[RFC 4/9] of/irq: Refactor interrupt-map parsing

Grant Likely
2013-10-15T20:39:41Z

All the users of of_irq_parse_raw pass in a raw interrupt specifier from
the device tree and expect it to be returned (possibly modified) in an
of_phandle_args structure. However, the primary function of
of_irq_parse_raw() is to check for translations due to the presence of
one or more interrupt-map properties. The actual placing of the data
into an of_phandle_args structure is trivial. If it is refactored to
accept an of_phandle_args structure directly, then it becomes possible
to consume of_phandle_args from other sources. This is important for an
upcoming patch that allows a device to be connected to more than one
interrupt parent. It also simplifies the code a bit.

The biggest complication with this patch is that the old version works
on the interrupt specifiers in __be32 form, but the of_phandle_args
structure is intended to carry it in the cpu-native version. A bit of
churn was required to make this work. In the end it results in tighter
code, so the churn is worth it.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/platforms/fsl_uli1575.c | 6 +-
drivers/of/irq.c | 108 ++++++++++++++++++-----------------
drivers/of/of_pci_irq.c | 7 ++-
include/linux/of_irq.h | 5 +-
4 files changed, 67 insertions(+), 59 deletions(-)

diff --git a/arch/powerpc/platforms/fsl_uli1575.c b/arch/powerpc/platforms/fsl_uli1575.c
index 8904046..b97f6f3 100644
--- a/arch/powerpc/platforms/fsl_uli1575.c
+++ b/arch/powerpc/platforms/fsl_uli1575.c
@@ -322,7 +322,6 @@ static void hpcd_final_uli5288(struct pci_dev *dev)
struct pci_controller *hose = pci_bus_to_host(dev->bus);
struct device_node *hosenode = hose ? hose->dn : NULL;
struct of_phandle_args oirq;
- int pin = 2;
u32 laddr[3];

if (!machine_is(mpc86xx_hpcd))
@@ -331,9 +330,12 @@ static void hpcd_final_uli5288(struct pci_dev *dev)
if (!hosenode)
return;

+ oirq.np = hosenode;
+ oirq.args[0] = 2;
+ oirq.args_count = 1;
laddr[0] = (hose->first_busno << 16) | (PCI_DEVFN(31, 0) << 8);
laddr[1] = laddr[2] = 0;
- of_irq_parse_raw(hosenode, &pin, 1, laddr, &oirq);
+ of_irq_parse_raw(laddr, &oirq);
dev->irq = irq_create_of_mapping(&oirq);
}

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 84184c4..0ed5ed4 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -80,31 +80,32 @@ struct device_node *of_irq_find_parent(struct device_node *child)
/**
* of_irq_parse_raw - Low level interrupt tree parsing
* @parent: the device interrupt parent
- * @intspec: interrupt specifier ("interrupts" property of the device)
- * @ointsize: size of the passed in interrupt specifier
- * @addr: address specifier (start of "reg" property of the device)
- * @out_irq: structure of_irq filled by this function
+ * @addr: address specifier (start of "reg" property of the device) in be32 format
+ * @out_irq: structure of_irq updated by this function
*
* Returns 0 on success and a negative number on error
*
* This function is a low-level interrupt tree walking function. It
* can be used to do a partial walk with synthetized reg and interrupts
* properties, for example when resolving PCI interrupts when no device
- * node exist for the parent.
+ * node exist for the parent. It takes an interrupt specifier structure as
+ * input, walks the tree looking for any interrupt-map properties, translates
+ * the specifier for each map, and then returns the translated map.
*/
-int of_irq_parse_raw(struct device_node *parent, const __be32 *intspec,
- u32 ointsize, const __be32 *addr, struct of_phandle_args *out_irq)
+int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
{
struct device_node *ipar, *tnode, *old = NULL, *newpar = NULL;
- const __be32 *tmp, *imap, *imask;
+ __be32 initial_match_array[8];
+ const __be32 *match_array = initial_match_array;
+ const __be32 *tmp, *imap, *imask, dummy_imask[] = { ~0, ~0, ~0, ~0, ~0 };
u32 intsize = 1, addrsize, newintsize = 0, newaddrsize = 0;
int imaplen, match, i;

pr_debug("of_irq_parse_raw: par=%s,intspec=[0x%08x 0x%08x...],ointsize=%d\n",
- of_node_full_name(parent), be32_to_cpup(intspec),
- be32_to_cpup(intspec + 1), ointsize);
+ of_node_full_name(out_irq->np), out_irq->args[0], out_irq->args[1],
+ out_irq->args_count);

