Re: [PATCH 08/14] cxl: Add kernel APIs to get & set the max irqs per context

[Ian Munsie]

Excerpts from Frederic Barrat's message of 2016-07-06 20:11:48 +0200:
> 
> Le 04/07/2016 15:22, Ian Munsie a écrit :
> > From: Ian Munsie 
> >
> > These APIs will be used by the Mellanox CX4 support. While they function
> > standalone to configure existing behaviour, their primary purpose is to
> > allow the Mellanox driver to inform the cxl driver of a hardware
> > limitation, which will be used in a future patch.
> >
> > Signed-off-by: Ian Munsie 
> 
> Any way to add a check that the "set max" API is called before the 
> interrupts are allocated?

I don't think there is any real need - if the set max API has not been
called then we use the maximum number of interrupts possible on the PHB,
which is the correct thing to do if we don't need the workaround. We
could try adding a WARN in the set max API if interrupts have previously
been allocated, but realistically - if a driver developer needs to use
this they already know it and will be testing for it.

Cheers,
-Ian

___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

Re: [PATCH 08/14] cxl: Add kernel APIs to get & set the max irqs per context

[Frederic Barrat]

Le 04/07/2016 15:22, Ian Munsie a écrit :

From: Ian Munsie 

These APIs will be used by the Mellanox CX4 support. While they function
standalone to configure existing behaviour, their primary purpose is to
allow the Mellanox driver to inform the cxl driver of a hardware
limitation, which will be used in a future patch.

Signed-off-by: Ian Munsie 


Any way to add a check that the "set max" API is called before the 
interrupts are allocated?


Reviewed-by: Frederic Barrat 


___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

[PATCH 08/14] cxl: Add kernel APIs to get & set the max irqs per context

[Ian Munsie]

From: Ian Munsie 

These APIs will be used by the Mellanox CX4 support. While they function
standalone to configure existing behaviour, their primary purpose is to
allow the Mellanox driver to inform the cxl driver of a hardware
limitation, which will be used in a future patch.

Signed-off-by: Ian Munsie 
---
 drivers/misc/cxl/api.c | 27 +++
 include/misc/cxl.h | 10 ++
 2 files changed, 37 insertions(+)

diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
index 6a030bf..1e2c0d9 100644
--- a/drivers/misc/cxl/api.c
+++ b/drivers/misc/cxl/api.c
@@ -447,3 +447,30 @@ ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void 
*buf, size_t count)
return cxl_ops->read_adapter_vpd(afu->adapter, buf, count);
 }
 EXPORT_SYMBOL_GPL(cxl_read_adapter_vpd);
+
+int cxl_set_max_irqs_per_process(struct pci_dev *dev, int irqs)
+{
+   struct cxl_afu *afu = cxl_pci_to_afu(dev);
+   if (IS_ERR(afu))
+   return -ENODEV;
+
+   if (irqs > afu->adapter->user_irqs)
+   return -EINVAL;
+
+   /* Limit user_irqs to prevent the user increasing this via sysfs */
+   afu->adapter->user_irqs = irqs;
+   afu->irqs_max = irqs;
+
+   return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_set_max_irqs_per_process);
+
+int cxl_get_max_irqs_per_process(struct pci_dev *dev)
+{
+   struct cxl_afu *afu = cxl_pci_to_afu(dev);
+   if (IS_ERR(afu))
+   return -ENODEV;
+
+   return afu->irqs_max;
+}
+EXPORT_SYMBOL_GPL(cxl_get_max_irqs_per_process);
diff --git a/include/misc/cxl.h b/include/misc/cxl.h
index dd9eebb..fc07ed4 100644
--- a/include/misc/cxl.h
+++ b/include/misc/cxl.h
@@ -166,6 +166,16 @@ void cxl_psa_unmap(void __iomem *addr);
 /*  Get the process element for this context */
 int cxl_process_element(struct cxl_context *ctx);
 
+/*
+ * Limit the number of interrupts that a single context can allocate via
+ * cxl_start_work. If using the api with a real phb, this may be used to
+ * request that additional default contexts be created when allocating
+ * interrupts via pci_enable_msix_range. These will be set to the same running
+ * state as the default context, and if that is running it will reuse the
+ * parameters previously passed to cxl_start_context for the default context.
+ */
+int cxl_set_max_irqs_per_process(struct pci_dev *dev, int irqs);
+int cxl_get_max_irqs_per_process(struct pci_dev *dev);
 
 /*
  * These calls allow drivers to create their own file descriptors and make them
-- 
2.8.1

___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev