On Mon, Feb 22, 2016 at 02:26:28PM +1100, David Gibson wrote:
> On Fri, Feb 19, 2016 at 04:58:22PM +0100, Andrew Jones wrote:
> > Add enough RTAS support to start adding RTAS commands. Just add
> > power-off for now.
> >
> > Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx>
> > Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx>
> > Tested-by: Laurent Vivier <lvivier@xxxxxxxxxx>
> > Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> > ---
> > lib/powerpc/asm/rtas.h | 26 +++++++++
> > lib/powerpc/io.c | 2 +
> > lib/powerpc/rtas.c | 139 ++++++++++++++++++++++++++++++++++++++++++++++++
> > lib/ppc64/asm/rtas.h | 1 +
> > powerpc/Makefile.common | 1 +
> > 5 files changed, 169 insertions(+)
> > create mode 100644 lib/powerpc/asm/rtas.h
> > create mode 100644 lib/powerpc/rtas.c
> > create mode 100644 lib/ppc64/asm/rtas.h
> >
> > diff --git a/lib/powerpc/asm/rtas.h b/lib/powerpc/asm/rtas.h
> > new file mode 100644
> > index 0000000000000..522225bcb6de3
> > --- /dev/null
> > +++ b/lib/powerpc/asm/rtas.h
> > @@ -0,0 +1,26 @@
> > +#ifndef _ASMPOWERPC_RTAS_H_
> > +#define _ASMPOWERPC_RTAS_H_
> > +/*
> > + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@xxxxxxxxxx>
> > + *
> > + * This work is licensed under the terms of the GNU LGPL, version 2.
> > + */
> > +#include <libcflat.h>
> > +
> > +#define RTAS_UNKNOWN_SERVICE (-1)
> > +
> > +struct rtas_args {
> > + u32 token;
> > + u32 nargs;
> > + u32 nret;
> > + u32 args[16];
> > + u32 *rets;
> > +};
> > +
> > +extern void rtas_init(void);
> > +extern int rtas_token(const char *service);
> > +extern int rtas_call(int token, int nargs, int nret, int *outputs, ...);
> > +
> > +extern void rtas_power_off(void);
> > +
> > +#endif /* _ASMPOWERPC_RTAS_H_ */
> > diff --git a/lib/powerpc/io.c b/lib/powerpc/io.c
> > index ef90946fb1131..c4c61ea8ac1cf 100644
> > --- a/lib/powerpc/io.c
> > +++ b/lib/powerpc/io.c
> > @@ -7,6 +7,7 @@
> > */
> > #include <libcflat.h>
> > #include <asm/spinlock.h>
> > +#include <asm/rtas.h>
> >
> > extern void halt(int code);
> > extern void putchar(int c);
> > @@ -15,6 +16,7 @@ static struct spinlock print_lock;
> >
> > void io_init(void)
> > {
> > + rtas_init();
> > }
> >
> > void puts(const char *s)
> > diff --git a/lib/powerpc/rtas.c b/lib/powerpc/rtas.c
> > new file mode 100644
> > index 0000000000000..464d066d3c220
> > --- /dev/null
> > +++ b/lib/powerpc/rtas.c
> > @@ -0,0 +1,139 @@
> > +/*
> > + * powerpc RTAS
> > + *
> > + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@xxxxxxxxxx>
> > + *
> > + * This work is licensed under the terms of the GNU LGPL, version 2.
> > + */
> > +#include <libcflat.h>
> > +#include <libfdt/libfdt.h>
> > +#include <devicetree.h>
> > +#include <asm/spinlock.h>
> > +#include <asm/hcall.h>
> > +#include <asm/io.h>
> > +#include <asm/rtas.h>
> > +
> > +#define RTAS_BLOB_WORDS 8
> > +
> > +#if defined(__powerpc64__)
> > +struct func_ptr {
> > + unsigned long ptr;
> > + unsigned long toc;
> > +};
> > +static struct func_ptr rtas_entry_funcptr;
> > +#endif
> > +static u32 rtas_blob[RTAS_BLOB_WORDS];
> > +typedef void (*rtas_entry_t)(unsigned long);
> > +static rtas_entry_t enter_rtas;
> > +static struct rtas_args rtas_args;
> > +static struct spinlock rtas_lock;
> > +
> > +static int rtas_node(void)
> > +{
> > + int node = fdt_path_offset(dt_fdt(), "/rtas");
> > +
> > + if (node < 0) {
> > + printf("%s: /rtas: %s\n", __func__, fdt_strerror(node));
> > + abort();
> > + }
> > +
> > + return node;
> > +}
> > +
> > +void rtas_init(void)
> > +{
> > + bool broken_sc1 = hcall_have_broken_sc1();
> > + int node = rtas_node(), len, words, i;
> > + const struct fdt_property *prop;
> > + u32 *data, *insns;
> > +
> > + if (!dt_available()) {
> > + printf("%s: No device tree!\n", __func__);
> > + abort();
> > + }
> > +
> > + prop = fdt_get_property(dt_fdt(), node,
> > + "linux,rtas-entry", &len);
> > + if (!prop) {
> > + printf("%s: /rtas/linux,rtas-entry: %s\n",
> > + __func__, fdt_strerror(len));
> > + abort();
> > + }
> > +
> > + data = (u32 *)prop->data;
> > + insns = (u32 *)(unsigned long)fdt32_to_cpu(*data);
> > +
> > + prop = fdt_get_property(dt_fdt(), node, "rtas-size", &len);
> > + if (!prop) {
> > + printf("%s: /rtas/rtas-size: %s\n",
> > + __func__, fdt_strerror(len));
> > + abort();
> > + }
> > + data = (u32 *)prop->data;
> > + words = (int)fdt32_to_cpu(*data)/4;
> > + assert(words <= RTAS_BLOB_WORDS);
> > +
> > + for (i = 0; i < words; ++i) {
> > + rtas_blob[i] = be32_to_cpu(insns[i]);
> > + if (broken_sc1 && rtas_blob[i] == SC1)
> > + rtas_blob[i] = SC1_REPLACEMENT;
> > + }
>
> Hmm.. in general it's not guaranteed that you can copy around the RTAS
> blob and have it still work. But.. you're working essentially at the
> same level as SLOF here, rather than a "normal" OS and I think SLOF
> must make the same assumption. So I guess it's ok.
I can edit the instructions in place, like I was doing before, as now...
>
> > +#if defined(__powerpc64__)
>
> Technically this ifdef should be based on the ABI version, rather than
> __powerpc64__, but I'm not sure if there are standard #defines for that.
>
> > + rtas_entry_funcptr.ptr = (unsigned long)rtas_blob;
> > + enter_rtas = (rtas_entry_t)&rtas_entry_funcptr;
> > +#else
> > + enter_rtas = (rtas_entry_t)rtas_blob;
> > +#endif
>
> I think you may want to have an actual coded enter_rtas function,
> rather than just constructing a function pointer around the raw blob.
> For one thing it should reduce the ugly ABI version #ifdefs. More
> importantly though, you can use it to set up the correct MSR state for
> entry into RTAS (IR, DR, EE off, big-endian, ..). At the moment all
> your code runs in a suitable MSR state to call directly into RTAS, but
> that will probably change fairly soon.
...I see I don't need to edit all instructions wrt to endianness. The
"call RTAS with BE state", even if running LE, was something I had
missed, which means the above code (converting the BE blob to cpu
endian) was the wrong thing to do. I've now added an assembler enter_rtas
function, which doesn't do anything special yet, but I think I know what
needs to be done with it, at least for LE enablement.
Thanks,
drew
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