- ipar = of_node_get(parent);
+ ipar = of_node_get(out_irq->np);

/* First get the #interrupt-cells property of the current cursor
* that tells us how to interpret the passed-in intspec. If there
@@ -127,7 +128,7 @@ int of_irq_parse_raw(struct device_node *parent, const __be32 *intspec,

pr_debug("of_irq_parse_raw: ipar=%s, size=%d\n", of_node_full_name(ipar), intsize);

- if (ointsize != intsize)
+ if (out_irq->args_count != intsize)
return -EINVAL;

/* Look for this #address-cells. We have to implement the old linux
@@ -146,6 +147,21 @@ int of_irq_parse_raw(struct device_node *parent, const __be32 *intspec,

pr_debug(" -> addrsize=%d\n", addrsize);

+ /* If we were passed no "reg" property and we attempt to parse
+ * an interrupt-map, then #address-cells must be 0.
+ * Fail if it's not.
+ */
+ if (addr == NULL && addrsize != 0) {
+ pr_debug(" -> no reg passed in when needed !\n");
+ return -EINVAL;
+ }
+
+ /* Precalculate the match array - this simplifies match loop */
+ for (i = 0; i < addrsize; i++)
+ initial_match_array[i] = addr[i];
+ for (i = 0; i < intsize; i++)
+ initial_match_array[addrsize + i] = cpu_to_be32(out_irq->args[i]);
+
/* Now start the actual "proper" walk of the interrupt tree */
while (ipar != NULL) {
/* Now check if cursor is an interrupt-controller and if it is
@@ -154,11 +170,6 @@ int of_irq_parse_raw(struct device_node *parent, const __be32 *intspec,
if (of_get_property(ipar, "interrupt-controller", NULL) !=
NULL) {
pr_debug(" -> got it !\n");
- for (i = 0; i < intsize; i++)
- out_irq->args[i] =
- of_read_number(intspec +i, 1);
- out_irq->args_count = intsize;
- out_irq->np = ipar;
of_node_put(old);
return 0;
}
@@ -175,34 +186,16 @@ int of_irq_parse_raw(struct device_node *parent, const __be32 *intspec,

/* Look for a mask */
imask = of_get_property(ipar, "interrupt-map-mask", NULL);
-
- /* If we were passed no "reg" property and we attempt to parse
- * an interrupt-map, then #address-cells must be 0.
- * Fail if it's not.
- */
- if (addr == NULL && addrsize != 0) {
- pr_debug(" -> no reg passed in when needed !\n");
- goto fail;
- }
+ if (!imask)
+ imask = dummy_imask;

/* Parse interrupt-map */
match = 0;
while (imaplen > (addrsize + intsize + 1) && !match) {
/* Compare specifiers */
match = 1;
- for (i = 0; i < addrsize && match; ++i) {
- __be32 mask = imask ? imask[i]
- : cpu_to_be32(0xffffffffu);
- match = ((addr[i] ^ imap[i]) & mask) == 0;
- }
- for (; i < (addrsize + intsize) && match; ++i) {
- __be32 mask = imask ? imask[i]
- : cpu_to_be32(0xffffffffu);
- match =
- ((intspec[i-addrsize] ^ imap[i]) & mask) == 0;
- }
- imap += addrsize + intsize;
- imaplen -= addrsize + intsize;
+ for (i = 0; i < (addrsize + intsize); i++, imaplen--)
+ match = !((match_array[i] ^ *imap++) & imask[i]);

pr_debug(" -> match=%d (imaplen=%d)\n", match, imaplen);

@@ -247,12 +240,18 @@ int of_irq_parse_raw(struct device_node *parent, const __be32 *intspec,
if (!match)
goto fail;

