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[PATCH 05/10] PCI/ATS: Use FIELD_GET()

Bjorn Helgaas posted 10 patches 2 years, 2 months ago
[PATCH 05/10] PCI/ATS: Use FIELD_GET()
Posted by Bjorn Helgaas 2 years, 2 months ago 
From: Bjorn Helgaas <bhelgaas@google.com>

Use FIELD_GET() to remove dependences on the field position, i.e., the
shift value.  No functional change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/ats.c             | 7 ++-----
 include/uapi/linux/pci_regs.h | 1 +
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index f9cc2e10b676..c570892b2090 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -9,6 +9,7 @@
  * Copyright (C) 2011 Advanced Micro Devices,
  */
 
+#include <linux/bitfield.h>
 #include <linux/export.h>
 #include <linux/pci-ats.h>
 #include <linux/pci.h>
@@ -480,8 +481,6 @@ int pci_pasid_features(struct pci_dev *pdev)
 }
 EXPORT_SYMBOL_GPL(pci_pasid_features);
 
-#define PASID_NUMBER_SHIFT	8
-#define PASID_NUMBER_MASK	(0x1f << PASID_NUMBER_SHIFT)
 /**
  * pci_max_pasids - Get maximum number of PASIDs supported by device
  * @pdev: PCI device structure
@@ -503,9 +502,7 @@ int pci_max_pasids(struct pci_dev *pdev)
 
 	pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported);
 
-	supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT;
-
-	return (1 << supported);
+	return (1 << FIELD_GET(PCI_PASID_CAP_WIDTH, supported));
 }
 EXPORT_SYMBOL_GPL(pci_max_pasids);
 #endif /* CONFIG_PCI_PASID */
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 6af1f8d53e97..833e5fb40ea5 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -932,6 +932,7 @@
 #define PCI_PASID_CAP		0x04    /* PASID feature register */
 #define  PCI_PASID_CAP_EXEC	0x0002	/* Exec permissions Supported */
 #define  PCI_PASID_CAP_PRIV	0x0004	/* Privilege Mode Supported */
+#define  PCI_PASID_CAP_WIDTH	0x1f00
 #define PCI_PASID_CTRL		0x06    /* PASID control register */
 #define  PCI_PASID_CTRL_ENABLE	0x0001	/* Enable bit */
 #define  PCI_PASID_CTRL_EXEC	0x0002	/* Exec permissions Enable */
-- 
2.34.1
Re: [PATCH 05/10] PCI/ATS: Use FIELD_GET()
Posted by Ilpo Järvinen 2 years, 2 months ago 
On Tue, 10 Oct 2023, Bjorn Helgaas wrote:

> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> Use FIELD_GET() to remove dependences on the field position, i.e., the
> shift value.  No functional change intended.
> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> ---
>  drivers/pci/ats.c             | 7 ++-----
>  include/uapi/linux/pci_regs.h | 1 +
>  2 files changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
> index f9cc2e10b676..c570892b2090 100644
> --- a/drivers/pci/ats.c
> +++ b/drivers/pci/ats.c
> @@ -9,6 +9,7 @@
>   * Copyright (C) 2011 Advanced Micro Devices,
>   */
>  
> +#include <linux/bitfield.h>
>  #include <linux/export.h>
>  #include <linux/pci-ats.h>
>  #include <linux/pci.h>
> @@ -480,8 +481,6 @@ int pci_pasid_features(struct pci_dev *pdev)
>  }
>  EXPORT_SYMBOL_GPL(pci_pasid_features);
>  
> -#define PASID_NUMBER_SHIFT	8
> -#define PASID_NUMBER_MASK	(0x1f << PASID_NUMBER_SHIFT)
>  /**
>   * pci_max_pasids - Get maximum number of PASIDs supported by device
>   * @pdev: PCI device structure
> @@ -503,9 +502,7 @@ int pci_max_pasids(struct pci_dev *pdev)
>  
>  	pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported);
>  
> -	supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT;
> -
> -	return (1 << supported);
> +	return (1 << FIELD_GET(PCI_PASID_CAP_WIDTH, supported));
>  }
>  EXPORT_SYMBOL_GPL(pci_max_pasids);
>  #endif /* CONFIG_PCI_PASID */
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index 6af1f8d53e97..833e5fb40ea5 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -932,6 +932,7 @@
>  #define PCI_PASID_CAP		0x04    /* PASID feature register */
>  #define  PCI_PASID_CAP_EXEC	0x0002	/* Exec permissions Supported */
>  #define  PCI_PASID_CAP_PRIV	0x0004	/* Privilege Mode Supported */
> +#define  PCI_PASID_CAP_WIDTH	0x1f00
>  #define PCI_PASID_CTRL		0x06    /* PASID control register */
>  #define  PCI_PASID_CTRL_ENABLE	0x0001	/* Enable bit */
>  #define  PCI_PASID_CTRL_EXEC	0x0002	/* Exec permissions Enable */

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

-- 
 i.
Re: [PATCH 05/10] PCI/ATS: Use FIELD_GET()
Posted by Jonathan Cameron 2 years, 2 months ago 
On Tue, 10 Oct 2023 15:44:31 -0500
Bjorn Helgaas <helgaas@kernel.org> wrote:

> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> Use FIELD_GET() to remove dependences on the field position, i.e., the
> shift value.  No functional change intended.
> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
One trivial comment inline. Either way.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  drivers/pci/ats.c             | 7 ++-----
>  include/uapi/linux/pci_regs.h | 1 +
>  2 files changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
> index f9cc2e10b676..c570892b2090 100644
> --- a/drivers/pci/ats.c
> +++ b/drivers/pci/ats.c
> @@ -9,6 +9,7 @@
>   * Copyright (C) 2011 Advanced Micro Devices,
>   */
>  
> +#include <linux/bitfield.h>
>  #include <linux/export.h>
>  #include <linux/pci-ats.h>
>  #include <linux/pci.h>
> @@ -480,8 +481,6 @@ int pci_pasid_features(struct pci_dev *pdev)
>  }
>  EXPORT_SYMBOL_GPL(pci_pasid_features);
>  
> -#define PASID_NUMBER_SHIFT	8
> -#define PASID_NUMBER_MASK	(0x1f << PASID_NUMBER_SHIFT)
>  /**
>   * pci_max_pasids - Get maximum number of PASIDs supported by device
>   * @pdev: PCI device structure
> @@ -503,9 +502,7 @@ int pci_max_pasids(struct pci_dev *pdev)
>  
>  	pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported);
>  
> -	supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT;
> -
> -	return (1 << supported);
> +	return (1 << FIELD_GET(PCI_PASID_CAP_WIDTH, supported));

Could drop the bonus set of brackets..

>  }
>  EXPORT_SYMBOL_GPL(pci_max_pasids);
>  #endif /* CONFIG_PCI_PASID */
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index 6af1f8d53e97..833e5fb40ea5 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -932,6 +932,7 @@
>  #define PCI_PASID_CAP		0x04    /* PASID feature register */
>  #define  PCI_PASID_CAP_EXEC	0x0002	/* Exec permissions Supported */
>  #define  PCI_PASID_CAP_PRIV	0x0004	/* Privilege Mode Supported */
> +#define  PCI_PASID_CAP_WIDTH	0x1f00
>  #define PCI_PASID_CTRL		0x06    /* PASID control register */
>  #define  PCI_PASID_CTRL_ENABLE	0x0001	/* Enable bit */
>  #define  PCI_PASID_CTRL_EXEC	0x0002	/* Exec permissions Enable */

Patchew 2.1-devel-b67e4c2

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