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Date:   Fri, 2 Jun 2023 17:11:47 +0200
From:   Robert Richter <rrichter@amd.com>
To:     Jonathan Cameron <Jonathan.Cameron@huawei.com>
CC:     Terry Bowman <terry.bowman@amd.com>, <alison.schofield@intel.com>,
        <vishal.l.verma@intel.com>, <ira.weiny@intel.com>,
        <bwidawsk@kernel.org>, <dan.j.williams@intel.com>,
        <dave.jiang@intel.com>, <linux-cxl@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <bhelgaas@google.com>
Subject: Re: [PATCH v4 04/23] cxl/core/regs: Add @dev to cxl_register_map
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On 01.06.23 11:49:30, Jonathan Cameron wrote:
> On Tue, 23 May 2023 18:21:55 -0500
> Terry Bowman <terry.bowman@amd.com> wrote:
> 
> > From: Robert Richter <rrichter@amd.com>
> > 
> > The corresponding device of a register mapping is used for devm
> > operations and logging. For operations with struct cxl_register_map
> > the device needs to be kept track separately. To simpify the involved
> > function interfaces, add @dev to cxl_register_map.
> > 
> > While at it also reorder function arguments of cxl_map_device_regs()
> > and cxl_map_component_regs() to have the object @cxl_register_map
> > first.
> > 
> > In a result a bunch of functions are available to be used with a
> > @cxl_register_map object.
> > 
> > This patch is in preparation of reworking the component register setup
> > code.
> > 
> > Signed-off-by: Robert Richter <rrichter@amd.com>
> > Signed-off-by: Terry Bowman <terry.bowman@amd.com>
> > ---
> >  drivers/cxl/core/hdm.c  |  4 ++--
> >  drivers/cxl/core/regs.c | 22 ++++++++++++---------
> >  drivers/cxl/cxl.h       | 10 ++++++----
> >  drivers/cxl/pci.c       | 42 ++++++++++++++++++++---------------------
> >  4 files changed, 41 insertions(+), 37 deletions(-)
> > 
> > diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> > index 7889ff203a34..5abfa9276dac 100644
> > --- a/drivers/cxl/core/hdm.c
> > +++ b/drivers/cxl/core/hdm.c
> > @@ -85,6 +85,7 @@ static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
> >  				struct cxl_component_regs *regs)
> >  {
> >  	struct cxl_register_map map = {
> > +		.dev = &port->dev,
> >  		.resource = port->component_reg_phys,
> >  		.base = crb,
> >  		.max_size = CXL_COMPONENT_REG_BLOCK_SIZE,
> > @@ -97,8 +98,7 @@ static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
> >  		return -ENODEV;
> >  	}
> >  
> > -	return cxl_map_component_regs(&port->dev, regs, &map,
> > -				      BIT(CXL_CM_CAP_CAP_ID_HDM));
> > +	return cxl_map_component_regs(&map, regs, BIT(CXL_CM_CAP_CAP_ID_HDM));
> >  }
> >  
> >  static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
> > diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
> > index 08da4c917f99..9888bdf43e55 100644
> > --- a/drivers/cxl/core/regs.c
> > +++ b/drivers/cxl/core/regs.c
> > @@ -199,8 +199,9 @@ void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr,
> >  	return ret_val;
> >  }
> >  
> > -int cxl_map_component_regs(struct device *dev, struct cxl_component_regs *regs,
> > -			   struct cxl_register_map *map, unsigned long map_mask)
> > +int cxl_map_component_regs(struct cxl_register_map *map,
> > +			   struct cxl_component_regs *regs,
> > +			   unsigned long map_mask)
> >  {
> >  	struct mapinfo {
> >  		struct cxl_reg_map *rmap;
> > @@ -213,16 +214,16 @@ int cxl_map_component_regs(struct device *dev, struct cxl_component_regs *regs,
> >  
> >  	for (i = 0; i < ARRAY_SIZE(mapinfo); i++) {
> >  		struct mapinfo *mi = &mapinfo[i];
> > -		resource_size_t phys_addr;
> > +		resource_size_t addr;
> 
> This rename not mentioned in the patch description. I guess it's
> stepping towards consistency between the different paths, but
> in this patch it looks like noise...

Haven't added a comment in the description as this is a local change
only and right, also for consistency. But the original intention was
to shorten variable length here to keep the 80 char size limit for the
line.