- of_node_put(old);
- old = of_node_get(newpar);
+ /*
+ * Successfully parsed an interrrupt-map translation; copy new
+ * interrupt specifier into the out_irq structure
+ */
+ of_node_put(out_irq->np);
+ out_irq->np = of_node_get(newpar);
+
+ match_array = imap - newaddrsize - newintsize;
+ for (i = 0; i < newintsize; i++)
+ out_irq->args[i] = be32_to_cpup(imap - newintsize + i);
+ out_irq->args_count = intsize = newintsize;
addrsize = newaddrsize;
- intsize = newintsize;
- intspec = imap - intsize;
- addr = intspec - addrsize;

skiplevel:
/* Iterate again with new parent */
@@ -263,7 +262,7 @@ int of_irq_parse_raw(struct device_node *parent, const __be32 *intspec,
}
fail:
of_node_put(ipar);
- of_node_put(old);
+ of_node_put(out_irq->np);
of_node_put(newpar);

return -EINVAL;
@@ -276,15 +275,16 @@ EXPORT_SYMBOL_GPL(of_irq_parse_raw);
* @index: index of the interrupt to resolve
* @out_irq: structure of_irq filled by this function
*
- * This function resolves an interrupt, walking the tree, for a given
- * device-tree node. It's the high level pendant to of_irq_parse_raw().
+ * This function resolves an interrupt for a node by walking the interrupt tree,
+ * finding which interrupt controller node it is attached to, and returning the
+ * interrupt specifier that can be used to retrieve a Linux IRQ number.
*/
int of_irq_parse_one(struct device_node *device, int index, struct of_phandle_args *out_irq)
{
struct device_node *p;
const __be32 *intspec, *tmp, *addr;
u32 intsize, intlen;
- int res = -EINVAL;
+ int i, res = -EINVAL;

pr_debug("of_irq_parse_one: dev=%s, index=%d\n", of_node_full_name(device), index);

@@ -320,9 +320,15 @@ int of_irq_parse_one(struct device_node *device, int index, struct of_phandle_ar
if ((index + 1) * intsize > intlen)
goto out;

- /* Get new specifier and map it */
- res = of_irq_parse_raw(p, intspec + index * intsize, intsize,
- addr, out_irq);
+ /* Copy intspec into irq structure */
+ intspec += index * intsize;
+ out_irq->np = p;
+ out_irq->args_count = intsize;
+ for (i = 0; i < intsize; i++)
+ out_irq->args[i] = be32_to_cpup(intspec++);
+
+ /* Check if there are any interrupt-map translations to process */
+ res = of_irq_parse_raw(addr, out_irq);
out:
of_node_put(p);
return res;
diff --git a/drivers/of/of_pci_irq.c b/drivers/of/of_pci_irq.c
index ee3293d..303afeb 100644
--- a/drivers/of/of_pci_irq.c
+++ b/drivers/of/of_pci_irq.c
@@ -85,9 +85,12 @@ int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq
pdev = ppdev;
}

+ out_irq->np = ppnode;
+ out_irq->args_count = 1;
+ out_irq->args[0] = lspec;
lspec_be = cpu_to_be32(lspec);
laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
- laddr[1] = laddr[2] = cpu_to_be32(0);
- return of_irq_parse_raw(ppnode, &lspec_be, 1, laddr, out_irq);
+ laddr[1] = laddr[2] = cpu_to_be32(0);
+ return of_irq_parse_raw(laddr, out_irq);
}
EXPORT_SYMBOL_GPL(of_irq_parse_pci);
diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
index 3bbba8d..c0d6dfe 100644
--- a/include/linux/of_irq.h
+++ b/include/linux/of_irq.h
@@ -31,10 +31,7 @@ static inline int of_irq_parse_oldworld(struct device_node *device, int index,
}
#endif /* CONFIG_PPC32 && CONFIG_PPC_PMAC */

-
-extern int of_irq_parse_raw(struct device_node *parent, const __be32 *intspec,
- u32 ointsize, const __be32 *addr,
- struct of_phandle_args *out_irq);
+extern int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq);
extern int of_irq_parse_one(struct device_node *device, int index,
struct of_phandle_args *out_irq);
extern unsigned int irq_create_of_mapping(struct of_phandle_args *irq_data);
--
1.8.1.2