Re: [PATCH v4 3/8] of/irq: Break out msi-map lookup (again)

[Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>]

On Fri, Jul 01, 2016 at 05:50:12PM +0100, Robin Murphy wrote:
> The PCI msi-map code is already doing double-duty translating IDs and
> retrieving MSI parents, which unsurprisingly is the same functionality
> we need for the identically-formatted PCI iommu-map property. Drag the
> core parsing routine up yet another layer into the general OF-PCI code,
> and further generalise it for either kind of lookup in either flavour
> of map property.
> 
> CC: Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> CC: Frank Rowand <frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Acked-by: Marc Zyngier <marc.zyngier-5wv7dgnIgG8@public.gmane.org>
> Signed-off-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
> ---
> 
> v4: No change.
> 
>  drivers/of/irq.c       |  78 ++-----------------------------------
>  drivers/of/of_pci.c    | 102 +++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/of_pci.h |  10 +++++
>  3 files changed, 116 insertions(+), 74 deletions(-)

Whilst this looks good to me, I think we need an Ack from the DT
maintainers.

Rob, could you have a look please?

Thanks,

Will

> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> index 6ec743faabe8..091d45e6d61d 100644
> --- a/drivers/of/irq.c
> +++ b/drivers/of/irq.c
> @@ -24,6 +24,7 @@
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_irq.h>
> +#include <linux/of_pci.h>
>  #include <linux/string.h>
>  #include <linux/slab.h>
>  
> @@ -587,87 +588,16 @@ static u32 __of_msi_map_rid(struct device *dev, struct device_node **np,
>  			    u32 rid_in)
>  {
>  	struct device *parent_dev;
> -	struct device_node *msi_controller_node;
> -	struct device_node *msi_np = *np;
> -	u32 map_mask, masked_rid, rid_base, msi_base, rid_len, phandle;
> -	int msi_map_len;
> -	bool matched;
>  	u32 rid_out = rid_in;
> -	const __be32 *msi_map = NULL;
>  
>  	/*
>  	 * Walk up the device parent links looking for one with a
>  	 * "msi-map" property.
>  	 */
> -	for (parent_dev = dev; parent_dev; parent_dev = parent_dev->parent) {
> -		if (!parent_dev->of_node)
> -			continue;
> -
> -		msi_map = of_get_property(parent_dev->of_node,
> -					  "msi-map", &msi_map_len);
> -		if (!msi_map)
> -			continue;
> -
> -		if (msi_map_len % (4 * sizeof(__be32))) {
> -			dev_err(parent_dev, "Error: Bad msi-map length: %d\n",
> -				msi_map_len);
> -			return rid_out;
> -		}
> -		/* We have a good parent_dev and msi_map, let's use them. */
> -		break;
> -	}
> -	if (!msi_map)
> -		return rid_out;
> -
> -	/* The default is to select all bits. */
> -	map_mask = 0xffffffff;
> -
> -	/*
> -	 * Can be overridden by "msi-map-mask" property.  If
> -	 * of_property_read_u32() fails, the default is used.
> -	 */
> -	of_property_read_u32(parent_dev->of_node, "msi-map-mask", &map_mask);
> -
> -	masked_rid = map_mask & rid_in;
> -	matched = false;
> -	while (!matched && msi_map_len >= 4 * sizeof(__be32)) {
> -		rid_base = be32_to_cpup(msi_map + 0);
> -		phandle = be32_to_cpup(msi_map + 1);
> -		msi_base = be32_to_cpup(msi_map + 2);
> -		rid_len = be32_to_cpup(msi_map + 3);
> -
> -		if (rid_base & ~map_mask) {
> -			dev_err(parent_dev,
> -				"Invalid msi-map translation - msi-map-mask (0x%x) ignores rid-base (0x%x)\n",
> -				map_mask, rid_base);
> -			return rid_out;
> -		}
> -
> -		msi_controller_node = of_find_node_by_phandle(phandle);
> -
> -		matched = (masked_rid >= rid_base &&
> -			   masked_rid < rid_base + rid_len);
> -		if (msi_np)
> -			matched &= msi_np == msi_controller_node;
> -
> -		if (matched && !msi_np) {
> -			*np = msi_np = msi_controller_node;
> +	for (parent_dev = dev; parent_dev; parent_dev = parent_dev->parent)
> +		if (!of_pci_map_rid(parent_dev->of_node, rid_in, "msi-map",
> +				    "msi-map-mask", np, &rid_out))
>  			break;
> -		}
> -
> -		of_node_put(msi_controller_node);
> -		msi_map_len -= 4 * sizeof(__be32);
> -		msi_map += 4;
> -	}
> -	if (!matched)
> -		return rid_out;
> -
> -	rid_out = masked_rid - rid_base + msi_base;
> -	dev_dbg(dev,
> -		"msi-map at: %s, using mask %08x, rid-base: %08x, msi-base: %08x, length: %08x, rid: %08x -> %08x\n",
> -		dev_name(parent_dev), map_mask, rid_base, msi_base,
> -		rid_len, rid_in, rid_out);
> -
>  	return rid_out;
>  }
>  
> diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
> index 13f4fed38048..e6465cf7aea9 100644
> --- a/drivers/of/of_pci.c
> +++ b/drivers/of/of_pci.c
> @@ -306,3 +306,105 @@ struct msi_controller *of_pci_find_msi_chip_by_node(struct device_node *of_node)
