RE: [PATCH v4 2/4] fpga: dfl: map feature mmio resources in their own feature drivers

[Wu, Hao]

> -----Original Message-----
> From: linux-fpga-owner@xxxxxxxxxxxxxxx <linux-fpga-owner@xxxxxxxxxxxxxxx>
> On Behalf Of Xu Yilun
> Sent: Monday, August 10, 2020 10:41 AM
> To: mdf@xxxxxxxxxx; linux-fpga@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Cc: trix@xxxxxxxxxx; lgoncalv@xxxxxxxxxx; Xu, Yilun <yilun.xu@xxxxxxxxx>;
> Wu, Hao <hao.wu@xxxxxxxxx>; Matthew Gerlach
> <matthew.gerlach@xxxxxxxxxxxxxxx>; Weight, Russell H
> <russell.h.weight@xxxxxxxxx>
> Subject: [PATCH v4 2/4] fpga: dfl: map feature mmio resources in their own
> feature drivers
> 
> This patch makes preparation for modularization of DFL sub feature
> drivers.
> 
> Currently, if we need to support a new DFL sub feature, an entry should
> be added to fme/port_feature_drvs[] in dfl-fme/port-main.c. And we need

I think it's afu-main.c

> to re-compile the whole DFL modules. That make the DFL drivers hard to be
> extended.

And maybe we can drop this description or move it to cover letter as it's not
the problem this patch is going to resolve.

> 
> Another consideration is that DFL may contain some IP blocks which are
> already supported by kernel, most of them are supported by platform
> device drivers. We could create platform devices for these IP blocks and
> get them supported by these drivers.
> 
> An important issue is that platform device drivers usually requests mmio
> resources on probe. But now dfl mmio is mapped in dfl bus driver (e.g.
> dfl-pci) as a whole region. Then platform device drivers for sub features
> can't request their own mmio resources again. This is what the patch
> trying to resolve.
> 
> This patch changes the DFL enumeration. DFL bus driver will unmap mmio
> resources after first step enumeration and pass enumeration info to DFL
> framework. Then DFL framework will map the mmio resources again, do 2nd
> step enumeration, and also unmap the mmio resources. In this way, sub
> feature drivers could then request their own mmio resources as needed.
> 
> An exception is that mmio resource of FIU headers are still mapped in dfl
> bus driver. The FIU headers have some fundamental functions (sriov set,
> port enable/disable) needed for dfl bus devices and other sub features.
> They should not be unmapped as long as dfl bus device is alive.
> 
> Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
> Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
> Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
> Acked-by: Wu Hao <hao.wu@xxxxxxxxx>
> ---
> v2: delete dfl_binfo_shift() cause no shift is possible for FIU parsing.
>     Only map bar0 for first phase enumeration in dfl-pci, we can find
>       all dfl mmio resource info in bar0.
>     Some minor fixes for comments from Hao & Tom.
> v3: no change
> v4: minor fixes for Hao's comments.
> ---
>  drivers/fpga/dfl-pci.c |  24 +++----
>  drivers/fpga/dfl.c     | 185 +++++++++++++++++++++++++++++++++--------------
> --
>  drivers/fpga/dfl.h     |   7 +-
>  3 files changed, 139 insertions(+), 77 deletions(-)
> 
> diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
> index e220bec..a2203d0 100644
> --- a/drivers/fpga/dfl-pci.c
> +++ b/drivers/fpga/dfl-pci.c
> @@ -31,12 +31,12 @@ struct cci_drvdata {
>  	struct dfl_fpga_cdev *cdev;	/* container device */
