linux-kernel - Re: [PATCH 1/2] fpga: dfl: map feature mmio resources in their own feature drivers

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Date:   Wed, 22 Jul 2020 14:51:07 +0800
From:   Xu Yilun <yilun.xu@...el.com>
To:     Tom Rix <trix@...hat.com>
Cc:     mdf@...nel.org, linux-fpga@...r.kernel.org,
        linux-kernel@...r.kernel.org, lgoncalv@...hat.com,
        Wu Hao <hao.wu@...el.com>,
        Matthew Gerlach <matthew.gerlach@...ux.intel.com>,
        Russ Weight <russell.h.weight@...el.com>
Subject: Re: [PATCH 1/2] fpga: dfl: map feature mmio resources in their own
  feature drivers

Sorry, I missed some comments. Reply inline.

> > +	/* release I/O mappings for next step enumeration */
> > +	cci_pci_iounmap_bars(pcidev, mapped_bars);
> There is no iounmap_bars in error handling, likely need to add this.

The memory allocated by pcim_iomap_xxx will be released along with
pcidev destory.

> > +
> >  	/* start enumeration with prepared enumeration information */
> >  	cdev = dfl_fpga_feature_devs_enumerate(info);
> >  	if (IS_ERR(cdev)) {
> > diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> > index 649958a..7dc6411 100644
> > --- a/drivers/fpga/dfl.c
> > +++ b/drivers/fpga/dfl.c
> > @@ -250,6 +250,11 @@ int dfl_fpga_check_port_id(struct platform_device *pdev, void *pport_id)
> >  }
> >  EXPORT_SYMBOL_GPL(dfl_fpga_check_port_id);
> >  
> > +static bool is_header_feature(struct dfl_feature *feature)
> > +{
> > +	return feature->id == FEATURE_ID_FIU_HEADER;
> Could this be a macro ?

Yes

> > +}
> > +
> >  /**
> >   * dfl_fpga_dev_feature_uinit - uinit for sub features of dfl feature device
> >   * @pdev: feature device.
> > @@ -273,8 +278,20 @@ static int dfl_feature_instance_init(struct platform_device *pdev,
> >  				     struct dfl_feature *feature,
> >  				     struct dfl_feature_driver *drv)
> >  {
> > +	void __iomem *base;
> >  	int ret = 0;
> >  
> > +	if (!is_header_feature(feature)) {
> > +		base = devm_platform_ioremap_resource(pdev,
> > +						      feature->resource_index);
> > +		if (IS_ERR(base)) {
> > +			dev_err(&pdev->dev, "fail to get iomem resource!\n");
> > +			return PTR_ERR(base);
> > +		}
> > +
> > +		feature->ioaddr = base;
> > +	}
> > +
> >  	if (drv->ops->init) {
> >  		ret = drv->ops->init(pdev, feature);
> >  		if (ret)
> > @@ -427,7 +444,9 @@ EXPORT_SYMBOL_GPL(dfl_fpga_dev_ops_unregister);
> >   * @irq_table: Linux IRQ numbers for all irqs, indexed by local irq index of
> >   *	       this device.
> >   * @feature_dev: current feature device.
> > - * @ioaddr: header register region address of feature device in enumeration.
> > + * @ioaddr: header register region address of current FIU in enumeration.
> > + * @start: register resource start of current FIU.
> > + * @len: max register resource length of current FIU.
> >   * @sub_features: a sub features linked list for feature device in enumeration.
> >   * @feature_num: number of sub features for feature device in enumeration.
> >   */
> > @@ -439,6 +458,9 @@ struct build_feature_devs_info {
> >  
> >  	struct platform_device *feature_dev;
> >  	void __iomem *ioaddr;
> > +	resource_size_t start;
> > +	resource_size_t len;
> > +
> extra whitespace, remove

Yes

> >  	struct list_head sub_features;
> >  	int feature_num;
> >  };
> > @@ -484,10 +506,7 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
> >  	struct dfl_feature_platform_data *pdata;
> >  	struct dfl_feature_info *finfo, *p;
> >  	enum dfl_id_type type;
> > -	int ret, index = 0;
> > -
> > -	if (!fdev)
> > -		return 0;
> > +	int ret, index = 0, res_idx = 0;
> >  
> >  	type = feature_dev_id_type(fdev);
> >  	if (WARN_ON_ONCE(type >= DFL_ID_MAX))
> > @@ -530,16 +549,30 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
> >  
> >  	/* fill features and resource information for feature dev */
> >  	list_for_each_entry_safe(finfo, p, &binfo->sub_features, node) {
> > -		struct dfl_feature *feature = &pdata->features[index];
> > +		struct dfl_feature *feature = &pdata->features[index++];
> >  		struct dfl_feature_irq_ctx *ctx;
> >  		unsigned int i;
> >  
> >  		/* save resource information for each feature */
> >  		feature->dev = fdev;
> >  		feature->id = finfo->fid;
> > -		feature->resource_index = index;
> > -		feature->ioaddr = finfo->ioaddr;
> > -		fdev->resource[index++] = finfo->mmio_res;
> > +
> > +		/*
> > +		 * map header resource for dfl bus device. Don't add header
> > +		 * resource to feature devices, or the resource tree will be
> > +		 * disordered and cause warning on resource release
> > +		 */
> > +		if (is_header_feature(feature)) {
> > +			feature->resource_index = -1;
> > +			feature->ioaddr =
> > +				devm_ioremap_resource(binfo->dev,
> > +						      &finfo->mmio_res);
> > +			if (IS_ERR(feature->ioaddr))
> > +				return PTR_ERR(feature->ioaddr);
> feature->ioaddr is garbage, is this ok ?

It should be OK. We will not touch this field during cleaning up.

> > +static bool is_feature_dev_detected(struct build_feature_devs_info *binfo)
> > +{
> > +	return !!binfo->feature_dev;
> Another macro.

Yes

> > +}
> > +
> > +static void dfl_binfo_shift(struct build_feature_devs_info *binfo,
> > +			    resource_size_t ofst)
> shift? where is shifting happening.  A better name would be dfl_binfo_update or dfl_binfo_increment

I'll delete this function, it is not useful.

Thanks,
Yilun