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

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Submitter Yang Li
Date April 16, 2010, 7:34 a.m.
Message ID <1271403278-30091-2-git-send-email-leoli@freescale.com>
Download mbox | patch
Permalink /patch/50312/
State Superseded
Delegated to: Kumar Gala
Headers show

Comments

Yang Li - April 16, 2010, 7:34 a.m.
From: Zhao Chenhui <b26998@freescale.com>

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 <b26998@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
---
 arch/powerpc/sysdev/fsl_msi.c |   29 ++++++++++++++++++++++-------
 arch/powerpc/sysdev/fsl_msi.h |    2 ++
 2 files changed, 24 insertions(+), 7 deletions(-)
Michael Ellerman - April 19, 2010, 2:46 a.m.
On Fri, 2010-04-16 at 15:34 +0800, Li Yang wrote:
> From: Zhao Chenhui <b26998@freescale.com>
> 
> 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 <b26998@freescale.com>
> Signed-off-by: Li Yang <leoli@freescale.com>
> ---
>  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 <asm/mpic.h>
>  #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
Yang Li - April 19, 2010, 6:46 a.m.
On Mon, Apr 19, 2010 at 10:46 AM, Michael Ellerman
<michael@ellerman.id.au> wrote:
> On Fri, 2010-04-16 at 15:34 +0800, Li Yang wrote:
>> From: Zhao Chenhui <b26998@freescale.com>
>>
>> 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

Patch

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 <asm/mpic.h>
 #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 */