Re: [PATCH 2/3] dt-bindings: arm: amlogic: Add SoC information bindings

[Neil Armstrong]

On 04/03/2017 06:34 PM, Rob Herring wrote:
> On Fri, Mar 31, 2017 at 04:10:30PM +0200, Neil Armstrong wrote:
>> On 03/31/2017 03:44 PM, Arnd Bergmann wrote:
>>> On Fri, Mar 31, 2017 at 10:47 AM, Neil Armstrong
>>> <narmstrong@xxxxxxxxxxxx> wrote:
>>>> Add bindings for the SoC information register of the Amlogic SoCs.
>>>>
>>>> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>>>> ---
>>>>  Documentation/devicetree/bindings/arm/amlogic.txt | 20 ++++++++++++++++++++
>>>>  1 file changed, 20 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/arm/amlogic.txt b/Documentation/devicetree/bindings/arm/amlogic.txt
>>>> index bfd5b55..b850985 100644
>>>> --- a/Documentation/devicetree/bindings/arm/amlogic.txt
>>>> +++ b/Documentation/devicetree/bindings/arm/amlogic.txt
>>>> @@ -52,3 +52,23 @@ Board compatible values:
>>>>    - "amlogic,q201" (Meson gxm s912)
>>>>    - "nexbox,a95x" (Meson gxbb or Meson gxl s905x)
>>>>    - "nexbox,a1" (Meson gxm s912)
>>>> +
>>>> +Amlogic Meson GX SoCs Information
>>>> +----------------------------------
>>>> +
>>>> +The Meson SoCs have a Product Register that allows to retrieve SoC type,
>>>> +package and revision information. If present, a device node for this register
>>>> +should be added.
>>>> +
>>>> +Required properties:
>>>> +  - compatible: For Meson GX SoCs, must be "amlogic,meson-gx-socinfo".
>>>> +  - reg: Base address and length of the register block.
>>>> +
>>>> +Examples
>>>> +--------
>>>> +
>>>> +       chipid@220 {
>>>> +               compatible = "amlogic,meson-gx-socinfo";
>>>> +               reg = <0x0 0x00220 0x0 0x4>;
>>>> +       };
>>>> +
>>>
>>> The register location would hint that this is in the middle of some block of
>>> random registers, i.e. a syscon or some unrelated device.
>>>
>>> Are you sure that "socinfo" is the actual name of the IP block and that
>>> it only has a single 32-bit register?
>>>
>>>      Arnd
>>>
>>
>> Hi Arnd,
>>
>> I'm sorry I did not find any relevant registers in the docs or source code describing
>> it in a specific block of registers, and no close enough register definitions either.
>> They may be used by the secure firmware I imagine.
>>
>> For the register name, Amlogic refers it to "cpu_version" in their code, but it really
>> gives some details on the whole SoC and package, and socinfo seems better.
> 
> A register at address 0x220 seems a bit strange (unless there's ranges 
> you're not showing), but ROM code at this address would be fairly 
> typical. And putting version information into the ROM is also common.
> 
> Rob
> 

Hi Rob.

Indeed it's part of a larger range :
                 aobus: aobus@c8100000 {
                        compatible = "simple-bus";
                        reg = <0x0 0xc8100000 0x0 0x100000>;
                        #address-cells = <2>;
                        #size-cells = <2>;
                        ranges = <0x0 0x0 0x0 0xc8100000 0x0 0x100000>;


While scrubbing on the uboot source, I found a sort of block of registers dedicated to communicate with
the secure firmware :
AO_SEC_REG0							0x140
AO_SEC_REG1							0x144
AO_SEC_REG2							0x148
AO_SEC_TMODE_PWD0						0x160
AO_SEC_TMODE_PWD1						0x164
AO_SEC_TMODE_PWD2						0x168
AO_SEC_TMODE_PWD3						0x16C
AO_SEC_SCRATCH							0x17C
AO_SEC_JTAG_PWD0						0x180
AO_SEC_JTAG_PWD1						0x184
AO_SEC_JTAG_PWD2						0x188
AO_SEC_JTAG_PWD3						0x18C
AO_SEC_JTAG_SEC_CNTL						0x190
AO_SEC_JTAG_PWD_ADDR0						0x194
AO_SEC_JTAG_PWD_ADDR1						0x198
AO_SEC_JTAG_PWD_ADDR2						0x19C
AO_SEC_JTAG_PWD_ADDR3						0x1A0
AO_SEC_SHARED_AHB_SRAM_REG0_0					0x1C0
AO_SEC_SHARED_AHB_SRAM_REG0_1					0x1C4
AO_SEC_SHARED_AHB_SRAM_REG0_2					0x1C8
AO_SEC_SHARED_AHB_SRAM_REG1_0					0x1CC
AO_SEC_SHARED_AHB_SRAM_REG1_1					0x1D0
AO_SEC_SHARED_AHB_SRAM_REG1_2					0x1D4
AO_SEC_SHARED_AHB_SRAM_REG2_0					0x1D8
AO_SEC_SHARED_AHB_SRAM_REG2_1					0x1DC
AO_SEC_SHARED_AHB_SRAM_REG2_2					0x1E0
AO_SEC_SHARED_AHB_SRAM_REG3_0					0x1E4
AO_SEC_SHARED_AHB_SRAM_REG3_1					0x1E8
AO_SEC_SHARED_AHB_SRAM_REG3_2					0x1EC
AO_SEC_AO_AHB_SRAM_REG0_0					0x1F0
AO_SEC_AO_AHB_SRAM_REG0_1					0x1F4
AO_SEC_AO_AHB_SRAM_REG1_0					0x1F8
AO_SEC_AO_AHB_SRAM_REG1_1					0x1FC
AO_SEC_SD_CFG8							0x220
AO_SEC_SD_CFG9							0x224
AO_SEC_SD_CFG10							0x228
AO_SEC_SD_CFG11							0x22C
AO_SEC_SD_CFG12							0x230
AO_SEC_SD_CFG13							0x234
AO_SEC_SD_CFG14							0x238
AO_SEC_SD_CFG15							0x23C
AO_SEC_GP_CFG0							0x240
AO_SEC_GP_CFG1							0x244
AO_SEC_GP_CFG2							0x248
AO_SEC_GP_CFG3							0x24C
AO_SEC_GP_CFG4							0x250
AO_SEC_GP_CFG5							0x254
AO_SEC_GP_CFG6							0x258
AO_SEC_GP_CFG7							0x25C
AO_SEC_GP_CFG8							0x260
AO_SEC_GP_CFG9							0x264
AO_SEC_GP_CFG10							0x268
AO_SEC_GP_CFG11							0x26C
AO_SEC_GP_CFG12							0x270
AO_SEC_GP_CFG13							0x274
AO_SEC_GP_CFG14							0x278
AO_SEC_GP_CFG15							0x27C


As you see, the register we use here is AO_SEC_SD_CFG8...

Should I define all this block as simple-mfd and refer to it as a regmap ?

aobus: aobus@c8100000 {
	compatible = "simple-bus";
	reg = <0x0 0xc8100000 0x0 0x100000>;
	#address-cells = <2>;
	#size-cells = <2>;
	ranges = <0x0 0x0 0x0 0xc8100000 0x0 0x100000>;

	ao_secure: ao-secure@140 {
		compatible = "amlogic,meson-gx-ao-secure", "simple-mfd";
		reg = <0x0 0x140 0x0 0x140>;
	};
};

chipid {
	compatible = "amlogic,meson-gx-socinfo";
	ao-secure = <&ao_secure>;
	chip-info-reg = <0xe0>;
};

Neil