic code, while you could perfectly
>> put the call into acpi_platform.c and keep the firmware stuff away from
>> the generic code.
>
> My feeling is the same, I'm still trying to find a new way to do it,
> but I can't simply put that in acpi_platform.c, because
>
> acpi_create_platform_device()
> platform_device_register_full()
> platform_device_alloc() --> dev is alloced
> ...
> dev.fwnode is set
> (I get the msi domain by the fwnode in acpi_configure_msi_domain)
> ...
> platform_device_add() --> which the device is probed.
>
> For devices like irqchip which needs the dev->msi_domain to be
> set before it's really probed, because it needs the msi domain
> to be the parent domain.
>
> If I call the function in acpi_create_platform_device() before
> platform_device_register_full(), we just can't set dev's msi
> domain, but if call it after platform_device_register_full(),
> the irqchip like mbigen will not get its parent domain...
>
> DT is using another API for platform device probe, so has no
> problems like I said above, any suggestions to do it right in
> ACPI?
How about having something that's completely generic and solves
the problem once and for all? Something like this:
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 6482d47..6f0f90b 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -533,6 +533,9 @@ struct platform_device *platform_device_register_full(
goto err;
}
+ if (pdevinfo->pre_add_cb)
+ pdevinfo->pre_add_cb(&pdev->dev);
+
ret = platform_device_add(pdev);
if (ret) {
err:
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index 98c2a7c..44ea133 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -74,6 +74,7 @@ struct platform_device_info {
u64 dma_mask;
struct property_entry *properties;
+ void (*pre_add_cb)(struct device *);
};
extern struct platform_device *platform_device_register_full(
const struct platform_device_info *pdevinfo);
Plug pre_add_cb with your ACPI callback where you can do all the
processing you want before the device is actually added.
Thanks,
M.
--
Jazz is not dead. It just smells funny...