Re: [Minios-devel] [UNIKRAFT PATCHv4 33/43] plat/kvm: Get PSCI conduit method from DTB for arm64

[Wei Chen <Wei.Chen@xxxxxxx>]

Hi Julien,

> -----Original Message-----
> From: Julien Grall <julien.grall@xxxxxxx>
> Sent: 2018年7月16日 21:14
> To: Wei Chen <Wei.Chen@xxxxxxx>; minios-devel@xxxxxxxxxxxxxxxxxxxx;
> simon.kuenzer@xxxxxxxxx
> Cc: Kaly Xin <Kaly.Xin@xxxxxxx>; nd <nd@xxxxxxx>
> Subject: Re: [Minios-devel] [UNIKRAFT PATCHv4 33/43] plat/kvm: Get PSCI
> conduit method from DTB for arm64
> 
> Hi Wei,
> 
> On 06/07/18 10:03, Wei Chen wrote:
> > PSCI supports two conduit method: HVC and SMC. The method
> > would be set value in device tree's PSCI node. This value
> > would decide which instruction we should use to call PSCI
> > functions.
> >
> > Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx>
> > ---
> >   plat/common/include/arm/arm64/cpu.h |  6 +++++
> >   plat/kvm/arm/setup.c                | 39 +++++++++++++++++++++++++++++
> >   2 files changed, 45 insertions(+)
> >
> > diff --git a/plat/common/include/arm/arm64/cpu.h
> b/plat/common/include/arm/arm64/cpu.h
> > index 7c79462..cf0f6a2 100644
> > --- a/plat/common/include/arm/arm64/cpu.h
> > +++ b/plat/common/include/arm/arm64/cpu.h
> > @@ -70,3 +70,9 @@
> >   #define   SYSREG_WRITE(reg, val)      \
> >     __asm__ __volatile__("msr " __STRINGIFY(reg) ", %0" \
> >                                     : : "r" ((uint64_t)(val)))
> > +
> > +
> 
> No need for 2 newline here.

I will remove one.

> 
> > +/* PSCI conduit types */
> > +#define PSCI_METHOD_NONE   0x0
> > +#define PSCI_METHOD_HVC            0x1
> > +#define PSCI_METHOD_SMC            0x2
> 
> It feels like this should be an enum.
> 

Ok.

> > diff --git a/plat/kvm/arm/setup.c b/plat/kvm/arm/setup.c
> > index 685308c..b7f3e47 100644
> > --- a/plat/kvm/arm/setup.c
> > +++ b/plat/kvm/arm/setup.c
> > @@ -35,6 +35,7 @@
> >   #include <uk/plat/console.h>
> >   #include <uk/assert.h>
> >   #include <uk/essentials.h>
> > +#include <arm/cpu.h>
> >   #include <arm/cpu_defs.h>
> >
> >   #define MAX_CMDLINE_SIZE 1024
> > @@ -46,6 +47,8 @@ void *_libkvmplat_stack_top;
> >   void *_libkvmplat_mem_end;
> >   void *_libkvmplat_dtb;
> >
> > +int psci_method;
> > +
> >   static void _init_dtb(void *dtb_pointer)
> >   {
> >     int ret;
> > @@ -83,6 +86,39 @@ enocmdl:
> >     strcpy(cmdline, CONFIG_UK_NAME);
> >   }
> >
> > +static void _dtb_get_psci_method(void)
> > +{
> > +   int fdtpsci, len;
> > +   const char *fdtmethod;
> > +
> > +   fdtpsci = fdt_node_offset_by_compatible(_libkvmplat_dtb,
> > +                                           0, "arm,psci-0.2");
> > +   if (fdtpsci < 0)
> > +           fdtpsci = fdt_node_offset_by_compatible(_libkvmplat_dtb,
> > +                                                   0, "arm,psci-0.1");
> 
> Looking at the bindings, I can't find the compatible arm,psci-0.1. Where
> does it come from?
> 
> Also, you may want to check the compatible "arm,psci-1.0".
> 

Oh, yes, it's typo, for PSCI we have 3 compatible string:
"arm,psci-1.0",        
"arm,psci-0.2",        
"arm,psci, ==> this one is PSCI-0.1

And in this code, I should use "arm,psci-1.0".


> > +   if (fdtpsci < 0) {
> > +           uk_printd(DLVL_INFO, "No PSCI conduit found in DTB\n");
> > +           goto enomethod;
> > +   }
> > +
> > +   fdtmethod = fdt_getprop(_libkvmplat_dtb, fdtpsci, "method", &len);
> > +   if (!fdtmethod || (len <= 0)) {
> > +           uk_printd(DLVL_INFO, "No PSCI method found\n");
> > +           goto enomethod;
> > +   }
> > +
> > +   if (!strcmp(fdtmethod, "hvc"))
> > +           psci_method = PSCI_METHOD_HVC;
> > +   else if (!strcmp(fdtmethod, "smc"))
> > +           psci_method = PSCI_METHOD_SMC;
> > +
> > +   uk_printd(DLVL_INFO, "PSCI method: %s, %d\n", fdtmethod, psci_method);
> > +   return;
> > +
> > +enomethod:
> > +   psci_method = PSCI_METHOD_NONE;
> > +}
> > +
> >   static void _init_dtb_mem(void)
> >   {
> >     extern char _text[];
> > @@ -146,6 +182,9 @@ void _libkvmplat_start(void *dtb_pointer)
> >     /* Get command line from DTB */
> >     _dtb_get_cmdline(cmdline, sizeof(cmdline));
> >
> > +   /* Get PSCI method from DTB */
> > +   _dtb_get_psci_method();
> > +
> >     /* Initialize memory from DTB */
> >     _init_dtb_mem();
> >
> >
> 
> Cheers,
> 
> 
> --
> Julien Grall
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