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Date: Wed, 23 Sep 2015 10:12:39 -0700
From: David Daney <ddaney@...iumnetworks.com>
To: Rob Herring <robh@...nel.org>
CC: David Daney <ddaney.cavm@...il.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Will Deacon <will.deacon@....com>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
Marc Zyngier <marc.zyngier@....com>,
Grant Likely <grant.likely@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
Jason Cooper <jason@...edaemon.net>,
David Daney <david.daney@...ium.com>,
Frank Rowand <frowand.list@...il.com>
Subject: Re: [PATCH v2 2/3] of/irq: Add new function of_msi_map_rid()
On 09/23/2015 10:07 AM, Rob Herring wrote:
> On Tue, Sep 22, 2015 at 7:00 PM, David Daney <ddaney.cavm@...il.com> wrote:
>> From: David Daney <david.daney@...ium.com>
>>
>> The device tree property "msi-map" specifies how to create the PCI
>> requester id used in some MSI controllers. Add a new function
>> of_msi_map_rid() that finds the msi-map property and applies its
>> translation to a given requester id.
>>
>> Signed-off-by: David Daney <david.daney@...ium.com>
>> ---
>> drivers/of/irq.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++
>> include/linux/of_irq.h | 7 ++++
>> 2 files changed, 93 insertions(+)
>>
>> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
>> index 55317fa..3f64d2e 100644
>> --- a/drivers/of/irq.c
>> +++ b/drivers/of/irq.c
>> @@ -598,3 +598,89 @@ void of_msi_configure(struct device *dev, struct device_node *np)
>> d = irq_find_host(msi_np);
>> dev_set_msi_domain(dev, d);
>> }
>> +
>> +/**
>> + * of_msi_map_rid - Map a MSI requester ID for a device.
>> + * @dev: device for which the mapping is to be done.
>> + * @msi_np: device node of the expected msi controller.
>> + * @rid_in: unmapped MSI requester ID for the device.
>> + *
>> + * Walk up the device hierarchy looking for devices with a "msi-map"
>> + * property. If found, apply the mapping to @rid_in.
>> + *
>> + * Returns the mapped MSI requester ID.
>> + */
>> +u32 of_msi_map_rid(struct device *dev, struct device_node *msi_np, u32 rid_in)
>
> Generally, the OF API does not use struct device except for what is in
> of/device.c. I'm guessing you need it here because you have devices
> without DT nodes?
Exactly right. As you can see we walk up the hierarchy until we find a
device with the desired of_node ("msi-map").
>
> We may want to handle this more like NUMA node IDs where we populate
> data in struct device at creation time and looking at struct device
> parents is independent of DT. How would this information be retrieved
> with ACPI?
ACPI has a table called _IORT that contains similar information. It
would have to be extracted with an analogous facility.
>
>> +{
>> + struct device *parent_dev;
>> + struct device_node *msi_controller_node;
>> + const __be32 *msi_map;
>
>> + u32 map_mask, masked_rid;
>> + u32 rid_base, msi_base, rid_len, phandle;
>
> One line please.
OK.
It looks like another revision of the patch is in order.
>
>> + int msi_map_len;
>> + bool matched;
>> + u32 rid_out = rid_in;
>> +
>> + /*
>> + * Walk up the device parent links looking for one with a
>> + * "msi-map" property.
>> + */
>> + msi_map = NULL;
>
> init in the declaration.
OK...
>
>> + 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);
>> + goto out;
>
> Just return here.
>
>> + }
>> + /* We have a good parent_dev and msi_map, let's use them. */
>> + break;
>> + }
>> + if (!msi_map)
>> + goto out;
>
> Just return here.
>
>> +
>> + /* 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);
>> +
>> + msi_controller_node = of_find_node_by_phandle(phandle);
>> +
>> + matched = masked_rid >= rid_base &&
>> + masked_rid < rid_base + rid_len &&
>> + msi_np == msi_controller_node;
>> +
>> + of_node_put(msi_controller_node);
>> + msi_map_len -= 4 * sizeof(__be32);
>> + msi_map += 4;
>> + }
>> + if (!matched)
>> + goto out;
>
> Just return here.
>
>> +
>> + rid_out = masked_rid + 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);
>> +out:
>> + return rid_out;
>> +}
>> diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
>> index 4bcbd58..8cd9334 100644
>> --- a/include/linux/of_irq.h
>> +++ b/include/linux/of_irq.h
>> @@ -75,6 +75,7 @@ static inline int of_irq_to_resource_table(struct device_node *dev,
>> extern unsigned int irq_of_parse_and_map(struct device_node *node, int index);
>> extern struct device_node *of_irq_find_parent(struct device_node *child);
>> extern void of_msi_configure(struct device *dev, struct device_node *np);
>> +u32 of_msi_map_rid(struct device *dev, struct device_node *msi_np, u32 rid_in);
>>
>> #else /* !CONFIG_OF */
>> static inline unsigned int irq_of_parse_and_map(struct device_node *dev,
>> @@ -87,6 +88,12 @@ static inline void *of_irq_find_parent(struct device_node *child)
>> {
>> return NULL;
>> }
>> +
>> +static inline u32 of_msi_map_rid(struct device *dev,
>> + struct device_node *msi_np, u32 rid_in)
>> +{
>> + return rid_in;
>> +}
>> #endif /* !CONFIG_OF */
>>
>> #endif /* __OF_IRQ_H */
>> --
>> 1.9.1
>>
--
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