FYI: ACPI ASL 2.0

[Rudolf Marek]

Hi all,

Just FYI [1], maybe you already know.

There is an alternate syntax available for ACPI ASL sources.
It just converts Polish notation  of ASL to something less geeky like C
operators. It says that the tool to convert the sources is in development (to
ratain comments). I think it would make ACPI more readable if coreboot would
switch to ASL 2.0. Note that the change is only on syntax side! Latest ACPICA
iasl already decompiles to this syntax by default!

Example before:

Method (SRDY, 0, Serialized)
        {
                Store (200, Local0)     // Timeout 200ms
                While (Local0) {
                        If (And(HSTS, 0x40)) {          // IN_USE?
                                Sleep(1)                // Wait 1ms
                                Decrement(Local0)       // timeout--
                                If (LEqual(Local0, 0)) {
                                        Return (1)
                                }
                        } Else {
                                Store (0, Local0)       // We're ready
                        }
                }

Store (4000, Local0)    // Timeout 200ms (50us * 4000)
                While (Local0) {
                        If (And (HSTS, 0x01)) {         // Host Busy?
                                Stall(50)               // Wait 50us
                                Decrement(Local0)       // timeout--
                                If (LEqual(Local0, 0)) {
                                        KILL()
                                }
                        } Else {
                                Return (0)              // Success
                        }
                }

Return (1)              // Failure
        }

After:

Method (SRDY, 0, Serialized)
        {
            Local0 = 0xC8
            While (Local0)
            {
                If (HSTS & 0x40)
                {
                    Sleep (0x01)
                    Local0--
                    If (Local0 == 0x00)
                    {
                        Return (0x01)
                    }
                }
                Else
                {
                    Local0 = 0x00
                }
            }

Local0 = 0x0FA0
            While (Local0)
            {
                If (HSTS & 0x01)
                {
                    Stall (0x32)
                    Local0--
                    If (Local0 == 0x00)
                    {
                        KILL ()
                    }
                }
                Else
                {
                    Return (0x00)
                }
            }

Return (0x01)
        }

Thanks
Rudolf

[1] https://acpica.org/sites/acpica/files/ASL2.0Overview.pdf

[Marc Jones]

Hi Rudolf,

I'm for this change. I don't think it would be too invasive and should be
easy to test with the compiler.

Marc

On Mon, Sep 19, 2016 at 2:49 PM Rudolf Marek  wrote:
> Hi all,
>
> Just FYI [1], maybe you already know.
>
> There is an alternate syntax available for ACPI ASL sources.
> It just converts Polish notation  of ASL to something less geeky like C
> operators. It says that the tool to convert the sources is in development
> (to
> ratain comments). I think it would make ACPI more readable if coreboot
> would
> switch to ASL 2.0. Note that the change is only on syntax side! Latest
> ACPICA
> iasl already decompiles to this syntax by default!
>
> Example before:
>   Method (SRDY, 0, Serialized)
>     {
>             Store (200, Local0)     // Timeout 200ms
>             While (Local0) {
>                     If (And(HSTS, 0x40)) {          // IN_USE?
>                             Sleep(1)                // Wait 1ms
>                             Decrement(Local0)       // timeout--
>                             If (LEqual(Local0, 0)) {
>                                     Return (1)
>                             }
>                     } Else {
>                             Store (0, Local0)       // We're ready
>                     }
>             }
>
>             Store (4000, Local0)    // Timeout 200ms (50us * 4000)
>             While (Local0) {
>                     If (And (HSTS, 0x01)) {         // Host Busy?
>                             Stall(50)               // Wait 50us
>                             Decrement(Local0)       // timeout--
>                             If (LEqual(Local0, 0)) {
>                                     KILL()
>                             }
>                     } Else {
>                             Return (0)              // Success
>                     }
>             }
>
>             Return (1)              // Failure
>     }
>
>
> After:
>     Method (SRDY, 0, Serialized)
>     {
>         Local0 = 0xC8
>         While (Local0)
>         {
>             If (HSTS & 0x40)
>             {
>                 Sleep (0x01)
>                 Local0--
>                 If (Local0 == 0x00)
>                 {
>                     Return (0x01)
>                 }
>             }
>             Else
>             {
>                 Local0 = 0x00
>             }
>         }
>
>         Local0 = 0x0FA0
>         While (Local0)
>         {
>             If (HSTS & 0x01)
>             {
>                 Stall (0x32)
>                 Local0--
>                 If (Local0 == 0x00)
>                 {
>                     KILL ()
>                 }
>             }
>             Else
>             {
>                 Return (0x00)
>             }
>         }
>
>         Return (0x01)
>     }
>
>
> Thanks
> Rudolf
>
> [1] https://acpica.org/sites/acpica/files/ASL2.0Overview.pdf