>  };
> 
> -static void __iomem *cci_pci_ioremap_bar(struct pci_dev *pcidev, int bar)
> +static void __iomem *cci_pci_ioremap_bar0(struct pci_dev *pcidev)
>  {
> -	if (pcim_iomap_regions(pcidev, BIT(bar), DRV_NAME))
> +	if (pcim_iomap_regions(pcidev, BIT(0), DRV_NAME))
>  		return NULL;
> 
> -	return pcim_iomap_table(pcidev)[bar];
> +	return pcim_iomap_table(pcidev)[0];
>  }
> 
>  static int cci_pci_alloc_irq(struct pci_dev *pcidev)
> @@ -156,8 +156,8 @@ static int cci_enumerate_feature_devs(struct pci_dev
> *pcidev)
>  			goto irq_free_exit;
>  	}
> 
> -	/* start to find Device Feature List from Bar 0 */
> -	base = cci_pci_ioremap_bar(pcidev, 0);
> +	/* start to find Device Feature List in Bar 0 */
> +	base = cci_pci_ioremap_bar0(pcidev);
>  	if (!base) {
>  		ret = -ENOMEM;
>  		goto irq_free_exit;
> @@ -172,7 +172,7 @@ static int cci_enumerate_feature_devs(struct pci_dev
> *pcidev)
>  		start = pci_resource_start(pcidev, 0);
>  		len = pci_resource_len(pcidev, 0);
> 
> -		dfl_fpga_enum_info_add_dfl(info, start, len, base);
> +		dfl_fpga_enum_info_add_dfl(info, start, len);
> 
>  		/*
>  		 * find more Device Feature Lists (e.g. Ports) per information
> @@ -196,26 +196,24 @@ static int cci_enumerate_feature_devs(struct
> pci_dev *pcidev)
>  			 */
>  			bar = FIELD_GET(FME_PORT_OFST_BAR_ID, v);
>  			offset = FIELD_GET(FME_PORT_OFST_DFH_OFST, v);
> -			base = cci_pci_ioremap_bar(pcidev, bar);
> -			if (!base)
> -				continue;
> -
>  			start = pci_resource_start(pcidev, bar) + offset;
>  			len = pci_resource_len(pcidev, bar) - offset;
> 
> -			dfl_fpga_enum_info_add_dfl(info, start, len,
> -						   base + offset);
> +			dfl_fpga_enum_info_add_dfl(info, start, len);
>  		}
>  	} else if (dfl_feature_is_port(base)) {
>  		start = pci_resource_start(pcidev, 0);
>  		len = pci_resource_len(pcidev, 0);
> 
> -		dfl_fpga_enum_info_add_dfl(info, start, len, base);
> +		dfl_fpga_enum_info_add_dfl(info, start, len);
>  	} else {
>  		ret = -ENODEV;
>  		goto irq_free_exit;
>  	}
> 
> +	/* release I/O mappings for next step enumeration */
> +	pcim_iounmap_regions(pcidev, BIT(0));
> +
>  	/* 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 18575d9..b5257d7 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -250,6 +250,8 @@ int dfl_fpga_check_port_id(struct platform_device
> *pdev, void *pport_id)
>  }
>  EXPORT_SYMBOL_GPL(dfl_fpga_check_port_id);
> 
> +#define is_header_feature(feature) ((feature)->id ==
> FEATURE_ID_FIU_HEADER)
> +
>  /**
>   * dfl_fpga_dev_feature_uinit - uinit for sub features of dfl feature device
>   * @pdev: feature device.
> @@ -273,8 +275,22 @@ 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,
> +				"ioremap failed for feature 0x%x!\n",
> +				feature->id);
> +			return PTR_ERR(base);
> +		}
> +
> +		feature->ioaddr = base;
> +	}
> +
>  	if (drv->ops->init) {
>  		ret = drv->ops->init(pdev, feature);
>  		if (ret)
> @@ -427,7 +443,9 @@ 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 +457,8 @@ struct build_feature_devs_info {
> 
>  	struct platform_device *feature_dev;
>  	void __iomem *ioaddr;
> +	resource_size_t start;
> +	resource_size_t len;
>  	struct list_head sub_features;
>  	int feature_num;
>  };
> @@ -484,10 +504,7 @@ 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 +547,30 @@ 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