> 
> >  		resource_size_t length;
> >  
> >  		if (!mi->rmap->valid)
> >  			continue;
> >  		if (!test_bit(mi->rmap->id, &map_mask))
> >  			continue;
> > -		phys_addr = map->resource + mi->rmap->offset;
> > +		addr = map->resource + mi->rmap->offset;
> >  		length = mi->rmap->size;
> > -		*(mi->addr) = devm_cxl_iomap_block(dev, phys_addr, length);
> > +		*(mi->addr) = devm_cxl_iomap_block(map->dev, addr, length);
> >  		if (!*(mi->addr))
> >  			return -ENOMEM;
> >  	}
> > @@ -231,9 +232,8 @@ int cxl_map_component_regs(struct device *dev, struct cxl_component_regs *regs,
> >  }
> >  EXPORT_SYMBOL_NS_GPL(cxl_map_component_regs, CXL);
> >  
> > -int cxl_map_device_regs(struct device *dev,
> > -			struct cxl_device_regs *regs,
> > -			struct cxl_register_map *map)
> > +int cxl_map_device_regs(struct cxl_register_map *map,
> > +			struct cxl_device_regs *regs)
> >  {
> >  	resource_size_t phys_addr = map->resource;
> >  	struct mapinfo {
> > @@ -256,7 +256,7 @@ int cxl_map_device_regs(struct device *dev,
> >  
> >  		addr = phys_addr + mi->rmap->offset;
> >  		length = mi->rmap->size;
> > -		*(mi->addr) = devm_cxl_iomap_block(dev, addr, length);
> > +		*(mi->addr) = devm_cxl_iomap_block(map->dev, addr, length);
> >  		if (!*(mi->addr))
> >  			return -ENOMEM;
> >  	}
> > @@ -302,7 +302,10 @@ int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
> >  	u32 regloc_size, regblocks;
> >  	int regloc, i;
> >  
> > +	memset(map, 0, sizeof(*map));
> > +	map->dev = &pdev->dev;
> >  	map->resource = CXL_RESOURCE_NONE;
> > +
> 
> No comment :)

This logicaly groups the setup of @map in a code block.

> 
> >  	regloc = pci_find_dvsec_capability(pdev, PCI_DVSEC_VENDOR_ID_CXL,
> >  					   CXL_DVSEC_REG_LOCATOR);
> >  	if (!regloc)
> > @@ -328,6 +331,7 @@ int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
> >  	}
> >  
> >  	map->resource = CXL_RESOURCE_NONE;
> > +
> Not here either.
> 
> White space changes go in a patch on their own - not mixed in!

IMO, once touching a function coding style changes can be part of the
whole change. Splitting this in small trivial patches a bit too much
as long as the patch is still readable.

> 
> >  	return -ENODEV;
> >  }
> >  EXPORT_SYMBOL_NS_GPL(cxl_find_regblock, CXL);
> > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> > index a8bda2c74a85..095b767c21e9 100644
> > --- a/drivers/cxl/cxl.h
> > +++ b/drivers/cxl/cxl.h
> > @@ -231,6 +231,7 @@ struct cxl_device_reg_map {
> >  
> >  /**
> >   * struct cxl_register_map - DVSEC harvested register block mapping parameters
> > + * @dev: device for devm operations and logging
> >   * @base: virtual base of the register-block-BAR + @block_offset
> >   * @resource: physical resource base of the register block
> >   * @max_size: maximum mapping size to perform register search
> > @@ -239,6 +240,7 @@ struct cxl_device_reg_map {
> >   * @device_map: cxl_reg_maps for device registers
> >   */
> >  struct cxl_register_map {
> > +	struct device *dev;
> >  	void __iomem *base;
> >  	resource_size_t resource;
> >  	resource_size_t max_size;
> > @@ -253,11 +255,11 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
> >  			      struct cxl_component_reg_map *map);
> >  void cxl_probe_device_regs(struct device *dev, void __iomem *base,
> >  			   struct cxl_device_reg_map *map);
> > -int cxl_map_component_regs(struct device *dev, struct cxl_component_regs *regs,
> > -			   struct cxl_register_map *map,
> > +int cxl_map_component_regs(struct cxl_register_map *map,
> > +			   struct cxl_component_regs *regs,
> >  			   unsigned long map_mask);
> > -int cxl_map_device_regs(struct device *dev, struct cxl_device_regs *regs,
> > -			struct cxl_register_map *map);
> > +int cxl_map_device_regs(struct cxl_register_map *map,
> > +			struct cxl_device_regs *regs);
> >  
> >  enum cxl_regloc_type;
> >  int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
> > diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> > index 0872f2233ed0..2a9f65be148b 100644
> > --- a/drivers/cxl/pci.c
> > +++ b/drivers/cxl/pci.c
> > @@ -274,61 +274,59 @@ static int cxl_pci_setup_mailbox(struct cxl_dev_state *cxlds)
> >  	return 0;
> >  }
> >  
> > -static int cxl_map_regblock(struct pci_dev *pdev, struct cxl_register_map *map)
> > +static int cxl_map_regblock(struct cxl_register_map *map)
> >  {
> > -	struct device *dev = &pdev->dev;
> It think equivalent is still a nice to have + smaller diff which is nice.

I see your point here. Will just reassign @dev.

