Patchwork powerpc/pci-hotplug: fix the rescanned pci device's dma_set_mask issue

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Submitter Yuanquan Chen
Date Nov. 28, 2012, 2:34 a.m.
Message ID <50B5782A.4050308@freescale.com>
Download mbox | patch
Permalink /patch/202359/
State Rejected
Headers show

Comments

Yuanquan Chen - Nov. 28, 2012, 2:34 a.m.
On 11/25/2012 08:41 PM, Kumar Gala wrote:
> On Nov 22, 2012, at 10:29 PM, Yuanquan Chen wrote:
>
>> On powerpc arch, dma_ops of rescanned pci device after system's booting up won't be
>> initialized by system, so it will fail to execute the dma_set_mask in the device's
>> driver. Initialize it to solve this issue.
>>
>> Signed-off-by: Yuanquan Chen <B41889@freescale.com>
>> ---
>> arch/powerpc/include/asm/dma-mapping.h |    7 +++++--
>> 1 file changed, 5 insertions(+), 2 deletions(-)
> This is not the right way to get the dma_ops setup.  You need to find some other point for the hotplug scenario to get the dma_ops setup.
>
> - k

Hi Kumar,

I read the code about pci bus scan and rescan. Only the 
pcibios_fixup_bus in pci_scan_child_bus and
pcibios_enable_device in pci_rescan_bus are arch related code. The 
pcibios_fixup_bus won't be called
for the rescanned PCI devices due to the bus->is_added has been set for 
the first scanning at boot time.
So I think it's more reasonable to do the same work as pcibios_fixup_bus 
for rescanned PCI device in
pcibios_enable_device. The patch code is a copy of 
pcibios_setup_bus_devices called by pcibios_fixup_bus,
It can solve the dma_set_mask and irq related issues of rescanned PCI 
device on powerpc arch. What's
your opinion?

Thanks,
yuanquan


>> diff --git a/arch/powerpc/include/asm/dma-mapping.h b/arch/powerpc/include/asm/dma-mapping.h
>> index 7816087..22eae53 100644
>> --- a/arch/powerpc/include/asm/dma-mapping.h
>> +++ b/arch/powerpc/include/asm/dma-mapping.h
>> @@ -126,8 +126,11 @@ static inline int dma_supported(struct device *dev, u64 mask)
>> {
>> 	struct dma_map_ops *dma_ops = get_dma_ops(dev);
>>
>> -	if (unlikely(dma_ops == NULL))
>> -		return 0;
>> +	if (unlikely(dma_ops == NULL)) {
>> +		set_dma_ops(dev, &dma_direct_ops);
>> +		set_dma_offset(dev, PCI_DRAM_OFFSET);
>> +		dma_ops = &dma_direct_ops;
>> +	}
>> 	if (dma_ops->dma_supported == NULL)
>> 		return 1;
>> 	return dma_ops->dma_supported(dev, mask);
>> -- 
>> 1.7.9.5
>>
>>
>> _______________________________________________
>> Linuxppc-dev mailing list
>> Linuxppc-dev@lists.ozlabs.org
>> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
>
>
Kumar Gala - Nov. 28, 2012, 5:34 p.m.
On Nov 27, 2012, at 8:34 PM, Chen Yuanquan-B41889 wrote:

