Re: [Minios-devel] [UNIKRAFT PATCHv5 38/46] plat/kvm: Get PSCI conduit method from DTB for Arm64

[Simon Kuenzer <simon.kuenzer@xxxxxxxxx>]

On 10.08.2018 09:08, Wei Chen wrote:
> From: Wei Chen <Wei.Chen@xxxxxxx>
>
> 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. We only support PSCI-1.0 and PSCI-0.2 in this
> stage.
>
> Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx>
> ---
>   plat/kvm/arm/setup.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 44 insertions(+)
>
> diff --git a/plat/kvm/arm/setup.c b/plat/kvm/arm/setup.c
> index a74c85f..a0b1f50 100644
> --- a/plat/kvm/arm/setup.c
> +++ b/plat/kvm/arm/setup.c
> @@ -22,6 +22,7 @@
>   #include <kvm/console.h>
>   #include <uk/assert.h>
>   #include <mm.h>
> +#include <arm/cpu.h>
>   #include <uk/arch/limits.h>
>   
>   void *_libkvmplat_pagetable;
> @@ -33,6 +34,8 @@ void *_libkvmplat_dtb;
>   #define MAX_CMDLINE_SIZE 1024
>   static char cmdline[MAX_CMDLINE_SIZE];
>   
> +smcc_psci_callfn_t smcc_psci_call;
> +
>   static void _init_dtb(void *dtb_pointer)
>   {
>         int ret;
> @@ -44,6 +47,44 @@ static void _init_dtb(void *dtb_pointer)
>         uk_printd(DLVL_INFO, "Found device tree on: %p\n", dtb_pointer);
>   }
>   
> +static void _dtb_get_psci_method(void)
> +{
> +       int fdtpsci, len;
> +       const char *fdtmethod;
> +
> +       /*
> +        * We just support PSCI-0.2 and PSCI-1.0, the PSCI-0.1 would not
> +        * be supported.
> +        */
> +       fdtpsci = fdt_node_offset_by_compatible(_libkvmplat_dtb,
> +                                               -1, "arm,psci-1.0");
> +       if (fdtpsci < 0)
> +               fdtpsci = fdt_node_offset_by_compatible(_libkvmplat_dtb,
> +                                                       -1, "arm,psci-0.2");
> +       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"))
> +               smcc_psci_call = smcc_psci_hvc_call;
> +       else if (!strcmp(fdtmethod, "smc"))
> +               smcc_psci_call = smcc_psci_smc_call;
What if you find something else than hvc or smc on the device tree?

> +
> +       uk_printd(DLVL_INFO, "PSCI method: %s\n", fdtmethod);
> +       return;
> +
> +enomethod:
> +       uk_printd(DLVL_INFO, "Support PSCI from PSCI-0.2\n");
> +       smcc_psci_call = NULL;
> +}
> +
>   static void _init_dtb_mem(void)
>   {
>         extern char _text[];
> @@ -143,6 +184,9 @@ void _libkvmplat_start(void *dtb_pointer)
>   
>   	_dtb_get_cmdline(cmdline, sizeof(cmdline));
>   
> +	/* Get PSCI method from DTB */
> +       _dtb_get_psci_method();
> +
>         /* Initialize memory from DTB */
>         _init_dtb_mem();
>   
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