Re: commit e38c0a1f breaks powerpc boards with uli1575 chip

[fixed DT maillist address]

On 12/17/2013 01:35 AM, Nikita Yushchenko wrote:

Hi

While trying to make freescale p2020ds and  mpc8572ds boards working with mainline kernel, I faced that commit 
e38c0a1f (Handle #address-cells > 2 specially) breaks things with these boards.

Good to see this broke in v3.7 and is just now found...

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

                uli1575@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@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@ffe09000/pcie@0/uli1575@0/isa@1e/rtc@70 **
OF: bus is isa (na=2, ns=1) on /pcie@ffe09000/pcie@0/uli1575@0/isa@1e
OF: translating address: 00000001 00000070
OF: parent bus is default (na=3, ns=2) on /pcie@ffe09000/pcie@0/uli1575@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@ffe09000/pcie@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@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@ffe09000/pcie@0/uli1575@0/isa@1e/rtc@70 **
OF: bus is isa (na=2, ns=1) on /pcie@ffe09000/pcie@0/uli1575@0/isa@1e
OF: translating address: 00000001 00000070
OF: parent bus is default (na=3, ns=2) on /pcie@ffe09000/pcie@0/uli1575@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@ffe09000/pcie@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 !

Either e38c0a1f should be reverted, or uli1575 (and perhaps other similar devices) have to be described in device 
trees differently.

Reverting would break Tegra PCIe, but you should not have to change the
DT either. So we need a solution.

Is this something like this sufficient to fix it?

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 4b9317b..378aebd 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c

@@ -74,7 +74,7 @@ static u64 of_bus_default_map(__be32 *addr, const

__be32 *range,
         * 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)
+       if (na > 2 && memcmp(range, addr, (na - 2) * 4) != 0)
                return OF_BAD_ADDR;

        if (da < cp || da >= (cp + s))