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

[Luis Henriques]

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-3.11.y-queue branch of the 3.11.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-3.11.y-queue

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

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From a9da5c333b493b3544bfeb168b3e1c8496d4295e 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: Luis Henriques <luis.henriques 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 b55c218..3c4b2af 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