> 
> 	struct device *dev = &map->dev;
> 
> > -
> >  	map->base = ioremap(map->resource, map->max_size);
> >  	if (!map->base) {
> > -		dev_err(dev, "failed to map registers\n");
> > +		dev_err(map->dev, "failed to map registers\n");
> >  		return -ENOMEM;
> >  	}
> >  
> > -	dev_dbg(dev, "Mapped CXL Memory Device resource %pa\n", &map->resource);
> > +	dev_dbg(map->dev, "Mapped CXL Memory Device resource %pa\n",
> > +		&map->resource);
> > +
> >  	return 0;
> >  }
> >  
> > -static void cxl_unmap_regblock(struct pci_dev *pdev,
> > -			       struct cxl_register_map *map)
> > +static void cxl_unmap_regblock(struct cxl_register_map *map)
> >  {
> >  	iounmap(map->base);
> >  	map->base = NULL;
> >  }
> >  
> > -static int cxl_probe_regs(struct pci_dev *pdev, struct cxl_register_map *map)
> > +static int cxl_probe_regs(struct cxl_register_map *map)
> >  {
> >  	struct cxl_component_reg_map *comp_map;
> >  	struct cxl_device_reg_map *dev_map;
> > -	struct device *dev = &pdev->dev;
> 
> Same comment.  Keep the local variable and this patch gets
> smaller.  I guess there might be a reason for this later in the
> set though.  If there is shout about it in the patch introduction.

I don't think the change is later needed. Let's see.

Thanks,

-Robert

> 
> >  	void __iomem *base = map->base;
> >  
> >  	switch (map->reg_type) {
> >  	case CXL_REGLOC_RBI_COMPONENT:
> >  		comp_map = &map->component_map;
> > -		cxl_probe_component_regs(dev, base, comp_map);
> > +		cxl_probe_component_regs(map->dev, base, comp_map);
> >  		if (!comp_map->hdm_decoder.valid) {
> > -			dev_err(dev, "HDM decoder registers not found\n");
> > +			dev_err(map->dev, "HDM decoder registers not found\n");
> >  			return -ENXIO;
> >  		}
> >  
> >  		if (!comp_map->ras.valid)
> > -			dev_dbg(dev, "RAS registers not found\n");
> > +			dev_dbg(map->dev, "RAS registers not found\n");
> >  
> > -		dev_dbg(dev, "Set up component registers\n");
> > +		dev_dbg(map->dev, "Set up component registers\n");
> >  		break;
> >  	case CXL_REGLOC_RBI_MEMDEV:
> >  		dev_map = &map->device_map;
> > -		cxl_probe_device_regs(dev, base, dev_map);
> > +		cxl_probe_device_regs(map->dev, base, dev_map);
> >  		if (!dev_map->status.valid || !dev_map->mbox.valid ||
> >  		    !dev_map->memdev.valid) {
> > -			dev_err(dev, "registers not found: %s%s%s\n",
> > +			dev_err(map->dev, "registers not found: %s%s%s\n",
> >  				!dev_map->status.valid ? "status " : "",
> >  				!dev_map->mbox.valid ? "mbox " : "",
> >  				!dev_map->memdev.valid ? "memdev " : "");
> >  			return -ENXIO;
> >  		}
> >  
> > -		dev_dbg(dev, "Probing device registers...\n");
> > +		dev_dbg(map->dev, "Probing device registers...\n");
> >  		break;
> >  	default:
> >  		break;
> > @@ -346,12 +344,12 @@ static int cxl_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
> >  	if (rc)
> >  		return rc;
> >  
> > -	rc = cxl_map_regblock(pdev, map);
> > +	rc = cxl_map_regblock(map);
> >  	if (rc)
> >  		return rc;
> >  
> > -	rc = cxl_probe_regs(pdev, map);
> > -	cxl_unmap_regblock(pdev, map);
> > +	rc = cxl_probe_regs(map);
> > +	cxl_unmap_regblock(map);
> >  
> >  	return rc;
> >  }
> > @@ -688,7 +686,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> >  	if (rc)
> >  		return rc;
> >  
> > -	rc = cxl_map_device_regs(&pdev->dev, &cxlds->regs.device_regs, &map);
> > +	rc = cxl_map_device_regs(&map, &cxlds->regs.device_regs);
> >  	if (rc)
> >  		return rc;
> >  
> > @@ -703,8 +701,8 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> >  
> >  	cxlds->component_reg_phys = map.resource;
> >  
> > -	rc = cxl_map_component_regs(&pdev->dev, &cxlds->regs.component,
> > -				    &map, BIT(CXL_CM_CAP_CAP_ID_RAS));
> > +	rc = cxl_map_component_regs(&map, &cxlds->regs.component,
> > +				    BIT(CXL_CM_CAP_CAP_ID_RAS));
> >  	if (rc)
> >  		dev_dbg(&pdev->dev, "Failed to map RAS capability.\n");
> >  
>