RE: [PATCH 2/6 v2] iommu: of: make of_pci_map_rid() available for other devices too

[Bharat Bhushan <bharat.bhushan@nxp.com>]

> -----Original Message-----
> From: Robin Murphy [mailto:robin.murphy@arm.com]
> Sent: Tuesday, April 17, 2018 10:23 PM
> To: Nipun Gupta <nipun.gupta@nxp.com>; robh+dt@kernel.org;
> frowand.list@gmail.com
> Cc: will.deacon@arm.com; mark.rutland@arm.com; catalin.marinas@arm.com;
> hch@lst.de; gregkh@linuxfoundation.org; joro@8bytes.org;
> m.szyprowski@samsung.com; shawnguo@kernel.org; bhelgaas@google.com;
> iommu@lists.linux-foundation.org; linux-kernel@vger.kernel.org;
> devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linuxppc-
> dev@lists.ozlabs.org; linux-pci@vger.kernel.org; Bharat Bhushan
> <bharat.bhushan@nxp.com>; stuyoder@gmail.com; Laurentiu Tudor
> <laurentiu.tudor@nxp.com>; Leo Li <leoyang.li@nxp.com>
> Subject: Re: [PATCH 2/6 v2] iommu: of: make of_pci_map_rid() available for
> other devices too
> 
> On 17/04/18 11:21, Nipun Gupta wrote:
> > iommu-map property is also used by devices with fsl-mc. This patch
> > moves the of_pci_map_rid to generic location, so that it can be used
> > by other busses too.

Nipun, please clarify that only function name is changed and rest of body is same.

> >
> > Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
> > ---
> >   drivers/iommu/of_iommu.c | 106
> > +++++++++++++++++++++++++++++++++++++++++++++--
> 
> Doesn't this break "msi-parent" parsing for !CONFIG_OF_IOMMU?

Yes, this will be a problem with MSI 

> I guess you
> don't want fsl-mc to have to depend on PCI, but this looks like a step in the
> wrong direction.
> 
> I'm not entirely sure where of_map_rid() fits best, but from a quick look around
> the least-worst option might be drivers/of/of_address.c, unless Rob and Frank
> have a better idea of where generic DT-based ID translation routines could live?

drivers/of/address.c may be proper place to move until someone have better idea.

