On 08.02.2016 19:53, 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>
> ---
> lib/powerpc/asm/rtas.h | 26 +++++++++++
> lib/powerpc/io.c | 2 +
> lib/powerpc/rtas.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++
> lib/ppc64/asm/rtas.h | 1 +
> powerpc/Makefile.common | 1 +
> 5 files changed, 150 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/rtas.c b/lib/powerpc/rtas.c
> new file mode 100644
> index 0000000000000..7fcd667513087
> --- /dev/null
> +++ b/lib/powerpc/rtas.c
> @@ -0,0 +1,120 @@
> +/*
> + * 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/io.h>
> +#include <asm/rtas.h>
> +
> +#if defined(__powerpc64__)
> +struct func_ptr {
> + unsigned long ptr;
> + unsigned long toc;
Theoretically, there should be a third value "env" or so here (see
<http://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#FUNC-DES>),
but for C-code it likely does not matter.
> +};
> +static struct func_ptr rtas_entry_funcptr;
> +#endif
> +typedef void (*rtas_entry_t)(unsigned long);
> +static rtas_entry_t enter_rtas;
> +static struct rtas_args rtas_args;
> +static struct spinlock 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)
> +{
> + const struct fdt_property *prop;
> + unsigned long entry;
> + u32 *data;
> + int len;
> +
> + if (!dt_available()) {
> + printf("%s: No device tree!\n", __func__);
> + abort();
> + }
> +
> + prop = fdt_get_property(dt_fdt(), rtas_node(),
> + "linux,rtas-entry", &len);
> + if (!prop) {
> + printf("%s: /rtas/linux,rtas-entry: %s\n",
> + __func__, fdt_strerror(len));
> + abort();
> + }
> +
> + data = (u32 *)prop->data;
> + entry = (unsigned long)fdt32_to_cpu(*data);
> +
> +#if defined(__powerpc64__)
> + rtas_entry_funcptr.ptr = entry;
> + enter_rtas = (rtas_entry_t)&rtas_entry_funcptr;
> +#else
> + enter_rtas = (rtas_entry_t)entry;
> +#endif
> +}
> +
> +int rtas_token(const char *service)
> +{
> + const struct fdt_property *prop;
> + u32 *token;
> +
> + prop = fdt_get_property(dt_fdt(), rtas_node(), service, NULL);
> + if (prop) {
> + token = (u32 *)prop->data;
> + return fdt32_to_cpu(*token);
> + }
> + return RTAS_UNKNOWN_SERVICE;
> +}
> +
> +int rtas_call(int token, int nargs, int nret, int *outputs, ...)
> +{
> + va_list list;
> + int ret, i;
> +
> + spin_lock(&lock);
> +
> + rtas_args.token = cpu_to_be32(token);
> + rtas_args.nargs = cpu_to_be32(nargs);
> + rtas_args.nret = cpu_to_be32(nret);
> + rtas_args.rets = &rtas_args.args[nargs];
> +
> + va_start(list, outputs);
> + for (i = 0; i < nargs; ++i)
> + rtas_args.args[i] = cpu_to_be32(va_arg(list, u32));
> + va_end(list);
> +
> + for (i = 0; i < nret; ++i)
> + rtas_args.rets[i] = 0;
> +
> + enter_rtas(__pa(&rtas_args));
> +
> + if (nret > 1 && outputs != NULL)
> + for (i = 0; i < nret - 1; ++i)
> + outputs[i] = be32_to_cpu(rtas_args.rets[i + 1]);
> +
> + ret = nret > 0 ? be32_to_cpu(rtas_args.rets[0]) : 0;
> +
> + spin_unlock(&lock);
> + return ret;
> +}
> +
> +void rtas_power_off(void)
> +{
> + printf("RTAS power-off returned %d\n",
> + rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1));
> + assert(0);
> +}
As discussed in IRC already, that assert() can cause an endless loop...
but apart from that, the patch looks fine to me.
Thomas
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