>  EXPORT_SYMBOL_GPL(of_pci_find_msi_chip_by_node);
>  
>  #endif /* CONFIG_PCI_MSI */
> +
> +/**
> + * of_pci_map_rid - Translate a requester ID through a downstream mapping.
> + * @np: root complex device node.
> + * @rid: PCI requester ID to map.
> + * @map_name: property name of the map to use.
> + * @map_mask_name: optional property name of the mask to use.
> + * @target: optional pointer to a target device node.
> + * @id_out: optional pointer to receive the translated ID.
> + *
> + * Given a PCI requester ID, look up the appropriate implementation-defined
> + * platform ID and/or the target device which receives transactions on that
> + * ID, as per the "iommu-map" and "msi-map" bindings. Either of @target or
> + * @id_out may be NULL if only the other is required. If @target points to
> + * a non-NULL device node pointer, only entries targeting that node will be
> + * matched; if it points to a NULL value, it will receive the device node of
> + * the first matching target phandle, with a reference held.
> + *
> + * Return: 0 on success or a standard error code on failure.
> + */
> +int of_pci_map_rid(struct device_node *np, u32 rid,
> +		   const char *map_name, const char *map_mask_name,
> +		   struct device_node **target, u32 *id_out)
> +{
> +	u32 map_mask, masked_rid;
> +	int map_len;
> +	const __be32 *map = NULL;
> +
> +	if (!np || !map_name || (!target && !id_out))
> +		return -EINVAL;
> +
> +	map = of_get_property(np, map_name, &map_len);
> +	if (!map) {
> +		if (target)
> +			return -ENODEV;
> +		/* Otherwise, no map implies no translation */
> +		*id_out = rid;
> +		return 0;
> +	}
> +
> +	if (!map_len || map_len % (4 * sizeof(*map))) {
> +		pr_err("%s: Error: Bad %s length: %d\n", np->full_name,
> +			map_name, map_len);
> +		return -EINVAL;
> +	}
> +
> +	/* The default is to select all bits. */
> +	map_mask = 0xffffffff;
> +
> +	/*
> +	 * Can be overridden by "{iommu,msi}-map-mask" property.
> +	 * If of_property_read_u32() fails, the default is used.
> +	 */
> +	if (map_mask_name)
> +		of_property_read_u32(np, map_mask_name, &map_mask);
> +
> +	masked_rid = map_mask & rid;
> +	for ( ; map_len > 0; map_len -= 4 * sizeof(*map), map += 4) {
> +		struct device_node *phandle_node;
> +		u32 rid_base = be32_to_cpup(map + 0);
> +		u32 phandle = be32_to_cpup(map + 1);
> +		u32 out_base = be32_to_cpup(map + 2);
> +		u32 rid_len = be32_to_cpup(map + 3);
> +
> +		if (rid_base & ~map_mask) {
> +			pr_err("%s: Invalid %s translation - %s-mask (0x%x) ignores rid-base (0x%x)\n",
> +				np->full_name, map_name, map_name,
> +				map_mask, rid_base);
> +			return -EFAULT;
> +		}
> +
> +		if (masked_rid < rid_base || masked_rid >= rid_base + rid_len)
> +			continue;
> +
> +		phandle_node = of_find_node_by_phandle(phandle);
> +		if (!phandle_node)
> +			return -ENODEV;
> +
> +		if (target) {
> +			if (*target)
> +				of_node_put(phandle_node);
> +			else
> +				*target = phandle_node;
> +
> +			if (*target != phandle_node)
> +				continue;
> +		}
> +
> +		if (id_out)
> +			*id_out = masked_rid - rid_base + out_base;
> +
> +		pr_debug("%s: %s, using mask %08x, rid-base: %08x, out-base: %08x, length: %08x, rid: %08x -> %08x\n",
> +			np->full_name, map_name, map_mask, rid_base, out_base,
> +			rid_len, rid, *id_out);
> +		return 0;
> +	}
> +
> +	pr_err("%s: Invalid %s translation - no match for rid 0x%x on %s\n",
> +		np->full_name, map_name, rid,
> +		target && *target ? (*target)->full_name : "any target");
> +	return -EFAULT;
> +}
> diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
> index b969e9443962..7fd5cfce9140 100644
> --- a/include/linux/of_pci.h
> +++ b/include/linux/of_pci.h
> @@ -17,6 +17,9 @@ int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin);
>  int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
>  int of_get_pci_domain_nr(struct device_node *node);
>  void of_pci_check_probe_only(void);
> +int of_pci_map_rid(struct device_node *np, u32 rid,
> +		   const char *map_name, const char *map_mask_name,
> +		   struct device_node **target, u32 *id_out);
>  #else
>  static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
>  {
> @@ -52,6 +55,13 @@ of_get_pci_domain_nr(struct device_node *node)
>  	return -1;
>  }
>  
> +static inline int of_pci_map_rid(struct device_node *np, u32 rid,
> +			const char *map_name, const char *map_mask_name,
> +			struct device_node **target, u32 *id_out)
> +{
> +	return -EINVAL;
> +}
> +
>  static inline void of_pci_check_probe_only(void) { }
>  #endif
>  
> -- 
> 2.8.1.dirty
> 
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