Thanks
-Bharat

> 
> >   drivers/of/irq.c         |   6 +--
> >   drivers/pci/of.c         | 101 --------------------------------------------
> >   include/linux/of_iommu.h |  11 +++++
> >   include/linux/of_pci.h   |  10 -----
> >   5 files changed, 117 insertions(+), 117 deletions(-)
> >
> > diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c index
> > 5c36a8b..4e7712f 100644
> > --- a/drivers/iommu/of_iommu.c
> > +++ b/drivers/iommu/of_iommu.c
> > @@ -138,6 +138,106 @@ static int of_iommu_xlate(struct device *dev,
> >   	return ops->of_xlate(dev, iommu_spec);
> >   }
> >
> > +/**
> > + * of_map_rid - Translate a requester ID through a downstream mapping.
> > + * @np: root complex device node.
> > + * @rid: device 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 device 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_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("%pOF: Error: Bad %s length: %d\n", np,
> > +			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 (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("%pOF: Invalid %s translation - %s-mask (0x%x)
> ignores rid-base (0x%x)\n",
> > +				np, 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("%pOF: %s, using mask %08x, rid-base: %08x, out-
> base: %08x, length: %08x, rid: %08x -> %08x\n",
> > +			np, map_name, map_mask, rid_base, out_base,
> > +			rid_len, rid, masked_rid - rid_base + out_base);
> > +		return 0;
> > +	}
> > +
> > +	pr_err("%pOF: Invalid %s translation - no match for rid 0x%x on
> %pOF\n",
> > +		np, map_name, rid, target && *target ? *target : NULL);
> > +	return -EFAULT;
> > +}
> > +
> >   struct of_pci_iommu_alias_info {
> >   	struct device *dev;
> >   	struct device_node *np;
> > @@ -149,9 +249,9 @@ static int of_pci_iommu_init(struct pci_dev *pdev, u16
> alias, void *data)
> >   	struct of_phandle_args iommu_spec = { .args_count = 1 };
> >   	int err;
> >
> > -	err = of_pci_map_rid(info->np, alias, "iommu-map",
> > -			     "iommu-map-mask", &iommu_spec.np,
> > -			     iommu_spec.args);
> > +	err = of_map_rid(info->np, alias, "iommu-map",
> > +			 "iommu-map-mask", &iommu_spec.np,
> > +			 iommu_spec.args);
> 
> Super-nit: Apparently I missed rewrapping this to 2 lines in d87beb749281, but if
> it's being touched again, that would be nice ;)
> 
> Robin.
> 
> >   	if (err)
> >   		return err == -ENODEV ? NO_IOMMU : err;
> >
> > diff --git a/drivers/of/irq.c b/drivers/of/irq.c index
> > 02ad93a..b72eeec 100644
> > --- a/drivers/of/irq.c
> > +++ b/drivers/of/irq.c
> > @@ -22,7 +22,7 @@
> >   #include <linux/module.h>
> >   #include <linux/of.h>
> >   #include <linux/of_irq.h>
> > -#include <linux/of_pci.h>
> > +#include <linux/of_iommu.h>
> >   #include <linux/string.h>
> >   #include <linux/slab.h>
> >
> > @@ -588,8 +588,8 @@ static u32 __of_msi_map_rid(struct device *dev,
> struct device_node **np,
> >   	 * "msi-map" property.
> >   	 */
> >   	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))
> > +		if (!of_map_rid(parent_dev->of_node, rid_in, "msi-map",
> > +				"msi-map-mask", np, &rid_out))
> >   			break;
> >   	return rid_out;
> >   }
> > diff --git a/drivers/pci/of.c b/drivers/pci/of.c index
> > a28355c..d2cebbe 100644
> > --- a/drivers/pci/of.c
> > +++ b/drivers/pci/of.c
> > @@ -362,107 +362,6 @@ int of_pci_get_host_bridge_resources(struct
> device_node *dev,
> >   EXPORT_SYMBOL_GPL(of_pci_get_host_bridge_resources);
> >   #endif /* CONFIG_OF_ADDRESS */
> >
> > -/**
> > - * 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("%pOF: Error: Bad %s length: %d\n", np,
> > -			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("%pOF: Invalid %s translation - %s-mask (0x%x)
> ignores rid-base (0x%x)\n",
> > -				np, 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("%pOF: %s, using mask %08x, rid-base: %08x, out-
> base: %08x, length: %08x, rid: %08x -> %08x\n",
> > -			np, map_name, map_mask, rid_base, out_base,
> > -			rid_len, rid, masked_rid - rid_base + out_base);
> > -		return 0;
> > -	}
> > -
> > -	pr_err("%pOF: Invalid %s translation - no match for rid 0x%x on
> %pOF\n",
> > -		np, map_name, rid, target && *target ? *target : NULL);
> > -	return -EFAULT;
> > -}
> > -
> >   #if IS_ENABLED(CONFIG_OF_IRQ)
> >   /**
> >    * of_irq_parse_pci - Resolve the interrupt for a PCI device diff
> > --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h index
> > 4fa654e..432b53c 100644
> > --- a/include/linux/of_iommu.h
> > +++ b/include/linux/of_iommu.h
> > @@ -15,6 +15,10 @@ extern int of_get_dma_window(struct device_node
> *dn, const char *prefix,
> >   extern const struct iommu_ops *of_iommu_configure(struct device *dev,
> >   					struct device_node *master_np);
> >
> > +int of_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_get_dma_window(struct device_node *dn, const
> > char *prefix, @@ -30,6 +34,13 @@ static inline const struct iommu_ops
> *of_iommu_configure(struct device *dev,
> >   	return NULL;
> >   }
> >
> > +static inline int of_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;
> > +}
> > +
> >   #endif	/* CONFIG_OF_IOMMU */
> >
> >   extern struct of_device_id __iommu_of_table; diff --git
> > a/include/linux/of_pci.h b/include/linux/of_pci.h index
> > 091033a..a23b44a 100644
> > --- a/include/linux/of_pci.h
> > +++ b/include/linux/of_pci.h
> > @@ -17,9 +17,6 @@ struct device_node *of_pci_find_child_device(struct
> device_node *parent,
> >   int of_get_pci_domain_nr(struct device_node *node);
> >   int of_pci_get_max_link_speed(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 struct device_node *of_pci_find_child_device(struct device_node
> *parent,
> >   					     unsigned int devfn)
> > @@ -44,13 +41,6 @@ static inline int of_pci_get_devfn(struct device_node
> *np)
> >   	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 int
> >   of_pci_get_max_link_speed(struct device_node *node)
> >   {
> >