Hi Boris,

  Thank you very much for the prompt review and suggestions...

On 4/5/2020 3:08 pm, Boris Brezillon wrote:
On Mon, 4 May 2020 10:02:35 +0800
"Ramuthevar, Vadivel MuruganX"
<vadivel.muruganx.ramuthe...@linux.intel.com>  wrote:

Hi Boris,

On 30/4/2020 9:01 pm, Boris Brezillon wrote:
On Thu, 30 Apr 2020 14:36:00 +0200
Boris Brezillon<boris.brezil...@collabora.com>  wrote:
On Thu, 30 Apr 2020 17:07:03 +0800
"Ramuthevar, Vadivel MuruganX"
<vadivel.muruganx.ramuthe...@linux.intel.com>  wrote:
The question is, is it the same value we have in nand_pa or it is
different?
Different address which is 0xE1400000 NAND_BASE_PHY address.
Then why didn't you tell me they didn't match when I suggested to pass
sorry, because you keep asking nand_pa after that only I realized that.
nand_pa? So now the question is, what does this address represent?
                  EBU-MODULE
    _________     _______________________
|         |   |            |NAND CTRL  |
| FPI BUS |==>| CS0(0x174) | 0xE100    ( 0xE14/0xE1C) NAND_PHY_BASE
|_________|   |_CS1(0x17C)_|__________ |

EBU_CONRTROLLER_BASE : 0xE0F0_0000
HSNAND_BASE: 0xE100_0000
NAND_CS0: 0xE140_0000
NAND_CS1: 0xE1C0_0000

MEM_REGION_BASE_CS0: 0x17400 (internal to ebu controller )
MEM_REGION_BASE_CS1: 0x17C00
Hm, I wonder if we shouldn't use a 'ranges' property to describe this
address translation. Something like

        ebu@xxx {
                ranges = <0x17400000 0xe1400000 0x1000>,
                         <0x17c00000 0xe1c00000 0x1000>;
                reg = <0x17400000>, <0x17c00000>;
                reg-names = "cs-0", "cs-1";
        }

The translated address (0xE1X00000) will be available in res->start,
and the non-translated one (0x17X00000) can be retrieved with
of_get_address(). All you'd have to do then would be calculate the
mask:

        mask = (translated_address & original_address) >> 22;
        num_comp_bits = fls(mask);
        WARN_ON(mask != GENMASK(num_comp_bits - 1, 0));

Which allows you to properly set the ADDR_SEL() register without
relying on some hardcoded values:

        writel(original_address | EBU_ADDR_SEL_REGEN |
               EBU_ADDR_COMP_BITS(num_comp_bits),
               ebu_host->ebu + EBU_ADDR_SEL(csid));

That's quite important if we want to merge the xway NAND driver with
this one.
Looks like the translation is done at the FPI bus declaration level (see
[1]). We really need to see the big picture to take a wise decision
about the bindings. Would you mind pasting your dsti/dts files
somewhere? It feels like the NAND controller is a sub-part of a more
generic 'memory' controller, in which case the NAND controller should be
declared as a child of this generic memory bus (called localbus in [1],
but maybe EBU is more accurate).

[1]https://github.com/xieyaxiongfly/Atheros_CSI_tool_OpenWRT_src/blob/master/target/linux/lantiq/files-4.14/arch/mips/boot/dts/vr9.dtsi#L162

   ebu_nand: ebu_nand@e0f00000 {
                   compatible = "intel,lgm-ebu-nand";
                   reg = <0xe0f00000 0x100
                   0xe1000000 0x300
                   0xe1400000 0x80000
                   0xe1c00000 0x10000>;
                   reg-names = "ebunand", "hsnand", "nand_cs0", nand_cs1";
                   dmas = <&dma0 8>, <&dma0 9>;
                   dma-names = "ebu_rx", "ebu_tx";
                   clocks =  <&cgu0 LGM_GCLK_EBU>;
           };


         &ebu_nand {
                 status = "disabled";
                nand,cs = <1>;
                nand-ecc-mode = "hw";
                pinctrl-names = "default";
                pinctrl-0 = <&ebu_nand_base &ebu_cs1>;
        };

Ok. If I understand the SoC topology correctly it should actually be
something like that:

{
        ...
        fpi@xxxxx {
                compatible = "intel,lgm-fpi", "simple-bus";

                /* You might have other ranges to define here */
                ranges = <0x16000000 0xe0000000 0x1000000>;

                ...

Sorry, we do not have fpi tree node in our dts/dtsi file instead we have the below one.. , that also not included the major peripherals controllers node.
        /* Special part from CPU core */
        core: core {
                compatible = "intel,core", "simple-bus";
                #address-cells = <1>;
                #size-cells = <1>;
                ranges;

                ioapic1: interrupt-controller@fec00000 {
                        #interrupt-cells = <2>;
                        #address-cells = <0>;
                        compatible = "intel,ce4100-ioapic";
                        interrupt-controller;
                        reg = <0xfec00000 0x1000>;
                        nr_entries = <256>;
                };

                hpet: timer@fed00000 {
                        compatible = "intel,ce4100-hpet";
                        reg = <0xfed00000 0x400>;
                };

                lapic0: interrupt-controller@fee00000 {
                        compatible = "intel,ce4100-lapic";
                        reg = <0xfee00000 0x1000>;
                        no_pic_mode;
                };
        };

other than this, rest all in independent node .

Thanks!

Regards
Vadivel

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