[v2,2/8] PCI: Add registry of MSI chips

This commit adds a very basic registry of msi_chip structures, so that
an IRQ controller driver can register an msi_chip, and a PCIe host
controller can find it, based on a 'struct device_node'.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 drivers/pci/msi.c   | 25 +++++++++++++++++++++++++
 include/linux/msi.h | 11 +++++++++++
 2 files changed, 36 insertions(+)

On Thu, Jun 06, 2013 at 06:41:22PM +0200, Thomas Petazzoni wrote:
[...]
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index 4633529..a1a6084 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -61,6 +61,8 @@ int arch_msi_check_device(struct pci_dev* dev, int nvec, int type);
>  struct msi_chip {
>  	struct module *owner;
>  	struct device *dev;
> +	struct device_node *of_node;

Shouldn't we be reusing the dev.of_node field to look this information
up? On Tegra we do register the MSI chip and set the dev member to the
PCIe host bridge device. Can't the same thing be done for the Armada?

I assume that the MSI controller provider will be instantiated from the
device tree and hence there will already be a struct platform_device and
therefore also a struct device associated with it which should have the
of_node field set to the correct value automatically.

Thierry

On Thu, Jun 06, 2013 at 06:41:22PM +0200, Thomas Petazzoni wrote:
> This commit adds a very basic registry of msi_chip structures, so that
> an IRQ controller driver can register an msi_chip, and a PCIe host
> controller can find it, based on a 'struct device_node'.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> ---
>  drivers/pci/msi.c   | 25 +++++++++++++++++++++++++
>  include/linux/msi.h | 11 +++++++++++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index 4dafac6..0f177ee 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -20,6 +20,7 @@
>  #include <linux/errno.h>
>  #include <linux/io.h>
>  #include <linux/slab.h>
> +#include <linux/of.h>
>  
>  #include "pci.h"
>  
> @@ -70,6 +71,30 @@ int __weak arch_msi_check_device(struct pci_dev *dev, int nvec, int type)
>  # define HAVE_DEFAULT_MSI_SETUP_IRQS
>  #endif
>  
> +#ifdef CONFIG_OF
> +static LIST_HEAD(msi_chip_list);
> +static DEFINE_MUTEX(msi_chip_mutex);
> +
> +void msi_chip_add(struct msi_chip *chip)
> +{
> +	mutex_lock(&msi_chip_mutex);
> +	list_add(&chip->link, &msi_chip_list);
> +	mutex_unlock(&msi_chip_mutex);
> +}
> +
> +struct msi_chip *msi_chip_find_by_of_node(struct device_node *of_node)
> +{
> +	struct msi_chip *c;
> +	list_for_each_entry(c, &msi_chip_list, link) {
> +		if (c->of_node == of_node &&
> +		    of_property_read_bool(c->of_node, "msi-controller"))
> +			return c;
> +	}
> +
> +	return NULL;
> +}
> +#endif

I don't really understand why the msi_chip_list lives here, since
nothing in drivers/pci/msi.c uses it.  Seems like maybe something
that could be in the OF code somewhere?

> +
>  #ifdef HAVE_DEFAULT_MSI_SETUP_IRQS
>  int default_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>  {
> diff --git a/include/linux/msi.h b/include/linux/msi.h
> index 4633529..a1a6084 100644
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -61,6 +61,8 @@ int arch_msi_check_device(struct pci_dev* dev, int nvec, int type);
>  struct msi_chip {
>  	struct module *owner;
>  	struct device *dev;
> +	struct device_node *of_node;
> +	struct list_head link;
>  
>  	int (*setup_irq)(struct msi_chip *chip, struct pci_dev *dev,
>  			 struct msi_desc *desc);
> @@ -69,4 +71,13 @@ struct msi_chip {
>  			    int nvec, int type);
>  };
>  
> +#if defined(CONFIG_PCI_MSI) && defined(CONFIG_OF)
> +void msi_chip_add(struct msi_chip *chip);
> +struct msi_chip *msi_chip_find_by_of_node(struct device_node *of_node);
> +#else
> +static inline void msi_chip_add(struct msi_chip *chip) {}
> +static inline struct msi_chip *
> +msi_chip_find_by_of_node(struct device_node *of_node) { return NULL; }
> +#endif
> +
>  #endif /* LINUX_MSI_H */
> -- 
> 1.8.1.2
> 
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Dear Bjorn Helgaas,

On Tue, 18 Jun 2013 16:48:44 -0600, Bjorn Helgaas wrote:

> I don't really understand why the msi_chip_list lives here, since
> nothing in drivers/pci/msi.c uses it.  Seems like maybe something
> that could be in the OF code somewhere?

Ok, I'll move this to drivers/of/, we'll see what Grant says about
this. Will be part of v3.

Best regards,

Thomas