linux-kernel - Re: [PATCH v2 1/4] VFIO: platform: add reset struct and lookup table

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Message-ID: <55782357.9070601@linaro.org>
Date:	Wed, 10 Jun 2015 13:45:27 +0200
From:	Eric Auger <eric.auger@...aro.org>
To:	Alex Williamson <alex.williamson@...hat.com>
CC:	b.reynal@...tualopensystems.com, patches@...aro.org,
	linux-kernel@...r.kernel.org, agraf@...e.de,
	linux-arm-kernel@...ts.infradead.org, eric.auger@...com,
	christoffer.dall@...aro.org
Subject: Re: [PATCH v2 1/4] VFIO: platform: add reset struct and lookup table

Hi Alex,
On 06/09/2015 08:26 PM, Alex Williamson wrote:
> On Fri, 2015-06-05 at 17:06 +0200, Eric Auger wrote:
>> This patch introduces the vfio_platform_reset_combo struct that
>> stores all the information useful to handle the reset modality:
>> compat string, name of the reset function, name of the module that
>> implements the reset function. A lookup table of such structures
>> is added, currently containing a single sentinel element. A new
>> type field is added in vfio_platform_device to store what kind of
>> reset is associated to the device, if any.
>>
>> Signed-off-by: Eric Auger <eric.auger@...aro.org>
>> ---
>>  drivers/vfio/platform/vfio_platform_common.c  |  6 ++++++
>>  drivers/vfio/platform/vfio_platform_private.h | 12 ++++++++++++
>>  2 files changed, 18 insertions(+)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
>> index abcff7a..d970776 100644
>> --- a/drivers/vfio/platform/vfio_platform_common.c
>> +++ b/drivers/vfio/platform/vfio_platform_common.c
>> @@ -25,6 +25,12 @@
>>  
>>  static DEFINE_MUTEX(driver_lock);
>>  
>> +static const struct vfio_platform_reset_combo reset_lookup_table[] = {
>> +	{
>> +		.type = VFIO_PLATFORM_RESET_TYPE_MAX
>> +	},
>> +};
>> +
>>  static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
>>  {
>>  	int cnt = 0, i;
>> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
>> index 5d31e04..d864124 100644
>> --- a/drivers/vfio/platform/vfio_platform_private.h
>> +++ b/drivers/vfio/platform/vfio_platform_private.h
>> @@ -49,6 +49,10 @@ struct vfio_platform_region {
>>  	void __iomem		*ioaddr;
>>  };
>>  
>> +enum vfio_platform_reset_type {
>> +	VFIO_PLATFORM_RESET_TYPE_MAX /* last element */,
>> +};
>> +
>>  struct vfio_platform_device {
>>  	struct vfio_platform_region	*regions;
>>  	u32				num_regions;
>> @@ -56,6 +60,7 @@ struct vfio_platform_device {
>>  	u32				num_irqs;
>>  	int				refcnt;
>>  	struct mutex			igate;
>> +	enum vfio_platform_reset_type	type;
>>  
>>  	/*
>>  	 * These fields should be filled by the bus specific binder
>> @@ -69,6 +74,13 @@ struct vfio_platform_device {
>>  	int	(*get_irq)(struct vfio_platform_device *vdev, int i);
>>  };
>>  
>> +struct vfio_platform_reset_combo {
>> +	enum vfio_platform_reset_type type;
>> +	char *compat;
>> +	char *reset_function_name;
>> +	char *module_name;
>> +};
>> +
> 
> I don't really understand the benefit of vfio_platform_reset_type, what
> does it add?  If we want an array end marker, we could just use NULL,
> but if we're dealing with a static table, we could always use ARRAY_SIZE
> and avoid an end marker altogether.  If the concern is matching the
> symbol to put when the device is released, we could just use
> symbol_put_addr() and avoid any sort of lookup.  Seems like there could
> also be a smattering of "const" in this struct definition too.

Agreed. I will respin accordingly.

Best Regards

Eric
> 
>>  extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,
>>  				      struct device *dev);
>>  extern struct vfio_platform_device *vfio_platform_remove_common
> 
> 
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

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