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of: Fix comparison of "compatible" properties

PATCH In review Grant Likely 4 participants 4 messages Mar 18, 2010 1 message not in the archive Device tree

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#0 lore raw

PATCH 1/1 of: Fix comparison of "compatible" properties

Commit 7c7b60cb87547b1664a4385c187f029bf514a737
"of: put default string compare and #a/s-cell values into common header"

Breaks various things on powerpc due to using strncasecmp instead of strcasecmp for comparing against "compatible" strings.

This causes things like the 4xx PCI code to fail miserably due to the partial matches in code like this:

for_each_compatible_node(np, NULL, "ibm,plb-pcix")
ppc4xx_probe_pcix_bridge(np);
for_each_compatible_node(np, NULL, "ibm,plb-pci")
ppc4xx_probe_pci_bridge(np);

This reverts us to use strcasecmp. I do wonder why microblase and sparc want the partial matches though. For sparc it could be historical, but microblaze is probably doing the wrong thing so this patch also changes the microblaze behaviour to use not allow partial matches. Michal will surely beat me over the head with a cluestick if I'm wrong, in which case I'll fix this patch.

It's not quite right to do partial name match. Entries in a compatible list are meant to be matched whole. If a device is compatible with both "foo" and "foo1", then the device should have both strings in its "compatible" property.

(for patch description)

CC David Miller <davem-fT/PcQaiUtIeIZ0/[email protected]>
CC devicetree-discuss-uLR06cmDAlY/[email protected]
CC Michal Simek <[email protected]>

---

 include/linux/of.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
include/linux/of.h +1 -1
index f6d9cbc..a367e19 100644
@@ -127,7 +127,7 @@ static inline unsigned long of_read_ulong(const __be32 *cell, int size)
 
 /* Default string compare functions, Allow arch asm/prom.h to override */
 #if !defined(of_compat_cmp)
-#define of_compat_cmp(s1, s2, l)	strncasecmp((s1), (s2), (l))
+#define of_compat_cmp(s1, s2, l)	strcasecmp((s1), (s2))
 #define of_prop_cmp(s1, s2)		strcmp((s1), (s2))
 #define of_node_cmp(s1, s2)		strcasecmp((s1), (s2))
 #endif
Acked-by on v1 1/1
#1 lore raw

From: Grant Likely <grant.likely-s3s/[email protected]>
Date: Wed, 17 Mar 2010 19:01:00 -0600

Quoted 21 lines

Commit 7c7b60cb87547b1664a4385c187f029bf514a737
"of: put default string compare and #a/s-cell values into common header"

Breaks various things on powerpc due to using strncasecmp instead of strcasecmp for comparing against "compatible" strings.

This causes things like the 4xx PCI code to fail miserably due to the partial matches in code like this:

for_each_compatible_node(np, NULL, "ibm,plb-pcix")
ppc4xx_probe_pcix_bridge(np);
for_each_compatible_node(np, NULL, "ibm,plb-pci")
ppc4xx_probe_pci_bridge(np);

This reverts us to use strcasecmp. I do wonder why microblase and sparc want the partial matches though. For sparc it could be historical, but microblaze is probably doing the wrong thing so this patch also changes the microblaze behaviour to use not allow partial matches. Michal will surely beat me over the head with a cluestick if I'm wrong, in which case I'll fix this patch.

Quoted 8 lines

It's not quite right to do partial name match. Entries in a compatible list are meant to be matched whole. If a device is compatible with both "foo" and "foo1", then the device should have both strings in its "compatible" property.

(for patch description)

A message that is not in the archive (sent off-list or not yet received): 20100317.231847.112586488.davem-fT/PcQaiUtIeIZ0/[email protected]

#3 lore raw
Quoted 4 lines · David Miller
Quoted 1 line

It's not quite right to do partial name match. Entries in a

compatible

Quoted 1 line

list are meant to be matched whole. If a device is compatible with

both

Quoted 8 lines
Quoted 6 lines

"foo" and "foo1", then the device should have both strings in its "compatible" property.

(for patch description)

BTW. While at it... sparc still has it's override here to do partial match (strncmp iirc). Do you rely on it ? Or do you do that only to be case insensitive and the "n" is a result of history ?

Cheers,
Ben

Acked-by on v1 1/1
#4 lore raw
In reply to Grant Likely
Quoted 14 lines · Grant Likely

Commit 7c7b60cb87547b1664a4385c187f029bf514a737
"of: put default string compare and #a/s-cell values into common header"

Breaks various things on powerpc due to using strncasecmp instead of strcasecmp for comparing against "compatible" strings.

This causes things like the 4xx PCI code to fail miserably due to the partial matches in code like this:

for_each_compatible_node(np, NULL, "ibm,plb-pcix")
ppc4xx_probe_pcix_bridge(np);
for_each_compatible_node(np, NULL, "ibm,plb-pci")
ppc4xx_probe_pci_bridge(np);

Quoted 6 lines

This reverts us to use strcasecmp. I do wonder why microblase and sparc want the partial matches though. For sparc it could be historical, but microblaze is probably doing the wrong thing so this patch also changes the microblaze behaviour to use not allow partial matches. Michal will surely beat me over the head with a cluestick if I'm wrong, in which case I'll fix this patch.

No, you are correct. I don't want partial matches.

Quoted 5 lines

It's not quite right to do partial name match. Entries in a compatible list are meant to be matched whole. If a device is compatible with both "foo" and "foo1", then the device should have both strings in its "compatible" property.

Nice example. I have better one. Look at of_serial.c. ns16550a must be for partial matches before ns16550. :-)

	{ .type = "serial", .compatible = "ns16550a", .data = (void 
*)PORT_16550A, },
	{ .type = "serial", .compatible = "ns16550",  .data = (void 

*)PORT_16550, },

Quoted 26 lines

(for patch description)

CC David Miller <davem-fT/PcQaiUtIeIZ0/[email protected]>
CC devicetree-discuss-uLR06cmDAlY/[email protected]
CC Michal Simek <[email protected]>

---

 include/linux/of.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
include/linux/of.h +1 -1
index f6d9cbc..a367e19 100644
@@ -127,7 +127,7 @@ static inline unsigned long of_read_ulong(const __be32 *cell, int size)
 
 /* Default string compare functions, Allow arch asm/prom.h to override */
 #if !defined(of_compat_cmp)
-#define of_compat_cmp(s1, s2, l)	strncasecmp((s1), (s2), (l))
+#define of_compat_cmp(s1, s2, l)	strcasecmp((s1), (s2))
 #define of_prop_cmp(s1, s2)		strcmp((s1), (s2))
 #define of_node_cmp(s1, s2)		strcasecmp((s1), (s2))
 #endif
Signature · 4 lines
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian