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Message-ID: <20150923175216.3384d7b4@arm.com>
Date: Wed, 23 Sep 2015 17:52:16 +0100
From: Marc Zyngier <marc.zyngier@....com>
To: David Daney <ddaney.cavm@...il.com>
Cc: <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>,
<devicetree@...r.kernel.org>,
"Grant Likely" <grant.likely@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
"Jason Cooper" <jason@...edaemon.net>,
David Daney <david.daney@...ium.com>
Subject: Re: [PATCH v2 2/3] of/irq: Add new function of_msi_map_rid()
On Tue, 22 Sep 2015 17:00:05 -0700
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)
> +{
> + 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;
> + 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;
> + 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;
> + }
> + /* We have a good parent_dev and msi_map, let's use them. */
> + break;
> + }
> + if (!msi_map)
> + goto 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);
Rob did suggest to use of_property_read_u32_index() instead of these
be32_to_cpup(). Not sure if that'd be a major improvement though.
> +
> + 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;
> +
> + 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 */
Otherwise looks good to me.
Reviewed-by: Marc Zyngier <marc.zyngier@....com>
M.
--
Jazz is not dead. It just smells funny.
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