I didn't get this description well, could you please explain it a little more
here?

> +		 */
> +		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);
> +		} else {
> +			feature->resource_index = res_idx;
> +			fdev->resource[res_idx++] = finfo->mmio_res;
> +		}
> 
>  		if (finfo->nr_irqs) {
>  			ctx = devm_kcalloc(binfo->dev, finfo->nr_irqs,
> @@ -582,19 +613,13 @@ static int build_info_commit_dev(struct
> build_feature_devs_info *binfo)
> 
>  static int
>  build_info_create_dev(struct build_feature_devs_info *binfo,
> -		      enum dfl_id_type type, void __iomem *ioaddr)
> +		      enum dfl_id_type type)
>  {
>  	struct platform_device *fdev;
> -	int ret;
> 
>  	if (type >= DFL_ID_MAX)
>  		return -EINVAL;
> 
> -	/* we will create a new device, commit current device first */
> -	ret = build_info_commit_dev(binfo);
> -	if (ret)
> -		return ret;
> -
>  	/*
>  	 * we use -ENODEV as the initialization indicator which indicates
>  	 * whether the id need to be reclaimed
> @@ -605,7 +630,7 @@ build_info_create_dev(struct
> build_feature_devs_info *binfo,
> 
>  	binfo->feature_dev = fdev;
>  	binfo->feature_num = 0;
> -	binfo->ioaddr = ioaddr;
> +
>  	INIT_LIST_HEAD(&binfo->sub_features);
> 
>  	fdev->id = dfl_id_alloc(type, &fdev->dev);
> @@ -747,18 +772,17 @@ static int parse_feature_irqs(struct
> build_feature_devs_info *binfo,
>   */
>  static int
>  create_feature_instance(struct build_feature_devs_info *binfo,
> -			struct dfl_fpga_enum_dfl *dfl, resource_size_t ofst,
> -			resource_size_t size, u16 fid)
> +			resource_size_t ofst, resource_size_t size, u16 fid)
>  {
>  	unsigned int irq_base, nr_irqs;
>  	struct dfl_feature_info *finfo;
>  	int ret;
> 
>  	/* read feature size and id if inputs are invalid */
> -	size = size ? size : feature_size(dfl->ioaddr + ofst);
> -	fid = fid ? fid : feature_id(dfl->ioaddr + ofst);
> +	size = size ? size : feature_size(binfo->ioaddr + ofst);
> +	fid = fid ? fid : feature_id(binfo->ioaddr + ofst);
> 
> -	if (dfl->len - ofst < size)
> +	if (binfo->len - ofst < size)
>  		return -EINVAL;
> 
>  	ret = parse_feature_irqs(binfo, ofst, fid, &irq_base, &nr_irqs);
> @@ -770,12 +794,11 @@ create_feature_instance(struct
> build_feature_devs_info *binfo,
>  		return -ENOMEM;
> 
>  	finfo->fid = fid;
> -	finfo->mmio_res.start = dfl->start + ofst;
> +	finfo->mmio_res.start = binfo->start + ofst;
>  	finfo->mmio_res.end = finfo->mmio_res.start + size - 1;
>  	finfo->mmio_res.flags = IORESOURCE_MEM;
>  	finfo->irq_base = irq_base;
>  	finfo->nr_irqs = nr_irqs;
> -	finfo->ioaddr = dfl->ioaddr + ofst;
> 
>  	list_add_tail(&finfo->node, &binfo->sub_features);
>  	binfo->feature_num++;
> @@ -784,7 +807,6 @@ create_feature_instance(struct
> build_feature_devs_info *binfo,
>  }
> 
>  static int parse_feature_port_afu(struct build_feature_devs_info *binfo,
> -				  struct dfl_fpga_enum_dfl *dfl,
>  				  resource_size_t ofst)
>  {
>  	u64 v = readq(binfo->ioaddr + PORT_HDR_CAP);
> @@ -792,21 +814,22 @@ static int parse_feature_port_afu(struct
> build_feature_devs_info *binfo,
> 
>  	WARN_ON(!size);
> 
> -	return create_feature_instance(binfo, dfl, ofst, size,
> FEATURE_ID_AFU);
> +	return create_feature_instance(binfo, ofst, size, FEATURE_ID_AFU);
>  }
> 
> +#define is_feature_dev_detected(binfo) (!!(binfo)->feature_dev)
> +
>  static int parse_feature_afu(struct build_feature_devs_info *binfo,
> -			     struct dfl_fpga_enum_dfl *dfl,
>  			     resource_size_t ofst)
>  {
> -	if (!binfo->feature_dev) {
> +	if (!is_feature_dev_detected(binfo)) {
>  		dev_err(binfo->dev, "this AFU does not belong to any
> FIU.\n");
>  		return -EINVAL;
>  	}
> 
>  	switch (feature_dev_id_type(binfo->feature_dev)) {
>  	case PORT_ID:
> -		return parse_feature_port_afu(binfo, dfl, ofst);
> +		return parse_feature_port_afu(binfo, ofst);
>  	default:
>  		dev_info(binfo->dev, "AFU belonging to FIU %s is not
> supported yet.\n",
>  			 binfo->feature_dev->name);
> @@ -815,8 +838,39 @@ static int parse_feature_afu(struct
> build_feature_devs_info *binfo,
>  	return 0;
>  }
> 
> +static int dfl_binfo_prepare(struct build_feature_devs_info *binfo,
> +			     resource_size_t start, resource_size_t len)
> +{
> +	struct device *dev = binfo->dev;
> +	void __iomem *ioaddr;
> +
> +	if (!devm_request_mem_region(dev, start, len, dev_name(dev))) {
> +		dev_err(dev, "request region fail, start:%pa, len:%pa\n",
> +			&start, &len);
> +		return -EBUSY;
> +	}
> +
> +	ioaddr = devm_ioremap(dev, start, len);
> +	if (!ioaddr) {
> +		dev_err(dev, "ioremap region fail, start:%pa, len:%pa\n",
> +			&start, &len);
> +		return -ENOMEM;
> +	}
> +
> +	binfo->start = start;
> +	binfo->len = len;
> +	binfo->ioaddr = ioaddr;
> +
> +	return 0;
> +}
> +
> +static void dfl_binfo_complete(struct build_feature_devs_info *binfo)
> +{
> +	devm_iounmap(binfo->dev, binfo->ioaddr);
> +	devm_release_mem_region(binfo->dev, binfo->start, binfo->len);
> +}
> +
>  static int parse_feature_fiu(struct build_feature_devs_info *binfo,
> -			     struct dfl_fpga_enum_dfl *dfl,
>  			     resource_size_t ofst)
>  {
>  	int ret = 0;
> @@ -824,27 +878,39 @@ static int parse_feature_fiu(struct
> build_feature_devs_info *binfo,
>  	u16 id;
>  	u64 v;
> 
> -	v = readq(dfl->ioaddr + ofst + DFH);
> +	if (is_feature_dev_detected(binfo)) {
> +		dfl_binfo_complete(binfo);

Some functions are dfl_bind_xxxx but other are build_info_xxxx.
If possible, could we unify them using same format? E.g.
build_info_prepare/complete_xxx

Thanks
Hao