PCI: designware: Program ATU with untranslated address
authorKishon Vijay Abraham I <kishon@ti.com>
Thu, 17 Jul 2014 09:00:41 +0000 (14:30 +0530)
committerBjorn Helgaas <bhelgaas@google.com>
Tue, 22 Jul 2014 21:26:24 +0000 (15:26 -0600)
commitf4c55c5a3f7f68c06cc559ed7af8b2d017cbb0a7
tree5ee2b55f134ff11382ce97459d1291939b645aa2
parent4dd964df36d0e548e1806ec2ec275b62d4dc46e8
PCI: designware: Program ATU with untranslated address

In DRA7, the CPU sees 32-bit addresses, but the PCIe controller can see
only 28-bit addresses.  So whenever the CPU issues a read/write request,
the 4 most significant bits are used by L3 to determine the target
controller.  For example, the CPU reserves [mem 0x20000000-0x2fffffff]
for the PCIe controller but the PCIe controller will see only
[0x00000000-0x0fffffff].  For programming the outbound translation
window the *base* should be programmed as 0x00000000.  Whenever we try to
write to, e.g., 0x20000000, it will be translated to whatever we have
programmed in the translation window with base as 0x00000000.

This is needed when the dt node is modelled something like this:

    axi {
        compatible = "simple-bus";
        #size-cells = <1>;
        #address-cells = <1>;
        ranges = <0x0        0x20000000 0x10000000 // 28-bit bus
                  0x51000000 0x51000000 0x3000>;
        pcie@51000000 {
                reg = <0x1000 0x2000>, <0x51002000 0x14c>, <0x51000000 0x2000>;
                reg-names = "config", "ti_conf", "rc_dbics";
                #address-cells = <3>;
                #size-cells = <2>;
                ranges = <0x81000000 0 0          0x03000 0 0x00010000
                          0x82000000 0 0x20013000 0x13000 0 0xffed000>;
        };
    };

Here the CPU address for configuration space is 0x20013000 and the
controller address for configuration space is 0x13000.  The controller
address should be used while programming the ATU (in order for translation
to happen properly in DRA7xx).

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mohit Kumar <mohit.kumar@st.com>
Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Arnd Bergmann <arnd@arndb.de>
drivers/pci/host/pcie-designware.c
drivers/pci/host/pcie-designware.h