[PATCH 2/4] fsl_msi: enable msi allocation in all banks

[Li Yang]

From: Zhao Chenhui 

Put all fsl_msi banks in a linked list. The list of banks then can be
traversed when allocating new msi interrupts.

Signed-off-by: Zhao Chenhui 
Signed-off-by: Li Yang 
---
 arch/powerpc/sysdev/fsl_msi.c |   29 ++---
 arch/powerpc/sysdev/fsl_msi.h |2 ++
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/sysdev/fsl_msi.c b/arch/powerpc/sysdev/fsl_msi.c
index 716862f..c46db75 100644
--- a/arch/powerpc/sysdev/fsl_msi.c
+++ b/arch/powerpc/sysdev/fsl_msi.c
@@ -24,6 +24,8 @@
 #include 
 #include "fsl_msi.h"
 
+LIST_HEAD(msi_head);
+
 struct fsl_msi_feature {
u32 fsl_pic_ip;
u32 msiir_offset;
@@ -143,15 +145,26 @@ static int fsl_setup_msi_irqs(struct pci_dev *pdev, int 
nvec, int type)
struct msi_msg msg;
struct fsl_msi *msi_data;
 
+   if (list_empty(&msi_head)) {
+   pr_debug("%s: msi init error\n", __func__);
+   rc = -EFAULT;
+   goto out_free;
+   }
+
list_for_each_entry(entry, &pdev->msi_list, list) {
-   msi_data = get_irq_chip_data(entry->irq);
 
-   hwirq = msi_bitmap_alloc_hwirqs(&msi_data->bitmap, 1);
-   if (hwirq < 0) {
-   rc = hwirq;
-   pr_debug("%s: fail allocating msi interrupt\n",
-   __func__);
-   goto out_free;
+   list_for_each_entry(msi_data, &msi_head, list) {
+
+   hwirq = msi_bitmap_alloc_hwirqs(&msi_data->bitmap, 1);
+   if (hwirq >= 0)
+   break;
+
+   if (list_is_last(&msi_data->list, &msi_head)) {
+   rc = hwirq;
+   pr_debug("%s: fail allocating msi interrupt\n",
+   __func__);
+   goto out_free;
+   }
}
 
virq = irq_create_mapping(msi_data->irqhost, hwirq);
@@ -335,6 +348,8 @@ static int __devinit fsl_of_msi_probe(struct of_device *dev,
}
}
 
+   list_add_tail(&msi->list, &msi_head);
+
/* The multiple setting ppc_md.setup_msi_irqs will not harm things */
if (!ppc_md.setup_msi_irqs) {
ppc_md.setup_msi_irqs = fsl_setup_msi_irqs;
diff --git a/arch/powerpc/sysdev/fsl_msi.h b/arch/powerpc/sysdev/fsl_msi.h
index 331c7e7..8fc5523 100644
--- a/arch/powerpc/sysdev/fsl_msi.h
+++ b/arch/powerpc/sysdev/fsl_msi.h
@@ -34,6 +34,8 @@ struct fsl_msi {
u32 feature;
 
struct msi_bitmap bitmap;
+
+   struct list_head list;  /* support multiple MSI banks */
 };
 
 #endif /* _POWERPC_SYSDEV_FSL_MSI_H */
-- 
1.6.6-rc1.GIT

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Re: [PATCH 2/4] fsl_msi: enable msi allocation in all banks

[Michael Ellerman]

On Fri, 2010-04-16 at 15:34 +0800, Li Yang wrote:
> From: Zhao Chenhui 
> 
> Put all fsl_msi banks in a linked list. The list of banks then can be
> traversed when allocating new msi interrupts.

So there are multiple banks, and you just use the first one that has an
empty slot in it's bitmap?

> Signed-off-by: Zhao Chenhui 
> Signed-off-by: Li Yang 
> ---
>  arch/powerpc/sysdev/fsl_msi.c |   29 ++---
>  arch/powerpc/sysdev/fsl_msi.h |2 ++
>  2 files changed, 24 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/powerpc/sysdev/fsl_msi.c b/arch/powerpc/sysdev/fsl_msi.c
> index 716862f..c46db75 100644
> --- a/arch/powerpc/sysdev/fsl_msi.c
> +++ b/arch/powerpc/sysdev/fsl_msi.c
> @@ -24,6 +24,8 @@
>  #include 
>  #include "fsl_msi.h"
>  
> +LIST_HEAD(msi_head);
> +
>  struct fsl_msi_feature {
>   u32 fsl_pic_ip;
>   u32 msiir_offset;
> @@ -143,15 +145,26 @@ static int fsl_setup_msi_irqs(struct pci_dev *pdev, int 
> nvec, int type)
>   struct msi_msg msg;
>   struct fsl_msi *msi_data;
>  
> + if (list_empty(&msi_head)) {
> + pr_debug("%s: msi init error\n", __func__);
> + rc = -EFAULT;
> + goto out_free;
> + }

If there's an error probing then fsl_setup_msi_irqs() should not be
installed as ppc_md.setup_msi_irqs(), and this code should never run.
ie. You shouldn't need this check.

> +
>   list_for_each_entry(entry, &pdev->msi_list, list) {
> - msi_data = get_irq_chip_data(entry->irq);
>  
> - hwirq = msi_bitmap_alloc_hwirqs(&msi_data->bitmap, 1);
> - if (hwirq < 0) {
> - rc = hwirq;
> - pr_debug("%s: fail allocating msi interrupt\n",
> - __func__);
> - goto out_free;
> + list_for_each_entry(msi_data, &msi_head, list) {
> +
> + hwirq = msi_bitmap_alloc_hwirqs(&msi_data->bitmap, 1);
> + if (hwirq >= 0)
> + break;
> +
> + if (list_is_last(&msi_data->list, &msi_head)) {
> + rc = hwirq;
> + pr_debug("%s: fail allocating msi interrupt\n",
> + __func__);
> + goto out_free;
> + }

You could make this cleaner by pulling the inner loop into a separate
function, and when you fall off the end of the list you return < 0. That
would avoid needing the list_is_last() check.

cheers


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Re: [PATCH 2/4] fsl_msi: enable msi allocation in all banks

[Li Yang]

On Mon, Apr 19, 2010 at 10:46 AM, Michael Ellerman
 wrote:
> On Fri, 2010-04-16 at 15:34 +0800, Li Yang wrote:
>> From: Zhao Chenhui 
>>
>> Put all fsl_msi banks in a linked list. The list of banks then can be
>> traversed when allocating new msi interrupts.
>
> So there are multiple banks, and you just use the first one that has an
> empty slot in it's bitmap?

Yes, currently we are.  What allocation algorithm do you think is
better?  I don't think spreading the allocation evenly should have any
performance benefit.  The point of multiple banks should be better
insulation through multiple OS's, IMHO.

- Leo
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