Re: [coreboot] FYI: ACPI ASL 2.0

[Marc Jones]

On Tue, Sep 20, 2016 at 1:02 PM Duncan Laurie  wrote:
> So far I've been asking people in ACPI patches to not introduce ASL 2.0
> syntax into existing ASL code as it can be confusing if the two are mixed.
> So we should either convert everything or at least only use ASL 2.0 syntax
> in new files.

I agree. We don't want mixed. Maybe a comment at the top of the file if it
is an ACPI2.0 format.
> The problem with auto-converting sources with the disassembly/assembly
> trick is you lose all the comments.

I don't know how many changes there are and how much could be partial
automated. We need to understand the scale of the work involved and have a
plan to integrate the changes.
> The problem with doing it by hand is it very easy to mess something up.

But that *should* be easy to check. The disassembly should match before and
after.

Marc
> -duncan
>
> On Tue, Sep 20, 2016 at 11:39 AM, Marc Jones  wrote:
> > 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

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