> On 11/25/2012 08:41 PM, Kumar Gala wrote:
>> On Nov 22, 2012, at 10:29 PM, Yuanquan Chen wrote:
>> 
>>> On powerpc arch, dma_ops of rescanned pci device after system's booting up won't be
>>> initialized by system, so it will fail to execute the dma_set_mask in the device's
>>> driver. Initialize it to solve this issue.
>>> 
>>> Signed-off-by: Yuanquan Chen <B41889@freescale.com>
>>> ---
>>> arch/powerpc/include/asm/dma-mapping.h |    7 +++++--
>>> 1 file changed, 5 insertions(+), 2 deletions(-)
>> This is not the right way to get the dma_ops setup.  You need to find some other point for the hotplug scenario to get the dma_ops setup.
>> 
>> - k
> 
> Hi Kumar,
> 
> I read the code about pci bus scan and rescan. Only the pcibios_fixup_bus in pci_scan_child_bus and
> pcibios_enable_device in pci_rescan_bus are arch related code. The pcibios_fixup_bus won't be called
> for the rescanned PCI devices due to the bus->is_added has been set for the first scanning at boot time.
> So I think it's more reasonable to do the same work as pcibios_fixup_bus for rescanned PCI device in
> pcibios_enable_device. The patch code is a copy of pcibios_setup_bus_devices called by pcibios_fixup_bus,
> It can solve the dma_set_mask and irq related issues of rescanned PCI device on powerpc arch. What's
> your opinion?
> 
> Thanks,
> yuanquan
> 
> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
> index 7f94f76..30f7d61 100644
> --- a/arch/powerpc/kernel/pci-common.c
> +++ b/arch/powerpc/kernel/pci-common.c
> @@ -1496,6 +1496,23 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
>                if (ppc_md.pcibios_enable_device_hook(dev))
>                        return -EINVAL;
> 
> +       if (!dev->is_added) {
> +               set_dev_node(&dev->dev, pcibus_to_node(dev->bus));
> +
> +               /* Hook up default DMA ops */
> +               set_dma_ops(&dev->dev, pci_dma_ops);
> +               set_dma_offset(&dev->dev, PCI_DRAM_OFFSET);
> +
> +               /* Additional platform DMA/iommu setup */
> +               if (ppc_md.pci_dma_dev_setup)
> +                       ppc_md.pci_dma_dev_setup(dev);
> +
> +               /* Read default IRQs and fixup if necessary */
> +               pci_read_irq_line(dev);
> +               if (ppc_md.pci_irq_fixup)
> +                       ppc_md.pci_irq_fixup(dev);
> +       }
> +
>        return pci_enable_resources(dev, mask);
> }
> 

This looks better than the first patch..  I'm surprised that the IBM guys don't run into a similar issue with their hotplug support.

Maybe Ben or someone else will comment.

- k

>>> diff --git a/arch/powerpc/include/asm/dma-mapping.h b/arch/powerpc/include/asm/dma-mapping.h
>>> index 7816087..22eae53 100644
>>> --- a/arch/powerpc/include/asm/dma-mapping.h
>>> +++ b/arch/powerpc/include/asm/dma-mapping.h
>>> @@ -126,8 +126,11 @@ static inline int dma_supported(struct device *dev, u64 mask)
>>> {
>>> 	struct dma_map_ops *dma_ops = get_dma_ops(dev);
>>> 
>>> -	if (unlikely(dma_ops == NULL))
>>> -		return 0;
>>> +	if (unlikely(dma_ops == NULL)) {
>>> +		set_dma_ops(dev, &dma_direct_ops);
>>> +		set_dma_offset(dev, PCI_DRAM_OFFSET);
>>> +		dma_ops = &dma_direct_ops;
>>> +	}
>>> 	if (dma_ops->dma_supported == NULL)
>>> 		return 1;
>>> 	return dma_ops->dma_supported(dev, mask);
>>> -- 
>>> 1.7.9.5
>>> 
>>> 
>>> _______________________________________________
>>> Linuxppc-dev mailing list
>>> Linuxppc-dev@lists.ozlabs.org
>>> https://lists.ozlabs.org/listinfo/linuxppc-dev
>> 
>> 
>> 
>
Kumar Gala - Dec. 4, 2012, 2:32 p.m.
On Nov 28, 2012, at 11:34 AM, Kumar Gala wrote:

