[3.8.y.z extended stable] Patch "Revert "of/address: Handle #address-cells > 2 specially"" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    Revert "of/address: Handle #address-cells > 2 specially"

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.16.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From bd68261d3be162ece3062f2f2a74165388a710de Mon Sep 17 00:00:00 2001
From: Rob Herring <robh at kernel.org>
Date: Sun, 29 Dec 2013 19:37:43 -0600
Subject: Revert "of/address: Handle #address-cells > 2 specially"

commit 13fcca8f25f4e9ce7f55da9cd353bb743236e212 upstream.

This reverts commit e38c0a1fbc5803cbacdaac0557c70ac8ca5152e7.

Nikita Yushchenko reports:
While trying to make freescale p2020ds and  mpc8572ds boards working
with mainline kernel, I faced that commit e38c0a1f (Handle

Both these boards have uli1575 chip.
Corresponding part in device tree is something like

                uli1575 at 0 {
                        reg = <0x0 0x0 0x0 0x0 0x0>;
                        #size-cells = <2>;
                        #address-cells = <3>;
                        ranges = <0x2000000 0x0 0x80000000
                                  0x2000000 0x0 0x80000000
                                  0x0 0x20000000

                                  0x1000000 0x0 0x0
                                  0x1000000 0x0 0x0
                                  0x0 0x10000>;
                        isa at 1e {
...

I.e. it has #address-cells = <3>

With commit e38c0a1f reverted, devices under uli1575 are registered
correctly, e.g. for rtc

OF: ** translation for device /pcie at ffe09000/pcie at 0/uli1575 at 0/isa at 1e/rtc at 70 **
OF: bus is isa (na=2, ns=1) on /pcie at ffe09000/pcie at 0/uli1575 at 0/isa at 1e
OF: translating address: 00000001 00000070
OF: parent bus is default (na=3, ns=2) on /pcie at ffe09000/pcie at 0/uli1575 at 0
OF: walking ranges...
OF: ISA map, cp=0, s=1000, da=70
OF: parent translation for: 01000000 00000000 00000000
OF: with offset: 70
OF: one level translation: 00000000 00000000 00000070
OF: parent bus is pci (na=3, ns=2) on /pcie at ffe09000/pcie at 0
OF: walking ranges...
OF: default map, cp=a0000000, s=20000000, da=70
OF: default map, cp=0, s=10000, da=70
OF: parent translation for: 01000000 00000000 00000000
OF: with offset: 70
OF: one level translation: 01000000 00000000 00000070
OF: parent bus is pci (na=3, ns=2) on /pcie at ffe09000
OF: walking ranges...
OF: PCI map, cp=0, s=10000, da=70
OF: parent translation for: 01000000 00000000 00000000
OF: with offset: 70
OF: one level translation: 01000000 00000000 00000070
OF: parent bus is default (na=2, ns=2) on /
OF: walking ranges...
OF: PCI map, cp=0, s=10000, da=70
OF: parent translation for: 00000000 ffc10000
OF: with offset: 70
OF: one level translation: 00000000 ffc10070
OF: reached root node

With commit e38c0a1f in place, address translation fails:

OF: ** translation for device /pcie at ffe09000/pcie at 0/uli1575 at 0/isa at 1e/rtc at 70 **
OF: bus is isa (na=2, ns=1) on /pcie at ffe09000/pcie at 0/uli1575 at 0/isa at 1e
OF: translating address: 00000001 00000070
OF: parent bus is default (na=3, ns=2) on /pcie at ffe09000/pcie at 0/uli1575 at 0
OF: walking ranges...
OF: ISA map, cp=0, s=1000, da=70
OF: parent translation for: 01000000 00000000 00000000
OF: with offset: 70
OF: one level translation: 00000000 00000000 00000070
OF: parent bus is pci (na=3, ns=2) on /pcie at ffe09000/pcie at 0
OF: walking ranges...
OF: default map, cp=a0000000, s=20000000, da=70
OF: default map, cp=0, s=10000, da=70
OF: not found !

Thierry Reding confirmed this commit was not needed after all:
"We ended up merging a different address representation for Tegra PCIe
and I've confirmed that reverting this commit doesn't cause any obvious
regressions. I think all other drivers in drivers/pci/host ended up
copying what we did on Tegra, so I wouldn't expect any other breakage
either."

There doesn't appear to be a simple way to support both behaviours, so
reverting this as nothing should be depending on the new behaviour.

Signed-off-by: Rob Herring <robh at kernel.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/of/address.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 0125524..fb2a4e8 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -69,14 +69,6 @@ static u64 of_bus_default_map(__be32 *addr, const __be32 *range,
 		 (unsigned long long)cp, (unsigned long long)s,
 		 (unsigned long long)da);

-	/*
-	 * If the number of address cells is larger than 2 we assume the
-	 * mapping doesn't specify a physical address. Rather, the address
-	 * specifies an identifier that must match exactly.
-	 */
-	if (na > 2 && memcmp(range, addr, na * 4) != 0)
-		return OF_BAD_ADDR;
-
 	if (da < cp || da >= (cp + s))
 		return OF_BAD_ADDR;
 	return da - cp;
--
1.8.3.2