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Subject: Re: [PATCH v4 1/4] fpga: dfl: expose feature revision from struct
 dfl_device
To:     =?UTF-8?Q?Martin_Hundeb=c3=b8ll?= <martin@geanix.com>,
        Wu Hao <hao.wu@intel.com>, Moritz Fischer <mdf@kernel.org>,
        Xu Yilun <yilun.xu@intel.com>,
        Jean Delvare <jdelvare@suse.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Lee Jones <lee.jones@linaro.org>,
        Mark Brown <broonie@kernel.org>
Cc:     =?UTF-8?Q?Martin_Hundeb=c3=b8ll?= <mhu@silicom.dk>,
        linux-fpga@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hwmon@vger.kernel.org, linux-spi@vger.kernel.org,
        Matthew Gerlach <matthew.gerlach@linux.intel.com>
References: <20210705101645.2040106-1-martin@geanix.com>
 <20210705101645.2040106-2-martin@geanix.com>
From:   Tom Rix <trix@redhat.com>
Message-ID: <93a8e949-ec25-d00d-4740-72d9e18ebb68@redhat.com>
Date:   Tue, 6 Jul 2021 07:10:21 -0700
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On 7/5/21 3:16 AM, Martin Hundebøll wrote:
> From: Martin Hundebøll <mhu@silicom.dk>
>
> DFL device drivers have a common need for checking feature revision
> information from the DFL header, as well as other common DFL information
> like the already exposed feature id and type.
>
> This patch exposes the feature revision information directly via the DFL
> device data structure.
>
> Since the DFL core code has already read the DFL header, this this patch
> saves additional mmio reads from DFL device drivers too.
>
> Signed-off-by: Martin Hundebøll <mhu@silicom.dk>
> Acked-by: Wu Hao <hao.wu@intel.com>
> Acked-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> ---
>
> Changes since v3:
>   * Added Hao's Acked-by
>   * Added Matthew's Acked-by
>
> Changes since v2:
>   * Reworded commit message as per Hao's suggestion
>
> Changes since v1:
>   * This patch replaces the previous patch 2 and exposes the feature
>     revision through struct dfl_device instead of a helper reading from
>     io-mem
>
>   drivers/fpga/dfl.c  | 27 +++++++++++++++++----------
>   drivers/fpga/dfl.h  |  1 +
>   include/linux/dfl.h |  1 +
>   3 files changed, 19 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index 511b20ff35a3..9381c579d1cd 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -381,6 +381,7 @@ dfl_dev_add(struct dfl_feature_platform_data *pdata,
>   
>   	ddev->type = feature_dev_id_type(pdev);
>   	ddev->feature_id = feature->id;
> +	ddev->revision = feature->revision;
>   	ddev->cdev = pdata->dfl_cdev;
>   
>   	/* add mmio resource */
> @@ -717,6 +718,7 @@ struct build_feature_devs_info {
>    */
>   struct dfl_feature_info {
>   	u16 fid;
> +	u8 rev;

In other places 'revision' is the element name.

For consistency, change rev to revision

>   	struct resource mmio_res;
>   	void __iomem *ioaddr;
>   	struct list_head node;
> @@ -796,6 +798,7 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
>   		/* save resource information for each feature */
>   		feature->dev = fdev;
>   		feature->id = finfo->fid;
> +		feature->revision = finfo->rev;
>   
>   		/*
>   		 * the FIU header feature has some fundamental functions (sriov
> @@ -910,19 +913,17 @@ static void build_info_free(struct build_feature_devs_info *binfo)
>   	devm_kfree(binfo->dev, binfo);
>   }
>   
> -static inline u32 feature_size(void __iomem *start)
> +static inline u32 feature_size(u64 value)

The return type should match its use in create_feature_instance 
'resource_size_t'

change u32 to resource_size_t

Tom

>   {
> -	u64 v = readq(start + DFH);
> -	u32 ofst = FIELD_GET(DFH_NEXT_HDR_OFST, v);
> +	u32 ofst = FIELD_GET(DFH_NEXT_HDR_OFST, value);
>   	/* workaround for private features with invalid size, use 4K instead */
>   	return ofst ? ofst : 4096;
>   }
>   
> -static u16 feature_id(void __iomem *start)
> +static u16 feature_id(u64 value)
>   {
> -	u64 v = readq(start + DFH);
> -	u16 id = FIELD_GET(DFH_ID, v);
> -	u8 type = FIELD_GET(DFH_TYPE, v);
> +	u16 id = FIELD_GET(DFH_ID, value);
> +	u8 type = FIELD_GET(DFH_TYPE, value);
>   
>   	if (type == DFH_TYPE_FIU)
>   		return FEATURE_ID_FIU_HEADER;
> @@ -1021,10 +1022,15 @@ create_feature_instance(struct build_feature_devs_info *binfo,
>   	unsigned int irq_base, nr_irqs;
>   	struct dfl_feature_info *finfo;
>   	int ret;
> +	u8 rev;
> +	u64 v;
> +
> +	v = readq(binfo->ioaddr + ofst);
> +	rev = FIELD_GET(DFH_REVISION, v);
>   
>   	/* read feature size and id if inputs are invalid */
> -	size = size ? size : feature_size(binfo->ioaddr + ofst);
> -	fid = fid ? fid : feature_id(binfo->ioaddr + ofst);
> +	size = size ? size : feature_size(v);
> +	fid = fid ? fid : feature_id(v);
>   
>   	if (binfo->len - ofst < size)
>   		return -EINVAL;
> @@ -1038,6 +1044,7 @@ create_feature_instance(struct build_feature_devs_info *binfo,
>   		return -ENOMEM;
>   
>   	finfo->fid = fid;
> +	finfo->rev = rev;
>   	finfo->mmio_res.start = binfo->start + ofst;
>   	finfo->mmio_res.end = finfo->mmio_res.start + size - 1;
>   	finfo->mmio_res.flags = IORESOURCE_MEM;
> @@ -1166,7 +1173,7 @@ static int parse_feature_private(struct build_feature_devs_info *binfo,
>   {
>   	if (!is_feature_dev_detected(binfo)) {
>   		dev_err(binfo->dev, "the private feature 0x%x does not belong to any AFU.\n",
> -			feature_id(binfo->ioaddr + ofst));
> +			feature_id(readq(binfo->ioaddr + ofst)));
>   		return -EINVAL;
>   	}
>   
> diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
> index 2b82c96ba56c..422157cfd742 100644
> --- a/drivers/fpga/dfl.h
> +++ b/drivers/fpga/dfl.h
> @@ -243,6 +243,7 @@ struct dfl_feature_irq_ctx {
>   struct dfl_feature {
>   	struct platform_device *dev;
>   	u16 id;
> +	u8 revision;
>   	int resource_index;
>   	void __iomem *ioaddr;
>   	struct dfl_feature_irq_ctx *irq_ctx;
> diff --git a/include/linux/dfl.h b/include/linux/dfl.h
> index 6cc10982351a..431636a0dc78 100644
> --- a/include/linux/dfl.h
> +++ b/include/linux/dfl.h
> @@ -38,6 +38,7 @@ struct dfl_device {
>   	int id;
>   	u16 type;
>   	u16 feature_id;
> +	u8 revision;
>   	struct resource mmio_res;
>   	int *irqs;
>   	unsigned int num_irqs;