> 
> On Nov 27, 2012, at 8:34 PM, Chen Yuanquan-B41889 wrote:
> 
>> On 11/25/2012 08:41 PM, Kumar Gala wrote:
>>> On Nov 22, 2012, at 10:29 PM, Yuanquan Chen wrote:
>>> 
>>>> On powerpc arch, dma_ops of rescanned pci device after system's booting up won't be
>>>> initialized by system, so it will fail to execute the dma_set_mask in the device's
>>>> driver. Initialize it to solve this issue.
>>>> 
>>>> Signed-off-by: Yuanquan Chen <B41889@freescale.com>
>>>> ---
>>>> arch/powerpc/include/asm/dma-mapping.h |    7 +++++--
>>>> 1 file changed, 5 insertions(+), 2 deletions(-)
>>> This is not the right way to get the dma_ops setup.  You need to find some other point for the hotplug scenario to get the dma_ops setup.
>>> 
>>> - k
>> 
>> Hi Kumar,
>> 
>> I read the code about pci bus scan and rescan. Only the pcibios_fixup_bus in pci_scan_child_bus and
>> pcibios_enable_device in pci_rescan_bus are arch related code. The pcibios_fixup_bus won't be called
>> for the rescanned PCI devices due to the bus->is_added has been set for the first scanning at boot time.
>> So I think it's more reasonable to do the same work as pcibios_fixup_bus for rescanned PCI device in
>> pcibios_enable_device. The patch code is a copy of pcibios_setup_bus_devices called by pcibios_fixup_bus,
>> It can solve the dma_set_mask and irq related issues of rescanned PCI device on powerpc arch. What's
>> your opinion?
>> 
>> Thanks,
>> yuanquan
>> 
>> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
>> index 7f94f76..30f7d61 100644
>> --- a/arch/powerpc/kernel/pci-common.c
>> +++ b/arch/powerpc/kernel/pci-common.c
>> @@ -1496,6 +1496,23 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
>>               if (ppc_md.pcibios_enable_device_hook(dev))
>>                       return -EINVAL;
>> 
>> +       if (!dev->is_added) {
>> +               set_dev_node(&dev->dev, pcibus_to_node(dev->bus));
>> +
>> +               /* Hook up default DMA ops */
>> +               set_dma_ops(&dev->dev, pci_dma_ops);
>> +               set_dma_offset(&dev->dev, PCI_DRAM_OFFSET);
>> +
>> +               /* Additional platform DMA/iommu setup */
>> +               if (ppc_md.pci_dma_dev_setup)
>> +                       ppc_md.pci_dma_dev_setup(dev);
>> +
>> +               /* Read default IRQs and fixup if necessary */
>> +               pci_read_irq_line(dev);
>> +               if (ppc_md.pci_irq_fixup)
>> +                       ppc_md.pci_irq_fixup(dev);
>> +       }
>> +
>>       return pci_enable_resources(dev, mask);
>> }
>> 
> 
> This looks better than the first patch..  I'm surprised that the IBM guys don't run into a similar issue with their hotplug support.
> 
> Maybe Ben or someone else will comment.
> 
> - k

How about you post this as a clean patch, will be easier to get Ben to comment on that.

- k

Patch

diff --git a/arch/powerpc/kernel/pci-common.c 
b/arch/powerpc/kernel/pci-common.c
index 7f94f76..30f7d61 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1496,6 +1496,23 @@  int pcibios_enable_device(struct pci_dev *dev, 
int mask)
                 if (ppc_md.pcibios_enable_device_hook(dev))
                         return -EINVAL;

+       if (!dev->is_added) {
+               set_dev_node(&dev->dev, pcibus_to_node(dev->bus));
+
+               /* Hook up default DMA ops */
+               set_dma_ops(&dev->dev, pci_dma_ops);
+               set_dma_offset(&dev->dev, PCI_DRAM_OFFSET);
+
+               /* Additional platform DMA/iommu setup */
+               if (ppc_md.pci_dma_dev_setup)
+                       ppc_md.pci_dma_dev_setup(dev);
+
+               /* Read default IRQs and fixup if necessary */
+               pci_read_irq_line(dev);
+               if (ppc_md.pci_irq_fixup)
+                       ppc_md.pci_irq_fixup(dev);
+       }
+
         return pci_enable_resources(dev, mask);
  }